Research Document 2024/067

Identifying a Limit Reference Point for Striped Shrimp (Pandalus montagui) in Shrimp Fishing Area 4

By Baker, K.D., Anderson, S.C., Coffey, W., Walkusz, W., Mullowney, D.R.J., and Skanes, K.R.

Abstract

Off Atlantic Canada, Striped Shrimp (Pandalus montagui) are fished in Eastern Assessment Zone (EAZ), Western Assessment Zone (WAZ), and Shrimp Fishing Area (SFA) 4. Although there is assumed to be strong mixing and movement of the population throughout these areas, each of the three zones are assessed independently. To counteract this spatial-scale mismatch, and in accordance with Fisheries and Oceans Canada (DFO) Precautionary Approach (PA) framework, a limit reference point (LRP) for Striped Shrimp based on the combined survey data time series (2005–22) of SFA 4, EAZ, and WAZ was developed from a spatiotemporal model that created a new fishable biomass index for the entire region (FB_pop) to determine the stock status in SFA 4. The LRP was based on FB_pop and was calculated as the average of three methods:

1. the lowest fishable biomass at which the stock increased and remained above the geometric mean for a period of at least three years,
2. 40% of the geometric mean of the fishable biomass index throughout the time series, and
3. the lowest observed fishable biomass in the time series.

An LRP based on methodology, rather than an estimate of biomass, and a consistent reference period (2005–22) will allow for adjustments as model refinements are made and additional data are collected. In recognizing FB_pop as an index, the status of SFA 4 Striped Shrimp will be provided based on its relatively position in relation to the LRP. In addition to an LRP, three additional indicators of stock health were identified as important metrics for monitoring and reporting to highlight any concerning trends (“red flags”): potential predator index (ecological outlook), total egg production index (reproductive health), and SFA 4-specific fishable biomass index (local population health). In 2022, FB_pop was estimated to be five times the LRP with high certainty. Other indices of stock health (the potential predator index, total egg production index, and SFA 4-specific fishable biomass index) showed no cause for concern.

Research Document 2024/067 (PDF, 9,420 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.