A series of full page advertisements in the Dominion Post by Seafood NZ is suggestive of an industry throwing its weight and money behind a ‘lip service’ campaign to reassure the public of a sustainable industry. Science Advisor for Our Seas Our Future, Veronica Rotman, provides some feedback to these Seafood NZ advertisements...

Claims that “most (dolphins) feed around river mouths in the protected area", and the existing sanctuary is the "heart of the Maui habitat" are vague and based on data deficient assumptions. Maui dolphin habitat zone is largely inaccessible, along a rough coastline where boat surveys are near impossible for most of the year. Research is limited to summer months, with year-round distribution not well understood.

It is documented that Maui aggregate inshore during these months, however acoustic surveys suggest that they travel offshore during the winter months. This is likely outside the current protection area and both better protection measures and improved understanding of distribution are required to improve their situation. In order to gain an accurate understanding of where they live, potential habitat should be surveyed year round to reveal any temporal changes in distribution. Modelling of Maui prey should also be prioritised as the dolphin range may be changing with food sources and environmental conditions.

We challenge Seafood NZ to support research efforts to improve understanding of distribution including the use of drones, artificial intelligence, thermal imaging and acoustic monitoring. This information must be continually updated to develop informed spatial management decisions and implement effective policy.

The New Zealand Marine Mammals Act (1978) clearly states that bycatch mortality must be managed to ensure that threatened species should achieve non-threatened status as soon as practicable, not exceeding a period of 20 years. This is not possible with existing protection measures (Manning & Grantz, 2017).

Although a small portion of their range is protected, there is still considerable overlap between Maui dolphin habitat and commercial set net and trawl fisheries. Considering their conservation status as ‘Nationally critical’ and depleted population of ~63 individuals, any preventable bycatch should be considered unsustainable.

Recommendations provided by the International Whaling Commission (IWC) encouraged full protection from set net and trawl commercial fishing for both Maui and Hector's dolphins in the entirety of their range out to the 100 metre depth contour. Slooten 2014 suggested that creating small specific areas of protection does not solve the problem but merely shifts it to another area that is still an integral part of the species habitat. Large-scale issues requires a large-scale solution, and that providing protection out to the 100 metre depth contour throughout the species range would provide the best chance of population recovery (Slooten et al. 2013).

Until definitive information on dolphin spatial distribution has been acquired, OSOF urges extended protection measures from human-caused threats such as set net and trawls in the species range. We recognise that bycatch is the most immediate and manageable threat to these dolphins, however acknowledge the need for urgent research into non-fisheries related threats to give these dolphins the best chance of survival.

One advertisement states that the "Last confirmed death of a Maui dolphin by commercial fishing happened 17 years ago". Bycatch data sourced from “Dragonfly Data Science” indicated zero observed bycatch associated with set net or trawl commercial fisheries between 2003 and 2017. This is likely due to the extremely low observer coverage on boats. Set net commercial fisheries on the West coast of the North Island had an average observer coverage of <1%, while trawls were between 4%-55.5% during this time period (Abraham & Thompson, 2011; Dragonfly, 2018). It is proposed that set nets attribute 84% of the fisheries risk to Maui dolphins, however trawls had far greater coverage of observers (DOC, 2019).

The Department Of Conservation’s Maui dolphin incident database conversely displays the death of a Maui dolphin in 2012 with cause of death on the 02/01/2012, clearly stating “known bycatch in commercial setnet” (DOC). This is well within the previous 17 year time period and was reported by a commercial fisherman. However, because the dolphin was not brought ashore, a necroscopy was not performed, and on their Facebook page Seafood NZ claim that the dolphin ‘was not identified as a Maui’.

The incident database states that it relies on reports from fishing vessels, as well as public sightings of dead dolphins, and is bias to areas with high visitor numbers. In many cases, dolphin carcasses in this database have been found decomposed beyond the possibility of a necroscopy, and cause of death has not been determined.

The 2012 Maui Dolphin Threat Management Plan indicates that bycatch is likely under-reported. Ministry for Primary Industries (2017) suggest that the incidental capture information available on the DOC database is not representative of the scale or magnitude of fisheries capture. This is likely due to under-reporting, carcasses not washing ashore, or lack of evidence of interaction with fishing gear. International Whaling Commission representative, Elisabeth Slooten, suggested that not all dolphins caught in set-nets show symptoms of capture such as cuts on the snout, flipper or tail and fluid or foam in lungs or airways. Trawl deaths are even more difficult to distinguish as there are often no definitive diagnostic signs and diffuse bruising is the primary means of diagnosis. The recent 2019 Threat Management Plan Risk Assessment estimates that commercial fishing currently accounts for one Maui dolphin death every 9 years. Although fishermen are compelled by law to report any entanglements, there is no existing incentive to do so (MFish & DOC, 2007; Slooten, 2007).

Trawl commercial fisheries are known to cause fatalities in Hector's dolphins, however there have been no records of Maui dolphins caught as bycatch (MFish & DOC, 2007). Other cetacean species such as Common dolphins have been reported as bycatch in trawls operating off the west coast of the North Island, indicating the ongoing threat for bycatch of Maui dolphins is significant (Manning & Grantz, 2017). In order to evaluate the full extent of bycatch risk and mortality rate of Maui dolphins, observer coverage must be greatly improved.

If Seafood NZ cannot "countenance the obliteration of small fishing companies", then efforts should be made to support their transition to sustainable dolphin-safe fishing methods in the region, such as hook and line techniques and fish-traps. A recent report by Fisheries New Zealand estimated a financial loss of between $20.9 million and $143.5 million over five years depending on area of fishery closed. However, Market Economics’ associate director Rodney Yeoman suggested figures to be 10 times overestimated, urging the figures to be reviewed (Newsroom).

OSOF Founder, Noel Jhinku says “For Maui and Hector’s, cameras on boats, implementing a much greater observer coverage, industry investment in transitioning to dolphin-friendly fishing methods, more basic research to better understand populations, and incorporating the use of cutting-edge monitoring technology is needed to prevent extinction.”

References:

Abraham, E. R., & Thompson, F. N. (2011b). Summary of the capture of seabirds, marine mammals, and turtles in New Zealand commercial fisheries, 1998–99 to 2008–09. New Zealand Aquatic Environment and Biodiversity Report No. 80. 170 pages. Download from Ministry for Primary Industries.

https://www.osof.org

https://www.facebook.com/SustainableSeafoodNow/

DOC & MFish (2007) Department of Conservation, and the Ministry of Agriculture & Fisheries. Hector’s dolphin threat management discussion document, April 2007. Available at https://www.fish.govt.nz/en-nz/Environmental

DOC (2019) Consultation on proposals for an updated Threat Management Plan, June 2019. Available at http://www.fisheries.govt.nz/dolphintmp

DOC. 1 August 2011 - 31 July 2012. Retrieved from https://www.doc.govt.nz/our-work/hectors-and-maui-dolphin-incident-database/1-august-2011-31-july-2012/?fbclid=IwAR1bDs_9-OTqwEOI_2mb6c6CpTX-9dAU_ISw76lh9R4f6b1GfoffK1GytSQ

Dragonfly Data Science: Data. Retrieved from https://www.dragonfly.co.nz/data/

Manning, L., & Grantz, K. (2017). Endangered Species Act status review report for Hector's dolphin (Cephalorhynchus hectori). Retrieved from https://repository.library.noaa.gov/view/noaa/1629

Ministry for Primary Industries (2017). Aquatic Environment and Biodiversity Annual Review 2017. Compiled by the Fisheries Science Team, Ministry for Primary Industries, Wellington, New Zealand. 724 p.

Newsroom (2019, July 9). Cost of saving dolphins 'overstated' by 10 times. Retrieved from https://www.newsroom.co.nz/2019/07/09/672104/dolphin-plans-misleading-terms-and-overstated-costs

Slooten, E. (2007). Conservation management in the face of uncertainty: effectiveness of four options for managing Hector’s dolphin bycatch. Endangered Species Research, 3, 169-179. doi: 10.3354/esr003169

Slooten, E. (2014). Effectiveness for partial protection for Maui’s dolphin.

International Whaling Commission.

Slooten, E. (2013) Effectiveness of area-based management in reducing bycatch of the New Zealand dolphin. Endangered Species Research, 20(2), 121-130. doi: 10.3354/esr00483

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