Distribution of Scopoli's shearwater (Calonectris diomedea) in the Mediterranean Sea during the summer season Distance sampling surveys are extensively used to estimate the abundance of wide-ranging species but are prone to detection biases. This may be particularly acute for strip-transect protocols, which assume perfect detection. We examined this assumption by quantifying the detection probability of a declining seabird (Scopoli’s shearwater, Calonectris diomedea), with particular attention to time-of-day and observation conditions at sea. We found detection probability was negatively affected by sun glare but positively by cloud cover and considerably dropped during mid-day hours due to circadian changes in behaviour (reduced detectability while resting). This result urges for systematically assessing and correcting detection bias when using strip-transect data to derive abundance information. Here, we did so by building a detection-corrected presence-absence ensemble model and combining it with a compilation of colony sizes and locations. A Monte-Carlo simulation ensured uncertainty propagation within and across data sources. The corrected abundance map showed shearwaters were largely prevalent in the central Mediterranean, Tunisia hosting most of the population both at sea and at colonies (45% of the global population; 79% of breeding pairs). This first accurate map is an essential conservation tool, emphasizing the importance of transnational actions for such species, that know no political boundaries.

A metier in the Fisheries Information System is a fishing practice defined by a fishing gear and a target species. They are used for statistical purposes to evaluate fishing strategies and efforts.

The gear repository of the Fisheries Information System includes, on the one hand, the FAO fishing gears enriched with national specificities and, on the other hand, the sampling gears used during the fisheries surveys conducted by Ifremer and its partners.

The scientific species repository of the Fisheries Information System lists the species observed during fishing campaigns or within the framework of the observations of collection programmes (ObsVentes, ObsMer, Campaigns, etc.).

For some commercial species, coefficients called live weight equivalents allow the live weight of the fish to be calculated from the weight recorded on landing, or from the net weight of the various processed products prepared on board or in factories located on the coast.

The repository of commercially exploited species of interest in the Fisheries Information System is based on the FAO's ASFIS repository enriched with species of high commercial interest in France (metropolitan and overseas).

Size-weight relationships are specific to each scientific species and its environment. They allow the size of an individual to be determined from its weight or vice versa. These relationships are established statistically from a sample of individuals representative of the species.

The repository of location in the Fisheries Information System is divided into 3 categories: places on land, areas at sea and regulatory areas at sea. Each of these is organised hierarchically. There are 93 levels of places in Harmonie: a metadata sheet exists for each of them with, when it exists, a geographical layer.

Stocks (abundance and biomass) of the slipper limpet Crepidula fornicata Linnaeus, 1758 in the Pertuis Charentais shallows were estimated in 2011 and mapped (Sauriau et al., 2011). The influence of the estimate includes the Pertuis Breton, the eastern part Pertuis Antioch Fouras peninsula and the Bay of Marennes-Oléron where the latter earlier estimates are available. Contours and surface areas of the crepidula were previously determined by acoustic imaging performed aboard the VO/Haliotis in 2008 and 2009, interpreted and validated by spot sampling in 2009 (Curti, 2009). Sampling stocks of 2011 is based on a stratified random sample of 40 banks with a proportional distribution of sampling of 200 stations between banks. The listing for each crepidula bank stocks (abundance in millions, biomass in tonnes) both living and dead, these shells may provide support to potential new colonization.