@inproceedings{fdi:010063285,
  title = {{S}ome news approaches for standardizing tropical purse seiners {CPUE}s},
  author = {{K}atara, {I}. and {G}aertner, {D}aniel},
  editor = {},
  language = {{ENG}},
  abstract = {{I}ndices of {CPUE} are presented for skipjack tuna ({K}atsuwonus pelamis) for the {I}ndian {O}cean over the period 1980-2013. {T}he analysis was initiated under the framework of the {E}.{U}. research project {CECOFAD}, whose objectives are to enhance our understanding of fishing effort units and improve the accuracy of purse-seine {CPUE} estimates. {S}kipjack stock assessments mainly depend on abundance indices derived from purse-seine fleets, thus standardisation of purse seiner {CPUE}s for this species is a priority. {W}e follow a {CPUE} definition framework where three different types of {CPUE} are calculated to describe trends in number of schools, school detectability and catchability and school size. {CPUE} standardization is typically achieved with the development of {GLM} models; these estimates are often biased because the range of the fishing area changes from one year to the next. {W}e compare {CPUE} trends derived from conventional {GLM}s with trends based on {GLMM}s, where the spatial explanatory variables are treated as a random effect. {A}ccording to a definition, a variable is random when it constitutes only a part of the entire population: spatial variables can be considered random since each year fishing vessels sample only a part of the historically fished area. {E}xploratory analyses revealed issues of heterogeneity and autocorrelation, supporting the use of mixed models and the shift towards a {B}ayesian approach to {CPUE} standardization modeling. {O}ur analysis uses fishing sets targeting free swimming tuna schools for the {F}rench purse seiners operating in the western {I}ndian {O}cean. {F}uture work will address the problem of accounting for the major changes in purse seine fishing strategies and the implementation of new technology on board (mainly the use of {FAD} technology) under a {B}ayesian framework.},
  keywords = {{PECHE} {THONIERE} ; {SENNEUR} ; {CAPTURE} ; {EFFORT} {DE} {PECHE} ; {ESTIMATION} {DE} {STOCK} ; {MODELISATION} ; {ANALYSE} {STATISTIQUE} ; {OCEAN} {INDIEN}},
  numero = {{IOTC}-2014-{WPTT}16-16},
  pages = {16},
  booktitle = {16{\`e}me groupe de travail sur les thons tropicaux},
  year = {2014},
  URL = {https://www.documentation.ird.fr/hor/fdi:010063285},
}