Predictive models of the preferential distribution of demersal fish larvae in the southern part of the California Current

Abstract

<jats:p>Habitat characterization provides predictive information about the distribution of species and is useful for as­sessing habitat quality and population stability. Larval abundance of six frequent and abundant demersal species and the relationship of each with the environment were analysed through generalized additive models to determine their preferential distribution and predictive response to the environmental variables in the southern part of the California Current (25-31°N) between two periods of data collection: 1997-2000 and 2006-2010. Essentially, the main associated variables governing the distribution patterns were related to common and oceanographic characteristics of the water column (temperature and salinity at 50 m depth, dynamic height and degree of water column stratification); however, the set of variables and their ranges are usually species-specific. Species of northern distribution, Sebastes sp. and Citharichtys stigmaeus, were recorded mainly in newly emerged, relatively unstratified waters characterized by a shallow mixed layer and low temperatures. Low dynamic height values were the most significant predictor of larval distribution for Merluccius productus. Citharichthys xanthostigma and Symphurus atricaudus were widespread, distributed across the study area mainly in autumn in unstratified or stratified waters and at a shallow mixed layer. Particularly C. Xanthostigma and S. Lucioceps were related to high dynamic height val­ues, likely influenced by a coastal flow towards the pole, as evidenced by counter-currents.</jats:p>

Influence of oceanographic conditions on the body shape variability of Scomber japonicus larvae from the western coast of the Baja California Peninsula

“…Pacific chub mackerel larval distribution has been related to different oceanographic structures, such as cyclonic and anticyclonic eddies in the WCBCP (Anaya‐Godínez et al, 2017). These types of oceanographic structures can influence the transport and distribution of planktonic organisms (Anaya‐Godínez et al, 2017; Funes‐Rodríguez et al, 2015; Peiro‐Alcantar et al, 2020), and swimming speed could also be altered by their morphology (Axler et al, 2020). In fact, thermal variability also influences the segregation of morphotypes; fish larvae with slender heads mainly occur in cold periods and vice versa (Galeano‐Chavarria et al, 2020; Landaeta et al, 2019).…”

“…This region has a marked seasonal cycle that results from different mesoscale structures, such as eddies and meanders, during most of the year (Durazo et al, 2010; Soto‐Mardones et al, 2004). These structures are potentially responsible for planktonic transport and retention (Anaya‐Godínez et al, 2017; Funes‐Rodríguez et al, 2015; Peiro‐Alcantar et al, 2020). Although several studies have established a relationship between Pacific chub mackerel larval distributions and oceanographic conditions, their effect on body morphology is poorly understood.…”

Spatiotemporal patterns of variability in the abundance and distribution of winter-spawned pelagic juvenile rockfish in the California Current

“…The timing and intensity of upwelling events is linked to both the growth and survival of larval and early juvenile stages, as well as the transport and advection or retention of the same from spawning grounds. Larval stages of rockfish and other groundfish are often associated cooler and less saline water masses, and greater larval abundance tends to be associated with years of greater southward flow in the California Current [ 63 , 64 ]. However, years with strong upwelling can lead to advection of those larvae or later juvenile stages offshore, while years with dramatically reduced or delayed upwelling (for example 2005) are associated with lower productivity, leading to low survival and abundance, and potentially more inshore distributions of YOY, which may be less available to the trawl survey [ 65 , 66 ].…”