Project number: 1999-111
Project Status:
Budget expenditure: $263,136.09
Principal Investigator: Rudy Kloser
Organisation: CSIRO Oceans and Atmosphere Hobart
Project start/end date: 30 Mar 1999 - 14 Aug 2002


The primary need is to remove the uncertainty surrounding the status of the orange roughy stock by performing a combined CSIRO high precision research vessel and industry surveys of the Eastern zone during the 1999 spawning season. Following reanalysis of available information, most recent assessment indicates reduction of catches by 50% or even closure might be necessarry to meet AFMA's performance criteria for this fishery. However, recent catch and effort data (that is not used in the assessment), recent ageing data, and fisher's observations together suggest that the assessment may no longer accurately represent the population dynamics of the roughy. If these observations can be substantiated by an accepted biomass assessment (requring industry and CSIRO cooperation to get coverage plus precision), the potential savings to the industry are 1000-2000 t quota at say $4/kilo = 4-8 million per year.

There is a second need, to assess the ability of industry sounders to monitor the state of the resource. Industry monitoring of the stock could prove less costly than high precision scientific surveys. However a number of questions remain unanswered regarding industry vessel acoustics precision and sensitivity. Clearly industry-based surveys need to be carried out with calibrated sounders and to conduct biological sampling of fish marks with fin-mesh liners in the codends. However further questions remain regarding the precision that can be obtained from vessel-mounted systems that are susceptible to sea state, vessel noise and stability. To what extent then do industry sounders have the ability to map schools and relative biomass over a given season?

To test the power of the industry sounders requires a controlled experiment. This can be achieved by conducting acoustic surveys simultaneously with the common 28 kHz industry sounders and the scientific 38 kHz vessel-mounted and towed systems. This was attempted in 1996 in an opportunistic manner. However, a logger borrowed from the industry and set up on the Southern Surveyor's 28kHz echo sounder soon failed, so no useful data were collected. A more rigorous attempt to incorporate industry acoustics is required.


1. To assess the biomass of orange roughy based on acoustic surveys on the Eastern Zone fishing grounds during the spawning period using industry vessel acoustics over an extended period and the CSIRO acoustic package during the anticipated peak spawning period.
2. To assess how industry acoustics may be best used in the long term management of the resource.
3. To compare the sensitivity and precision of acoustic surveys using scientific vessel-mounted and towed-body acoustics and industry vessel-mounted acoustics.
4. To further develop the acoustic method by improving the multi-frequency technique for species identification.

Final report

Related research


SESSF Monitoring and Assessment – Strategic Review

1. In consultation with the project Reference Group, SESSFRAG and SEMAC, identify priorities, key concerns, perceived shortcomings and opportunities for improvement in monitoring and assessment arrangements for the SESSF fishery.
Australian Fisheries Management Authority (AFMA)