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Seabirds

Albatrosses and Petrels Albatrosses and Petrels

Ocean waters that are productive for sea life also support large numbers of foraging seabirds. New Zealand's offshore waters support tens of thousands of seabirds, including many albatross and petrel species. Interactions between New Zealand's EEZ trawl fisheries and seabirds occasionally results in the accidental injury or death of seabirds, usually caused by birds encountering the trawl lines or nets while competing for food around the vessel. Seabirds are prevalent in both number of species and birds around the NZ EEZ, especially in summer months when breeding occurs on the many offshore islands. During winter many species migrate to other parts of the world to enjoy better weather and feeding conditions. The juveniles of various species often live near other continents such as South Africa or South America until they are ready to breed, which may take several years.

The Deepwater Group is committed to reducing the risks of injury and harm to seabirds through mitigating such interactions. Unprecedented levels of direct (and indirect) well-resourced collaborative actions to reduce the adverse effects of seabird interactions have occurred over the last three years. This work commenced with a focus on the squid fishery where many interactions occurred and has now expanded to directly encompass all large trawlers operating in the New Zealand EEZ.

Seabird Behaviour

Research on seabird behaviour shows that different seabird species behave in different ways when interacting with fishing vessels at sea. Since 2005, the Deepwater Group has instigated vessel-specific management measures to mitigate seabird interactions with large trawlers.

These management measures are now audited by the Ministry of Fisheries and have proven successful in significantly reducing the numbers of interactions with seabirds. Different seabird behaviours and vessel specific harvesting practices have dictated the need for seabird mitigation devices and practices that are tailored to suit each vessel in the form of Vessel Management Plans (VMPs).

Interactions with Long Liners

Seabird interactions also occur at times with long line fishing, when seabirds either dive for baited hooks as the vessels are setting gear, or dive for fish caught on hooks as the gear is being hauled in. Operational procedures have now been introduced to minimise these interactions and include practices such as:
  • setting gear at night to reduce the visual attraction
  • using "tori lines" when setting and hauling from the vessel stern. Tori lines are lines that are trailed behind the boat with a series of drop-down streamers hanging above the baited lines. These streamers discourage the seabirds from flying near the fishing gear as it is deployed or retrieved
  • using weights on the lines to increase the sink rate of the lines and hooks moving them quickly out of the reach of foraging seabirds

Interactions with Trawlers

Batch discharging offal Batch discharging of offal to keep seabirds out of warp danger zone - note tori lines deployed

Foraging seabirds are attracted to the stern of trawlers as nets containing fish are being hauled on-board and as fish waste and offal are discarded during fish processing. The opportunistic and competitive nature of seabirds can lead to very large numbers of seabirds surrounding trawl vessels as they learn that there is a free and easy meal available.

Seabirds may be injured or killed by either encountering the warp wire of the trawlers or by getting caught in the net as they attempt to feed on fish inside the net during hauling. Mitigation devices and new operational procedures (VMPs) developed to reduce these interactions have seen large reductions in albatross deaths of around 70% over a 2 year period.

Warp Deflector deployed

Management initiatives have been developed both by the Deepwater Group in collaboration with the Ministry of Fisheries and DOC and by the Ministry through mandatory measures for trawlers.

Mandatory measures:

  • using "tori lines" when setting and hauling the trawl. These are similar in construction as those used in on the Long Line vessels and serve the same purpose in discouraging the seabirds from flying, sitting or diving near the trawl warps
  • using "bafflers" which are similar to Tori Lines but differ in that they are attached to the warp wire by metal rings. They consist of streamer material hanging down from the warp to the water to discourage seabirds from resting or waiting on the water in or around the area of the warps
Bird Baffler deployed Bird Baffler deployed
  • using shrouds as an alternative to bafflers which covers the area under the warps with a range of solid materials such as plastic sheets and the like to again discourage seabirds from resting or waiting on the water in or around the area of the warps.

DWG Vessel Specific VMP Measures:

  • offal discard management procedures including:
  • batch discharges of offal rather than continuous discharging. This reduces the overall time seabirds are attracted to the "danger zones"
  • withholding offal discharges while trawling to reduce the number of seabirds feeding while the warps are in the water
  • rendering (mealing) squid offal rather than discharging it. While this produces a lower quality fish meal product, it again reduces the attraction for seabirds hence reducing risk.