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Copyright © Marine Biological Association of the United Kingdom 2010. ; There is clear evidence that marine reserves can be used as effective tools to foster the recovery of disturbed ecosystems. In the Azores, intense exploitation of the patellid limpets Patella candei and P. aspera has led to a rapid decline in their populations and subsequent collapse of the fishery in 1985. In 1993, legislation was passed to protect limpets, including the establishment of limpet protected zones (LPZs) where harvesting was completely prohibited. Outside LPZs, a seasonal fishing closure prohibited the harvesting of limpets from October to May. Here we examine the effect of such measures 16 years after they were put into practice. In each of the 3 years examined, limpet density, biomass and size were generally similar both inside and outside the LPZs. In addition, there were clear signs of exploitation as most individual limpets inside the LPZ were smaller than the legal catch size suggesting that illegal harvesting was taking place. Observations confirmed that illegal harvesting of limpets was common both inside and outside LPZs. Lack of enforcement of regulations is therefore a likely reason for the failure of legislation to protect limpet populations and facilitate stock recovery.

Patellid limpets are ecologically important keystone grazers having a long history of overexploitation in the Macaronesian Archipelagos (NE Atlantic islands), where some species, such as Patella aspera, are under serious risk.[1, 2] Patella aspera is a protandric sequential hermaphrodite species with external fertilization, in which individuals start off as males but may undergo a sex reversal with age.[3] Hence, exploitation tends to focus on the larger females in the population as larger limpets (predominantly females) are selectively removed. Despite conservation legislation in Canaries, Madeira and Azores, limpets are under severe pressure and few individuals survive long enough to become females, a phenomenon that severely restricts the effective population size.[4] New conservation actions for the protection and sustainable use of limpets in Macaronesian Archipelagos are urgently needed and should be based on a multidisciplinary framework based on knowledge of the population dynamics and connectivity of this species.