New seamount research to improve fisheries management

NIWA's research vessel Tangaroa left Wellington on 4 February to survey the seafloor environment of the Louisville Seamount Chain, which are large undersea mountains east of New Zealand. The research is part of a science programme that is investigating the relationship between deep-sea trawling and the diversity of animals that live on the seafloor.

A wide range of animals inhabit the deep-sea, including large corals that can form reefs similar to their shallow-water tropical cousins, as well as sponges, seastars, sea anemones, feather stars and sea pens. Many of these species, and the wider communities they form (ecosystems) are considered vulnerable to the effects of human activities, such as fishing. This has led to calls from as high as the United Nations to implement management strategies to protect these systems (termed "Vulnerable Marine Ecosystems" or VMEs) and thereby preserve ecosystem function in the deep sea.

New Zealand fishing fleets operate in the high seas region of the South Pacific, and New Zealand is currently leading initiatives to improve fisheries management in the region through the South Pacific Regional Fisheries Management Organization (SPRFMO). However, there is currently limited information about the distribution or characteristics of VMEs in the South Pacific, which is hampering the design of management measures. A NIWA science programme funded by New Zealand (through the Ministry of Business, Innovation and Employment and the Ministry for Primary Industries) and involving a team of New Zealand and American scientists, is developing habitat suitability models that we hope can predict the occurrence of seabed animals that indicate the presence of VMEs. This technique uses information on the known occurrence of species, and their associated environmental conditions, to extrapolate into unknown areas and estimate the likelihood of environmental conditions being suitable for the species.

Model results to date appear to be good, but such predictions need to be ground-truthed to give scientists and end-users (e.g., the SPRFMO Scientific Committee) confidence in their application for management purposes. Thus a critical component of the VME project has been to design and implement a survey to evaluate the reliability of the VME models. The survey will take place on the Louisville Seamount Chain (more on that next time), where the VME models indicate there may be areas of extensive deep-sea coral habitat, as well as other VME taxa, and also species that have never been seen before.

Malcolm Clark, Ashley Rowden
NIWA

The NIWA research vessel Tangaroa in port in Wellington the evening/morning before sailing for the survey. [NIWA]
The NIWA research vessel Tangaroa in port in Wellington the evening before sailing for the survey. [NIWA]
A patch of deep-sea stony coral and sea stars on a small seamount near the Chatham Islands at 1000m depth - this is the type of habitat that scientists expect to find on the Louisville seamounts. [NIWA]