@article{fdi:010060804,
  title = {{H}ow much do fish aggregating devices ({FAD}s) modify the floating object environment in the ocean ?},
  author = {{D}agorn, {L}aurent and {B}ez, {N}icolas and {F}auvel, {T}. and {W}alker, {E}.},
  editor = {},
  language = {{ENG}},
  abstract = {{N}atural floating objects (e.g., logs) have always been a component of the habitat of tropical tunas. {H}owever, the introduction of fish aggregating devices ({FAD}s) modifies this environment. {T}o assess the changes due to the deployment of {FAD}s, we compared the spatial distribution of natural and artificial floating objects ({FAD}s), using data from observers onboard tuna purse seine vessels in the {I}ndian {O}cean from {D}ecember 2006 to {D}ecember 2008. {A}lthough natural objects occur more commonly in waters south of 7 degrees {S} and {FAD}s are more common in waters north of 7 degrees {S}, all types of floating objects can be found everywhere. {U}sing different spatial scales (quadrats of size 1 degrees x1 degrees, 2 degrees x2 degrees, 5 degrees x5 degrees, and 10 degrees x10 degrees), we computed the proportion of {FAD}s observed in quadrats without natural objects. {T}he scale of 2 degrees x2 degrees quadrats represented a threshold: distributions of the two types of objects were different at scales smaller than this threshold. {T}he strongest change that has occurred since the introduction of {FAD}s (besides the increased catches) has been the dramatic increase in the total number of floating objects. {S}ince the introduction of {FAD}s, the number of objects has at least doubled everywhere (except in the {M}ozambique {C}hannel and {C}hagos) and in some areas (e.g., {S}omalia area) the multiplication factor has reached as high as 20 or 40. {O}ur study sets the ranges of values of key parameters of the floating object environment, which are crucial in the design of future experimental studies aimed at investigating the impacts of {FAD}s on the ecology of tunas.},
  keywords = {ecological trap ; fish aggregating devices ; floating objects ; {I}ndian {O}cean ; tuna ; {OCEAN} {INDIEN}},
  booktitle = {},
  journal = {{F}isheries {O}ceanography},
  volume = {22},
  numero = {3},
  pages = {147--153},
  ISSN = {1054-6006},
  year = {2013},
  DOI = {10.1111/fog.12014},
  URL = {https://www.documentation.ird.fr/hor/fdi:010060804},
}