Science Advisory Report 2023/034
Scallop stocks assessment in Quebec coastal waters in 2022
- From 2020 to 2022, Quebec’s average annual scallop landings totaled 56.4 t of meat, a 26% decrease from 2016-2019. Fishing effort dropped by 25% on the same period. Sixty-seven % of the landings were from the Magdalen Islands, 31% from the North Shore and 2% from the Gaspe Peninsula.
- Annual landings averaged 17.2 t for the period 2020-2022 and consisted primarily of Iceland Scallops. They decreased by 32% compared to 2016-2019, while fishing effort fell by 44%.
- From 2020 to 2022, there was no fishing effort in areas 16A2, 16C, 16D, 16G, 16H, 16I, 18A and 18D and very little in areas 15 and 16B. Little information is available to assess the scallop status in these areas. There are no recommendations for these areas.
- Since 2013, landings have been less than 16 t compared to levels that were generally above 50 t prior to 2007. Since 2008, fishing has been concentrated mainly on bed D south of Grande Île where recruitment was very good in previous years. Average weight of meat landed has been slightly above the historical average for the last two years.
- The latest research surveys show that the density of non-commercial-size scallop (< 70 mm) remains below the reference mean despite an increase in 2022. More specifically, strong cohorts of small scallops were observed on bed "D" in 2022. The density of commercial-size scallops (≥ 70 mm) remains among the lowest values in the historical series and below the reference mean (1990-2019).
- Output from a new surplus production model indicates that the stock biomass has decreased, reaching 99.69 t in 2022, the lowest level ever recorded.
- A limit reference point has been set to 40% of the theoretical biomass maximum sustainable yield (BMSY), or 182.8 t. The stock has been in the critical zone of the precautionary approach since 2008.
- The exploitation rate estimated by the model indicates that fishing effort would be greater than the level the stock has been able to withstand since 1990, with the exception of 2010 and 2014.
- Minimizing fishing effort on bed "D" would favour the survival of strong cohorts of small scallop observed during the survey in 2022.
- Since the stock is in the critical zone, a rebuilding plan is being developed for Area 16E.
- Since 2009, landings have been less than 5 t compared to levels higher than 25 t prior to 2007. Since 2011, fishing has been concentrated primarily on bed "C". The average weight of meat landed in the last few years has been close to the historical average.
- The 2022 research survey showed that the density of commercial- and non-commercial-size scallops were among the lowest and below the series average in their historical series.
- Reduced fishing effort in recent years does not appear to have led to an increase in densities. Based on the low recruitment observed in the research survey, an increase in densities of commercial-size scallops is not expected in the short term. A rebuilding plan is being developed for this area.
- The fishery in this area resumed in 2017, concentrating on the Île Rouge bed. From 1998 to 2002, this bed was unable to sustain an annual exploitation level of about 10 t. The TAC has been adjusted to 8.72 t in 2020 to address this concern. Because the bed is located at the western edge of the known distribution of scallops and is geographically isolated, it is likely to be more vulnerable to overharvesting.
- Commercial catch per unit effort (CPUE) was relatively high in 2020 and 2022, reaching the reference mean in 2020 and exceeding it in 2022. The current fishing effort on this bed should be sustainable by the time of the next assessment.
- Landings reached more than 60 t prior to 2001, and then gradually declined to totals below 2 t per year since 2018. Fishing effort has also declined and is now very low compared to what it was in the 1990s.
- Scallop landings have increased by 38% while fishing effort has decreased by 2% in 2020-2022 compared to 2016-2019.
- Since 2014, the fishery in this region has been concentrated mainly in Area 19A despite a modest resumption of fishing in area 18B1 in 2022.
- From 2020 to 2022, there was no fishing effort in Areas 17A1, 17A2, 18B2 and 18C, and very little effort in Area 18B1. Since little information is available to assess the status of the resource in these areas, there is no recommendation for these areas.
- Landings and fishing effort were very low between 2020 and 2022. Over the last nine years, fishing effort has been concentrated on two beds, leaving a number of beds unharvested.
- In 2017, the CPUE fell to the lowest value in the historical series, but it has been on the rise since then. The average CPUE for the past three years is above the historical average.
- The weight of meat landed is slightly below the historical average.
- There is a high probability that the current fishing effort on these two beds will be sustainable until the next assessment.
- In Area 20A, Sea Scallop landings and CPUEs increased sharply in 2007 and have remained relatively high since then. Fishing effort is distributed evenly across all beds.
- The 2021 and 2022 research surveys indicate that densities of scallop of all size classes (commercial ≥ 100 mm, pre-recruit 85-99 mm, pre-recruit 70-84 mm and < 70 mm) are high and close to the maximum historical values.
- Decision rules for calculating the fishing effort have been in place since 2010. This effort is calculated using CPUEs derived from logbooks and density indices obtained from the research survey. The 2022 CPUE places the stock in the high CPUE zone, and the density indicators are all above the 85th percentiles of the historical series. For 2023, fishing effort is at the maximum level established under the decision rules for Area 20A, i.e., 430 days at sea.
- The short- and medium-term outlook for the stock in Area 20A is very encouraging. High abundances of 85-99 mm scallops were observed across all beds; these scallops will be available to the fishery in 2023. In addition, a strong cohort of 40-65 mm scallops has been observed in the Centre beds and will recruit to the fishery within 3-4 years. Some kind of protection would be beneficial for maximizing their survival.
This Science Advisory Report is from the regional peer review meeting of March 8-9, 2023 on Scallop stocks assessment in Quebec coastal waters (management units 15 to 20). Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.
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