Species identification and population parameter of fiddler crabs, Uca spp. in Olango Island Wildlife Sanctuary, Cebu

Date of Publication


Document Type

Master's Thesis

Degree Name

Master of Science in Biology


College of Science



Thesis Adviser

Ma. Carmen Ablan Lagman

Defense Panel Chair

Maria Rowena R. Eguia

Defense Panel Member

Divina M. Amalin
Marivene M. Santos
Glenn V. Alea


This study is a first report to identify and characterize the fiddler crabs, Uca spp. found in the Olango Island Wildlife Sanctuary (OIWS), Cebu, a wetland of international importance for migratory birds. Uca spp. are major contributors to the biomass that feeds local and migratory birds in this sanctuary. A total of 426 crabs were collected from four sites in a 0.09 km2 area of the sanctuary. Morphological characters, CO1 mtDNA and 16S rDNA sequences, and population parameters were used for species identification. Phylogenetic analyses were performed to understand ancestral relationship among species. Species relative abundance in relation to pH, salinity and temperature were studied.

Five species Uca annulipes, Uca crassipes, Uca perplexa, Uca tetragonon, and Uca jocelynae were clearly identified in the sanctuary. High species richness were observed in OIWS compared to other areas in the region. Morphological, molecular, and population parameters showed subgenera clustering which indicate that the most recent taxonomic classification applies to the OIWSs Uca species. Morphometric characters and population parameters showed overlaps in species differentiation which may be due to reproductive stage behavior and exposure to predation. There were no significant differences among the mean pH, salinity, and temperature among the four sites. However, not all species were found in all sites. Substrate type and habitat preference may be explored as other ecological parameters that may affect species composition apart from pH, salinity, and temperature given the scale of the study.

Abstract Format






Accession Number


Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

1 computer disc ; 4 3/4 in.


Fiddler crabs; Wildlife conservation; Wildlife management

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