CCAMLR

The Agreement on the Conservation of Albatrosses and Petrels held the Third Session of its Meeting of the Parties from 27 April – 1 May 2009. Key outcomes of relevance to the Ad Hoc WG-IMAF were the adoption of the Advisory Committee’s Work Programme for 2010-2012 and the granting of approval for the ACAP Secretariat to enter into a Memorandum of Understanding with CCAMLR. The proposed MoU has been submitted as a background document for consideration at CCAMLR XXVIII. There were no meetings of ACAP’s Advisory Committee or its Seabird Bycatch Working Group held since the last meeting of the meeting of the Ad-hoc WG IMAF. However, the Agreement was represented at the Second Joint Meeting of Tuna RFMOs and the outcomes of this meeting of relevance to the work of the Ad-hoc WG IMAF are reported on.

This paper documents recent and ongoing developments in New Zealand’s Exclusive Economic Zone that are relevant to the work of the IMAF working group. The bycatch of seabirds by fisheries within New Zealand’s EEZ in recent years that either breed or forage within the CCAMLR convention area (Convention Area seabirds) is detailed. This paper contains description of the recent and ongoing seabird mitigation trials that are underway in New Zealand. We also briefly report on the ongoing revision of the NPOA-Seabirds which will utilise both Level 1 and Level 2 risk assessment methodologies.

Seabird mortality levels caused by net entanglement in the icefish trawl fishery in Subarea 48.3 became a concern in the late 1990s. At this time there was little knowledge on how to mitigate such mortality. As an interim measures a vessel specific 20‐bird mortality threshold was introduced for Subarea 48.3 in 2001. This provided a strong commercial incentive for industry to develop measures to reduce seabird bycatch levels. This resulted in the development and operational trialing of several measures, including net‐binding and net weighting. Net binding has proved to be a highly effective and simply applied mitigation measure and is thought to be largely responsible for the continued reduction in incidental mortality in the icefish trawl fishery in Sub area 48.3 from 0.26 birds/trawl in 2001 to 0.01 birds/trawl in 2008. Evidence suggests that net weighting and good deck practices to minimise the time that the net is on the water’s surface have been the key factors in reducing seabird entanglements during the haul down from 132 birds in 2005 to single figures in 2007 and 2008. 

Three GLS datasets were added to the BirdLife Global Procellariform Tracking Database in 2008. 

Within the Crozet Islands Exclusive Economic Zone (EEZ), the Patagonian toothfish longline fishery is exposed to high levels of depredation by killer and sperm whales. In this context, this study (i) provides estimations of annual depredation levels on a 5-years period (2003-2008), (ii) proposes operational measures to reduce depredation levels using the current longline fishing technique. From 2003 to 2008, sperm whales alone, killer whales alone, and the two species co-occurring were observed on respectively 32.6%, 18.6% and 23.4% of the 4289 lines hauled out over this period. Over this 5 year period we estimated a total loss of 1200 tons of Patagonian toothfish due to depredation which represents a financial loss of approximately 10 millions €. Killer whales were found to be responsible for the largest part of this loss (70%) while sperm whales had a lower impact (30%). Photo-identification data revealed that among the 97 killer whales interacting with the fishery, however 35 individuals belonging to four different pods were involved in 81.3% of the interaction events. We also estimated that a total of 64 sperm whales interacted with the fishery on the Crozet EEZ in 2008. Significant variations of interaction rates with killer whales were detected between vessels suggesting the influence of operational factors on depredation. When killer whales were absent at the beginning of the line hauling process, short lines (<5000m) provided higher yield and were significantly less impacted by killer whales than longer lines. No differences were found if killer whales were present when hauling started. Based on the analyse of killer whales movements in relation to fishing vessel, when facing depredation we recommend vessels to leave their fishing area and travel on distances greater than 40Nm to prevent killer whales from finding them within few hours. More data are still needed to better understand how killer whales search and detect fishing vessels. In a way to suppress cetacean depredation fish traps will be tested on an experimental campaign which will take place in early 2010.

For operational reasons it would be more convenient to extend the 48.3 fishing season into April rather than into September. A proposal is developed to experimentally allow incremental extensions into April, accompanied by a bird bycatch limit, starting with an allowance for all vessels having full compliance with CM 25-02 in 2009 to fish from 26 April 2010 in the 2009/2010 fishing season. Vessels catching 3 birds in this period would have to stop fishing until 1 May 2010.

Fisheries are increasingly adopting ecosystem approaches to better manage impacts on non-target species. Although deliberate dumping of plastics at sea is banned, not all fisheries legislation prohibits discarding of gear (hooks and line) in offal, and compliance is often unknown. Analysis of a 16 year dataset collected at Bird Island indicated that the amount of gear found in association with wandering albatross colonies was an order of magnitude greater than in any other species, reflecting their wider foraging range and larger gape. Unlike other taxa, most gear associated with grey-headed albatross was from squid and not longline fisheries, and mistaken for natural prey rather than the result of direct interaction. Observed rates of foul-hooking (entanglement during line hauling) were much higher in giant petrels and wandering albatross than black-browed albatross, and no grey-headed albatross was affected. The index of wandering albatross gear abundance showed two peaks, the most recent corresponding with a substantial increase in the number of multifilament snoods (gangions), suggesting that the widespread adoption of a new longline system may have been responsible. Although all identified gear was demersal, given the widespread use of similar hooks, little could be assigned to a specific fishery. Stomach content analysis suggested that 1300-2048 items of gear are currently consumed per annum by the wandering albatross population at this archipelago. Many hooks are completely digested by chicks, long-term effects of which are entirely unknown. We suggest a number of management approaches for addressing the problem of gear discarding, and guidelines for monitoring schemes elsewhere