Science Response 2017/009

Review of Reference Points used in the Precautionary Approach for Northern Shrimp (Pandalus borealis) in Shrimp Fishing Area 6

Context

Shrimp biomass indices in Shrimp Fishing Area (SFA) 6 have declined to the lowest levels in the twenty-year survey time series. Science advice (DFO 2014 and DFO 2016) has indicated that a decline in shrimp production has been associated with a recent warming trend, early timing of the phytoplankton bloom, increasing biomass of predatory fishes and commercial fishing. The fishable biomass index is expected to remain low, or decline further, in the short-term assuming that unfavourable conditions continue.

The current Precautionary Approach (PA) framework for Northern Shrimp in SFA 6 was developed by a working group which included participation from industry, Fisheries and Oceans Canada (DFO) Fisheries and Ecosystems Management, DFO Science, Government of Newfoundland and Labrador (NL), and Aboriginal groups. It was developed following the PA Workshop on Canadian Shrimp and Prawn Stocks and Fisheries in 2008 (DFO 2009) which included DFO Fisheries and Ecosystems Management, DFO Science, Government of NL, Aboriginal groups, and industry participation. The provisional reference points and harvest control rules developed by this working group have been used in assessments since 2010.

Given the changes in environmental conditions and the predatory fish communities on the NL Shelves, Fisheries and Ecosystems Management requested that Science assess risks associated with potential alternative interim reference points on the basis that a maximum harvest rate of 10% will remain in place if the female spawning stock biomass (SSB) index declines below the current Limit Reference Point (LRP) of 82,000 t (i.e. the harvest control rule currently in place). Consequently, a DFO Science Response Process (SRP) was undertaken on January 25, 2017. No new data since the 2016 Regional Peer Review of the Assessment of Northern and Striped Shrimp (DFO 2016) were available for review.

An assessment model and subsequent revised PA framework will be explored, and peer-reviewed at a framework meeting in 2-3 years.

The objectives of the SRP were:

Provide a summary review of existing information on:

1. Environmental changes, fish community changes, estimations of consumption, and impact of these on net shrimp production.
2. Changes in productivity conditions for shrimp, and whether these changes are expected to continue in the short, medium and long terms. This includes the review of available information from surveys and the fishery before 1995.
3. The role of shrimp as a forage species considering an ecosystem based management approach.

Engage in discussion regarding:

4. The applicability of the reference points in place for Northern Shrimp, given recent changes in the ecosystem and environment, and whether there are alternative interim reference points that could be applied.
5. Qualitative descriptions of risks (including uncertainties and limitations) associated with current and potential interim proxy reference points, recognizing that there is no model for this stock.

This Science Response Report results from the SRP of January 25, 2017 on the Review of Reference Points used in the Precautionary Approach for Northern Shrimp (Pandalus borealis) in Shrimp Fishing Area 6.

Complete document (PDF, 961 KB)

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