Science Centres: Fisheries

A strong concentration of echoes from a school of fish above a seamount at 920 m depth. The white band is the seafloor.

NIWA’s deepwater research vessel Tangaroa is conducting back-to-back fisheries surveys for the Ministry of Fisheries this summer. These surveys provide critical information on the stocks to assist with sustainable management.

Tangaroa and the Sanford vessel San Waitaki covered an area of more than 10 000 km2 on the South Chatham Rise in November, surveying smooth oreo. Tangaroa did the acoustic sampling while San Waitaki conducted bottom-trawls to verify the species. The total trawl catch was 332 t, 91 percent of which was smooth oreo, with 93 fish species recorded.

Because estimates of fish abundance from acoustic surveys rely on knowing how much sound bounces off each fish, the survey team also collected data on the relationship between fish size and echo strength.

Tangaroa is now engaged in a combined trawl and acoustic survey of hoki, hake, and ling stocks in the Southland and Sub-Antarctic regions. The data will provide the ninth summer estimate of the ‘western’ hoki stock since 1991.

Tangaroa will head back to the Chatham Rise in late December for a 27-day survey of hoki and other species, the fifteenth survey in this time series.