Re: Sea Hares - mass mortality

September 28, 1999
From: Anne DuPont

Dear Bill,

The Sea Hares I described in my message appeared to be almost dead. When I picked up one, it did not try to move, but it did ink me. I will send you via snail mail all the photos I took that day to help you with identification.

Also, here is a response I received from Paul Johnson.

Dear Ms. DuPont,

Thank you for sending me your question - it's always nice to find someone interested in sea hares. By your photo it looks like you found Aplysia dactylomela, a very common species in Florida waters. I did my undergraduate work at the University of Miami and even got over to Captiva a few times. By their size, large numbers, and the time of year, it seems most likely that they were dying of natural causes. Most Aplysia species have an one year life cycle and the Florida A. dactylomela seem to have two population waves per year - one that reproduces in July and August then dies and the other that reproduces in February and March then dies. After laying their egg masses (containing millions of eggs) the dying adults just wash up on the beaches in large numbers. You seem to have been fortunate enough to have observed the end of some successful sea hare lives. Their young should be back in great numbers next year.

Thank you and Best Wishes,

Paul Micah "PM" Johnson
University of Washington, Dept. of Zoology
Kincaid Hall, Box 351800 (RM 204)
Seattle, WA 98195-1800

Hope this helps,
Anne Dupont.

DuPont, A., 1999 (Sep 28) Re: Sea Hares - mass mortality. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Anne,
Thanks for the message and I see that Paul also thinks the deaths were probably a natural phenomenon. I look forward to receiving the photos. Hopefully they will help us identify the species. I must say from your original photos that the animals do not look like Aplysia dactylomela, which is usually characterised by large black rings in its colour pattern. See earlier message on mass mortality of Aplysia dactylomela in Florida, and photo of animal from the Bahamas.

Bill Rudman.

See later message from Anne Dupont for further photos and discussion on its identity - Bill Rudman.

Rudman, W.B., 1999 (Sep 28). Comment on Re: Sea Hares - mass mortality by Anne DuPont. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


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