Reproduction of the sea urchin Loxechinus albus across a bathymetric gradient in the Chilean Inland Sea

• Published in: Revista de biología marina y oceanografía 2012-08, Vol.47 (2), p.257-272
• Main Authors: Niklitschek, Edwin, Matamala, Manira, Arevalo Nazrala, Alejandra, Codjambassis, José, Neculman, Mónica, Molinet, Carlos, Díaz Gómez, Patricio Andrés, Diaz, Manuel, Moreno, Carlos A
• Format: Article
• Language: English
• Subjects: capacidad reproductiva; Deep patches; desove inducido; induced spawn; Parches profundos; reproductive capacity
• ISSN: 0717-3326
• DOI: 10.4067/S0718-19572012000200008

The reported bathymetric distribution of commercial sea urchin species varies globally from the intertidal zone down to a depth of a hundred meters or more, although few studies have been conducted at depths >25 m. Urchins that inhabit shallow sites are expected to have access to more food and to display greater gonad development than those from deeper habitats. The latter could, however, play an important reproductive role by enhancing the resilience of the exploited populations. The objective of this study was to verify the existence of deep reproductively active patches of the edible sea urchin Loxechinus albus in two fishing areas of the Chilean Inland Sea, and compare the main reproductive features of these patches over the 0-100 m bathymetric gradients. We evaluated the gonadic index (GI) and KCl-induced spawning in adult L. albus collected between the surface and 100 m depth between September 2008 and March 2009. Urchins were relatively abundant up to 15 m depth, few to 60 m depth and only one patch of urchins was found between 60 and 100 m depth. Asynchrony was observed in the GI and induced spawning between strata and sampling areas, suggesting that urchins located between 30 and 100 m may be reproductively active and may asynchronously spawn during the breeding season, although their potential contribution to the population dynamic is unknown. Future studies should examine the role of the scarce deep-water aggregations for the regional population dynamics of L. albus, in particular in areas where shallow populations have been heavily fished. La distribución batimétrica reportada para erizos de interés comercial va desde el intermareal hasta cientos de metros, aunque estudios reportados a profundidades mayores que 25 m son escasos. Se espera que erizos que habitan sitios someros tengan acceso a más alimento y desplegar un mayor desarrollo gonádico que aquellos erizos de hábitat más profundos. Los erizos en hábitat profundo pueden jugar un rol importante para mejorar la resiliencia de las poblaciones explotadas ubicadas en hábitat someros. El objetivo de este estudio fue verificar la existencia de parches del erizo Loxechinus albus reproductivamente activos en un gradiente batimétrico desde 0 a 100 m de profundidad en dos áreas de pesca del mar interior chileno. Para esto se evaluó el índice gonádico (IG) y el desove inducido con KCl en ejemplares adultos de L. albus recolectados entre la superficie y los 100 m de profundidad entre septiembre de 20