@article{fdi:010077342,
  title = {{M}icronekton distributions and assemblages at two shallow seamounts of the south-western {I}ndian {O}cean : insights from acoustics and mesopelagic trawl data},
  author = {{A}nnasawmy, {P}. and {T}ernon, {J}ean-{F}ran{\c{c}}ois and {C}otel, {P}ascal and {C}herel, {Y}. and {R}omanov, {E}. {V}. and {R}oudaut, {G}ildas and {L}ebourges {D}haussy, {A}nne and {M}{\'e}nard, {F}r{\'e}d{\'e}ric and {M}arsac, {F}rancis},
  editor = {},
  language = {{ENG}},
  abstract = {{M}icronekton distributions and assemblages were investigated at two shallow seamounts of the south-western {I}ndian {O}cean using a combination of trawl data and a multi-frequency acoustic visualisation technique. {L}a {P}a rouse seamount (summit depth similar to 60 m) is located on the outskirts of the oligotrophic {I}ndian {S}outh {S}ubtropical {G}yre ({ISSG}) province with weak mesoscale activities and low primary productivity all year round. {T}he "{MAD}-{R}idge" seamount (thus termed in this study; similar to 240 m) is located in the productive {E}ast {A}frican {C}oastal ({EAFR}) province with high mesoscale activities to the south of {M}adagascar. {H}igher micronekton species richness was recorded at {MAD}-{R}idge compared to {L}a {P}erouse. {R}esulting productivity at {MAD}-{R}idge seamount was likely due to the action of mesoscale eddies advecting productivity and larvae from the {M}adagascar shelf rather than local dynamic processes such as {T}aylor column formation. {M}ean micronekton abundance/biomass, as estimated from mesopelagic trawl catches, were lower over the summit compared to the vicinity of the seamounts, due to net selectivity and catchability and depth gradient on micronekton assemblages. {M}ean acoustic densities in the night shallow scattering layer ({SSL}: 10-200 m) over the summit were not significantly different compared to the vicinity (within 14 nautical miles) of {MAD}-{R}idge. {A}t {L}a {P}erouse and {MAD}-{R}idge, the night and day {SSL} were dominated by common diel vertically migrant and non-migrant micronekton species respectively. {W}hile seamount-associated mesopelagic fishes such as {D}iaphus suborbitalis ({L}a {P}erouse and {MAD}-{R}idge) and {B}enthosema fibula= performed diel vertical migrations ({DVM}) along the seamounts' flanks, seamount-resident benthopelagic fishes, including {C}ookeolus japonicus ({MAD}-{R}idge), were aggregated over {MAD}-{R}idge summit. {B}efore sunrise, mid-water migrants initiated their vertical migration from the intermediate to the deep scattering layer ({DSL}, {L}a {P}erouse: 500-650 m; {MAD}-{R}idge: 400-700 m) or deeper. {D}uring sunrise, the other taxa contributing to the night {SSL} exhibited a series of vertical migration events from the surface to the {DSL} or deeper until all migrants have reached the {DSL} before daytime. {P}ossible mechanisms leading to the observed patterns in micronekton vertical and horizontal distributions are discussed. {T}his study contributes to a better understanding of how seamounts influence the {DVM}, horizontal distribution and community composition of micronekton and seamount-associated/resident species at two poorly studied shallow topographic features in the south-western {I}ndian {O}cean.},
  keywords = {{M}icronekton ; {S}eamount ; {S}outh-western {I}ndian {O}cean ; {A}coustics ; {S}eamount-associated fauna ; {OCEAN} {INDIEN}},
  booktitle = {},
  journal = {{P}rogress in {O}ceanography},
  volume = {178},
  numero = {},
  pages = {102161 [21 ]},
  ISSN = {0079-6611},
  year = {2019},
  DOI = {10.1016/j.pocean.2019.102161},
  URL = {https://www.documentation.ird.fr/hor/fdi:010077342},
}