Philipp. Scient. 43: 52-68 © 2006, by the University of San Carlos INITIAL STOCK ASSESSMENT OF FOUR STROMBUS SPECIES [MOLLUSCA: GASTROPODA] IN EASTERN SAMAR (CENTRAL PHILIPPINES) WITH NOTES ON THEIR FISHERY Ma. Natalia A. Ciasico, 1 Elaine A. Villaluz, 2 Paul J.L. Geraldino, 3 Danilo T. Dy 3 and Annie G. Diola 3 1 Department of Agricultural Sciences, Eastern Samar State College, 6800 Borongan, Eastern Samar, Philippines Email: natciasico@yahoo.com. 2 Biology Department, Xavier University, 9000 Cagayan de Oro City, Misamis Oriental, Philippines Email: aefore@hotmail.com 3 Marine Biology Section, Biology Department, University of San Carlos, 6000 Cebu City, Philippines Email: dydt_up@yahoo.com ABSTRACT The numerical density, shell length and gonadal con- dition of four Strombus species (S. urceus incisus, S. urceus urceus, S. labiatus, S. gibberulus gibbosus) in three seagrass habitats in Salcedo, Borongan and Quinapondan, Eastern Samar were studied from April 2000 to February 2001. The Salcedo site showed the highest conch density (mean: 77 ind/m 2 ). Among species, S. urceus had the highest density (mean: 51 ind/m 2 ). All four Strombus species have compara- ble shell length ranging from 3 - 5 cm. The Quinapondan site consistently showed the highest mean shell length. Conchs in the three sites generally exhibited varying stages of gonadal development suggesting no definite seasonal cycle but rela- tively more mature individuals were observed during the northeast monsoon (October to January). A small-scale Strombus fishery involving gleaning activities with no imple- ments exists in all sites. Strombus meat is consumed locally, while the shell is sold to the manufacturers of costume jew- elry, shellcraft and furniture exporters in Cebu City, central Philippines. At the time of the investigation, there are no exist- ing government regulations to conserve the conch resources in Eastern Samar.