Two decades of Pseudo-nitzschia spp. blooms and king scallop (Pecten maximus) contamination by domoic acid along the French Atlantic and English Channel coasts: Seasonal dynamics, spatial heterogeneity and interannual variability

Abstract

King scallop contamination (Pecten maximus) by domoic acid, a neurotoxin produced by some species of the diatom Pseudo-nitzschia, is highly problematic because of its lengthy retention in the bivalve tissue, leading to prolonged fishery closures. Data collected within the French Phytoplankton and Phycotoxin monitoring network (REPHY) over the 1995-2012 period were used to characterize the seasonal dynamics and the interannual variability of P.-nitzschia spp. blooms as well as the contamination of king scallop fishing grounds, in six contrasted bays distributed along the French Atlantic coast and English Channel. Monitoring revealed that these toxic events have become more frequent since the year 2000, but with varying magnitudes, frequencies and timing depending on the bay. Two bays, located in southern Brittany, exhibited both recurrent contaminations and high P.-nitzschia abundances. The Brest bay and the Seine bay were intermittently affected. The Pertuis Breton exhibited only one major toxic event related to an exceptionally intense bloom of P.-nitzschia in 2010, and the Saint Brieuc bay neither showed significant contamination nor high P.-nitzschia abundance. While high P.-nitzschia abundance appeared to be correlated to scallop toxicity, this study highlights the difficulty in linking P.-nitzschia spp. blooms to king scallop contamination through monitoring. Indeed, P.-nitzschia was determined at the genus level and data regarding species abundances and their toxicity levels are an absolute prerequisite to further assess the environmental control of ASP events. As results describe distinct P.-nitzschia bloom dynamics along the French coast, this may suggest distinct controlling factors. They also revealed that major climatic events, such as the winter storm Xynthia in 2010, can trigger toxicity in P.-nitzschia over a large spatial scale and impact king scallop fisheries all along the coast.

Influence of sudden salinity variation on the physiology and domoic acid production by two strains of Pseudo‐nitzschia australis

“…, Husson et al. ). As reported in several studies, the expected future increases in salinity fluctuations in coastal and estuarine areas, brought about by climate change and anthropogenic pressure, could potentially affect the frequency and intensity of Pseudo‐nitzschia blooms (IPCC , McCabe et al.…”

“…, Husson et al. ) as well as in many other parts of the world such as the North and South Americas (Anderson et al. , Bargu et al.…”

Managing the Agri-Food System of Watersheds to Combat Coastal Eutrophication: A Land-to-Sea Modelling Approach to the French Coastal English Channel

“…[17]) and diatoms (Pseudo-nitzschia spp. (PSN), [18][19][20][21]) in the Seine Bay, the Bay of Brest and South Brittany, but also macroalgae in the south on the Brittany coasts (Ulva spp., [22]), and mucilaginous algae north of the English Channel and the Southern Bight of the North Sea (Phaeocystis spp., [10]).…”

“…In particular, scallop fishery is greatly impacted by toxic events because, contrary to other filter shellfish, the scallop takes a very long time to decontaminate [26,27]. Two ASP toxic events that occurred between 2004 and 2011-2012 in the eastern English Channel affected scallop fishery in the Seine Bay and induced partial or total closure of fisheries [20].…”

Offshore aquaculture: Spatial planning principles for sustainable development

“…Factors such as depth, distance from port (and associated infrastructure and processing facilities), wave conditions, and storm activity modify transport, labor, construction, and maintenance costs (Kaiser, Snyder, & Yu, ; Klinger & Naylor, ). Additionally, risks due to climate variability, pollution, disease, and harmful algal blooms can vary spatially (e.g., Husson, Hernández‐Fariñas, Le Gendre, Schapira, & Chapelle, ) and may have an effect on the profitability of a farm.…”