Voyage report for estimates of biomass of orange roughy spawning aggregations in ORH3B NWCR and ESCR management sub-areas in June-July 2016 using a net attached acoustic optical system

[摘要] From June 18th to July 15th 2016 a series of acoustic and biological survey activities were carried out to quantify orange roughy biomass during the winter spawning events in the Northwest Chatham Rise (NWCR) and East and South Chatham Rise (ESCR) fisheries management areas. The primary acoustic survey instrument was a trawl net-attached Acoustic Optical System (AOS), which wastowed at depth to conduct multi-frequency transect surveys. Demersal trawls (with the AOS attached to the net) provided biological samples which were processed to provide speciescomposition and measures of fish length, weight, sex and spawning condition. The AOS-demersal trawls also provided acoustic target strength (TS) information at two frequencies, complemented byvideo and stereo digital still photographs. During AOS surveys the vessel’s calibrated ES60 38 kHz echosounder was running concurrently. A Furuno FCV 30 triple beam echosounder was occasionally used during searches for fish to take advantage of the increased areal coverage provided by the sidelooking echosounder beams. This report summarises the voyage activities, data obtained and gives a brief overview of observations made at each of the survey locations. A full analysis of the acoustic data with biomass estimates of orange roughy will be reported as the next project deliverable in February 2017.

[发布日期] 2016-08-02 [发布机构] CSIRO

[学科分类] 地球科学(综合)