28 results

Predicting the impacts of shifting recreational fishing effort towards inshore species

Project number: 2010-001
Project Status:
Completed
Budget expenditure: $300,439.06
Principal Investigator: Alex Hesp
Organisation: Murdoch University
Project start/end date: 31 Jul 2010 - 31 May 2013
Contact:
FRDC

Need

Recreational exploitation of inshore, marine fishes near Perth, WA, including King George Whiting, some other whiting species and Silver Trevally, is likely to increase markedly because of effort transfer from offshore to inshore species, due to new fishing regulations to protect offshore demersal species. No reliable stock assessment information is currently available for any of these species, which may already be overexploited. Furthermore, for King George Whiting and Silver Trevally, current assessment methods are inadequate because offshore movements with increasing body size, combined with different catchabilities and fishing pressures in nearshore and offshore habitats, make it impossible to obtain a representative age composition sample for an overall stock of these species. This problem can be addressed through developing a new stock assessment approach for such species, which is also applicable to other recreational, and commercial species, e.g. Estuary Cod.

The biological information published in reports and papers on commercial and recreational fish species in south-western Australia is often inaccessible to fishers and researchers may not be aware of all available information for those species. A book explaining the basics of fisheries science and outlining key information for important temperate WA fish species would be invaluable for engaging fishers and a valuable reference for researchers and managers.

The proposed project directly addresses an urgent need of the Department of Fisheries, WA, and the recreational sector, to assess likely impacts of recreational effort transfer from offshore to important inshore species. The assessment approach and guide is also very relevant to the commercial sector.

Objectives

1. Develop a method for estimating mortality in species which exhibit size-related movements
2. Predict impacts of shifting effort towards certain temperate, inshore WA fish species
3. Produce a guide to key temperate WA fishes, for all industry stakeholders

Final report

ISBN: 978-1-921877-05-6
Authors: Fisher E.A. Hesp S.A. Hall N.G. and Sulin E.H.
Final Report • 2013-09-15 • 1.49 MB
2010-001-DLD.pdf

Summary

The project outputs have led to the following outcomes:

1. A model has been developed enabling reliable estimation of mortality of fish species that undertake size-related, unidirectional, offshore movements from age and length data. This new modelling approach is likely to be applicable to stocks of a number of fish species with this life history attribute, for which current stock status information may be very limited due to the difficulty of obtaining a representative sample for an overall stock.

2. Current age and length composition data and estimates of key stock assessment parameters, including selectivity, movement and fishing mortality, are now available for Silver Trevally and King George Whiting in coastal waters near Perth in Western Australia. Managers are aware that the study results have provided preliminary evidence that Silver Trevally and King George Whiting in waters near Perth are not currently experiencing overfishing.

3. This project has provided managers with information about the relative extents to which the stocks of Silver Trevally and King George Whiting in coastal waters near Perth might be expected to be impacted if fishing pressure were to increase by specified amounts. Managers are thus aware that King George Whiting stocks are likely to be more vulnerable than Silver Trevally to increases in fishing pressure in inshore waters.

4. Detailed summaries of the biology, stock assessment and management for 30 of Western Australia’s most important and/or well-known temperate fish species are now accessible to fishery stakeholders in the form of a species guide (published separately as Fisheries Research Report No. 242 by the Department of Fisheries, Western Australia). The guide provides a comprehensive “go to” source of information for anyone who wishes to find key facts and/or literature relating to these species.

Keywords: Silver Trevally, King George Whiting, size-related movement, fishing mortality, uncertainty, model assumptions

Environment
PROJECT NUMBER • 2003-041
PROJECT STATUS:
COMPLETED

Estimation of natural and fishing mortality using length composition data

The objectives of this project were to develop length-based approaches for estimation of natural, fishing and total mortality, and to explore the application of these methods to the data from selected fisheries. The methods that were developed were essentially length-based versions of age-based...
ORGANISATION:
Murdoch University
Environment
PROJECT NUMBER • 2008-102
PROJECT STATUS:
COMPLETED

Tactical Research Fund: Assessing alternative fishing seasons for red-legged banana prawns in the Joseph Bonaparte Gulf and future directions for collaborative research for NPF Industry Pty Ltd

To enhance its profitability, NPF Industry Pty Ltd needs to develop its capacity to gather key stock status data for each of its stocks so that simple bio-economic models can be developed and used to assess and potentially optimize the value of component NPF stocks. The NPF Industry Pty Ltd needs...
ORGANISATION:
Murdoch University
Environment
PROJECT NUMBER • 1999-154
PROJECT STATUS:
COMPLETED

Determining biological characteristics of the champagne crab (Hypothalassia armata) for management purposes

During recent years, commercial trap fisheries have developed for the champagne and crystal crabs in deep waters off the lower west and south coasts of Western Australia. Thus, data on crucial aspects of the biology of these species were required to enable plans to be developed for conserving their...
ORGANISATION:
Murdoch University
Communities
PROJECT NUMBER • 2016-034
PROJECT STATUS:
COMPLETED

Golden fish: evaluating and optimising the biological, social and economic returns of small-scale fisheries

This project investigates recreational and commercial fisher motivations for using a fishery and the beliefs, attitudes and perceived benefits of aquaculture-based enhancement programs and other management options. It also determines the total economic value for recreational fishing for Blue Swimmer...
ORGANISATION:
Murdoch University
Environment
PROJECT NUMBER • 2005-063
PROJECT STATUS:
COMPLETED

Development of an ecosystem approach to the monitoring and management of Western Australian fisheries

Diversity and ecosystem-based indicators were calculated for commercial finfish fisheries from 1976 to 2005 for the West Coast, South Coast, Gascoyne, Pilbara and Kimberley bioregions. The ecosystem-based indices, which detect changes in the species composition of the food web within the ecosystem,...
ORGANISATION:
Murdoch University
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