Dolphin researchers say NZ’s proposed protection plan is flawed and misleading



Hector’s dolphins (Cephalorhynchus hectori) are found only in New Zealand.
Flickr/Scott Thompson, CC BY-ND

Elisabeth Slooten, University of Otago and Steve Dawson, University of Otago

The New Zealand government recently proposed a plan to manage what it considers to be threats to Hector’s dolphins, an endemic species found only in coastal waters. This includes the North Island subspecies Māui dolphin.

Māui dolphins are critically endangered and Hector’s dolphins are endangered. With only an estimated 57 Māui dolphins left, they are literally teetering on the edge of extinction. The population of Hector’s dolphins has declined from 30,000-50,000 to 10,000-15,000 over the past four decades.

The Ministry for Primary Industries (MPI) and the Department of Conservation (DOC) released a discussion document which includes a complex range of options aimed at improving protection.

But the proposals reveal two important issues – flawed science and management.




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Flawed science

Several problems combine to overestimate the importance of disease and underestimate the importance of bycatch in fishing nets. For many years, MPI and the fishing industry have argued that diseases like toxoplasmosis and brucellosis are the main cause of decline in dolphin populations. This is not shared by New Zealand and international experts, who have been highly sceptical of the evidence. Either way, it is not an argument to ignore dolphin deaths in fishing nets.

Three international experts from the US, UK and Canada examined MPI’s work. They concluded that it is not possible to estimate the number of dolphin deaths from disease, much less claim that this impact is more serious than bycatch. On the other hand, it is easy to obtain an accurate estimate of the number of dolphins dying in fishing nets, as long as enough observers are allocated. MPI has failed to do so. Coverage has been so low that MPI’s estimate of catch rates in trawl fisheries is based on one observed capture.

It would be possible to estimate dolphin deaths in trawl nets if enough observers were allocated.
Supplied, CC BY-ND

The MPI model used in the public discussion document (and described in more detail in supporting materials) is complex, and a one-off. It is based on a “habitat model” of dolphin distribution, but fits actual dolphin sightings poorly.

Another problematic aspect of the method is that there is no clear time frame for the “recovery” of dolphin populations to the specified 90% of the unimpacted population size for Hector’s dolphins and 95% for Maui dolphins. This is one of the first things any decision maker would want to know. Would Māui dolphins be held at the current critically endangered population level for another 50 years? If so, this dramatically increases their chance of extinction.

Flawed management options

The second set of problems concerns the management options themselves. These are a complex mix of regulations that differ from one area to another, for gillnets and trawling. They frankly don’t make sense. The International Whaling Commission (IWC) and International Union for Conservation of Nature (IUCN) have recommended banning gillnet and trawl fisheries throughout Māui and Hector’s habitats. MPI’s best option for Māui dolphins comes close to this in the middle of the dolphins’ range, but doesn’t go as far offshore in the southern part of their range.

The South Island options for Hector’s dolphin are much worse. MPI’s approach has been to try to reduce the total number of dolphins killed to just below the level they believe is sustainable. MPI has invented its own method for calculating a sustainable number of dolphin deaths, which is much higher than the well-tested method used in the United States. The next step has been to find areas where the greatest number of deaths can be avoided at the least cost to the fishing industry.

Several Hector’s dolphin populations in the South Island are small, but they act as a bridge between larger populations.
Supplied, CC BY-ND

This sounds reasonable, but fixing the problem only in the places where the largest number of dolphins is being killed will have several negative consequences. Experience shows that fishing effort shifts beyond protected areas, merely moving the problem.

For example, MPI’s proposals leave a large gap on the south and east side of Banks Peninsula, in prime dolphin habitat. If the nearby areas are protected, this gap will be fished, and dolphin bycatch will continue unabated. What’s needed is protection of the areas where dolphins live.

MPI’s focus on reducing the total number of dolphin deaths also ignores the fact that it really matters where those deaths occur. Several Hector’s dolphin populations in the South Island are as small, or smaller, than the Māui dolphin population.

Entanglement deaths have much worse consequences in such small populations, which form a bridge between larger populations. Yet they get no attention in the current options. MPI’s proposals would lead to the depletion of small populations, with increased fragmentation and extinction of local populations.

Only one option

If we want to ensure the long-term survival of these dolphins, there is only one realistic solution: to remove fishing methods that kill dolphins from dolphin habitat. The simple solution is to use only dolphin-safe fishing methods in all waters less than 100 metres deep. This means no gillnets or trawling in harbours and other coastal waters up to the 100 metre depth contour.

There is no need to ban recreational or commercial fishing, but we must make the transition to selective, sustainable fishing methods. These include fish traps, longlines and other hook and line methods. Selective, sustainable fishing methods also use less fuel than trawling and avoid impacts of trawling and gillnets on the broader marine environment.

We also need more observers and more cameras on fishing boats. MPI’s estimate of how many dolphins are dying in fishing nets is almost certainly an under-estimate. It depends heavily on assumptions that are not supported by data.

With observers on only about 2-3% of the inshore fishing boats, the chances of missing bycatch altogether is very high. Low observer coverage also means boats can fish differently on the days when they have an observer aboard (for example, avoiding areas where they have caught dolphins).

Selective fishing methods would protect dolphins and the broader marine environment.
Supplied, CC BY-ND

We know what works

Despite getting a poor report card from the international expert panel, MPI presented a virtually unmodified analysis to the IWC’s scientific committee last month. The committee identified most of the same issues and concluded it needed more time to decide whether MPI’s approach is fit for purpose. Meanwhile the IWC reiterated its recommendation, which it has been making for eight years, to ban gillnets and trawl fisheries throughout Māui dolphin habitat.

In the meantime, dolphins continue to be killed in fishing. We need to make decisions on the basis of scientific evidence available now. All of the population surveys, including those funded by MPI, show Hector’s and Māui dolphins live in waters less than 100 metres deep.

The best evidence of what works comes from Banks Peninsula, where the dolphins have had partial protection since 1988, and detailed follow-up research. This population was declining at 6% per year before gillnets were banned to four nautical miles offshore and trawling to two nautical miles. Even though there was no management of disease, the rate of population decline has dropped dramatically to less than 1% per year. If disease were a serious problem, the restrictions on gillnets would have made little difference.

A general principle in conservation is that the longer you wait, the more difficult and more expensive it will be to save a species, and the more likely we are to fail.The Conversation

Elisabeth Slooten, Professor, University of Otago and Steve Dawson, Professor, University of Otago

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Native forest protections are deeply flawed, yet may be in place for another 20 years



File 20180322 165550 14cxr7f.jpg?ixlib=rb 1.1
Current protections for native forests are hopelessly out of date.
Graeme/Flickr, CC BY-NC

David Lindenmayer, Australian National University

State governments are poised to renew some of the 20-year-old Regional Forest Agreements (RFAs) without reviewing any evidence gathered in the last two decades.

The agreements were first signed between the federal government and the states in the late 1990s in an attempt to balance the needs of the native forest logging industry with conservation and forest biodiversity.

It’s time to renew the agreements for another 20 years. Some, such as Tasmania’s, have just been renewed and others are about to be rolled over without substantial reassessment. Yet much of the data on which the RFAs are based are hopelessly out of date.




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Concerns about the validity of the science behind the agreements is shared by some state politicians, with The Guardian reporting the NSW Labor opposition environment spokeswoman as saying “the science underpinning the RFAs is out of date and incomplete”.

New, thorough assessments are needed

What is clearly needed are new, thorough and independent regional assessments that quantify the full range of values of native forests.

Much of the information underpinning these agreements comes largely from the mid-1990s. This was before key issues with climate change began to emerge and the value of carbon storage in native forests was identified; before massive wildfires damaged hundreds of thousands of hectares of forest in eastern Australia; and before the recognition that in some forest types logging operations elevate the risks of crown-scorching wildfires.

The agreements predate the massive droughts and changing climate that have affected the rainfall patterns and water supply systems of southwestern and southeastern Australia, including the forested catchments of Melbourne.

It’s also arguable whether the current Regional Forest Agreements accommodate some of the critical values of native forests. This is because their primary objective is pulp and timber production.




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Yet it is increasingly apparent that other economic and social values of native forests are greater than pulp and wood.

To take Victoria as an example, a hectare of intact mountain ash forests produces 12 million litres more water per year than the same amount of logged forest.

The economic value of that water far outstrips the value of the timber: almost all of Melbourne’s water come from these forests. Recent analysis indicates that already more than 60% of the forest in some of Melbourne’s most important catchments has been logged.

The current water supply problems in Cape Town in South Africa are a stark illustration of what can happen when natural assets and environmental infrastructure are not managed appropriately. In the case of the Victorian ash forests, some pundits would argue that the state’s desalination plant can offset the loss of catchment water. But desalination is hugely expensive to taxpayers and generates large amounts of greenhouse emissions.

A declining resource

Another critical issue with the existing agreements is the availability of loggable forest. Past over-harvesting means that much of the loggable forest has already been cut. Remaining sawlog resources are rapidly declining. It would be absurd to sign a 20-year RFA when the amount of sawlog resource remaining is less than 10 years.

This is partially because estimates of sustained yield in the original agreements did not take into account inevitable wood losses in wildfires – akin to a long-distance trucking company operating without accident insurance.

Some are arguing that the solution now is to cut even more timber in water catchments, but this would further compromise water yields at a major cost to the economy and to human populations.




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Comprehensive regional assessments must re-examine wood supplies and make significant reductions in pulp and timber yields accordingly.

The inevitable conclusion is that the Regional Forest Agreements and their underlying Comprehensive Regional Assessments are badly out of date. We should not renew them without taking into consideration decades of new information on the value of native forests and on threats to their preservation.

The ConversationAustralia’s native forests are among the nation’s most important natural assets. The Australian public has a right to expect that the most up-to-date information will be used to manage these irreplaceable assets.

David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University

This article was originally published on The Conversation. Read the original article.