Invasive Hoplosternum

[Silurus]

Duxbury, C, J Holland & M Pluchino, 2010. Experimental evaluation of the impacts of the invasive catfish Hoplosternum littorale (Hancock, 1828) on aquatic macroinvertebrates. Aquatic Invasions 5: 97–102.

[Suckermouth]

I didn't even know we had Hoplos in the states. Dang. Thanks for the link, this one is getting passed on.

[Bas Pels]

So sad

Here, on the European continent they are almost impossible to get, and there they are regarded as pests

[MatsP]

So sad

Here, on the European continent they are almost impossible to get, and there they are regarded as pests

They have some at Pier (or did a few weeks ago, at least - and given the number of them, I doubt that they are gone).

--
Mats

[Bas Pels]

As many in Brittan say, the UK is not on the continent.

I heard a wholeseller got 100 of them, a fortnight back. As someone on a dutchforum had realized H littorale would fit best in his tank, he ordered 8. A day or two later

However, the fish were all sold. Another forum member could arrange things, but still, selling some 90 H littorale in a week is quite impressive, I think

I hope they import them more often after this experience

[bronzefry]

Near my sister's new place...

[Shane]

Near my sister's new place...

Then you have to get her to make cascadura curry. It is delicious and a part of the folklore for the area.

Here is the recipe

http://www.simplytrinicooking.com/2008/ ... pling.html

"Writing this post brings back some childhood memories. As a boy, I could remember going to San Juan market with my father early in the morning and I would see the different stalls some with vegetables, others with provision and some with all types of fish. Of course, there would always be an Indian person with some strange prehistoric looking fish that don’t seem to die easily because they would still be jumping up in the box. Later on I learnt that they were called “Cascadoo”. And the only way you could really enjoy this fish was in a good curry with either rice or dumplings.
Here in Trinidad the Cascadoo (Cascadura or Hoplosternum littorale) also has a legend attached to it. It goes like this...”Anyone who eats the cascadura, wheresoever they may wander, shall end their days in Trinidad”. Well I can certainly say that I will surely be ending my days in Trinidad because I have eaten this fish a few times already . Even writing this, brings back memories of reading Trinidad born author Samuel Selvon’s stories “Those who eat the Cascadura” (1972) and “Johnson and the Cascadura” (1957) that has immortalised the legend for ages to come. Strange though, it is only now that I have truly come to appreciate all those long hours, doing Literature at Secondary school, studying the local writers such as Samuel Selvon, Earl Lovelace, Michael Anthony and V.S Naipaul.

Other names for the cascadura are the Brown Hoplo or the armoured catfish. For more information you can visit these links below."

and you can get the fish for free!

-Shane

[kim m]

So sad

Here, on the European continent they are almost impossible to get, and there they are regarded as pests

They have some at Pier (or did a few weeks ago, at least - and given the number of them, I doubt that they are gone).

--
Mats

I would love to have taken some home, but they would take up too much space in tha suitcase...

[bronzefry]

Thanks, Shane. Free food is always good and a change from I.punctatus and friends. I just need to find time to get down there! I also want to be sure to coordinate w/Fish and Game to see the Manatees and Loricariids.
Amanda

[Silurus]

I just need to find time to get down there! I also want to be sure to coordinate w/Fish and Game to see the Manatees and Loricariids.

I take it you mean the loricariids grazing on the manatees?

[sidguppy]

wow
talk about impact on an already endangered species.....

however, on the littorale's; I can agree on them being tasty.
have eaten them (although not in Trinidad, sadly) and they taste very good.

I think -speculating here- that the impact on the wildlife of H littorale will be far less than of Pterygoplichthys

according to the article the catfish tends to occur mostly where there are "artificial surfaces" in the water and feed on chironomids (bloodworms and related).
artificial substrates can be translated as litter/trash/garbages and chironomids are a marker species for heavily polluted water

the scientists worry that in time the predation of chironomids will screw up the tables of marker species used to describe the different stafia of pollution; but I disagree
it's still useful
1: the littorale itself will be a marker species for pollution since it obviously thrives where man has built and/or littered the waters
2: it's not the marker species but the pollution itself that's the rootcause here

the solution is simple, although the big companies probably will try to smokescreen it: do not pollute in the first place.

then there's no such thing needed as marker species at all.

[apistomaster]

Eutrophic can be seen to exist on a continuum and further divided between natural still waters and artificially polluted still waters.
In natural conditions a lake becomes eutrophic near the end of it's life in geological terms.
Many of the finest trophy trout lakes are eutrophic, extremely rich in Chironomids by % of biomass but are not considered polluted waters.
Healthy trout and polluted water are incompatible.
It is no surprise that invasive Hoplosternum might thrive in a polluted body of water.

[grokefish]

I observe these things with an open and somewhat different view to others.
These 'invasive species' have clearly been introduced by humans to these environments and therefore are classed as 'alien'.
This view sort of places human beings 'outside of nature' as if we were a species from another planet.
My opinion is that if we assume that humans have evolved on this planet as we are led to believe then we are part of nature and our actions are merely a result of evolution continuing but along a 'different path' to what we assume/believe it should go.
But who are we really to decide what nature/evolution has planned for life?
Why do we despair at a species 'introduced by humans' get a foothold in an ecosystem they 'don't belong'?
These hoplosternum have been equipped by evolution/nature to thrive in such an environment whether it be in the amazon or in Florida.
This is just another path that evolution has gone down, a more recent path development in the history of life on this planet but nevertheless a direct result of evolution/nature and all that has gone before us and will continue to be after us.
All this shit will sort itself out one day, probably after we are long gone.
Humans should stop being so vain and accept the fact that we are part of the bigger picture of life and our actions are a result of human nature and therefore part of nature itself.

[apistomaster]

Matt,
While I appreciate where your philosophical POV comes from, it has occurred to me too, that perhaps in the larger scheme of things mankind's spreading species isolated by thousands of miles and sometimes millions of years of separation just essentially is the result of being human as in part of the natural world. I can't accept that it is "natural" or desirable on any level. Human beings transcended the limits of the natural world through culture and technology but that didn't give us the right to repopulate the continents with alien species.
We are stuck with the results of our actions but there has never been one truly desirable outcome from human beings introducing species to any environment in which they are aliens.
I think Small Mouth Bass make great fly fishing quarry and because of some proactive groups introduced them to the Columbia River system over a century ago and they have become naturalized, I can enjoy fishing for them merely minutes from my home. I would be much happier to be fishing and catching native Cutthroat and Sea Run Rainbow trout that have been largely displaced by these introduced species. These are only relocated native North American fish from the east of the Rocky Mountains to the West side of the range. But alien species nevertheless. It was the construction of hydroelectric dams and the commitant creation of large impoundments which truly drove the Salmonids to the brink of extinction and encouraged the prosperity of the introduced Bass but I don't appreciate either man induced change from the previous natural state.
I am part of the minority who writes to their Congressional representatives to support the removal of every damned dam on the Columbia River and its tributaries to permit the restoration of the rivers to their natural state which would benefit the remaining surviving native species greatly. It is a fool's errand but not everyone is favorably disposed to all this "development."
Heck, I would prefer we construct a few nuclear power plants for every dam removed and deal with the problems associated with nuclear waste disposition. A wild and free river is a wondrous thing and we are no strangers to nuclear development. The Hanford Nuclear reservation along the Washington side of the main Columbia River was the first and primary source of the plutonium used to make our nuclear weapons arsenal.

[Bas Pels]

starting from another point of view, if we would humans in the term 'nature', nature would come down to everything - and therefore be meaningless

The current way of reasoning - it's natural, unless done by humans - at least provides a meaning to the wordt 'natural'.

I do agree, however, that where conservationists focus on the rare species, which are due to become extinct anyway, and ignlore all the species which are able to adapt, thet theyt are wrong.

We have a group of birds in the Netherlands, I think they are named herring in English, in a grey species (bleu herring) but there is also a prownish one (purple). The latter is rare, the former is common. So conservationalist ignore the bleu herring and focus on the purple ones. Stupid, I'd say

[racoll]

Grokefish, you are absolutely correct in the long, long-term, and of course, humans are but a blip in the course of evolution, but we as a society live very much in the short term, and actions such as introducing alien species is partly driving the dramatic reduction in biodiversity we see today.

This biodiversity loss is serious, and will have a huge impact on human life here and now, in terms of lost ecosystem services.

The planet will be okay, but will we?

[grokefish]

In my above post I am pointing out that human introduction of 'alien/invasive species is just a fact and part of the natural scheme of things, not that I like the idea.

I like the idea of things being in their 'natural environment', which is a bit of a farcical statement, as the natural world covers the whole planet so it's fair game to any species HOWEVER they get there.
How do we know that the hoplosternum were never meant to reach Florida?
Clearly the evidence shows that they were in fact meant to.
They have just not reached there by what we perceive as 'natural means'.
I will be very sad when the last manatee dies, I am very sad when any species becomes extinct, this means I am sad about three times every hour, but like the idiot guy in Jurassic park says 'Life will find a way'

Larry I could not agree more.

Bas,
"The current way of reasoning - it's natural, unless done by humans - at least provides a meaning to the word 'natural' "

This separation between our species and nature IS the root cause of ALL environmental problems.
We have distanced ourselves from nature and lost that link.
This makes it easier for us to separate the damage we do to the biosphere from ourselves and absolve our guilt.
It is as if the majority are watching this destruction in a comfortable chair in their sitting room on another planet.

The sooner the human species as a whole reconnects with nature, and I don't mean that in the hippy sense, and realizes that we are an integral part of this thing we call nature the sooner the masses will realize that we ARE damaging nature and by default hurting ourselves.

We are like twin boys playing hide and seek in a garden with a green house.
One is inside the green house looking at all the beautiful plants and smelling the loverly flowers.
The other is outside bored, he and his brother have become separated whilst playing hide and seek and is now looking for something to do.
The one on the outside is in the current state of the human mind, he's decided to throw rocks at the green house for some short term relief from his boredom and delighting at the shattering glass, he's never had so much fun in his life!.
To his brother this is the most terrifying ordeal that he has ever been through, the glass is shattering and bits of glass and rocks are hitting him from all angles.
The boy on the outside continues throwing rocks, giggling and laughing at all the fun he is having, oblivious to his brother inside, the smashing glass drowning out his cries for help..
When all the glass is broken the boy outside moves in for a closer look at the result of this fun game and finds his twin lying in a pool of his blood all battered and busted.
He now realizes what he has been doing but it is too late.

We need to be rid of the SEPARATION between ourselves and 'nature' which includes us, the separation is all mental.
How else will we survive to see the Florida hoplosternum evolve into a different species to that which remains in the Amazon.

Rupert, I doubt very much that we will be here or if we are it will be a very different species that the few who survive evolve to and hopefully that species will have either evolved into a species with a better respect for their world and a good memory or the human race will have de-volved(?) to resemble the more 'primitive' members of the human race that survive now (Primitive-As in more like the ancestors, rather than as in the usual derogatory use of the word) .

[bronzefry]

Yes, Silurus. That article.
Amanda

[crkinney]

This spring I happend on to a drainage ditch slap full of hoplos ,I diped out nets full of them feeding them to the birds I keep three for my fish tank they will eat almost any thing I put in the tank even raw chicken
This was in central Fl. in the Haw creek area right out side of Cody corner Fl.
I have also caught Plecos in that creek

[apistomaster]

What I don't "get" is why do we always introduce plain, brown ugly species?
English Sparrows. Plecos, Hoplos, brown tree snakes, Bufo marinus toads and rabbits to name a few?
It would nice if we would introduce a few more attractive alien species like Hypancistrus zebra but examples of that are very rare in the history of alien species introductions. Maybe some of the parrots or parakeet types of birds are the few examples of the exceptions. I know they can become a pest, but are more colorful pests.
Nothing makes everyone happy. The reintroduction of Grizzly Bears and Wolves here in the Northern Rockies is not popular and in barely more than a decade after being introduced back into the woods of Northern Idaho, we have begun allowing wolf hunting. In the interest of full disclosure, I did not fish Duck Creek in Yellowstone National Park because the parking lot access point to this stream has "Beware of Grizzly Bears" warning signs prominently posted. There had been several Grizzly Bear attacks of people that year in the Park. No other fishermen were fishing Duck Creek to spread the risk or have any safety of numbers. A Grizzly Bear attack is always really grisly.

[Suckermouth]

What I don't "get" is why do we always introduce plain, brown ugly species?
English Sparrows. plecos, Hoplos, brown tree snakes, Bufo marinus toads and rabbits to name a few?
It would nice if we would introduce a few more attractive alien species like Hypancistrus zebra but examples of that are very rare in the history of alien species introductions. Maybe some of the parrots or parakeet types of birds are the few examples of the exceptions. I know they can become a pest, but are more colorful pests.
Nothing makes everyone happy. The reintroduction of Grizzly Bears and Wolves here in the Northern Rockies is not popular and in barely more than a decade after being introduced back into the woods of Northern Idaho, we have begun allowing wolf hunting. In the interest of full disclosure, I did not fish Duck Creek in Yellowstone National Park because the parking lot access point to this stream has "Beware of Grizzly Bears" warning signs prominently posted. There had been several Grizzly Bear attacks of people that year in the Park. No other fishermen were fishing Duck Creek to spread the risk or have any safety of numbers. A Grizzly Bear attack is always really grisly.

There are a few things that correlate with success of introduction. One of the primary factors is that the "propagule pressure" is high, that is that it is introduced often. This is only possible with common fish. Certain other factors depend on the biology of the organism, such as wide tolerance for conditions as well as high reproductive output. On the other hand, lionfish have been introduced into the Atlantic and are fairly attractive, but again, this is one case compared to the many dozens of other introduced fish species.

[apistomaster]

Hi Milton,
I posed a rhetorical, tongue in cheek question.
I understand that species which are generalists tend to be the most successful invasive species.
In most cases these species will be rather nondescript. If they stand out then the pioneering group will have a lower chance of surviving long enough to reproduce.
The successful establishment of the Lion fish, Pterois volitans seems atypical yet their brilliant colors actually do make good camouflage in the sea. They are also much better armed than most invasive species making them difficult prey.

[Suckermouth]

Haha, I should've been able to see that it was rhetorical.

[apistomaster]

Ha, ha, You sometimes have to read between the lines to tell when I am being serious or not.
I am too serious most of the time but flippant at other times.

[crkinney]

It must be that chain of life thing .The bright colored critters get ate to fast .Really if you want exoitics go to dade county fl if it lives in south america it live there in the cannals and ditches .Everything from pythons to snakeheaded fish ,peacock bass and oscars they got them all .
back to the chain remember the fisherman eats the fish the grizz eats the fisherman and poops in the creek and the fish eat the poop COMPLETE CHAIN

[apistomaster]

"Snip", back to the chain remember the fisherman eats the fish the grizz eats the fisherman and poops in the creek and the fish eat the poop COMPLETE CHAIN

That thought never eluded me. Indeed, I am just averse to being part of that chain.
By both personal inclination and Park regulations, one is supposed to catch and release wild Trout(except Lake Trout) in Yellowstone. That way the food chain remains a closed loop.
A little known fact is that all Trout except the native Yellowstone Spotted Cutthroat Trout were introduced.
In fact, most of the streams never had any Trout except the Yellowstone River system which includes the largest lake in the Park, Yellowstone Lake.
The Rainbow, Brown and Lake Trout are introduced species to the waters in the park. They have been granted a special dispensation to be considered wild Trout to retain the high revenue value of the fly fishing economy to the area. We humans are very ambivalent in our attitudes about introducing non-native species into new environments. Oscars and Peacock Bass are legal game fish in Florida and there are limits on their harvest.

[crkinney]

Todays news paper stated that the chain in still working ,some poor guy got his self ate by GRIZZ out west.
mo poop