September 2, 2024 • 35 mins
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What if your pet fish could wreak havoc on Australia's ecosystems? Turns out, that's precisely what they'll do if they end up in our waterways.
In today's episode, Dr. Siwan Lovett sits down with freshwater fish biologist Dr Mariah Millington, who reveals the surprising capacity for non-native pet fish to damage and degrade Australia's freshwater ecosystems, and particularly the native fish that live within them. Discover how to best dispose of dead pet fish, how common goldfish and other popular pet species can grow to alarming sizes and cause severe ecological damage when released, Mariah's undercover research into forums and marketplaces on the Deep web, and some of the specific species which pose significant ecological risks to Australian native fish, whose populations are already estimated to be less than 10% of their pre-colonisation numbers.
Mariah pulls back the curtain on the underground world of illegal fish trade and the challenges in regulating this thriving online market. You'll be intrigued by the prevalence of pet fish in Australian households and the secretive subculture of basement breeders who bypass legal regulations through platforms like Facebook and Gumtree. From the complexities of transporting fish over long distances to the hidden layers of the web where these transactions occur, our conversation uncovers the dark side of the pet fish industry and the ecological risks it poses.
The threats don't stop there—Tilapia and other invasive fish species are making alarming inroads into Australia's waterways. Tilapia in particular continue to head further south. Learn about the reproductive strategies that make tilapia particularly dangerous and the potential for hybridization to increase their invasive potential. Mariah discusses the importance of public education, biosecurity measures, and promoting native fish conservation initiatives.
This episode is a compelling call to action for protecting our native fish populations and the ecosystems they depend on.
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:00):
As a child you don't understand the way that could
impact anything.
The diseases and things thefish carry pass through the
water and if they don't getfiltered out properly it just
goes straight into our riversand things.
But it's something that I don'tthink people were taught when
we were younger that that wasn'tthe way to do it.
You know, burying a fishdoesn't seem the natural kind of
way, because they're fish, theybelong in the water, but they
(00:21):
don't belong in our water.
They belong in the water, butthey don't belong in our water.
Speaker 2 (00:27):
They're not from around here so they don't need
to go into our waterways.
Hello and welcome to Take Me tothe River, where we're sharing
stories and inspiring hope withextraordinary people who care
for our rivers.
(00:48):
I'm your host, dr Shu-AnneLovett.
Today, I'm talking to MariahMillington.
Mariah's a freshwater fishbiologist and her research
focuses on non-native fishinvasions and impacts in
Australian freshwater systems.
She is a woman who loves to askquestions and she recently
(01:08):
received her doctorate fromGriffith University.
Her thesis was looking at theonline trade of potentially
invasive freshwater fish and thekey factors into how they're
being introduced into ourwaterways.
The number of native freshwaterfish in Australia are estimated
to be less than 10% ofpre-European levels, with
several factors contributing tothis decline.
(01:28):
Local extinctions have beenoccurring for several species
and we now have many of ournative fish populations at risk.
One of the most significantchallenges we face are the
impacts of non-native fish onour native fish.
Currently, there's 27 pet fishspecies yes, that's right pet
fish species established inrivers and lakes around
(01:49):
Australia, and they're thingslike goldfish.
These threaten our native fish,their habitats and the rivers
we care so much about.
With hundreds of species offreshwater fish in our pet
stores and in fish tanks acrossAustralia.
We need to be thinking aboutthe impact this could possibly
have on our native fish.
In our conversation with Mariah,we find out how she went
(02:11):
undercover so that she couldwork through the deep web where
a lot of these trades ofnon-native fish occur.
And these fish, whether they'resmall or large, have an impact
on the environments that ournative fish rely upon.
They often eat the food thatour native fish need and
sometimes even eat the babies ofour native fish.
So this is a huge problem Withhundreds of species of
(02:33):
freshwater pet fish in petstores and fish tanks across
Australia.
We need to raise our awarenessabout how, when a fish dies, or
even if it's alive, you don'tthrow your fish in the river,
and you most certainly don'tflush it down the toilet.
Well, mariah, it's wonderful tohave you here with us today and
with this great title Don'tThrow your Pet Fish in the River
(02:56):
.
And here's why.
How did you come to be lookingat pet fish?
Speaker 1 (03:01):
It all felt a bit accidental in the best kind of
way.
I fell into it after meetingBonnie Holmes, who works in
biosecurity Queensland, and sheasked me to look into some grey
list information.
And I misinterpreted that asthe grey list, which is a big
middle ground for legislation inAustralia, but she meant just
publications that hadn't beenactually physically published
yet.
So a bit of an accident.
(03:23):
But research for me always feltlike the right path.
My mom said when I was littleI'd hound her with questions on
everything around me and she hadto start buying, you know,
those big, chunky encyclopediabooks back in the 90s because we
didn't have a computer or theinternet back then, just so she
could figure out what the answerwas for everything.
So research always felt theright kind of path and fit for
me.
And then, going into Griffith, Iwas able to look at a ton of
(03:47):
different animals and plants,but fish kind of stuck out for
me a lot, mostly when I went outinto Narren Lake and did field
work.
It was just after a really bigflood up north and the water had
slowly started to trickle intothe lake and you could actually
see as it was coming into thedry riverbed and that lake area
fish right on the front.
It was fascinating to see themright at the very beginning of
that flood border.
So for me that was kind of theturning point that went, wow,
(04:10):
these are some amazingAustralian natives moving down
our rivers and things.
So the passion sparked fromthere.
And then having some reallyfantastic lecturers who were
really passionate about theirown research and things, so that
was the fish world for me.
Was I got hooked?
Speaker 2 (04:25):
literally, Literally hooked on fish.
Yes, and so Griffith Universitydoes a lot of work on our
native fish.
When we use the term pet fish,what sort of fish have you been
looking at?
Because they're not necessarilyour natives, are they no pet?
Speaker 1 (04:40):
is any kind of tropical freshwater is my field.
So anything from goldfish tothe cichlids, the six-foot
alligator, gar, things like thenative catfish from South
America, any kind of pet fishyou can buy to keep at home for
non-food purposes I know somepeople do buy things like
goldfish to eat, but I just lookat them from a pet perspective.
Speaker 2 (05:04):
So goldfish to eat?
You wouldn't get a lot of foodout of the goldfish that I tend
to see in the aquarium.
Do they grow them at home?
Speaker 1 (05:12):
Well, so goldfish grow as big as their tank.
So if you release them into theponds and rivers and things,
they can get to dinner platesize.
So 30 centimetres or bigger.
So that's why it's important tokeep them out of our waterways,
because they'll just keepgrowing and growing or bigger.
Speaker 2 (05:24):
So that's why it's important to keep them out of
our waterways because they'lljust keep growing and growing.
So in your research, these fishlike we have that joke about
fish being flushed down thetoilet, but do people actually
do that?
Speaker 1 (05:33):
Yes, and I have to say, unfortunately, I was one of
those as a kid.
Speaker 2 (05:36):
Oh my goodness, this isn't a confessions show.
Speaker 1 (05:40):
No, don't, don't dub me in, but as a, as a child, you
don't.
You don't understand the, theway that could impact anything.
The diseases and things thefish carry pass through the
water and if they don't getfiltered out properly, it just
goes straight into our riversand things.
But it's something that I don'tthink people were taught when
we were younger that that wasn'tthe way to do it.
You know, burying a fishdoesn't seem doesn't seem the
natural kind of way, becausethey're fish, they belong in the
(06:03):
water.
But they don't belong in ourwater.
They're not from around here,so they don't need to go into
our waterways.
Speaker 2 (06:09):
Yeah, a good point.
You're right, because it doesfeel weird burying a goldfish.
You'd think it should be outfree in the water.
So, Mariah, in your work isthere a particular type of fish
that's popping up in our riversand waterways?
Speaker 1 (06:24):
Great question.
It seems to be mostly cichlidscoming up.
Recently there was a lot ofCyprinidae, which is the
goldfish, the guppies, theSiamese fighting kind of coming
up everywhere, but cichlids seemto be the more predominant now.
Things like jaguar cichlids,which is these quite large fish
that are brown and white, thatare predatory, and they're
popping up in the Cairns areaThey've just naturalised there.
(06:47):
Cichlids such as the peacockbass as well they haven't
naturalised but they're comingup and things like jackdempsy,
which are named after the boxers.
They are quite aggressive.
They're becoming more and moreof a problem up and down the
eastern side of Australia, butalso farther north as well,
along the northern area too.
Speaker 2 (07:03):
So when you say cichlid, is that like a species
or a family name?
Are there different sorts ofcichlids from what I'm hearing?
Do they have particularfeatures?
Speaker 1 (07:12):
Yes, so the cichlids is the cichlidae family and it's
just the grouping.
Cichlid is what the pet fishowners will know them by, and
the sellers and things.
It's like roses.
So roses is the group thateveryone's quite familiar with.
That's the group of plants, andyou can go down to the species
as well.
So you could say, oh, it's thistype of rose, that type of rose
(07:34):
.
So I could say a peacock basscichlid.
Or I could say a jack dempseycichlid, that kind of yeah.
Speaker 2 (07:40):
In terms of pets, how many people have fish as pets?
Is it sort of a common pet forAustralians to have?
Speaker 1 (07:49):
Yes, pets fish are the most numerous kept in
Australia.
It's the number one.
We have more pet fish kept inhomes in Australia than dogs and
cats combined.
So it's really common, yep.
Speaker 2 (07:59):
That's amazing.
I really wouldn't have thoughtthat.
And how on earth did you dothat research?
How did you find that out?
Speaker 1 (08:09):
There's this fantastic pet, the Pet
Federation of Australia thatdoes the surveys around and
that's how they have it.
So, thankfully, I didn't haveto go and survey a huge pool of
Australians to figure out whatfish they have.
So that data's there,thankfully.
But there's something like 20million pet fish kept in
Australia, and that doesn'tinclude what is in pet stores,
that's being bred in basementsand things as well.
So we have a really bigpopulation of fish here in
(08:29):
Australia and not many of thoseare in our waterways yet, but
there's a huge potential forthem to get out quite easily.
Speaker 2 (08:37):
Wow, I'm amazed.
I had no idea that that was thecase, and I just caught on to
something then about peoplebreeding in basements.
Can you tell me a bit moreabout what's happening there?
Speaker 1 (08:46):
Yes, so backyard breeders is what you technically
generally hear when you thinkabout dog breeding and cat
breeding and things.
But we say basement breedersbecause a lot of people have
really retrofitted theirbasements out to breed these
fish and in Australia it'sbecoming more and more popular.
There's the influx of peoplemoving on to the online
marketplace, so Facebook peopleselling through Facebook
(09:09):
marketplace, gumtree there areauction sites and things you can
go to, as well as in-personones they have from different
schools and community halls andthings, but it's becoming more
common for people to startselling it.
It's a good way to make money,but unfortunately it isn't in
Queensland at least that's wheremost of my research was based.
You need to have a business ABN, and so it becomes kind of a
(09:30):
gray area as well, because itshouldn't be legally occurring
but there's no real consequencesfor it as well.
Speaker 2 (09:38):
Wow.
So in terms of the regulatoryenvironment, then what I'm
hearing is a lot of people arejust sort of bypassing that and
using social media and othersites to actually start trading
fish.
Speaker 1 (09:50):
Absolutely yes.
That was what most of mydoctorate at Griffith was about
was looking at that online worldof trade.
It's something that we don'treally understand very well.
There's no real dedicatedmonitoring in Australia for a
team or even a person who sitsdown and regularly looks at
what's available online for sale, and what I found was shocking.
So we have protected sightieslisted fish that shouldn't even
(10:12):
be in Australia, let alone beingsold on Facebook and other
sites.
We have invasive species, sothings that are already here
that are already causing harm toour natives or potentially
causing harm, and we also haverisky fish, so things that we
know have caused issues overseasor are just really suitable for
our waterways, that are reallycommonly sold online and things
and it's a really big market.
(10:32):
After I stepped down fromfinishing that thesis work last
year, it's kind of ended.
No one's really looking at itanymore, so it'll be interesting
to dial back in and see whereit's going.
I can see it moving more andmore up after COVID especially
when things shifted online.
Speaker 2 (10:46):
So I'm still getting my head around fish being traded
.
How do they get posted?
Speaker 1 (10:53):
to people.
A lot of it is in-personpickups, so there are tons of
Facebook groups and Gumtreelistings where people can come
and pick them up, but there's noregulation really on what kind
of animals you can send throughthe post for fish based on the
legality.
So they don't necessarily postus and look and go, oh, that's a
fish you shouldn't be having.
It's just a fish that gets sentand a fish only needs a very
(11:13):
small amount of water in a bagand then the rest is 70% oxygen
and the fish can survive forseveral days in that bag.
So it's quite easy to sendthings around.
And one of the longest salesthat I recorded was from
Toowoomba, all the way up tonorth of Cairns, so someone was
shipping a fish from that far.
So it's really really longdistance sales and we saw
multiple reports as well Peoplewilling to drive from Melbourne
(11:35):
up to Brisbane to get illegalfish as well.
So things like alligator garand things that aren't legal in
Australia, people are willing togo for long lengths to get
these fish.
Speaker 2 (11:51):
That's amazing.
This is a whole othersubculture that I had no idea
about, and so the web is where alot of this is happening, and I
know in some of your work youwere looking at different layers
of the web.
I mean, I've heard about thedark web, but is that what
you're talking about?
Speaker 1 (12:01):
So there's three levels.
There's the surface web.
Anyone can access it.
It's something you can findeasily on Google or DuckDuckGo,
whatever kind of platform youuse search engine you use for
that.
There's the dark web, and thenthere's the deep web, and the
dark web is the one we generallythink about, the black market
kind of thing.
Then the deep web is the levelabove that and is the level
above that, and so that's thelayer where you need to have an
invitation, such as a Facebookgroup, that kind of process, or
(12:24):
you need to have an account toaccess it.
And that's where I looked atmostly was at that deep web
level Things where it's not aseasy to put on robotic kind of
scanning processes toautomatically capture the data.
It's something that is reallygritty.
You have to be there, you haveto screenshot it, you have to
record it before it goes missingto get that kind of information
(12:44):
.
Speaker 2 (12:45):
So did you have to go undercover, Mariah?
Speaker 1 (12:47):
I did.
I loved it, a lot of ethicalthings around that, but it's
hard because how can youaccurately collect that kind of
information when you have totell people that you're
monitoring them?
So it's a difficult situationthat is becoming more and more
explainable and justifiable aswe're looking more into it.
(13:09):
But no, it was.
It was fantastic.
I really enjoyed it.
It was fantastic.
I had my own account and allday it was just scrolling
Facebook, but in a good way,just looking at not not not
memes and things, just lookingat what fish people were selling
, and sometimes there was, youknow, there was a lot of really
interesting things popping up.
Sometimes it was just goldfishfor 10 or 20 posts.
Speaker 2 (13:30):
Okay, so goldfish started to get a bit old after a
while Sometimes, yeah.
So what are some of the mostexotic fish that you've seen
that are being sort of traded,yeah?
Speaker 1 (13:44):
So the Cytis listed was really interesting.
So the zebra pleco, which is atype of catfish.
It's got these really fantasticblack and white stripes and the
vividity of those is reallyappealing.
But they are Cytis listed.
They're not allowed to betraded without a certificate.
I also saw things likealligator gar which are being
sold for at their 5, 10centimeters, which is when
(14:05):
they're a baby, they're fry, butthey can grow up to six feet
and people might not realizethat when they're buying it.
Paku as well, They've got theseteeth that look like human
molars, so your back teeth, andthey use them for crushing nuts
and things.
So really fascinating fish, butseeing a lot of really cool
cichlids as well, really brightcolours.
Some of them can rival reeffish, if I can say that.
Speaker 2 (14:28):
Wow, yes, yeah.
So I think for listeners, we'llactually put a few photos up of
these fish with a very clearwarning do not buy them and
certainly do not put them in ourrivers.
So let's move to our rivers,because we do have quite a few
invasive fish in our rivers.
So many of us hear constantlyabout European carp and they are
(14:52):
having a big environmentalimpact, but there's another fish
called the tilapia, which Iknow that you know a lot about.
So could you tell us a littlebit about the tilapia and where
it's come from and why it'spotentially a big issue for us?
Speaker 1 (15:05):
Yes, so tilapia refers to a couple of different
species, so it's theAureochromis family, but also
the tilapia family as well.
It's sometimes known as theblack mangrove cichlids, the
red-bellied tilapia.
There's several that are herein Australia, not physically but
in hybrid form, and they'respreading quite rapidly up the
coast and further south as well,so up to Cairns, and we even
(15:29):
have one down in New South Walesnow, just around the
Brunswick-Hairs area.
So it is slowly moving south,which is quite concerning
because they do have the abilityto tolerate those lower
temperatures.
So they could get into thingslike the Murray-Darling Basin,
which would be a major issue,and getting down out into our
floodplain areas as well couldbe a major issue as well.
(15:50):
They're really good at muddyingup the water.
So what they do is they buildthese nests, which is not with
sticks like a bird, but justthese shallow pools and
depressions, they call them inthe mud, but to make those they
remove the plants, they removethe substrate, they muddy the
water, clouding it up, and theycan pack a lot.
(16:11):
In a small area you can get alot of nests right up to each
other and they are territorial,but if there's a density issues
they can really become a bigproblem and they remove the food
availability, they remove theplants and mudding up the water,
also issues of eutrophicationand things and healthy drinking
water for us people as well asfor animals and plants.
(16:32):
So they could become quite abig problem further south in the
basin.
Speaker 2 (16:36):
And I mean we know that European carp are also
bioengineers.
They're an amazing.
I mean you've got European carpare also bioengineers.
They're an amazing.
I mean you've got to admirethem as a fish, like they can
breathe in muddy water, but theyalso tend to dig at the bank.
So, yes, thinking about tilapiaand carp really does make me
feel quite concerned.
The other thing I've learnedabout them, which listeners may
not know, is that they're mouthbrooders.
(16:58):
Can you explain what a mouthbrooder is?
Speaker 1 (17:01):
Yes, so instead of the male and the female
releasing their eggs and sperminto the water, what they do is
the female has her eggs in hermouth and the male will
fertilise those, and then shecarries them in her mouth as a
form of parental care, and itmeans that she has a smaller
clutch, so fewer eggs, but ahigher likelihood of them
surviving, because she'sphysically protecting them with
(17:23):
her body and she doesn't eat fora while while she's doing it.
So it's really that motherlylove that is giving them that
advantage over our natives thatrelease them straight into the
water.
And it's a problem because oneof the things as we were saying
earlier about burying a fishversus flushing a fish or even
binning a fish if you take atilapia out of the water and you
don't bury it high enough, orif you just put it on the bank,
(17:44):
any water that comes up andtouches that mother's mouth
could put her eggs she'scarrying straight back into our
river.
And that's why it's soimportant to bury them above the
high water line or bin them,because that mouth breeding does
give them that really goodadvantage of transferring their
eggs later on.
Speaker 2 (17:58):
Yeah, and I guess one of the things that's happening
with these fish is that youwouldn't normally expect to find
tilapia in cooler waters, butthey seem to be able to adapt
and so that adaptation processare we looking at it, taking
years, or actually much quicker,so that they could survive in
much cooler temperatures?
Speaker 1 (18:17):
There's this process called hybrid vigor.
So hybrid vigor is when twodifferent species, they
hybridise, they make offspringand they both take aspects of
the parents and they themselvesbecome better than their parents
.
And because we have severaldifferent types of tilapia
species in Australia, whatthey're concerned about is them
hybridising and becoming coldwater tolerable.
(18:38):
I'm not sure on how fast itcould occur, but just the fact
that it's a problem here and apotential means that it could
become an issue.
Just like the problem with carphybridising and then becoming a
more virulent strain, it's aproblem that we could have with
tilapia as well, and they cansurvive quite low temperatures
already.
So moving further south intothose colder areas, those
temperate areas down south,won't be a problem for them.
Speaker 2 (19:01):
And what about some of our little tiny invasive fish
like gambusia?
Are there a few more of them onthe horizon that might possibly
go into our waterways thatyou've examined?
Speaker 1 (19:12):
Yeah, there are a lot of smaller fish coming through.
We just had Siamese fightingfish established up north, or
the reports of it, in the Darwinarea, and if we look at the
water temperature averagesacross Australia this is
something that I looked at inthe last report I did for the
Department of Agriculture andFisheries they should not be
able to survive anywhere inAustralia, they should not be
able to establish.
(19:32):
But they have.
They've established and they'rebreeding in their thousands and
so we're underprepared forthese smaller fish because we're
overlooking them.
We're thinking about thesebigger predators, like the
tilapia, like the jaguarcichlids, like the peacock bass,
all these bigger ones, butwe're overlooking these smaller
ones that could have more damagebecause they could compete
better with our little nativeslooking for that resource of the
(19:53):
things.
Speaker 2 (19:54):
Yes, our little natives are little, and you know
, I know, up around the Coomaarea we've actually
purpose-built a river for ourlittle stocky galaxids, which
were under threat from fires,and so the thought of all these
other ones coming in, as I say,it does make you tremble a
little when you have looked atthe deep web and looked at the
(20:16):
sorts of fish that people arebuying.
Are people buying them becausethey're pretty, and what's the
level of awareness that thesefish could potentially harm our
native ecosystem?
Or is that sort of not really ajoining the dots exercise?
That's happened yet.
Speaker 1 (20:33):
That biosecurity understanding.
A lot of people don't realisethey have a biosecurity
obligation in Australia to notrelease these and their
understanding of these fishcould become a problem.
There doesn't seem to be thatconnection.
A lot of people feel guiltyabout needing to euthanize their
fish if they become sickly andthere was a study in Canada
because there aren't very manyin Australia on people's
(20:54):
motivations for release, but astudy in Canada that found
people were more likely torelease their fish into a river
because they felt like it wouldbe a good burial place for the
fish rather than putting it inbins and things.
So I don't believe there's thatyet understanding of wow, these
fish can actually do harm toour environment and it's an
educational issue.
Really there's no targeted bigcampaigns throughout Australia.
(21:18):
There's smaller ones and theyseem to be good on some aspect.
But we need that targetedinformation in pet stores,
eco-labelling especially, sothat is providing information to
consumers.
So customers and people likethat before purchase so they
understand the size the fishcould grow to, whether they're
aggressive, how they get on withother different fish, how long
(21:40):
they live as well is a bigproblem.
Some of these fish can live fordecades.
You might not be ready for a15-year commitment with these
fish.
So it's something that isreally lacking in a lot of pet
stores and it's not compulsoryin Australia.
It's a participation style, andone of the things I found as
well in my research because Ilooked at ecolabeling was that a
lot of the information beingput out was incorrect.
(22:01):
So people are saying this fishlives for five years, this fish
lives for seven years, whenactually it can live up to 18.
Speaker 2 (22:08):
Wow, that's a much longer term commitment.
And the other thing that reallystruck me about what you said
there was it's a biosecurityobligation, dead or alive,
because, as you said, with thetilapia for instance, if the
eggs make it, even if the fishis dead.
If the eggs touch water, thenthey're away and presumably if
(22:31):
you flush one of these fish, ifit's dead, into the waterway, if
it's got some sort of disease,it could pass that on.
Speaker 1 (22:39):
They already are.
So we have found well, wehaven't, sorry, I've found
research where diseases fromthings like goldfish and tilapia
are already passing on to ournative fish.
So pathogens, parasites,they're already being passed
along.
And one of the bigger issues wehave is just we have that lack
of pre-invasion informationabout our ecosystems, about our
fish.
(22:59):
What's a native?
What are the native parasitesto these fish here?
What are the food web structure?
We don't understand really apristine environment before the
fish come in.
So we can't really deftlyidentify what's happened, what's
changed.
So it's difficult to kind ofdraw a line of where these
impacts are.
But we are seeing some issuesalready.
So how many more are we notunderstanding because we just
(23:21):
don't understand pre-invasion?
Speaker 2 (23:30):
Yeah, it is a problem for us with things like the
redfin perch, which carries aparticular virus called the EHN
virus that affects Macquarieperch, which is a native fish.
So you're spot on there interms of we're sort of tending
to play catch up because it'ssort of happening and we're
trying to react.
I know with tilapia that we aretrying certainly that this fish
doesn't get into theMurray-Darling Basin.
Can you tell me a bit moreabout the work that you're now
(23:50):
doing with the Murray-DarlingBasin Authority looking at this
particular fish?
Speaker 1 (23:54):
Yes.
So I have been commissioned bythe Murray-Darling Basin
Authority to produce a 10-yearexclusion strategy for them, so
2025 to 2035.
So the plan to try and keeptilapia out of the basin.
We haven't had any close callsor anything.
It's been fantastic in thebasin, really strong education
system to keep them from movingdown.
(24:15):
But we need a new plan.
The last one expired and it'lljust be carried through those
kind of principles.
So targeting things likeeducation is especially
important.
There was a study that came outa few years ago that compared
Queensland to New South Waleseducation understanding around
biosecurity for tilapia andunfortunately the resources for
New South Wales have been quitepoor.
(24:35):
A lot of the information hasgone into Queensland because
that's where tilapia are.
But the issue is, as tilapiamove down, we need to increase
the education down south as well.
So that's a really importantpart of keeping the fish out and
also monitoring and detecting.
So if we do have a fish pop up,we know what to do, we know who
to contact, we know whoseresources are available in the
area and we know what the highrisk catchments, the high risk
(24:58):
rivers and things are.
So we can go and check thoseregularly to make sure they're
not spreading, because most ofthe introductions in Australia
have been deliberate choices bypeople, and that's the issue.
They're making these wrongchoices about, releasing them,
and that's we need to target.
Most of our efforts is keepingthese fish from being moved by
people.
Speaker 2 (25:18):
Yes, I don't know that many realise, but that's
actually how.
We have a number of our specieswhere people have said, oh,
this is a great recreationalfish, I'm going to pop it in my
local stream.
It might be a trout, it mightbe a whole range of other fish
that, yeah, they may befantastic to catch, but they're
not really meant to be in ourwaterways when we're spending so
much time and effort trying tokeep our native fish alive.
(25:40):
So if you were running aneducation campaign, for instance
, who would you be targeting?
Is it wreck fishers?
Is it at the school level?
Is there a particular age group?
What sort of profile is thereof the person that we need to be
talking to?
Speaker 1 (25:57):
You're spot on there that it's the kids and the wreck
fishers.
Kids take their information,they learn home, they teach
their parents.
It's easier to talk to childrenabout it and then they take it
home rather than trying toconvince an adult to change
their ways.
But recreational fishers aswell.
We're not blaming them, ofcourse.
Most of them are doing whatthey need to do.
Most of them are going outthere.
They're fishing in the rightplaces for the right fish.
(26:20):
They're cleaning things beforethey go and coming back for the
right fish.
They're cleaning things beforethey go and coming back, so
they're not transplanting eggsor anything like that.
It's just the few who ruin itfor the many.
It's that saying, but just thatunderstanding that just because
it's a fun fish to fish for inother parts of the world, it's
not right for Australia.
We've got other great nativeswe can be targeting instead.
Or you can target things likecarp and redfin perch to help
(26:41):
remove them from our environmentand do your part.
But yes, it's the school kidsand the recreational fishers
that really need thatinformation.
And part of the educationoutreach program I did for the
Murray-Darling Basin Authoritytwo years ago was part of
recreational fisher targetedprogram on Facebook and what it
(27:01):
was was comparing the juveniletilapia with some juvenile
natives, and some peoplecouldn't see the difference.
They couldn't identify whichwas a tilapia and which was a
native.
And so there is that level ofunderstanding that we need to
improve, because there's been alot of education on the adults.
We all know what a big adulttilapia looks like.
They're big and they're blackand red.
They've got those sharp, thinlooking things, large lips, but
(27:24):
it's the juveniles, because theydo look similar to some of our
natives.
So it's that kind of level ofunderstanding we need to
increase too.
Speaker 2 (27:30):
And I think also I know that I found people
actually want to learn and theywant to understand.
So when you're actually sayingto someone, we want to teach you
how to identify native andnon-native fish, that's a much
better approach than saying weneed to let you know why you
must not do anything if you seethis fish, which is a much more
heavy-handed approach.
(27:51):
So had you looked overseas atall at campaigns where other
countries have tried to raiseawareness about invasive fish?
Are there other models fromoverseas we should be looking at
?
Speaker 1 (28:04):
There are a lot of campaigns and things, and a lot
of them seem to bemilitary-based, so that not
military as in the United StatesArmy or whatever, but more so
military messaging so it's yourresponsibility to fight this war
on fish, and that's just notsomething that really resonates
with a lot of Australians.
So it's a different type ofviewpoint here that we need to
(28:30):
be looking at.
It's the compassion side, it'sthe bandwagon.
We're all a community, we'reall together.
That's how we are done here.
We stick together.
So it is a bit different fromoverseas, but there's not many
tilapia-specific campaignsoverseas either.
They're really focused on othernon-natives as well.
So it's difficult to kind ofborrow from overseas.
It's really we're starting fromthe roots for some of these
things.
Speaker 2 (28:49):
But what I love about that insight is that, yeah,
I've never found that a militaryapproach works in Australia.
We do not respond to that, butwe do respond well to we're all
part of the same community.
Let's work on this together.
It's a much more inclusive,non-blaming approach.
Rather than you're the problem,make people part of the
solution.
Speaker 1 (29:08):
Yeah, because for many, they're not the reason
that it's happening.
It's just a few people who haveruined it for many, and so we
do need to unite to help removethis issue from Australia.
Speaker 2 (29:19):
And often those people that have released them
have done so unintentionally,not realising the impact that
releasing the fish have.
So we've talked abouteco-labelling and we've talked
about really raising awarenessof people prior to buying these
fish about the fact that it's alonger term commitment and that
there's a biosecurity issue aswell.
(29:39):
Is there other things that weneed to be doing in terms of
this threat that ornamental fishmight pose?
Speaker 1 (29:49):
The switch to natives would be a really great push.
I know some aquarium shops areactually having native displays
now, rather than having theseornamental ones, because we do
have some really beautifulnatives here, the rainbow fish.
They're called rainbow fish fora reason.
Yes, they are beautiful.
Speaker 2 (30:06):
Yes, yeah.
Speaker 1 (30:07):
And then our smaller ones as well.
But even things like barramundi.
You can get a black and whitepanda barramundi.
You know they do get larger,but how beautiful are those?
And golden about goldenbarramundi as well.
So we do have some beautifulnatives.
So, switching our thinking fromwe need to have these flashy
fish from overseas and goingwell, what about some natives?
The Angfa Society in Australia,which is the Australian and New
(30:30):
Guinea Fisheries FishersAssociation.
They have an education campaignin school, a few schools where
they go in, and they actuallyhave the kids raise some natives
.
The kids understand aconservation effort, they're
seeing what kind of natives are,and so it's a really great
thing to do.
So rather than raising agoldfish at home with your kids,
why not choose a?
Speaker 2 (30:48):
native.
Yeah, that's a great idea, andI know that my local aquarium
does have some natives.
I have seen some southern pygmyperch in there.
I've seen a few Murray cod andso it's nice to see them in
there, just providing that theylook that Murray Cod could
actually get quite big.
It's not really for the fishtank at home.
Speaker 1 (31:06):
Yes, yeah, and that eco-labelling, then, is really
important to have theinformation.
So if you do buy a fish withouttalking to someone first,
you're prepared, you're nothaving to go home and do all
this research after you'vebought the fish, you go in, you
can make your choice.
It's an informed choice, justlike when we're buying anything
else.
So smoking, you've got thethings on the packets, nutrition
labels and things.
Understanding, being informed,making those informed choices is
(31:28):
really important.
Speaker 2 (31:29):
Yeah, yeah.
So you started off in researchasking lots of questions and I
can tell you've got a veryinquiring mind and you've ended
up in fish.
What's been a really memorablemoment for you in your career so
far and you're only juststarting out, really but what's
been really memorable for you?
Speaker 1 (31:48):
All the conferences.
I have to say it's beenfantastic to connect with all
the other fishy people.
I had a great time at theNative Fish Forum talking about
the ornamental field, because itfelt like something that people
didn't really understand was aproblem, particularly for the
Murray-Darling Basin area andthings and there was a lot of
people that came and said, wow,we didn't realise that this was
an issue.
So it's, the conversations withpeople has been really shining.
(32:09):
I've been to about 20conferences already in my short
career and it's been always sogreat to see people go, wow,
this is something we need toconsider.
This is something that we needto put more research into to
understand better.
Speaker 2 (32:26):
And do you have a soft spot for a native fish in
Australia?
Speaker 1 (32:31):
Oh, I have to say, the Bozeman's rainbows, the
lovely blue and yellow, yeah,beautiful, beautiful fish, and
they're a plucky little fish aswell.
All the rainbows, they all haveconservation statuses, but
they're still plodding alongquite well, most of them.
Speaker 2 (32:46):
So the rainbow fish for me, oh great.
Well, we'll try and find apicture of that to put along
with the show notes.
So we're getting to the end ofour conversation, which I've
thoroughly enjoyed.
Thank you so much.
I want to ask you threequestions that we ask everybody.
Do you have a favourite riveror a waterway or body of water?
Speaker 1 (33:06):
Oh, I'd have to say Narin Lakes.
It's out near Lightning Bridge,so the northern New South Wales
and that was where I was reallyon country, really doing that
work.
It was a plant-based one, butthe number of animals I saw and
the education and learning I gotfrom the Aboriginal range is
about just even the stars inthat area, learning about the
Milky Way, just being there, itjust felt so connected.
(33:29):
So the Narren Lakes area isdefinitely a favourite part of
Australia for me, but there area lot.
It's hard to choose one, isn'tit?
Speaker 2 (33:37):
It is because we're so blessed with so many
different river environmentshere as well.
And so this leads on to my nextone, which is where do you feel
most connected to country andto nature?
And it sounded like NarrenLakes was one of those places.
Speaker 1 (33:49):
Yes, yeah, it's been a little while since I've been
out there so I'd love to go backwhen it's in flood so I can see
the fish.
But just in anywhere outside,really in the just getting out
in a park, I'm down in theNepean River area.
Beautiful down there along therivers, just even if it's not in
a river, next to a river isgreat.
Hearing that getting out ontothe land.
Speaker 2 (34:10):
Fantastic.
And finally, Mariah, what isdriving you to do what you do?
Good question.
Speaker 1 (34:15):
I think it's curiosity if I can say that.
Speaker 2 (34:18):
You certainly can.
Speaker 1 (34:20):
Just finding out, just seeing.
Why is that like that?
Why are we having this?
What is there?
Speaker 2 (34:28):
It's just the why I think you remind me so much of
my little brother.
I did a lot of sort of care forhim.
I'm nine years older than himand at one stage he just kept
saying but why, but, why, butwhy?
Thank you so much for spendingsome time with us.
I know that our listeners aregoing to really enjoy this
podcast episode and, for anyoneinterested, we'll put some show
(34:51):
notes to go along with Mariah'stalk this afternoon and you can
look up and find out even moreabout the work she's doing.
So thank you, mariah, reallyappreciate having you on the
show and we will keep in touch.
Thank you, mariah.
I really appreciate having youon the show and we will keep in
touch, thank you.
Thank you.
You can subscribe to Take Me tothe River wherever you get your
(35:11):
podcasts.
Visit arrcau forward slashpodcast to learn more.
That's arrcau forward slashpodcast.
We acknowledge and respectAboriginal and Torres Strait
Islander peoples as thetraditional and continuing
custodians of the country andthe rivers on which we live,
(35:33):
learn, love and play.
We respect and learn fromelders, past, present and
emerging, valuing theirknowledge, insights, cultures
and connections to the waterwayswe all love and care for.
As a child you don't understand the way that could
impact anything.
The diseases and things thefish carry pass through the
water and if they don't getfiltered out properly it just
goes straight into our riversand things.
But it's something that I don'tthink people were taught when
we were younger that that wasn'tthe way to do it.
You know, burying a fishdoesn't seem the natural kind of
way, because they're fish, theybelong in the water, but they
(00:21):
don't belong in our water.
They belong in the water, butthey don't belong in our water.
Speaker 2 (00:27):
They're not from around here so they don't need
to go into our waterways.
Hello and welcome to Take Me tothe River, where we're sharing
stories and inspiring hope withextraordinary people who care
for our rivers.
(00:48):
I'm your host, dr Shu-AnneLovett.
Today, I'm talking to MariahMillington.
Mariah's a freshwater fishbiologist and her research
focuses on non-native fishinvasions and impacts in
Australian freshwater systems.
She is a woman who loves to askquestions and she recently
(01:08):
received her doctorate fromGriffith University.
Her thesis was looking at theonline trade of potentially
invasive freshwater fish and thekey factors into how they're
being introduced into ourwaterways.
The number of native freshwaterfish in Australia are estimated
to be less than 10% ofpre-European levels, with
several factors contributing tothis decline.
(01:28):
Local extinctions have beenoccurring for several species
and we now have many of ournative fish populations at risk.
One of the most significantchallenges we face are the
impacts of non-native fish onour native fish.
Currently, there's 27 pet fishspecies yes, that's right pet
fish species established inrivers and lakes around
(01:49):
Australia, and they're thingslike goldfish.
These threaten our native fish,their habitats and the rivers
we care so much about.
With hundreds of species offreshwater fish in our pet
stores and in fish tanks acrossAustralia.
We need to be thinking aboutthe impact this could possibly
have on our native fish.
In our conversation with Mariah,we find out how she went
(02:11):
undercover so that she couldwork through the deep web where
a lot of these trades ofnon-native fish occur.
And these fish, whether they'resmall or large, have an impact
on the environments that ournative fish rely upon.
They often eat the food thatour native fish need and
sometimes even eat the babies ofour native fish.
So this is a huge problem Withhundreds of species of
(02:33):
freshwater pet fish in petstores and fish tanks across
Australia.
We need to raise our awarenessabout how, when a fish dies, or
even if it's alive, you don'tthrow your fish in the river,
and you most certainly don'tflush it down the toilet.
Well, mariah, it's wonderful tohave you here with us today and
with this great title Don'tThrow your Pet Fish in the River
(02:56):
.
And here's why.
How did you come to be lookingat pet fish?
Speaker 1 (03:01):
It all felt a bit accidental in the best kind of
way.
I fell into it after meetingBonnie Holmes, who works in
biosecurity Queensland, and sheasked me to look into some grey
list information.
And I misinterpreted that asthe grey list, which is a big
middle ground for legislation inAustralia, but she meant just
publications that hadn't beenactually physically published
yet.
So a bit of an accident.
(03:23):
But research for me always feltlike the right path.
My mom said when I was littleI'd hound her with questions on
everything around me and she hadto start buying, you know,
those big, chunky encyclopediabooks back in the 90s because we
didn't have a computer or theinternet back then, just so she
could figure out what the answerwas for everything.
So research always felt theright kind of path and fit for
me.
And then, going into Griffith, Iwas able to look at a ton of
(03:47):
different animals and plants,but fish kind of stuck out for
me a lot, mostly when I went outinto Narren Lake and did field
work.
It was just after a really bigflood up north and the water had
slowly started to trickle intothe lake and you could actually
see as it was coming into thedry riverbed and that lake area
fish right on the front.
It was fascinating to see themright at the very beginning of
that flood border.
So for me that was kind of theturning point that went, wow,
(04:10):
these are some amazingAustralian natives moving down
our rivers and things.
So the passion sparked fromthere.
And then having some reallyfantastic lecturers who were
really passionate about theirown research and things, so that
was the fish world for me.
Was I got hooked?
Speaker 2 (04:25):
literally, Literally hooked on fish.
Yes, and so Griffith Universitydoes a lot of work on our
native fish.
When we use the term pet fish,what sort of fish have you been
looking at?
Because they're not necessarilyour natives, are they no pet?
Speaker 1 (04:40):
is any kind of tropical freshwater is my field.
So anything from goldfish tothe cichlids, the six-foot
alligator, gar, things like thenative catfish from South
America, any kind of pet fishyou can buy to keep at home for
non-food purposes I know somepeople do buy things like
goldfish to eat, but I just lookat them from a pet perspective.
Speaker 2 (05:04):
So goldfish to eat?
You wouldn't get a lot of foodout of the goldfish that I tend
to see in the aquarium.
Do they grow them at home?
Speaker 1 (05:12):
Well, so goldfish grow as big as their tank.
So if you release them into theponds and rivers and things,
they can get to dinner platesize.
So 30 centimetres or bigger.
So that's why it's important tokeep them out of our waterways,
because they'll just keepgrowing and growing or bigger.
Speaker 2 (05:24):
So that's why it's important to keep them out of
our waterways because they'lljust keep growing and growing.
So in your research, these fishlike we have that joke about
fish being flushed down thetoilet, but do people actually
do that?
Speaker 1 (05:33):
Yes, and I have to say, unfortunately, I was one of
those as a kid.
Speaker 2 (05:36):
Oh my goodness, this isn't a confessions show.
Speaker 1 (05:40):
No, don't, don't dub me in, but as a, as a child, you
don't.
You don't understand the, theway that could impact anything.
The diseases and things thefish carry pass through the
water and if they don't getfiltered out properly, it just
goes straight into our riversand things.
But it's something that I don'tthink people were taught when
we were younger that that wasn'tthe way to do it.
You know, burying a fishdoesn't seem doesn't seem the
natural kind of way, becausethey're fish, they belong in the
(06:03):
water.
But they don't belong in ourwater.
They're not from around here,so they don't need to go into
our waterways.
Speaker 2 (06:09):
Yeah, a good point.
You're right, because it doesfeel weird burying a goldfish.
You'd think it should be outfree in the water.
So, Mariah, in your work isthere a particular type of fish
that's popping up in our riversand waterways?
Speaker 1 (06:24):
Great question.
It seems to be mostly cichlidscoming up.
Recently there was a lot ofCyprinidae, which is the
goldfish, the guppies, theSiamese fighting kind of coming
up everywhere, but cichlids seemto be the more predominant now.
Things like jaguar cichlids,which is these quite large fish
that are brown and white, thatare predatory, and they're
popping up in the Cairns areaThey've just naturalised there.
(06:47):
Cichlids such as the peacockbass as well they haven't
naturalised but they're comingup and things like jackdempsy,
which are named after the boxers.
They are quite aggressive.
They're becoming more and moreof a problem up and down the
eastern side of Australia, butalso farther north as well,
along the northern area too.
Speaker 2 (07:03):
So when you say cichlid, is that like a species
or a family name?
Are there different sorts ofcichlids from what I'm hearing?
Do they have particularfeatures?
Speaker 1 (07:12):
Yes, so the cichlids is the cichlidae family and it's
just the grouping.
Cichlid is what the pet fishowners will know them by, and
the sellers and things.
It's like roses.
So roses is the group thateveryone's quite familiar with.
That's the group of plants, andyou can go down to the species
as well.
So you could say, oh, it's thistype of rose, that type of rose
(07:34):
.
So I could say a peacock basscichlid.
Or I could say a jack dempseycichlid, that kind of yeah.
Speaker 2 (07:40):
In terms of pets, how many people have fish as pets?
Is it sort of a common pet forAustralians to have?
Speaker 1 (07:49):
Yes, pets fish are the most numerous kept in
Australia.
It's the number one.
We have more pet fish kept inhomes in Australia than dogs and
cats combined.
So it's really common, yep.
Speaker 2 (07:59):
That's amazing.
I really wouldn't have thoughtthat.
And how on earth did you dothat research?
How did you find that out?
Speaker 1 (08:09):
There's this fantastic pet, the Pet
Federation of Australia thatdoes the surveys around and
that's how they have it.
So, thankfully, I didn't haveto go and survey a huge pool of
Australians to figure out whatfish they have.
So that data's there,thankfully.
But there's something like 20million pet fish kept in
Australia, and that doesn'tinclude what is in pet stores,
that's being bred in basementsand things as well.
So we have a really bigpopulation of fish here in
(08:29):
Australia and not many of thoseare in our waterways yet, but
there's a huge potential forthem to get out quite easily.
Speaker 2 (08:37):
Wow, I'm amazed.
I had no idea that that was thecase, and I just caught on to
something then about peoplebreeding in basements.
Can you tell me a bit moreabout what's happening there?
Speaker 1 (08:46):
Yes, so backyard breeders is what you technically
generally hear when you thinkabout dog breeding and cat
breeding and things.
But we say basement breedersbecause a lot of people have
really retrofitted theirbasements out to breed these
fish and in Australia it'sbecoming more and more popular.
There's the influx of peoplemoving on to the online
marketplace, so Facebook peopleselling through Facebook
(09:09):
marketplace, gumtree there areauction sites and things you can
go to, as well as in-personones they have from different
schools and community halls andthings, but it's becoming more
common for people to startselling it.
It's a good way to make money,but unfortunately it isn't in
Queensland at least that's wheremost of my research was based.
You need to have a business ABN, and so it becomes kind of a
(09:30):
gray area as well, because itshouldn't be legally occurring
but there's no real consequencesfor it as well.
Speaker 2 (09:38):
Wow.
So in terms of the regulatoryenvironment, then what I'm
hearing is a lot of people arejust sort of bypassing that and
using social media and othersites to actually start trading
fish.
Speaker 1 (09:50):
Absolutely yes.
That was what most of mydoctorate at Griffith was about
was looking at that online worldof trade.
It's something that we don'treally understand very well.
There's no real dedicatedmonitoring in Australia for a
team or even a person who sitsdown and regularly looks at
what's available online for sale, and what I found was shocking.
So we have protected sightieslisted fish that shouldn't even
(10:12):
be in Australia, let alone beingsold on Facebook and other
sites.
We have invasive species, sothings that are already here
that are already causing harm toour natives or potentially
causing harm, and we also haverisky fish, so things that we
know have caused issues overseasor are just really suitable for
our waterways, that are reallycommonly sold online and things
and it's a really big market.
(10:32):
After I stepped down fromfinishing that thesis work last
year, it's kind of ended.
No one's really looking at itanymore, so it'll be interesting
to dial back in and see whereit's going.
I can see it moving more andmore up after COVID especially
when things shifted online.
Speaker 2 (10:46):
So I'm still getting my head around fish being traded
.
How do they get posted?
Speaker 1 (10:53):
to people.
A lot of it is in-personpickups, so there are tons of
Facebook groups and Gumtreelistings where people can come
and pick them up, but there's noregulation really on what kind
of animals you can send throughthe post for fish based on the
legality.
So they don't necessarily postus and look and go, oh, that's a
fish you shouldn't be having.
It's just a fish that gets sentand a fish only needs a very
(11:13):
small amount of water in a bagand then the rest is 70% oxygen
and the fish can survive forseveral days in that bag.
So it's quite easy to sendthings around.
And one of the longest salesthat I recorded was from
Toowoomba, all the way up tonorth of Cairns, so someone was
shipping a fish from that far.
So it's really really longdistance sales and we saw
multiple reports as well Peoplewilling to drive from Melbourne
(11:35):
up to Brisbane to get illegalfish as well.
So things like alligator garand things that aren't legal in
Australia, people are willing togo for long lengths to get
these fish.
Speaker 2 (11:51):
That's amazing.
This is a whole othersubculture that I had no idea
about, and so the web is where alot of this is happening, and I
know in some of your work youwere looking at different layers
of the web.
I mean, I've heard about thedark web, but is that what
you're talking about?
Speaker 1 (12:01):
So there's three levels.
There's the surface web.
Anyone can access it.
It's something you can findeasily on Google or DuckDuckGo,
whatever kind of platform youuse search engine you use for
that.
There's the dark web, and thenthere's the deep web, and the
dark web is the one we generallythink about, the black market
kind of thing.
Then the deep web is the levelabove that and is the level
above that, and so that's thelayer where you need to have an
invitation, such as a Facebookgroup, that kind of process, or
(12:24):
you need to have an account toaccess it.
And that's where I looked atmostly was at that deep web
level Things where it's not aseasy to put on robotic kind of
scanning processes toautomatically capture the data.
It's something that is reallygritty.
You have to be there, you haveto screenshot it, you have to
record it before it goes missingto get that kind of information
(12:44):
.
Speaker 2 (12:45):
So did you have to go undercover, Mariah?
Speaker 1 (12:47):
I did.
I loved it, a lot of ethicalthings around that, but it's
hard because how can youaccurately collect that kind of
information when you have totell people that you're
monitoring them?
So it's a difficult situationthat is becoming more and more
explainable and justifiable aswe're looking more into it.
(13:09):
But no, it was.
It was fantastic.
I really enjoyed it.
It was fantastic.
I had my own account and allday it was just scrolling
Facebook, but in a good way,just looking at not not not
memes and things, just lookingat what fish people were selling
, and sometimes there was, youknow, there was a lot of really
interesting things popping up.
Sometimes it was just goldfishfor 10 or 20 posts.
Speaker 2 (13:30):
Okay, so goldfish started to get a bit old after a
while Sometimes, yeah.
So what are some of the mostexotic fish that you've seen
that are being sort of traded,yeah?
Speaker 1 (13:44):
So the Cytis listed was really interesting.
So the zebra pleco, which is atype of catfish.
It's got these really fantasticblack and white stripes and the
vividity of those is reallyappealing.
But they are Cytis listed.
They're not allowed to betraded without a certificate.
I also saw things likealligator gar which are being
sold for at their 5, 10centimeters, which is when
(14:05):
they're a baby, they're fry, butthey can grow up to six feet
and people might not realizethat when they're buying it.
Paku as well, They've got theseteeth that look like human
molars, so your back teeth, andthey use them for crushing nuts
and things.
So really fascinating fish, butseeing a lot of really cool
cichlids as well, really brightcolours.
Some of them can rival reeffish, if I can say that.
Speaker 2 (14:28):
Wow, yes, yeah.
So I think for listeners, we'llactually put a few photos up of
these fish with a very clearwarning do not buy them and
certainly do not put them in ourrivers.
So let's move to our rivers,because we do have quite a few
invasive fish in our rivers.
So many of us hear constantlyabout European carp and they are
(14:52):
having a big environmentalimpact, but there's another fish
called the tilapia, which Iknow that you know a lot about.
So could you tell us a littlebit about the tilapia and where
it's come from and why it'spotentially a big issue for us?
Speaker 1 (15:05):
Yes, so tilapia refers to a couple of different
species, so it's theAureochromis family, but also
the tilapia family as well.
It's sometimes known as theblack mangrove cichlids, the
red-bellied tilapia.
There's several that are herein Australia, not physically but
in hybrid form, and they'respreading quite rapidly up the
coast and further south as well,so up to Cairns, and we even
(15:29):
have one down in New South Walesnow, just around the
Brunswick-Hairs area.
So it is slowly moving south,which is quite concerning
because they do have the abilityto tolerate those lower
temperatures.
So they could get into thingslike the Murray-Darling Basin,
which would be a major issue,and getting down out into our
floodplain areas as well couldbe a major issue as well.
(15:50):
They're really good at muddyingup the water.
So what they do is they buildthese nests, which is not with
sticks like a bird, but justthese shallow pools and
depressions, they call them inthe mud, but to make those they
remove the plants, they removethe substrate, they muddy the
water, clouding it up, and theycan pack a lot.
(16:11):
In a small area you can get alot of nests right up to each
other and they are territorial,but if there's a density issues
they can really become a bigproblem and they remove the food
availability, they remove theplants and mudding up the water,
also issues of eutrophicationand things and healthy drinking
water for us people as well asfor animals and plants.
(16:32):
So they could become quite abig problem further south in the
basin.
Speaker 2 (16:36):
And I mean we know that European carp are also
bioengineers.
They're an amazing.
I mean you've got European carpare also bioengineers.
They're an amazing.
I mean you've got to admirethem as a fish, like they can
breathe in muddy water, but theyalso tend to dig at the bank.
So, yes, thinking about tilapiaand carp really does make me
feel quite concerned.
The other thing I've learnedabout them, which listeners may
not know, is that they're mouthbrooders.
(16:58):
Can you explain what a mouthbrooder is?
Speaker 1 (17:01):
Yes, so instead of the male and the female
releasing their eggs and sperminto the water, what they do is
the female has her eggs in hermouth and the male will
fertilise those, and then shecarries them in her mouth as a
form of parental care, and itmeans that she has a smaller
clutch, so fewer eggs, but ahigher likelihood of them
surviving, because she'sphysically protecting them with
(17:23):
her body and she doesn't eat fora while while she's doing it.
So it's really that motherlylove that is giving them that
advantage over our natives thatrelease them straight into the
water.
And it's a problem because oneof the things as we were saying
earlier about burying a fishversus flushing a fish or even
binning a fish if you take atilapia out of the water and you
don't bury it high enough, orif you just put it on the bank,
(17:44):
any water that comes up andtouches that mother's mouth
could put her eggs she'scarrying straight back into our
river.
And that's why it's soimportant to bury them above the
high water line or bin them,because that mouth breeding does
give them that really goodadvantage of transferring their
eggs later on.
Speaker 2 (17:58):
Yeah, and I guess one of the things that's happening
with these fish is that youwouldn't normally expect to find
tilapia in cooler waters, butthey seem to be able to adapt
and so that adaptation processare we looking at it, taking
years, or actually much quicker,so that they could survive in
much cooler temperatures?
Speaker 1 (18:17):
There's this process called hybrid vigor.
So hybrid vigor is when twodifferent species, they
hybridise, they make offspringand they both take aspects of
the parents and they themselvesbecome better than their parents
.
And because we have severaldifferent types of tilapia
species in Australia, whatthey're concerned about is them
hybridising and becoming coldwater tolerable.
(18:38):
I'm not sure on how fast itcould occur, but just the fact
that it's a problem here and apotential means that it could
become an issue.
Just like the problem with carphybridising and then becoming a
more virulent strain, it's aproblem that we could have with
tilapia as well, and they cansurvive quite low temperatures
already.
So moving further south intothose colder areas, those
temperate areas down south,won't be a problem for them.
Speaker 2 (19:01):
And what about some of our little tiny invasive fish
like gambusia?
Are there a few more of them onthe horizon that might possibly
go into our waterways thatyou've examined?
Speaker 1 (19:12):
Yeah, there are a lot of smaller fish coming through.
We just had Siamese fightingfish established up north, or
the reports of it, in the Darwinarea, and if we look at the
water temperature averagesacross Australia this is
something that I looked at inthe last report I did for the
Department of Agriculture andFisheries they should not be
able to survive anywhere inAustralia, they should not be
able to establish.
(19:32):
But they have.
They've established and they'rebreeding in their thousands and
so we're underprepared forthese smaller fish because we're
overlooking them.
We're thinking about thesebigger predators, like the
tilapia, like the jaguarcichlids, like the peacock bass,
all these bigger ones, butwe're overlooking these smaller
ones that could have more damagebecause they could compete
better with our little nativeslooking for that resource of the
(19:53):
things.
Speaker 2 (19:54):
Yes, our little natives are little, and you know
, I know, up around the Coomaarea we've actually
purpose-built a river for ourlittle stocky galaxids, which
were under threat from fires,and so the thought of all these
other ones coming in, as I say,it does make you tremble a
little when you have looked atthe deep web and looked at the
(20:16):
sorts of fish that people arebuying.
Are people buying them becausethey're pretty, and what's the
level of awareness that thesefish could potentially harm our
native ecosystem?
Or is that sort of not really ajoining the dots exercise?
That's happened yet.
Speaker 1 (20:33):
That biosecurity understanding.
A lot of people don't realisethey have a biosecurity
obligation in Australia to notrelease these and their
understanding of these fishcould become a problem.
There doesn't seem to be thatconnection.
A lot of people feel guiltyabout needing to euthanize their
fish if they become sickly andthere was a study in Canada
because there aren't very manyin Australia on people's
(20:54):
motivations for release, but astudy in Canada that found
people were more likely torelease their fish into a river
because they felt like it wouldbe a good burial place for the
fish rather than putting it inbins and things.
So I don't believe there's thatyet understanding of wow, these
fish can actually do harm toour environment and it's an
educational issue.
Really there's no targeted bigcampaigns throughout Australia.
(21:18):
There's smaller ones and theyseem to be good on some aspect.
But we need that targetedinformation in pet stores,
eco-labelling especially, sothat is providing information to
consumers.
So customers and people likethat before purchase so they
understand the size the fishcould grow to, whether they're
aggressive, how they get on withother different fish, how long
(21:40):
they live as well is a bigproblem.
Some of these fish can live fordecades.
You might not be ready for a15-year commitment with these
fish.
So it's something that isreally lacking in a lot of pet
stores and it's not compulsoryin Australia.
It's a participation style, andone of the things I found as
well in my research because Ilooked at ecolabeling was that a
lot of the information beingput out was incorrect.
(22:01):
So people are saying this fishlives for five years, this fish
lives for seven years, whenactually it can live up to 18.
Speaker 2 (22:08):
Wow, that's a much longer term commitment.
And the other thing that reallystruck me about what you said
there was it's a biosecurityobligation, dead or alive,
because, as you said, with thetilapia for instance, if the
eggs make it, even if the fishis dead.
If the eggs touch water, thenthey're away and presumably if
(22:31):
you flush one of these fish, ifit's dead, into the waterway, if
it's got some sort of disease,it could pass that on.
Speaker 1 (22:39):
They already are.
So we have found well, wehaven't, sorry, I've found
research where diseases fromthings like goldfish and tilapia
are already passing on to ournative fish.
So pathogens, parasites,they're already being passed
along.
And one of the bigger issues wehave is just we have that lack
of pre-invasion informationabout our ecosystems, about our
fish.
(22:59):
What's a native?
What are the native parasitesto these fish here?
What are the food web structure?
We don't understand really apristine environment before the
fish come in.
So we can't really deftlyidentify what's happened, what's
changed.
So it's difficult to kind ofdraw a line of where these
impacts are.
But we are seeing some issuesalready.
So how many more are we notunderstanding because we just
(23:21):
don't understand pre-invasion?
Speaker 2 (23:30):
Yeah, it is a problem for us with things like the
redfin perch, which carries aparticular virus called the EHN
virus that affects Macquarieperch, which is a native fish.
So you're spot on there interms of we're sort of tending
to play catch up because it'ssort of happening and we're
trying to react.
I know with tilapia that we aretrying certainly that this fish
doesn't get into theMurray-Darling Basin.
Can you tell me a bit moreabout the work that you're now
(23:50):
doing with the Murray-DarlingBasin Authority looking at this
particular fish?
Speaker 1 (23:54):
Yes.
So I have been commissioned bythe Murray-Darling Basin
Authority to produce a 10-yearexclusion strategy for them, so
2025 to 2035.
So the plan to try and keeptilapia out of the basin.
We haven't had any close callsor anything.
It's been fantastic in thebasin, really strong education
system to keep them from movingdown.
(24:15):
But we need a new plan.
The last one expired and it'lljust be carried through those
kind of principles.
So targeting things likeeducation is especially
important.
There was a study that came outa few years ago that compared
Queensland to New South Waleseducation understanding around
biosecurity for tilapia andunfortunately the resources for
New South Wales have been quitepoor.
(24:35):
A lot of the information hasgone into Queensland because
that's where tilapia are.
But the issue is, as tilapiamove down, we need to increase
the education down south as well.
So that's a really importantpart of keeping the fish out and
also monitoring and detecting.
So if we do have a fish pop up,we know what to do, we know who
to contact, we know whoseresources are available in the
area and we know what the highrisk catchments, the high risk
(24:58):
rivers and things are.
So we can go and check thoseregularly to make sure they're
not spreading, because most ofthe introductions in Australia
have been deliberate choices bypeople, and that's the issue.
They're making these wrongchoices about, releasing them,
and that's we need to target.
Most of our efforts is keepingthese fish from being moved by
people.
Speaker 2 (25:18):
Yes, I don't know that many realise, but that's
actually how.
We have a number of our specieswhere people have said, oh,
this is a great recreationalfish, I'm going to pop it in my
local stream.
It might be a trout, it mightbe a whole range of other fish
that, yeah, they may befantastic to catch, but they're
not really meant to be in ourwaterways when we're spending so
much time and effort trying tokeep our native fish alive.
(25:40):
So if you were running aneducation campaign, for instance
, who would you be targeting?
Is it wreck fishers?
Is it at the school level?
Is there a particular age group?
What sort of profile is thereof the person that we need to be
talking to?
Speaker 1 (25:57):
You're spot on there that it's the kids and the wreck
fishers.
Kids take their information,they learn home, they teach
their parents.
It's easier to talk to childrenabout it and then they take it
home rather than trying toconvince an adult to change
their ways.
But recreational fishers aswell.
We're not blaming them, ofcourse.
Most of them are doing whatthey need to do.
Most of them are going outthere.
They're fishing in the rightplaces for the right fish.
(26:20):
They're cleaning things beforethey go and coming back for the
right fish.
They're cleaning things beforethey go and coming back, so
they're not transplanting eggsor anything like that.
It's just the few who ruin itfor the many.
It's that saying, but just thatunderstanding that just because
it's a fun fish to fish for inother parts of the world, it's
not right for Australia.
We've got other great nativeswe can be targeting instead.
Or you can target things likecarp and redfin perch to help
(26:41):
remove them from our environmentand do your part.
But yes, it's the school kidsand the recreational fishers
that really need thatinformation.
And part of the educationoutreach program I did for the
Murray-Darling Basin Authoritytwo years ago was part of
recreational fisher targetedprogram on Facebook and what it
(27:01):
was was comparing the juveniletilapia with some juvenile
natives, and some peoplecouldn't see the difference.
They couldn't identify whichwas a tilapia and which was a
native.
And so there is that level ofunderstanding that we need to
improve, because there's been alot of education on the adults.
We all know what a big adulttilapia looks like.
They're big and they're blackand red.
They've got those sharp, thinlooking things, large lips, but
(27:24):
it's the juveniles, because theydo look similar to some of our
natives.
So it's that kind of level ofunderstanding we need to
increase too.
Speaker 2 (27:30):
And I think also I know that I found people
actually want to learn and theywant to understand.
So when you're actually sayingto someone, we want to teach you
how to identify native andnon-native fish, that's a much
better approach than saying weneed to let you know why you
must not do anything if you seethis fish, which is a much more
heavy-handed approach.
(27:51):
So had you looked overseas atall at campaigns where other
countries have tried to raiseawareness about invasive fish?
Are there other models fromoverseas we should be looking at
?
Speaker 1 (28:04):
There are a lot of campaigns and things, and a lot
of them seem to bemilitary-based, so that not
military as in the United StatesArmy or whatever, but more so
military messaging so it's yourresponsibility to fight this war
on fish, and that's just notsomething that really resonates
with a lot of Australians.
So it's a different type ofviewpoint here that we need to
(28:30):
be looking at.
It's the compassion side, it'sthe bandwagon.
We're all a community, we'reall together.
That's how we are done here.
We stick together.
So it is a bit different fromoverseas, but there's not many
tilapia-specific campaignsoverseas either.
They're really focused on othernon-natives as well.
So it's difficult to kind ofborrow from overseas.
It's really we're starting fromthe roots for some of these
things.
Speaker 2 (28:49):
But what I love about that insight is that, yeah,
I've never found that a militaryapproach works in Australia.
We do not respond to that, butwe do respond well to we're all
part of the same community.
Let's work on this together.
It's a much more inclusive,non-blaming approach.
Rather than you're the problem,make people part of the
solution.
Speaker 1 (29:08):
Yeah, because for many, they're not the reason
that it's happening.
It's just a few people who haveruined it for many, and so we
do need to unite to help removethis issue from Australia.
Speaker 2 (29:19):
And often those people that have released them
have done so unintentionally,not realising the impact that
releasing the fish have.
So we've talked abouteco-labelling and we've talked
about really raising awarenessof people prior to buying these
fish about the fact that it's alonger term commitment and that
there's a biosecurity issue aswell.
(29:39):
Is there other things that weneed to be doing in terms of
this threat that ornamental fishmight pose?
Speaker 1 (29:49):
The switch to natives would be a really great push.
I know some aquarium shops areactually having native displays
now, rather than having theseornamental ones, because we do
have some really beautifulnatives here, the rainbow fish.
They're called rainbow fish fora reason.
Yes, they are beautiful.
Speaker 2 (30:06):
Yes, yeah.
Speaker 1 (30:07):
And then our smaller ones as well.
But even things like barramundi.
You can get a black and whitepanda barramundi.
You know they do get larger,but how beautiful are those?
And golden about goldenbarramundi as well.
So we do have some beautifulnatives.
So, switching our thinking fromwe need to have these flashy
fish from overseas and goingwell, what about some natives?
The Angfa Society in Australia,which is the Australian and New
(30:30):
Guinea Fisheries FishersAssociation.
They have an education campaignin school, a few schools where
they go in, and they actuallyhave the kids raise some natives
.
The kids understand aconservation effort, they're
seeing what kind of natives are,and so it's a really great
thing to do.
So rather than raising agoldfish at home with your kids,
why not choose a?
Speaker 2 (30:48):
native.
Yeah, that's a great idea, andI know that my local aquarium
does have some natives.
I have seen some southern pygmyperch in there.
I've seen a few Murray cod andso it's nice to see them in
there, just providing that theylook that Murray Cod could
actually get quite big.
It's not really for the fishtank at home.
Speaker 1 (31:06):
Yes, yeah, and that eco-labelling, then, is really
important to have theinformation.
So if you do buy a fish withouttalking to someone first,
you're prepared, you're nothaving to go home and do all
this research after you'vebought the fish, you go in, you
can make your choice.
It's an informed choice, justlike when we're buying anything
else.
So smoking, you've got thethings on the packets, nutrition
labels and things.
Understanding, being informed,making those informed choices is
(31:28):
really important.
Speaker 2 (31:29):
Yeah, yeah.
So you started off in researchasking lots of questions and I
can tell you've got a veryinquiring mind and you've ended
up in fish.
What's been a really memorablemoment for you in your career so
far and you're only juststarting out, really but what's
been really memorable for you?
Speaker 1 (31:48):
All the conferences.
I have to say it's beenfantastic to connect with all
the other fishy people.
I had a great time at theNative Fish Forum talking about
the ornamental field, because itfelt like something that people
didn't really understand was aproblem, particularly for the
Murray-Darling Basin area andthings and there was a lot of
people that came and said, wow,we didn't realise that this was
an issue.
So it's, the conversations withpeople has been really shining.
(32:09):
I've been to about 20conferences already in my short
career and it's been always sogreat to see people go, wow,
this is something we need toconsider.
This is something that we needto put more research into to
understand better.
Speaker 2 (32:26):
And do you have a soft spot for a native fish in
Australia?
Speaker 1 (32:31):
Oh, I have to say, the Bozeman's rainbows, the
lovely blue and yellow, yeah,beautiful, beautiful fish, and
they're a plucky little fish aswell.
All the rainbows, they all haveconservation statuses, but
they're still plodding alongquite well, most of them.
Speaker 2 (32:46):
So the rainbow fish for me, oh great.
Well, we'll try and find apicture of that to put along
with the show notes.
So we're getting to the end ofour conversation, which I've
thoroughly enjoyed.
Thank you so much.
I want to ask you threequestions that we ask everybody.
Do you have a favourite riveror a waterway or body of water?
Speaker 1 (33:06):
Oh, I'd have to say Narin Lakes.
It's out near Lightning Bridge,so the northern New South Wales
and that was where I was reallyon country, really doing that
work.
It was a plant-based one, butthe number of animals I saw and
the education and learning I gotfrom the Aboriginal range is
about just even the stars inthat area, learning about the
Milky Way, just being there, itjust felt so connected.
(33:29):
So the Narren Lakes area isdefinitely a favourite part of
Australia for me, but there area lot.
It's hard to choose one, isn'tit?
Speaker 2 (33:37):
It is because we're so blessed with so many
different river environmentshere as well.
And so this leads on to my nextone, which is where do you feel
most connected to country andto nature?
And it sounded like NarrenLakes was one of those places.
Speaker 1 (33:49):
Yes, yeah, it's been a little while since I've been
out there so I'd love to go backwhen it's in flood so I can see
the fish.
But just in anywhere outside,really in the just getting out
in a park, I'm down in theNepean River area.
Beautiful down there along therivers, just even if it's not in
a river, next to a river isgreat.
Hearing that getting out ontothe land.
Speaker 2 (34:10):
Fantastic.
And finally, Mariah, what isdriving you to do what you do?
Good question.
Speaker 1 (34:15):
I think it's curiosity if I can say that.
Speaker 2 (34:18):
You certainly can.
Speaker 1 (34:20):
Just finding out, just seeing.
Why is that like that?
Why are we having this?
What is there?
Speaker 2 (34:28):
It's just the why I think you remind me so much of
my little brother.
I did a lot of sort of care forhim.
I'm nine years older than himand at one stage he just kept
saying but why, but, why, butwhy?
Thank you so much for spendingsome time with us.
I know that our listeners aregoing to really enjoy this
podcast episode and, for anyoneinterested, we'll put some show
(34:51):
notes to go along with Mariah'stalk this afternoon and you can
look up and find out even moreabout the work she's doing.
So thank you, mariah, reallyappreciate having you on the
show and we will keep in touch.
Thank you, mariah.
I really appreciate having youon the show and we will keep in
touch, thank you.
Thank you.
You can subscribe to Take Me tothe River wherever you get your
(35:11):
podcasts.
Visit arrcau forward slashpodcast to learn more.
That's arrcau forward slashpodcast.
We acknowledge and respectAboriginal and Torres Strait
Islander peoples as thetraditional and continuing
custodians of the country andthe rivers on which we live,
(35:33):
learn, love and play.
We respect and learn fromelders, past, present and
emerging, valuing theirknowledge, insights, cultures
and connections to the waterwayswe all love and care for.
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