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Posts Tagged native species

Save the snot eels! Rebecca McLeod Mar 02

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Hmmm, perhaps not quite as catchy as “Save the Whales”… but there are other marine species out there that we should care about too, no matter how uncuddly they may be.

At a global level, New Zealand is regarded to have some of the most well managed fisheries. Here, most exploited species are managed under the Quota Management System (QMS), which regulates the total catch for each species. But you may be surprised to know that not all marine species are managed in this way – there are some which, as a consequence of their exclusion from the QMS, are effectively “open access fisheries”.  Commercial fishers still need to have permits to take these species, but there is no apparent limit as to how many permits can be handed out.

The reason these species (think seahorses, cat’s eyes and sea anemones) are not in the QMS is because they are not considered to be desirable as fishery targets. But as times change, so do appetites for the weird and wonderful. For example, the Ministry of Fisheries has recently entered giant kelp into the QMS, as there is potential for the kelp to be used as feed in paua farms and in the pharmaceutical industry. I have blogged on this contentious issue previously.

But today I would like to draw your attention to the plight of the lowly hagfish (aka the snot eel). Whilst it appears that the western world is only interested in hagfish for entertainment purposes (an episode of Fear Factor comes to mind), they are much sought after by asian markets where the flesh is eaten and the skin made into designer leather (marketed as eel skin). The high demand for hagfish coupled with unregulated fisheries led to complete collapse of fisheries in Southeast Asia in the 1980’s, the West Coast of the United States in the 1990’s, followed by the East Coast in the early 2000’s. For now the New Zealand population appears to be in a good state, although perhaps not for long according to our sole resident hagfish expert, Dr Ric Martini. “There has never been a sustainable commercial fishery for these animals anywhere in the world, and there’s no reason New Zealand should be an exception.”

Kiss anyone? New Zealand's most common hagfish, Eptatretus cirrhatus. Photo: Stephen Wing

Kiss anyone? New Zealand's most common hagfish, Eptatretus cirrhatus. Photo: Stephen Wing

Four years ago one company, Tuere Fishing Ltd. of Christchurch, began small-scale commercial hagfish fishing in New Zealand coastal waters. Although the venture hasn’t been wildly successful, it continues to operate and interest in Korea has been sufficient to attract a second company operating out of Tauranga. Dr Martini is concerned that the fishery here is currently unregulated. “The startup fishery got the attention of the Korean buyers, and now others are moving into the market. Without regulatory oversight, we risk a “gold-rush” fishery, where multiple companies capitalize heavily to maximize their catch.  Experience suggests that the boats will get larger and more numerous and landings will skyrocket while the catch per unit effort declines, and then in 3-5 years the fishery will collapse.”

But who cares about a stinking, slimy fish that lives at the depths of the ocean?

Although very little is known about the biology of our most common species, Eptatretus cirrhatus, it appears that they play a key role in deep sea ecosystems – as a food source for large fish and marine mammals, as key scavengers of carrion and as aerators of deep sea sediment. Dr Martini has counted upwards of 325,000 hagfish in a square kilometer! Yes, you read this correctly, three hundred and twenty-five THOUSAND. Surely at densities this high, hagfish must have a high impact on their habitat and interact with other species that live there.

The likelihood of sustainable management of a fishery increases with the knowledge of the target species. Unfortunately for hagfish, very little is known about even the most basic life history characteristics such as growth rates, breeding grounds, embryo development, age structure of the population, or natural mortality rates. But we do know that they reproduce slowly – females produce only 20-40 large eggs that take 1-2 years to produce, and another year to develop into young hagfish. So they are certain to be at least as vulnerable to overfishing as the pelagic sharks – and fisheries for sharks have proven to be extremely difficult to manage sustainably. It would be prudent, then, to treat the burgeoning New Zealand hagfish fishery with great care.

A good place to begin, according to Dr Martini, would be to undertake some baseline surveys around New Zealand to estimate the size of the population. This information, combined with improved knowledge of basic life history characteristics would form the basis for management of the fishery. However, there are steps that can be taken in the meantime whilst that information is being collected. Faced with similar regulatory uncertainties, the Canadian Department of Fisheries and Oceans has classified hagfish as an “experimental fishery.” This involves issuing a limited number of permits (for example, only one vessel is permitted to fish for hagfish in water offshore from British Columbia), making escape holes in pots mandatory to allow juveniles to escape, collecting catch data, and encouraging collaboration with scientists to research the life history of these animals and to detect any changes in the hagfish population as the fishery operates. The Canadian program is an appropriate model for New Zealand to adopt, as it would allow the fishery to develop under tightly controlled conditions that protect the resource.

As pressure mounts on the New Zealand hagfish fishery it is important that the Ministry of Fisheries reconsider the status of hagfish in our waters, and move towards regulating the extraction of this vulnerable species – experience shows that if we continue on our current course, this fishery is headed for collapse!

Solved: the problem of the cross-dressing frogs Rebecca McLeod Nov 03

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The global plight of amphibians received a lot of attention last year – the official Year of the Frog. Just in case you missed it, amphibians are currently undergoing a worldwide extinction crisis, with 32% of all species threatened with extinction. The reasons for this sorry state of affairs are believed to be many – loss of habitat, increased incidence of disease, competitive exclusion from introduced species, climate change, increased UV radiation, pollution, predation, and overexploitation.

But I don’t want this to be yet another story documenting the alarming state of our global ecosystem. Recently I attended a very inspiring seminar given by Jen Germano – and it gave me hope that innovative approaches to conservation might just lead to some species recovering to healthy levels. Germano is a doctoral student at Otago University who is about to submit her PhD thesis under the supervision of Drs Phil Bishop and Alison Cree, and in collaboration with Landcare Research scientist Dr Frank Molinia.

A Maud Island frog (Leiopelma pakeka)

A Maud Island frog (Leiopelma pakeka)

Germano has spent the past 5 years focusing on ways to improve the success of conservation efforts for New Zealand native frogs (genus Leiopelma). New Zealand currently has 4 species of native frog – all classified as endangered – and 3 species that are believed to be extinct. Our frogs are from an archaic lineage and have a few traits that set them apart from those inhabiting other parts of the globe. Most notably, New Zealand native frogs do not have external eardrums, and therefore do not croak, instead communicating with chemical signals. There is also no easy way to tell males and females apart – there are no colour, size, or other morphological differences between sexes (hence the crass but attention-grabbing headline!), and this has posed problems for those trying to save them.

Jen Germano with some Maud Island froglets (babies)

Jen Germano with some Maud Island froglets (babies)

A proactive approach is being taken to frog conservation in this country, and many organizations are involved with efforts to breed and translocate frogs, to encourage sustainable populations. With other endangered species captive breeding populations have provided a form of “insurance”, but one major problem has arisen for NZ frogs – whilst our zoos have put a great deal of effort into starting captive frog colonies, they haven’t been able to successful breed any of the native frogs. This setback led Germano to develop a method for telling apart males and females based on hormone levels in their urine. The method is relatively non-invasive, and has allowed Germano and her colleagues to sex Maud Island frogs with 94% certainty. The ability to identify the sex of our native frogs is a big leap forward for captive breeding and translocation programs, as now they will be able to provide even sex ratios, which will hopefully lead to higher breeding success. Germano has been passing on her skills to staff at Auckland Zoo and Orana Park, where captive breeding programs are underway.

Germano explains that until recently, very little was known about the basic life history of our native frog species. “While I was working on frog translocations for my Masters project, I saw many of the problems that other scientists were facing when working with these frogs and it was obvious that there were huge gaps in the knowledge that we had for the basic biology of our endemic species and in the information that managers and scientists needed to conserve them.” A large part of Germano’s thesis involved determining the breeding season of Maud Island frogs – and surprisingly she found it is likely to occur in mid winter. Germano has also discovered that Maud Island frogs have incredibly low sperm counts, which may also help to explain why their numbers are so low.

With her PhD thesis soon to be submitted, Germano will be heading to Memphis Zoo in the USA to begin a position as a postdoctoral researcher in amphibian reproductive biology. But she can leave with the satisfaction of knowing that the Maud Island frogs and those working to save them in a much better position than when she began her studies.

The largest remaining population of native frogs in NZ exists on Maud Island, a predator-free island in the Marlborough Sounds.

The largest remaining population of native frogs in NZ exists on Maud Island, a predator-free island in the Marlborough Sounds.