Gut analysis of Sardinella tawilis (Herre) from Taal Lake, Philippines: algal species composition and microcystin occurrence

Date

3-2006

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Macrina T. Zafaralla

Abstract

A study was done on Sardinella tiawilis (Herre) caught in Taal Lake to determine the algal components of the fish's food intake. Species composition was determined in fish caught in five different months of the years. Twenty species of algae were identified representing the Cyanophyceae, Chlorophyceae, Bacillariophyceae and Dinophyceae. The Cyanophyceae had the greatest number of representatives followed by the Chlorophyceae, Bacillariophyceae and Dinophyceae, in that order. Moreover, ten of these 20 algal species are new records to the list of Tamayo-Zafaralla (1998) and Zafaralla and Orozco (1989). The microcystin-producing Microcyslis aeruginosa was most plentiful in December thus, the analysis of cyanotoxins was carried out in fish caught during this month. The cyanotoxins MC-LR and MC-RR were detected in the fish gut. MC-LR was most concentrated in the esophagus (950 μg/kg tissue) followed by the stomach (51.5 μg/kg tissue). None was detected in the intestines. The MC-RR analog was found in the intestine only (3.5 μg/kg tissue). Algal density and richness in the number of BGA representatives did not seem to relate directly with MC-LR in the gut sections, but MC-RR seem to relate directly. There was an indication that MC-LR was concentrated in the esophagus where the freshness of the BOA cells may have affected the concentration of toxin measured. None of the microcystins was detected in the liver. More studies are recommended to validate the present findings particularly with respect to toxin concentration since the fish samples examined were more than two months old.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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