Publication Date

11-2025

Series Number

6

Publisher

Department of Primary Industries and Regional Development WA

City

Perth

ISBN

978-1-921845-61-1 (Print) 978-1-921845-60-4 (Online)

ISSN

3083-5399 (Print) 3083-5380 (Online)

Abstract

Executive Summary

The western rock lobster (WRL) fishery is considered sustainable with catches being slightly below those associated with the maximum economic yield (MEY) proxy (39% harvest rate), which ensures the large lobster biomass and economical catch rates are maintained. The marine environment continues to be the biggest driver in stock dynamics with post larval recruitment (puerulus) and adult behaviour, including catchability, strongly influenced by oceanic conditions. Recent seasons have seen strong Leeuwin Currents and warm ocean conditions. Over the past few seasons, puerulus settlement levels have been below average at numerous locations and it has been almost 10 years since there was a coast wide above average “spike” in puerulus settlement (2016). The spatial distribution of fishing suggests a possible southward concentration of the lobster stock with the northern end of Zone B potentially showing some signs of reduced productivity. This may be a short-term anomaly or part of a longer-term climate driven progression.

For the 2024/25 fishing season multiple lines of evidence indicate that the WRL resource is at an acceptable level of depletion (LOW risk of unacceptable stock depletion).

This assessment is based on empirical data from the commercial and recreational fisheries, fishery independent surveys and stock assessment models. In summary:

  • Catch and effort data do not indicate a high level of lobster depletion in any region of the fishery.
  • Catch rates remain well above historical levels throughout the fishery.
  • The size composition of lobster measured through multiple surveys does not indicate a high level of lobster depletion in any region.
  • Fishery independent recruitment surveys do indicate a recent period of below average recruitment, but this is most likely associated with unfavourable environmental conditions.
  • Fishery independent surveys indicate that breeding biomass is well above historic levels throughout the fishery.
  • A data moderate (Level 4) fishery wide model estimates that the resource is not over-fished and over-fishing is not occurring.
  • The fine spatial and temporal scale (Level 5) integrated model estimates legal biomass and egg production are well above historic levels and harvest rates are below that used as a proxy for MEY (39%).
  • A continuation of the current TACC (6800 t) will maintain high biomass levels throughout the fishery over the following five fishing seasons.

Number of Pages

107

Keywords

western rock lobster, assessment resource update, dpird, wa

Disciplines

Environmental Indicators and Impact Assessment | Fresh Water Studies

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