Spawning induction, fertilization essays and larval development of the sea urchin Paracentrotus lividus
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1
Escola Superior de Turismo e Tecnologia do Mar, Politécnico de Leiria, MARE – Marine and Environmental Sciences Centre, Portugal
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2
Direção Regional de Pescas, Centro de Maricultura da Calheta (CMC), 9370-135 Calheta, Madeira, Portugal
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3
Observatório Oceânico da Madeira (OOM), Portugal
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4
Centro Interdisciplinar de Pesquisa Marine e Ambiental (CIIMAR), Portugal
Sea urchin gonads (roe) are a prize product and broadly recognized as a delicacy for human consumption. Due to the increasing demand for this product by Asian and European countries, overfishing is causing a sharp decline in the wild stocks of Paracentotus lividus. During the last decade a significant increase in efforts to develop cost-effective methods to culture sea urchins has been observed including research aiming to optimize the reproduction in captivity conditions, being the development and survival of larval planktonic stages one of the bottlenecks for the echinoculture development.
For this study, P. lividus adults (n = 80), with test size superior of 35 mm, were collected in the intertidal rock pools of Reis Magos (32º38’44.24’’N; 16º49’26.53’’W) and Poças do Governador (32º37’59.00’’N; 16º56’36.33’’W) in the southern coast of Madeira island. The rearing system consisted of four 200 L tanks at 22,05 ± 0,707 ºC and a 90 L/h of water renovation. Every tank contained 15 sea urchins and feeding was established at 5% weight.day-1 of macroalgae collected in the sampling site. The maturation stage of the population was analyzed a priori by determining the gonadal index (GI) and by histological analysis of the gonads of a subsample of 20 sea urchins. Four different spawn inducing methods (agitation, addition of con-specific spermatozoa, addiction of microalgae and injection of KCl 0,5M) were evaluated by assessing the spawning response within 30 min., and survival of the induced sea urchins after five days. The most efficient method to induce spawning was used to perform the artificial fertilization of sea urchin eggs. The viable echinopluteus were then fed with diets of different microalgae (Dunaliella tertiolecta and Rhodomonas marina) comparing larvae growth and survival, when competence for settlement was achieved. The larval experimental design consisted of three triplicated treatments, in 7 L cylindroconical incubators at 21 ± 0,387 ºC. The microalgae rationing was established at 4000, 8000 and 16000 cells.ml-1 in treatment 1, 2 and 3, respectively for larvae (echinopluteus) with two pairs of arms. The microalgae concentration was doubled in all treatments with the increment of the 3rd and 4th pair of arms during the development of the echinopluteus. The GI was 3,89% ± 1,97 and the histological analysis demonstrated that 30% of the individuals were capable of spawning and 70% were in a spent phase, therefore, incapable of gamete release. The induction by agitation revealed to cause a higher percentage of mortality, 70% of the induced individuals, when compared with the other three methods, 10% for injection of KCl 0,5M and 0% for the addiction of both spermatozoa and microalgae. In the other and, the KCl demonstrated to be the more expedite and viable method, with a positive response from 30% of the induced individuals within the first 5 min. The addiction of microalgae proved to induce gamete release in 20% of the individuals, but over a period of 24h. The agitation method induced gamete release in 10% of the submitted individuals and the addiction of con-specific spermatozoa did not produced positive results. The preliminary results of the first larval development experiment using a R. marina diet showed that the echinopluteus attain the settlement phase within 21 days with higher survival rate in the treatment of lower microalgae concentration.
Acknowledgements
This study had the support of Fundação para a Ciência e Tecnologia (FCT), through the strategic project UID/MAR/04292/2013 granted to MARE - Marine and Environmental Sciences Centre. Sílvia Lourenço was financially supported by a post-doctoral grant form ARDITI (Regional Agency for Development of Research, Technology and Innovation of Madeira), Project M1420-09-5369-FSE-000001.
Keywords:
Echinoculture,
Echinopluteus,
Histology,
Paracentrotus lividus,
Spawn induction
Conference:
IMMR'18 | International Meeting on Marine Research 2018, Peniche, Portugal, 5 Jul - 6 Jul, 2018.
Presentation Type:
Poster Presentation
Topic:
Aquaculture
Citation:
Luís
R,
Pombo
A,
José
R,
Nogueira
N and
Lourenço
S
(2019). Spawning induction, fertilization essays and larval development of the sea urchin Paracentrotus lividus.
Front. Mar. Sci.
Conference Abstract:
IMMR'18 | International Meeting on Marine Research 2018.
doi: 10.3389/conf.FMARS.2018.06.00134
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Received:
28 Apr 2018;
Published Online:
07 Jan 2019.
*
Correspondence:
MD, PhD. Sílvia Lourenço, Direção Regional de Pescas, Centro de Maricultura da Calheta (CMC), 9370-135 Calheta, Madeira, Madeira, Portugal, slourenco2@gmail.com