João Delgado

By Paulo Henriques, João Delgado and Ricardo Sousa

This work reviews a broad spectrum of subjects associated to Patellid limpets’ biology such as growth, reproduction, and recruitment, also the consequences of commercial exploitation on the stocks and the effects of marine protected areas (MPAs) in the biology and populational dynamics of these intertidal grazers. Knowledge of limpets’ biological traits plays an important role in providing proper background for their effective management. This chapter focuses on determining the effect of biotic and abiotic factors that influence these biological characteristics and associated geographical patterns. Human exploitation of limpets is one of the main causes of disturbance in the intertidal ecosystem and has occurred since prehistorical times resulting in direct and indirect alterations in the abundance and size structure of the target populations. The implementation of MPAs has been shown to result in greater biomass, abundance, and size of limpets and to counter other negative anthropogenic effects. However, inefficient planning and lack of surveillance hinder the accomplishment of the conservation purpose of MPAs. Inclusive conservation approaches involving all the stakeholders could guarantee future success of conservation strategies and sustainable exploitation. This review also aims to establish how beneficial MPAs are in enhancing recruitment and yield of adjacent exploited populations.

Part of the book: Organismal and Molecular Malacology

By Ricardo Sousa, João Delgado, José A. González, Mafalda Freitas and Paulo Henriques

In this review article, the authors explore a broad spectrum of subjects associated to marine snails of the genus Phorcus Risso, 1826, namely, distribution, habitat, behaviour and life history traits, and the consequences of anthropological impacts, such as fisheries, pollution, and climate changes, on these species. This work focuses on discussing the ecological importance of these sentinel species and their interactions in the rocky shores as well as the anthropogenic impacts to which they are subjected. One of the main anthropogenic stresses that affect Phorcus species is fisheries. Topshell harvesting is recognized as occurring since prehistoric times and has evolved through time from a subsistence to commercial exploitation level. However, there is a gap of information concerning these species that hinders stock assessment and management required for sustainable exploitation. Additionally, these keystone species are useful tools in assessing coastal habitat quality, due to their eco-biological features. Contamination of these species with heavy metals carries serious risk for animal and human health due to their potential of biomagnification in the food chain. Thus, the use of these species as bioindicators is warranted to the establishment of conservation measures targeting marine coastal environments. Climate change increases the level of environmental stress to which intertidal organisms are subjected to, affecting the functioning of biological systems at different levels of organization. Phorcus species have been widely used as indicators of the effect of climate change on local disturbances of intertidal ecosystems and geographic distribution shifts of these organisms. Further studies concerning biological parameters of Phorcus species and how they react to exploitation, pollution, and climate change will consolidate these species as indicators of large-scale ecological impacts of anthropogenic activities.

Part of the book: Biological Resources of Water