Latin American Journal of Aquatic Research, 37 (1) March 2009
Age and growth of the swordfish (Xiphias gladius Linnaeus, 1758) in the southeastern Pacific off Chile (2001)
The age and growth of swordfish (Xiphias gladius) in the southeastern Pacific off Chile were estimated for 511 males and 632 females using samples collected from longline fisheries in 2001. Lower jaw fork length (LJFL) measurements ranged from 100 to 265 cm for males and 116 to 289 cm for females. Age estimates were obtained using cross sections of the second anal fin ray. Both the monthly average marginal increment and the analysis of the edge type indicated periodicity in the formation of growth bands, with the hyaline band forming in the summer (December-March). The relationship between the ray radius and LJFL was nonlinear. The growth was modeled using standard and generalized Von Bertalanffy equations. Swordfish growth was best described by the standard equation, with the following parameters: L = 279 cm, K = 0.158, t0 = −2.65 for males, and L = 321 cm, K = 0.133, t0 = −2.46 for females. The analysis of growth curves revealed that females are significantly larger than males. A comparison of growth rates between different studies shows that swordfish in the southeastern Pacific off Chile grow faster than those from the northwestern Pacific (Taiwan), southwestern Pacific (Australia), and other regions (Atlantic Ocean, Mediterranean Sea), but their growth rates are very similar to those of the swordfish from the central North Pacific (Hawaii).
Author: José F. Cerna

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