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Survey estimates of fishable biomass following a mass mortality in an Australian molluscan fishery

journal contribution
posted on 2023-05-18, 01:52 authored by Mayfield, S, McGarvey, R, Gorfine, HK, Peeters, H, Paul BurchPaul Burch, Sharma, S
Mass mortality events are relatively uncommon in commercially fished populations, but when they occur, they reduce production and degrade ecosystems. Observing and documenting mass mortalities is simpler than quantifying the impact on stocks, monitoring or predicting recovery, and re-establishing commercial fishing. Direct survey measures of abundance, distribution and harvestable biomass provide the most tenable approach to informing decisions about future harvests in cases where stock collapses have occurred because conventional methods have been disrupted and are less applicable. Abalone viral ganglioneuritis (AVG) has resulted in high levels of mortality across all length classes of blacklip abalone, Haliotis rubra Leach, off western Victoria, Australia, since May 2006. Commercial catches in this previously valuable fishery were reduced substantially. This paper describes the integration of research surveys with commercial fishermen's knowledge to estimate the biomass of abalone on AVG-impacted reefs. Experienced commercial abalone divers provided credible information on the precise locations of historical fishing grounds within which fishery-independent surveys were undertaken. Abalone density estimates remained low relative to pre-AVG levels, and total biomass estimates were similar to historical annual catch levels, indicating that the abalone populations have yet to adequately recover. Survey biomass estimates were incorporated into harvest decision tables and used with prior accumulated knowledge of the populations to determine a conservative harvest strategy for the fishery.

History

Publication title

Journal of Fish Diseases

Volume

34

Issue

4

Pagination

287-302

ISSN

0140-7775

Department/School

Institute for Marine and Antarctic Studies

Publisher

Blackwell Publishing Ltd

Place of publication

9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

Rights statement

Copyright 2011 Blackwell Publishing Ltd

Repository Status

  • Restricted

Socio-economic Objectives

Wild caught edible molluscs

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    University Of Tasmania

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