# Interesting observations on spread of Tilapia



## Barrabundy (Sep 29, 2008)

This appeared in our local paper today. There are some interesting observations by a seafood business on the spread of this noxious pest.


----------



## Jords (Jun 22, 2008)

hey mate what paper was that? I'm doing a university assignment on the impact of tilapia etc, I think that would be an interesting thing to mention!


----------



## Barrabundy (Sep 29, 2008)

There's been a constant pumpkin soup coloured flush since about November and it's still going.


----------



## redman (Jun 5, 2008)

Jords said:


> hey mate what paper was that? I'm doing a university assignment on the impact of tilapia etc, I think that would be an interesting thing to mention!


Was "The Advocate" in Ayr (North Queensland).

It mentions their is not much fresh where old pro nets but I suspect they have been flushed from the Fresh.

Having said that I have caught a rather large one in saltwater at Three Mile Creek, Palleranda when not flooding.

Only bright spot is they are feeding local fish populations!


----------



## Barrabundy (Sep 29, 2008)

Old mate down the road reckons they taste ok but I've never tried one. One thing's for sure, it's damn easy to get half a dozen kilo sized ones with one throw of the cast net in the right spot.


----------



## maddog (Jan 14, 2008)

Tilapia is sold at heaps of restaurants in the US. i couldn't believe how common it was last time I was over there


----------



## anselmo (Aug 26, 2008)

Tilapia is delicious
Possibly one of the best eating fish around whether from fresh or saltwater
They are also a very good sportfish when they reach a decent size (0.5kg up)

I used to catch them in both the fresh and salt in the North Pine River 15 years ago (tilapia infestation is not a new problem )
Like redfin they will overpopulate and stunt
They also have a habit of nipping fins off other fish

Incredibly in QLD it's illegal to possess them DEAD or alive: http://www.dpi.qld.gov.au/28_13879.htm
"It is unlawful to possess noxious fish alive or dead or to use them as bait."

Given how easy it would be to control (note: control not eradicate) their population by allowing fishermen to keep and eat them
It would make sense for the legislation to be altered to say ALL tilapia irrespective of size must be killed, and anyone found in possession of a live fish will be yada yada

Barrabundy, its illegal to eat fish caught in a cast net from memory
its also illegal to have tilapia in your possession 
screw that i say, catch every last one of them in your net and eat them all

steam them them over soy sauce, ginger, chilli, garlic and asian greens and serve on rice
yum yum

Nick


----------



## Barrabundy (Sep 29, 2008)

Anselmo, I didn't know that you can't eat fish caught in a castnet. It's illegal to use them in freshwater or "closed" or non-tidal waters. Are you sure about not being able to eat fish caught by castnet?.....I may or may not have done exactly that in the past :shock:


----------



## anselmo (Aug 26, 2008)

Barrabundy said:


> Anselmo, I didn't know that you can't eat fish caught in a castnet. It's illegal to use them in freshwater or "closed" or non-tidal waters. Are you sure about not being able to eat fish caught by castnet?.....I may or may not have done exactly that in the past :shock:


I've just checked and I can't see it anywhere

but I am pretty sure that _intent_is for the castnet is only allowed to be used for the purposes of gathering bait
(not sure where prawns fit in here ...)

It may be one of those grey areas where the intent of the legislation doesn't actually meet the application of the law the legislation produces
... what a surprise ...

I would say that if a fisheries officer saw you _intentionally_ cast netting and hauling in bream, whiting or barra you may get in some hot water
but, if you were targetting bait fish and pulled in some Tilapia they would probably say kill them and dispose of them 
(though apparently you are supposed to do this without having them in your possession :lol

I do know that when I was 13 a friend was stopped by a fisheries officer and told to release a legal sized luderick he caught in a cast net ...


----------



## Barrabundy (Sep 29, 2008)

leftieant said:


> Back to the OP, I think the assertion of the article is incorrect. What they are trying to imply is that tilapia are taking over in fresh and salt water, and are going to be a threat to saltwater fish.
> 
> There is a much more feasible explanation, that being that the tilapia are being flushed into salt and then predated by bigger fish.
> 
> When you hear hoofbeats, don't look for zebras.


Yeah, there is an element of "beat up" about it. What it was a tually saying was how much of a food source they are for native fish.

The guy being quoted is described as a "retailer" if I recall correctly and is mixed up with the fish restocking....may e it's more "donate more, help more, restock more" than anything else. I must say the only ones I've seen in saltwater have been as desperately close to the fresh as possible after being flushed out.


----------



## Junglefisher (Jun 2, 2008)

There is a Tilapia that can live in salt water (Tilapia mariae) but it does not seem to be as much as a problem as the freshwater one (Oreochromis mossambicus).


----------



## redman (Jun 5, 2008)

leftieant said:


> Back to the OP, I think the assertion of the article is incorrect. What they are trying to imply is that tilapia are taking over in fresh and salt water, and are going to be a threat to saltwater fish.
> 
> There is a much more feasible explanation, that being that the tilapia are being flushed into salt and then predated by bigger fish.
> 
> When you hear hoofbeats, don't look for zebras.


Nail on the head.


----------



## redman (Jun 5, 2008)

anselmo said:


> Tilapia is delicious
> Possibly one of the best eating fish around whether from fresh or saltwater
> They are also a very good sportfish when they reach a decent size (0.5kg up)
> 
> ...


Now don't quote me on this BUT I believe the rationale for such a law is so that they are not turned into a commodity and stocked in Dams etc which will assist their spread.

Personally I believe it is at the stage where it will not do any more real damage. Outlaw stocking on Dams but many have them in any event so would be hard to Police. A law which is redundant and irrelevant in current corcumstances.

THey are so widespread only real help to control would be to have people actively target them as a tablefish/sportfish.

They support many people in Africa and are in some villages a primary source of food/income.

Open them up to same pressures as other fish - right now they are a protected species in essence as no-one will target them.

THey do put up a god fight as well - hooked two the other week when barra fishing and thought they were Jacks!


----------



## Rose (Jan 30, 2006)

xxxxxxxxxxxxxxxx


----------



## Barrabundy (Sep 29, 2008)

It's an interesting topic which I don't really understand but I've had my preconceptions on saltwater organisms surviving in fresh and vice-versa seriouslyt challenged in recent years.

A pro fisherman told me that he washes live crabs carefully in freshwater so they don't ingest any. This way he keeps a larger number alive to make a trip to market worthwhile. I was under the impression that crabs would die very quickly in freshwater. I know of places on properties where the upper reaches of creeks and swamps are dammed to stop saltwater intrusion. These dams break during the wet season and areas that once were tidal become tidal once again, for many months, until the dams are rebuilt. I've seen crabs which have lived in 100% freshwater for 6 months.

Many years ago I had a muddie escape on me during the night and in the morning tracked it down the dirt driveway, into a drain which drained a freshwater lagoon. Quite a few years later I was speaking to the neighbour and the subject of the missing crab came up....."so THAT'S how it got there?"....He'd found a MASSIVE mudcrab covered in green slime on the edge of the lagoon, still alive, and was gobsmacked as to what it was doing there. We couldn't really work out how long it would have been there....or whether it was the same crab....but it would have been at least a year if not a few.

I also come across flathead, whiting, javelin, diamond scale mullet, giant herring trapped in freshwater and living there for many months.

The life cycle of marine organisms is definitely intersting!


----------



## anselmo (Aug 26, 2008)

Junglefisher said:


> There is a Tilapia that can live in salt water (Tilapia mariae) but it does not seem to be as much as a problem as the freshwater one (Oreochromis mossambicus).


Craig

Both tilapia can and do live in saltwater
As far back as 1990 a Cairns newspaper ran a story on how tilapia had spread from one creek into a whole system by moving into SW and colonising up and down the cost form the original hotspot

Nick


----------



## anselmo (Aug 26, 2008)

redman said:


> anselmo said:
> 
> 
> > Tilapia is delicious
> ...


totally agree with you on all points Geoff
next time you hook one, kill it and eat it and report back to us
if its of a decent size, you won't be disappointed


----------



## Junglefisher (Jun 2, 2008)

I've been known to ignore the rules and eat them. 
For a freshwater fish, they're fine.
They make good Thai Fish Balls too.
Not too hard to fillet either.
And makes you feel good about taking them by knowing they are a pest species.


----------



## anselmo (Aug 26, 2008)

Junglefisher said:


> I've been known to ignore the rules and eat them.
> For a freshwater fish, they're fine.
> They make good Thai Fish Balls too.
> Not too hard to fillet either.
> And makes you feel good about taking them by knowing they are a pest species.


The SW ones are even better eating
I like (liked) them better than bream (bigger), whiting (bigger, less bones) and flathead (bigger than the ones I caught!)
they are quite an attractive fish as well, subtle greens, purples, mauves and greys
easy to handle, no sharp spines

even from muddy water they taste good (unlike bream, carp etc)


----------



## killer (Dec 22, 2010)

Tilapia, a good eating fish & a great fighter, I used to catch them in the upper reachers of sumerset dam around the sticks in the stanley river along with big yellowbelly, silver perch & bass, as they're a pest i used to take them home & eat them, i didn't know that it was illegal to have them in your possesion as you are supposed to dispose of them & not throw them back in, so its a bit of a catch 22 situation if you are pulled up by fisheries i guess. it didn't happen to me, i just ate them :lol: .


----------



## Barrabundy (Sep 29, 2008)

Available as frozen whole fish from Tweed Heads for $9.90/kg!


----------



## kiwipea (Jun 17, 2008)

Barrabundy said:


> Available as frozen whole fish from Tweed Heads for $9.90/kg!


Ok, I buy a fish from Tweed Heads, Then drive the few km up to have a fish lunch with my son who lives across the border on the the Gold Coast.
Stating the obvious, but guess I'm breaking the law by having a prohibited fish in Qld. All a bit stupid in my book.

Local fish shop here on Central Coast NSW sells whole Tilapia (from Taiwan) $7.99 kg

kp


----------



## Barrabundy (Sep 29, 2008)

Possibly because it's imported as a good product through proper channels you'd be ok....providing you could track it back to the shop.


----------



## anselmo (Aug 26, 2008)

liam8227 said:


> I spoke to a fisheries inspector last week who shared the common belief that it is a stupid law and that rec fishers should be targeting them.
> 
> On the salt/fresh water living I think it is a case that salt and fresh water fish have different densities in their tissues. Saltwater fish also have highly active kidneys to get the salt out. The water is denser than their flesh so they drink to take in moisture. Whereas the opposite is true for freshwater fish. When you look at your sounder (expensive one!) after a flood you can pick up the areas where the water is saltier (usually on the bottom but temperatures can muck things around) and where it is fresh. The areas are quite clearly delineated and don't just mix to form one solution. The two types of fish may be found in the salty or fresh areas of the estuary. Incidentally it is also a a very handy way of working out where the fish are. Many salt water fish may adapt to fresh (fish like bass are salt water fish that have adapted permanently to fresh the Saratoga is one of the only true fresh water fish in Aus) because their bodies are able to cope with the less dense water and the lack of salt however fresh water fish will struggle with metabolising the salt. I may not have this 100% right but this is how I understand the issue!


liam

your understanding of biology is correct
there are however fish that can and do live - thats live as opposed to travel just to breed e.g. pacific salmon - in both pure freshwater and pure saltwater (and mixed ratios in between) - diadromous is the correct term for fish that _can_ travel to _breed_
I can't remember if there is a term for fish that just live in both

barramundi are a prime example, but also bass, tarpon and mullet 
all the above are strictly speaking catadromous in that they _must_ migrate to SW to successfully breed
however they all can and do live successfully in freshwater - sometimes not ever breeding or migrating to breed

you can also add tilapia to that list ;-) - except that tilapia breed in FW - they are not considered anadromous as they live in FW as well as breeding in FW
true anadromous fish only move to FW to breed i.e. atlantic and pacific salmon
they will be washed out (as in the carp example at the murray mouth above)
but given time they can also adapt and live in SW
which is why they are a threat - they can expand their range and colonise systems other than those they were released into

Tilapia _could_ be described as an amphidromous species i.e one that moves between estuaries and coastal rivers and streams, usually associated with the search for food and/or refuge rather than the need to reproduce. Amphidromous fish are usually defined as one that can spawn in either freshwater or in a marine environment. I'm not sure if tilapia can breed successfully in a brackish or marine environment though - I don't think so

see also: http://en.wikipedia.org/wiki/Tilapia_as_exotic_species

I think I'd just classify them as a pest - albeit a fun and tasty one

Nick


----------

