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Red Grouper Habitats in Florida Bay
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Red Grouper:
A red grouper waits patiently just outside his hole while cleaning shrimp pick parasites from his head.
Grouper Hole:
Hogfish, angelfish, corals, crabs, shrimp, anemones and a wide variety of other organisms
live in and around this red grouper hole.
Near the Hole:
Just a few meters away from a red grouper hole, the diverse biological community gives
way to a landscape dominated by sea grasses and algae.
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Kathy Scanlon was invited by Florida State University (FSU) biologists Chris Koenig and
Felicia Coleman to study the geologic aspects of red grouper habitats in Florida Bay
for two weeks in August. Aboard an 18-ft outboard motorboat provided by NOAA and
using SCUBA gear, the three scientists and Tommy Sheridan, an undergraduate field
assistant from FSU, located, photographed, sampled, described and catalogued several
red grouper holes in the shallow waters north of Long Key in the Florida Keys.
Red grouper are known to excavate under hard objects and keep hardbottom areas
clean of sediment and debris. We observed a diverse ecological community in the
immediate vicinity of the red grouper holes, including lobsters, crabs, shrimp,
anemones, corals, and numerous fish species. Sea grasses and algae were observed
a few meters away from the holes.
Similar red grouper habitats have been observed in deep water (80 m) near
the shelf edge, where we have collected sidescan-sonar imagery and views with
a video camera mounted on an ROV. The larger red grouper at these sites are a
heavily targeted commercial and recreational fishery species. What happens to the
benthic biological community living around a red grouper hole if the red grouper
is removed? How quickly does sediment fill the hole? Do the other species leave?
Are the red groupers the only residents moving the sediment? Does groundwater
seepage play a role? Because it is much easier to make observations and
'manipulate the ecosystem' in 3 m of water than in 80 m, these questions are
being tackled first in Florida Bay before applying what we learn to the deeper,
less accessible red grouper habitats.
Kathy reports, "Although we had permits to kill the grouper, we did not.
We experimented with caging them out of their hole or caging them in a place
with no hole to see what they would do and how quickly. The cages are about
4'x4'x2' and allow free movement of smaller species through them. We intended
to leave the grouper caged for no more than 2 weeks, but a little hurricane got
in the way of the release trip. I think they ended up caged for 3 or 4 weeks,
but seemed to be OK." The Marine Conservation Biology Institute (MCBI) funded
the work as a pilot study to assess the feasibility of a larger, better-controlled
project. The MCBI is a national nonprofit tax-exempt
organization dedicated to advancing the multidisciplinary science of marine
conservation biology. Felicia Coleman is presently writing a proposal to seek
additional funding.
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October 2000
in this issue:
Florida Bay Red Grouper
Divers at Turners Falls
Long Island Sound
cover story:
Boston Harbor Clean-Up
Sea Floor Mapping DVD-ROM
Santa Cruz Shark Festival
Natural Systems Restoration
Mapping Tools for Fisheries
Alaska Geologic Mapping
Coral Reef Task Force
Gulf of Mexico Sediments
Viking Celebration
Iceland Lecture
Congratulations
Visitors
October Publications List
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U. S. Department of the Interior | U.S. Geological Survey
