Early Life Cycle Description And Effects Of Microalgal Diets On Larval And Post-Larval Development Of The Mangrove Cockle Anadara Tuberculosa (Sowerby, 1833)

Natural populations of the edible mangrove cockle (Anadara tuberculosa) are threatened by overexploitation and environmental degradation due to anthropogenic activities. The indoor production of larvae and early spat of mangrove cockles requires knowledge regarding the evolutionary characteristics of their larval morphology, associated with the appropriate use of microalgae. Therefore, we describe the larval and early post-larval development of A. tuberculosa raised in the laboratory and the effect of six microalgae on its growth and survival. Additionally, microalgae ingestion-digestion was determined using epifluorescence microscopy, and the fatty acid profile of the microalgae was analysed. Microscopic observations indicated the presence of D veliger larvae 18 h post fertilization, and the first batch of spat was obtained after 45 days of culture. The spat reached a manoeuvrable size at 90 days post fertilization (3 mm). Best shell lengths of oculated larvae (157.62 and 172.47 mu m), daily growth rates (4.77 and 4.52 mu m/day), survivals (30% and 23%) and settlement rates (23% and 11%) were obtained with the diatoms Chaetoceros gracilis and Chaetoceros muelleri respectively. Diets Tetraselmis chuii, Thalassiosira sp. and Pavlova lutheri, despite being ingested-digested, did not result in oculated larvae, which possibly indicates an inadequate lipid content for A. tuberculosa larvae culture. Larvae seem to have a high nutritional requirement for myristic acid, palmitoleic acid, hexadecadienoic acid, stearic acid and eicosapentaenoic acid. Our findings show the feasibility of producing spat in captivity, which contributes to promoting its production and thereby developing ecological restoration plans and/or diversifying aquaculture in Ecuador.