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vol-33POPULATION, ECOLOGY AND BIOLOGY OF SCOPIMERA
CRABRICAUDA ALCOCK (DECAPODA: BRACHYURA,
OCYPODIDAE) ON A QATAR SAND FLAT
JASSIM A. AL-KHAYAT
Chemical and Earth Sciences Department
Marine Sciences section, College of Arts and Science
University of Qatar, Doha P. O. Box 2713, Qatar
[email protected]
Keywords: Decapoda, Qatar, Arabian gulf, Ecology.
ABSTRACT
The inter-tidal sand flats of Al-Wakrah, Qatar were sampled monthly from October
2004 to September 2005 for the ocypodid crab Scopimera crabricauda Alcock. The study
included a total of 454 individuals (326 males and 128 females). The mean abundance of
this species was high during June-July and decrease from December to January. The CW
measurements revealed that males are heavier than females. The ovigerous females
comprised of 8.3% and 50% in the classes of >3.5 and the males were significantly
outnumbered in most class-size. The Scopimera crabricauda showed two peaks of breeding
March-April and September-October. The major breeding peaks were in April 53.9% and
the lowest in September. The female Scopimera crabricauda attains sexual maturity at 3.8
mm in carapace width. The peak in number of juvenile crabs that recruitment of this species
mainly takes place between October-November and April-June. The sex ratio in the smaller
size classes shows no significant deviation from 1:1, but there was significant deviation in
the higher classes.
