Is current management of the Antarctic krill fishery in the Atlantic sector of the Southern Ocean precautionary?

Summary

This study examines whether current Antarctic krill fishing management in the Atlantic sector of the Southern Ocean is precautionary - meaning it protects the krill population from overfishing. The analysis shows that current management is working well at the regional scale.The effective catch limit (trigger level) of 0.62 million tonnes per year represents an exploitation rate of less than 7% of estimated krill biomass - below the 9.3% level considered sustainable for maintaining healthy krill stocks and supporting dependent predators.Subarea catch limits help prevent excessive concentration of fishing in any one area. The research concludes that while current management is precautionary regionally, more detailed monitoring and management at smaller scales will be important for protecting this crucial Antarctic ecosystem.

Key Findings

Trigger level catch limit (0.62 million tonnes) represents ~1% of the 2000 biomass estimate

Exploitation rates in each subarea remain below 3% due to actual catches being less than 50% of the trigger level

No evidence for krill decline in recent decades, despite some decline in the 1980s

Current management appears precautionary at the regional scale, but finer-scale management may be needed for sensitive areas and climate change impacts

Abstract

This paper explains the management of the Antarctic krill (Euphausia superba) fishery in the Atlantic sector of the Southern Ocean, and current knowledge about the state of the regional krill stock. In this region, krill fishing is permitted in an area of approximately 3.5 million km² which is divided into four subareas (labelled Subareas 48.1 to 48.4) for management and reporting purposes. The effective regional catch limit (or 'trigger level'), established in 1991, is 0.62 million tonnes year⁻¹, equivalent to ~1% of the regional biomass estimated in 2000. Each subarea has also had its own catch limit, between 0.093 and 0.279 million tonnes year⁻¹, since 2009. There is some evidence for a decline in the abundance of krill in the 1980s, but no evidence of a further decline in recent decades. Local-scale monitoring programs have been established in three of the subareas to monitor krill biomass in survey grids covering between 10,000 and 125,000 km². Cautious extrapolation from these local monitoring programs provides conservative estimates of the regional biomass in recent years. This suggests that fishing at the trigger level would be equivalent to a long-term exploitation rate (annual catch divided by biomass) of <7%, which is below the 9.3% level considered appropriate to maintain the krill stock and support krill predators.

Published in

CCAMLR Science

2016

Authors

Hill, S.L., Atkinson, A., Darby, C., Fielding, S., Krafft, B.A., Godø, O.R., Skaret, G., Trathan, P.N., Watkins, J.L.

Institutions

British Antarctic Survey Plymouth Marine Laboratory CEFAS Institute of Marine Research, Norway

Methods

AcousticBiological sampling Data

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