Preliminary estimates of French deepwater fishery discards in the Northeast Atlantic Ocean

Abstract

French deepwater fish exploitation (500 m) began off the West coast of the British Isles in 1973. It further developed in the 1980s, and intensified in the 1990s. In 1997, the French fleet comprised 49 boats, and since 1995 has landed yearly about 19,500 t of deepwater fish species, of which, the grenadier Coryphaenoides rupestris (Macrouridae) has been the most abundant. Discard data were sampled on-board by observers on French high sea trawlers from 1995 to 1997. Eight species were identified as totally landed, 43 non-commercial species as totally discarded and only one, the grenadier, as both landed and discarded. The mean discarding rate by haul was 48.5% in weight, whereas the mean grenadier discarding rate was 21.2%; these rates increased with depth. Discard species composition and discard quantities varied with depth, and depended on the specific composition of the fish communities, species abundance and their length-frequency distribution. The latter, established for grenadier and Alepocephalus bairdii (Alepocephalidae), assumes a bathymetric ontogenic migration. Annual discards of the fishery accounted for about 17,500 t in 1996 and 1997, but the results are quite uncertain.

Black scabbardfish,Aphanopus carbo, in the northeast Atlantic: distribution and hypothetical migratory cycle

“…carbo is a bathypelagic species that has been found at depths from 200 m, in the northern section of the NE Atlantic (Nakamura and Parin 1993;Kelly et al 1998), to 2300 m around the Canary Islands (Pajuelo et al 2008), but is more frequent between 800 and 1800 m in mainland Portugal (Martins et al 1987), 800 and 1300 m in Madeira (MoralesNin and Sena-Carvalho 1996), and 400 and 1400 m off the west of the British Isles (Ehrich 1983;Allain et al 2003). Its distribution is mainly associated with steep slopes, underwater rises, and canyons to the west of Portugal and along the gentle 334 I.…”

Defining value per unit effort in mixed métier fisheries

“…The time reported actually spent fishing (fishing hours) has traditionally been used as the effort measure in the computation of per unit effort, including as the standard input for the calculation of commercial catch or landings per unit effort indices used to tune stock assessments (ICES, 2012). Fishing hours are also used as an auxiliary variable in raising discards to fleet and fishery level (Allain et al, 2003;Borges et al 2005). Tidd (2013) used fishing hours for nominal vessel landing rates (LPUE) believing, as was thought here, that management decisions based on effort measured in hours would provide a less crude measure which closely relates to actual fishing activity.…”

Benchmarking for data-limited fishery systems to support collaborative focus on solutions

“…2). The stock is commercially exploited by French deep-water trawlers to the west of the British Isles (Allain et al, 2003), bottom longliners off mainland Portugal (BordaloMachado and Figueiredo, 2009) and horizontally drifting longliners off Madeira . In recent years, some fishing has also been recorded in Faroese and Icelandic waters (ICES, 2012a), off the Canary Islands (Pajuelo et al, 2008) and off the Azores (Machete et al, 2011).…”