Population density, size distribution, and morphology of Nerita undata Linn. in the rocky shores of Wala Bagalangit, Mabini, Batangas, Luzon island and off Layaglayag, Caban island, Tingloy, Batangas during the summer and rainy seasons of 1998

• Main Authors: Gapasin, Glacie lD, Ramos, Patricia Marcos, Torres, Marie Joan Paraiso
• Format: text
• Language: English
• Published: Animo Repository 1999
• Subjects: Sea snails; Neritidae, Fossil; Population density > Philippines > Batangas; Biology
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/11281
• Institution: De La Salle University

Population density, size distribution, and morphology of the neritids in the rocky shores of Wala, Bagalangit, Mabini and Layaglayag, Caban Island, Tingloy in Batangas were compared. Differences and similarities in these parameters of the neritids during the summer and rainy seasons were also studied. To determine the population density a 100-m transect line was laid down parallel to the shore in the high intertidal zone where the neritids are usually found. The samples were then collected and counted. For the size distribution and morphology, the neritids height and length were measured using a caliper. The collection of the samples was done twice, in May and September of 1998. This was done during daytime at low tide. The results showed that the neritids were more abundant during the summer and rainy seasons in Wala as compared to Layaglayag. The results of the t-test showed that there is a significant difference between the population density in Wala and Layaglayag. This was also true for the summer and rainy seasons. Their lengths reveal that most of them are of the same length. This is in Wala and Layaglayag. On the other hand, their heights are relatively different. Height of neritids in Wala is much smaller as compared to that of the height of neritids in Layaglayag. This is because intraspecific competition in Wala is greater than that of in Layaglayag. The results of the t-test showed that length and height of neritids in Wala were significantly different from the height and length of the neritids in Layaglayag. On the other hand, length and height of the neritids during the summer were not significantly different from the length and height during the rainy season. The type of habitat of neritids affects its morphology specifically the shell shape. The results of the test for slopes showed that the slopes between length and height in Wala and Layaglayag were not significantly different. This was also true for the summer and rainy seasons.