Post by larryhalyk on Jan 28, 2015 10:42:55 GMT -5
Nick, Ryan and John have given you some great answers Doug, but I might as well beat this horse into the ground because that is what I do best.
Summer run strains in the west coast are a response to selection pressures on rivers with nursery habitat located a long distance (usually 100 miles plus) from the ocean or by waterfalls/canyons that can only be passed during certain temperatures and flow conditions. Remember that steelhead are cold blooded and their swimming/jumping ability is optimum between 50 and 60 degrees F. In addition to selection for run timing, these barriers (if they are imposing) can also exert selection pressures to produce big, strong fish. The Thompson River in BC supports a summer run strain that has a reputation for being some of the biggest and strongest steelhead on the planet. Returning Thompson River adults have to wait until the flows drop and water warms in late August to get through the Hell's Gate canyon on the Fraser River, and even though they don’t arrive on the Thompson in peak numbers until late October or early November, they are still considered summer run fish.
Here on the Great Lakes, many rivers supporting wild steelhead have had 100 years of selection pressure to develop their own river-specific strains. On most of these rivers, the bulk of the run waits until late winter or early spring to enter the river but on many, a good portion of the run will enter the river in mid-late fall and either overwinter in the river to spawn in the spring (if deep pools, strong groundwater discharge or other factors that provide good overwintering conditions exist) or they will actually back down to the lake and start all over in the spring.
The primary hatchery steelhead stocked in New York State is the Chambers Creek strain, which has a strong tendency to run in the late fall and through the winter (November to March) because the hatchery personal who developed this strain selected the earliest returning winter run adults in Washington State where they are developed. This is one of the reasons why the bulk of the Salmon River NY steelhead run starts to arrive in mid-November even though water temperatures are suitable much earlier in the fall. These are technically winter run fish even though some may run in October or even September.
Some of your WNY rivers also have a wild fish component, and depending on the availability of overwintering conditions, it may be advantageous from an evolutionary point of view for a good portion of them to run earlier in the fall once the rivers cool down enough to support them. I would be curious to learn from you guys if you think that many of the mid –September or early October steelhead you catch look wild (long straight dorsal fins) vs. hatchery reared (shorter deformed dorsals).
Here in Ontario, the vast majority of Great Lakes tributaries support steelhead runs that are 100% wild. Many of our streams also have excellent overwintering conditions for returning adults (deep pools, lots of groundwater to moderate temperatures and reduce frazzle ice) so many of our fish run in the fall once the water cools down enough to make it comfortable for them to enter them. Our biggest Lake Erie tributary also has a unique selection pressure that forces the majority of its fish to run even earlier in the fall (mid-September to late October). This river has an 8 foot high dam 50 km upstream of the rivermouth. Any fish that doesn’t get over this dam by the time the river temperature gets below their optimal swimming/jumping ability in mid-November is not going to pass on its genes to the next generation because once the “metabolic window” for fish passage opens up again in mid-April, it’s too late for them (especially the big “egg wagon” females) to get over the dam and swim another 50+ km upstream to spawning grounds that are located 100 – 150 km from the lake. These fish are also evolving to become big and strong because the fishways on this dam don’t work and the only way for them to get over the dam is to jump on the dam face and churn their way up a 45o angle through a 10 foot curtain of water (survival of the fittest).
It would be interesting to see what would happen on your biggest Lake Erie tributary if the state stopped stocking and increased effort to improve access to suitable spawning and nursery habitat. I understand that they are investigating the possibility of modifying the dam at Springville to allow steelhead passage. Certainly my first concern would be to protect native brook trout populations, but once that issue is addressed (if it can be addressed), it would be kind of cool to make the passage over that barrier imposing enough to force selection pressures for big strong fish that have to run in the early fall. Selecting for quality and not quantity would give you better opportunities for dry line steelhead. The water temperatures in the 55 – 65 degree range make for some very aggressive fish.
Sorry for the rambling and musings. It’s cold out and I’m just a retired biologist sitting around with my third cup of coffee and procrastinating on my report writing tasks for my Trout Unlimited chapter. Guess it’s time to wander over to the fly tying table.….
Summer run strains in the west coast are a response to selection pressures on rivers with nursery habitat located a long distance (usually 100 miles plus) from the ocean or by waterfalls/canyons that can only be passed during certain temperatures and flow conditions. Remember that steelhead are cold blooded and their swimming/jumping ability is optimum between 50 and 60 degrees F. In addition to selection for run timing, these barriers (if they are imposing) can also exert selection pressures to produce big, strong fish. The Thompson River in BC supports a summer run strain that has a reputation for being some of the biggest and strongest steelhead on the planet. Returning Thompson River adults have to wait until the flows drop and water warms in late August to get through the Hell's Gate canyon on the Fraser River, and even though they don’t arrive on the Thompson in peak numbers until late October or early November, they are still considered summer run fish.
Here on the Great Lakes, many rivers supporting wild steelhead have had 100 years of selection pressure to develop their own river-specific strains. On most of these rivers, the bulk of the run waits until late winter or early spring to enter the river but on many, a good portion of the run will enter the river in mid-late fall and either overwinter in the river to spawn in the spring (if deep pools, strong groundwater discharge or other factors that provide good overwintering conditions exist) or they will actually back down to the lake and start all over in the spring.
The primary hatchery steelhead stocked in New York State is the Chambers Creek strain, which has a strong tendency to run in the late fall and through the winter (November to March) because the hatchery personal who developed this strain selected the earliest returning winter run adults in Washington State where they are developed. This is one of the reasons why the bulk of the Salmon River NY steelhead run starts to arrive in mid-November even though water temperatures are suitable much earlier in the fall. These are technically winter run fish even though some may run in October or even September.
Some of your WNY rivers also have a wild fish component, and depending on the availability of overwintering conditions, it may be advantageous from an evolutionary point of view for a good portion of them to run earlier in the fall once the rivers cool down enough to support them. I would be curious to learn from you guys if you think that many of the mid –September or early October steelhead you catch look wild (long straight dorsal fins) vs. hatchery reared (shorter deformed dorsals).
Here in Ontario, the vast majority of Great Lakes tributaries support steelhead runs that are 100% wild. Many of our streams also have excellent overwintering conditions for returning adults (deep pools, lots of groundwater to moderate temperatures and reduce frazzle ice) so many of our fish run in the fall once the water cools down enough to make it comfortable for them to enter them. Our biggest Lake Erie tributary also has a unique selection pressure that forces the majority of its fish to run even earlier in the fall (mid-September to late October). This river has an 8 foot high dam 50 km upstream of the rivermouth. Any fish that doesn’t get over this dam by the time the river temperature gets below their optimal swimming/jumping ability in mid-November is not going to pass on its genes to the next generation because once the “metabolic window” for fish passage opens up again in mid-April, it’s too late for them (especially the big “egg wagon” females) to get over the dam and swim another 50+ km upstream to spawning grounds that are located 100 – 150 km from the lake. These fish are also evolving to become big and strong because the fishways on this dam don’t work and the only way for them to get over the dam is to jump on the dam face and churn their way up a 45o angle through a 10 foot curtain of water (survival of the fittest).
It would be interesting to see what would happen on your biggest Lake Erie tributary if the state stopped stocking and increased effort to improve access to suitable spawning and nursery habitat. I understand that they are investigating the possibility of modifying the dam at Springville to allow steelhead passage. Certainly my first concern would be to protect native brook trout populations, but once that issue is addressed (if it can be addressed), it would be kind of cool to make the passage over that barrier imposing enough to force selection pressures for big strong fish that have to run in the early fall. Selecting for quality and not quantity would give you better opportunities for dry line steelhead. The water temperatures in the 55 – 65 degree range make for some very aggressive fish.
Sorry for the rambling and musings. It’s cold out and I’m just a retired biologist sitting around with my third cup of coffee and procrastinating on my report writing tasks for my Trout Unlimited chapter. Guess it’s time to wander over to the fly tying table.….
