Research Document - 2015/066

Assessment of the Canadian LFA 41 Offshore Lobster (Homarus americanus) Fishery (NAFO Divisions 4X 5Zc)

By D.S. Pezzack, C. Denton, M. Cassista-Da Ros and M.J. Tremblay

Abstract

The offshore fishery for American Lobster (Homarus americanus) in Lobster Fishing Area (LFA) 41 was assessed based on indicators from the fishery and from fishery-independent trawl surveys. A series of primary indicators were chosen, and boundary levels proposed for each. Secondary indicators that aid in interpretation of trends were also evaluated. The primary indicator boundaries were not considered equivalent to limit reference points and uppers stock references in the sense of Fisheries and Oceans Canada’s (DFO) Precautionary Approach since consideration of multiple indicators is important for this stock. Instead, it is proposed that a combination of abundance and size indicator values be used to define the cautious zone. The primary indicators for abundance are based on the mean number per tow in the DFO Maritimes Region Research Vessel trawl surveys (RV surveys). These indicators have been increasing since the mid-1990s, and are at an all-time high for the 30 year time series. The lowest values are considered to correspond with a healthy and productive state. As a result, there is no “low” point from which to judge potential for recovery. Size is regarded as indicative of the exploitation rate.

Throughout the history of the LFA 41 fishery, lobsters caught have been larger than those in inshore fisheries. A relative fishing mortality rate estimate based on landings and the biomass index from the RV surveys indicates fishing mortality is low and has been declining since the mid-1990s. Primary indicators for size were based on the size of lobsters in the RV surveys and in at-sea samples of the trap catch. The current values of all but one of the eight size-based indicators are above the proposed upper boundaries and, overall, the population size structure continues to be dominated by mature sizes. Based on the current indicators of abundance and fishing pressure, the LFA 41 lobster stock is in the healthy zone and the current total allowable catch (TAC) of 720 metric tonnes (mt), which has been in place since 1985, has had no detectable negative impacts on the lobsters in LFA 41 overall. As such the TAC is considered to represent an acceptable harvest strategy at this time. In the context of the ecosystem, the fishery footprint of the LFA 41 fishery is low compared to the inshore fisheries. This is due to the combination of low fishing effort and large fishing area. The incidental catch of species other than lobsters in traps consists primarily of Jonah Crab, Cusk, Cod, Red and White Hake, and Haddock. The overall incidental catch in 2006 of 154 mt declined to an estimated 46 mt in 2012. Jonah Crab have not been actively fished and retained by the LFA 41 fishery since 2008.

Complete document (PDF, 4130 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.