Abstract:
Analysis of the digestive contents of four aspidochirotid holothurians species (Holothuria poli, H. tubulosa, H.
forskali and H. sanctori) sampled in two localities in the Mostaganem area (Stidia, Salamandre) were carried
out in order to overview the different food sources appreciated by these animals.
Our results show that holothurians feeds on diatoms, cyanophytes, macrophytes algae, Posidonia oceanica
leaves (alive and dead), foraminifera, crustaceans, molluscs bivalve shells, sponge ossicles and nematodes.
Diatoms were mostly consumed by holothurians at both sites. The greatest rates of ingested diatoms are
recorded for H. poli (38.66% and 34.44% respectively at Stidia and Salamandre). The Posidonia oceanica leaves
(alive and dead) are also consumed, but with low rates. Holothuria forskali feeds in a preferential way on the
Posidonia oceanica leaves (3.33% dead leaves, 14% live leaves at Stidia and 9% live leaves at Salamandre).
Foraminifera are consumed mostly by H. forskali (13.33% and 15% respectively at Stidia and Salamandre),
even if that food source is not appreciated very much (Ivlev index: -0.3 and -0.06 respectively at Stidia and
Salamandre). At both sites, most holothurian species consume large amounts of sponge ossicles and this
is their preference. Crustaceans and nematodes are less consumed, regardless of their significant electivity
index (Ivlev index = 1 for nematodes, in most holothurians species of Stidia area).
