Thank you, Chair. Good evening.
Thanks very much for the invitation to speak to you this evening, albeit briefly.
My name is Brendan Connors. I'm a PhD candidate at Simon Fraser University in the department of biological sciences. I've been there for the past almost five years and I've conducted a bunch of research on various aspects of interactions between farmed salmon and wild salmon. My work combines intensive field observations and controlled experiments with the synthesis of existing data sets on salmon and sea lice populations. I work with scientists from other academic institutions, non-governmental organizations, and the Department of Fisheries and Oceans to ask questions about interactions between farmed and wild fish. I've published seven peer-reviewed publications to date with these other scientists.
I've also been involved in work in the Broughton Archipelago since the spring of 2003. I believe you've heard a considerable amount of previous testimony with regard to pink salmon and sea lice in the Broughton Archipelago, and you're also probably all very acutely aware of concerns with regard to Fraser River sockeye and farmed salmon interactions, particularly here in the Discovery Islands.
I think the work I've done most directly speaks to some of the things you're interested in hearing about this evening. It involves research that looks at some of the broader ecosystem consequences of sea lice transmission from farmed fish to wild fish. Specifically, what I've worked on for the past number of years is understanding how sea lice influence early marine interactions between pink salmon and the salmonic predators that track them during early marine life, particularly coho salmon smolts.
Unlike pink salmon, coho salmon spend, on average, about one year in fresh water before they enter the marine environment. When they do enter the ocean, particularly in areas like the Broughton Archipelago, where there are odd- and even-year cycles of pink salmon, they feed aggressively on pink salmon for the first couple of months of marine life. This predation can be really intensive; it can account for up to about 70% of early marine mortality in pink salmon. This is during the period of time when, in areas where there isn't intensive salmon aquaculture, there aren't usually very many sea lice. What I've been interested in is what the addition of sea lice means for this natural predator-prey dynamic.
Very briefly, in a nutshell, what we've shown is that infected pink salmon are selectively predated upon by coho. That's not surprising, since an infected pink is easier to capture than an uninfected one, but what is surprising is that this comes at a cost to the coho that are feeding on them. Sea lice are incredibly adept at escaping the demise of the pink salmon that they're on and transferring to the coho as the coho feed on those pink salmon. This actually results in the accumulation and intensification of lice on those coho salmon when they're feeding on infected pink salmon. We've estimated that this increases infection twofold to threefold on those coho salmon in areas where they are reared and then interact with infected pink salmon prey.
Most salmon die one way or another during early marine life. Often that's the real bottleneck. A critical question that arose from this research is what consequences, if any, this accumulation of sea lice on coho has on their population level. On the one hand, you can imagine that increased ability to capture and feed on pink salmon may be a net positive for coho salmon population, because there's an increased access to early marine resources. On the other hand, one might hypothesize that as a result of the accumulation of lice impacts on early marine growth, there may be negative consequences.
In an effort to tease apart these different possibilities and ask that question, we've compiled about 35 years of data from Fisheries and Oceans Canada on the number of adult coho salmon that return to both the Broughton Archipelago and to the populations to the west and to the north. They share a very common coastal marine environment, except for some populations that rear and interact around salmon farms and infected pink salmon prey.
What we're able to do is tease apart or control for the confounding influence of climate and fishing pressure and ask if there are any obvious differences between these groups of coho salmon before and during these recurrent infestations that you've heard about in the mid-2000s in the Broughton Archipelago.
The results of the analysis support the hypothesis that sea lice from infected pink salmon from salmon farms are negatively impacting coho salmon populations. In fact, those populations that we looked at were depressed about sevenfold, concurrent with sea lice infestations adjacent to salmon aquaculture.
It's important to note that during that time this was preceding the coordinated changes that have gone on in the Broughton, so analysis of an updated data set is ongoing.
Two really quick key points I want to make before I wrap up is that this research highlights that it may not just be pink salmon that are impacted by sea lice from aquaculture. That's an important point to keep in mind here. There's a potential for disease to propagate through lice. It also highlights that monitoring and rigorous assessment of the health of wild salmon, both at the individual and population level, is imperative to making informed decisions about the viability and long-term sustainability of aquaculture in areas adjacent to wild fish.
Thank you.