Taxonomy of Finfish (1+2)

Procedure

· Collect fish specimen from the commercial landing centre, fish market or collect them using fish net from the natural water bodies.

· Bring them to the laboratory.

· Wash them with fresh water to remove the dirt, sand particles and mucus.

· Measure various linear lengths. (for total length, standard length, fork length, pre-dorsal length, post dorsal length, dorsal fin base , length of longest fin ray, inter dorsal fin space, length of pelvic fin, length of caudal peduncle, depth of caudal peduncle, body depth, head depth or height of head at occipital, head width, eye diameter, interorbital width, pre orbital length, post orbital length , pre anal length, post anal length, snout length, length of the pectoral fin and width of gape of the mouth)

• convert into percentage of total length.

· Compare the character among them.

· Draw a neat diagram.

· Record your observation.

• Repeat the same for some more fishes and tabulate your observation.
• Calculate range, mean, standard deviation and standard error and tabulate your result as given in the following tables.

Note: Length measurements are usually made with the fish lying on its right side snout to the left, on a measuring consisting a essentially of a wooden or a metal base, carrying a scale and having a head piece against with the snout is to be placed.

The mouth of the fish should be closed, the fish body and the tails are straightened along the midline and the readings are to be recorded from the scale. All the measurement should be taken in percent of standard length or fork length or standard length.

For computation the factor should be found out by dividing 100 with standard or fork length.

Then this factor is multiply with each morphometric character for a single specimen to get percentage of total length. The same procedure has to be made for all the specimen of the species that are studied. From this, the range, mean, standard error has to be calculated.

WORK SHEET

1.Morphometric measurement of fish

Name of the species: ………………………………….

Locality : …………………………………..

Depth : …………………………………..

#	Morphometric Measurements	Length (cm)	In % of Total Length
1	Total Length
2	Fork Length
3	Snout Length
4	Head Length
5	Interorbital Width
6	Depth D1-D2
7	Depth D2-A2
8	Upper jaw length
9	Base D2 fin
10	Dorsal fin Length
12	Base A2 fin
13	Anal fin Length
14	Pelvic fin Length
15	Pectoral fin length
16	Straight lateral line Length
17	Curved lateral line Length
18	Length from Snout to D1 fin
19	Length from Snout to D2 fin
20	Length from Snout to pelvic fin
21	Length from Snout to pectoral fin
22	Length from Snout to A2 fin
23	Depth of Caudal Peduncle

2. Body Proportions of Fish in % of Standard Length

Name of the species: ………………………………….

#	Parameters	Range of ratio	Mean ratio	Standard deviation	Standard error
1	Total Length
2	Fork Length
3	Snout Length
4	Head Length
5	Interorbital Width
6	Depth D1-D2
7	Depth D2-A2
8	Upper jaw length
9	Base D2 fin
10	Dorsal fin Length
12	Base A2 fin
13	Anal fin Length
14	Pelvic fin Length
15	Pectoral fin length
16	Straight lateral line Length
17	Curved lateral line Length
18	Length from Snout to D1 fin
19	Length from Snout to D2 fin
20	Length from Snout to pelvic fin
21	Length from Snout to pectoral fin
22	Length from Snout to A2 fin
23	Depth of Caudal Peduncle

3. Comparison of Morphometric Characters of Species _____________________________ and _______________________________

#	Parameters	Range of overlapping ratio	Overlapping ratio	Range of extreme ratio	Extreme ratio	% of overlapping
1	Total Length
2	Fork Length
3	Snout Length
4	Head Length
5	Interorbital Width
6	Depth D1-A1
7	Depth D2-A2
8	Upper jaw length
9	Base D2 fin
10	Dorsal fin Height
12	Base A2 fin
13	Anal fin Height
14	Pelvic fin Length
15	Pectoral fin length
16	Straight lateral line Length
17	Curved lateral line Length
18	Length from Snout to D1 fin
19	Length from Snout to D2 fin
20	Length from Snout to pelvic fin
21	Length from Snout to pectoral fin
22	Length from Snout to A2 fin
23	Depth of Caudal Peduncle