OSC report on Hector’s and Māui dolphins available online

Ocean Science Consulting NZ (Asia-Pacific) Limited (OSC-NZ) recently collaborated with colleagues at JASCO Applied Sciences (JASCO) and Cawthron Institute (New Zealand) to write a detailed literature review (Lucke et al., 2019) of potential non-fishing threats faced by Hector’s (Cephalorhynchus hectori hectori) and Māui dolphin (C. h. maui). The review was commissioned by Department of Conservation (DOC) and Fisheries New Zealand (FNZ) which are currently in the process of updating their Threat Management Plan (TMP). 

This literature review focussed on the ‘knowns and unknowns’ of potential impacts from Oil and Gas (O&G) production and mineral exploration on Hector’s and Māui dolphins in New Zealand waters. Overall, assessment of potential impacts on these animals was hampered by lack of information, specifically regarding effects of acoustic emissions. To fill these knowledge gaps, OSC’s review primarily consulted information from studies conducted overseas, applying knowledge from the harbour porpoise (Phocoena phocoena), a well-studied, similarly-sized, anatomically, physiologically, and ecologically-comparable species as a proxy for Hector’s and Māui dolphins. 

Harbour porpoises face many potential threats in the northern hemisphere, similar to those affecting Hector’s and Māui dolphins in New Zealand waters. Particularly sounds emitted during seismic surveys and offshore pile-driving have extremely loud source levels; however, auditory information has indicated this risk to be relatively low. Other major activities, such as drilling, dredging, and vessel traffic might only pose minor risks for auditory impairment, but can have ecological implications, such as exclusion from areas where activities are occurring, and habitat destruction. 

The optimal techniques to mitigate physical or behavioural effects of anthropogenic activities on Hector’s and Māui dolphins are avoidance of areas and implementation of additional buffer zones during biologically important activities, coupled with strict adherence to existing, or activity-specific monitoring and mitigation schemes when activities are permitted to occur. 

DOC and FNZ need your feedback on the proposed plan to protect Hector’s and Māui dolphins. If you would like to have a say in the conservation of these animals, you’ll need to act fast as the submission deadline for responses closes at 10:00am on Monday 19th August 2019 New Zealand time.

If you would like to learn more about these sub-species, also have a look at our news article on Maui’s dolphins (here).

References:

Download PDF
Lücke, K., Clement, D., Todd, V., Williamson, L., Johnston, O., Floerl, L., Cox, S., Todd, I., McPherson,
C.R. (2019) Potential Impacts of Petroleum and Mineral Exploration and Production on Hector’s and Māui Dolphins. Document 01725, Version 1.0. Technical report by JASCO Applied Sciences, Cawthron Institute, and Ocean Science Consulting Ltd. for the Department of Conservation, New Zealand.
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ON THE ‘ROUNDED’ EDGE OF EXTINCTION – Māui’s dolphin (Cephalorhynchus hectori maui)

Toitū te marae a Tāne-Mahuta, Toitū te marae a Tangaroa, Toitū te tangata
If the land is well and the sea is well, the people will thrive (Maori proverb)

On 7th May 2019, the Intergovernmental Science Policy Platform on Biodiversity and Ecosystem Services (IPBES) released the first global biodiversity assessment since 2005 (draft chapters and summary report). Comprising nearly 15,000 references, a team of 150 leading international experts of the natural and social sciences from 50 countries worked with IPBES for more than three years to inform better policies and actions. Release of the ‘Summary for policy makers’, launched at the United Nations Educational, Scientific and Cultural Organisation’s (UNESCO’s) world headquarters in Paris, lead to a global outcry of dismay from the media and conservationists to strive for a transformative change of our society. The summary discusses the main causes of biodiversity loss and outlines the future for their conservation over the next three decades.

According to the international report, over one million species worldwide are currently threatened with extinction, with declines accelerating. Among these are 4,000 endemic (only found in) New Zealand (NZ) species, including: the Maud Island Frog (Leiopelma pakeka), NZ fairy tern (Sternula nereis davisae), NZ pigeon (Hemiphaga novaeseelandiae) and the famous flightless kiwis (Apteryx sp.). Three of NZ’s endemic marine mammals have also been classified as threatened: NZ sea lion (Phocarctos hookeri) and NZ’s only endemic cetaceans, two recently recognised subspecies of Hector’s dolphin (Cephalorhynchus hectori), the South Island’s Hector’s dolphin (C. h. hectori) and the North Islands’ Māui’s dolphin (C. h. maui; Baker et al., 2002). Both subspecies are the world’s only known cetaceans with a well-rounded dorsal fin, and are hence easily identified.

Photographs of Māui’s dolphins (Cephalorhynchus hectori maui) displaying clearly visible rounded dorsal fin and characteristic colour patterns. Source: DoC (2019a).

Photographs of Māui’s dolphins (Cephalorhynchus hectori maui) displaying clearly visible rounded dorsal fin and characteristic colour patterns. Source: DoC (2019a).

Recognition of a new subspecies follows certain protocols; once a population has been isolated geographically and reproductively, to the extent that the subspecies has developed morphological or genetic distinctions from the original species, but still has the potential to effectively cross-reproduce (Mayr, 1970), it can be considered a subspecies. In the case of the Hector’s dolphin, four sub-populations have been identified genetically (Pichler, 2002), with no gene flow connection between the three South Island populations to the smallest population solely residing off the North Island, presumably isolated for 15–16,000 years, named Māui’s dolphin (Baker et al., 2002; Hamner et al., 2012). Although the two subspecies may look identical, sharing the same features of a rounded black dorsal fin and a lightly grey coloured body, black and white patterning around their heads and along their ventral body side, they are genetically and morphologically different. Māui’s dolphins have larger skulls and longer, wider rostrums (‘snout’ part of the skull) and can be differentiated through mitochondrial DNA and microsatellite genotype analysis (Hamner et al., 2012).

The world’s smallest known dolphin, Māui’s dolphin is a subspecies to one of four species in the genus Cephalorhynchus, all of which are small dolphin’s, endemic to coastal waters of the Southern Hemisphere (Dawson, 2018). The name Māui originates from the indigenous NZ language ‘Maori’, and its name for the North Island, namely ‘Te Ika a Māui’, translating to ‘the fish of Māui’. According to Māori mythology, demigod Māui was fishing with his magic fishhook off the South Island, when he caught a great fish that later became the North Island, where Māui’s dolphins have been found.

Primarily residing in waters less than 150 m depth, their diet consists of small schooling fish and squid, reflecting prey availability (reviewed in Miller et al., 2012). While many other dolphins use whistles to communicate via echolocation, Cephalorhynchus dolphins appear to rely solely on high frequency clicks (Dawson, 2018). Research suggests that this technique (also applicable to porpoises, e.g. harbour porpoises, Phocoena phocoena) might have evolved as an anti-predator mechanism against killer whale (Orcinus orca) predation, due to decreased chances of detachability (Morisaka and Connor, 2007). To enable the public to better understand their communication, the University of Otago, NZ, has transformed their sound clicks (with 125Hz) to a lower frequency, allowing humans to hear their voices.

Distribution of Māui’s dolphin, once a more widely observed species along the west and east coasts of the North Island (Slooten et al., 2005), has been restricted to a region of approximately 140–300 km in length along the west coast of the North Island (Oremus et al., 2012; Brough et al., 2019; de Jager et al., 2019).

Probability distribution of the occurrence of Māui’s dolphins along the west coast of New Zealand’s North Island according to a simulated distribution model (coloured areas) in correlation to trawling and gillnet prohibition zones (dashed areas). Source: de Jager et al. (2019).

Probability distribution of the occurrence of Māui’s dolphins along the west coast of New Zealand’s North Island according to a simulated distribution model (coloured areas) in correlation to trawling and gillnet prohibition zones (dashed areas). Source: de Jager et al. (2019).

There are a wide variety of potential threats to this species; however, the primary reason for their decline is believed to stem from fishing activities and increasing marine traffic as outlined in the ‘Hector’s and Māui’s dolphin Threat Management Plan’ (DoC, 2007).

Variety of potential anthropogenic threats to Māui’s dolphins. Source: OSC (2019).

Variety of potential anthropogenic threats to Māui’s dolphins. Source: OSC (2019).

To try and reverse this population decline, the NZ government established a marine mammal sanctuary along the west coast off the North Island (DoC, 2013), and implemented a range of restrictions to commercial net fishing activities (Stewart and Callagher, 2013), with increased enforcements after the death of a Māui dolphin in 2012 (Hamner et al., 2014). All these restrictions have not yet been sufficient to enhance the population recovery (de Jager et al., 2019). While anthropogenic factors still pose the biggest overall threat to marine mammals, a recent study identified an infectious disease, Toxoplasmosis, to be the cause of 25{2b968f05dd8408870fcd493523ca74153f475ecfd42eba24afe83388f01ad232} of mortality of Hector’s dolphins (Roe et al., 2013). More research needs to be conducted in order to fully understand the role of this disease in the marine environment and its infectious potential and linkage between humans and marine mammals (Van Bressem et al., 2009).

As a result to the decline of the Māui’s dolphin, the species has been classified as ‘critically endangered’ by the International Union for Conservation of Nature (IUCN, 2012) and as ‘Nationally critical’ by the Department of Conservation (DoC) in the New Zealand Threat Classification System (Baker et al., 2010; Baker et al., 2016b). Recent microsatellite genotype identification models, particularly useful for the low number of natural body markings, revealed that the population has likely declined during the study periods of 2001–2016, with an estimated remaining population size of around 55–63 individuals (Baker et al., 2013; Baker et al., 2016a). Unfortunately, in addition to their restricted geographic range and small population size, Hector’s dolphins in general have a slow reproduction rate and are relatively short-lived, with females reaching reproductive age nearly half way (7-9 years) through their maximum age up of around 20 years (Slooten, 1991), additionally endangering their survival (Davidson et al., 2012).

Overall, the species with the characteristically round shaped dorsal fin are an important part of NZ’s natural heritage, similar to the kiwi. Although Māui’s dolphins are extremely threatened, there is still hope for subspecies if further mortalities are prevented. To engage the public on their protection, the NZ government, DoC, has launched a community sighting program (‘Rounded fin? Send it in!’) and is working with a range of stakeholders and local scientists to find additional ways to protect the species.

Slogan of NZ’s sighting program campaign to report any sightings of Māui’s or Hector’s dolphin. Source: DoC (2019b).

Slogan of NZ’s sighting program campaign to report any sightings of Māui’s or Hector’s dolphin. Source: DoC (2019b).

REFERENCES:

Baker, A.N., Smith, A.N., and Pichler, F.B. (2002): Geographical variation in Hector’s dolphin: Recognition of new subspecies of Cephalorhynchus hectori. Journal of the Royal Society of New Zealand 32, 713-727.

Baker, C., Chilvers, B., Constantine, R., DuFresne, S., Mattlin, R., Van Helden, A., and Hitchmough, R. (2010): Conservation status of New Zealand marine mammals (suborders Cetacea and Pinnipedia), 2009. New Zealand Journal of Marine and Freshwater Research 44, 101-115.

Baker, C., Hamner, R., Hickman, G., Boren, L., Arlidge, W., and Constantine, R. (2016a): Estimating the abundance and effective population size of Māui’s dolphins using microsatellite genotypes in 2015–16, with retrospective matching to 2001–07. Department of Conservation, Auckland, 1-70.

Baker, C.S., Chilvers, B., Childerhouse, S., Constantine, R., Currey, R., Mattlin, R.H., Van Helden, A., Hitchmough, R., and Rolfe, J.R. (2016b): Conservation status of New Zealand marine mammals, 2013. Publishing Team, Department of Conservation.

Baker, C.S., Hamner, R.M., Cooke, J., Heimeier, D., Vant, M., Steel, D., and Constantine, R. (2013): Low abundance and probable decline of the critically endangered Maui’s dolphin estimated by genotype capture-recapture. Animal Conservation 16, 224-233.

Brough, T., Rayment, W., Slooten, E., and Dawson, S. (2019): Fine scale distribution for a population of New Zealand’s only endemic dolphin (Cephalorhynchus hectori) shows long‐term stability of coastal hotspots. Marine Mammal Science 35, 140-163.

Davidson, A.D., Boyer, A.G., Kim, H., Pompa-Mansilla, S., Hamilton, M.J., Costa, D.P., Ceballos, G., and Brown, J.H. (2012): Drivers and hotspots of extinction risk in marine mammals. Proceedings of the National Academy of Sciences of the United States of America 109, 3395-400.

Dawson, S.M. (2018): Cephalorhynchus Dolphins: C. heavisidii, C. eutropia, C. hectori, and C. commersonii: Encyclopedia of marine mammals. Elsevier, pp. 166-172.

de Jager, M., Hengeveld, G.M., Mooij, W.M., and Slooten, E. (2019): Modelling the spatial dynamics of Maui dolphins using individual-based models. Ecological Modelling 402, 59-65.

DoC (2007): Hector’s and Maui’s Dolphin Threat Management Plan: Draft for public consultation. Ministry of Fisheries and Department of Conservation.

DoC (2013): Marine Mammals Protection (West Coast North Island Sanctuary) Notice 2008. Reprint, Published under the authority of the New Zealand Government, Wellington, New Zealand.

DoC (2019a): Māui dolphin. Available at: https://www.doc.govt.nz/nature/native-animals/marine-mammals/dolphins/maui-dolphin/ [Accessed 07/06/19].

DoC (2019b): Report sightings of Māui dolphin. Available at: https://www.doc.govt.nz/nature/native-animals/marine-mammals/dolphins/maui-dolphin/report-sightings/ [Accessed 07/06/19].

Hamner, R.M., Pichler, F.B., Heimeier, D., Constantine, R., and Baker, C.S. (2012): Genetic differentiation and limited gene flow among fragmented populations of New Zealand endemic Hector’s and Maui’s dolphins. Conservation Genetics 13, 987-1002.

Hamner, R.M., Wade, P., Oremus, M., Stanley, M., Brown, P., Constantine, R., and Baker, C.S. (2014): Critically low abundance and limits to human-related mortality for the Maui’s dolphin. Endangered Species Research 26, 87-92.

IUCN (2012): Actions to avert extinctions of rare dolphins: Maui’s dolphins, Hector’s dolphins, Vaquita and South Asian river dolphins.

Mayr, E. (1970): Populations, species, and evolution: an abridgment of animal species and evolution. Harvard University Press.

Miller, E., Lalas, C., Dawson, S., Ratz, H., and Slooten, E. (2012): Hector’s dolphin diet: the species, sizes and relative importance of prey eaten by Cephalorhynchus hectori, investigated using stomach content analysis. Marine Mammal Science.

Morisaka, T., and Connor, R.C. (2007): Predation by killer whales (Orcinus orca) and the evolution of whistle loss and narrow-band high frequency clicks in odontocetes. Journal of Evolutionary Biology 20, 1439–1458.

Oremus, M., Hamner, R.M., Stanley, M., Brown, P., Baker, C.S., and Constantine, R. (2012): Distribution, group characteristics and movements of the Critically Endangered Maui’s dolphin Cephalorhynchus hectori maui. Endangered Species Research 19, 1-10.

Pichler, F.B. (2002): Genetic assessment of population boundaries and gene exchange in Hector’s dolphin. Department of Conservation Wellington (New Zealand).

Roe, W.D., Howe, L., Baker, E.J., Burrows, L., and Hunter, S.A. (2013): An atypical genotype of Toxoplasma gondii as a cause of mortality in Hector’s dolphins (Cephalorhynchus hectori). Veterinary Parasitology 192, 67-74.

Slooten, E. (1991): Age, growth, and reproduction in Hector’s dolphins. Canadian Journal of Zoology 69, 1689-1700.

Slooten, E., Dawson, S., Rayment, W., and Childerhouse, S. (2005): Distribution of Maui’s dolphin, Cephalorhynchus hectori maui. New Zealand Fisheries Assessment Report 28, 21.

Stewart, J., and Callagher, P. (2013): Industry response to the 2003 set net restrictions for protection of Maui′s dolphin. Marine Policy 42, 210-222.

Van Bressem, M.F., Raga, J.A., Di Guardo, G., Jepson, P.D., Duignan, P.J., Siebert, U., Barrett, T., Santos, M., Moreno, I.B., Siciliano, S., Aguilar, A., and Van Waerebeek, K. (2009): Emerging infectious diseases in cetaceans worldwide and the possible role of environmental stressors. Diseases of Aquatic Organisms 86, 143-157.

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OSC NZ to participate in 2016 A Community on Ecosystem Services conference in Florida

OSC NZ will be at the 2016 A Community on Ecosystem Services (ACES) conference, which is being held in Jacksonville, Florida, USA from 5-9 December. The ACES conference focuses on bringing together decision-making and the science around ecosystem services and sustainability.

Dr Victoria Todd, one of our Managing Directors, will participate in the Thursday afternoon discussion session entitled ‘Do offshore oil and gas platforms and infrastructure provide valuable ecosystem services?’. This session will explore the ecological value of offshore oil & gas (O&G) subsea structures and applying Net Environmental Benefit Analyses (NEBA) to assess decommissioning options of those structures. NEBAs make use of the latest scientific data and case studies, such as the recent research which indicates that the reefs associated with O&G subsea infrastructure can support a variety of marine mammal populations.

See you there!

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Victoria & Ian Todd attend Aquatic Noise 2016 conference in Dublin

Two of OSC NZ’s directors, Dr Victoria Todd and Ian Todd, recently attended the fourth international The Effects of Noise on Aquatic Life conference (AN2016), held in Dublin, Ireland, 10–15 July 2016.

The conference covered a broad range of topics related to the central theme of impacts from man-made noise, including research on marine mammal activities, the use of different technologies to study marine mammal activities, noise levels in the ocean and around certain activities (e.g. shipping, pile-driving, wire-cutting) and impacts of noise on fish (including some fascinating research from NZ on the effects of boat noise on temperate reef fish). The conference combined regulatory, industry and academic perspectives, leading to interesting exchanges of ideas and discussions.

Whilst OSC NZ is, of course, interested in the direct impacts of noise on marine mammals, the responses of their prey (e.g. fish) to noise are likely to also impact marine mammals, so many of the talks had implications that link to our research interests. Wide-ranging conferences such as AN2016 provide valuable new perspectives on noise-related issues, and allow scientists (from academia and industry) to keep up-to-date with research in associated fields.

Ian & Max Ruffert catching up at the conference

Ian & Max Ruffert

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MMO & PAM Handbook hailed as industry ‘bible’

The Marine Mammal Observer & Passive Acoustic Monitoring Handbook, written by Dr Victoria Todd, Ian Todd, Jane (Gardiner) Warley and Erica (Morrin) Chapman and drawing on their extensive collective experience working for OSC, has been hailed as a ‘bible’ for the industry in a review published in Marine Mammal Science.

The Marine Mammal Observer & Passive Acoustic Monitoring Handbook remains the only book of its kind and is both an invaluable resource for those interested in joining the industry and a comprehensive reference for experienced readers. The book provides an overview of marine mammal species and noise, mitigation legislation around the world, training requirements and life offshore. Good practice for Marine Mammal Observers (MMOs) is discussed also, and a wealth of information about Passive Acoustic Monitoring (PAM) and using PAMGuard (the industry-standard software used for PAM) is provided.

Available in hardback, paperback and eBook (very practical when considering offshore luggage allowances) from Pelagic Publishing, NHBS and Amazon.

Marine-Mammal-Observer-and-Passive-Acoustic-Monitoring-Handbook-montage

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Watch Ian & Erica’s presentation at the PEPANZ 2016 conference

Ian Todd and Erica Chapman, both directors of OSC NZ, presented at the recent PEPANZ 2016 conference in Auckland, NZ. Their talk was entitled “Enhancing oil & gas exploration activities with Māori culture and creating career pathways – iwi Marine Mammal Observer (MMO) and Passive Acoustic Monitoring (PAM) training course”.

Watch their presentation here (Ian & Erica’s presentation slot starts at 21:30), where they discuss their experiences running the course (their first full marae experience!) and some of the feedback from the 16 iwi candidates, as well as how both OSC NZ and some of the candidates think that the knowledge and skills learnt on this course can benefit both their iwi and the oil & gas industry in NZ.

COSC_Ian&EricaPresentation_NZ

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Watch Victoria’s rigs-to-reef talk at the PEPANZ 2016 conference

Victoria Todd, one of our Managing Directors, presented about OSC’s North Sea rigs-to-reef research at the recent PEPANZ 2016 conference, held in Auckland, NZ. She discusses why our findings are important for offshore installations coming to the end of their lifespans as well as why replicating this research in NZ could be important for the Critically-Endangered Maui’s dolphin.

 

Victoria Todd presenting at the 2016 PEPANZ conference

Victoria Todd presenting at the 2016 PEPANZ conference

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New publication: Meals on wheels? A decade of megafaunal visual and acoustic observations from offshore Oil & Gas rigs and platforms in the North and Irish Seas

OSC’s new paper ‘Meals on wheels? A decade of megafaunal visual and acoustic observations from offshore Oil & Gas rigs and platforms in the North and Irish Seas’ was published by PLoS One this month, and is available to download here.

The paper presents a decade of visual and acoustic detections of marine megafauna around offshore Oil & Gas (O&G) installations in the North and Irish Sea.  Marine megafauna activity was monitored visually and acoustically by Joint Nature Conservation Committee (JNCC) qualified and experienced Marine Mammal Observers (MMO) and Passive Acoustic Monitoring (PAM) Operators respectively, with real-time towed PAM in combination with industry standard software, PAMGuard. Monitoring was performed during routine O&G industrial operations for underwater noise mitigation purposes, and to ensure adherence to regulatory guidelines.

This study compliments OSC’s previous research on porpoises around O&G installations, and provides further evidence that marine megafauna are present around mobile and stationary offshore O&G installations during routine operational activities.

Minke whale (Balaenoptera acutorostrata) around the legs of an oil and gas installation

Minke whale (Balaenoptera acutorostrata) around the legs of an oil and gas installation

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OSC attend New Zealand Petroleum Conference 2016

Last week OSC-NZ Directors Ian and Victoria Todd and Erica Chapman attended the New Zealand Petroleum Conference, held in Auckland between 20-22nd March. More information about the conference is available here, www.petroleumconference.nz.

All three presented at the conference, with a photograph below of Ian and Erica presenting their talk entitled ‘’Enhancing oil & gas exploration activities with Māori culture and creating career pathways – iwi Marine Mammal Observer (MMO) and Passive Acoustic Monitoring (PAM) training course’.

More photos of the conference and New Zealand are up on our Facebook page, www.facebook/OSCLtd

COSC_Ian&EricaPresentation_NZ

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Melanie Orr appointed Director of OSC-NZ

OSC-NZ is pleased to announce that Melanie Orr  has been appointed as a Director of OSC-NZ, the Asia-Pacific branch of Ocean Science Consulting (OSC; www.osc.co.uk). She joins Ian Todd, Victoria Todd and Erica (Morrin) Chapman on the board. Along with completing day-to-day business activities, Melanie is the main New Zealand-based contact for OSC-NZ.

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