307 results
Environment
Environment
PROJECT NUMBER • 2003-041
PROJECT STATUS:
COMPLETED

Estimation of natural and fishing mortality using length composition data

The objectives of this project were to develop length-based approaches for estimation of natural, fishing and total mortality, and to explore the application of these methods to the data from selected fisheries. The methods that were developed were essentially length-based versions of age-based...
ORGANISATION:
Murdoch University
Environment
PROJECT NUMBER • 2001-029
PROJECT STATUS:
COMPLETED

Studies of the growth and mortality of school prawns

Information about growth and mortality are important in the management of resources because these provide us with an understanding about the productivity of the target population. Estimates are used to assess the impact of fishing upon the target population and the effectiveness of various scenarios...
ORGANISATION:
Department of Primary Industries and Regional Development (NSW)
Industry
PROJECT NUMBER • 2019-147
PROJECT STATUS:
COMPLETED

Risk factors and management strategies associated with summer mortality in Australian abalone

In this project, we reviewed the scientific literature and collaborated with Australian abalone growers to develop a case definition for summer mortality. The case definition developed for summer mortality is as follows: i. Chronic mortality of unknown cause (if in doubt take this to mean...
ORGANISATION:
University of Adelaide
Environment
Environment

Workshop to facilitate epidemiological analysis of unexplained mortality of South Australian Pacific Oyster

Project number: 2012-051
Project Status:
Completed
Budget expenditure: $36,000.00
Principal Investigator: Charles Caraguel
Organisation: South Australian Oyster Research Council Pty Ltd (SAORC)
Project start/end date: 16 Sep 2012 - 31 Mar 2013
Contact:
FRDC

Need

For at least the last 12 years SA growers have noticed unexplained mortality of Pacific Oysters. Tests for Pacific Oyster Mortality Syndrome (OHSV-1uvar) have come up negative each time.

The mortality was first documented in Smokey Bay and is now documented in all the major producing Bays in South Australia, including Coffins Bay, Smoky Bay, Cowell and Ceduna (Denial Bay). Mortality rates have been increasing over time. Losses of between 5-20% each year which equates to between $1.8-$7 million per annum.

Mortalities are generally associated with seasonal temperature related stress in the animals. The timing of the mortalities varies from year to year within specific bays. Mortlaities do not follow a geographical distribution with some sites more affected than others. Anacodatal advice from growers indicates that sites with slower growth rates don’t suffer as badly has highly productivity bays.

In recent years, mortalities have been experienced in the major producing bays. Anacdotal adivce from growers indicates that mortality is particularly in smaller to medium size oysters, but mortality is also occuring in mature stock.

There does seem to be a genetic link to the mortality with anacdotal reports of 100 % mortality of certain “batches”. Given this link the breeding program is breeding for resistance to these unexplained mortality events. Susceptibility varies depending on the family line.

In response some growers are lifting the height of the oysters which reduces the mortlaity rate but slows the growth rate and increases the growout time. There is concerm within the industry that this is not an economically viable solution in the long term.

Research has been proposed to investigate unexpained mortality however industry are supportive of an epidemiological analysis of exisiting data and knowledge to narrow the likely causes so that any future research is focused on likely causes.

Objectives

1. Bring together growers and epidemiologists to define, describe and quantify the scope of unexplained mortality of Pacific Oysters in South Australia
2. Develop and test range of hypothetical causes of the mortalities based on best available information and expertise
3. Identify any gaps in the knowledge or expertise required to test the hypothetical causes
4. Refine and seek agreement on a future Research and Development plan that addresses unexplained Pacific Oyster mortality in South Australia
Environment
Environment
Environment
PROJECT NUMBER • 1995-020
PROJECT STATUS:
COMPLETED

Mortality, growth and movements of the western rock lobster, Panulirus cygnus

The very high levels of exploitation in the western rock lobster fishery have resulted in the introduction of regional or zone-specific management arrangements in recent years. This is a permanent departure from an holistic approach to the fishery’s regulation. A detailed knowledge of...
ORGANISATION:
Department of Primary Industries and Regional Development (DPIRD) WA
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