@article{fdi:010064091,
  title = {{S}easonal oceanography from physics to micronekton in the south-west {P}acific},
  author = {{M}enk{\`e}s, {C}hristophe and {A}llain, {V}. and {R}odier, {M}artine and {G}allois, {F}rancis and {L}ebourges {D}haussy, {A}nne and {H}unt, {B}. {P}. {V}. and {S}meti, {H}. and {P}agano, {M}arc and {J}osse, {E}rwan and {D}aroux, {A}. and {L}ehodey, {P}. and {S}enina, {I}. and {K}estenare, {E}lodie and {L}orrain, {A}nne and {N}icol, {S}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}una catches represent a major economic and food source in the {P}acific {O}cean, yet are highly variable. {T}his variability in tuna catches remains poorly explained. {T}he relationships between the distributions of tuna and their forage (micronekton) have been mostly derived from model estimates. {O}bservations of micronekton and other mid-trophic level organisms, and their link to regional oceanography, however are scarce and constitute an important gap in our knowledge and understanding of the dynamics of pelagic ecosystems. {T}o fill this gap, we conducted two multidisciplinary cruises ({N}ectalis1 and {N}ectalis2) in the {N}ew {C}aledonian {E}xclusive {E}conomic {Z}one ({EEZ}) at the southeastern edge the {C}oral {S}ea, in 2011 to characterize the oceanography of the region during the cool ({A}ugust) and the hot ({D}ecember) seasons. {T}he physical and biological environments were described by hydrology, nutrients and phytoplankton size structure and biomass. {Z}ooplankton biomass was estimated from net sampling and acoustics and micronecton was estimated from net sampling, the {SEAPODYM} ecosystem model, a dedicated echosounder and non-dedicated acoustics. {R}esults demonstrated that {N}ew {C}aledonia is located in an oligotrophic area characterized by low nutrient and low primary production which is dominated by a high percentage of picoplankton cyanobacteria {P}rochlorococcus ( >90%). {T}he area exhibits a large-scale north-south temperature and salinity gradient. {T}he northern area is influenced by the equatorial {W}arm {P}ool and the {S}outh {P}acific {C}onvergence {Z}one and is characterized by higher temperature, lower salinity, lower primary production and micronekton biomass. {T}he southern area is influenced by the {T}asman {S}ea and is characterized by cooler temperature, higher salinity, higher primary production and micronekton biomass. {T}he dynamic oceanography and the complex topography create a myriad of mesoscale features including eddies, inducing patchy structures in the ecosystem. {D}uring the cool season, a tight coupling existed between the ocean dynamics and primary production, while there was a stronger decoupling during the hot season. {T}here was little difference in the composition of mid-trophic level organisms (zooplankton and micronekton) between the two seasons. {T}his may be due to different turnover times and delays in the transmission of primary production to upper trophic levels. {E}xamination of various sampling gears for zooplankton and micronekton showed that net biomass estimates and acoustic-derived estimates compared reasonably well. {E}stimates of micronekton from net observations and the {SEAPODYM} model were in the same range. {T}he non-dedicated acoustics adequately reproduced trends observed in zooplankton from nets, but the acoustics could not differentiate between zooplankton and micronelcton and absolute biomasses could not be calculated. {U}nderstanding the impact of mesoscale features on higher trophic levels will require further investigation and patchiness induced by eddies raises the question of how to best sample highly dynamic areas via sea experiments.},
  keywords = {{Z}ooplankton ; {N}ekton ; {A}coustic data ; {O}ceanographic surveys ; {M}esoscale eddies ; {O}ligotrophic ; {P}rimary production ; {PACIFIQUE} {SUD} {OUEST} ; {NOUVELLE} {CALEDONIE}},
  booktitle = {{I}mpacts of climate on marine top predators},
  journal = {{D}eep-{S}ea {R}esearch {P}art {II} : {T}opical {S}tudies in {O}ceanography},
  volume = {113},
  numero = {{N}o sp{\'e}cial},
  pages = {125--144},
  ISSN = {0967-0645},
  year = {2015},
  DOI = {10.1016/j.dsr2.2014.10.026},
  URL = {https://www.documentation.ird.fr/hor/fdi:010064091},
}