11 results
Environment
Environment
PROJECT NUMBER • 2000-137
PROJECT STATUS:
COMPLETED

Determination of the biological parameters required for managing the fisheries of four tuskfish species and western yellowfin bream

Data have been collected on the biology of western yellowfin bream and four tuskfish species that are of the type and quality required by managers for developing appropriate plans for conserving the stocks of these five commercial and recreational species. Emphasis was thus placed on determining (1)...
ORGANISATION:
Murdoch University

Determination of biological parameters required for managing the fishery for West Australian dhufish

Project number: 1996-103
Project Status:
Completed
Budget expenditure: $183,803.00
Principal Investigator: Ian Potter
Organisation: Murdoch University
Project start/end date: 10 Sep 1996 - 13 Sep 2000
Contact:
FRDC

Objectives

1. Determine the age and size composition and growth of Dhufish.
2. Determine the location and period of spawning of Dhufish.
3. Determine the habitats occupied by Dhufish and whether these change with size and maturity.
4. Determine the age and size at which sexual maturity is attained.
5. Determine the fecundity of Dhufish and whether this species spawns more than once in a breeding season.
Environment
PROJECT NUMBER • 2005-063
PROJECT STATUS:
COMPLETED

Development of an ecosystem approach to the monitoring and management of Western Australian fisheries

Diversity and ecosystem-based indicators were calculated for commercial finfish fisheries from 1976 to 2005 for the West Coast, South Coast, Gascoyne, Pilbara and Kimberley bioregions. The ecosystem-based indices, which detect changes in the species composition of the food web within the ecosystem,...
ORGANISATION:
Murdoch University
Environment
PROJECT NUMBER • 1999-154
PROJECT STATUS:
COMPLETED

Determining biological characteristics of the champagne crab (Hypothalassia armata) for management purposes

During recent years, commercial trap fisheries have developed for the champagne and crystal crabs in deep waters off the lower west and south coasts of Western Australia. Thus, data on crucial aspects of the biology of these species were required to enable plans to be developed for conserving their...
ORGANISATION:
Murdoch University

Collection of biological data required for management of the blue swimmer crab fishery in the central and lower west coasts of Australia

Project number: 1997-137
Project Status:
Completed
Budget expenditure: $197,800.43
Principal Investigator: Ian Potter
Organisation: Murdoch University
Project start/end date: 21 Dec 1997 - 13 Aug 2001
Contact:
FRDC

Need

There is a critical need to develop a management policy for the blue swimmer crab fishery in Western Australia, that is based on sound biological data collected for this species in this state. Since the environments in which blue swimmer crabs are caught in Western Australia are unique, it is essential that detailed biological data of this species are collected specifically for these waters. The type of biological data that are required include information on the habitat requirements, size and age composition, growth and reproductive biology of this crustacean species. Reliable data on some of these aspects (size and age composition and reproductive biology) are essentially confined to those obtained for the Peel Harvey Estuary and to those derived from catches obtained in Cockburn Sound, using a trawl net with a large mesh (Potter et al., 1983; Penn, 1977; FRDC project 95/042). From a comparison of data in these latter studies, it would appear that crabs grow to a larger size or live longer in marine waters than in estuaries. There is thus an urgent need to obtain more precise information on the biology of blue swimmer crabs in the different habitats in the marine habitats in south-western Australia.

There are no biological data for blue swimmer crabs in Shark Bay, where the fishery is developing and has great potential. Shark Bay is located at a far more northern latitude than the Peel-Harvey Estuary and Cockburn Sound, and is characterised by far warmer water temperatures. Furthermore, there are essentially no estuaries near Shark Bay, which means that this type of area which is often used as a nursery ground is not available to this portunid in the region of Shark Bay. The presence of far warmer temperatures in Shark Bay, which will presumably influence the activity, feeding, growth and reproductive biology of this species (see e.g. Hill, 1980; Sukumaran & Neelakantan, 1996), together with the type of environment found in that region, mean that it would be very dangerous to extrapolate from the results of studies further south in temperate Western Australia, or indeed from elsewhere in Australia.

It should be noted that the biological data produced by this proposal will complement a separate study of the dynamics of the fishery (both commercial and recreational) and exploitation of the series of stocks which contribute to the catch of blue swimmer crabs in Western Australia. This project proposal by the Fisheries Department Research Division, will be submitted to the FRDC in December 1997 for the 1998/99 round of grant proposals.

References

Hill, B.J., 1980. Effects of temperature on feeding and activity in the crab Scylla serrata. Marine Biology 59: 189-192.

Penn, J.W., 1977. Trawl caught fish and crustaceans from Cockburn Sound. Rep. Dep. Fish. Wildl. West. Aust. 20: 1 24

Potter, I.C., P.J. Chrystal & N.R. Loneragan, 1983. The biology of the blue manna crab
Portunus pelagicus in an Australian estuary. Mar. Biol. 78: 75 85.

Sukumaran, K. K. & B. Neelakantan, 1996. Relative growth and sexual maturity in the marine crabs, Portunus (Portunus) sanguinolentus (Herbst) and Portunus (Portunus) pelagicus (Linnaeus) along the southwest coast of India. Indian J. Fish. 43: 215-223.

Objectives

1. The main overall objective is to determine those biological parameters for blue swimmer crabs in selected water bodies in south-western Australia and in Shark Bay that are crucial for undertaking stock assessment necessary to develop management arrangements for this crustacean in those two regions.
2. Determine the habitat types occupied by the blue swimmer crab in the marine and estuarine environments in which it is relatively abundant in south-western Australia, and the way in which the habitat requirements change with body size and state of maturity.
3. Determine the age and size compositions and growth of populations of blue swimmer crabs in different water bodies in south-western Australia (Leschenault Estuary, Koombana Bay, Peel-Harvey Estuary, Comet Bay and Cockburn Sound).
4. Determine the size and age composition, growth rates, size of maturity and reproductive season of blue swimmer crabs in Shark Bay.
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