Biological characterization of the reproductive cycle of the sea urchin (Paracentrotus lividus) in the western central region of Portugal (Peniche)
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1
Mare – Marine and Environmental Sciences Centre, School of Tourism and Maritime Technology, Polytechnic Institute of Leiria, 2520-641 Peniche, Portugal
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2
Linking Landscape, Environment, Agriculture and Food Research Unit (LEAF), Instituto Superior de Agronomia, University of Lisbon, Tapada da Ajuda, Lisbon, Portugal
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3
MARE – Marine and Environmental Sciences Centre, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra, Portugal
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4
CFE – Centre for Functional Ecology, Department of Life Science, University of Coimbra, Apartado 3046, 3001-401 Coimbra, Portugal
Paracentrotus lividus and others sea urchins species have long been used in embryology and developmental biology, as optimal experimental models, and many aspects of male and female gamete development are well known, especially from a cellular point of view. Sea urchins are ancient organisms that lack many of the organs found in other animals. They have no specialized respiratory or circulatory system and they have no specialized excretory organs. Basically, sea urchins are composed by the digestive, water vascular and reproductive systems, which are all surrounded by a hard shell, also known as test. The size of the gonads (also known as roe) varies according to the maturation stage. In the early stages, gonads can be very small. When the last stages of maturation are reached, gametes increase in size and number, so that the gonads may occupy most of the inner shell space. After spawning, gonads decreased in size, due to the gametes’ release.
Recently, sea urchin’s gonads have been considered one of the most appreciated delicacies in certain regions of Europe. In Peniche (central Atlantic coast of Portugal), destructive harvesting methods and high legal amount of sea urchins allowed to be captured, may be contributing to the decline of the populations and causing the consequent imbalance of flora and fauna in their native ecosystems. In order to protect and monitor the Paracentrotus lividus populations, it is crucial to study their dynamics and reproductive biology.
In this study, 30 individuals were collected monthly at the beach of Abalo (Peniche, Portugal: 39°22'12.69"N; 009°23'7.07"W), over a period of a 12 months (July 2015 to June 2016). Test diameter, total weight (TW), gonads weight (GW) and gonadal index (GI) were determined. Then, 10 individuals were used for histological analyses of the gonadal tissue, measurement of the oocytes diameter and population sex ratio.
The collected data showed that gonadal growth occurred during spring, when the temperature rose. In the beginning of the summer, spawning (stage V) events happened and the gonadal index decreased, as the gametes were released. After spawning (stage VI), sea urchins endured a long recovery period (stage VII to stage I), during which nutritional phagocytes were responsible for the absorption of the unspent gametes and all of the other substances, in order to start a new cycle. These events seemed to happen in the autumn. The oocyte diameter increased along with the gonadal growth, following the same seasonal pattern.
Acknowledgements
This study had the support of Portuguese Foundation for Science and Technology (FCT), through the strategic project UID/MAR/04292/2013 granted to MARE.
Keywords:
annual cycle,
Reproduction,
gonadal index,
oocyte diameter,
echinoderm
Conference:
IMMR | International Meeting on Marine Research 2016, Peniche, Portugal, 14 Jul - 15 Jul, 2016.
Presentation Type:
Poster presentation
Topic:
Aquaculture
Citation:
Raposo
A,
Ramos
R,
Anjos
CM,
Pombo
A,
Tecelão
C,
Gonçalves
S,
Baptista
T and
Ferreira
S
(2016). Biological characterization of the reproductive cycle of the sea urchin (Paracentrotus lividus) in the western central region of Portugal (Peniche).
Front. Mar. Sci.
Conference Abstract:
IMMR | International Meeting on Marine Research 2016.
doi: 10.3389/conf.FMARS.2016.04.00035
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Received:
13 May 2016;
Published Online:
13 Jul 2016.
*
Correspondence:
Prof. Susana M. F. Ferreira, Mare – Marine and Environmental Sciences Centre, School of Tourism and Maritime Technology, Polytechnic Institute of Leiria, 2520-641 Peniche, Peniche, 2520-641, Portugal, susana.ferreira@ipleiria.pt