Collaborative Projects > Water - Case Studies > Spotted Handfish

Spotted Handfish

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Aim

The aim of the investigation of Threatened and Endangered Group Two was to determine and isolate the factors which lead to the current demise of the chosen native aquatic species, and also to research the methods employed to counteract the problem.

Introduction

The Spotted Handfish, Brachionichthys hirsutus, is a species of anglerfish endemic to Tasmania and the Derwent Estuary. Once the most common of all inshore species of Handfish, it is no longer so populous. The first indication of problems within the population was in 1989 – a PhD student conducted a survey to locate the spotted handfish. ‘He went diving and couldn't find any of the spotted handfish, not even in the areas where they used to be common.’ (Green 2004). Since then, populations of these fish have been endangered; but it was not until 1996 that they finally became recognised and classified as critically endangered. In 1998, a major recovery plan was implemented to help bring back the species from the brink of extinction. The main causes for their population decline were determined, i.e. The Northern Pacific Sea Star, Asterias Amurensis, destroying their habitat. This problem was then directly addressed; the method of which will be explored later in this report.

Method

Have a phone call placed to all institutions known to study or have studied the Spotted Handfish. Advice then should have been followed to determine the most informed person in the field. Obtain their number and call them requesting an interview: having met them in person, questions that have been devised should have been asked and take a photo, if they authorise. Under their guidance, obtain the relevant Scientific Journal research report and further media release information from the recommended sources.

Interview

The interview was conducted on the 11th May 2004 with Mark Green, CSIRO Researcher in the field of Marine Ecology. Also: Site Dive Officer; Acting Divisional Dive Officer; EEO Contact Officer. Australia's most knowledgeable person in regards to the Spotted Handfish.


Q: What would be the impact upon society and other organisms if the spotted handfish was to become extinct?

A: People have always asked the question ‘Why do we need to save it?’ We think of how the Dodo became extinct, and in retrospect decide that it had no real impact upon us as a whole. We're ok, our populations haven't suffered. The real reason why we want to conserve this is to maintain biodiversity.

We humans could survive just about anything; we are a very adaptable species, to any environment, to isolation. But by letting any species to become extinct, you reduce the pool of potential organisms that already do or may help us in the future, such as for pharmaceutical benefits. Also considering the recreational divers and that industry, people want to see these fish in their natural habitat. There's also the commercial aspect, and us humans being the self-centred people we are, we'd try to make the most of its existence. They also could be used as an indicator species as to the health of the Derwent. Because they live on the bottom, if they are not present then we know that the Derwent estuary bottom is not in good condition.

I'm not really sure of the impact upon other organisms, because as a species they are quite rare, even in areas where they are “common”. This is because they have a small distribution; on most diving trips I've seen say two fish—on one occasion I saw eighteen, but that was in breeding season. But if there are so few and they are a small fish, whatever they feed upon isn't going to suddenly go into a population boom because of lack of control. But then again, we really don't know—if you take the Dodo's out and put cats in the bush… there may be a huge impact.

Q: When did it become apparent that the spotted handfish populations were dwindling?

A: The first indication was through a PhD student named Neville Barret, and that was in the eighties. He went diving and couldn't find any of the spotted handfish, not even in the areas where they used to be common. In 1994 some survey work was done on Asterias Amurensis—the Northern Pacific Sea-Star, for the Tasmanian Museum. They went diving where the sea-stars were abundant and only two handfish were seen—this was where they were supposed to be common. And so during 1996 it was officially classified by Federal Government's Australian Nature Conservation Agency (ANCA) and by the International Union for the Conservation of Nature (IUCN) as Critically Endangered. The Marine Conservation Legislation ordered some further investigation, so Neville Barrett did some work for the Department of Environment on the fish, but he only found five specimens. By then all the government money ran out and they couldn't do any more work on it. But by the end of 1996 they got more funding and the studies went on. They only found one colony in the South Arm area. The abundance of Asterias Amurensis was making things look a little fishy—excuse the pun—wherever it was abundant the handfish was not. He helped out and found some other colonies in Frederick Henry Bay and on the South Arm Peninsula.

Q: What is being done to fight the problem of the Northern Pacific Sea Star, Asterias Amurensis, and restore populations of the spotted handfish?

A: When we found the first population, we monitored it. Then we found that a native type if sea squirt, or ascidian, was what the handfish wrapped their eggs around. ‘Stalked Ascidians’ we called them, because they had a small upright stalk and that's what they wrapped their eggs around, as the mother guarded them for two months until the embryos hatched. There were some of the sea stars around. Then we monitored them some more: the sea star density quickly increased up to a high density of up to one per two square metres. And they were feeding on just about everything, including the stalked ascidians. But the real problem was that there was now nowhere left for the handfish to lay their eggs. So to try and fix the problem we started a captive breeding program in an aquarium, breeding 156 individuals, and we devised these plastic stalks, with little discs on one end to help them stay upright. In 1998 we tried these at two different sites, with the artificial substrate [plastic stalks]. By 2000 we noted that there was only 25% of the original number of the adult population left—but there was a huge increase in the number of juveniles. In 2002 the density of adults went back to the original amount as in 1998, as well as having a very strong population of juveniles.

But we cant assume that the Asterias Amurensis was the only problem by causing the destruction of habitat. The Northern Pacific Sea star has been around since the 1970's and the decline in numbers of handfish were not apparent nor of concern then, it was only in later years that this appeared to be the problem.

Humans are probably a large contributing factor too, the pollution, the raw sewage that used to be pumped out into Sandy Bay, and from the Zinc Works. They destroyed a lot of the biodiversity.

Frederick Henry Bay was thought to have the best population of Handfish. Maybe the numbers of spotted handfish also fell to some disease such as what we are seeing in the Tassie Devil today. But if no-one pays us, we can't do the research. So the answer to that question may remain a mystery until we get some more funding.

Q: How did you become involved in researching the spotted handfish?

A: Well, I was working at the CSIRO on sharks. A colleague of mine, Barry Bruce, was researching sea stars. He was also on the handfish recovery team. Basically he just said, ‘Why don't you join me!’

Q: Where has this investigation taken you? Has any of your work been published?

A: Because the spotted handfish has only been found in the Derwent, D'Entrecasteaux Channel and Frederick Henry Bay, and they can't be found anywhere else in the world except here in Tasmania, I haven't gone anywhere overseas… the East Coast is about as far as we got. Unfortunately no trips to the Gold Coast!

As for my published work, there have been a few bits and pieces in news articles from media releases, particularly if you look it up on the CSIRO website. There was one bit published in the 1996 Scientific Journal, or what we call ‘grey literature’, as a report which is in the Library. That basically is a compulsory report we have to do when the Environmental Protection Act in the ACT gives you funding – they want to see what you've been doing with it. It's under legislation that if a species is on that threatened or endangered list, a recovery plan is produced for that particular species.

So basically, to get the report, we do the research, find the problem and investigate it. We used most of the funding for our artificial spawning substrate program, by supplementing the destroyed handfish habitat with the plastic stalks. This provides a critical structure essential for handfish reproduction. It's good if you improve the habitat for the other organisms living in that same habitat during your studies. We translated some algae to rehabilitate the degraded seabed and provide natural spawning habitat for handfish. But at the moment, there's no money, so there's no recovery program and no monitoring of the habitat. The latest recovery plan of habitat restoration for the handfish hasn't been signed off by the minister in Canberra, so that's why nothing is being done about it now.

Collaborative Report

FACTORS WHICH LEAD TO THE CURRENT DEMISE OF THE SPOTTED HANDFISH:

The primary cause for the decline in Spotted Handfish (Brachionichthys Hirsutus) numbers is the destruction of spawning substrate. Secondary causes include the destruction of habitat and deterioration in water quality. The Spotted Handfish has a naturally low fecundity compared to other species of bony fish – only 80 to 300 eggs are spawned by a female annually. The eggs are laid, encapsulated in a small tube of membrane, which is then wrapped around a small vertical structure on the sea floor, such as a piece of seaweed, seagrass, sponge, or more commonly; a species of sea-tulip called a Stalked Ascidian. Here the eggs remain, guarded by the female for approximately seven weeks, as the embryos develop; during which time they are very vulnerable, particularly during storms.

Here a problem is encountered. The introduced Northern Pacific Sea Star, Asterias Amurensis, feed voraciously on almost all bottom vegetation and molluscs. Seagrass and seaweed are likely to have become less abundant due to water degradation, as a result of: industrial pollution, sewage, stormwater drains and siltation as a consequence of increased surface run-off and land clearing. In the D'Entrecasteaux Channel, historic scallop dredges destroyed wide areas of bottom vegetation. Most importantly, through this, the destruction of breeding ground prevents the Spotted Handfish from reproducing. Water pollution also destroys biodiversity within the Handfish's habitat. It is unknown whether heavy-metal water contamination has any adverse effects on the Spotted Handfish.

METHODS EMPLOYED TO COUNTERACT THE PROBLEM:

A Recovery Plan was implemented in 1998 to rectify the problem and restore Handfish Populations. This involved:

• Population monitoring.
• In 1999, 156 captive-bred juveniles were released.
• Small plastic stalks were successfully devised as fixtures in which the Handfish could spawn around, called Artificial Spawning Substrate (ASS). These were impregnated into the sea floor: it was noted that there was a major population increase after two years.
• Future plans include the rehabilitation of sea-beds in the Derwent. A successful trial test was conducted in 2002 to relocate algae suitable for handfish spawning. However, there is insufficient funding to implement this plan.

Discussion

Given that there was no experimental research, a critical evaluation of the method is not relevant.

When the initial investigation began, it was advised through WebCT that Taroona Fisheries should be contacted, as they were currently studying the Spotted Handfish and conducting a breeding program. Immediate correspondence rectified the advice, indicating that studies had been terminated at the Tasmanian Aquaculture Fisheries Institute, (TAFI), in 2002 due to lack of Government funding. Thus, no on-site investigation could be undertaken, and an alternate practical study had to be remedied.

An interview with the most knowledgeable person in the field was then searched for. Contact with both CSIRO Marine Research Faculty and TAFI advised that the two individuals who had conducted the study; Barry Bruce and Mark Green - were those to contact in aid of further information on the Spotted Handfish. Project Manager, Barry Bruce, recommended Mark Green as he conducted most of the research, and had a broader knowledge on the issue.

Mark Green was very enthusiastic and helpful, taking part in the interview, and forwarding me the ‘grey literature’ report written by his colleague and himself.

Conclusion

Populations of the Spotted Handfish are slowly recovering as a result of the Recovery Plan implemented in earlier years. The restoration of breeding ground was a major contributing factor to this result. However, further habitat restoration is important, but this cannot occur until the second Recovery Plan, enforcing this, is approved by the Federal Government and funds are allocated.

The outcome of this case study was the increased awareness and education of three native aquatic species in Tasmania, their biology, causes for endangerment and plans employed to counteract this problem.

References

CSIRO Australia, “Media Release - Handfish steps back from the brink of extinction.” (28 Jan 1998)
www.marine.csiro.com.au

CSIRO Australia, “Media Release - Walking fish reach another milestone.” (28 Jun 1999)
www.marine.csiro.com.au

CSIRO Australia, “Information Sheet - Australia's first endangered marine fish.” (August 1998)
www.marine.csiro.com.au

CSIRO Australia, “Information Sheet - Australia's Ocean facts - Marine Biodiversity.” (November 1998)
www.marine.csiro.com.au

Green, M., Bruce, B. (2002) “HANDFISH - a unique, Australian family of anglerfish.” Scientific Journal
(email from Green, M.)

Green, M. (May 11, 2004) Personal Communication.

Acknowledgements

Mark Green

CSIRO, MARINE RESEARCH
DEPARTMENT OF PRIMARY INDUSTRY, WATER AND ENVIRONMENT
TASMANIAN CONSERVATION TRUST