Spawning

Ernesto Weil eweil at caribe.net
Mon Sep 9 14:35:03 EDT 2002


Hi everyone. Here I have included observations on the spawning event
of August in La Parguera, sothwest of PRico to complement the information
posted by Edwin for Culebra, in the eastern coast of PRico.

A gradaute student and I started our observations in the field on the
evening of August 27th. We placed spawn collectors (new design using large,
plastic funnels, with a collector bottle at the tip, placed on top of the
colony surface and tied down with nylon rope and nails so they did not move
at all). These collectos were left in the field until early the next
morning.

We got in the water in the shallow back reef area of San Cristobal reef in
La Parguera right after the sunset (19:30 h) and got out at 22:15 h. This
site was selected because there are several very large colonies of Diploria
strigosa and D. clivosa. which we were most interested in seing spawning
this time around. There are also many colonies of the three Montastraea spp.
and other important Caribbean corals.

On the evening of the 27th, only a few colonies of the octocoral P. porosa
spawned at 20:30 h. The spawn appeared to be individual eggs (no eg bundles)
released by the extended polyps. Many eggs were released by the same polyp
over a period of 15-20 min. Nothing was found in the collectors left on top
of the coral colonies the next day. On the evening of the 28th, most
colonies of the octocoral P.porosa spawned at 20:30 h and lasted about 20
minutes. Again it appeaded to individual eggs being released. Montastraea
franksi spawned at 21:30 h and the other two (M.annularis and
M.faveolata) after 23:00 h. Nothing happened with the Diplorias. The
collectors were left over night in the field on colonies of Diploria
spp. No spawnimg  that night. Observations in the bay of Mayaguez during the
early morning hours of the next day indicate that the water was full of
pink eggs, presumably released the night before by the Montastraea sp and
other species.

We did not dive on the evening of the 29th but we placed the collectors and
checked them the next day.  We got a substantial amount of spawn in
collectors placed on M.annularis, Mfranksi, Mfaveolata, and D.clivosa, but
nothing was found in those from D.strigosa.

Saludos!

EW

Ernesto Weil, Ph.D
Associate Professor
Dep. Marine Sciences
U. of Puerto Rico
PO BOX 908, Lajas PR 00667
Ph. (787) 899-2048 x. 241
Fax (787)899-5500/2630




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