Report from Southern Belize
John_Bruno at brown.edu
Fri Jan 22 12:57:48 EST 1999
Dear Coral Listers,
Below is a brief report from a recent survey of Southern Belize (January
5-12 1999) to assess the effects of last summer's coral bleaching episode
and Hurricane Mitch. Hopefully this will compliment previously posted
reports from the northern and central portions of Belize The team was led
by Dr. Mark Bertness, from Brown University, who has been working in
Southern Belize since 1982.
1) Hurricane damage: The only reefs that displayed any evidence of
hurricane damage were the shallow reefs on the exposed side of the silk
keys, which are about 300 m behind the crest of the barrier reef. At
depths of 1 - 5 m, the disturbance was severe and there were very few
living corals. The substrate was dominated by A. palmata rubble and algal
cover (Turbinaria and Dictyota) was high. However, the corals (mostly
Montastrea spp.) of the protected side of the silk keys appeared
unaffected. We also examined four sites in the 'lagoon' at varying
distance from the reef crest including Laughing Bird key and Cepio key
which appeared to be unaffected by Mitch. Locals at Placencia reported
that max wind speeds from Mitch were only about 40 - 50 mph in S. Belize.
2) Coral Bleaching: All summer long we received reports from locals of
severe bleaching in the lagoon and expected to see alot of dead corals in
January. In general A. tenuifolia and Millepora colonies were almost all
dead. Because most were still in growth position and locals reported that
these species bleached extensively in July and August we suspect that
bleaching and not hurricane related stress was the main source of
mortality. Most colonies of Diploria strigosa and clivosa, P. astreoides,
Siderastrea siderea, and Mycetophyllia spp., were still totally bleached,
although very few were already dead. However almost all colonies of
Porites and Montastrea were healthy and we did not find any Montastrea
colonies that appeared to have died in the last few weeks/months. In fact,
the lagoon reefs of Southern Belize still have by far the most healthy
populations of Montastrea we have seen anywhere in the Caribbean.
3) Diadema: only 2 individuals were seen!
4) Juvenile corals were also almost non-existent, even for species that
often display high levels of recruitment elsewhere in the Caribbean (e.g.
Agaricia agaricites and Porites astreoides).
5) Acropora spp.: We were surprised by the almost complete absence of
living Acropora colonies at all five surveyed sites. Only two years ago
all three species were relatively abundant. This year we did not see a
single colony of prolifera, and only found 1 or 2 very small colonies of
palmata and cervicornis. However, dead and overgrown skeletons of all
three species, often still in growth position, were relatively abundant.
This was especially true at Laughing Bird key, where the shallow forereef
(1-5 m depth) was totally dominated by erect but dead palmata skeletons.
We suspect that white band disease may be the culprit.
6) Gorgonians: A majority of colonies of Gorgonia ventalina appeared to be
infected with the so called gorgonian pathogen.
John F. Bruno
Department of Ecology and Evolutionary Biology
Providence, RI 02912
email: John_Bruno at Brown.edu
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