@article{fdi:010044209,
  title = {{P}atterns in the spatial distribution of {P}eruvian anchovy ({E}ngraulis ringens) revealed by spatially explicit fishing data},
  author = {{B}ertrand, {S}ophie and {D}iaz, {E}. and {L}engaigne, {M}athieu},
  editor = {},
  language = {{ENG}},
  abstract = {{P}eruvian anchovy ({E}ngraulis ringens) stock abundance is tightly driven by the high and unpredictable variability of the {H}umboldt {C}urrent {E}cosystem. {M}anagement of the fishery therefore cannot rely on mid- or long-term management policy alone but needs to be adaptive at relatively short time scales. {R}egular acoustic surveys are performed on the stock at intervals of 2 to 4 times a year, but there is a need for more time continuous monitoring indicators to ensure that management can respond at suitable time scales. {E}xisting literature suggests that spatially explicit data on the location of fishing activities could be used as a proxy for target stock distribution. {S}patially explicit commercial fishing data could therefore guide adaptive management decisions at shorter time scales than is possible through scientific stock surveys. {I}n this study we therefore aim to (1) estimate the position of fishing operations for the entire fleet of {P}eruvian anchovy purse-seiners using the {P}eruvian satellite vessel monitoring system ({VMS}), and (2) quantify the extent to which the distribution of purse-seine sets describes anchovy distribution. {T}o estimate fishing set positions from vessel tracks derived from {VMS} data we developed a methodology based on artificial neural networks ({ANN}) trained on a sample of fishing trips with known fishing set positions (exact fishing positions are known for approximately 1.5% of the fleet from an at-sea observer program). {T}he {ANN} correctly identified 83% of the real fishing sets and largely outperformed cornparative linear models. {T}his network is then used to forecast fishing operations for those trips where no observers were onboard. {T}o quantify the extent to which fishing set distribution was correlated to stock distribution we compared three metrics describing features of the distributions (the mean distance to the coast, the total area of distribution, and a clustering index) for concomitant acoustic survey observations and fishing set positions identified from {VMS}. {F}or two of these metrics (mean distance to the coast and clustering index), fishing and survey data were significantly correlated. {W}e conclude that the location of purse-seine fishing sets yields significant and valuable information on the distribution of the {P}eruvian anchovy stock and ultimately on its vulnerability to the fishery. {F}or example, a high concentration of sets in the near coastal zone could potentially be used as a warning signal of high levels of stock vulnerability and trigger appropriate management measures aimed at reducing fishing effort.},
  keywords = {{P}eruvian anchovy ; {F}ish distribution ; {V}essel monitoring system ({VMS}) ; {N}eural network ; {M}ultilayer perceptron ({MLP}) ; {F}ishing sets distribution ; {C}lustering index ; {P}urse-seine fleet},
  booktitle = {},
  journal = {{P}rogress in {O}ceanography},
  volume = {79},
  numero = {2-4},
  pages = {379--389},
  ISSN = {0079-6611},
  year = {2008},
  DOI = {10.1016/j.pocean.2008.10.009},
  URL = {https://www.documentation.ird.fr/hor/fdi:010044209},
}