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Big
gulp:
Groupers are the top predators in calm, shallow waters. They hunt
alone, and either creep up on their prey or lie in ambush. They suck
in prey by suddenly opening their huge mouths. Groupers have sharp,
spiky teeth. These merely grip and don’t kill, so the prey is usually
swallowed alive!
Grouper babies: Members of the
Family Serranidae can change their gender! Most are female when they
first reach maturity. As they get larger, some may change into males.
Some groupers gather in large aggregations at a particular place to
spawn. Such aggregation sites are often the part of a reef with strong
currents that wash the fertilised eggs out to sea, to develop away
from hungry filter-feeders.
Human uses: Groupers are edible
and a highly valued seafood dish for many Singaporeans. However, we
may be eating the groupers to extinction.
Status and threats: Groupers are
vulnerable to overfishing because they are not numerous to begin with.
At the same time, they have high commercial value and are relatively
easy to catch. Being top predators, they are naturally uncommon. They
reach maturity and maximum size relatively slowly. Thus overfishing
of young fish before they are able to reproduce can have a serious
effect. Males are larger and rarer, thus more vulnerable to overfishing.
This can result in an imbalance in the gender ratio which can affect
reproduction. Overfishing at the spawning sites of groupers can also
devastate the local population of these fishes. In Southeast Asia,
groupers are widely farmed in floating cages or in ponds and tanks.
However, the farms are mostly stocked by juveniles harvested unsustainably
from the wild. |
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Links
IUCN
Groupers and Wrasses Specialist Group: Details on groupers and the threats
they face.
Groupers
(Serranidae, Epinephelinae): Endangered Apex Predators of Reef Communities
(PDF) by Gene R Huntsman et al Beaufort Laboratory, Southeast Fisheries
Science Center, US National Marine Fisheries Service: Report on the global
threats to groupers due to overfishing.
Conservation
Overview and Action Plan for Australian Threatened and Potentially Threatened
Marine and Estuarine Fishes By J. J. Pogonoski, D. A. Pollard and J.
R. Paxton of Environment Australia: Outline of issues in the conservation
of groupers in Australia.
Family
Serranidae from FishBase: Technical
fact sheet on the family, including fact sheets on individual species.
Guide
to the Coastal Resources of Guam: Vol. 1, The Fishes by Steven S. Amesbury
and Robert F. Myers: Basic scientific details of the Family Serranidae
Marty's
Homepage: Lots of photos and brief snippets on a variety of groupers
from Australia and Thailand.
Orange-spotted
Grouper on Eileen's Fish Species page: a brief fact sheet with photo.
Other references
- Lim, Kelvin K.
P. & Jeffrey K. Y. Low, 1998. A Guide to the Common Marine Fishes
of Singapore. Singapore Science Centre. 163 pp. online
version
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