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Fish Identification Points

Ever wondered how the thousands of fish types are identified and differentiated from each other? Here’s how it isdone. To identify species of fish, following tools are used:

Meristic - Counts

Morphometric - Measurements relative to length

Anatomical traits - shape, presence/absence

Colour patterns

We'll discuss the first two thoroughly as the other two are very simple and easy to understand. So, lets move on...

Meristic: (Counting)

1. Scale counts:

Lateral line scale count

Scales above lateral line

Scales below lateral line

Scales before dorsal fin

2. Fin (Ray and Spines) count:

Spines: Single‐shafted, entire composition, designated by roman numerals.Soft rays: Bilaterally paired, segmented, branched, flexible, designated by Arabic numerals. Fin formulae: Counting of each fin (number of Spines and Rays)

A fin may contain them both.Example: D XIII 12, A III 15, P 6, V I 6, C 9 (D dorsal, A – anal, P – pectoral, v – ventral or pelvic, C –caudal).

Morphometric: (Measurement)

Standard length (From snout to base of caudal fin)

Head length (Snout to Operculum)

Snout length (Distance between eye orbit and mouthtip)

Dorsal Fin Length

Pelvic fin length

Pectoral fin length

Caudal fin length

Anal fin length

Eye orbit Length

Upper jaw length

Body depth

Pointed dividers or dial‐reading callipers are used for these measurements. Measurements are recorded in % ofStandard length.

Procedure

1. Take sample fish, Take more than one fish as sample.

2. Collect Required Standard data bout fish in published form.

3. Take observation of Morphometric and meristic.

4. Tele your observations with standard readings.