TY - JOUR
T1 - Improving estimates of recruitment and catchability of jumbo squid Dosidicus gigas in the Gulf of California, Mexico
AU - Morales-Bojórquez, Enrique
AU - Hernández-Herrera, Agustín
AU - Cisneros-Mata, Miguel Ángel
AU - Nevárez-Martínez, Manuel O.
PY - 2008/12
Y1 - 2008/12
N2 - We analyzed the effect of outliers of the catch-per-unit effort on the catchability coefficient estimated by using a depletion model. When we used catch-per-unit effort in the Delury model, we observed a curve in the regression of depletion against time. When we then solved the model with a normal probability distribution, the catchability coefficient was poorly estimated. We improved the estimation of catchability using an algorithm that used a two-component-mixture probability distribution. The estimations for catchability (q) and recruitment (N0) were q = 0.41 × 10-3, N0 = 9.13 × 106, and the estimated likelihood was 2.65 × 104 using an algorithm of the normal probability distribution, whereas the estimations made using the algorithm of a two-component-mixture probability distribution were q = 0.23 × 10 -3, N0 = 18.07 × 106, and the estimated likelihood was 4.89 × 106. The maximum likelihood estimated with the mixture-distribution algorithm was greater than the maximum likelihood estimated with the normal-distribution algorithm. We believe the two-component-mixture probability distribution fit the data better than the normal probability distribution. From this we determined the consequences on management when overestimations or underestimations of catchability are estimated.
AB - We analyzed the effect of outliers of the catch-per-unit effort on the catchability coefficient estimated by using a depletion model. When we used catch-per-unit effort in the Delury model, we observed a curve in the regression of depletion against time. When we then solved the model with a normal probability distribution, the catchability coefficient was poorly estimated. We improved the estimation of catchability using an algorithm that used a two-component-mixture probability distribution. The estimations for catchability (q) and recruitment (N0) were q = 0.41 × 10-3, N0 = 9.13 × 106, and the estimated likelihood was 2.65 × 104 using an algorithm of the normal probability distribution, whereas the estimations made using the algorithm of a two-component-mixture probability distribution were q = 0.23 × 10 -3, N0 = 18.07 × 106, and the estimated likelihood was 4.89 × 106. The maximum likelihood estimated with the mixture-distribution algorithm was greater than the maximum likelihood estimated with the normal-distribution algorithm. We believe the two-component-mixture probability distribution fit the data better than the normal probability distribution. From this we determined the consequences on management when overestimations or underestimations of catchability are estimated.
KW - Catchability
KW - Depletion model
KW - Dosidicus gigas
KW - Management
KW - Outliers
KW - Recruitment
KW - Squid
UR - http://www.scopus.com/inward/record.url?scp=58149229476&partnerID=8YFLogxK
U2 - 10.2983/0730-8000-27.5.1233
DO - 10.2983/0730-8000-27.5.1233
M3 - Artículo
SN - 0730-8000
VL - 27
SP - 1233
EP - 1237
JO - Journal of Shellfish Research
JF - Journal of Shellfish Research
IS - 5
ER -