Effects of size heterogeneity, feeding/fasting strategy and stocking density modulation on body performance and cannibalism rate of Persian sturgeon (Acipenser persicus) larvae

On the other side, counting disappeared

larvae

leads to conclude

cannibalism

rate increased in staved

larvae

treatments (experiment-B),

in particular

for those in hetero and homo-small distribution. Having aggression was apparently observed by pursuing injured

larvae

in starved treatment of both experiments. To some extend

similarly

, over the rearing of other species, spotted seatrout Cynoscion nebulosus, across hatchery-condition, the aggressive nature was slightly alleviated feeding frequently and stocking

density

played a passive role as much as the other factors (Manley, Rakocinski, Lee, & Blaylock, 2014; Manley at al., 2015). Folkvord. (1990) and Baras (2013),

on the contrary

, confirming

cannibalism

rate would be higher as long as fish

larvae

and a juvenile were starved . Though,

cannibalism

as aggressive

behaviour

can be strengthened, similar to our results, by a large amount of food or/and high stocking

density

(Naumowicz et al., 2017).

This

could be referred to the

Persian

sturgeon

nature that feeding

besides

high

density

can lead to cannibalistic

behaviour

and

thus

, it would not be primarily increased unless fish had

such

interactions for food, space or even having

size

heterogeneity. Cannibals apparently cause dyeing small

larvae

,especially those are in the starved groups. Baras et al. (2003) supported the hypothesis expressing cannibals are more eager small fish in a starved group of Eurasian perch. In our study,

however

, it seems the feeding strategy and

size

sorting in spotted seatrout can alter aggressive

behaviour

more than the stocking

density

(Manley et al., 2015). So, the variation in species could probably play a key role in the

cannibalism

rate. Reduction of stocking

density

along with surging in feeding frequency mitigated the

cannibalism

in Asian seabass (Ribeiro et al., 2015).

This

study provides the information confirming feed/fast strategy should be prioritized in

Persian

sturgeon

larviculture. Admittedly, not to mention, the feeding strategy along with moderation stocking

density

might make an appropriate model for alleviation aggressive

behaviour

in

Persian

sturgeon

larviculture. Knowledge in

size

sorting help hatcheries to have more survivability and growth performance based on food competition or

cannibalism

issue, while both starvation and high stocking can

also

cause

size

distribution more and more., Rearing

Persian

sturgeon

larvae

by feeding in optimum

density

, with

size

homogeneity can apply to have a well-organized larviculture.