Identificación de zonas propicias para el desarrollo larval de la macarela del Pacífico (Scomber japonicus) en la porción sur de la Corriente de California

Abstract

Abstract.-Larval size is considered as an important variable to understand the changes in larval development and identification of a suitable environment for larval growth and survivor. Larvae of the Pacific mackerel (Scomber japonicus) have a slow growth during the early stages of development (6-8 mm SL); subsequently, the growth rate increases, but the development depends mainly on the temperature and food. The aim of this study was to identify the areas and seasons favorable for larval development of S. japonicus, in relation to the sea surface temperature and the zooplankton biomass, off the west coast of the Baja California Peninsula (~25°-32°N) from 2006 to 2010. Larvae of the Pacific mackerel showed the greatest amplitude in their spatial distribution during spring, but with greater restricted abundance compared to Punta Eugenia (~28°N) during summer. Changes in its distribution were influenced by geostrophic flow and thermal variability. Linear regression analysis allowed to identify areas favorable for larvae development, with a lower development in spring, related to a narrow range of temperatures and levels of comparatively low zooplankton biomass. In contrast, during summer the largest increase in body height () was related to a wide range of temperatures, while its low variability (standard error) coincided with high levels of zooplankton biomass. It is considered that thermal conditions and food availability, favor an optimum larval development, particularly during the summer season.Key words: Pacific mackerel, fish larvae, isometric growth, suitable areas, California CurrentResumen.-El tamaño larval es una variable importante para entender los cambios en el desarrollo y la identificación de un entorno adecuado para el crecimiento y la supervivencia larval. Las larvas de la macarela del Pacífico (Scomber japonicus) presentan un lento crecimiento durante las primeras fases del desarrollo (6-8 mm de LE); posteriormente, la velocidad de crecimiento aumenta, pero el desarrollo depende principalmente de la temperatura y del alimento. El objetivo del presente trabajo fue identificar las zonas y temporadas propicias para el desarrollo larval de S. japonicus, en relación a la temperatura superficial del mar y la biomasa del zooplancton, frente a la costa occidental de la Península de Baja California (~25-32°N) del 2006 al 2010. Las larvas de la macarela del Pacífico mostraron la mayor amplitud en su distribución espacial en primavera, pero con mayor abundancia restringida frente a Punta Eugenia (~28°N) durante el verano. Los cambios en su distribución, estuvieron bajo la influencia del flujo geostrófico y la variabilidad térmica. El análisis de regresión lineal permitió identificar zonas propicias para el desarrollo de larvas, con un menor desarrollo en primavera, relacionado con un int ervalo estrecho de temperaturas y niveles de biomasas del zooplancton comparativamente bajos. En contraste, durante el verano el mayor incremento en la altura del cuerpo () fue relacionado con un amplio intervalo de tempe...

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

“…OA estimated for the analyzed larvae showed that only 10.30% of the observed morphological changes corresponded to changes associated with growth (allometry). These results are consistent with the isometric analysis performed by Anaya‐Godínez et al (2017) and similar to those observed in larvae of mesopelagic fish, such as myctophids Diogenichthys atlanticus (9.75%) and Diogenichthys laternatus (9.73%; Zavala‐Muñoz et al, 2019). In contrast, some cryptobenthic species change with habitat through their ontogeny (neritic to benthic) with higher OA: Myxodes viridis (Clinidae) 14.69% (Zavala‐Muñoz et al, 2016), Auchenionchus crinitus (Labrisomidae) between 19.30% and 29.92% (Landaeta et al, 2019), and Sicyases sanguineus (Gobiesocidae) 31.69% (Bernal‐Durán & Landaeta, 2017).…”

“…In addition, Magdalena Bay is considered an overlap zone for both groups (Gluyas‐Millán & Quiñónez‐Velázquez, 1996). Larval morphological differences are consistent with the other evidence of these stocks (Anaya‐Godínez et al, 2017).…”

“…Pacific chub mackerel enters the metamorphosis stage with sizes > 7 mm (Go et al, 2020; Hunter & Kimbrell, 1980). This suggests that the larger larvae (͞ x > 8 mm) and hydrodynamic shape observed in spring 2008 coincided with the greatest intensification of the flow due to the point effect in front of Punta Eugenia (28°N) (Anaya‐Godínez et al, 2017). These morphological changes could result in higher swimming speeds that may increase feeding success.…”

“…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).…”

“…Additionally, when temperature is <30°C, salinity does not have any significant effect on larval development (Wuenschel et al, 2004). On the other hand, relationships between morphological changes and zooplankton biomass were weak, despite a positive relationship between larval occurrence and comparatively high biomass values (Anaya‐Godínez et al, 2017). This discrepancy may be because high zooplankton biomass does not always indicate greater availability of edible prey for fish larvae (Axler et al, 2020).…”