Hostname: page-component-7c8c6479df-995ml Total loading time: 0 Render date: 2024-03-29T05:24:05.803Z Has data issue: false hasContentIssue false

Massive mortalities of the black bream Acanthopagrus butcheri (Sparidae) in two normally-closed estuaries, following extreme increases in salinity

Published online by Cambridge University Press:  15 June 2006

S.D. Hoeksema
Affiliation:
Centre for Fish and Fisheries Research, School of Biological Sciences and Biotechnology, Division of Science and Engineering, Murdoch University, Perth, 6150, Western Australia
B.M. Chuwen
Affiliation:
Centre for Fish and Fisheries Research, School of Biological Sciences and Biotechnology, Division of Science and Engineering, Murdoch University, Perth, 6150, Western Australia
I.C. Potter
Affiliation:
Centre for Fish and Fisheries Research, School of Biological Sciences and Biotechnology, Division of Science and Engineering, Murdoch University, Perth, 6150, Western Australia

Abstract

Salinities in some normally-closed estuaries in the central south coast of Western Australia are now frequently becoming highly elevated. This is due to: (1) high evaporation rates in water volumes that, by summer, are already low as a result of atypically dry winters; and (2) increased salt run-off following vegetation clearing in the catchments. A few black bream (Acanthopagrus butcheri) died in the basin and lower reaches of the main tributary of Culham inlet when salinities reached ∼ 77 and 67, respectively, and an estimated 1.3 million black bream died in the tributary during the next two months when salinities continued to increase. All black bream in the basin and the lower reaches of the tributary of another estuary were apparently killed when salinities reached ∼ 83–85. It is proposed that A. butcheri becomes stressed at salinities of 60 and typically die before they reach ∼ 85. In both estuaries, a rock bar in the tributary prevented black bream from moving to refugia in upstream areas where salinities were lower.

Type
Research Article
Copyright
2006 Marine Biological Association of the United Kingdom

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)