During winter, an elemental force of nature drives the seasonal migration of whales along New Zealand’s coastlines. Kiwis are in awe of these magnificent creatures and a very strong and extremely vocal environment and conservation ethic intends absolute protection for them. Daryl Sykes updates the initiatives being made by the rock lobster industry to avoid and mitigate whale interactions with fishing gear.
Whaling was New Zealand’s first European style industry, originating in 1791. From the mid 1820’s, shore whaling stations were established, with 80-113 established in a decade. The whaling industry was largely unregulated in the early years, causing an extensive decline in whale populations around New Zealand and the Southern Ocean.
The original New Zealand and Sub-Antarctic population of southern right whales was estimated to be around 28,000 individuals; this was reduced to the point of almost extinction (40 breeding females) as they were a target or ‘right’ species for whalers. Today, even after 80 years of protection, the population is only 12% of what it was.
New Zealand waters are occupied by nine species of baleen whales, three species of sperm whales, 13 species of beaked whales, one species of porpoise, and at least 18 species of dolphins. New Zealand straddles the migration routes of many of the large and medium sized whales, travelling through the southwest Pacific between the tropics and Antarctic—a fact exploited by early whalers.
Entanglements a global problem
Interactions between whales and commercial fisheries have occurred worldwide for centuries but are increasing in frequency—a trend likely to continue as demand for high quality, high value seafood continues, whilst whale populations increase annually.
Seventeen countries have confirmed reports of whale entanglements. Historically, entanglements with commercial rock lobster gear in New Zealand have been low but, with the whale population increasing, the risk is heightened. This could impact the fishing industry, particularly if entanglements result in whale mortalities.
In the 33 years between 1984 and 2017, 44 large whale entanglements in New Zealand waters were reported, of which 39 were attributable to pot/trap and set net fisheries. Twenty-five (64%) involved humpback whales, eight (21%) orca, three (8%) southern right whales, one minke whale, one blue whale and one unknown baleen whale were documented as entangled. From 1991-2017, 1.4 whales per year were reported as entangled in pot/trap and set net fisheries. 62% of large whale entanglements involved rock lobster and ‘likely’ rock lobster gear, 21% of entanglements involved set net gear, and 18% of entanglements involved either rope from an unknown gear type, or the gear involved in the entanglement was unknown.
WhaleSafe a Kiwi initiative
The NZ Rock Lobster Industry Council has been proactive in raising industry awareness to the risks of whale entanglements in fishing gear and in providing practical advice and guidance to facilitate the avoidance and mitigation of those risks.
Building on a local initiative by the CRA 5 Rock Lobster Industry Association (CRAMAC 5) the NZ RLIC implemented a WhaleSafe programme in 2012 to help pot and trap fishermen avoid and/or mitigate the risk of entanglements, updating the programme annually to ensure that the best available information, guidance, and technology is being used. Initiatives to date include the compilation and distribution of the NZ RLIC WhaleSafe Manual, which has been recently updated and republished in a new edition.
The third edition comprises a booklet containing detailed information about whale movements and behaviour, a sequence of photos and illustrations to enable identification of the different cetacean species; and advice on how to set gear to avoid entanglements. The material in the booklet was commissioned from Dr Martin Cawthorn who is regarded internationally as an expert on cetacean biology and behaviour.
Dr Cawthorn has been a member of the Scientific Committee of the International Whaling Commission since 1977, a Charter Member of the Society for Marine Mammalogy since 1984, a member of IUCN Species Survival Commission’s Specialist Groups on Whales and Seals, and recipient of the New Zealand Antarctic Society Conservation Award (1984) for work on Hooker’s sea lion and Antarctic minke whales. He was an instigator and co-author of the Marine Mammal Protection Act 1978. He was principal author of the Australian Fisheries Management Authority Code of Fishing Practice for the Southeast Trawl Fishery.
His experience has included work in New Zealand, South West Pacific and Polynesia, Eastern tropical pacific, Central and South America, South Atlantic, Southern Indian Ocean, Southern Ocean/ Antarctic, Western North Atlantic, Canadian Arctic, and the Norwegian Sea.
Supplementary to the WhaleSafe Manual has been the development and refinement of OceanSnap, an Android smartphone application that enables detailed observations of marine life to be reliably uploaded to an online database administered by the NZ RLIC. Although initially not without technical challenges, the latest Android version of OceanSnap (<oceansnap. co.nz>) has been field tested and demonstrated to be reliable.
DOC dis-entanglement team
The Department of Conservation (DOC) has trained personnel to respond to entangled whales. To assist their efforts, the NZ Rock Lobster Industry Council has purchased and donated three GPS tracker buoys.
When an entangled whale is detected, DOC is notified and the Entanglement Response Team will first determine if they are able to attach a buoy to the whale. This will be impacted by weather, daylight hours, crew/vessels and if the vessel reporting the entanglement is able to stay with the whale until a crew arrives. Without real-time tracking, locating or even maintaining contact with an entangled whale can be very challenging, as they are often not re-sighted after they are initially reported.
Coastal migrating whales face the greatest risk of entanglement when encountering vertical pot lines in their path, which have to be negotiated without contact. Gear modifications therefore have two basic aims; to reduce the number of vertical lines from pots on the seafloor to buoys at the surface and avoid entanglement of passing whales, while allowing fishing to successfully continue.
Responsible lobster fishing
These mitigation methods are considered minimal requirements for responsible lobster fishing:
• Where possible avoid setting pots in tight clusters.
• Avoid excessive slack in pot ropes. Ropes should be adjusted to a length appropriate to the depth and strength of tide being worked, especially inshore. Excess slack in pot ropes can be coiled and tied close to floats.
• Slack line should be limited to enough rope to allow for recovery and to commence hauling safely (dog bone/shanking).
• Do not leave pots in water for prolonged periods if not fishing. Pots should be retained onboard or returned to shore if not fishing for long periods.
• Regularly check pots as per standard fishing practice. The DOC Disentanglement Teams have a greater chance of success if an entangled whale is quickly discovered.
Approaching an entangled whale is dangerous and requires specific training and approvals. Report any entanglements ASAP. Rapid reporting ensures that DOC Entanglement Response Teams have the best chance of disentangling a whale. Fishermen should monitor entanglement situations, with due regard for the safety of the vessel and the whale, until assistance teams arrive.
The NZ Rock Lobster Industry Council WhaleSafe Manual is available to all fisherfolk as a PDF file.
Follow this link on the NZ RLIC website – <nzrocklobster.co.nz/whalesafe>for your copy.
