Collecting sites in Australasia

Related messages


Sea Hare abundance on GBR

March 8, 2002
From: Julie Marshall

Dear Bill,
In response to Cathryn Clarke's request for information on the abundance of sea hares on the GBR she can find information for Aplysia dactylomela, Dolabella auricularia and Dolabrifera dolabrifera for Heron Island in Marshall & Willan's book Nudibranchs of Heron Island. We list the numbers found in different sites on the reef over a number of years for each of these species. Since the book was published I have also found Aplysia extraordinaria at Heron Island but this was a rare sighting.

Best wishes,
Julie Marshall

juliemarshall@netspace.net.au

Marshall, J., 2002 (Mar 8) Sea Hare abundance on GBR. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6388

Thanks Julie,
Bill Rudman

Sea hare abundance on the GBR

March 5, 2002
From: Cathryn Clarke

Dr. Rudman,
I am applying for a research permit to collect Sea Hares from the Great Barrier Reef. The GBR Marine Park Authority has asked me to contact some of the experts in the field to get estimates of abundance of the more common species. I thought perhaps someone in your Forum may be able to help. Does anyone have an idea of the abundances of Aplysia dactylomela, A. extraordinaria, A. juliana, and Dolabella auricularia? I would appreciate any information as there isn't much published information on this aspect.

Thank you,
Cathryn Clarke
Masters Student
James Cook University

Cathryn.Clarke@jcu.edu.au

Clarke, C., 2002 (Mar 5) Sea hare abundance on the GBR. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6358

Dear Cathryn,
You don't give any indication of the numbers you wish to collect or what you are planning to do so its a bit hard to make a value judgement. However the species you list are all common species with a widespread geographical distribution. As you say there is little published on their abundance and distribution in Australian waters. Like most species of Sea Hares, they are at times locally abundant and other times absent. The species you list all produce enormous quantities of eggs which develop into free-swimming larvae which spend some weeks in the plankton. They grow to sexual maturity in less than a year. If you look at the page on Mass Mortality, you will see that it is common for them to die in large numbers. All the species you list are found on the Great Barrier Reef. In my judgement, I cannot imagine that collecting a few animals for research purposes would have any affect on their natural populations. From Richard Willan's comments on Heron Island, I suspect he would feel the same way.

If anyone with local experience would like to agree or disagree with my comments I am sure Cathryn would be grateful.
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Mar 5). Comment on Sea hare abundance on the GBR by Cathryn Clarke. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6358

Re: Sea Hare sites in Australia/New Zealand

May 19, 1998
From: Kirsten Benkendorff

With regard to P.M. Johnson's query about sea hare populations in Australia, I have found that several species are quite common along the Wollongong. A. juliana is particulary abundant on the walls of man-made ocean swimming pools in September. A. sydneyensis can also be quite common. I also know of 4 populations of Dolabrifera dolabrifera (1 at Bellambi and 3 along Bass Point) but these only have an average of 30 individuals.

Cheers Kirsten

Kirsten Benkendorff

kb06@uow.edu.au

Benkendorff, K., 1998 (May 19) Re: Sea Hare sites in Australia/New Zealand. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/139

Re: Sea Hare sites in Australia/New Zealand

April 21, 1998
From: P.M. Johnson

Dear Dr. Rudman,

Thank you very much for your quick reply to my questions. I've looked at the marine lab web sites you suggested and I will also be contacting Drs. Willan and Steinberg for more info.

Thanks again for your help,

P.M. Johnson,

pmj@u.washington.edu

P.M. Johnson, 1998 (Apr 21) Re: Sea Hare sites in Australia/New Zealand. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/138

Re: Sea Hare sites in Australia/New Zealand

April 20, 1998
From: Richard Willan

Dear Bill,

This message is in reply to P.M. Johnson's request for information on the availability of sea hares (particularly Aplysia spp.) in Australia and New Zealand in August and September. Both the localities I mention below are the sites of marine research stations.

Assuming they want 40+ animals to study, I would recommend Heron Island in the southern section of the Great Barrier Reef because he would be guaranteed to collect that number of adult Aplysia dactylomela at the reef crest at that time of year. Numbers do go up and down from year to year, but there is never none. The student could collect Dolabella auricularia on Heron Reef too.

I would not recommend Leigh, north of Auckland, because densities are plunging very rapidly towards zero at that time of year (in 1976 I found no animals between August and December) because of storm-related mortality, low seawater temperatures and dwindling algal food.

Cheers,

Richard Willan

richard.willan@nt.gov.au

Willan, R., 1998 (Apr 20) Re: Sea Hare sites in Australia/New Zealand. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/137

Sea Hare sites in Australia/New Zealand

April 17, 1998
From: P.M. Johnson

I'm a PhD student in zoology at the University of Washington working on defence in sea hares, particularly the ink and opaline systems of Aplysia. I'm looking for a site in Australia or New Zealand to do some field work on sea hares, particularly Aplysia species. Does anyone know of sites were they can be found during the months of August and September?

P.M. Johnson

Department of Zoology
University of Washington,
Seattle, Washington, U.S.A.

pmj@u.washington.edu

Johnson, P.M., 1998 (Apr 17) Sea Hare sites in Australia/New Zealand. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/136

Sea hares are often common in Australia and New Zealand but I'm afraid the time you are suggesting (August-September) is our winter, which is not the best time for many seasonal intertidal and shallow water animals. I have contacted Richard Willan who studied the ecology of Sea Hares at Leigh Marine Laboratory, in New Zealand some years ago and you will find his reply above. If you can change the times you are likely to visit then Leigh, just north of Auckland would be a worthwhile place to work. Aplysia dactylomela is abundant there over summer and autumn (February-June), and other species such as A. parvula and A. juliana not difficult to find nearby.

Another possibility would be for you to contact Dr P. Steinberg, School of Biological Science University of New South Wales, Sydney who is interested in the ecology of chemical defences against herbivores in marine algae and in marine plant/herbivore interactions. He has had students working on aspects of Aplysia biology and keeps aquarium populations.

If you are interested in Richard Willan's suggestion about Heron Island contact details are available at the University of Queensland's website.

Rudman, W.B., 1998 (Apr 17). Comment on Sea Hare sites in Australia/New Zealand by P.M. Johnson. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/136