The Kitwanga River is a tributary of the Skeena River, located 250 km from the coast and supports significant runs of Pacific salmon. Kitwanga sockeye are genetically unique and a distinct conservation unit as described under Canada’s Wild Salmon Policy. Historically, sockeye returns to the Kitwanga were in the tens of thousands and they supported a number of sustenance and economic fisheries. In more recent times the stock has been depressed and in many years returns are not enough to meet the minimum biological requirements for the stock. In response to this conservation concern the Gitanyow, with help from organizations like the Pacific Salmon Commission and Fisheries and Oceans Canada, have initiated a rebuilding plan to preserve the genetic uniqueness of the stock and to try and rebuild it to more historical levels. Rebuilding efforts have included the creation of spawning platforms in 2006 and 2007 in Gitanyow Lake, the enhancement of the stock through hatchery production in 2006 & 2007 and a reduction in the overall exploitation rate on the stock through the implementation of strict fisheries management guidelines. The results of the rebuilding efforts have been mixed as the stock has responded positively in some year classes but not in others. To date, millions of dollars have been spent to rebuild the stock and many more millions of dollars have been foregone in lost revenues in the Canadian commercial catch, in efforts to get more spawners back to the Kitwanga River and Gitanyow Lake.

Since 1999, the GFA in partnership with DFO and other organizations have been studying Kitwanga sockeye and Gitanyow Lake in an attempt to better understand the stock and the environment where they reside. Annual smolt and adult enumeration operations have been ongoing for over 10 years, while Gitanyow Lake studies were performed between 1999 and 2003. Lake studies were abandoned due to funding constraints and because it was found that freshwater smolt production from the system at that time was very high and the lake limnology was not likely impacting smolt production. However, since that time we have noticed a significant decrease in freshwater smolt production which has renewed the need to look at the lake biology in more detail.

While targeting abundant species, Canadian commercial seine net fisheries for Pacific Salmon inadvertently capture species of concern that are required to be released. The survival of these released salmon is a key component of assessing the impacts of seine fisheries and developing harvest limits. However, there is poor understanding of post-release mortality in general, especially in chum salmon. Additionally, the handling and release practices employed by the commercial purse seine fleet are inconsistent among individual vessels, likely influencing the probability of survival for released fish.

If handling and release practices can be identified that beget good survival, their implementation would reduce mortality of salmon released from the entire fleet. Adoption of consistent and appropriate release practices will additionally appease public concerns, increase efficiency of harvest, potentially allow additional harvest opportunities and reduce impacts on stocks of concern. Moreover, sociological human dimensions research conducted this past year has identified that commercial fishers would be more willing to modify handling practices if the rationale for doing so was supported by scientific results.

In concert with this finding, the results of this study as well as those from previous research with the commercial fleet has been, and will continue to be, presented to staff from the Canadian Fishing Company (Canfisco), relevant environmental groups, and commercial fishers through seiners associations and advisory boards. Using the 2016 Pacific salmon purse seine fishery in Canadian Statistical Area 3 as a model system, we propose to evaluate how variable handling and sorting practices influence survival and condition following release, and how these relationships change throughout the season.