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

Factsheet

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