Investigation du cycle de vie larvaire de la crevette symbiotique Synalpheus stimpsonii; cas du Sud-Ouest de Madagascar

Abstract

Synalpheus stimpsonii is a pistol shrimp of Alpheidae’s family and measures between 03
and 04 cm with two asymetrical claws of which one is hypertrophied. It is found at about
30 m depth and lives in symbiosis with crinoids such as Phanogenia distincta. The collect
was made from 08 April 2022 to 23 April 2022. The gravid females had green eggs and
sizes 1,08 ± 0,09 (mm). The eggs of 09 gravid shrimp were incubates at a temperature
ranging from 27,81°C descreasing to 23,73°C, stable salinity at 35,34‰, pH 8,46 mg/L and
variable incubation time related to the developmental stage of the eggs. The average rate of
hatching is 47,81 ± 8,98%. The larvae from hatching live only 04 days at a temperature
condition between 27,38°C and 23,03°C and salinity 35,19‰ with a daily decrease in
number and may not yet be attracted to host organisms. And according to the experiments
on larvae; there is a stationned growth (average size is 4,95 ± 0,008 mm) despite of various
diets administration (phytoplancton and Artemia nauplii) and no metamorphosis observed:
at that step, larvae are lecithotrophy and pelagic. This study must be deepened.