4 results
Adoption
PROJECT NUMBER • 2022-063
PROJECT STATUS:
COMPLETED

WRL Communication, Education and Engagement Program

This report encapsulates the achievements and outcomes of the Western Rock Lobster Council's (WRL) Communication, Education, and Engagement Program (Project 2022-063), which aimed to enhance community understanding, trust, and acceptance of the Western Rock Lobster industry. Through innovative...
ORGANISATION:
Western Rock Lobster Council Inc (WRLC)
TAGS
Wild Catch
Survey
Social Science
Social Science
Community
SPECIES
Western Rock Lobster

Develop a strong current warning system and inform knowledge of the nearshore current regime influencing the Western Rock Lobster fishery

Project number: 2017-147
Project Status:
Completed
Budget expenditure: $182,000.00
Principal Investigator: Chari Pattiaratchi
Organisation: University of Western Australia (UWA)
Project start/end date: 31 Dec 2017 - 29 Dec 2021
Contact:
FRDC
TAGS
Wild Catch
Stock Assessment
Oceanography
Modelling
Fishing Gear
SPECIES
Western Rock Lobster

Need

By combining this greater coverage with information derived from commercial fishers (e.g. days when gear is drowned or lost to determine key current velocities) a purpose built webapp can be developed, hosted on an existing service, which allows fishers to asses the risks posed by ocean currents to their fishing operation before they set their gear. This would also allow for fishers to predict days when drowned gear may resurface and therefore the fishing operation may continue.

In addition to this helping the fishing operation, greater current modelling coverage over this part of the fishery will allow for the fine-scale assessment of the links between water movement and puerulus settlement. As part of FRDC project “2016-260 WRL IPA: assess causes and implications of anomalous low lobster catch rates in the shallow water areas near the centre of the Western Rock Lobster fishery” 40 additional puerulus collectors will be added to the current DOF monitoring program which will provide extensive coverage of settlement rates between Seven Mile, Dongara and Jurien Bay.

Objectives

1. Establish additional coastal radar station
2. Establish a predictive warning system for ocean conditions that can be used by the WRL fishery to improve efficiency
3. Assess the relationship between water circulation and puerulus settlement rates
Environment

Assess causes and implications of anomalous low lobster catch rates in the shallow water areas near the centre of the Western Rock Lobster fishery

Project number: 2016-260
Project Status:
Completed
Budget expenditure: $384,180.50
Principal Investigator: Tim J. Langlois
Organisation: University of Western Australia (UWA)
Project start/end date: 8 Jan 2017 - 19 Dec 2019
Contact:
FRDC
TAGS
Wild Catch
Stock Assessment
Distribution
SPECIES
Western Rock Lobster

Need

A reduction in fishing effort in 2008 and change to quota management in 2010 resulted in record low harvest rates and high biomass levels across the Western Rock lobster fishery.

Counter to this trend however has been the increasingly low catch rates that have been observed in the shallow water areas (20 m) near the centre (and possibly other areas) of the fishery over a much longer time period. The adjacent deep water areas show good catch rates comparable with the rest of the fishery.

The low catch rates in the shallow water (20 m) of the fishery are particularly surprising given the relatively high levels of puerulus recruitment immediately to the north and south of this region, which would suggest there should be high levels of sub-legal and legal biomass, and thus good catch rates in the shallows.

Unlike areas that have recently been impacted by the 2011 marine heat wave (e.g. Kalbarri), the processes behind the atypical catch rates in this central shallow water region are unknown and appear to form a worsening long term trend.

In the short term, this trend could impact stock assessments. In the longer term, an expansion of a low catch rate region could result in significant reduction in the overall productivity of the fishery.

Understanding the processes behind the unexpected low catch rates will allow prediction of future trends, management adaptation and the potential for mitigation.

Objectives

1. Determine the spatial extent and temporal trends in regions exhibiting abnormally low legal catch rates throughout the lobster fishery.
2. Identify the lobster life stage(s) resulting in abnormally low legal catch rates in the main area of low catch rates.
3. Examine factors that may be causative of the abnormally low legal catch rates.
4. Identify the implications of the low-catch regions to the stock assessment and management of the fishery.

Final report

Authors: Tim Langlois Michael Brooker Ashlyn Miller Jessica Kolbusz John Fitzhardinge Simon de Lestang Jason How Oscar Doncel Canon Anita Giraldo Brooke Gibbons Matt Taylor
Final Report • 14.30 MB
2016-260-DLD.pdf

Summary

Current and former West Coast Rock Lobster Managed Fishery (WCRLMF) fishers have anecdotally observed a trend of low catch rates since the 1990’s in the near-shore shallow water areas (<8 m) near the centre of the fishery (Dongara-Leeman). Since the atypically low puerulus counts of 2007-2010, this trend of decreasing catch rates in this area have been reported by fishers to extend out to deeper waters (e.g. to the edge of the shallows, < 20 m). Fishers were concerned that this trend of reduced productivity could be impacting the current stock assessment and has the potential to expand throughout the fishery.

These objectives of the research were achieved, in particular standardised meshed pot catch and release surveys were highly useful to establish the extent of the low catch zone and that sub-legal to early juvenile lobster were found to be indicative of the low catch zone. The iterative assessment process, presented to fishers over multiple workshops, indicated that loss of essential habitat, relating to early juvenile lobster survival or recruitment success, was the most likely causative factor of the low catch zone.
To inform the stock assessment and management of the fishery, the project has highlighted the importance of data on 1) the abundance of sub-legal lobster in near shore habitats and 2) monitoring change in/condition of near shore habitats as a potential indicator of early juvenile lobster survival or recruitment success for the stock assessment and management of the WRL fishery. The project has highlighted that limited historical data is available on these potential indicators, but new FRDC WRL IPA funded projects have subsequently been created to further synthesise available information and collect new data for both early juvenile / pre-recruit lobster abundance (FRDC 2019-159 Independent Shallow Survey) and condition and change in near shore habitats (FRDC 2019-099 Habitat as a limit to Western Rock Lobster recruitment) to further inform the stock assessment and management of the fishery.
This project has demonstrated that the active input of current and former fishers can inform scientific studies and an iterative assessment process, of the potential processes limiting lobster catch rates, presented to fishers over multiple workshops can provide information to further improve the stock assessment and management of the fishery.
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