RESOURCE PARTITIONING BETWEEN TWO SANDY BOTTOM STARFISH FROM PUERTO QUEQUÉN, ARGENTINA.

BROGGER, M. I.; PENCHASZADEH, P. E.

Banyuls-Sur-Mer

Conferencia; 6th European Conference on Echinoderms; 2001

The diet ofLuidia ludwigi scotti Bell, 1917 and Astropecten brasiliensis Muller and Troschel, 1842 was studied by stomachcontent analysis. Both species have tube-feets without suckers and ao incomplete digestive tract (no rectum or anus). Thosecharacteristics and no stomach eversion results in that food items need to be full ingested and the digestion occur intraorally on thestomach, into {he starfishes. Luidia ludwigi scotti feeds over bivalves, ophiuroids and foraminifeans preferentially. The mostingested bivalve species are Abra uruguayensis, Tellina petitiana and Adrana patagonica. Bivalves were founded on the 83% of thestomachs with content, ophiuroids on the 39% and the foraminifeans on the 26%. Astropecten brasiliensis also feed rnostly'onbivalves, with a frequency of76%, followed by gastropods (52%), forarninifeans (43%), cumaceans (38%)and ophiuroids (4%).Most bivalve species ingested are the same than in Luidia ludwigi scotti. The main difference between this two starfishspecies isthe presence of gastropods and cumaceans in the Astropecten brasiliensis guts. The gastropod species found were Acteocinacandei, Calliostoma coppingeri, Calliostoma militaris, Turbonilla uruguayensis and Terebra gemmulata. Other considerabledistinction is that ophiuroids are definitely more important prey item on the Luidia ludwigi scotti diet than in Astropectenbrasiliensis.