Hannah M. Murphy

Observational methods used in marine spatial monitoring of fishes and associated habitats: a review

Management areas are used in marine spatial planning to conserve biodiversity of marine ecosystems and to protect fish from fishing pressure. To evaluate the effectiveness of these protected areas, observational techniques are used to determine densities, sizes, biomass, habitat types and distribution of fish species in and around management areas. Two types of observational techniques are used in spatial monitoring: (1) fishery-independent techniques, which include underwater visual census (UVC), underwater video, remote sensing, acoustics, and experimental catch and effort data; and (2) fishery-dependent techniques, which include catch, effort and catch per unit effort data from commercial and recreational fisheries. This review summarises the applications, advantages, disadvantages and biases of each of these observational categories and highlights emerging technologies. The main finding from this review was that a combination of observational techniques, rather than a single method, was the most effective approach to marine spatial monitoring. For example, a combination of hydroacoustics for habitat mapping and UVC or video for fish surveys was one of the most cost-effective and efficient means of obtaining fish-habitat linkages and fish assemblage data. There are also emerging technologies that could increase the precision and efficiency of monitoring surveys. There is a need for continued development of non-intrusive technology for marine monitoring studies.

Migration patterns and putative spawning habitats of Atlantic halibut (Hippoglossus hippoglossus) in the Gulf of St. Lawrence revealed by geolocation of pop-up satellite archival tags

Arnault Le Bris,* Jonathan A. D. Fisher, Hannah M. Murphy, Peter S. Galbraith, Martin Castonguay, Timothy Loher, and Dominique Robert Centre for Fisheries Ecosystems Research, Fisheries and Marine Institute, Memorial University of Newfoundland, P.O. Box 4920, St. John’s, NL A1C 5R3, Canada Institut Maurice-Lamontagne, Pêches et Océans Canada, CP 1000, Mont-Joli, QC G5H 3Z4, Canada International Pacific Halibut Commission, 2320 West Commodore Way, Suite 300, Seattle, WA 98199-1287, USA *Corresponding author: tel: þ1 709 778 0482; fax þ1 709 778 0669; e-mail: arnault.lebris@mi.mun.ca. Present address: Northwest Atlantic Fisheries Centre, Fisheries and Oceans Canada, 80 East White Hills Road, PO Box 5667, St. John’s, NL A1C 5X1, Canada. Present address: Canada Research Chair in Fisheries Ecology, Institut des Sciences de la mer, Université du Québec a Rimouski, 310 allée des Ursulines, P.O. Box 3300, Rimouski, QC G5L 3A1, Canada.

Characterization of Depth Distributions, Temperature Associations, and Seasonal Migrations of Atlantic Halibut in the Gulf of St. Lawrence using Pop-Up Satellite Archival Tags

AbstractThe fishery for Atlantic Halibut Hippoglossus hippoglossus in the Gulf of St. Lawrence (Gulf) is currently experiencing its highest landings since the 1950s. However, the absence of information on adult habitat use has limited the development of new survey methodologies. The aim of this study was to use pop-up satellite archival tags on large (≥108-cm) halibut in the Gulf to provide data on seasonal temperature associations, depth distributions, and migrations. Twenty Atlantic Halibut were tagged in 2013 and 15 were tagged in 2015 at two different locations in the northern Gulf. Atlantic Halibut overwintered in the central and northern Gulf based on six tag pop-offs. In the winter in both studies, halibut were distributed at 160–440 m depth with a narrow temperature association of 5.5–6.5°C, which corresponded with the bathymetry and hydrography of the Gulf rather than the deeper and colder waters of the continental shelf where the southern stock occurs. Spawning rises were identified from the dep...