This primarily focusses on coho salmon, mostly because of the phenomena of pre-spawn mortality that occurs in urban creeks. There is a connection between prespawn mortality and traffic congestion that was interesting enough to study.
They took biological samples to learn more about what happened to salmon when they died before spawning. They also compared coho and chum salmon.
In coho exposed to runoff, there were both more immature red blood cells and more white blood cells.
There are definite differences in the makeup of the blood of the salmon that are exposed to runoff.
They also explored the differences between coho and chum salmon.
Coho and chum salmon seem to have different responses to the same runoff, chum did much better.
Additionally, juvenile coho are also sensitive to runoff. Within hours they’ll die from exposure.
While juvenile coho salmon died quickly, it took juvenile chinook salmon days to die with the same exposure.