The 2005 Recovery Potential Assessment (RPA) for porbeagle shark (SSR 2005/043) stated that a shark-directed survey would be required if the directed fishery for porbeagle was to be resumed. The primary objective of a time series of shark surveys would be to monitor the status of the porbeagle population in response to recovery efforts, by providing a fishery-independent estimate of relative abundance and size composition. Survey estimates of abundance would be free of the constraints of using commercial catch rate as an index of abundance during periods of a spatially-contracted fishery, such as was documented in the fishery after 2000. Since the detailed population model described in the RPA provides an estimate of population abundance to 2005, a shark survey conducted in 2006 or 2007 could be calibrated against the most recent abundance estimate from the population model. Once that relationship is defined, subsequent surveys would be used to monitor changes in porbeagle population abundance, and thus track the population recovery. A secondary objective of the survey would be to monitor the population abundance and size composition of other shark populations, particularly blue shark and mako.

A dedicated shark survey using shark longline gear would have to be conducted each year for at least 2 years to provide a reasonable estimate of shark distribution and abundance. Subsequent surveys could be conducted at broader intervals, if desired. Longline gear would be fished throughout the water column, from surface to bottom and back to surface. The survey area would consist of about 50 stations distributed in a grid pattern across the Scotian Shelf, in the Gulf of St. Lawrence and off of southern Newfoundland.

The first shark survey was completed in June 2007.  The second survey was completed in July 2009, and is being compared with the results of the 2007 survey to determine if population recovery is underway.  The array of survey stations is shown below.