Contrasting effects of protection from harvesting in populations of two limpet species in a recently established marine protected area

Abstract

SUMMARY: This study aimed to evaluate the effects of protection from extractive activities on the population structure of two limpets of commercial interest, Patella ulyssiponensis and Patella candei crenata. We evaluated the status of these populations in La Palma Marine Protected Area (MPA), Canary Islands, and in comparable unprotected areas in the lower intertidal zone of the same island. We showed that the density of P. ulyssiponensis depended greatly on the level of protection, whereas the effects of protection on the density of P. candei crenata were less clear and only differences between sites were found. These results are probably linked to the different habitat affinities of the two species studied and demonstrate the need to tailor conservation strategies in MPAs to individual species for appropriate management of local shellfish resources.Keywords: marine protected area, shellfishing, intertidal habitat, Patella ulyssiponensis, Patella candei crenata, Canary Islands.RESUMEN: Diferentes efectos de la protección frente al marisqueo en las poblaciones de dos especies de lapas en una reserva marina de reciente creación. -Este estudio tiene por objetivo evaluar el efecto de la protección frente a actividades extractivas sobre la estructura poblacional de las especies de lapas de interés marisquero, Patella ulyssiponensis y Patella candei crenata. Para ello, se evaluó el estado de sus poblaciones en el intermareal inferior de localidades situadas tanto dentro de la Reserva Marina de La Palma (islas Canarias) como en zonas no protegidas de características similares. Se observó que la densidad de P. ulyssiponensis depende en gran medida del nivel de protección, mientras que en el caso de P. candei crenata el efecto de la protección sobre la densidad no fue tan claro, observándose diferencias sólo entre localidades. Estos resultados probablemente se relacionan con las distintas afinidades de hábitat entre las especies estudiadas, lo que indica la necesidad de proteger áreas más heterogéneas que incluyan una variedad de hábitat adecuada para la diversidad de especies de una región, asegurando una correcta regulación y conservación de los recursos marisqueros.Palabras clave: reserva marina, marisqueo, hábitat intermareal, Patella ulyssiponensis, Patella candei crenata, islas Canarias.

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

“…The observed recovery pattern in the exploited populations of both limpets agreed with Martins (2009) that observed the same correlation between limpets' abundances and the proximity to coastal settlements in Azores (NE Atlantic). Also, when considering the control sites, these results are concurrent with López et al (2012) that observed that sites where harvesting is not allowed, e.g. marine protected areas (MPAs), assemblages had larger individuals and higher abundances, and also an increase of their populations was observed.…”

“…The loss of large individuals produces cascading effects on the biology of limpets in exploited populations, including changes in lifehistory parameters, demographics, reproductive success, genetics, as well as changes in ecological interactions and limpet behaviour (Fenberg and Roy, 2008;Espinosa et al, 2009;López et al, 2012;Henriques et al, 2017). In the most extreme cases, harvesting pressure is recognized to have led to the high fragmentation of limpet assemblages as occurred for P. candei crenata and P. aspera in the Canaries (Riera et al, 2016) and even to the disappearance of populations of P. ferruginea, an endemic and endangered species from the Mediterranean Sea (Espinosa, 2009), and of the endemic species Cellana sandwicensis (Pease, 1861), Cellana exarata (Reeve, 1854) and Cellana talcosa (Gould, 1846) in Hawaii (Valledor, 2000).…”

Disentangling the genetic and morphological structure of Patella candei complex in Macaronesia (NE Atlantic)

“…Legislation does not differ much among regions, with the establishment of limpet no‐take areas, minimum legal catch sizes, and seasonal fishing closures. Unfortunately, these actions have been largely ineffective in protecting such resource (Diogo, Pereira, & Schmiing, ; López et al., ; Martins et al., ; Riera et al., ), mostly because of illegal harvesting and lack of or insufficient enforcement. Protective measures need to be adjusted to the particular life‐history traits of P. candei in each archipelago (e.g., temporal variation in reproduction, recruitment, population dynamics).…”

The exploitation of limpets in a Mediterranean Marine Protected Area: assessing the effectiveness of protection in the intertidal zone

“…Kido & Murray, 2003;Branch & Odendaal, 2003;Martins et al, 2011;López et al, 2012). Highly vulnerable species are more likely to benefit from the establishment of protected areas, as demonstrated by case studies on large limpets that are often present within MPAs and other protected areas (Fenberg & Roy, 2012;Espinosa et al, 2014;García-Gómez et al, 2015).…”