33 results
Environment
Environment
PROJECT NUMBER • 1998-205
PROJECT STATUS:
COMPLETED

Construction and evaluation of an underwater setting device to prevent accidental capture of seabirds on tuna longliners

Longline fishing is one of the world's major methods of catching fish (Lokkeborg 1999). Some seabirds, particularly albatrosses and petrels have learnt to take bait from longlines while the lines are being set and when doing so put themselves at risk. If they either swallow the hook or become...
ORGANISATION:
Parks and Wildlife Service Tasmania
Industry

Fishery-independent estimate of spawning biomass of Southern Bluefin Tuna through identification of close-kin using genetic markers

Project number: 2007-034
Project Status:
Completed
Budget expenditure: $739,660.00
Principal Investigator: Mark Bravington
Organisation: CSIRO Oceans and Atmosphere Hobart
Project start/end date: 31 Mar 2009 - 29 Sep 2012
:

Need

Management of SBT is greatly complicated by large uncertainties in the stock assessment. One key parameter is absolute spawning stock size, for which the only available estimates are highly uncertain and are driven entirely by fishery-derived data (e.g. Japanese CPUE, catches on the spawning ground). Hence, the management procedures being developed for SBt use relative, rather than absolute, abundance indices. Current concerns about historical over-catch, of uncertain magnitude and duration make the conventional stock aseessment even less certain. A fishery independent estimate of standing stock biomass (SSB) provides both a stand alone benchmark to compare with current catches, and a fixed reference point around which to rebuild future assessments. This cannot be done with current fishery independent approaches, such as conventional tagging. However, recent advances in genetic and statistical methods now permit a fishery-independent estimate, using identification of parent-offspring pairs in random samples of juveniles and spawners. The same approach can also provide information on age-specific fecundity and thus on appropriate definition of SSB (spawning stock biomass). This is another area of significant uncertainty for management because, as noted above, the different definitions of SSB have considerably different implications for stock projections and rebuilding times.

An absolute estimate of spawning stock biomass is particularly valuable given the estimated level of depletion of the SBT stock, and the high uncertainty about the productivity of the stock (i.e. the relationship between the parent stock and recruitment). Although this project will initially aim to provide an estimate of average SSB over 2002-2005, it will ultimately provide the methods to enable a time-series of SSB to be estimated if sampling continues. Furthermore, the statistical methods developed and applied in this project will have general applicability to a range of species.

Objectives

1. To provide a fishery-independent estimate of the number of SBT spawners (preliminary estimate ready for CCSBT 2007
precise estimate ready for CCSBT 2008).
2. To provide direct estimates of age-specific fecundity and an improved definition of spawning stock biomass (estimate for CCSBT 2008)
Environment
Industry
PROJECT NUMBER • 2018-194
PROJECT STATUS:
COMPLETED

Forecasting spatial distribution of Southern Bluefin Tuna habitat in the Great Australian Bight – updating and improving habitat and forecast models

This project was a collaboration between CSIRO, the Australian Southern Bluefin Tuna Industry Association (ASBTIA) and the Australian Bureau of Meteorology (BoM). The project aim was to update work done as part of FRDC Project 2012/239 “Forecasting spatial distribution of Southern Bluefin Tuna...
ORGANISATION:
CSIRO Oceans and Atmosphere Hobart
Industry
PROJECT NUMBER • 2017-241
PROJECT STATUS:
COMPLETED

Understanding blood flukes infecting Southern Bluefin Tuna

Cardicola forsteri is the dominant blood fluke species detected in farmed Southern Bluefin Tuna in 2018. Our results have shown that traditional methods (heart flush and gill microscopy) were limited to detecting adults or eggs. Comparisons of currently used diagnostic methods showed that...
ORGANISATION:
RMIT University Melbourne City Campus
View Filter

Species