水産養殖研究開発ジャーナル

概要

Abundance and Distribution of Freshwater Eels in Pangi River, Maitum, Sarangani Province

Valdez ASM ,Castillo TR

A study on the abundance and distribution of Freshwater Eels was conducted in Pangi River, Maitum Sarangani Province. Three stations, 50 meters away from each other, were set starting at the mouth of the river with coordinates 06.02278° N, 124.52069°. In every station are three substations at the right side near the bank, at the center and at the left side near the bank. The study was done from a period of 5 months starting from October 2014 to February 2015. Sampling was done every Full moon and New moon of the month during the low tide and high tide fluctuation. Salinity and temperature were also monitored during sampling.

The freshwater eels were identified using morphological characteristics. A total of 4,262 individuals had been collected for five (5) months of sampling, Freshwater eels were found abundant during new moon with a total of 4,249 individuals and only 13 individuals were collected during full moon.

Results showed that two species of Freshwater eels has been observed on the area out of 18 species of Freshwater Eels, the Anguilla marmorata and the Aguilla bicolor pacifica. The study further showed that the Anguilla marmorata is most abundant with abundance index of 96.62%, frequency index of 100% and dominance index of 196.62%, while Anguilla bicolor pacifica had the abundance index of 3.26%, frequency index of 42.86% and dominance index of 46.12%.

There are two types of bottom substrates observed in the area Station 1 had sandy while Station 2 and 3 had rocky substrate. Anguilla marmorata is more often seen in the rocky bottom since they prefer to hide under the rocks and gravely bottom.

Catch per unit effort (CPUE) was computed to range from 0.075gm/hour to 500 gm/hour. Temperature was monitored to be within the range of 23°C-25°C for the entire sampling period.

Further study is recommended to monitor the freshwater eels that migrating upstream the river of Pangi, Maitum, Sarangani Province, beyond Station 3.