The St. Lawrence Estuary is known as a summer foraging area for several species of marine mammals, including several species of rorquals. Among these is the blue whale, which feeds almost exclusively on euphausiids. Therefore, the abundance, distribution and local density of krill should logically be a strong explanatory variable for the distribution of blue whales. However little is known about the spatial association of blue whales with the aggregation dynamics of krill in eastern Canada. Six years of acoustic surveys, conducted in August from 2009 to 2014, were undertaken to study the medium- and small-scale distribution of krill within the northwestern Gulf of St. Lawrence and estuary. The data shows a mosaic of the maximum annual density of arctic krill (T. raschii) made from these surveys. McQuinn, I.H., Gosselin, J.-F., Bourassa, M.-N., Mosnier, A., St-Pierre, J.-F., Plourde, S., Lesage, V., Raymond, A. 2016. The spatial association of blue whales (Balaenoptera musculus) with krill patches (Thysanoessa spp. and Meganyctiphanes norvegica) in the estuary and northwestern Gulf of St. Lawrence. DFO Can. Sci. Advis. Sec. Res. Doc. 2016/104. iv + 19 p.

Krill is a generic name for crustaceans of the order Euphausiids, most of which are known to be Thysanoessa raschii and Meganyctiphanes norvegica in eastern Canada. Krill is an important food resource for many marine mammals, in particular the blue whale. The maps show the points of high krill concentration per month from April to November. Each point gives the number of years of high aggregation probability (6 to 10 years). The data were produced from a mathematical model developed in Plourde et al. 2016. The model has allowed to calculate the probability of meeting a strong aggregation of krill over a period of 10 years. High krill aggregations are defined as the 95th percentile of predicted biomass in 10 x 10 km cells covering the Estuary and Gulf of St. Lawrence. Additional Information Plourde, S., Lehoux, C., McQuinn, I.H., and Lesage, V. (2016). Describing krill distribution in the western North Atlantic using statistical habitat models. DFO Can. Sci. Advis. Sec. Res. Doc. 2016/nnn. vi + xx p. Plourde, S., McQuinn, I.H., Lesage, V., Lehoux, C., Joly, P., Bourassa, M-N. in prep. Spatial distribution of krill in eastern Canadian waters: a climatological approach based on historical plankton net and acoustic data. The data are incomplete upstream of Pointe-des-Monts because of the lack of water height anomalies in the area (variable being used to predict aggregations of krill). A less number of years with a high aggregation of krill is thus represented but that should not be interpreted as a less favorable zone compared to areas East of Pointe-des-Monts.

Region(s) of distribution of Gelatinous Seasnail (Liparis fabricii) Krøyer, 1847 in the Arctic as digitized for U.S. Geological Survey Scientific Investigations Report 2016-5038. For details on the project and purpose, see the report at https://doi.org/10.3133/sir20165038. Complete metadata for the collection of species datasets is in the metadata document "Dataset_for_Alaska_Marine_Fish_Ecology_Catalog.xml" at https://doi.org/10.5066/F7M61HD7. Source(s) for this digitized data layer are listed in the metadata Process Steps section. Note that the original source may show an extended area; some datasets were limited to the published map boundary. Distributions of marine fishes are shown in adjacent Arctic seas where reliable data are available. The data were clipped to show only the marine distribution areas although some species also may have an inland presence.

Kernel density estimation (KDE) utilizes spatially explicit data to model the distribution of a variable of interest. It is a simple non-parametric neighbour-based smoothing function that relies on few assumptions about the structure of the observed data. It has been used in ecology to identify hotspots, that is, areas of relatively high biomass/abundance, and in 2010 was used by Fisheries and Oceans Canada to delineate significant concentrations of corals and sponges. The same approach has been used successfully in the Northwest Atlantic Fisheries Organization (NAFO) Regulatory Area. Here, we update the previous analyses with the catch records from up to 5 additional years of trawl survey data from Eastern Canada, including the Gulf of Saint Lawrence. We applied kernel density estimation to create a modelled biomass surface for each of sponges, small and large gorgonian corals, and sea pens, and applied an aerial expansion method to identify significant concentrations of these taxa. We compared our results to those obtained previously and provided maps of significant concentrations as well as point data co-ordinates for catches above the threshold values used to construct the significant area polygons. The borders of the polygons can be refined using knowledge of null catches and species distribution models of species presence/absence and/or biomass.

This dataset contains hydroacoustic results from the First International Biomass Experiment (FIBEX) cruise of the Nella Dan. This cruise is the first in a series of six cruises, performing a long term survey of krill and other zooplankton distribution and abundance. FIBEX was an international project, done in co-operation with Japan, South Africa and France. Fourteen transects were made by Australia off Antarctica in the Australian sector (Mawson to Davis region) and Prydz Bay in January to March 1981, covering a survey area of 1.09x10^6 square kilometers. Quantitative and geographic krill distribution, abundance, mean and variance of the krill weight density, and total krill biomass were obtained. The standing stock of krill for the Prydz Bay region was calculated at the second workshop to be approximately 1.3 million tonnes, or 1.6 million tonnes if extrapolated over the survey area of the SIBEX II cruise. Temperature, nutrient and salinty data were also obtained, as well as trawl results. Summary results are listed in the documentation. A scanned copy of the acoustics log book from the voyage is available for download from the provided URL.