A new study published in Nature has revealed serious declines in deep water species targeted for commercial fishing in the Northwest Atlantic. The study examined population trends in five species of deep water fish along the continental slope in the Atlantic waters of Canada caught in research trawl surveys between the period 1978 and 1994. Of those studied, two species – the roundnose grenadier and the onion-eye or roughhead grenadier – are commercially valuable. The remaining three species – blue hake, spiny eel and spinytail skate – are taken as bycatch in other fisheries, primarily the deep-water trawl fisheries for Greenland halibut and redfish.
The study found declines in these species ranging from 87% to 98% in the 17-year period examined – equivalent to approximately one generation in the life-span of these long lived species. In the case of roundnose grenadier and roughhead grenadier, additional information enabled the study to examine a 26 year period, 1978 – 2003, which put the decline at 99.6% for the roundnose grenadier and 93.3% for roughhead grenadier. Both of these species are caught within Canadian waters and on the high seas by vessels fishing in the Northwest Atlantic. According to data available from the Northwest Atlantic Fisheries Organization (NAFO), in 2003 the majority of these two species were caught by bottom trawl vessels operating on the high seas in the NAFO area, with the Spanish trawl fleet reportedly taking 4,597 tons – approximately 80% of the overall reported catch of roundnose and roughhead grenadier combined in the whole of the Northwest Atlantic (both inside EEZs and on the high seas). Political Advisor to the Deep Sea Conservation Coalition, Matthew Gianni said, “The declines in these species are extraordinary. Given the low fecundity and slow reproduction of the species it is not likely that they will recover to pre-1978 levels for possibly hundreds of years, if at all, especially considering that continued deep-sea bottom trawl fishing on the high seas of the Northwest Atlantic will inevitably continue to catch and deplete these species.” The study was undertaken by Jennifer Devine, Krista Baker and Richard Haedrich at Memorial University in St John’s, Newfoundland, Canada. The authors concluded that the steep rate of decline qualifies these species as “critically endangered” according to IUCN criteria. Roundnose grenadier and roughhead grenadier are extensively fished in the Northeast Atlantic Ocean as well. According to UN FAO data, in 2003 the Spanish high seas bottom trawl fleet accounted for approximately 60% of the catch of roundnose grenadier in the Northeast Atlantic as a whole (again, including catches from both inside EEZs and on the high seas). Both species are likely to be equally vulnerable to depletion in the Northeast Atlantic as are the populations in the Northwest Atlantic studied in the Nature report. The International Council for the Exploration of the Seas in 2005 called for a complete overhaul of the management of deep-sea fisheries in the Northeast Atlantic because of the vulnerability of deep-sea species to fishing pressure; unfortunately, the ICES recommendation was rejected by the European Union and other governments in the region. Matthew Gianni said, “Once again we see compelling scientific evidence for an immediate time out on high seas bottom trawling and a complete rethink of fisheries for deep-sea species. Nothing else will protect species being pushed to very low levels, including the brink of extinction. What we are doing to deep ocean species and ecosystems now may never be undone, and while it may already be too late for some species, it is not too late to take action now to protect what remains.”