Invasive Species [Archive] - Fly Fishing Forum

: Invasive Species

01-03-2006, 02:13 PM
One of the greatest threats to our fisheries in the Great Lakes is the introduction of "Alien" or invasive species. Zebra Mussels, Sea Lampreys, Purple Loosestrife and Gobies are just a few of the over 140 non-native species that have been introduced in and around the Great Lakes.

They not only affect our fishing, they take a bite out of our wallets as well. I recently learned that about $15 million a year is spent by the federal government to fight Sea Lampreys alone. This amount of money is spent every year and will continue to be spent every year for the foreseeable future. And it comes out of our taxes! And thatís not the end of it. The U.S. Fish and Wildlife Service estimates that Alien species will cost the US about $5 billion dollars over the next decade in economic losses.

I am interested in peopleís thoughts on this problem. What do you think is the greatest threat to our fisheries? What is the best way to combat the problem? Should ocean going vessels (one of the primary sources of the problem) be more strictly regulated? Let me know what you think of the problem


01-03-2006, 03:04 PM
Are you advocating irradicating the aliens O. Mykiss and S. Trutta, etc. and restoring S. Salar and S. Namaycush? I'm all for it.
Bill :lildevl:

01-03-2006, 03:12 PM

If S. Salar and S. Namaycush could be restored to there historic levels I would be all over that!


P.S. Donít forget S. Fontinalis! :smokin:

01-03-2006, 08:46 PM
speaking of reintroducing native species, has anyone heard more about the attempts at reintroducing atlantic salmon to the great lakes? I know NY state talks about atlantic salmon in lake Ontario, but I never hear of anyone fishing for them?
I understand there are problems with reproduction due to a lack of bioavailable thiamine (thanks to alewives) as well as the fact that the native atlantic salmon populations have since been overfished beyond a sustainable level, essentially removing the genetic strains that were imprinted with the information necessary to spawn in the great lake tribs. (correct me if i am wrong but my understanding is that reintroducing self sustaining populations of atlantic salmon is not as easy as taking atlantics from new brunswick or elsewhere and placing them in other bodies of water).
anyone have any thoughts or info on the matter?

01-03-2006, 11:00 PM

When I lived in Montana (1979-1991), I saw a wonderful trout river, the lower Flathead have the trout populations just decimated by northern pike, which were illegally planted in some irrigation ponds. Upon the ponds being flushed to replace aging headgates, the pike went for a swim right to the Flathead. Granted there are some huge pike in the Flathead, many are 40lb fish and it is fun catching them; but the westslope cuttroat, bull trout, rainbow trout were just decimated and IMO, the pike fishing as good as it is, does not replace the fine trout fishing this large river once had. Also, the lower Clark Fork River below the mouth of the Flathead (which is a very large river of 200-300 yds wide) had also been adversely effected by the pike as the have migrated downstream.

The once famous bull trout fishery of the upper Flathead and its 3 forks has all but been killed by the introduction by Montana F&W of mysis shrimp. The shrimp have all but taken over eating the plankton that the Kokonee Salmon (landlocked sockeye) which were native to Flathead Lake causing the salmon population to crash. There went the major food source for the bull trout once the bulls got to be 5lbs or so in size. Now the Flathead bull trout are endangered and the wonderful fishery where one could go out and reasonably expect to catch 2 or 3 bull trout of 10lbs to 25lbs in a day are now gone.

01-04-2006, 05:43 AM
Let's not forget that the phenomenal water clarity in lake Ontario is to zebra mussels, an invasive species. I understand the lake is clearer now than it's been in the last 100 years.

01-04-2006, 08:08 AM

When last I talked to the Biologist that was in charge of the Atlantic program in lake Ontario, they were having problems getting them to return. They would dump em into the tributaries and most of them would promptly disappear off the face of the planet or so it would seem. Every once in while you will hear of someone catching one but they are few and far between. Iím sure you are correct about the thiamine deficiency having part to do with it but I would be willing to bet there are many more factors involved. Even ocean mortality, remember, fish in lake Ontario can make it out to sea if they please and it is believed that lake Ontario Atlantics historically did migrate out to the ocean. At this point in time I have not heard if they are still continuing with the program or not, its been a few years since I talked to that Biologist.


The clarity of water is not necessarily a good thing. Think about what flytyer said about the mysis shrimp on Flathead Lake. There is a good lesson for us to learn in his story. They cleaned up all the plankton that the Kokonee fed on and caused their decline. The same thing is happening on the Great Lakes because of the zebra mussels. They are removing the plankton that smaller fish feed on thus causing a decline in the forage base. From what I have been told it hits some fish harder than others. The Salmon population on Lake Ontario has been greatly affected by the decline. The world record Coho came out of Lake Ontario, now you are lucky to even see Cohoís in an Ontario tributary. And the Chinooks have been declining in size every year. The Musky population has also suffered greatly. About the only species that have benefited are the Sheephead (freshwater Drum) and the Smallmouth Bass. Sheephead can feed directly on zebra mussels (they have shell crushers in there throats like bone fish) and crayfish also feed on them. And as everyone knows Bass love crayfish.

It will be interesting to see what comes in the future. Some of the other Biologists I have talked to say that the changes that are occurring are far from over. The great lakes are still evolving because of the new species and its not going to stop for a long time. :confused:


01-04-2006, 08:17 AM
Does anyone know what the original forage base was for that insane atlantic run that used to be in Lake Ontario (before alewives were introduced)?

The Salmon River was so named because of it's run of tens of thousands of magnificent native atlantics that choked it each year.

01-04-2006, 08:56 AM

Rainbow Smelt. They are still common but not what they used to be. Not by a long shot.


01-04-2006, 11:40 AM
thanks for the info on the atlantics
its rather quite a shame that these magnificent fish are so scarce in what was once their native habitat.

01-05-2006, 08:07 AM
Here is a link to an article that gives a pretty comprehensive picture of what the lakes biomass was like prior to european settlement. Also talks in depth about the many factors that led to the decline of Salar. The first half of the article is well worth the read.

tight lines

01-05-2006, 08:34 AM
Charlie, my opinion on what is probably the greatest threat to our fisheries is habitat loss. In reality, much of the Great Lakes sport fishery is not naturally self sustaining. Correct me if I am wrong, but I think that none of the PA steelhead fry production is natural not to mention the fact that it is a non-native species anyway. Urbanization and agriculture are huge problems. Warming of streams owing to clearing of headwater forests, damming to make reservoirs with top water draw, fertilizer and pesticide runoff and canalization of streams to prevent flooding. Perhaps one of the greatest future threats in the Great Lakes is water diversion. I would not rank species invasions as important as any of these simply because peoples sensibilties have changed and will change again and the Great Lakes have been so disturbed for so long that the definition of a desireable fish community has also changed over time. It probably wont be long before sport fishing lobbies think it will be great to introduce genetically modified frankenfish that will grow to 10 lb in a year or two and there will be numerous economic arguments to support them.

01-05-2006, 09:53 AM
I hope everybody reads the link Dmas has provided - we should all know what to prevent going forward.

01-05-2006, 01:35 PM
I agree, the link Dmas provided is very interesting and greatly supports what Rimouskois stated. That is really the bottom line. Very few rivers and creeks in the great lakes support wild fish. We should strive to protect any of them that do.


01-07-2006, 01:49 PM
That's an interesting article, but I'm a little perturbed to find te author linked to 'Environment Probe', wich appears to be an extremist 'green' organization that seems to make it's money by crying 'wolf' on a variety of causes and then collecting donations from tose who respond.
Would anybody know what his research credentials are?

PEte A
01-15-2006, 10:06 AM
Couple of notes to add:

1. Smelt are not native in Lake Ontario or any of the other Great Lakes, so they would have not been the forage of Atlantic salmon populations. Forage might have included the abundant native cisco as well a few species of sculpin.

2. It is thought that there were both ocean going and lake maturing type atlantics in Lake Ontario.

3. Ontario has many many tributaries (hundreds) that produce wild salmonids, as do the US states of the upper Great Lakes.

PEte Addison

01-15-2006, 05:24 PM
Dmas -- Thanks for the interesting report. I was roughly aware of the story of the demise of the atlantics in Lake ontario, but this report added a lot of detail I wasn't aware of. Its a shame how we've let this magnificent fish decline so badly. I'm in touch with a fly tyer from Scotland. They still seem to have a number of excellent salmon rivers over there. And I get the impression they are rather cavalier when it comes to C&R. Yet they have salmon fishing whereas atlantics, in the US at least, are largely gone.

01-21-2006, 05:08 PM
when you look at what we have done to the environment in the US. Dams on the rivers, riparian habitat desctruction, commercial fishing, etc. then we wonder what happend to the fish you could take by the wangonload with a pitchfork at one time.

There are several good books that cronicle what happened and what we must do, if we truly want the fish back.

Earle Fletcher
01-26-2006, 10:32 AM
You don't normally think of Atlantic Salmon as invasive species, but if they have escaped from farming pens they are; and are considered a threat to the wild salmon stocks on both the east and west coasts. I have attached (I hope. This is my first try at adding a picture) a copy of a warning card issued by the Alaska Department of Fish and Game about the invasive Atlantic Salmon.

02-04-2006, 10:03 PM
one man's pest is another man's passion... It all depends upon the context and where they're from...