[Coral-List] Looking for fish and urchin data
dennis.hubbard at oberlin.edu
Tue May 17 11:58:37 EDT 2016
Greetings to all:
I thought I'd change the tome of the recent postings and ask my colleagues
for some help:
For context, In the late 1970s, we did what I believe is still the most
complete carbonate budget study for any reef. The study took place at Cane
Bay on the NW shelf of St. Croix. This included extensive reef surveys,
reef coring and measurement of sediment export using several different
methods that yielded similar results (including during a CAT 5 hurricane).
Recently, we started re-doing this study to quantify the changes over the
past 35 years. We have totally resurveyed the shore-parallel chain
transects (10-m plan length) at 10-m horizontal increments from shore to a
maximum depth of 40m. From this, we determined that carbonate production is
down by nearly 50%. On the bioerosion side, we did an urchin survey at the
same sites using Chris Perry's protocol and had Jeff Miller come in and do
a very good grazing fish survey that allows us to compute grazing-related
bioerosion by reef zones and depth. We also have Judy Lang's 1999 AGGRA
data for grazing fish at Cane Bay. Finally, we recently completed (Liz
WHitcher's Senior Honors Thesis) a detailed study that determined
depth-related bioerosion using corals for which we could constrain their
date of death to within 2 months in 2005.
So, while we feel very good about our determination of various elements of
the budget more recently - and feel that we have the production side well
in hand, we want to examine our assumptions about grazer densities and
efficiency in the late 1970s. Do any of you have data for Caribbean
parrotfish and/or urchin abundances back in the 70s (i.e., before the
urchin die-off) or at any other time for parrotfish... and any other other
grazers that would remove substrate in the act of grazing? Likewise, might
any of you be aware of papers that would contain sufficiently tabulated
data that could be used in Chris Perry's protocol to compute comparative
bioerosion data for the 70s or any time between then and now (we might be
able to create a time series that could be used to hindcast densities in
the late 70s)?
For obvious reasons, the ideal data would be from Cane Bay.... or the north
shore of St. Croix. However, even data from elsewhere in the Caribbean at
analogous sites could potentially have value.
Thanks in advance for any help the listseve lurkers might be able to
provide. I hope to see you all in Hawaii.
Chair, Dept of Geology-Oberlin College Oberlin OH 44074
* "When you get on the wrong train.... every stop is the wrong stop"*
Benjamin Stein: "*Ludes, A Ballad of the Drug and the Dream*"
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