Meeting Abstract

48.4  Tuesday, Jan. 5  The effects of the association with eelgrass on the embryonic development of the gastropod Haminoea vesicula (Gould, 1855) FERNANDES, D.A.O.*; PODOLSKY, R.D.; Grice Marine Laboratory, College of Charleston, SC; Grice Marine Laboratory, College of Charleston, SC dafernan@edisto.cofc.edu

Marine gastropods commonly deposit egg masses in association with photosynthetic organisms. The gastropod Haminoea vesicula attaches its egg ribbons to the eelgrass Zostera marina. Photosynthesis by such macrophyte can provide significant amounts of oxygen to embryos throughout the egg ribbon. Little is known, however, about the actual benefits or costs to embryonic development of this intimate association. I examined the effects of the association between H. vesicula egg ribbons and the eelgrass Z. marina on developmental rate and larval shell length. Pieces of Haminoea vesicula egg ribbon were pinned into mesh-bottom plastic trays. Half of the egg mass pieces were pinned onto Z. marina blades. Embryos were placed in outdoor tanks with flowing seawater and raised under five different light conditions: 0%, 25%, 50%, 75% and 100% blocked sunlight. Embryos attached to eelgrass developed significantly faster under good light conditions, whereas, under poor light conditions, the association with Z. marina significantly increased development time. Under moderate light levels (25% – 50% blocked sunlight), development of H. vesicula was faster whether embryos were attached or not to the macrophyte. A significant decline in newly-hatched larvae shell length was observed at low light levels. The association with eelgrass did not affect larval hatching size.