• European Marine Science
• ArchiMer - Institutional Archive of Ifremer close

Ce document est réalisé dans le cadre du projet « Système d’Informations Halieutiques » (SIH) de l’Ifremer, qui constitue le réseau d’observation des ressources halieutiques et des usages associés. Ce projet s’inscrit dans la mission de service d’intérêt public de l’Ifremer consistant à « connaître, évaluer et mettre en valeur les ressources des océans et permettre leur exploitation durable ». Outre la collecte des données pertinentes permettant l’analyse du secteur des pêches, le SIH a en charge l’élaboration d’indicateurs sur les flottilles de pêche et leur restitution sous forme de synthèses aux différents acteurs de la filière pêche et du grand public.

Background: To understand how local ecological knowledge changes and adapts, here in the case of the recent introduction of plant species, we report the knowledge and perceptions of the Ndjuka (Maroon) of French Guiana concerning two tree species, Acacia mangium and niaouli(Melaleuca quinquenervia), which are categorized as “invasive alien plants” in the savannas of their territory. Methods: To this end, semi-structured interviews were conducted between April and July 2022, using a pre-designed questionnaire, plant samples and photographs. The uses, local ecological knowledge, and representations of these species were surveyed among populations of Maroon origin in western French Guiana. All responses to closed questions collected during the field survey were compiled into an Excel spreadsheet in order to perform quantitative analyses, including the calculation of use reports (URs). Results: It appears that the local populations have integrated these two plant species, which are named, used and even traded, into their knowledge systems. On the other hand, neither foreignness nor invasiveness seem to be relevant concepts in the perspective of the informants. The usefulness of these plants is the determining factor of their integration into the Ndjuka medicinal flora, thus resulting in the adaptation of their local ecological knowledge. Conclusion: In addition to highlighting the need for the integration of the discourse of local stakeholders into the management of "invasive alien species”, this study also allows us to observe the forms of adaptation that are set in motion by the arrival of a new species, particularly within populations that are themselves the result of recent migrations. Our results furthermore indicate that such adaptations of local ecological knowledge can occur very quickly.

Les systèmes d'informations géographiques (SIG) permettent de regrouper des données spatialisées de natures diverses (bases données, résultats de modèles ...). Le recoupement de ces données permet de créer des indices de productivité. Geographical information systems collect and integrate geographically referenced data of diverse nature (database, model results, etc.). Comparing information from different sources can help formulate productivity indexes.

Interactions and coordination between conspecific individuals have produced a remarkable variety of collective behaviours. This co-operation occurs in vertebrate and invertebrate animals and is well expressed in the group flight of birds, fish shoals and highly organized activities of social insects. How individuals interact and why they co-operate to constitute group-level patterns has been extensively studied in extant animals through a variety mechanistic, functional and theoretical approaches. Although collective and social behaviour evolved through natural selection over millions of years, its origin and early history has remained largely unknown. In-situ monospecific linear clusters of trilobite arthropods from the lower Ordovician (ca 480 Ma) of Morocco are interpreted here as resulting either from a collective behaviour triggered by hydrodynamic cues in which mechanical stimulation detected by motion and touch sensors may have played a major role, or from a possible seasonal reproduction behaviour leading to the migration of sexually mature conspecifics to spawning grounds, possibly driven by chemical attraction (e.g. pheromones). This study confirms that collective behaviour has a very ancient origin and probably developed throughout the Cambrian-Ordovician interval, at the same time as the first animal radiation events.

During the six Heinrich events of the last 70 kyr, episodic calving from the circum-Atlantic ice sheets released large numbers of icebergs into the North Atlantic. These icebergs and associated meltwater flux are hypothesized to have led to a shutdown of Atlantic Meridional Overturning Circulation and severe cooling in large parts of the Northern Hemisphere. However, due to the limited availability of high-resolution records, the magnitude of sea surface temperature (SST) changes related to the impact of Heinrich events on the midlatitude North Atlantic is poorly constrained. Here we present a record of U-37(K)-based SSTs derived from sediments of Integrated Ocean Drilling Project Site U1313, located at the southern end of the ice-rafted debris (IRD) belt in the midlatitude North Atlantic (41 degrees N). We demonstrate that all six Heinrich events are associated with a rapid warming of surface waters by 2-4 degrees C in a few thousand years. The presence of IRD leaves no doubt about the simultaneous timing and correlation between rapid surface water warming and Heinrich events. We argue that this warming in the midlatitude North Atlantic is related to a northward expansion of the subtropical gyre during Heinrich events. As a wide range of studies demonstrated that in the central IRD belt Heinrich events are associated with low SSTs, these results thus identify an antiphased (seesaw) pattern in SSTs during Heinrich events between the midlatitude (warm) and northern North Atlantic (cold). This highlights the complex response of surface water characteristics in the North Atlantic to Heinrich events that is poorly reproduced by freshwater hosing experiments and challenges the widely accepted view that, within the IRD belt of the North Atlantic, Heinrich events coincide with periods of low SSTs.

During recent years, mass mortalities of cultured scallops became more frequent in Peruvian bays. One of the main drivers related to these mortalities was hypoxic events. This study was designed to understand the hypoxia phenomenon in these bays and to assess how the Peruvian scallop, Argopecten purpuratus, can cope with reduced oxygen levels in seawater based on individual size. First, we analyzed the relationships between dissolved oxygen saturation and other environmental parameters (the Coastal El Niño Index, temperature, salinity and pH) in bottom seawater, the frequency and intensity of hypoxic events in two main culture areas (Sechura and Paracas Bays), and their relationship with scallop mass mortalities. Then, we performed experiments with two size groups of A. purpuratus (31 and 80 mm shell height; seed and commercial size, respectively) to assess their respective survival time under severe hypoxia (1% oxygen saturation) at 16°C and a salinity of 35. Finally, the results of the field records and the experimental data are used to suggest ways to improve scallop cultivation along the Peruvian coast.

A new genus and species of ophidiid fishes, Ventichthys biospeedoi, is described based on two male specimens caught in the French BIOSPEEDO expedition to the South East Pacific Rise. They were caught by a baited trap at the hydrothermal vent site Oasis ( 17 degrees 25.38' S, 113 degrees 12.29' W) at 2586 m. The new genus differs from all of the 48 known ophidiid genera by its thick skin, posteriorly placed and enlarged kidneys, broad head, and 4 lateral lines. The most similar genera are Benthocometes and Petrotyx having a blunt snout, one basibranchial tooth patch, granular teeth, and no free pectoral fin rays. Remarks on the ecology of the new species are based on analysis of video documents taken in situ by a submarine Nautile.

Local, regional, and global policies to manage protect and restore our oceans and coasts call for the inclusion of ecosystem services (ES) in policy-relevant research. Marine and coastal ES and the associated benefits to humans are usually assessed, quantified, and mapped at the ecosystem level to inform policy and decision-making. Yet those benefits may reach humans beyond the provisioning ecosystem, at the regional or even global level. Current efforts to map ES generated by a single ecosystem rarely consider the distribution of benefits beyond the ecosystem itself, especially at the regional or global level. In this article, we elaborate on the concept of "extra-local" ES to refer to those ES generating benefits that are enjoyed far from the providing ecosystem, focusing on the marine environment. We emphasize the spatial dimension of the different components of the ES provision framework and apply the proposed conceptual framework to food provision and climate regulation ES provided by marine and coastal ecosystems. We present the different extents of the mapping outputs generated by the ecosystem-based vs. the extra-local mapping approach and discuss practical and conceptual challenges of the approach. Lack of relevant ES mapping methodologies and lack of data appeared to be the most crucial bottlenecks in applying the extra-local approach for marine and coastal ES. We urge for more applications of the proposed framework that can improve marine and coastal ES assessments help fill in data gaps and generate more robust data. Such assessments could better inform marine and coastal policies, especially those linked to equal attribution of benefits, compensation schemes and poverty alleviation.

The mineral phase of shell repair in the Manila clam Venerupis philippinarum affected by brown ring disease (BRD) was characterised at various scales and at various stages of shell repair by confocal Raman microspectrometry and scanning electron microscopy. Spherulitic and quadrangular aragonite microstructures associated with polyene pigments were clearly observed. Von Kossa staining showed that at the beginning of shell repair, hemocytes are filled with insoluble calcium carbonate salts in all fluids and then are transported toward the extrapallial fluids and the repair sites. Our analyses suggest that after a Vibrio tapetis attack and BRD deposit some clams rapidly cover the deposit, resulting in a modification in the microstructure, which could be produced by the participation of both the mantle and hemocytes.

Of the several bacterial diseases which may result from consumption of shellfish, those caused by marine bacteria of the genus Vibrio are the most abundant. In the United States, up to 10,000 non-fatal cases per year are estimated to be caused by the various members of this genus. More than 95% of all deaths in the United States which result from seafood consumption are caused by a single bacterium, Vibrio vulnificus. The bacterium is a normal inhabitant of estuarine waters, and occurs naturally in especially high numbers in molluscan shellfish. Infections following consuption of raw or undercooked shellfish, especially oysters, result in fatality rates of over 60%. Because most oysters in the United States are transported large distances before marketing, the possibility of temperature abuse of oysters as a factor in the epidemiology of this disease was investigated. Oysters (Crassostrea virginica) were allowed to take up cells of . vulnificus (CVD713) which had been added with algal cells. Following uptake, the live, shellstock oysters were placed at temperatures of 0.5, 5, 10, 17 and 22 degree C and maintained at those temperature for up to 10 days. At intervals, groups of five oysters were removed and assayed for the number of V. vulnificus cells present. Strain CVD713 contains the transposon, which carries genes for kanamycin resistance and alkaline phosphatase production. These markers permit significant selectivity of this strain from other normal flora bacteria, as well as differentiation from other kanamycin resistant cells that may be present. Temperature studies demonstrated that the transposon was stable at all investigation temperatures (Figure 1). Results indicated that, regardless of storage temperature, the number of V. vulnificus cells present in shellstock oysters decreased gradually with time, with the greatest decreases occurring at the higher temperatures (Figure 2). A similar result was seen when a 1000-fold lower number of cells were initially present in the oysters (Figure 4). No significant differences in cell survival were noted between opaque (encapsulated) cells (Figure 2) and translucent (non encapsulated) cells (Figure 6) of V. vulnificus. Similar results were obtained when an identical study was carried out employing a strain of V. cholerae harboring this transposon (data not shown). In contrast to the results observed when the storage studies were conducted on shellstock oysters, a rapid and dramatic decrease inV. vulnificus cell survival was observed at all temperatures when oysters were shucked prior to storage (Figure 7). Our results suggest that temperature abuse may not be a major factor in the epidemiology of infections by V. vulnificus. However, storage of V. vulnificus at low temperatures does not appear to significantly reduce the populations of this human pathogen.