The Spot Prawn Fishery: A Status Report - Earth Economics

The Spot Prawn Fishery: A Status Report
Spot prawns typically inhabit rocky or hard bottoms,
including reefs, coral or glass-sponge beds,
and the edges of marine canyons. In part, species
abundance is determined by the natural productivity
levels characteristic of an area. Distribution
is a function of the temperature and salinity of
the water, and the animal’s developmental stage.
Immature shrimp are able to tolerate greater ranges
in both these factors and are found in shallower
depths than adults. Common depth ranges extend
from the intertidal to 487 meters (1,607 feet). Spot
prawns are typically found at depth’s of between
198 and 234 meters (653–772 feet).
Research carried out by Schlining (1999) investigates
spot prawn habitat and distribution. Detailed
examination of video transects in, close
to, and outside an ecological reserve in the
Monterey Bay area revealed that spot prawns
are not simply distributed in the most commonly
available habitat type. Although the nature or pattern
of selection is unclear, active habitat selection
seemed to be taking place. Habitat types associated
with spot prawns varied by depth. Spot prawns
were more commonly associated with complex
habitats of mixed sediment and smaller rock types
such as gravel and cobble. The animals were also
associated with large aggregations of drift algae,
where this existed.
Distribution appeared to be very patchy. A finding
that Schlining (1999) correlates with local trap fishers’reports
suggests that spot prawns may be vulnerable
to local overfishing and serial depletion
(Orensanz 1998). The factors determining the size
and location of patches are unclear, but are probably
influenced by spot prawn habitat selection and
larval transport (Lowry, University of Washington
School of Fisheries. Pers. comm., May 2001).
Juvenile spot prawns concentrate in shallow
inshore areas (