This document discusses various morphometric measurements that can be taken when analyzing fish specimens. It lists 31 specific linear measurements that are commonly used, such as total length, fork length, standard length, head length, pre-dorsal length, and measurements of fins and other body parts. The measurements are useful for identification, comparisons between specimens, and studies of growth and maturity. References are provided for additional resources on fish morphology and measurement techniques.

1. Morphometric measurement
Presented by – Abhishek Giri
M.Sc. (Part – II), SEM – IV
R.K.Talreja College UNR-3
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3. Introduction
• Linear measurement
• Lowe-McConnel(1971) & Grant
& Spain (1975).
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4. Points to consider
1. Total length: Maximum elongation from end
to end. Anterior most to the tip of the tail (0.1
cm), In case of differing length of caudal fin,
the longest is taken.
2. Fork length: Distance from anteriormost part
to the anterior limit of the median notch or
the bifurcation of the caudal fin.
3. Standard length: measurement from the tip
of the snout or premaxilla to the base of the
caudal fin (hypural joint), where a groove
forms.
4. Head length: Distance between the snout or
premaxilla & the posterior most edge of the
opercular bone.
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5. 5. Pre-dorsal length: Distance from anteriormost
part of the body to the first dorsal fin ray.
6. Pre-orbital or snout length: Distance from the
anteriormost part of the body to the front
margin of the orbit.
7. Post-orbital length: Distance from the posterior
margin of the orbit to the end of the two
orbitals.
8. Inter orbital width: from the upper margin of the
right orbit to the upper margin of the left orbit
as measured from the dorsal surface. This
measurement is also called as the least
distance between the two orbitals.
9. Eye diameter: Distance between the anterior &
posterior rims of the eye in the longitudinal
axis.
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6. 10. Upper jaw length: from the anteriormost post
of the premaxillary to posterior point of the
maxillary.
11. Lower jaw length: Distance between the two
end point along the margin of the lower jaw.
12. Anal length: Distance from the anteriormost
part to the anterior limit of the anal aperture.
13. Girth length: circumference of the body at its
deepest point. This measurement sometimes
indicates maturity of the species particularly in
females fishes.
14. Body depth: It is the deepest between the
dorsal & ventral surface at the deepest point.
15. Head depth: Perpendicular distance from the
nape to the ventral side of the head.
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7. 16. Gape width: Also termed as width of mouth. It
is the distance between the angles of the
closed mouth.
17. Dorsal fin height: Length of the largest fin ray
or spine of the dorsal fin.
18. Dorsal fin base: Distance between the anterior
& posterior end of dorsal fin taken along the
base of the fin.
19. Pectoral fin length: length of the ray from the
dorsal base of the pectoral fin.
20. Pectoral fin base: Distance between the dorsal
& ventral insertion of the anal fin.
21. Anal fin length: Length of the longest ray from
the anterior insertion of the anal fin.
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8. 22. Anal fin base: Distacne between the anterior &
posterior insertion of the anal fin.
23. Ventral fin length: Length of longest ray from
the anterior insertion of the ventral fins.
24. Ventral fin base: Distacne between the outer
side bases of the ventral fins.
25. Depth of mouth: Distacne between the dorsal
& ventral surface of the head, perpendicularly
through th posterior angle og th emouth.
26. Depth at eye: Distacne between the dorsal &
the ventral surfaces of the head,
perpendicularly through the eye.
27. Depth at dorsal fin: depth of the body,
perpendicularly trough the anterior insertion of
the caudal fin.
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9. 28. Depth at pectoral fins: Depth of the body,
perpendicularly through the base of the
pectoral fin.
29. Depth at anus: Depth of the body,
perpendiculalrly through the anus.
30. Caudal fin height: Distacne between the
stretched lobes of the caudal fin.
31. Length of the peduncle: Distance from the end
of the anal fin the base of the median caudal
rays.
32. Least height of the caudal peduncle: Also
termed as least height of the body. Shortest
height of the caudal peduncle between the end
of the anal fin & origin of the caudal fin
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11. References
• S.P. Biswas, Manual of methods in fish
biology, South Asian publishers private
Ltd., New Delhi.
• courses.washington.edu/fish311/Lab1
7.pdf
• cfcc.edu/faculty/rogers/courses/msc27
6/Meristics%20laboratory.doc
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