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Journal of Marine Biology
Volume 2010 (2010), Article ID 201932, 10 pages
http://dx.doi.org/10.1155/2010/201932
Research Article

Feeding Choice and the Fate of Organic Materials Consumed by Sesarma Crabs Perisesarma bidens (De Haan) When Offered Different Diets

1The First Vice President's Office, Department of Environment, P.O. Box 2808, Zanzibar, Tanzania
2School of Education, Arts and Science, State University of Zanzibar, P.O. Box 147, Zanzibar, Tanzania
3Laboratory of Ecology and Systematics, Faculty of Science, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa 903-0213, Japan

Received 29 October 2010; Accepted 30 December 2010

Academic Editor: Pei-Yuan Qian

Copyright © 2010 Islam S. S. Mchenga and Makoto Tsuchiya. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The feeding preference of the sesarmid crab Perisesarma bidens was investigated when offered different diets: Enteromorpha intestinalis (algae), Kandelia obovata leaves, and propagules. Nutritional value of food, its assimilation, and fates were evaluated using a combination approach of the fatty acids (FAs) and C/N ratios. When offered a mixed diet, male crabs preferred algae than leaves and/or propagules, while a female preference was equally for leaves and algae but less than propagules. The nutritional value of algae was higher as indicated by low C : N ratios and high ratios than leaves and propagules. FAs comparison of tissues and faeces indicated that crabs efficiently assimilate essential fatty acids (EFAs) from a given diet in the order of algae greater than leaves and propagules. Despite of sesarmid crabs being a mangrove leaf-eater, E. intestinalis can potentially be important source of nitrogen supplement for P. bidens under mangrove forests.