@article{fdi:010092154,
  title = {{B}ottom depth carving the pelagic spatial organisation in large marine ecosystem : the case of {N}orth {W}est {A}frica},
  author = {{M}ouget, {A}. and {B}rehmer, {P}atrice and {J}eyid, {M}. {A}. and {P}errot, {Y}annick and {D}iogoul, {N}. and {S}idibeh, {M}. and {M}amza, {K}. and {A}cou, {A}. and {S}arr{\'e}, {A}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}his study aimed to examine the spatial organization of pelagic communities within the water column along a horizontal gradient extending from the coast to the offshore area, categorized into three zones : inshore, offshore, and transition. {U}sing fisheries acoustics, a total of 29 000 nautical miles of acoustic transects collected during 14 annual standardized surveys were analyzed using two complementary acoustic methods : (i) extraction of sound scattering layers ({SSL}) and (ii) echointegration ({EI}) across the entire water column, both horizontally and vertically averaged. {T}he results revealed significant differences between the three bathymetric areas based on {SSL} and {EI} descriptors, with micro-nektonic communities in the transition area exhibiting intermediate characteristics between those in the inshore and offshore areas. {T}he relative abundance of micro-nektonic communities decreased from shallow coastal areas to deep offshore areas, with a mean {S}v from echointegration of -66.43, -74.39 and -73.65 d{B} for inshore, transition and offshore, respectively. {T}he inshore area is different from the transition and offshore areas, which is confirmed by diel vertical migration ({DVM}) analyze through vertical profiles. {A}ll areas exhibited classic {DVM} type {I}; however, offshore and transition areas also presented unexpected {DVM}s of type {II}, i.e., organisms descend deeper during the night, displaying distinct vertical profiles compared to the inshore area. {T}his suggests that the functional and specific composition of pelagic micronektonic communities differed between inshore and offshore areas, indicating that organisms adjust their responses to their environment. {O}ver two decades, the three bathymetric areas showed a significant increase in pelagic relative biomass and variation in {SSL} spatial structure. {T}he number of {SSL}s significantly increase, from 0.97 to 1.05 inshore, from 1.75 to 2.25 in the transition area and from 2.2 to 2.7 offshore. {N}evertheless, micronektonic communities reacted differently to interannual changes depending on the bathymetric areas, such as the minimal depth of the shallowest {SSL}. {F}luctuations in {SSL} descriptors were highlighted over the study period, which may be related to multi-decadal oscillations in the {A}tlantic {O}cean.},
  keywords = {{S}ound scattering layer ; {B}athymetry ; {D}iel vertical migration ; {P}elagic structuration ; {I}nterannual trends ; {ATLANTIQUE} ; {AFRIQUE} ; {ZONE} {TROPICALE}},
  booktitle = {},
  journal = {{C}ontinental {S}helf {R}esearch},
  volume = {285},
  numero = {},
  pages = {105372 [15 p.]},
  ISSN = {0278-4343},
  year = {2025},
  DOI = {10.1016/j.csr.2024.105372},
  URL = {https://www.documentation.ird.fr/hor/fdi:010092154},
}