Abstract
Pacific sardine (Sardinops sagax) are an economically important forage fish in the Northeast Pacific Ocean that undergo large changes in abundance over decadal scales and exhibit high individual variation in somatic growth. Past studies have suggested that somatic growth in Pacific sardine may be density-dependent and vary regionally in response to environmental conditions. We analyzed somatic growth in Pacific sardine off the U.S. Pacific Coast during the recent period of low abundance (2012–2021) and compared the results to those of previous studies to evaluate evidence of spatial or temporal variation in growth. Sampled fish (n = 3228) ranged in length from 30 to 291 mm SL and in age from 0 to 9 years and displayed high individual variation in length-at-age and age-at-length. Length-at-age data were best explained by the von Bertalanffy growth model, and sample distribution simulations showed the dataset to be robust and unbiased. Estimated growth parameters (L∞ = 243, K = 0.795, t0 = −0.638) were consistent with an opportunistic life history strategy characterized by rapid growth, early maturation, and a short lifespan. While the estimated growth rate (K) was higher than in a previous study conducted during a period of high abundance and indicated that growth may be density-dependent, the parameter estimates from the previous study were influenced by sample distribution bias. Similarly, differences in study region, season, collection method, aging methods, and other factors precluded any definitive conclusions on the source of reported differences in growth patterns among studies.