Terms of Reference

Stock Assessment of Yellowtail Flounder (Limanda ferruginea) in the Southern Gulf of St. Lawrence (NAFO Division 4T)

Regional Advisory Meeting – Gulf Region

February 16-17, 2021
Virtual meeting

Chairperson: Amélie Rondeau

Context

The last complete stock assessment of yellowtail flounder (Limanda ferruginea) in the southern Gulf of St. Lawrence (Northwest Atlantic Fisheries Organization [NAFO] Division 4T) was conducted in 2016 (DFO 2016; Surette and Swain 2016). There has been an annual Total Allowable Catch (TAC) of 300 t for this species since 2002. The yellowtail flounder fishery is conducted mainly in the coastal waters bordering the Magdalen Islands. Large and older flounder are subject to high natural mortality, which has quadrupled over the time series. Fishing mortality is generally low and its contribution to the estimated total mortality of flounder is so small that no difference is seen in stock trends over the next five years under projections of 0 t, 100 t and 300 t per year catches. Across the southern Gulf of St. Lawrence, natural mortality appears to be the most important factor affecting stock status. Abundance indicators were updated in 2019 (DFO 2019). Commercial biomass indices have continued to decline since the last assessment in 2016 to the lowest level ever recorded.

In support of Fisheries and Oceans Canada's (DFO) Ecosystem and Fisheries Management multi-year management approach and the request for advice on a TAC decision for the period May 2021 to May 2026 for the southern Gulf of St. Lawrence yellowtail flounder stock, DFO's Gulf Region Science Branch will conduct a peer review of the status of the yellowtail flounder stock and provide management advice for the fishery targeting this stock.

Objectives

In order to develop scientific advice in support of the multi-year (May 2021-May 2026) TAC decision for yellowtail flounder (NAFO Division 4T), the following elements are taken into consideration:

• The quantity, age and size structure of yellowtail flounder catches from the southern Gulf of St. Lawrence fisheries to 2020.
• Indices of abundance of yellowtail flounder from research vessel surveys and sentinel surveys.
• Best estimates of spawning stock biomass, recruitment, recruitment rates and fishing mortality rates for 2020 from a population model or survey-derived estimates.
• The definition of reference points for the southern Gulf of St. Lawrence yellowtail flounder stock.
• The status of the stock relative to the defined biological reference points.
• Population trajectories based on current productivity rates (growth, recruitment, natural mortality), which assume a maximum annual TAC of 100 t or 300 t of yellowtail flounder, and the probability that the spawning stock biomass is within the Critical, Cautious or Healthy Zone of the Precautionary Approach Framework for 2021-2026.
• Identification of indicators that would be used to characterize stock status in the years between the five-year assessment and management cycle, as well as changes in indicators or characteristics of yellowtail bycatch fisheries that would trigger a new assessment prior to the planned five-year assessment cycle.
• Identification of uncertainties and knowledge gaps.
• Ecosystem considerations, including variations in life cycle parameters, interspecies interactions (e.g. predator, prey), and environmental conditions that influence growth, survival, and recruitment.
• The spatial and temporal distribution of the yellowtail flounder fishery.

Expected Publications

• Science Advisory Report
• Research Document

Expected Participation

• Fisheries and Oceans Canada (DFO) Ecosystems and Oceans Science, and Ecosystems and Fisheries Management sectors
• Industry
• Indigenous organizations
• Provinces
• External experts

References

• DFO. 2016. Stock assessment of Yellowtail flounder (Limanda ferruginea) of the southern Gulf of St. Lawrence (NAFO Div. 4T) to 2015. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2016/033.
• DFO. 2019. Updated indices of abundance to 2018 for American Plaice and Yellowtail Flounder from NAFO Div. 4T. DFO Can. Sci. Advis. Sec. Sci. Resp. 2019/006.
• Surette, T., and Swain, D.P. 2016. The Status of Yellowtail Flounder in NAFO Division 4T to 2015. DFO Can. Sci. Advis. Sec. Res. Doc. 2016/058. x + 74 p.