Terms of Reference

Assessment of Redfish stocks (Sebastes mentella and Sebastes fasciatus) in Units 1+2

Zonal Peer Review – Quebec and Newfoundland and Labrador Regions

March 3, 2016
Mont-Joli (Québec)

Chairperson: Martin Castonguay

Context

Units 1 + 2 Redfish (Sebastes spp.) are distributed in the Gulf of St. Lawrence as well as the Laurentian Channel and Laurentian Fan areas off southern Newfoundland and Northeastern Nova Scotia. Both S. fasciatus and S. mentella in these areas are considered to be in a low relative biomass state and a 2012 peer review meeting showed them to be in the precautionary approach critical zone at 44% and 8% of their biomass limit reference points, respectively. These long lived species have proven difficult to age and age based modelling approaches have not as yet been applied successfully to either of these stocks. Reference point estimates from these stocks are the result of fitting a state-space Bayesian implementation of the Schafer surplus production model, BSP (McAllister & Duplisea 2011, 2012). BSP does not make use of the length composition data available for these stocks and it was agreed at the 2012 reference point meeting that further approaches would be considered that could include these data in hopes of more accurately modelling population dynamics and improving management advice. During a zonal peer review meeting held in December 2015, new modeling approaches have been reviewed to assess the status of Units 1 and 2 redfish populations. Unfortunately, none of the models presented adequately fit the data and further work is required to improve the models. In order to provide advice to fisheries management for the next two years, it was recommended to assess the state of the redfish populations based on indicators.

Objectives

Provide scientific advice on Units 1 and 2 redfish stock status. To the extent possible, evaluate separately the status of Sebastes mentella and of Sebastes fasciatus for Units 1 and 2 combined. This advice shall include:

• Description of the biology of Units 1 and 2 redfish and its distribution;
• A summary of oceanographic conditions;
• Description of the redfish fishery including landings, fishing effort, catch per unit effort, biological data and redfish by-catches in other fisheries;
• An update of abundance and biomass indices derived from DFO and industry surveys (including size structure and geographic distribution of catch);
• Expectations for 2011 and 2012 year class impacting the status of the stock as the cohort recruits to the fishery;
• Review available information on migration of redfish into 3Pn, 4Vn and advice on any appropriate changes to the current fishery closure associated with the mixing period in 3Pn, 4Vn;
• Identification of basic elements to consider for the next assessment;
• Evaluation of the need to follow the stock status during interim years and identification of indicators as appropriate;
• Determination of the next assessment year;
• Identification and prioritization of elements to improve and research projects to be considered for the future;
• Harvest advice for 2016 and 2017 based on available data. Harvest advice should also be communicated taking into consideration the context of two redfish species and two management units (Units 1 and 2).

Expected Publications

• Science Advisory Report
• Proceedings
• Research Document

Participation

• Fisheries and Oceans Canada (DFO) (Science and Ecosystems and Fisheries Management sectors)
• Aboriginal Communities/Organizations
• Provincial Representatives
• Fishing Industry
• Academics and Other External Experts

References

McAllister, M. and Duplisea, D.E. 2011. Production model fitting and projection for Atlantic redfish (Sebastes fasciatus and Sebastes mentella) to assess recovery potential and allowable harm. DFO Can. Sci. Advis. Sec. Res. Doc. 2011/057 vi + 75 p.

McAllister, M. and Duplisea, D.E. 2012. Production model fitting and projection for Acadian redfish (Sebastes fasciatus) in Units 1 and 2. DFO Can. Sci. Advis. Sec. Res. Doc. 2012/103 iii + 34 p.