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Publication
Long-term population status of two harvested intertidal grazers (Patella aspera and Patella candei), before (1996–2006) and after (2007–2017) the implementation of management measures
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Advisor(s)
Abstract(s)
Intertidal limpets are subject to harvesting pressure in regions, e.g. oceanic islands, where marine organisms are
a more accessible source of protein. These molluscs are very sensitive to human exploitation which often results
on a decrease of their densities and an over-representation of immature individuals, because of the loss of large sized reproductive specimens. Two species of exploited limpets (Patella aspera and Patella candei) were assessed
throughout 21 years, before (1996–2006) and after (2007–2017) the implementation of conservation measures
for their sustainable management in Madeira (North-eastern Atlantic Ocean). Different levels of anthropogenic
pressure were also taken in account in this comparative study: (i) proximity to coastal settlements (“Near” vs.
“Far”) and (ii) accessibility to the coast (North vs. South), that may be considered surrogates of harvesting
pressure on the intertidal of Madeira. The present results showed that the stocks of P. aspera and P. candei are
slightly recovered after regulatory measures entered into force, with an increase of mean shell length and
dominance of reproductive individuals (> 40 mm). P. aspera populations showed a clearer effect mainly due to
the higher exploitation rate relative to P. candei. Conservation measures prompted a positive effect on both
exploited limpet species, but further assessment studies are necessary to address the evolution of stocks over
time.
Description
Keywords
Limpets Size-structure Harvesting Management measures North-eastern Atlantic . Faculdade de Ciências da Vida
Citation
Sousa, R., Vasconcelos, J., Henriques, P., Pinto, A. R., Delgado, J., & Riera, R. (2019). Long-term population status of two harvested intertidal grazers (Patella aspera and Patella candei), before (1996–2006) and after (2007–2017) the implementation of management measures. Journal of Sea Research, 144, 33-38. https://doi.org/10.1016/j.seares.2018.11.002
Publisher
Elsevier