Fisheries Infosite

Environmental Issue

 Deepwater (squid) trawl - NZ sea lion accidental capture

The Auckland Islands are the main breeding colony for New Zealand sea lions. These animals hunt squid in the same areas and same time of year that the southern squid trawl fishery operates, and sometimes get caught in squid trawls.
New Zealand sea lions are a protected species, and listed by the Department of Conservation as 'Range Restricted'. The risk to the sea lion population from fishing activity is not thought to be significant. However, there are some uncertanties around this.
Extent of the issue
Southern squid trawl is a significant fishery, with a number of large vessels operating in it. We have good observer coverage in this fishery and a reasonable idea of how often sea lions end up in trawl nets. Sea lions also occasionally get caught in trawls for southern blue whiting and scampi.
Use of the Sea Lion Excluder Device (SLED) in the southern squid trawl fishery has increased the number of sea lions escaping from squid trawls and surviving. However, the number of pups born at the Auckland Islands has fallen by half from 1998-2008. Some of this decline is thought to be from disease outbreaks.
Current management
The squid trawl fishery has interactions with a range of protected species, most notably seabirds, sea lions and on occasion fur seals. Mitigation measures are in place to reduce seabird interactions. These include the mandatory requirement for all trawl vessels to deploy bird scaring devices such as tori lines or brady bafflers when fishing gear is deployed. In addition all trawl vessels larger than 28m in length are required to have a vessel management plan which sets out the vessel-specific measures a vessel and its crew should follow to avoid seabird interactions. These measures include ensuring there is good factory cleanliness, managing offal discards and making sure that all fish scraps have been removed from the fishing gear before it is put back in the water. Mitigation measures are also in place for marine mammals through the industry-initiated marine mammal operating procedure - this procedure sets out the measures that vessels should follow to make sure that vessels do not have any incidental captures of marine mammals.

A marine reserve around the Auckland Islands means no fishing is allowed within 12 nautical miles (22 km. The foraging range of sea lions that inhabit the Auckland Islands overlaps the fishing grounds of the SQU6T fishery and sometimes trawlers targeting squid catch sea lions. Management intervention is required to manage the effects of fishing on the sea lion population. Each year the Minister of Fisheries sets a limit on the number of sea lions that can be killed in the SQU6T fishery. Because actual mortality can not be assessed performance against this limit is estimated using an estimate of possible sea lion mortality per 100 tows. When the number of tows matches the sea lion catch limit then the fishery is closed. For the 2008-09 squid season the limit was set at 113 sea lions. In recent years the fishing industry, with the support of the Ministry of Fisheries, has developed escape devices (known as sea lion exclusion devices (SLEDs), which are fitted to the trawl net to allow sea lions to swim out of the net if they get caught. The SQU6T fishery also interacts with seabirds which are killed because they either get struck by the warps (large birds such as albatross) or caught in the net when the gear is being shot or hauled (small birds). As in other fisheries a combination of mandatory mitigation measures, such as deploying bird scaring devices at the back of the boat, and vessel specific measures to manage offal discards are in place to reduce the number of fatal interactions.  
Future management
Continuation of current management. A population management plan for New Zealand sea lions is being prepared by the government. 
Documents / links
Science Plenary, Dragonfly, Breen & Kim 2006, DOC [], SQU6T operating Proceedure and FAP consultations 2008.