Abstract: The goal of this study was to demonstrate the feasibility of culturing the seahorse Hippocampus reidi in an organic integrated multi-trophic aquaculture farm that produces the oyster Crassostrea brasiliana and the shrimp Litopenaeus vannamei. Experiments were conducted to evaluate the effects stocking density and food (natural zooplankton, Artemia nauplii, or both) for the juvenile I, which are fish from 1 to 15 days after birth. Stocking density effect was studied on growth and survival of juveniles II from 30 days to commercial size in net cages. Survival of the juvenile I was not affected by stocking densities from 2 to 5 ind L-1 and was greater than 70% in all treatments. Seahorse length, however, was inversely related to stocking density. Both treatments with wild zooplankton promoted higher seahorse survival and growth than diet composed exclusively by Artemia sp. during the first 15 days of life. Juvenile II growth decreased with stocking density from 5 to 40 ind m-3 but survival was not affected by it. The total benefit and proportion of colored animals increased significantly with stocking density. The present study confirms the technical feasibility of organic multi-trophic seahorse production in net cages. Even at the highest density tested the seahorses grew well and could generate high profits.

Resumen: El objetivo del estudio fue demostrar la viabilidad del cultivo del caballito de mar Hippocampus reidi, en un sistema orgánico de acuicultura multitrófica integrada, compuesta por cultivos de ostra Crassostrea brasiliana y camarón Litopenaeus vannamei. Se realizaron experimentos para evaluar los efectos de la densidad poblacional y la dieta (zooplancton natural, nauplii de Artemia sp., o ambos), en juveniles I, que corresponde de 1 a 15 días después del nacimiento. Se estudió el efecto de la densidad poblacional en el crecimiento y la supervivencia de juveniles II a partir de 30 días hasta el tamaño comercial en jaulas de malla. La supervivencia de la etapa juvenil I no fue afectada por densidades poblacional de 2 a 5 peces L-1 y fue mayor al 70% en todos los tratamientos. El tamaño de los caballitos de mar, sin embargo, estuvo inversamente relacionado con la densidad poblacional. Ambos tratamientos, con zooplancton silvestre, promovieron una mayor supervivencia y crecimiento del caballito de mar que la dieta solo compuesta de Artemia, esto durante los primeros 15 días de vida. El crecimiento de juvenil II disminuyó con la densidad poblacional de 5 a 40 peces m-3 y la supervivencia no fue afectada. El beneficio total y la proporción de animales coloridos aumentaron significativamente con la densidad poblacional. Se confirma la viabilidad técnica de la producción de caballitos de mar multitróficos orgánicos en jaulas de malla, incluso en la densidad más alta probada en este estudio los caballitos de mar crecieron normalmente, lo que podría generar buenos rendimientos económicos.

Daptonema oxycerca foi descrita originalmente para o Mar do Norte, mas até o momento nada se conhece sobre essa espécie em regiões tropicais. A distribuição espaço-temporal e a estrutura populacional de D. oxycerca foram estudadas durante o período de um ano (de Maio 1998 a Abril 1999) em Coroa Grande, Rio de Janeiro, Brasil. Para a amostragem, dois transectos fixos e perpendiculares à linha d'água foram estabelecidos, e, em cada transecto, quatro níveis foram marcados para representar as zonas superior e inferior do médiolitoral. As menores temperaturas foram observadas no final do inverno e início da primavera e as maiores temperaturas no verão. A densidade de D. oxycerca variou durante o ano, com um pico em agosto. Essa tendência foi observada para os machos, as fêmeas grávidas e as fêmeas não-grávidas. A densidade da espécie correlacionou-se negativamente com a temperatura. A variação da razão sexual não foi significativa. D. oxycerca foi mais abundante no nível superior do médiolitoral em ambos os transectos. Esse trabalho representa o primeiro registro de D. oxycerca no Brasil, assim como, confirma a influência da temperatura na regulação de sua densidade populacional.

Daptonema oxycerca was originally described from the North Sea and, up to now, nothing is known of this species in tropical regions. The spatio-temporal distribution and the population structure of this species was studied during one-year period (from May 1998 through April 1999) in Coroa Grande, Rio de Janeiro, Brazil. For sampling, two fixed, parallel transects were established perpendicularly to the shoreline, and at each transect, four, equally spaced levels were marked to represent the upper and the low intertidal zones. The lowest temperatures occurred in the end of the austral winter and first month of the spring and the highest temperatures occurred in the austral summer. The density of D. oxycerca varied during the year, with a peak in August. This tendency was observed for males, ovigerous females, and non-ovigerous females. The species density was negative correlated with temperature. The sex ratio was not statistically significant. D. oxycerca was most abundant at the upper intertidal level in both transects. This work provides the first record of D. oxycerca in Brazil, and confirms the influence of temperature in regulating its population density.