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The Effect of Abiotic and Biotic Variables on Culturing Conditions of Calanoid Copepod Acartia Grani

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The Effect of Abiotic and Biotic Variables on Culturing Conditions of Calanoid Copepod Acartia Grani The effect of abiotic and biotic variables on culturing conditions of Calanoid copepod Acartia grani Luis Bernardo dos Santos Sumares Dissertation for the Master in Marine Sciences – Marine Resources 2012 Luís Bernardo dos Santos Sumares The effect of abiotic and biotic variables on culturing conditions of Calanoid copepod Acartia grani Dissertation application to the master degree in Marine Sciences – Marine Resources submitted to the Institute of Biomedical Sciences Abel Salazar, University of Porto. Supervisor: Natacha Nogueira Researcher Mariculture Center of Calheta (CMC) Co-Supervisor: António Afonso Associate Professor Institute of Biomedical Sciences Abel Salazar, University of Porto 1 Master´s degree in Marine Sciences – Marine Resources | Bernardo Sumares Preface The work described in this document was made between the months of November 2011 and September 2012, initially on IPIMAR - Algarve, and later at the Mariculture Center of Calheta (CMC), in Madeira Island. The work was organized in two phases: one was to acquire knowledge of microalgae and copepods in IPIMAR; and the second phase, performed at CMC facilities, was the performance of all the experiments that gave rise to this thesis. i Master´s degree in Marine Sciences – Marine Resources | Bernardo Sumares ii Master´s degree in Marine Sciences – Marine Resources | Bernardo Sumares Acknowledgements To my super parents Paula e Angelino that give me all the support and love for successfully completes another important stage of my life. The wise words of my father who helped me a lot: “Depois da tempestade vem a bonança”. My sister Carolina and Rik for always being available to help me even in the hours of hard work always put my work first. To Catarina for all your love and affection that was always present when I needed. To my supervisor Natacha Nogueira who was the basis of this work, for the advices, for the difficult decisions, for their patience to answer the obvious questions, for being always present when I needed, for arrange the material needed for the experiments, doubtless the best supervisor that I could ever have. And to my co-supervisor Professor António Afonso for the excellent advices and availability that always manifested. I would like to thank the entire staff of Centro de Maricultura da Calheta (CMC) for helping me whenever I needed. To Dr. Carlos Andrade who provide a laboratory where I cloud make all my experiences and had my microalgae stock to feed the copepods. To all staff of IPIMAR-Algarve, in particularly Drª Maria Emília Cunha that spent all his knowledge of the Acartia grani, showing how fascinating is the world of zooplankton, and how this world has a lot to show us. To Paulo Jorge, without him I could not be able to produce any type of microalgae, and now I´m proud to have been able to produce the demanding microalgae Rhodomonas. To Drª Nereida Cordeiro from Centro de Competências de Ciências Exatas e de Engenharia – Universidade da Madeira that had available she laboratory and together with Miguel e Marisa who give me a precious help. iii Master´s degree in Marine Sciences – Marine Resources | Bernardo Sumares iv Master´s degree in Marine Sciences – Marine Resources | Bernardo Sumares Abstract Calanoid copepods, incluinding species of the genus Acartia are commonly used for larval diets of marine finfish. The interest in copepods for marine fish aquaculture is growing especially in large-scale culturing. However, studies quantifying the optimal conditions for intensive copepod production are generally lacking for most species. The present thesis was conducted to evaluate the effect of abiotic and biotic variables on culturing condition of Calanoid copepod Acartia grani. The egg hatching rate (EHR) at different temperatures showed a clear trend of increasing EHR in warmer temperatures; 36 hours after incubation, 74.7% of eggs had hatched in the 28°C treatment (Chapter I). In Chapters II to Chapter V we analyzed the egg hatching rate (EHR), egg production (EP) and population growth of the different variables imposed. The highest egg hatching observed within each variable analyzed was: (1) 60%, 72h after incubation at 24°C within the temperature experiment (Chapter II) ; (2) the photoperiod experiment (Chapter III) 21%, 48h after incubation with light regimen of 6L:18D within the photoperiod experiment. (3) 44.2% at 72h in the Rho+T-Iso diet treatment (Chapter IV) and finally (4) 30.4%, 48 hours after incubation in the diet experiments using heterotroph Oxyrris marina (Chapter V). Egg production results varied among variables and within each experiment best results were found for: 18ºC, which had an EP of 10.5±1.5 eggs female-1day-1; photoperiod of 12Light:12Dark achieved an EP of 9.5±1.9 eggs female-1day-1; diet with Rhodomonas marina obtained 4.7±0.9 eggs female-1day-1; and finally in Chapter V, the diet Rhodomonas marina + Oxyrrhis marina had 3.7±0.6 eggs female-1day-1. Regarding results of population growth when all developmental stages were included , we found that the temperature of 18°C produced a population increase from 12 to 663.0±52.2 individuals in 12 days (Chapter II); photoperiod 12Light:12Dark increased to a final population of 964.3±410.7 copepods. Last two experiments that evaluated the use of different diets revealed a population increase from 12 to 1783.0±560.6 individuals with the use of a binary diet composed by Rhodomonas marina + Tahitian strain of Isochrysis sp.; and in the last experiments (Chapter V) the best diet was once more, a binary diet composed by Rhodomonas marina and Oxyrrhis marina with a mean final population of 1795.0±451.8 copepods. Cannibalism occurred in all tested densities (125; 250; 500; 1000; and 2000 ind./L) (Chapter VII) and conclusion was that 125ind./L induced significantly lower cannibalistic rates. In Chapter VI we analysed the lipid and fatty acids composition of Acarti grani with different diets. The results show a moderate level of total lipids in the two samples. In the first diet (Rho) a total lipid content of 9.4±2.2% was found and for binary diet Rho+Oxy, v Master´s degree in Marine Sciences – Marine Resources | Bernardo Sumares lipid content was of 8.6±0.1%. In the fatty acid composition no significance differences were observed (p>0.05). Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were present in both samples in high amounts, witn a mean ratio of DHA/EPA of 2.29 for copepods fed on Rhodomonas and 2.18 for copepods fed Rhodomonas + Oxyrrhis. In general, we concluded that the following parameters are a good choice for maximization of the culture of A.grani; Temperature: 24°C; Photoperiod: 12Light:12Dark; Diet: Rhodomonas marina + Oxyrrhis marina; Density: 150ind./L. vi Master´s degree in Marine Sciences – Marine Resources | Bernardo Sumares Resumo Os copépodes Calanóides, em particular as espécies do género Acartia são geralmente usadas como dieta para larvas de peixes ósseos. O interesse nos copépodes em aquacultura de peixes marinhos tem aumentado, em especial na produção de culturas em grande escala. No entanto, para a maioria das espécies existem poucos estudos que refiram as condições óptimas de cultura. A presente tese foi realizada para avaliar o efeito de variáveis abióticas e bióticas nas condições de cultura do copépode Calanóide Acartia grani. As taxas de eclosão (EHR) em relação à temperatura mostraram que aumentavam com a subida da mesma; Após 36 horas de incubação, 74.7% dos ovos tinham eclodido no tratamento de 28°C. Do Capítulo II até ao Capítulo V analisamos as taxas de eclosão (EHR), a produção de ovos (EP) e o crescimento da população com as diferentes variáveis impostas. As maiores taxas de eclosão observadas entre as variáveis analisadas foram: (1) experiência da temperatura (Capítulo II) apresentou uma EHR de 60%, 72horas após incubação dos ovos a 24°C; (2) a experiência do fotoperíodo obteve uma EHR de 21%, 48h após incubação com um regime de 6Luz:18Escuro (Capítulo III); (3) na experiência das dietas (Capítulo IV) foi encontrada uma EHR de 44.2% às 72h na dieta Rho+T-Iso; (4) na experiência das dietas utilizando o organismo heterotrófico Oxyrrhis marina a maior taxa de eclosão foi verificada na dieta T-Iso (30.4%) 48h após a incubação (Capítulo V). Os resultados da produção de ovos variaram com as diferentes variáveis e entre as experiências. Os melhores resultados foram: 18°C, com uma produção de 10.5±1.5 ovos fêmea-1dia-1; para o fotoperíodo de 12Luz:12Escuro a EP foi de 9.5±1.9 ovos fêmea-1dia-1; finalmente na dieta de Rhodomonas marina + Oxyrrhis marina, a EP máxima foi de 3.7±0.6 ovos fêmea-1dia-1. Em relação aos resultados do crescimento da população, quando todas as fases foram consideradas (incluindo ovos), a temperatura de 18°C apresentou um crescimento dos 12 para 663.0±52.2 indivíduos em 12 dias (Capítulo II) e o fotoperíodo 12Luz:12Escuro teve uma população final de 964.3±410.7 copépodes. As últimas duas experiências em que foi analisado o papel das diferentes dietas, revelaram um aumento da população de 12 para 1783.0±560.6 indivíduos com o uso de uma dieta binária composta por Rhodomonas marina + Tahitian strain of Isochrysis sp. e na última experiência (Capítulo V) os melhores resultados foram uma vez mais com uma dieta binária composta por Rhodomonas marina e Oxyrrhis marina, onde foi verificado uma população média de 1795.0±451.8 copépodes, após 12 dias de cultura. vii Master´s degree in Marine Sciences – Marine Resources | Bernardo Sumares O canibalismo ocorreu em todas a densidades testadas (125; 250; 500; 1000; e 2000 ind./L) (Capítulo VII) e a conclusão foi que com 125ind./L as taxas de canibalismo eram significativamente inferiores.
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