Another season of smolt counting has wrapped up in Bristol Bay. The counts are part of a broader research project carried out by Bristol Bay Science and Research Institute.
Since 2008, BBSRI has been counting baby salmon as they leave their home rivers, bound for the ocean. The counts are being done to establish some baseline knowledge about the salmon life cycle for fish coming out of the Kvichak, Egegik and Ugashik rivers. Justin Priest is one of the biologists working on the project.
“It’s a monumental task to get the data. So basically, once we can kind of understand the river and the ecosystem for each one of these three river systems, then we can start to say ‘hmm, what caused this peak in this year, or why were the fish slightly bigger in this year and so on.’”
It will be awhile before those kinds of questions can be answered, but Priest says it’s important because the current research that’s used to make management plans is a little less focused. While there has been considerable work done, projected returns are based largely on the number of fish that leave and the number that come back years later.
“So hopefully, eventually, we can get to the point where our data are valuable that we can have them incorporated into the model. Six years between an adult laying an egg and another adult coming back is a long time for a lot to happen," Priest says.
Even though it’s still kind of the early stages, he says what they’re finding so far is, in general, a pretty diverse and healthy population of fish.
“Historically, we don’t know as much about the fresh water life cycle as we would like to. I tend to think of it as counting the number of kindergarteners to estimate the number of adults you’ll have in a few years. Fish and Game managers use this as part of an ecosystem-wide check into making sure that the population is healthy and that the total ecosystem is also healthy.”
In the coming years, the hope is to be able to generate models that can help predict future salmon returns. The way to do that is by identifying all the variables that contribute to both fresh and saltwater growth. That second part is a little more difficult. The ocean is a pretty big place. But there’s a lot that can be done upriver. For instance, what about the winter ice cover on lakes like Illiamna or Ugashik?
"Historically, the ice is really thick on these lakes to where people could walk across the lakes," Priest says. "This is where the fish rear. And the winter has been so warm the past few years that the lakes haven’t been freezing either at all or not completely. So that has to have some sort of effect, you’d think, upon the stock of the smolt. That’s another question we’re trying to answer, is there some sort of climatic-level shift going on in these populations.”
So, for Joe Fisherman out on the water today, why is this important?
“Understanding the sources of variability for each one of these populations I think is really important for anyone that has any interest in Bristol Bay salmon. We need to understand, is the population healthy, is it steady, is it decreasing, are the fish growing? And also understanding that in the context of a long-term data set is quite valuable," Priest says.
"Especially going forward for the future, we have this great understanding of what the smolt schools look like. And maybe if we have climatic-level shifts in North Pacific temperatures, then we could see some sort of effect and have an early warning of the coming run.”
So might we be able to know and not just guess at the strength of a run? Time, and a lot more research just might tell us some day.