The importance of copepods as live feed on larval development of dusky grouper (Epinephelus marginatus Lowe, 1834)

Abstract

Event Abstract Back to Event The importance of copepods as live feed on larval development of dusky grouper (Epinephelus marginatus Lowe, 1834) Margarida Gamboa1*, Paula Moura1, 2, Márcio Moreira1, Sara Castanho1, Laura Ribeiro1, Rita Gonçalves3 and Maria E. Cunha1 1 Instituto Português do Mar e da Atmosfera (IPMA), Aquaculture Research Center, Portugal 2 Instituto Português do Mar e da Atmosfera (IPMA), Portugal 3 University of Madeira, Portugal Copepods are one of the major prey of early marine fish larvae in the natural habitat, because they present adequate nutritional value, stimulate feed response, and have a wide size range. Mesocosm systems simulate the natural environment, with the possibility of possessing copepods from all naupliar stages (Divanach and Kentouri 2000). Most of these ranged from 75µm to 1300µm which are the ideal size of prey for dusky grouper (Epinephelus marginatus) larvae with a mouth gape of 220-250 µm at first exogenous feeding and low survival at the end of larval production (Cunha et al. 2009, Toledo et al. 1999). The aim of this work was to determine if dusky grouper larvae choose specifically copepods when a mixture of different items are offer as food. Two different feeding treatments were tested in tree replicate tanks each. Treatment 1 was a phytoplankton mixture of Isochrysis galbana, Nannochloropsis oculata and protozoan Oxyrrhis marina. This system was initially supplemented with eggs (1 egg ml-1) and nauplii of Paracartia grani (0.006 individuals.ml-1 from day 0 to 13). Treatment 2 had a regular nursery feeding regime with I. galbana and N. oculata. To both treatments rotifers (Brachionus spp., 5 individuals.ml-1) were added from day 0 to 10, as well as artemia (Artemia sp., 1 nauplii.ml-1) from day 9 to 22 and dry feed from day 17 to 22 day. Rotifers and newly hatched Artemia nauplii were enriched to increase levels of protein. The copepods were produced at indoor tanks (200 L) at Aquaculture Research Centre, National Institute for the Sea and Atmosphere (EPPO-IPMA, Olhão, Portugal). Copepod adult population were fed with a mixture of Rhodomonas salina and Oxyrrhis marina, and the resting eggs collected daily by siphoning the bottom of the tanks and kept at 6 ºC and dark conditions until used. Dusky grouper larvae were reared at low density (2 larva l-1) from 1 to 22 days after hatching (DAH), with natural photoperiod (15L/9D), temperature and gentle aeration. Samples were collected at 5, 10, 15 and 22 DAH for identification of stomach content (microscopic and genetic identification) and stomach fullness Microscopic observations showed the presence of eggs and several pieces of copepod exoskeleton, from day 5 to 22 DAH. P. grani eggs and nauplii were the predominant prey of dusky grouper larvae, during the first stages of development at Treatment 1 with larvae showing higher stomach fullness. Stomach content genetic analysis (PCR plus/minus) confirms the presence of P. grani eggs and nauplii in the stomach of the larva from Treatment 1 in all the sampling points. Acknowledgements This work was financed by DIVERSE (PTDC/MAR/113786/2009) project. MM’s has a PhD grant from FCT (SFRH/ BD/118601/ 2016). References Cunha ME, Quental H, Barradas A, Pousão-Ferreira P, Cabrita E, Engrola S. 2009. Rearing larvae of dusky grouper, Epinephelus marginatus (Lowe, 1834),(Pisces: Serranidae) in a semi-extensive mesocosm| La cría de larvas de mero, Epinephelus marginatus (Lowe, 1834),(Pisces: Serranidae), en un mesocosmos de tecnología semiextensiva. Scientia Marina.73:201-212. Divanach P, Kentouri M. 2000. Hatchery techniques for specific diversification in Mediterranean finfish larviculture. In: Recent advances in Mediterranean aquaculture finfish species diversification, Cahiers Options Méditerranéennes. Zaragoza: CIHEAM. Toledo JD, Golez MS, Doi M, Ohno A. 1999. Use of copepod nauplii during early feeding stage of grouper Epinephelus coioides. Fisheries Science.65:390-397. Keywords: Copepod nauplii, Mesocosm system, Paracartia grani, Stomach contents, genetic analysis Conference: IMMR'18 | International Meeting on Marine Research 2018, Peniche, Portugal, 5 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Aquaculture Citation: Gamboa M, Moura P, Moreira M, Castanho S, Ribeiro L, Gonçalves R and Cunha ME (2019). The importance of copepods as live feed on larval development of dusky grouper (Epinephelus marginatus Lowe, 1834). Front. Mar. Sci. Conference Abstract: IMMR'18 | International Meeting on Marine Research 2018. doi: 10.3389/conf.FMARS.2018.06.00110 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 May 2018; Published Online: 07 Jan 2019. * Correspondence: Miss. Margarida Gamboa, Instituto Português do Mar e da Atmosfera (IPMA), Aquaculture Research Center, Lisbon, Portugal, agamboa@ipma.pt Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Margarida Gamboa Paula Moura Márcio Moreira Sara Castanho Laura Ribeiro Rita Gonçalves Maria E Cunha Google Margarida Gamboa Paula Moura Márcio Moreira Sara Castanho Laura Ribeiro Rita Gonçalves Maria E Cunha Google Scholar Margarida Gamboa Paula Moura Márcio Moreira Sara Castanho Laura Ribeiro Rita Gonçalves Maria E Cunha PubMed Margarida Gamboa Paula Moura Márcio Moreira Sara Castanho Laura Ribeiro Rita Gonçalves Maria E Cunha Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.