The potential of the Caribbean strain Chaetoceros muelleri (CHA-C-04) to be produced and used as diet of two commercially important native scallops (Argopecten nucleus and Nodipecten nodosus) was assessed, using the non-indigenous Chaetoceros calcitrans strain, as a control. Growth and biomass of both diatoms were compared under different culture environments (indoor and outdoor) and culture media (F/2, organic fertilizer triple 15 and humus extract). In addition, their bromatological composition and effect on the physiological condition of the scallops fed with both diatoms were compared. The growth and biomass production of C. muelleri and C. calcitrans were higher under indoor conditions and using the F/2 media. Although the content of proteins, lipids and energy was higher in C. muelleri than in C. calcitrans, its size, organic content, growth and biomass values were not different. Scallops fed with both diatoms strains shows similar values for all of the physiological variables measured, including rates of absorption, oxygen consumption, ammonia excretion and scope for growth. Results suggest that the local strain C. muelleri can be successfully produced and used in the diet of A. nucleus and N. nodosus, but do not offer productive advantages.Se evaluó el potencial de la cepa del Caribe Chaetoceros sp. (CHA-C-04) para ser producida y utilizada como dieta de dos pectínidos nativos de importancia comercial (Argopecten nucleus y Nodipecten nodosus) usando la cepa foránea Chaetoceros calcitrans como control. El crecimiento y la biomasa de ambas diatomeas fue comparado en diferentes ambientes (interior y exterior) y medios de cultivo (F/2, fertilizante orgánico triple 15 y extracto de humus). Además, se comparó su composición bromatológica y efecto sobre la condición fisiológica de los pectínidoThe potential of the Caribbean strain Chaetoceros sp. (CHA-C-04) to be produced and used as diet of two commercially important native scallops (Argopecten nucleus and Nodipecten nodosus) was assessed, using the non-indigenous Chaetoceros calcitrans strain, as a control.  Growth and biomass of both diatoms were compared under different culture environments (indoor and outdoor) and culture media (F/2, organic fertilizer triple 15 and humus extract).  In addition, their bromatological composition and effect on the physiological condition of the scallops fed with both diatoms were compared.  The growth and biomass production of Chaetoceros sp. and C. calcitrans were higher under indoor conditions and using the F/2 media. Although the content of proteins, lipids and energy was higher in Chaetoceros sp. than in C. calcitrans, its size, organic content, growth and biomass values were not different.  Scallops fed with both diatoms strains shows similar values for all of the physiological variables measured, including rates of absorption, oxygen consumption, ammonia excretion and scope for growth. Results suggest that the local strain Chaetoceros sp. can be successfully produced and used in the diet of A. nucleus and N. nodosus, but do not offer productive advantages.s alimentados con ambas diatomeas. El crecimiento y la producción de biomasa de Chaetoceros sp. y C. calcitrans fueron superiores en ambientes cerrados y usando el medio F/2. Aunque el contenido de proteínas, lípidos y energía fue mayor en Chaetoceros sp. que en C. calcitrans, sus valores de tamaño, contenido orgánico, crecimiento y biomasa no fueron diferentes. Los pectínidos alimentados con ambas cepas muestran valores similares para todas las variables fisiológicas medidas, incluyendo las tasas de absorción, consumo de oxígeno, excreción de amonio y crecimiento potencial. Los resultados sugieren que la cepa local Chaetoceros sp. puede ser producida con éxito y utilizada en la dieta de A. nucleus y N. nodosus, pero no ofrece ventajas productivas.