Estimation and temporal variability of gonadal maturity size of Horse mackerel (Scomber japonicus peruanus, Jordán & Hubb, 1925) in the Peruvian littoral

• Autores: Torrejón Magallanes, Edgar Josymar, Sánchez Espinoza, Javier, Mori Ponce, Julio, Bouchón Corrales, Marilú, Ñiquen Carranza, Miguel
• Formato: artículo
• Fecha de Publicación: 2017
• Institución: Universidad Nacional Mayor de San Marcos
• Repositorio: Revistas - Universidad Nacional Mayor de San Marcos
• Lenguaje: español
• OAI Identifier: oai:ojs.csi.unmsm:article/13741
• Enlace del recurso: https://revistasinvestigacion.unmsm.edu.pe/index.php/rpb/article/view/13741
• Nivel de acceso: acceso abierto
• Materia: Chub mackerel; size-at-gonad maturity; temporary changes; generalized linear mixed models; random effects.; Caballa; talla de madurez gonadal; cambios temporales; modelos lineales generalizados mixtos; efectos aleatorios

The values of size-at-gonad maturity (L50) of chub mackerel (Scomber japonicus peruanus) were estimated for the years 1994 – 2017 in the Peruvian littoral. The analysis was performed for the period November - March where the highest reproductive activity occurs. The proportion of mature females was ftted using a logistic binary model, through generalized linear mixed models (MLGM), which assumes random effects associated with the periods. The GLMM, with fixed effects estimated a L50 of 24.8 cm of fork length (FL) (24.69 cm - 24.9 cm), while with changes between periods, with random effects, L50 ranged between 20.4 cm and 27.0 cm FL. It was observed that an increase in temperature caused the decrease of the L50 in the years 1997 – 1999 and 2015 - 2016, which coincides with El Niño events. A positive correlation was found between the L50 and spawning biomass, so changes in L50 may be a density-dependent effect. There was no trend in the L50 series, so there would be no effect of the fishing mortality (F) on the L50. However, we think that the decrease in the L50 in relation to a low population density and mainly an increase in F should be given as a long-term effect and not in isolated events as our results showed.