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Email the author (Login required) Sexual maturity effects on the relative growth of the central stock of northern anchovy Engraulis mordax (Clupeiformes: Engraulidae) off the west coast of Baja California, Mexico
Submited: 2025-09-23 21:26:05 | Published: 2026-06-30 22:44:53
DOI: https://doi.org/10.3856/vol54-issue3-fulltext-3538
Abstract
The objective of this study was to analyze the standard length-total weight (SL-WT) relationships of the central stock of northern anchovy (Engraulis mordax) off Baja California to determine its relative growth pattern (isometric or allometric) and its variation in relation to size at maturity. The length-weight relationship was determined by fitting somatic growth to the observed SL-WT data using a polyphasic model, segmented into two phases (stanzas), which estimates a stanza change length (SCL). Student's t-tests were used to assess the type of growth. Likewise, the SL at maturity (SL50) was estimated using a polyphasic model to compare and identify changes in relative growth. Females were more frequent in large sizes (>95 mm SL), whereas males dominated the smaller size classes in the sample. Growth exhibited significant allometry according to the polyphasic model, showing hyperallometric (b = 3.17) growth in the first stage and hypoallometric (b = 2.64) growth in the second. The SCL in relative growth was estimated at 97.51 mm for males and 99.03 mm for females. These values correspond to SL50 and also coincide with the minimum legal size (MLS = 100 mm SL) established as a management measure. The process of sexual maturity may be associated with changes in relative growth, suggesting that the energetic demands linked to reproductive function at the onset of adulthood influence somatic growth. The use of the polyphasic regression model represents a promising approach when information on sexual maturity is scarce, as SCL estimates can serve as a useful indicator of fish maturation.
