Malcolm Clark and Richard O'Driscoll
National Institute of Water and Atmospheric Research
P. O. Box 14-901, Wellington, New Zealand
Source - Journal of Northwest Atlantic Fishery Science, Volume 31: 441-458
Deepwater fisheries for orange roughy (Hoplostethus atlanticus) and oreos (Pseudocyttus maculatus) in New Zealand waters have been established for 20-30 years. Over time the fisheries have become more focused on seamounts, where aggregations of the fish can occur for spawning or feeding. The catch of orange roughy in particular from these features has increased from about 30% of the total catch in 1985 to 80% by 1995, and has since stabilized at 60-70%. There has been active searching for seamount habitat, and by 2000 about 80% of known seamounts in the appropriate depth range had been fished. In New Zealand there are widespread concerns that seamount habitat needs to be managed carefully. In May 2001, 19 seamounts were given some protection through a ban on bottom trawling.
Heavy bottom trawl gear is known to have a direct physical effect on the seabed. Seamounts are often small in size, and trawling can rapidly become concentrated in a very localized area. Seamount habitat is thought to be productive, but may also be fragile, and there is growing concern about effects of fishing on biodiversity and ecosystem productivity. In this paper we report on ongoing research to examine the extent of impact on seamount habitat. Detailed fisheries data were analysed to determine the numbers and distribution of individual trawls on seamounts to measure how intensive trawling has been. Photographic surveys of the seafloor and mapping the distribution of benthic fauna have also been carried out to quantify the area of seamounts impacted by trawl gear. Comparisons have been made between heavily-fished and unfished seamounts.
Language - English
Publisher - Northwest Atlantic Fisheries Organization (NAFO), Dartmouth, N.S., Canada
Publication Date - 2003
Publication Type - Journal Article
Descriptors - conservation, deepwater fisheries, fishing importance, New Zealand, orange roughy, seamounts, trawling impacts