Manila clam (Ruditapes philippinarum) in France: Fishing activity, governance and present knowledge challenges regarding its biology and ecology

Abstract

Originally introduced to France in the 1970s for aquaculture purposes, the clam Ruditapes philippinarum (Adam and Reeve, 1850) has thrived in favourable conditions across numerous sites along the Bay of Biscay, English Channel and Mediterranean coasts forming neo-naturalized populations. It is harvested by both recreational and professional fishers, with an estimated production ratio of 2.4 for both activities combined. Total French commercial fishing production is roughly estimated at around 2000 to 3000 tons per year. This activity is managed by three types of regulation at different scales: European (Minimum Conservation Reference Size - MCRS), national (licenses), and regional. Regional instruments govern fishing practices by setting spatial and temporal access rules to fishing grounds (also referred to as deposits), prohibiting certain gear types at the local scale, determining the minimum size of clam fishing (above MCRS) and setting fishing quotas. Not all of them are implemented everywhere; most often, they are based on stock assessment results and specific research programs, which are not available in every location. This article first provides a review of available information on current Manila clam production in France, and its regulation. Second, it offers an overview of recent knowledge mobilized for management purposes. This overview covers biological and ecological processes (i.e. population dynamics, reproduction and spawning, habitats considerations, biotic interactions and infectious diseases), and enables us to identify future research prospects of interest.