Biogeographical patterns of meso- and bathypelagic fish along a Northeastern Atlantic transect

Abstract

The influence of oceanographic variables on assemblages of meso- and bathypelagic fish was investigated along a Northeastern Atlantic Ocean transect (Cape Verde to the Bay of Biscay) during May 2019. Fish were collected using a mrozooplankton trawl during daylight hours at ten stations. Along the transect, 17 hydrographic stations were also performed with a CTD (Conductivity, Temperature, and Depth). A total of 130 fish taxa were identified. The dominant family was Gonostomatidae, with four species (Cyclothone braueri, Cyclothone microdon, Cyclothone pseudopallida, and Cyclothone pallida) being responsible of more than 78% of the total density. The most frequent species that appeared to be ubiquitous were C. braueri and C. pseudopallida, while Myctophidae was the most diverse family. Multivariate analyses revealed two clusters related with the latitudinal gradient. The fish community in the southern stations (25–37°N) was more diverse than in the northern stations (42–48°N). Temperature from 300 to 700 m depth explained 65% of variation in terms of density and 58% in terms of biomass, both statistically significant. The investigated variation in the deep-pelagic ecosystems on a large spatial scale gives essential information to ecosystem management approhes and marine spatial planning.

Acoustic micronektonic distribution and density is structured by macroscale oceanographic processes across 17–48° N latitudes in the North Atlantic Ocean

“…Temperature plays an important role in the distribution patterns of the marine species: temperature directly affects metabolic rates and thus have a direct impact on individual growth and reproduction 56 . During this cruise, a significant relationship between the fish assemblages and the temperature in the water column was also reported 21 . Fish communities showed a pattern of lower diversity in cold and more productive waters (from 42 to 48° N) and an increase in diversity in warmer conditions (from 27 to 37° N) 21 .…”

“…Fish communities showed a pattern of lower diversity in cold and more productive waters (from 42 to 48° N) and an increase in diversity in warmer conditions (from 27 to 37° N) 21 . In terms of densities, Cyclothone species were the main species for both fish communities collected in this cruise, while Benthosema glaciale , Maurolicus muelleri , and Xenodermichthys copei were only characteristic of colder waters (i.e., from 42 to 48° N) 21 .…”

“…The method assumes that at each depth, the observed temperature (T) and salinity (S) is a linear mixing between three different water types: where Ti and Si, i = 1:3, are the characterized temperature and salinity values of each water type, and x i are the fractions of each water type contributions. Descriptions of the hydrographic conditions and water masses in the northeast Atlantic can be found in several works, e.g., García-Seoane et al 21 , Bashmachnikov et al 33 and Valdés and Déniz-Gonzaáez 34 . In the study area, we identified five principal water types (Fig.…”

“…The main circulation patterns of the Northeastern Atlantic and how it affects the hydrographic conditions in the study area are detailed in 21 . Even though the Northeast Atlantic is one of the most studied areas (e.g., Magnússon 22 , Peña et al 23 , Ariza et al 24 , Blanluet et al 25 , Cascão et al 26 there still are major gaps (e.g., accurate estimations of biomass and knowledge on interaction between oceanography and micronekton biodiversity and biomass are needed) in the biology and ecology of the micronekton 6 .…”

Stranding of Mesopelagic Fishes in the Canary Islands

“…Moreover, this group is one of the most abundant marine vertebrates collected globally in mesopelagic waters [ 12 ]. Most mesopelagic fishes perform large diel vertical migrations (DVMs, [ 13 ]) from the deep-sea zone, where they remain during the day, to the shallower layers where they feed at night [ 14 , 15 , 16 ]. Thereby, they transport the ingested carbon in the upper productive layers to the deep waters [ 17 , 18 , 19 ], which is in turn of significance to the biogeochemistry of the ocean [ 3 , 20 , 21 , 22 ]…”