As we swing into the serious fair-weather fishing season, here is a n interesting blurb on the impacts of C&R and "Keeping them Wet"...excerpted from KEEP 'EM WET:
FINSIGHTS - TRANSLATING THE SCIENCE OF FISHERIES REPORTS #7
May 13, 2017
by Bryan Huskey
Finsights #7 – “I saw the fish swim away so it must be fine” - Part 3
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| Robert Lennox Photo |
My
last two posts have been about the range of possible lethal and
sublethal impacts of catch and release angling on fish, and I want to
round out the discussion with one last post. When it comes to sublethal
effects, it’s fairly easy to comprehend the direct consequences of
angling on an individual fish. What can be more difficult to understand
.....
and discern scientifically is how angling could impact an entire population of fish.
and discern scientifically is how angling could impact an entire population of fish.
One way to
get at population level effects is to examine how angling impacts the
fitness of fish. Keepemwet Science Ambassador John McMillan recently provided a nice explanation
of what fitness means for fish - the ability of an individual to
contribute viable offspring to the next generation. So, a decrease in
fitness would be a decrease in the number or the quality of offspring
from a given fish.
The research paper for this blog post specifically looked at whether catch and release angling impairs fitness.
What did they find?
• 20% of the salmon in the river were angled and were the parents of 22% of the offspring. This means that the fish that were caught and released were able to spawn.
• Larger angled salmon produced significantly fewer offspring than non-angled salmon, however, there was no difference in number of offspring (in angled vs. non-angled fish) for smaller salmon.
• Air exposure decreased the fitness of salmon. Depending on water temperature, the reproductive success was 2 to 3 times lower for angled salmon that were air exposed versus those that were not.
• 20% of the salmon in the river were angled and were the parents of 22% of the offspring. This means that the fish that were caught and released were able to spawn.
• Larger angled salmon produced significantly fewer offspring than non-angled salmon, however, there was no difference in number of offspring (in angled vs. non-angled fish) for smaller salmon.
• Air exposure decreased the fitness of salmon. Depending on water temperature, the reproductive success was 2 to 3 times lower for angled salmon that were air exposed versus those that were not.
