The spread of mankind and civilisation has reduced many of the local varieties of trout to small numbers and very small areas of refuge. Some efforts are being made to prevent the destruction of these trout species. Here are some podcasts describing what is happening in the US.
Dr. Robert Behnke is one of the foremost authorities on trout and salmon species. In an interview for http://www.itinerantangler.com/ listen to his down-to-earth explanations of the evolution of cutthroat trout, the salvation from extinction of the Greenback and Lahontan cutthroat subspecies, and a little fish called onchonychus clarki behnkeii in this podcast http://www.itinerantangler.com/podcasts/podcast21.mp3 . Dr Behnke is the author of Trout and Salmon of the United States. The Lahontan cutthroat in Pyramid lake one time not so long ago grew to 40lbs but was wiped out by dams and abstraction of it's spawning inflowing river the Truckee River. Thought to be extinct, some Lahontans were eventually found in a far away place, and DNA tested. They were the pure Lahontan strain! So the Lahontan was saved, reintroduced to some places it had disappeared from. But the Pyramid sub-variety of Lahontan cutt is no more. The Lahontans of today don't get over 20lbs. Dr Behnke is fascinating in all this subject.
Podcast about the efforts to save the Ohio strains of Brook trout from http://www.flyfishohio.com/ .
http://www.flyfishohio.com/AudioFiles/Brook_Trout_interview.mp3 . The remaining purebred Ohio brookies they found were confined to under a 1/2 mile of stream you could jump over, and this in a state with 30000 miles of river habitat!
The bit 8 minutes in to the soundtrack sounds incredible. Scientists had identified only two places remaining with these fish living in them. Then a homeowner with land through which one stream flowed, decided to dam it and build a pond. Despite the best efforts to dissuade the landowner, that population were extirpated when the stream was submerged. Not 50 or 100 years ago, this was in 1993!
There is good news. The fishery biologists have located other suitable headwaters of streams, and some of the Ohio brookies are now living in these other tiny places, so there are now 10 populations instead of the one which remained following the fiasco described above. Their odds of survival sound better.
Podcast in http://www.itinerantangler.com/ about Joe Tommeleri the well known angling illustrator.
http://www.itinerantangler.com/podcasts/podcast65.mp3 This interview talks about Joe's angling art, and then goes into interesting ground about his current project. Joe has been finding new species of trout in the isolated mountain streams down in Mexico. What he has to say about American and Mexican trout and the activities of people applies everywhere.
I am an angler in Ireland, and these activities are interesting because we have seen the extinction of Arctic Char in ALL east coast Irish waters in the past 100 years. Our other native species of Pollan are dropping in numbers at an alarming rate.
The new way is to avoid restocking with new trout where numbers are low. This is to prevent the dilution of local trout genetics with stockies from elsewhere. The local trout will have evolved ways and abilities to live successfully in the local rivers and lakes. Compared with stockies, wildies are a far better bet in the odds for survival.
So the current wisdom has changed. It is to fix up the problems with water quality, and reinstate spawning areas which have been damaged by man's activities. Progress is very very slow, and commercial interests (the cost of avoiding pollution by waterside operations) usually work against the trout. Then there are the problems caused by misguided anglers who move alien species into new places, and further stress the fish already in those waters.
The past 25 tears has been very bad for char and pollan in Ireland. Gillaroo and sonaghan in Lough Derg may also be already gone, if recent failures to find them continue.
Salmon have been netted to the point where East coast rivers have had to be closed completely for salmon fishing, adn after several years closed still show little signs of improvement so few are the spawning fish in numbers.
Even the freshwater eel is threatened. Oddball invasive foreign plants are growing on our river banks and in our lakes and these create their own problems which will have to be dealt with sometime.
Our political leaders have allowed this to happen by the simple method of pandering to the interests of those doing the damage. They have avoided their responsibility to legislate against the enemies of our rivers and lakes, and by inaction, caused great harm.
Hopefully the future holds better news than the recent past.
It appears that EU rulings will force their hand and help bring back the clean water we have all been entitled to, but been denied.
The water framework directive is a big step in the right direction. But I fear that old game of seeking 20 year derogations and exceptions to the simple targets of the WFD has already begun by organisations who fear the costs of being made to get their act together.