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Title:

Maximise yield or minimise risk in the Blacklip Abalone fishery: using biological data to direct harvest strategies

Project Number:

2015-017

Organisation:

SARDI Food Safety and Innovation

Principal Investigator:

Ben Stobart

Project Status:

Completed

FRDC Expenditure:

$272,978.00

Program(s):

Environment, Industry

Need

Increasing fishing efficiency is one of the main ways fisheries can improve their profitability. This can be achieved in two ways for species that exhibit seasonal variation in weight – harvesting fewer individuals for the same catch (raise CPUE by increasing stock abundance), or catching the same number of fish but obtaining a larger catch (increase catch per day and overall). Recent research has demonstrated there are benefits to changing the fishing season in greenlip abalone, using information on their seasonally variable biology, to increase revenue, reduce exploitation rates, or achieve a combination of these two management objectives. This research has resulted in changes to seasonal greenlip fishing patterns made by Industry in the Western Zone of South Australia. Blacklip abalone constitute 82% of the Australian abalone catch, so considerable benefits could be obtained from changes to the fishing season if they exhibit similar seasonal biological traits to greenlip. However, there are currently insufficient data to evaluate this. This project will address the need for additional information on the seasonal biology of blacklip and, following the success with greenlip, has been developed in direct response to the Western Zone of the South Australian abalone fishery seeking similar information on blacklip abalone. The proposal was discussed and supported by members of the Abalone Council of Australia in Adelaide on the 2nd May 2014 and is also a high priority for PIRSA Fisheries and Aquaculture. The project will enable an analysis of newly obtained and existing data using the model already developed for greenlip. The outputs will be a cost-benefit analysis across a range of temporal fishing pattern scenarios. The key outcome will be adjustment of seasonal blacklip harvests, by industry, to maximise profitability.

Objectives

1. Quantify the seasonal and spatial variation in the blacklip abalone shell size/whole weight/meat weight ratios

2. Incorporate the biological data into the existing greenlip model and apply under the monthly fishing scenarios developed in consultation with Industry

3. Provide model outputs from each fishing scenario that detail the number of abalone harvested and their value. This information will allow Industry and managers to maximise the efficiency of their blacklip fisheries.

Maximise yield or minimise risk in the Blacklip Abalone fishery: using biological data to direct harvest strategies

Final Report
ISBN:978-876007-11-9
ISSN:
Author(s):Ben Stobart
Date Published:January 2019
The primary goal of this research was to identify attributes of the seasonal biology of Blacklip Abalone (Haliotis rubra; hereafter referred to as Blacklip) that may be beneficial for optimising fishing strategies. The optimum months to harvest Blacklip to maximise yield were identified using a model adapted from previous work carried out on Greenlip Ablaone (Haliotis laevigata; hereafter referred to as Greenlip). By adapting fishing strategies to harvest Blacklip during the optimum months, fishers can either (1) harvest fewer Blacklip for the same total allowable commercial catch (TACC) taken, or (2) adopt a co-management strategy where they harvest the current number of abalone that are heavier and thus allowing a higher TACC. 
The project results provide the opportunity to change the seasonal timing of harvest to reduce exploitation rate, increase landed revenue, or achieve a combination of these two management objectives. These outcomes are consistent with the priorities of industry - to reduce risk to Australia Abalone fisheries, optimise harvests and improve fishing efficiency.