Allometry and Individual Growth of the Temperate Pacific Sardine (Sardinops sagax) Stock in the Southern California Current System

We analyzed individual growth and body mass allometry of the temperate stock of Sardinops sagax from samples collected on commercial fleet during 2005 to 2014 in the southern California Current System. Ages were estimated on otolith growth ring reading. Age (years) and standard length (SL; mm) data were fitted using four growth models: von Bertalanffy (VBM), Gompertz (GM), logistic (LM), and Schnute (SM) models. Parameters of each model were calculated by the maximum likelihood method using Akaike information criterion and Akaike's weight (WAIC(i)) to select the model with the greatest plausibility. Additionally, the interannual growth performance (phi') variation was described. Body mass allometry was established from the relationship between total body mass (TM; g) and standard length. The sardine samples ranged in size from 114 to 226 mm SL and in weight from 20 to 192 g TM; ages varied from 0.5 to 6.0 years. The allometric parameter (b) was estimated to be 3.155 (3.154-3.156), showing a hyper-allometry growth type. On the basis of raw data, we found that the LM model fit the original data better (WAIC(i) similar to 35%). When models were fitted to data bolstered with simulated values, the VBM model obtained the greatest weight (WAIC(i) = 60.9%), but the LM model had null plausibility. Consequently, we determined that the Pacific sardine growth pattern was best described by the VBM model, which appears to be more robust against biased data. The phi' showed interannual variation (2.13-2.51), with an average of phi' = 2.25. An apparent inverse relationship was observed between phi' and the Oceanic Nino Index (ONI) or the Pacific Decadal Oscillation (PDO) and the apparent positive relationship between Upwelling Index (UI) and phi'.

Automated summary

The study analyzed the individual growth and body mass allometry of the temperate stock of Sardinops sagax from 2005 to 2014 in the southern California Current System, as well as the interrelationship with environmental factors.