@article{fdi:010094259,
  title = {{D}rone photogrammetry reveals contrasting body conditions of dugongs across the {I}ndo-{P}acific},
  author = {{G}oudalier, {C}. and {M}ouillot, {D}. and {B}ernagou, {L}. and {B}oksmati, {T}. and {B}ristol, {C}. and {C}lark, {H}. and {H}erandarudewi, {S}. {M}. {C}. and {H}ocd{\'e}, {R}{\'e}gis and {K}oester, {A}. and {M}c{I}vor, {A}. {J}. and {N}air, {D}. and {N}andika, {M}. {R}. and {P}onnampalam, {L}. and {S}ahri, {A}. and {T}rotzuk, {E}. and {Z}aaba, {N}. {A}. and {M}annocci, {L}aura},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he monitoring of body condition, reflecting the state of individuals' energetic reserves, can provide early warning signals of population decline, facilitating prompt conservation actions. {H}owever, environmental and anthropogenic drivers of body condition are poorly known for rare and elusive marine mammal species over their entire ranges. {W}e assessed the global patterns and drivers of body condition for the endangered dugong ({D}ugong dugon) across its {I}ndo-{P}acific range. {T}o do so, we applied the body condition index ({BCI}) developed for the related manatee based on the ratio of umbilical girth (approximated as maximum width times pi), to straight body length measured in drone images. {T}o cover the entire dugong's range, we took advantage of drone footage published on social media. {C}ombined with footage from scientific surveys, social media footage provided body condition estimates for 272 individual dugongs across 18 countries. {D}espite small sample sizes relative to local population sizes, we found that dugong {BCI} was better, that is, individuals were 'plumper', in {N}ew {C}aledonia, the {U}nited {A}rab {E}mirates, {A}ustralia and {Q}atar where populations are the largest globally. {D}ugong {BCI} was comparatively poorer in countries hosting very small dugong populations such as {M}ozambique, suggesting a link between body condition and population size. {U}sing statistical models, we then investigated potential environmental and anthropogenic drivers of dugong {BCI}, while controlling for seasonal and individual effects. {T}he {BCI} decreased with human gravity, a variable integrating human pressures on tropical reefs, but increased with {GDP} per capita, indicating that economic wealth positively affects dugong energetic state. {T}he {BCI} also showed a dome-shaped relationship with marine protected area coverage, suggesting that extensive spatial protection is not sufficient to maintain dugongs in good state. {O}ur study provides the first assessment of dugong body condition through drone photogrammetry, underlining the value of this non-invasive, fast and low-cost approach for monitoring elusive marine mammals.},
  keywords = {aerial surveys ; conservation ; drones ; photogrammetry ; population ; monitoring ; sirenians ; {OCEAN} {INDIEN} ; {PACIFIQUE}},
  booktitle = {},
  journal = {{R}emote {S}ensing in {E}cology and {C}onservation},
  volume = {[{E}arly access]},
  numero = {},
  pages = {[18 p.]},
  year = {2025},
  DOI = {10.1002/rse2.70016},
  URL = {https://www.documentation.ird.fr/hor/fdi:010094259},
}