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vol-31POPULATION STRUCTURE AND BIOLOGY OF THE CRAB
DOTILLA SULCATA FROM ELGHARQANA MANGROVE,
SOUTH SINAI, RED SEA
WAFAA S. SALLAM
Department of Marine Science, Suez Canal University, Ismailia, Egypt.
Keywords: Population structure, biology, Dotilla sulcata, mangrove, Red Sea.
ABSTRACT
The population of the crab Dotilla sulacta of Elgharqana mangrove of South Sinai, Red
Sea was studied by monthly sampling during low tide periods from February 2001 to
January 2002. Crabs were collected by digging and seiving. Crabs were sexed, measured
and berried females and moulting stage was recorded. A total of 1619 individual was
obtained, of which 746 (46.1%) were males, 715 non-ovigerous females (44.2%), 106
(6.5%) ovigerous females and 52 (3.2%) juveniles. The overall sex ratio (M:F) was 1:1.1
and females outnumbered males during August-November The population shows sex
differences in the size frequency distributions, with males reaching greater size than
females. (3.5-12.1mm & 3.2-9.4mm carapace width respectively). Ovigerous females were
observed during April-August and ranged in size between 4-9.2mm in carapace width.
Juvenile recruitment to the population was discernible during July. Egg number increased
with female size. Post-moult specimens were encountered during October-December.
Linear models were observed in carapace width and length relationships for both sexes.
