Identifying factors affecting the low western rock lobster puerulus settlement in recent years

Funded Activity Summary

The puerulus settlement in 2007/08 was the second lowest in 40 years and follows a number of years of below-average puerulus settlements. The settlement for the August and September 2008 indicate that the 2008/09 settlement may be even lower. Previous studies have shown that environment factors such as the Leeuwin Current and storms in late winter/spring affect the abundance and spatial distribution of puerulus settlement. However with the series of low recruitments currently being experienced, it is important to identify if (a) there are other environmental factors, which may be contributing to the low recruitment, (b) if the breeding stock in certain parts of the fishery are particularly critical, and (c) if there are any long-term trends apparent in these environmental factors. Advances in quality of satellite data in the 1990s measuring sea surface topography (altimeter satellites) and chlorophyll/productivity (ocean colour satellite) have enabled significant improvements in our understanding of the environmental factors, with the assistance of oceanographic modelling. Previous oceanographic models were focussed on the open ocean circulation off the continental shelf. Recent advances in modelling enable the development of high-resolution models at 10 km spatial scale which resolve the dominant processes on the shelf. Future climate projection using the same modelling framework have been proposed in WAMSI research. Understanding the causes of recruitment variability and their long-term trends has important implications in the stock assessment and management of the fishery. The management response would be significantly different if the cause of the series of low recruitment was due to egg production (overall or particular parts of the fishery) or environmental factors. Similarly an adjustment to the sustainable harvest rate may be required if there are long-term environmental trends that affect the average recruitment of the western rock lobster.

Objectives:
1. To use a larval advection model and the rock lobster population dynamics model to assess the effect of the spatial distribution of the breeding stock on the puerulus settlement
2. To assess environmental factors (water temperature, current, wind, productivity, eddies) and breeding stock affecting puerulus settlement
3. To examine climate change trends of key environmental parameters and their effect on the western rock lobster fishery

Funded Activity Details

Start Date: 01-07-2009

End Date: 30-06-2012

Funding Scheme: Funding Scheme not available

Funding Amount: $408,405.00

Funder: Fisheries Research and Development Corporation

Research Topics

ANZSRC Field of Research (FoR)

There are no FoR codes available for this funding activity

ANZSRC Socio-Economic Objective (SEO)

There are no SEO codes available for this funding activity

Other Keywords

Aquaculture | Biology | Climate Change | Commercial Species | Data | Ecosystem | Fisheries Management | Life History | Modelling | Oceanography | Population Dynamics | Productivity | Remote Sensing | Reproduction | Stock Assessment

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