Thesis
Comparative biology of the west coast and south coast populations of the Breaksea Cod Epinephelides armatus in Western Australia
Honours, Murdoch University
2022
Abstract
The Breaksea Cod Epinephelides armatus (Serranidae) is endemic to ~ 1,600 km of Western Australian coast, ranging from Shark Bay on the west coast (~26°S) to Esperance on the south coast (~122 E) and is an important recreational fishery resource. The aims of this study were to 1) determine the length and age distributions for E. armatus on the west and south coast; 2) estimate the parameters for growth, reproduction (spawning periods and sexual maturity) and natural mortality (M) of west and south coast populations; 3) compare these parameters between a) the west and south coast, and b) for west coast fish, compare estimates of those biological characteristics from this study with those from ~10 years previously; and 4) determine whether the patterns of growth and reproduction on the west and south coast follow the predictions of the three ecological theories (Metabolic theory of ecology, Temperature size rule, Gill oxygen limitation theory).
Samples of E. armatus total length >300 mm were obtained mainly from fish frames submitted by recreational fishers to the Department of Primary Industries and Regional Development, while smaller fish were collected during this study by spear fishing on both the west and south coasts. The results of this study demonstrated von Bertalannfy growth curves differed significantly between the west and south coasts, with fish on the south coast reaching a larger size than those on the west coast but had a lower instantaneous growth rate (k). The mean length at age of west coast males were always greater than those reported by previous studies. Epinephelides armatus had a protracted spawning period (November to April), with a peak in February which would influence the wide ranges of length at age. The length at maturity estimates for females did not differ significantly between the west (285 mm) and south coast (280 mm) populations and these estimates were smaller than the minimum legal length of 300 mm.
Details
- Title
- Comparative biology of the west coast and south coast populations of the Breaksea Cod Epinephelides armatus in Western Australia
- Authors/Creators
- Jacob K Buckland
- Contributors
- Neil Loneragan (Supervisor) - Murdoch University, Centre for Sustainable Aquatic EcosystemsPeter Coulson (Supervisor)D.V. Fairclough (Supervisor) - Murdoch University
- Awarding Institution
- Murdoch University; Honours
- Identifiers
- 991005588669207891
- Murdoch Affiliation
- School of Environmental and Conservation Sciences
- Resource Type
- Thesis
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