Dolphin protection plan – Expert Reaction

Published: Mon 17 Jun 2019 12:27 PM
The Government has proposed plans to expand protection for Māui and Hector's dolphins.
A discussion document, released today, includes proposals to extend the boundaries of two marine mammal sanctuaries and identifies threats to the dolphins including toxoplasmosis spread by cats.
The SMC asked experts to comment on the plan, feel free to use these comments in your reporting.
Associate Professor Karen Stockin, Massey University, comments:
"It is great to see the New Zealand Government release this much needed Threat Management Plan for the Hector’s and Māui dolphins. It has been a huge body of work for which many people have contributed.
"Despite the recent downgrading in threat status of the Hector's dolphins to nationally vulnerable, it is apparent there is still much to do to ensure successful conservation efforts for this and the nationally critical subspecies, Māui dolphins.
"In my opinion, the acknowledgement and discussion of broader threats beyond just fisheries bycatch is welcome as a much-needed step forward for successful management of this genus.
"Disease has historically been overlooked in the wider assessment of impacts likely affecting all New Zealand marine mammals. Undoubtedly, the recent discovery of toxoplasmosis is an important finding which I hope the government will not only explore further, but broader in the context of disease screening.
"One thing pleasing to see stated in the Threat Management Plan is the need for multi-disciplinary agreement on toxoplasmosis mitigation. As part of this, I am hopeful the government will conduct further assessment of toxoplasmosis in a wider context to what appears in the Threat Management Plan presently. For example, in many mammalian species including marine mammals and humans, we know that toxoplasmosis is often a secondary disease, present within organisms (sometimes without consequence) until such a time when a primary disease and/or elevated or cumulative contaminant burden suppresses immunity.
"As such, as part of this Threat Management Plan, I would encourage the government to support a broader disease surveillance programme (above and beyond just toxoplasmosis) and that factors likely to suppress immunity, such as persistent contaminants, are fully evaluated and within a cumulative framework. For example, only a handful of legacy contaminants have been examined in isolation for New Zealand marine mammals. However, in the context of current disease concerns, we need to look towards assessing cumulative impacts and notably, including emerging contaminants in our evaluations."
Conflict of interest statement: Speaking in my capacity as a New Zealand researcher of marine mammals - NOT in any International Whaling Commission capacity.
Professor Steve Dawson and Professor Liz Slooten, University of Otago, comment:
"Plans for protecting Hector’s and Māui dolphins, released this morning, are based on flawed science and the protection plans are piecemeal.
"The plan states that disease is a much bigger problem than bycatch, despite no robust evidence this is so, and against advice from an invited team of experts. With current data, there is no scientifically valid way to estimate the number of dolphin deaths from disease.
"The Expert Panel report includes a long list of other problems with the MPI model and its conclusions. Essentially, the MPI approach failed this peer review.
"MPI have almost certainly under-estimated how many dolphins are dying in fishing nets, due to very low observer coverage (2-3%) and problems with estimating the overlap between dolphins and fishing. The MPI approach is complex, and a one-off. It has not been published in a peer-reviewed journal and is very sensitive to the many assumptions made.
"Recently reported dolphin deaths, which include three and five dolphins caught in the same net, are inconsistent with MPI’s estimates.
"The simple solution is to use only dolphin-safe fishing methods (no gillnets or trawling), in all waters less than 100 metres deep throughout the range of Hector’s and Māui dolphins."
No conflicts of interest.
Associate Professor Rochelle Constantine, University of Auckland, comments:
"The consultation document for the Threat Management Plan clearly lays out the known threats to our endemic Hector's and Māui dolphins and provides options to mitigate the risk of dolphin deaths alongside the economic impacts where changes to fisheries are suggested.
"This is the most comprehensive assessment of the status of Hector's and Māui dolphins with toxoplasmosis, transmitted by cat faeces, and fisheries entanglement the main known causes of death. Setnets are the fishing gear that poses the greatest risk to dolphins, this is without a full assessment of the recreational setnet deaths so the number is likely higher. It is important to note that this is not a 'one size fits all' plan. The risks of death are not the same throughout the dolphins' range therefore, the options account for different management actions in different regions.
"The threat from toxoplasmosis, which is spread from cat faeces, is one of our greatest challenges as there are gaps in knowledge about this disease, but cat owners play an important role in minimising spread of toxoplasmosis. The initiatives by councils, pest controllers and Predator Free New Zealand to control feral cats are very important to manage those threats.
"It is encouraging to see sub-lethal threats considered including mining, tourism, and seismic surveys as these non-direct impacts are likely to be amplified for populations that are isolated, very small and/or under stress. The effects on ecosystem function from habitat disturbance, prey availability and climate change impacts are increasingly of concern in our oceans."
Conflict of interest statement: Principal investigator on Maui and Hector's dolphin research; Member of the scientific advisory group for the Hector's and Maui Dolphin Threat Management Plan; Member of the New Zealand Threat Classification System for Marine Mammals.
Science Media Centre
Our aim is to promote accurate, evidence-based reporting on science and technology by helping the media work more closely with the scientific community.
The Science Media Centre is New Zealand's only trusted, independent source of information for the media on all issues related to science. Thousands of news stories providing context from and quoting New Zealand researchers have been published as a direct result of our work.
Contact Science Media Centre
Postal Address:
PO Box 598, Wellington 6140

Next in Business, Science, and Tech

Auckland port move: Cabinet ministers deliberate on decision
Dead rats washed up on beaches sent for toxicology testing
Resource Strategy plots path ahead for sector
By: Ministry of Business Innovation and Employment
Methane satellite mission control in New Zealand
By: New Zealand Government
Late spring surge as we head into summer
By: QV Valuations
New Zealanders feel financially better off
By: Statistics New Zealand
Moving port will cost Government, consumers and environment
By: National Road Carriers
Caution urged over rat carcasses on beach
By: Department of Conservation
MBIE plans for budget changes due to ‘no new mines’ policy
By: NZ Energy and Environment Business Week
Government’s resources strategy all spin and no substance
By: New Zealand National Party
Resource strategy could hinder delivery of energy to NZers
By: NZ Petroleum Exploration and Production Assn
Minerals Sector Contributes Significantly to Wellbeing
By: Straterra
"Shoddy" NZ oil strategy released as scientists raise alarm
By: Greenpeace
New Government mining strategy lacks urgency, clout
By: Forest And Bird
New Zealand joins MethaneSAT climate mission in space
By: Ministry of Business Innovation and Employment
View as: DESKTOP | MOBILEWe're in BETA! Send Feedback © Scoop Media