Taxonomy of Finfish

2.4.1 Preservation

The finfishes collected from landing centre or from fish pond or from fish market should be preserved in formalin.  Commercial formalin is concentrated (about 40%) and so must be diluted to 8-10%.  When finfishes are collected from landing centres, colour patterns, blotches, spots, stripes and other morphological characters are to be noted carefully (in fresh condition) in the field note book.  Preserved fishes should be packed in plastic jars/bottles with the tail pointing upwards to avoid damage to the caudal fin.  The bottles should be neatly labelled.  Labels should indicate serial number, exact locality, date and time of collection, gear and craft employed, depth of the water and sexual dimorphism if any are to be noted.  In addition to this, the local names should be written on the label.  The specimens thus collected from the landing centre has to be preserved as mentioned above.  The label also should include scientifc name, popular name, sex and name of the collector.  Specimens less than 10 cm (TL) can be preserved directly in 8% formalin solution.  Ten percent concentration will suit for most of the fishes. For specimens measuring 10-30 cm TL, a slit should be made along the belly, preferably to the right side of the midline of the body without injuring the alimentary canal.  The preservative i.e., formalin should be allowed to enter through this slit.  Before preservation, entire fish and all the fins of  the fish have to be stretched in a measuring board and should be preserved.