Monitoring the recovery of exploited deep-water species

Several deep-water species have suffered stock collapse as a result of commercial exploitation. ICES has advised a zero catch for orange roughy since 2004 and for Portuguese dogfish and leafscale gulper shark since 2005. These species began to be exploited in the early 1990s, and by the end of the decade they had already declined strongly in abundance. Some of these deep-sea fisheries continue, and these species continue to be caught, albeit as un-recorded discards. Fisheries-independent surveys would provide a means to assess their current status and stock development into the future. This project will monitor the recovery of exploited deep-water species following the decline of the deep-water fisheries in Irish waters.

The data will be collected in 2019 and 2020 by extending the depth range of the existing Irish Anglerfish and Megrim Survey series, which takes place in the first quarter of the year and covers the continental shelf up to 1000m. In order to obtain additional information on the selected deep-water species, the sampling depth on this survey needs to be expanded to at least 1500m. It is estimated that three days of additional days-at-sea will be required to complete the additional sampling.

The proposed approach is much more cost-effective than a stand-alone deep-water survey. The costs will be greatly reduced in terms of mobilising and demobilising the fishing gear and scientific equipment (typically 2 days per survey) and steaming time (typically 3 or 4 days for a deep-water survey). Additionally the risk of downtime due to weather or mechanical problems can be managed more efficiently on longer surveys. Marine Scotland has conducted a deep-water trawl survey most years since 1998. The Marine Institute extended this into Irish waters during the years 2006 to 2009. The renewed Irish sampling will again be closely coordinated with Marine Scotland