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Potential impact of harvesting management measures on the reproductive parameters of the limpets Patella aspera and Patella candei from Madeira Island

2019; Elsevier BV; Volume: 226; Linguagem: Inglês

10.1016/j.ecss.2019.106264

1096-0015

Ricardo Sousa, Joana Vasconcelos, Rodrigo Riera, Ana Rita Pinto, João Delgado, Paulo Henriques,

Marine and fisheries research

Intertidal and shallow subtidal molluscs are highly sensitive to overharvesting because of their restricted habitat, limited mobility and easy access to humans. Several parameters have been previously used to determine their exploitation status, e.g. sizes, abundances and reproductive stages. Herein the reproductive parameters of two exploited limpets, Patella candei and the protandrous hermaphrodite Patella aspera were examined. Limpets were collected "before" (1996–2006) and "after" (2007–2017) the implementation of management measures aiming to preserve limpet populations in Madeira Island (NE Atlantic Ocean). The proportion of reproductive individuals increased approximately 14% after the implementation of management measures for both species. An increase in the size and age at first maturity of both species (from 34.6 to 37.5 mm in P. aspera and from 33.4 to 37.4 mm in P. candei) also occurred after such implementation. "Before" samples of P. aspera showed male-biased populations (1.7:1) shifting towards a balanced sex ratio (1:1) after the regulations. No "before" nor "after" sex ratio variations were observed in P. candei populations. Reproductive parameters revealed feasible to determine the efficiency of the implementation of management measures and to detect a slight improvement in reproductive potential of both limpet species.