Fisheries Research Articles
Impact of mortality, possibly due to herpesvirus, on pilchard Sardinops sagax stocks along the south coast of Western Australia in 1998-99
Document Type
Article
Publication Date
2000
Journal Title
Marine and Freshwater Research
ISSN
ISSN: 1323-1650 eISSN: 1448-6059
Disciplines
Aquaculture and Fisheries
Abstract
During progression of a mass mortality of Australian pilchards in late 1998 and early 1999, quantities of dead pilchards on the sea-surface, sea-floor and along beaches were estimated in three regions along southern Western Australia (WA) by use of transects. Total mortality was estimated at 17 590, 11193 and 144.4 t for Esperance, Bremer Bay and Albany respectively. Mortality rates at Esperance and Bremer Bay were similar at 74.5% and 64.7% respectively, with a mean of 69.6%. In contrast, estimated mortality at Albany was only 2.4%. Although the difference in total mortality between regions is probably related to differences in stock size, as determined by simulation models, the much lower estimate for Albany is probably an artefact of an over-estimated pilchard biomass and not due to large differences in actual mortality rates. Variability in estimates of both pilchard biomass and quantities killed resulted in a wide range of estimated mortality rates, with lower estimates for Esperance and Bremer Bay of 28.0% and 22.9% respectively. This represents a significant decline in the breeding stock of WA pilchards. If the impact was closer to the mean (69.6%), then pilchard stocks in WA are severely depressed.
Recommended Citation
Gaughan D. J. , Mitchell R. W. Blight S. J. (2000) Impact of mortality, possibly due to herpesvirus, on pilchard Sardinops sagax stocks along the south coast of Western Australia in 1998-99. Marine and Freshwater Research 51, 601-612. https://doi.org/10.1071/MF99176
