PROJECT NUMBER
•
2012-024
PROJECT STATUS:
COMPLETED
ORGANISATION:
CSIRO Oceans and Atmosphere Hobart
SPECIES
49 results
PROJECT NUMBER
•
2007-017
PROJECT STATUS:
COMPLETED
ORGANISATION:
CSIRO Oceans and Atmosphere Hobart
PROJECT NUMBER
•
2006-008
PROJECT STATUS:
COMPLETED
ORGANISATION:
CSIRO Oceans and Atmosphere Hobart
TAGS
PROJECT NUMBER
•
2014-024
PROJECT STATUS:
COMPLETED
Estimating the abundance of School Shark in Australia using close kin genetic methods
Close kin mark recapture (CKMR) provides an estimate of absolute abundance that is independent of fishing behaviour. We present a first CKMR estimate of abundance for School Shark and discuss the management implications of our findings.
We found 65 half sibling pairs (HSPs), 3...
ORGANISATION:
CSIRO Oceans and Atmosphere Hobart
SPECIES
PROJECT NUMBER
•
1999-108
PROJECT STATUS:
COMPLETED
ORGANISATION:
CSIRO Oceans and Atmosphere Hobart
SPECIES
PROJECT NUMBER
•
2009-012
PROJECT STATUS:
COMPLETED
ORGANISATION:
CSIRO Oceans and Atmosphere Hobart
SPECIES
PROJECT NUMBER
•
1995-014
PROJECT STATUS:
COMPLETED
Indices of recruitment and effective spawning for tiger prawns stocks in the Northern Prawn Fishery
In the mid to late 1980s NORMAC began to suspect that tiger prawn spawning stocks in the NPF may have been reduced by fishing to levels that reduced recruitment to the fishery. A vessel buy-back scheme and other effort reductions were introduced to reverse this trend but, by the mid-1990s, the...
ORGANISATION:
CSIRO Oceans and Atmosphere Hobart
PROJECT NUMBER
•
2003-044
PROJECT STATUS:
COMPLETED
Development of a sustainable industry-based observation system for blue grenadier at the primary spawning sites
Blue grenadier has the highest current TAC among SEF species and has two separate fisheries that target primarily either sub-adult fish year-round or mature adults in winter spawning aggregations. The sustainability of the fishery would be greatly enhanced with regular (sustained) monitoring of...
ORGANISATION:
CSIRO Oceans and Atmosphere Hobart
SPECIES
PROJECT NUMBER
•
1997-105
PROJECT STATUS:
COMPLETED
Growth, mortality, movements and nursery habitats of red-legged banana prawns (Penaeus indicus) in the Joseph Bonaparte Gulf
This project has contributed to the ecologically sustainable management of the Northern Prawn Fishery (NPF) by providing information on the status of red-legged banana prawn stocks and the nursery habitats that support this fishery. It has achieved these outcomes by firstly completing detailed...
ORGANISATION:
CSIRO Oceans and Atmosphere Hobart
SPECIES
Development of acoustic methods to survey orange roughy in the eastern and southern zones
Project number:
1995-031
Project Status:
Completed
Budget expenditure:
$144,588.00
Principal Investigator:
Tony Koslow
Organisation:
CSIRO Oceans and Atmosphere Hobart
Project start/end date:
20 Sep 1995
-
5 May 1999
Contact:
FRDC
1. Conduct 2-3 acoustic surveys of orange roughy spawning ground off St Helens, TAS during the peak spawning period 1995
2. Determine the species composition of acoustic marks through trawl sampling of the acoustic marks and the ensonification of targets with several frequencies
3. Determin the relative biomass and spawning condition of orange roughy in the Eastern and Southern zones during the spawining period based upon a survey of selected hills in the Southern Zone that contain the principal concentration of orange roughy
4. Assess the biomass of orange roughy in the area between St. Helens and the Southern Hills through a series of zig-zag transects between 700-1200m and to assess their spawning condition
Final report
ISBN:
0643 06191 6
Author:
Tony Koslow
Final Report
•
1999-04-09
•
9.30 MB
1995-031-DLD.pdf
Three acoustic surveys were carried out between 17 and 20 July 1996 on the orange roughy spawning ground off St. Helens, Tasmania. A combination of 22 demersal trawls and ensonification with three frequencies (12, 38 and 120 kHz) was used to assess the species composition around the spawning hill. Both methods showed that orange roughy were aggregated on only the north/northwestern half of the hill. Acoustic marks on the south/southwestern sector of the hill were composed predominantly of macrourids (rattails) and deepwater cods. This was the first successful use of multi-frequency acoustics to discriminate among species groups in a deepwater environment and should greatly enhance the resolution of deepwater acoustic surveys. Acoustic estimates of orange roughy biomass on the spawning hill ranged from 5649 - 9706 tonnes, down from 16,777 tonnes in 1993. A survey of the trawl ground off St. Patrick's Head noted a single moderate-sized aggregation on a single transect.
If the school as assumed to be spherical in cross-section, its biomass was 6% the biomass of the largest orange roughy school observed at St. Helens. The biomass at St. Patrick's Head thus appears to have been a small proportion of the biomass around St. Helens Hill during the survey, but the data were insufficient to derive a biomass estimate from this area with confidence. Acoustic surveys were also carried out on a small hill just north of St. Helens and on the seamounts in the Southern Zone but no significant acoustic marks associated with orange roughy were observed in these areas.
Several changes were made to the methods of analysis. First, the area of the strata comprising the St. Helens hill were re-calculated based on improved bathymetric and GPS data,. Secondly, we changed the method used to account for targets within the deep scattering layers (DSL) that extend across the survey area. A constant fraction of the ensonified targets were previously assumed to belong to the DSL, but this assumption was no longer tenable considering both the decline in orange roughy abundance on the hill and the ~2-fold variation in the abundance of midwater scatterers between surveys in 1996. Acoustic backscattering from areas outside the survey area were now measured for each survey and subtracted from the backscattering observed around the hill itself. These changes were applied retrospectively to biomass estimate from previous orange roughy surveys.
