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Stock assessment - Pacific salmon

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Overview

Stock assessment information is essential for managing fisheries in a sustainable manner. The following types of information are crucial to the stock assessment process:

  1. In-season stock assessment and re-forecasting of run sizes using information gained from test fisheries, catch monitoring programs and escapement surveys. In-season data provides information on run timing, stock composition, stock abundance, age structure and other information used to make in-season adjustments to management plans.
  2. Post-season evaluations (estimates of total run size, harvest rates, catches, fishing effort, escapement and other factors used to assess whether escapement goals and other management objectives have been met).

Science advisory reports and research documents

The Canadian Science Advisory Secretariat (CSAS) is the national body responsible for review and evaluation of scientific information on the status of living aquatic resources, their ecosystems and the biological aspects of stock management.

In BC, the Centre for Science Advice, Pacific (CSAP) is a regional branch of CSAS, providing scientific advice for the development of management plans for Pacific Salmon, and operates via an open and transparent peer review process. CSAP peer review meetings are comprised of Fisheries and Oceans scientists, Departmental fisheries managers, academics, First Nations, stakeholders, industry, and other government or private institutions.

Science Advisory Reports (SARs) provide advice to DFO management and focus on the long term trends in the status of populations, the current status, and the extent of conservation measures required to maintain the stock's viability for the future. SARs are plain language summaries of in-depth technical working papers on the status of various salmon stocks.

CSAP peer review meetings review science-based assessments in support of fisheries management. Conclusions and recommendations accepted by the group are publicly available in the form of detailed Research Documents, SARs, Science Responses and Proceedings Documents. Advice from CSAP meetings are also provided to senior management through regular updates to the Regional Management Committee.

CSAP publications are available on the national Canadian Science Advisory Secretariat (CSAS) site.

In-season activities

In-season Salmon Bulletins

The Stock Assessment Division (STAD) has a selection of in-season project reports/bulletins and updates. These bulletins provide a summary on the assessment activities of the project and/or a general update on salmon related activities in the area. The bulletin series generally follows a pre-season bulletin outlining the project, with several in-season weekly bulletins, followed by a post season summary report. The bulletins are intended to provide a brief synopsis only. More technical or detailed information is available upon request post season.

Stock re-forecasting

As Pacific salmon begin returning to spawn each year, the Department engages in a process of in-season "re-forecasting", adjusting the pre-season run size forecasts based on actual observations of salmon abundance. These re-forecasts are conducted on a regular basis for various stocks using a variety of analytical models and information from several sources including catch rates in test fisheries and commercial fisheries, other harvest information and escapement surveys. Often, the ocean fisheries in which returns are first detected are on mixed stocks, and mechanisms to differentiate stocks must be in place. Techniques used include DNA analysis, scale analysis, coded wire tags (CWT) from hatchery-produced fish and other tagging programs.

Re-forecast information is typically updated on a weekly basis. As returns build, the reliability of this information increases, with greatest reliability achieved at or past the peak of the run. These weekly updates, many of which are available on the Internet, are key to in-season decision making both by managers and harvesters. Summary bulletins of weekly management decisions based on in-season stock assessments are also available.

Catch monitoring

Reliable catch monitoring is taking on increasing profile as a crucial piece of the stock assessment process.

There is a variety of catch monitoring programs in place for First Nations fisheries. Most major First Nations salmon fisheries including the Fraser River fisheries are monitored and sampled and regular reports are produced. Some First Nations fisheries that involve economic opportunity fisheries have mandatory landing programs. Other fisheries are monitored through catch and effort sampling programs and census data. The Department conducts some programs but most fisheries are monitored by First Nations' technical staff.

In the recreational sector, most major salmon tidal and non-tidal sport fisheries are monitored though creel surveys (interviews of sport fishermen at landing sites), vessel counts (via aircraft overflights), or logbook programs, with some of the fishing lodges and charter operators in Pacific Region. Creel surveys generally operate during peak fishing times only.

In the commercial sector, harvesters are now required to fill out logbooks of all catches and participate in various hail-in programs. In some cases, independent observers are a mandatory requirement to verify catch data to managers. Mandatory landing slips (official records of salmon sold), also provide catch information.

Population monitoring

Coast-wide, Fisheries and Oceans Canada and its partners expend considerable effort to determine salmon escapements (the number of salmon that reach the spawning grounds after "escaping" the fisheries). Most escapement enumeration programs fall under the responsibility of the Stock Assessment Division of Fisheries and Oceans Canada. Work is done with a range of partners, including First Nations and local community organizations. Techniques used include counting fences, visual surveys and mark-recapture programs. Annual estimates of the on-the-grounds escapement are compiled for many stocks by Fisheries and Oceans Canada.

Post-season evaluation

At the end of the salmon harvest and spawning season, actual escapement is compared with pre-season targets to evaluate the effectiveness of management measures. Escapement data are used in the development of subsequent years' forecasts and escapement goals and in tracking long-term trends in survival and productivity.

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