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Evaluating different densities of polychaetes in integrated multi-trophic aquaculture system (IMTA) combining sea urchin Paracentrotus lividus (Lamarck, 1816) and polychaete Hediste diversicolor (O.F. Müller, 1776)
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Com o crescimento exponencial da população, o sector da aquicultura tem crescido rapidamente nos últimos anos. O desenvolvimento de novas abordagens, tecnologias, sistemas de cultivo e práticas responsáveis e sustentáveis são necessárias para apoiar o crescimento esperado da aquacultura. Uma dessas abordagens sustentáveis é a Aquicultura Multitrófica Integrada (AIMT), que envolve a incorporação de espécies de diferentes níveis tróficos ou nutricionais no mesmo sistema. Nestes sistemas, é crucial selecionar as espécies adequadas de modo a obter um processo biológico e químico otimizado que melhore a qualidade do ecossistema e a sustentabilidade da indústria. Tanto o anelídeo poliqueta Hediste diversicolor como o ouriço-do-mar Paracentrotus lividus são espécies importantes e bem conhecidas na aquacultura. As gónadas de ouriço-do-mar são uma iguaria muito apreciada em todo o mundo, sendo o P. lividus a espécie de ouriço-do-mar mais consumido na Europa e um alvo desejável para a aquacultura. O poliqueta H. diversicolor tem uma grande tolerância fisiológica a fatores ambientais extremos, o que o torna uma espécie adequada para um sistema IMTA. Além disso, tem um elevado valor económico como isco de pesca e como fonte de alimento para outras espécies produzidas em aquacultura. O objetivo deste estudo foi avaliar, pela primeira vez, a viabilidade de um sistema integrado de aquacultura multitrófica à escala laboratorial, combinando P. lividus e H. diversicolor numa experiência de dois meses. Neste estudo, foram testadas três densidades de poliquetas, 150, 300 e 450 ind/m2. Ambas as espécies foram mantidas em três sistemas RAS (sistema de recirculação aquícola), cada um composto por três tanques. Os ouriços-do-mar foram mantidos em cestos flutuantes em cada tanque, enquanto os poliquetas foram mantidos por baixo, numa camada de 5 cm de sedimento. No final da experiência foram avaliados o crescimento somático e o crescimento gonadal do P. lividus, bem como a sua sobrevivência. Foram ainda avaliados os efeitos da densidade de poliquetas H. diversicolor sobre a sua sobrevivência, crescimento e maturação. Os ouriços-do-mar apresentaram uma taxa de crescimento somático ligeiramente superior quando a densidade de poliquetas foi 300 ind/m2, com um aumento de peso de 0,48 ± 0,41 g e de comprimento de 1,35 ± 0,50 mm. Em termos de crescimento gonadal, o índice gonadossomático foi semelhante entre as três densidades testadas, com um aumento médio de 3%. O H. diversicolor apresentou uma taxa de crescimento positiva em todas as densidades testadas, com um ganho de peso variando entre 0,19 ± 0,024 g e 0,16 ± 0,010 g, enquanto os valores da taxa de crescimento específico variaram entre 3,05 ± 0,16 %/dia e 2,78 ± 0,098 %/dia. De um modo geral, este estudo demonstrou que os juvenis de H. diversicolor podem ser produzidos com sucesso em sistemas integrados com ouriços-do-mar P. lividus, tendo como única fonte de alimento os seus resíduos.
The aquaculture sector has grown rapidly in recent years due to the exponential growth of the world's population. The development of new approaches, technologies, farming systems and responsible and sustainable practices is needed to support the expected growth of aquaculture. One such sustainable approach is Integrated Multi-Trophic Aquaculture (IMTA), which involves the incorporation of species from differing trophic or nutritional levels within the same system. In these systems, it is crucial to select the right species to achieve an optimised biological and chemical process that improves the quality of the ecosystem and the sustainability of the industry. Both the polychaete annelid Hediste diversicolor and the sea urchin Paracentrotus lividus are important and well-known species in aquaculture. Notably, sea urchin gonads are an esteemed delicacy worldwide, while P. lividus is the most consumed sea urchin in Europe and a desirable target for aquaculture. H. diversicolor has a physiological tolerance to extreme environmental factors, making it a suitable species for an IMTA system. Additionally, it holds considerable economic value as fishing bait and as a food source for other species produced in aquaculture. The aim of this study was to assess, for the first time, the viability of an integrated multi-trophic aquaculture system on a laboratory scale by combining P. lividus and H. diversicolor in a two-month trial. Three different densities of polychaetes (150, 300 and 450 ind/m2) were tested in this study. Both species were kept in three RAS (recirculating aquaculture system) systems, each comprising three tanks. The sea urchins were held in floating baskets in each tank, while the polychaetes were kept in a 5 cm layer of sediment beneath. At the end of the experiment, somatic and gonadal growth of P. lividus and their survival were assessed. The effect of density of H. diversicolor polychaetes on their survival, growth and maturation was also assessed. The sea urchins showed a slightly higher somatic growth rate at a polychaete density of 300 ind/m2, with an increase in weight of 0.48 ± 0.41 g and in length of 1.35 ± 0.50 mm. In terms of gonadal growth, the gonadosomatic index was similar between the three densities tested, with an average increase of 3%. H. diversicolor showed a positive growth rate at all densities tested, with weight gains ranging from 0.19 ± 0.024 g to 0.16 ± 0.010 g, while specific growth rate values ranged from 3.05 ± 0.16 %/day to 2.78 ± 0.098 %/day. Overall, this study has shown that juvenile H. diversicolor can be successfully reared using the sea urchin P. lividus wastes as the sole food source.
The aquaculture sector has grown rapidly in recent years due to the exponential growth of the world's population. The development of new approaches, technologies, farming systems and responsible and sustainable practices is needed to support the expected growth of aquaculture. One such sustainable approach is Integrated Multi-Trophic Aquaculture (IMTA), which involves the incorporation of species from differing trophic or nutritional levels within the same system. In these systems, it is crucial to select the right species to achieve an optimised biological and chemical process that improves the quality of the ecosystem and the sustainability of the industry. Both the polychaete annelid Hediste diversicolor and the sea urchin Paracentrotus lividus are important and well-known species in aquaculture. Notably, sea urchin gonads are an esteemed delicacy worldwide, while P. lividus is the most consumed sea urchin in Europe and a desirable target for aquaculture. H. diversicolor has a physiological tolerance to extreme environmental factors, making it a suitable species for an IMTA system. Additionally, it holds considerable economic value as fishing bait and as a food source for other species produced in aquaculture. The aim of this study was to assess, for the first time, the viability of an integrated multi-trophic aquaculture system on a laboratory scale by combining P. lividus and H. diversicolor in a two-month trial. Three different densities of polychaetes (150, 300 and 450 ind/m2) were tested in this study. Both species were kept in three RAS (recirculating aquaculture system) systems, each comprising three tanks. The sea urchins were held in floating baskets in each tank, while the polychaetes were kept in a 5 cm layer of sediment beneath. At the end of the experiment, somatic and gonadal growth of P. lividus and their survival were assessed. The effect of density of H. diversicolor polychaetes on their survival, growth and maturation was also assessed. The sea urchins showed a slightly higher somatic growth rate at a polychaete density of 300 ind/m2, with an increase in weight of 0.48 ± 0.41 g and in length of 1.35 ± 0.50 mm. In terms of gonadal growth, the gonadosomatic index was similar between the three densities tested, with an average increase of 3%. H. diversicolor showed a positive growth rate at all densities tested, with weight gains ranging from 0.19 ± 0.024 g to 0.16 ± 0.010 g, while specific growth rate values ranged from 3.05 ± 0.16 %/day to 2.78 ± 0.098 %/day. Overall, this study has shown that juvenile H. diversicolor can be successfully reared using the sea urchin P. lividus wastes as the sole food source.
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Keywords
Poliquetas Cultura integrada Diversificação em Aquacultura Ouriço-do-mar comum Densidade Produção Ragworms Integrated rearing Aquaculture diversification Purple sea urchin Density Production