SEASONAL OCCURRENCE, DISTRIBUTION AND ABUNDANCE OF Callinectes LARVAE (DECAPODA, CRUSTACEA, BRACHYURA, PORTUNIDAE) (DE ROCHEBURNE) IN THE AIR- WATER INTERFACE (MICRO-LAYER) OF THE CROSS RIVER ESTUARY, NIGERIA
BASSEY ETIM JOB *
Department of Biological Oceanography, Faculty of Oceanography, University of Calabar, Calabar, Nigeria.
UBONG ENO AKPAN
Department of Marine Science, Akwa Ibom State University, Ikot Akpaden, Akwa Ibom State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Investigations were conducted to determine the seasonal occurrence, distribution and abundance of the larvae of Callinectes larvae in the micro layer (air-water interface) in the Cross River State Estuary, Nigeria from January to December 2015 at Parrot Island. Observations confirmed the presence of the larvae of the crabs in the micro layer in varying numerical and relative abundance from which recruitment into the adult standing stock may occur. larvae consisted mainly of zoeae. The peak of the distribution of the crab larvae were in May and June when 269(13.26%) and 267 (13.17%) of the larvae were collected. The least number of the crab larvae was collected in December with 117 individuals which formed 5.77% of the population of the crab larvae. The larval abundance ranged between 117 – 269 individuals (5.77 – 13.26%) with a mean of 193.0 ± 27.7 individuals (19.03 ± 8.72%). There was significant difference (P< 0.05) in the number of Callinectes larvae collected in relation to months of sampling.
Keywords: Seasonal occurrence, distribution, abundance, Callinectes larvae, air-water interface, parrot island, cross river estuary, Nigeria