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Project details
| Title: | Trophodynamics of the south-east trawl deep-water stock (FIRDC project no. 91/17) 1991-1995 |
| Id: | 202 |
| Acronym: | South-East Trawl Trophodynamics Study |
| Investigator(s): | John Parslow
CSIRO Oceans & Atmosphere - Hobart [details] |
| Description: | FRDC project 91/17, entitled "Trophodynamics of the south-east trawl deep-water stock", was designed to improve understanding of the ecological basis of the deep water stocks fished in the south-east trawl (SET) on the continental slope in Tasmanian waters, in particular the food chain supporting the fishery for orange roughy (Hoplostethus atlanticus). 4 seasonal cruises were undertaken on FRV "Southern Surveyor" between July 1991 and April 1993 to measure physical, chemical and biological variables (including chlorophyll and primary productivity) along three sections oriented onshore to offshore. The results were compared with satellite imagery of sea surface temperature acquired over a longer and more detailed period to interpolate the in situ data and to study interannual variability. Additional sampling was undertaken using moored and free-loating sediment traps to study vertical fluxes in the water column. |
| Years: | 1991 to 1995 |
| Hierachy: | Temperate and Deepwater Fisheries Resources » Biomass Assessment and Ecosystem Structure » Ocean Colour |
Data
- Hoplostethus atlanticus (Orange Roughy) length weight data, Australian waters (1987-2012) [IPT: csiro_orange_roughy_length_weight] - at OBIS
List of surveys that this project was on. Click on column header to sort.
Use [details] link to view survey details (map, reports, metadata etc) including links to download data.
| Survey | Investigator | Description |
|---|---|---|
| SS 03/93 [details] |
F.B. Griffiths (CSIRO) | Southern Surveyor cruise SS 03/93 was the fourth (autumn) in a series of four cruises to examine the productivity of the mid-slope region near Pedra Branca, off southern Tasmania, and the processes supporting the rich commercial fisheries. Cruise objectives include demersal fish, micronekton and zooplankton sampling to determine the vertical distribution and diurnal movements; examine the diet of the main fish and zooplankton species at the site through stomach content and stable isotope analyses; determine water mass structure in the sampling area by making cross-slope CTD transects; measure zooplankton biomass, primary productivity and the concentration of chlorophyll-a at the trawl site and the cross-slope transects; study currrents at the Pedra Branca site, by retrieving a current meter mooring and refurbishing and redeploying; investigate the flux of detritus through the water column by deploying moored and free-floating sediment traps; test and calibrate the lightweight towed body containing acoustic equipment for biomass estimation and estimate the vertical biomass distribution and its daily vertical flux through the water column, using acoustic techniques in conjunction with net sampling. |
| SS 04/92 [details] |
J.A. Koslow (CSIRO) | Southern Surveyor cruise SS 04/92 was the third (spring) in a series of four cruises. Leg 1 examined the productivity of the mid-slope region near Pedra Branca, off southern Tasmania, and the processes supporting the rich commercial fisheries. Cruise objectives include sampling of demersal fish, micronekton and zooplankton to determine the vertical distribution and diurnal movements; examine the diet of the main fish and zooplankton species at the site through stomach content and stable isotope analyses; determine water mass structure in the sampling area by making cross-slope CTD transects; measure zooplankton biomass, primary productivity and the concentration of chlorophyll-a at the trawl site and the cross-slope transects; study currrents at the Pedra Branca site, by retrieving a current meter mooring and refurbishing and redeploying; investigate the flux of detritus through the water column by deploying moored and free-floating sediment traps and estimate daily patterns of the vertical distribution of the biomass by using acoustics in conjunction with net sampling. Leg 2 carried out acoustic surveys of midslope fishes and focussed on developing acoustic and net sampling methods of assessing community composition and biomass with particular reference to the deep water fisheries off southern Tasmania. Also during the cruise three satellite-tracked drifters were released for Division of Oceanography. |
| SS 03/92 [details] |
J.A. Koslow (CSIRO) | Southern Surveyor cruise SS 03/92 (in conjunction with two chartered fishing vessels "Petuna Endeavour" & "Petuna Explorer") was undertaken to conduct acoustic surveys and biological sampling of the orange roughy on their spawning ground off north eastern Tasmania (St. Helens area) and also for the blue grenadier off the west coast of Tasmania from Low Rocky Point to southwest of King Island. Demersal, midwater and pelagic trawls, egg incubation and buoyancy experiments, TS measurements and CTD sampling were carried out. Flesh and liver samples of orange roughy at reproductive stage IV were obtained. |
| SS 01/92 [details] |
J.A. Koslow (CSIRO) | Southern Surveyor cruise SS 01/92 was undertaken to conduct the first acoustic survey of orange roughy (Hoplostethus atlanticus) and deepwater oreos, smooth oreo (Pseudocyttus maculatus) and black oreo (Allocyttus niger), on the major deepwater fishing ground off southern Tasmania (leg 1), and then to form the second in a series of four cruises to examine the mid-slope productivity of this area (leg 2). Target strength (TS) measurements, zooplankton, midwater and demersal sampling, pigment analysis, and measurements of primary production and hydrology were taken. |
| SS 02/91 [details] |
J.A. Koslow & J. Young (CSIRO) | Southern Surveyor cruise SS 02/91 was undertaken to conduct mid-slope productivity studies and acoustic surveys off the south and east coasts of Tasmania during leg 1 and 2 of the cruise. Leg 3 of the cruise was undertaken to investigate the biological production and oceanography of the tuna fishing area east of Tasmania. During this part of the cruise a satellite buoy was deployed for the Division of Oceanography. |