@article{fdi:010086067, title = {{R}ich and underreported : first integrated assessment of the diversity of mesopelagic fishes in the {S}outhwestern {T}ropical {A}tlantic}, author = {{E}duardo, {L}. {N}. and {B}ertrand, {A}rnaud and {L}ucena-{F}redou, {F}. and {V}illarins, {B}. {T}. and {M}artins, {J}. {R}. and {A}fonso, {G}. {V}. {F}. and {P}ietsch, {T}. {W}. and {F}redou, {T}. and {D}i {D}ario, {F}. and {M}incarone, {M}. {M}.}, editor = {}, language = {{ENG}}, abstract = {{M}esopelagic fishes play critical ecological roles by sequestering carbon, recycling nutrients, and acting as a key trophic link between primary consumers and higher trophic levels. {T}hey are also an important food source for harvestable economically valuable fish stocks and a key link between shallow and deep-sea ecosystems. {D}espite their relevance, mesopelagic ecosystems are increasingly threatened by direct and indirect human activities while representing some of the largest and least understood environments on {E}arth. {T}he composition, diversity, and other aspects of the most basic biological features of numerous mesopelagic groups of fishes are still poorly known. {H}ere, we provide the first integrative study of the biodiversity of mesopelagic fishes of the southwestern {T}ropical {A}tlantic ({SWTA}), based on two expeditions in northeastern {B}razil in 2015 and 2017. {A} full list of mesopelagic fishes of the region is provided, including rare species and new records for the {B}razilian {E}xclusive {E}conomic {Z}one and the indication of potentially new species in groups such as the {S}tomiiformes and {B}eryciformes. {K}ey aspects of the diversity of mesopelagic fishes of the region were also assessed, considering different depth strata and diel periods. {A}t least 200 species, 130 genera, 56 families, and 22 orders of the {T}eleostei and one shark ({I}sistius brasiliensis, {D}alatiidae, {S}qualiformes) were recorded, including potentially eight new species (4%) and 50 (25%) new records for {B}razilian waters. {F}ive families accounted for 52% of the diversity, 88% of specimens collected, and 66% of the total biomass: {S}tomiidae (38 spp., 8% of specimens, 21% of biomass), {M}yctophidae (34 spp., 36%, 24%), {M}elamphaidae (11 spp., 2%, 7%), {S}ternoptychidae (9 spp., 26%, 10%), and {G}onostomatidae (7 spp., 16%, 4%). {D}uring the day, richness and diversity were higher at lower mesopelagic depths (500-1000 m), with contributions of typically bathypelagic species likely associated with seamounts and oceanic islands. {A}t night, richness and diversity increased at epipelagic depths, indicating the diel ascension of several species (e.g., myctophids and sternoptychids) that can endure temperature ranges of up to 25 degrees {C}. {I}nformation on the geographic distribution of several rare species worldwide is also provided.}, keywords = {deep-sea ; oceanic islands ; seamounts ; biodiversity ; {B}razil ; {F}ernando de {N}oronha {R}idge ; {BRESIL} ; {ATLANTIQUE} ; {FERNANDO} {DE} {NORONHA} ; {ATLANTIQUE} {SUD} {OUEST} ; {ZONE} {TROPICALE}}, booktitle = {}, journal = {{F}rontiers in {M}arine {S}cience}, volume = {9}, numero = {}, pages = {937154 [18 p.]}, year = {2022}, DOI = {10.3389/fmars.2022.937154}, URL = {https://www.documentation.ird.fr/hor/fdi:010086067}, }