Ecological patterns and processes occur at a myriad of spatial and temporal scales. Determining the appropriate scale(s) to collect and analyze data depends on the phenomena being studied and no one scale is appropriate for all of these. Knowing relevant measurement scales avoids the risk of presenting results that are merely a function of measurement scale rather than those relevant to actual ecological processes. Attribution of patterns to ecological processes requires a means to measure and evaluate these patterns. We present a standardized method to determine relevant spatial scales of fish-habitat associations observed from linear transect data on juvenile haddock (Melanogrammus aeglefinus), collected from six sites on the Scotian Shelf, off Canada's eastern coast. The survey data came from a large spatial scale research project undertaken by Fisheries and Oceans Canada to investigate spatial distribution of demersal fish in relation to seabed habitat in 2002 and 2003. We examined the relationship between two elements of this extensive dataset - the "towcam" video survey of demersal fish, and the interpreted surficial geology maps derived from sidescan sonar. We used the data from these surveys (48 towcam survey transect lines; 6 study sites, 2 5-km transect lines per site, day and night surveys per line, in each of 2 years = 240 km of transects), superimposed on the interpreted surficial geology layer collected at the same time. The resolution of the observations (similar to 2.5 m) facilitated a detailed examination of the spatial scales of ju -venile haddock association with seabed habitat. This was achieved using a "coarse-graining" approach, which we applied by summarizing fish abundance and seabed habitat proportions across bin sizes starting at 5 m and progressively doubling to 640 m. We tallied significant correlations by bin size to observe patterns in fish-habitat associations as a function of measurement scale, for each age group and diel period. We found that Juvenile haddock-seabed associations deteriorated at the grain limits marking the range of spatial scaling relevant for this phenomenon. We present a robust approach for quantifying appropriate scales of aggregations across linear transects which can serve as an important tool for basing observations to describe ecological patterns in space.

The Atlantic cod (Gadus morhua) stocks in the Newfoundland-Labrador Shelves (NL) and Barents Sea (BS) ecosystems have shown divergent trajectories over the last 40 years. Both stocks experienced either an important decline (BS) or a collapse (NL) in the mid-1980s and early 1990s, respectively. After these population reductions, the BS stock quickly rebounded and it is currently at record high levels, while the NL stock, despite showing some improvement since the mid-2000s, remains at low levels. Fishing and environmental conditions are known to be important drivers of cod dynamics in both ecosystems, especially the availability of high energy prey like capelin (Mallotus villosus), however, the question of how different or similar these two stocks truly are remains. Could, for example, the NL cod stock rebuild if presented to conditions like the ones experienced by BS cod? To explore such questions, we developed a simple biomass dynamic model for cod using a bioenergetic-allometric approach. This model includes fisheries catches and capelin availability as external drivers and was implemented for both ecosystems. Despite the contrasting trends, the model produced very good fits, and showed some remarkably similar estimated parameters in both systems. We explored these similarities by (a) performing the thought experiment of transferring cod stocks between ecosystems by switching estimated key parameters between models and comparing the output, and (b) implementing an integrated model architecture which allowed fitting common parameters for both stocks to evaluate the similarity of key vital rates. Our results indicate that cod trajectories in NL and BS can be reliably described using simple bioenergetic-allometric arguments, fishery catches, and capelin availability. Model parameters that encapsulate intrinsic vital rates were not significantly different between stocks. This indicates that NL and BS cod stocks are biologically similar, and that the differences in their trajectories are driven by the ecosystem context in which these stocks are embedded, and suggests that the NL stock would be expected to rebuild if enough capelin were available. This also indicates that capelin status and trend should be an important consideration for effective management of these cod stocks.

This report summarizes fish community trends for the Flemish Cap (NAFO Div. 3M) based on European Union summer trawl research vessel surveys between 1988 and 2018. Species were classified into eight functional groups and trends were described using biomass indices, biomass and abundance anomalies, and fish size (Biomass/Abundance Ratio) anomalies. In 2003, a replacement of the research vessel allowed extending the depth coverage of the survey from 700m to 1400m. The vessel change had an impact on survey catchability, so to account for it conversion factors were applied. Considering the change in depth coverage, trends were examined for 1988-2018 with data up to 700m, and for 2004-2018 with data up to 1400m. Fish community trends were similar between the two datasets, but the analyses including deeper waters showed a comparatively higher levels of benthivores, reflecting the changes in community structure with depth. Generally speaking, trends in average fish size as tracked by the Biomass/Abundance Ratio appeared driven by recruitment, where general declines in abundance and absences of good recruitments got reflected in increases of this ratio. Biomass of plankpiscivores (mostly Sebastes sp.) experienced a sharp increase in the early 2000s but then returned to levels comparable to the 1990s. Piscivores biomass showed a strong decline in the early 1990s due to the collapse of cod but has since shown signs of recovery. Shellfish, driven by northern shrimp, saw a sustained increase in biomass from the early 1990s until 2002, when started a decline that has persisted until 2018. The biomass of large benthivores decline in the late 1990s and remains low to this date.

Understanding seabed properties is increasingly important to support policy in the marine environment. Such knowledge can be gained from diverse methods, ranging from more traditional expert-interpretations of acoustic and ground-truth data, to maps resulting from fully quantitative analyses of acoustic data. This study directly compares surficial geology maps created through expert-interpretations to near-nadir acoustic backscatter data from two frequencies (38kHz and 120kHz) collected using single beam echosounders (SBES) for two 5×1km study areas on the Scotian Shelf, Canada. Statistical methods were used to analyze and classify both single and dual-frequency acoustic backscatter for comparisons. In particular, spatial scaling of acoustic backscatter responses and acoustic classes created using acoustic seabed classification (ASC) is compared between frequencies and to interpreted sediment units (ISUs) which make up surficial geology maps produced by experts. Seabed morphology layers were included in an ASC approach to reflect the morphological components included in the interpreted geological maps. Results confirmed that higher frequencies and coarser grain sizes generally produced higher backscatter, while more heterogeneous and rougher seabeds produced variable backscatter. Differing acoustic responses within similar substrate units suggest fundamental seabed variations not reflected in the geological interpretations. Spatial scaling of sand and gravel substrates from 38kHz frequency were closer than the 120kHz frequency to the spatial scaling of the interpreted geological map. Variable grain size in the sediment volume and surface morphology are both presented as possible reasons for frequency differences. While both frequencies had similar general responses, differences in frequency responses of backscatter occurred at scales of tens to hundreds of meters. Results presented here emphasize the importance of multi-scale seabed mapping and additional information available from multi-frequency approaches.

Recently Nalcor announced the discovery of three newly defined hydrocarbon basins located primarily in deep water in the Labrador Sea, off the east coast of Newfoundland and Labrador, Canada. The basins are Henley, Chidley and Holton Basins and expanded the extent of the Hawke Basin. On behalf of Nalcor Energy, C-CORE recently completed the Offshore Newfoundland and Labrador Metocean Study which summarizes environmental conditions of these regions to support offshore petroleum exploration and development in the Labrador Sea and to outline the resource potential to the global oil and gas industry. Defining iceberg densities was one of the required tasks for the study. Among various environmental conditions, iceberg density is one of the most challenging parameter to define accurately both spatially and temporally. Aerial iceberg reconnaissance flight surveys provided by IIP (International Ice Patrol) and CIS (Canadian Ice Service) were studied, classified and analyzed to compute iceberg density (number of icebergs per square km). Only open water icebergs were considered for analysis because of the difficulty associated with reliably identifying icebergs in pack ice, which may lead to an underestimation of iceberg occurrence. Therefore, aerial reconnaissance data were compared with CIS pack ice charts to eliminate any possibility of iceberg sightings in pack ice being included in the analysis. Satellite radar data acquired using Envisat wide swath mode (WSM) imagery was also used for iceberg detections in order to provide full coverage of the study area. Again, sea ice was outlined in the imagery to ensure no targets in sea ice were counted. The WSM imagery provided a 400 km wide swath with an approximate radar resolution of 150 m, meaning smaller targets were not detected. In order to combine satellite radar data with aerial reconnaissance surveys a non-detection factor was calculated using a comparison of concurrent Envisat and aerial coverage to compensate for missed targets due to the coarser radar resolution. The resulting map of open water iceberg densities will provide a baseline for the region which shall be further refined through an on-going program using high-resolution Sentinel satellite data. Detailed descriptions of the analysis, procedures and results are presented in this paper. Areal density results of the newly defined basins are compared to the other frontier regions, where iceberg risks are higher.

Abstract GIS-based software has been developed under the PIRAM (Pipeline Ice RiskAssessment and Mitigation) program for performing pipeline routing and burialanalysis for protection against ice keel gouging. Results are presented for ahypothetical pipeline in the Canadian Beaufort Sea. A probabilistic pipelineburial analysis is incorporated that accounts for the influence of sub-gougesoil displacements. Ice gouge rates and geometry are based on repetitivemapping survey data.

Delineating spatial management units is a necessary element for implementing ecosystem approaches to fisheries management. This study aimed to define spatially coherent ecological units (ecoregions) on the Newfoundland-Labrador (NL) Shelves using both physical and biological data which can serve as the basis for defining spatial management units (e.g. “management ecosystems”). The methods used were similar to previous studies in the US Northeast Atlantic continental Shelf and the Canadian Scotian Shelf in order to maintain consistency and a degree of comparability between results. Datasets were analyzed and classified using principal components analysis and k-means clustering. The clustering results were mapped in order to examine spatial distributions of the clusters. Results indicated that the physical variables (bathymetry, primary production, sea surface temperature) dominated the principal component analysis (PCA) signal when included in the analysis. Five major clusters (NL Shelf, Grand Banks, Southeast Shoal, Continental Slope, and nearshore) were typically identified on the classified maps. However, results varied based on the different PCA runs used in the clustering exercise. Features characterized at different spatial scales became apparent in the results with the inclusion of coral datasets. Including corals into the analysis created “patches” on the resulting maps, while the exclusion of corals from the analysis resulted in smoother and more continuous representation of the clusters on the maps.

Existing acoustic technologies used for seabed mapping typically use only one acoustic frequency. There is a growing interest in the scientific community to combine various acoustic frequencies to improve the accuracy of seabed habitat maps produced using these technologies, as it is typically done in satellite remote sensing. Classifying and mapping seabed sediment types can be achieved using acoustic echo sounders as different sediment types absorb, reflect or scatter varying amounts of acoustic energy, which allow them to be differentiated. Such maps can indirectly be used to delineate the distribution of marine benthic habitats of demersal (bottom dwelling) fish species as these habitats are believed to be primarily determined by substrate type. Using multiple frequencies should improve seabed sediment classification, and therefore seabed habitat maps, because backscatter intensity, a measure of the intensity of acoustic energy scattered back towards the source, varies with frequency. Hence, the use of multiple frequencies is expected to add information, as lower acoustic frequencies penetrate the seafloor deeper and higher frequencies will detect smaller spatial features. This research investigates the benefit of combining multiple acoustic frequencies from a single beam echo sounder to directly improve the mapping of seabed sediments, and indirectly improve seabed habitat maps. Raw acoustic data from 38 kHz and 120 kHz frequencies have been processed to extract backscatter strength data from the returned acoustic energy received by the transducer. These processed data have then been used to derive information about seafloor sediment characteristics. GIS techniques were used to classify the backscatter data and the resulting classes are compared to existing interpreted surficial geological classes of the area. This paper presents preliminary results of the classification done using the two frequencies, compares it to the individual classifications performed by each frequency, and relates it to interpreted surficial geological classes.

This report utilizes a geographic information systems (GIS) modelling approach to simulate commercial groundfish trawling sponge by-catch in lieu of actual commercial observations within the confines of current management restrictions to fishing within the Northwest Atlantic Fisheries Organization Regulatory Area (e.g., coral and sponge closed areas). Simulated trawl start locations (1500) were generated by using an aggregated 2008-2009 groundfishing effort raster as a probability surface. This effort surface was also used to set a heading for each of the lines following the direction corresponding to the maximum sum of effort. Combined and standardized sponge bycatch data from the Spanish and Canadian research vessel trawls were used to create a by-catch sponge biomass surface. The model extracted the sponge biomass values to each line to calculate the total by-catch per line (kg). Artificially imposing a range of threshold values on simulated by-catch data showed very few simulated trawls (0.4%) would catch more than the 800 kg encounter threshold of sponge under current management conditions. The percentage of simulated trawls above the imposed range of threshold values does not start to increase quickly until the threshold was between ~30 and 50 kg. At 50kg of simulated by-catch, only 5.5% of simulated tows would be affected and could be easily avoided as the areas impacted are localized. If the current encounter threshold for sponges was reduced from 800 kg to between 30 and 50 kg per tow it is unlikely to have a large effect on the commercial fishery within the fishing footprint and would serve as a more effective sponge conservation measure in un-fished areas under an exploratory fishery.