it is about the length and weight relationship of fish , growth, length, weight, absolute growth, isometric growth, relative growth, allometric growth,

1. Anatomy & Biology of
Shellfish
Dip Sahoo
TNU2022037100012
B.F.Sc. (1st year 2nd Sem)
Submitted to Dr. Suman Takar
Length and weight Relation of fish

2. Length and weight Relation of
fish

3. introduction
Length of a fish :-
The measurement or extent of a fish
from end to end, the greater of two or the
greatest of three dimensions of an object or fish.
Weight of a fish :-
a body’s relative mass or the quantity of
matter contained by it, giving rise to a downward
force, the heaviness of a substance.

4. Length-weight Relation
Definition:-
Length-weight relationships are some statistical
parameters that have been extensively used to
estimate weight from length because of technical
difficulties & the amount of time required to
record weight in the field.
Importance :-To calculate
• Standing stock biomass
• Condition indices
• Ontogenetic changes
• Fatness & wellbeing of the fish
• Growth pattern
• Shape of the fish
• Health of the habitat

5. Length-weight Relation
• For data calculation :-
Total length (TL) was measured with the help of
vernier calliper (Mitutoyo) nearest to 0.01mm & body
weight was taken with a digital balance nearest to
0.001g.
• Length-weight relationship :-
The length-weight relationship of the fishes was
calculated by linear-regression equation of
log TW=log a + b log TL
A log –log plot was done for all the fishes & outliers
were removed.

6. Length-weight Relation
• Condition Factor & Bayesian approach :-
condition factor was analysed using
fulton’s equation i.e. w*100/L3
Bayesian approach was used to analyses the
shape of the fishes

7. Growth
• Growth is a bio-energetic process & is defined
as a change in its length & weight over a
period of time.
• The two parameters exhibit growth of a fish
are length & weight. The growth in length
indicates long term change, whereas growth in
weight is more subject to variation.
• 1.Absolute growth 2.Releative growth
3.Isometric growth 4.Allometric growth

8. Conclusion
• The length-weight relationship of fish are
affected by a number of factors such as
season, habitat, gonad maturity, sex, diet &
annual differences in environmental
conditions.
• The larger size fishes are efficient food finders
with higher foraging ability, particularly when
they neither are nor involved in nest building,
pre-spawning & spawning activities.

9. Any questions ?

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