@article{fdi:010070302,
  title = {{T}rophic position increases with thermocline depth in yellowfin and bigeye tuna across the {W}estern and {C}entral {P}acific {O}cean},
  author = {{H}oussard, {P}. and {L}orrain, {A}nne and {T}remblay-{B}oyer, {L}. and {A}llain, {V}. and {G}raham, {B}. {S}. and {M}enk{\`e}s, {C}hristophe and {P}ethybridge, {H}. and {C}outurier, {L}. {I}. {E}. and {P}oint, {D}avid and {L}eroy, {B}. and {R}eceveur, {A}. and {H}unt, {B}. {P}. {V}. and {V}ourey, {E}. and {B}onnet, {S}ophie and {R}odier, {M}artine and {R}aimbault, {P}. and {F}eunteun, {E}. and {K}uhnert, {P}. {M}. and {M}unaron, {J}ean-{M}arie and {L}ebreton, {B}. and {O}take, {T}. and {L}etourneur, {Y}.},
  editor = {},
  language = {{ENG}},
  abstract = {{E}stimates of trophic position are used to validate ecosystem models and understand food web structure. {A} consumer's trophic position can be estimated by the stable nitrogen isotope values (delta {N}-15) of its tissue, once the baseline isotopic variability has been accounted for. {O}ur study established the first data-driven baseline delta {N}-15 isoscape for the {W}estern and {C}entral {P}acific {O}cean using particulate organic matter. {B}ulk delta {N}-15 analysis on 1039 muscle tissue of bigeye and yellowfin tuna were conducted together with amino acid compound-specific delta {N}-15 analysis ({AA}-{CSIA}) on a subset of 21 samples. {B}oth particulate organic matter and tuna bulk delta {N}-15 values varied by more than 10 parts per thousand across the study area. {F}ine-scaled trophic position maps were constructed and revealed higher tuna trophic position (by similar to 1) in the southern latitudes compared to the equator. {AA}-{CSIA} confirmed these spatial patterns for bigeye and, to a lesser extent, yellowfin tuna. {U}sing generalized additive models, spatial variations of tuna trophic positions were mainly related to the depth of the 20 degrees {C} isotherm, a proxy for the thermocline behavior, with higher tuna trophic position estimates at greater thermocline depths. {W}e hypothesized that a deeper thermocline would increase tuna vertical habitat and access to mesopelagic prey of higher trophic position. {A}rchival tagging data further suggested that the vertical habitat of bigeye tuna was deeper in the southern latitudes than at the equator. {T}hese results suggest the importance of thermocline depth in influencing tropical tuna diet, which affects their vulnerability to fisheries, and may be altered by climate change.},
  keywords = {{N}itrogen isotopes ; {POM} ; {I}soscapes {B}igeye tuna ; {Y}ellowfin tuna ; {D}epth of the 20 degrees {C} isotherm ; {A}mino acid ; {C}ompound-specific isotope analysis ; {B}iochemical markers ; {PACIFIQUE} {OUEST} ; {PACIFIQUE} {CENTRE} ; {ZONE} {TROPICALE} ; {ZONE} {EQUATORIALE}},
  booktitle = {},
  journal = {{P}rogress in {O}ceanography},
  volume = {154},
  numero = {},
  pages = {49--63},
  ISSN = {0079-6611},
  year = {2017},
  DOI = {10.1016/j.pocean.2017.04.008},
  URL = {https://www.documentation.ird.fr/hor/fdi:010070302},
}