Biology of Finfish and Shellfish

Procedure

Specimen of frigate tuna, sardine, marine cat fish, barracuda, grouper, horse mackerel and shark collected from the local fish landing centre and brought to the biology laboratory. In the laboratory, the specimens should be washed in running water to remove dirt and mucus, and then dried with the help of cotton. Food and feeding habits can be determined by studying mouth opening, teeth, gill rakers, oesophagus, stomach, intestine, pyloric cecae and rectum. On the basis of food taken, fishes are grouped as herbivores, carnivores, omnivores and plankton feeder.

The specimens may be dissected ventrally with the help of scissors superficially to avoid damaging the visceral organs. Now the different organs of digestive system could be examined.