4,221 results

In situ time-stamping of abalone shells to determine how abalone stocks can be aged.

Project number: 1995-004
Project Status:
Completed
Budget expenditure: $249,980.00
Principal Investigator: Robert W. Day
Organisation: University of Melbourne
Project start/end date: 12 Jul 1995 - 14 Sep 2002
Contact:
FRDC

Objectives

1. This project will determine the timing and regularity of the calcite layers deposited under the spire of abalone shells, through extensive field based tagging and "timestamp" marking of abalone.
2. We propose to achieve objective 1 for populations of blacklip abalone at three sites in Victoria, three sites in Tasmania and one site in New South Wales
and also for populations of greenlip abalone at two sites in South Australia.
3. We aim to determine how to interpret the layers in abalone shells, how reliable such interpretations are, and how layer formation may vary between localities.
4. We will use this information to determine the age distribution of abalone at a number of sites.
5. We aim to be able to predict where and how layers can be used to age abalone in stocks in Southern Australia.

Final report

ISBN: 0-7325-1616-1
Author: Rob Day
Final Report • 2002-01-25 • 933.56 KB
1995-004-DLD.pdf

Summary

If abalone can be accurately aged, this would be a fundamental tool for more effective management of abalone fisheries.  Several authors have proposed ageing abalone by grinding or cutting abalone shells, and counting the shell layers deposited beneath the spire.  Other authors have cast doubt on this method.  What is uncertain is how reliable these age estimates are.  To construct useful models to assess and manage abalone stocks, it is important to know the accuracy of the data on which the model is based.  Furthermore, it is labour intensive to collect age data, and if these data are very inaccurate, then resources are wasted in collecting it.

This project aimed to find out how reliable and accurate the ageing method was, by investigating the timing and the periodicity of layer formation in abalone shells. It seemed possible that the ageing method might work reasonably in some areas, but not in others.  Thus we planned to repeat the work at many places in the hope that we could predict where ageing would be useful for managing the blacklip and greenlip abalone fisheries of Victoria, Tasmania, New South Wales and South Australia.

Project products

Scientific publication • 683.36 KB
1995-004-PDT-1.pdf

Summary

Ionoluminescence (IL) combined with particle induced X-ray emission (PIXE) imaging has been employed to identify intrinsic growth bands in the spire region, and extrinsic bands at the growth edge of Australian Black-lip abalone shell (Haliotis rubra). Previous studies using optical flood cathodoluminescence, scanning electron microscope cathodoluminescence (SEM-CL) and Raman spectroscopy on samples from the same population suggest that the visible luminescence is due to Mn2+ activated calcium carbonate. In this study we confirm Mn2+ as the activator in both the spire and growth edge regions of the shell.

Scientific publication • 2001-01-05 • 2.13 MB
1995-004-PDT-2.pdf

Summary

Boring predators and epibionts often damage the shells of molluscs. In abalone, spionid polychaete worms bore holes into the shell and live within the shell matrix (Shepherd and Huchette, 1997). Shepherd and Huchette (1997) found that these worms can infest entire populations, severely weakening the shells of some individuals which can lead to mortality. Given the potential consequences of boring attacks, do abalone show any response these attacks?

Environment
Environment
PROJECT NUMBER • 1994-029
PROJECT STATUS:
COMPLETED

A collaborative investigation on the usage and stock assessment of bait fishes in southern and eastern Australian waters, with special reference to pilchards (Sardinops sagax neopilchardus)

This project was initiated in response to a rapid increase in the demand for pilchards and other baitfish species and the subsequent expansion of purse-seine fisheries throughout southeastern Australia. During the course of the proj ect, the need for research on pilchard stocks was further increased...
ORGANISATION:
SARDI Food Safety and Innovation
Environment
PROJECT NUMBER • 1981-049
PROJECT STATUS:
COMPLETED

Assessment of the Norfolk Island domestic fishery with a study on the major species, sweetlip emperor (Lethrinus chrisostumus)

The Norfolk Island domestic fishery survey was undertaken by Department of Primary Industry (DPI), Canberra on behalf of the Norfolk Island Legislative Assembly. Research undertaken on Norfolk Island during 1981 to 1983 was funded by the Fishing Industry Research Trust Account (FIRTA 81/49) with...
ORGANISATION:
Department of Agriculture Fisheries and Forestry
Environment
PROJECT NUMBER • 2003-003
PROJECT STATUS:
COMPLETED

Spawning and reproductive characteristics of Bight redfish and deepwater flathead in the Great Australian Bight trawl fishery

This project addressed some of the important information gaps identified during assessment workshops for Bight redfish and deepwater flathead. Improved stock assessments, which incorporate the latest biological parameters (size-at-maturity, fecundity and sex ratio), has lead to the setting of...
ORGANISATION:
Agriculture Victoria
Environment
PROJECT NUMBER • 2012-008
PROJECT STATUS:
COMPLETED

Assessing the impact of marine seismic surveys on southeast Australian scallop and lobster fisheries

The present study, undertaken by University of Tasmania’s Institute for Marine and Antarctic Studies in conjunction with Curtin University’s Centre for Marine Science and Technology, was developed to investigate the potential impact of seismic surveys on economically important fishery...
ORGANISATION:
University of Tasmania (UTAS)
Environment
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