@inproceedings{fdi:010065857,
  title = {{E}valuating the efficacy of tropical tuna purse seiners in the {I}ndian {O}cean : first steps towards a measure of fishing effort},
  author = {{M}aufroy, {A}lexandra and {G}aertner, {D}aniel and {K}aplan, {D}avid and {B}ez, {N}icolas and {S}oto, {M}. and {A}ssan, {C}. and {L}ucas, {J}. and {C}hassot, {E}mmanuel},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he evaluation of the fishing effort exerted by purse seiners on tropical tuna requires a constant monitoring of the changes in individual fishing power of purse seiners due to changes in vessel characteristics, fishing gears or fishing strategies. {A}lso, since the 1990s, increasing numbers of drifting {F}ish {A}ggregating {D}evices have been used by this fleet. {A}s d{FAD}s contribute to a reduction of search times, traditional measures of fishing effort such as search time or fishing time are inappropriate. {H}ere, using logbook data from the {F}rench and the {S}panish purse seine fleets over 2003-2014, the effects of purse seiners' characteristics (length, the size of the wells, period of construction ) and their use of support vessels on the efficiency of purse seiners are analyzed with {GLM} models. 3 dimensions of the efficiency of purse seiners are analyzed: monthly catch rates, monthly frequency of fishing sets and monthly distance of fishing sets. {A}mong others, we find that support vessels contribute to an increase in catch rates (+10 tons per day) and in distance between fishing set. {I}n a second steps, the results of the {GLM} models are used to build 3 indexes of fishing effort that are compared to a simple monitoring of the number of {EU} purse seiners over 2003-2014. {O}urs result show that this simple index provide a biased image of the evolution of fishing effort for the purse seine fishery. {T}hough preliminary, they indicate that the main components of fishing power should be taken into account when measuring the fishing effort of tropical tuna purse seiners in the {I}ndian {O}cean.},
  keywords = {{OCEAN} {INDIEN}},
  numero = {{IOTC}-2015-{WPTT}17-14},
  pages = {12},
  booktitle = {17{\`e}me groupe de travail sur les thons tropicaux},
  year = {2015},
  URL = {https://www.documentation.ird.fr/hor/fdi:010065857},
}