Tag Archives: tuna

The amazing longfin eel

This week the Parliamentary Commissioner for the Environment released a report on the status and management of the longfin eel. It was entitled “On a pathway to extinction?” The report found that the management of longfin eels by New Zealand government agencies was inadequate and failing. It further recommended the cessation of commercial fishing of longfin eels.

The Commissioner’s report.

A longfin eel.  This female hasn't bred yet, and she will do so only once, after swimming to somewhere between New Caledonia and Fiji.  Photo (c) Alton Perrie.

A longfin eel, in a stream near Thames. This female hasn’t bred yet, and she will do so only once, after swimming to somewhere between Fiji and New Caledonia. Photo (c) Alton Perrie.

Longfin eels (Anguilla dieffenbachii; tuna is Maori for eel) are amazing animals. They breed only once and then die. The adults found in New Zealand’s waterways have yet to breed. When mature, which may take 80 years, they swim to somewhere between Fiji and New Caledonia to find a mate. The prospect of finding a mate in a far-flung ocean presumably becomes less likely as numbers decline because of human impacts. After breeding, the adults die. The young larvae then drift back to New Zealand, and make their way upriver. The amount of suitable habitat for eels in New Zealand is now much decreased.

The Commissioner highlighted this unusual lifecycle as complicating the management of eels.

The Department of Conservation rates the threat status of longfin eel as “At Risk/Declining”, while the Ministry for Primary Industries allows the annual commercial harvest of more than 100 tonnes of longfin eel. The inability to reconcile these two facts is at least partially behind the Commissioner’s call to stop the commercial fishing of longfin eels.

Earlier this year, Te Papa’s NatureSpace hosted the Travelling Tuna Tapestry project.  The aim of this project was to inspire children to be interested in the conservation of the longfin eel. The tapestry grew during its travels around New Zealand as children contributed panels; one panel came from visitors to NatureSpace.

A Department of Conservation site about the Travelling Tuna Tapestry.

Many New Zealanders will be concerned that an endemic New Zealand species is effectively being managed to extinction. According to the commissioner, “Longfin eels need urgent help from the agencies that are responsible for their management and protection.” How will those agencies respond? Will they do enough to get the longfin eel off its pathway to extinction?

Fish and birds in Tokyo

Work at the fisheries Convention on the Conservation of Southern Bluefin Tuna meeting on bycatch and ecological effects of fishing has progressed in Tokyo in March. The group met to consider ways of reducing seabird, turtle and shark bycatch in fishing for southern bluefin tuna around the southern Ocean.

Albatross and petrel bycatch remains a tricky issue for the management of tuna fisheries, with many birds annually killed in longline fisheries due to their being captured on fishing hooks. Around 3 billion tuna hooks are set annually, and albatrosses captured may number up to 100 thousand annually. Incidental mortality in tuna fisheries affects many seabird species, many of which are threatened with extinction.

See BirdLife Internationals Save-the-Albatross website for source of these statistics

Meeting of specialist on bycatch of seabirds, sharks and turtles at the CCSBT Working Group in Tokyo on 28 - 30 March 2012, at which New Zealand scientists, including Te Papa researchers were participants. Photo: Susan Waugh

Meeting of specialist on bycatch of seabirds, sharks and turtles at the CCSBT Working Group in Tokyo on 28 - 30 March 2012, at which New Zealand scientists, including Te Papa researchers were participants. Photo: Susan Waugh

A report commissioned by the Ministry of Fisheries, and prepared by Te Papa scientists and collaborators was presented. The report discussed how data on seabird distributions, fishing data, and information about bird-catch rates could be used to identify which areas and times of fishing were most problematic for tuna fishing in the Indian and Pacific Ocean areas. The study used data and methods developed over many years with collaborating parties BirdLife International and Sextant Technology, along with inputs from the Agreement on the Conservation of Albatrosses and Petrels (ACAP), the Ministry of Fisheries, NIWA, Centre Nationale de la Recherche Scientifique in France and a number of seabird researchers nationally and internationally.

A figure from seabird ecological risk assessment analyses indicating the density per square kilometre of species around the Southern Ocean. This shows a high density particularly in the New Zealand area. The study presented by Te Papa researchers and collaborators to the Convention for the Conservation of Southern Bluefin Tuna working group examined which areas and species were most at risk of adverse effects of longline fishing for tuna. Image: after Waugh et al. 2012.

A figure from seabird ecological risk assessment analyses indicating the density per square kilometre of species around the Southern Ocean. This shows a high density particularly in the New Zealand area. The study presented by Te Papa researchers and collaborators to the Convention for the Conservation of Southern Bluefin Tuna working group examined which areas and species were most at risk of adverse effects of longline fishing for tuna. Image: after Waugh et al. 2012.

The CCSBT working group agreed to continue work on this project, and will seek to refine the analyses using the most recent dataset available about bird distributions and fishing activity, including important datasets held by BirdLife International derived from satellite tracking of seabirds.

Tuna for sale in Tsukiji market in Tokyo, March 2012. Photo: Susan Waugh.

Tuna for sale in Tsukiji market in Tokyo, March 2012. Photo: Susan Waugh.

By Susan Waugh, Senior Curator Natural Environment

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