Resumen del producto

Age estimation is a core element in every investigation focused on the rational exploitation of fishing resources. Although there are a number of studies that have estimated age in the blue marlin Makaira nigricans, the periodicity of annual growth-mark formation has not been assessed to validate such age estimates. Without this validation, age data cannot be reliably used for stock assessment. This investigation aims at validating the periodicity of annual growth-mark formation through semi-direct validation, one of the most widely used validation methods. For this purpose, observations and measurements were made in cross sections of the fourth dorsal fin spine in the blue marlin obtained from fish landed in 2005 and 2006 by the sport fishing fleet operating off Cabo San Lucas, Baja California Sur, Mexico. The analysis of the monthly percentage of opaque and translucent edges, as well as the marginal increase index, suggests that the formation of growth-marks (one opaque band followed by a translucent band) displays an annual periodicity and is related to sea surface temperature. A growth mark starts with the formation of an opaque band at the beginning of the year until August-September; in October, the translucent band starts to grow up to the beginning of the next year. Two additional biological indices are used to supplement our interpretation criteria.

Palabras clave: Growth; Blue marlin; validation

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