Glass sponge reefs (= hexactinellids), discovered off Canada’s western coast in 1987, remain a poorly known habitat with unique implications in the realms of paleobiology, fisheries management, biochemistry, and marine resource extraction. Ongoing research indicates that hexactinellid reefs exhibit highly variable growth forms between localized complexes within a broad distribution across the continental shelf in depths ranging from 35 to 290m. Yet, repeat multibeam echosounder surveys continue to reveal previously undetected sponge structures. This project aims to 1) describe the morphological characteristics of glass sponge reefs and 2) develop a novel sponge reef detection tool in GIS with minimal user input. Attributes were determined utilizing MBES bathymetry, backscatter, and derivatives (slope, GLCMs…) of known hexactinellid reefs from datasets provided by the Canadian Hydrographic Service. These were then used as filters in a GIS tool (scripted using Python), developed to calculate the necessary parameters from MBES data and provide a raster output of sponge reef sites. Results suggest that the detection tool is effective at detecting hexactinellid reefs with optimal detection features selected from ideal spatial resolutions; these are presented alongside a discussion on the accuracy and limitations of the tool, and its potential in detecting novel reef complexes. The GIS script developed here shows promise for generalized use for benthic habitat mapping, with implications beyond hexactinellid research.

Laws and regulations are omnipresent, extending their influence over the land, sea and rivers. They are often imposed by land administrators aiming to preserve ecosystems, to regulate land or marine activities and to identify law ownership. In such context, the latter is important to designate who is responsible for the application of different law and regulations that benefit human activities and the conservation of natural resources. This research project proposed a novel method to delineate the coastal boundary on the Saint-Lawrence Estuary based on morphometric analysis of the coastal area modelled by photogrammetric data acquired with low-cost UAV. The aimed precision is approximately 5 cm in planimetry and 10 cm in altimetry. A collection of different datasets was acquired in the St. Lawrence Upper Estuary in the summer of 2023, using a methodology adapted to the coastal environment. Preliminary tests of delimitation have considered the Geomorpon algorithm to classify the DTM. The project is still in progress and various other approaches will also be considered to delimit according to eco-geomorphological criteria and the tidal mark. Indeed, delineate properties boundaries based on high-water mark and coastline boundary consists of an intricate task, since it necessarily need to ally different morphometric analysis with legal analysis. A challenging factor to delineate properties on the Saint-Lawrence Estuary area is that the law and regulations are highly variable, depending on the type of each coast. It results in a dynamic delimitation process of property involving ongoing refinement and adjustment, reflecting the complexity of the scientific investigation. The approach proposed by this research is a major contribution to land surveyors community and related geosciences scientific works related to coastal area.

The acquisition of geospatial data from mobile platforms, in both terrestrial and hydrographic contexts, has been made more accessible with the development and popularization of various platforms (e.g. aerial drones, hydrographic drones, land robots, cars) used for the installation of different sensors of a wide range of prices. In the hydrospatial context, the use of drone platforms for bathymetric surveys is becoming unavoidable for various applications, especially in coastal areas, lake environments, shallow waters or close to marine structures whose navigation poses a real risk to the safety of data acquisition vessels. In this context, the design and development of a low-cost surface hydrographic drone has been the subject of a project at Université Laval in partnership with Groupe Océan. With a versatile, low-cost platform, various geomatics professionals will be able to benefit from a hydrospatial platform for surveys in different contexts, including coastal erosion monitoring, inspection of marine structures, bathymetric surveys, auscultation of coastal infrastructure, etc. The platform developed, the Ocean REPER 1 (cf. Figure 1), is modular and allows the integration of different sensors for coastal data acquisition. The drone was developed over a period of five months, between May and October 2023, at a final cost of around $2,900 CAN. It weighs around 10.5kg. The platform developed includes a trajectory data acquisition system and a bathymetry acquisition system with a single beam echosounder. The Ocean REPER 1 is an advantageous solution for acquiring hydrospatial data in a variety of contexts, especially for shallow, restricted-access lakes. In addition to its modular and portable nature, the platform has an autonomy of a few hours, and its electric propulsion system ensures that pollution of waterways is avoided, while minimizing the noise caused by the motors of the platform.