Effects of tank colour on larval survival and development of mud crab Scylla serrata (Forskal)

Hatchery culture of mud crabs has not yet achieved commercial viability despite decades of research efforts. Further research is therefore needed to better understand larval culture requirements of the crab. Based on anecdotal observations, an experiment was carried out to test whether the background colour of the culture vessel affected larval culture success. Newly hatched larvae of Scylla serrata were reared in culture vessels of five colours, i.e., black, dark green, maroon, sky blue and white. Larval survival and development were monitored daily until all of them either moulted to the first crab stage or died. The results showed clear effects of background colour on larval survival. A general tendency of higher larval survival in darker-coloured backgrounds was evident. In particular, overall zoeal survival for larvae reared in black vessels was significantly higher than those reared in white ones. Background colour also appeared to affect larval development. Larvae reared in darker backgrounds generally had shorter development times and more synchronized moulting. A significant delay in zoeal development was observed in larvae reared in white vessels. Dark backgrounds possibly facilitated more efficient feeding, reduced settlement of larvae at the bottom of the vessels as well as minimized stress. This result appears to be the first to demonstrate that background colour can significantly affect larval survival and development of a crustacean species.\u

Avanços da maricultura na primeira década do século XXI: piscicultura e carcinocultura marinha Advances in mariculture on the first decade of the XXI century: marine fish and shrimp culture

A piscicultura marinha é um setor pouco desenvolvido na maricultura brasileira. Por vários anos foi avaliado o potencial de cultivo de algumas espécies como o robalo-peva Centropomus parallelus e o linguado Paralichtys orbignyanus. Entretanto, somente a partir do investimento sobre o bijupirá Rachycentron canadum é que empresas privadas passaram a demonstrar maior interesse na atividade. Além dos sistemas tradicionais de piscicultura, o bijupirá pode ser criado em tanques-rede oceânicos. Esta espécie apresenta crescimento rápido, atingindo entre 4 e 8 kg em um ano de vida, e carne de excelente qualidade. A carcinocultura tem sido questionada por questões ambientais, uso de insumos como farinha e óleo de peixe e disseminação de doenças. A criação de camarões em sistemas sem renovação de água "ZEAH" (Zero Exchange, Aerobic, Heterotrophic Culture Systems) ou cultivo em meio aos Bioflocos (BFT) aplica métodos que minimizam estes problemas, contribuindo para uma maricultura mais saudável.<br>Marine fish culture is still in its infancy in Brazil. For several years the snook Centropomus parallelus and the flounder Paralicithys orbignyanus were considered for aquaculture, but their commercial application has not yet been achieved. However, once technology for culture of cobia Rachycentron canadum became available, several private companies showed interest for marine fish culture. Besides traditional rearing technologes, cobia is suitable for open ocean culture in cages. This species shows fast growth rates, fish can achieve 4 or 8 kg within one year of age and its flesh is highly appreciated. Shrimp farming has been questioned for environmental issues, use of fish oil and fish meal, and spreading diseases. Rearing shrimp in systems without water exchange, know as ZEAH (Zero Exchange Aerobic Heterotrophic Culture systems) or bioflocs applies methods that minimize these problems, contributing for the development of sustainable shrimp farming