The Salish Sea Marine Survival Project continues to examine salmon mortality numbers in the waters near Nanaimo.
The project launched in 2013 and Vancouver-based Pacific Salmon Foundation is a proponent. The goals are to rebuild the production of wild Pacific salmon in areas of the Strait of Georgia, including near Nanaimo, said Brian Riddell, foundation CEO, at the B.C. Salmon Farmers Association seminar on marine environmental collaboration at the Vancouver Island Conference Centre last week.
Riddell said there were 33 projects started in the Strait of Georgia in 2015. One project was the installation of 1.2-centimetre Passive Integrated Transponder electronic tags into small salmon, with a detection area set up in the Cowichan River.
The tags don’t require a battery and will help researchers test a hypothesis that states there is a high mortality rate for juvenile salmon the first few months they are at sea – it decreases the older a salmon gets.
Riddell said researchers believe the vast majority of fish could be lost in the first two or three months in the Strait of Georgia, although the exact time and location is not known. By injecting fish with the tags, researchers can essentially create tagged populations for that time period in different areas.
“We don’t need to do it at 25 days, or 50 days using an individual-based model, we can just look at the probability of survival of fish that is tagged in the area that gets back to the terminal spot,” said Riddell.
In terms of research near Nanaimo, Riddell said there is monitoring taking place in the vicinity of Five Fingers Island. Researchers can’t study ecosystems in a fragmented manner, at different times and places. A broad scale study is needed, he said.
“The only thing that’s sort of site specific is we are seeing evidence that really understanding chinook salmon has to be very localized in knowledge, whereas coho and steelhead, that are bigger fish ... there’s much more generalized trends across bigger areas.
“So we’re starting to pick up a few of these signals. So if someone really wanted to focus on Nanaimo River chinook, then we’d really have to come in and look at the estuaries specifically and that sort of thing,” said Riddell.