Taxonomy of Finfish (1+2)

Procedure

Identification of commercially important marine

fishes: Siluriformes

Based on the exercise11. separate the group of Siluriformes or using the following characters .

• Abony shield covering part of dorsal surface of head,

• Adipose fin usually present

• Mouth surrounded by 2, 4, or 6 barbels:

• Swimbladder usually ovate and sack-like,

• Spine like (=spinous) rays present at the front of the dorsal and pectoral fins

 

Group the fishes based on the following character.

 

Ariidae: caudal fin forked

• adipose fin present,

• anal-fin base short, not confluent with caudal fin;

• anterior and posterior nostrils close together;

• no nasal barbel.

Siluridae (fresh water):

• dorsal procurrent rays not extending onto dorsum past posterior extent of analfin;

• caudal fin usually forked or truncated, rarely rounded or pointed;

• dorsal fin without pungent spine.

Clariidae and Heteropneustidae (fresh water):

• dorsal fin without pungent spine, and not confluent with caudal fin.

Plotosidae (fresh water and marine):

• 4 pairs of barbels;

• no adipose fin;

• anal fin and second dorsal fin confluent with caudal fin.

Based on the figures given identify some of the similar species available in your region.

Finally write the classification.