16 results
Environment
Environment
Environment
Environment
PROJECT NUMBER • 1997-110
PROJECT STATUS:
COMPLETED

Age validation from tagged school and gummy sharks injected with oxytetracycline

The project ‘Age Validation from Tagged School and Gummy Sharks Injected with Oxytetracycline’ (FRDC Project 97/110) follows on from four successfully completed projects. These are the ‘Southern Shark Age Validation’ (FRDC Project 91/037), ‘Southern Shark Nursery’...
ORGANISATION:
Agriculture Victoria
Environment
PROJECT NUMBER • 1996-162
PROJECT STATUS:
COMPLETED

Southern shark tag database

As part of the projects, all available tag release-recapture data available from shark tag releases during 1947-56, 1973-76, and 1990-99 have been validated and consolidated in the Southern Shark Tag Database developed in Microsoft ACCESS. The database is routinely updated and has facility for...
ORGANISATION:
Agriculture Victoria
Environment
Environment
PROJECT NUMBER • 1993-100
PROJECT STATUS:
COMPLETED

Evaluation of methods to assess abalone abundance

The issue of how best to survey abalone populations to obtain estimates of abundance has been the subject of debate among fisheries biologists for many years. In an attempt to resolve this issue we compared and evaluated abalone abundance estimated by the following methods: Transect survey,...
ORGANISATION:
Agriculture Victoria

Port Phillip Bay and Bass Strait scallop research

Project number: 1983-032
Project Status:
Completed
Budget expenditure: $0.00
Organisation: Agriculture Victoria
Project start/end date: 28 Dec 1986 - 31 Dec 1986
Contact:
FRDC

Objectives

1. To define causes and extent of natural fluctuations in population numbers of scallops in Port Phillip Bay
2. determine effects of scallop dredging on aquatic biota of PP Bay
explore ways to optimise scallop yields from PP Bay

Final report

Author: D. Gwyther
Final Report • 1986-12-31 • 5.47 MB
1983-032-DLD.pdf

Summary

During the 3 years of the study, scallop spatfall was observed to occur over a short period (October-December) after the scallops had spawned in spring. Growth was rapid and scallops reached an acceptable harvestable size of 70mm within 16 months. Spatfall one year can therefore be related to recruitment during the next. Years of high and low spatfall were reflected in subsequent differences in recruitment. Though more years' data are required, indices of spatfall provide managers and fishermen with predictive information on likely recruitment strength one year in advance.

Each year the strength of recruitment and the residual stock size were estimated from the results of surveys by SCUBA divers. The results have shown that commercial viability of the fishery is primarily dependent upon recruitment each year. Residual stocks are normally insufficient to support the fishery in the event of poor recruitment.

Estimates of growth and mortality rates determined from tagging and data on seasonal changes in meat yield have been used to develop a mathematical model which can be used to determine number of scallops available each season and yields obtainable from different management strategies. Estimates from annual survey, of stock abundance and mean scallop size at the beginning of each year provide the data for the model.

As a result of the research program, the need to continue monitoring spatfall in Port Phillip Bay and to conduct surveys of recruitment strength each year has been identified. These data are necessary for fisheries managers to maintain the ability to manage the stocks by quota system.

Environment
PROJECT NUMBER • 1995-165
PROJECT STATUS:
COMPLETED

Movement and re-aggregation of blacklip abalone in response to intensive fishing

Typically abalone are found clustered into aggregations of many individuals along gutters and ledges that dissect the surfaces of the reefs they inhabit. Commercial abalone divers take advantage of this clustering behaviour and specifically target aggregations to minimise the time spent searching...
ORGANISATION:
Agriculture Victoria
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