Persistence and variation in the distribution of bottom-trawl fish assemblages over the Flemish Cap

Abstract

The aim of this study is to test the variability of the assemblages defined in the Flemish Cap area. Data from 951 bottom hauls were analysed, covering depths between 126 and 740 m in the years 1995-2002. The fish fauna in Flemish Cap appears distributed in a persistent structural zonation defined in three assemblages. The first three factors of a Principal Component Analysis explained the 78.4% of the variance in distribution species, and they are consistent with the results of a cluster analysis. The three characteristic assemblages show a temporal persistence, but some changes appear in this period, for instance: displacements of the assemblages limits towards shallower waters, and some changes in relative position of the dominant species in each assemblage. These changes can be related with the constant decrease of the biomass of the main demersal fish species like Atlantic cod and American plaice. The species of Genus Sebastes appear as dominant fish species in the area.

Persistence and Variation on the Groundfish Assemblages on the Southern Grand Banks (NAFO Divisions 3NO): 2002-2011

“…For the general zonation pattern, five groups (Shallow, Intermediate and Deep) were identified. Even if our study analysed a mayor deep range boundaries and species composition were similar to those found in the previous studies in this area (Gomes et al, 1992) and in Flemish Cap (González-Troncoso et al, 2006). Cope and Haltuch (2012) also found persistence of assemblages through time in the west coast of U.S. even under fishing pressure and variable environmental conditions that suggests predictable relationships between species.…”

“…In the area of the Grand Banks of Newfoundland, different fish assemblages at depths from 40 to 500 m have been described by Gomes et al (1992). Similar fish assemblages were also defined by Paz and Casas (1996) and González-Troncoso et al (2006) in Flemish Cap. Although bathymetric ranges in those studies were different and dramatic changes in abundance and biomass of species caused changes in dominant species of assemblages, we observed a persistence in the main features of the assemblages over the time.…”

“…4). -Troncoso et al (2006) and Paz and Casas (1996) found a strictly shallow distribution for American plaice, Atlantic cod and wolffish in Flemish Cap. This is consistent with our results.…”

“…Mahon and Smith (1989) identified ten offshore assemblages of relatively similar species composition on the Scotian Shelf and Bay of Fundy, from 1970 to 1981; in the Flemish Cap (NAFO Div. 3M) three main assemblages were identified (Paz and Casas, 1996;González-Troncoso et al, 2006); Villagarcía (1995) studied the structure and distribution of demersal fish assemblages on the Northeast Newfoundland and Labrador Shelf; Gomes et al (1992) found six assemblages over 16 years (1971)(1972)(1973)(1974)(1975)(1976)(1977)(1978)(1979)(1980)(1981)(1982)(1984)(1985)(1986)(1987) on the Grand Banks of Newfoundland.…”

Marine epibenthic functional diversity on Flemish Cap (north‐west Atlantic)—Identifying trait responses to the environment and mapping ecosystem functions

“…The complex bottom currents in the area (Kenchington et al, ) indicate that retention can be quite high in some areas near bottom but that there is a rapid movement of water at the surface reaching velocities of >20 cm/s. Therefore, we cannot be confident that the high level of functional diversity found in the currently closed areas is sufficient to maintain ecosystem processes over the whole of Flemish Cap and in particular, in the shallower areas, where no closure is in place and different benthic and fish communities exist (González‐Troncoso, Paz, & Cardoso, ; Murillo, Serrano, et al, ).…”