Drivers for genetic structure at different geographic scales for Pacific red snapper (Lutjanus peru) and yellow snapper (Lutjanus argentiventris) in the tropical eastern Pacific

Abstract

The tropical eastern Pacific (TEP) is a highly dynamic region and a model system to study how habitat discontinuities affect the distribution of shorefishes, particularly for species that display ontogenetic habitat shifts, including snappers (Lutjanidae). To evaluate the genetic structure of the Pacific red snapper (Lutjanus peru) and the yellow snapper (Lutjanus argentiventris) throughout their distribution range along the TEP, 13 and 11 microsatellite loci were analysed, respectively. The genetic diversity of L. peru (N = 446) and L. argentiventris (N = 170) was evaluated in 10 and 5 localities, respectively, showing slightly higher but non-significant values in the Gulf of California for both species. The genetic structure analysis identified the presence of significant genetic structure in both species, but the locations of the identified barriers for the gene flow differed between species. The principal driver for the genetic structure at large scales >2500 km was isolation by distance. At smaller scales (<250 km), the habitat discontinuity for juveniles and adults and the environmental differences throughout the distribution range represented potential barriers to gene flow between populations for both species.

Genomic assessment reveals signal of adaptive selection in populations of the Spotted rose snapper Lutjanus guttatus from the Tropical Eastern Pacific

“… Sunde et al (2022) evaluated the potential that of microsatellites vs SNP data for detecting genetic structure and calculating genetic diversity; they concluded that microsatellite markers are better for characterizing genetic diversity while SNP data are better for detecting genetic structure. This conclusion could be corroborated by the differences in the heterozygosity estimates using microsatellites in L. peru (global H e = 0.811) and L. argentiventris (global H e = 0.757) ( Reguera-Rouzaud et al, 2021 ), as well as our estimates using SNPs (global H e = 0.097 for NL and H e = 0.102 for OL). Notwithstanding the weaknesses of the SNPs for the assessment of genetic diversity, we cannot discard inbreeding to explain the deficit of heterozygotes observed in the present work as has been stated in the brook charr Salvenilus fontinalis ( Castric et al, 2002 ).…”

“…It is also the first study to detect evidence of local adaptation with loci under selection (OL). Levels of overall genetic diversity observed in the localities using the NL and OL datasets ( H O = 0.073 and H O = 0.061, respectively, Table 1 ) were lower than the reported for other TEP marine organisms using microsatellite data ( García-De León et al, 2018 ; Reguera-Rouzaud et al, 2021 ), but they are comparable with values obtained using genomic data. This is the case of the genus Jasus ( J. cavereorum H O = 0.012 and J. paulensis H O = 0.087) ( Silva et al, 2021 ), Symphodus tinca , S. ocellatus ( Torrado et al, 2020 ), and for the freshwater species Esox lucius ( Sunde et al, 2022 ).…”

“…The apparent absence of physical barriers to gene flow in the ocean realm has prompted the idea that most marine species are panmictic ( Rocha-Olivares & Sandoval-Castillo, 2003 ; Munguia-Vega et al, 2018 ; Hernández-Álvarez et al, 2020 ). Large effective population sizes, a long pelagic larval phase or habitat preference have been some of the possible explanations for the lack of genetic structure in marine species ( Palmerín-Serrano et al, 2021 ; Reguera-Rouzaud et al, 2021 ). However, oceanographic conditions and habitat characteristics have recently been linked to genetic structure in marine species ( Weeks, 2017 ; Torrado et al, 2020 ).…”

“…The circulation pattern in the Gulf of Panama is influenced by The Intertropical Convergence Zone (ITCZ) ( Forsbergh, 1969 ), generates the alternation between cyclic and anticyclic gyres ( Monreal Gómez, Salas de león & Aldeco Ramírez, 1999 ), producing a coastal current that flows toward the south ( Strub & James, 2002 ). The patterns of circulation as well as oceanographic conditions such as temperature have been considered the possible explanation for the restricted exchange of individuals among the regions and with the north of the TEP ( García-De León et al, 2018 ; Sandoval-Huerta et al, 2019 ; Reguera-Rouzaud et al, 2021 ). However, oceanic circulation facilitates gene flow through dispersion of larval stages between populations within the Gulf of Panama ( e.g.…”

“…However, this differed from a study on L. peru using microsatellite markers, which found very low but significant levels of population structure in the southern Gulf of California ( Munguia-Vega et al, 2018 ). Another study using genetic markers with fast evolution rates detected genetic differences at the population level in L. peru and L. argentiventris throughout the TEP, where a combination of isolation by distance patterns (IBD) and oceanographic factors were responsible of the genetic structure observed ( Reguera-Rouzaud et al, 2021 ).…”