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of Marine Life, Census of Coral Reefs Expedition to
French Frigate Shoals (October 2006)
Scientist: Russel Brainard
Target Habitats: Water column
Target Organisms: Planktonic larvae and
"Light traps" of various designs have been used
for years to collect marine fishes and invertebrates, especially
their larvae and other zooplankton at night.
taxa will include various planktonic crustaceans such
as mysids, cumaceans, isopods, as well as marine worms
small fish get caught, there will be little chance of
mortality and they will be released). Many
planktonic organisms navigate by and are attracted
to light, and this method takes advantage
of that fact. Light traps can be deployed by tying
them to any other structure that is going to be in
or they can have their own bottom weight. The light
traps will either be attached to the ship or deployed
for careful placement of the light trap anchors.
The traps themselves will not be on the bottom. It is best
hang in the water column just below the surface.
will need to be deployed for only a couple of hours
at a time
after sunset. The organisms they are intended to
catch will be in the upper meter or so of the water after
usually for only a few hours. Although a large
variety of designs have been used successfully over the
use a simple and commercially available design
that consists of a black PVC body with four openings
funnels. Plankton enter via the wide end of the
funnel and become
trapped within the PVC body. Lighting is achieved
inserting either disposable cyalume "light sticks" or a small
underwater flashlight into the trap. "Aquatic Light
Trap" have been used successfully in the Caribbean.
(Doherty 1987; Holmes & O’Connor 1988;
Watson, et. al 2002)
illustrations above by Mark J. Rauzon
Back to collection methods
activities of the expedition.
or semi-daily personal journal entries by
in the expedition. These journals do not necessarily reflect
the positions of any of the agencies connected with this
Interviews with expedition participants, scientists,
vessel crew, educators, etc.
Highlights or special information such as interesting
discoveries, articles or related research.