Phylogeography and historical demography of the Pacific Sierra mackerel (Scomberomorus sierra) in the Eastern Pacific

Abstract

BackgroundTesting connectivity among populations of exploited marine fish is a main concern for the development of conservation strategies. Even though marine species are often considered to display low levels of population structure, barriers to dispersal found in the marine realm may restrict gene flow and cause genetic divergence of populations. The Pacific Sierra mackerel (Scomberomorus sierra) is a pelagic fish species distributed throughout the tropical and subtropical waters of the eastern Pacific. Seasonal spawning in different areas across the species range, as well as a limited dispersal, may result in a population genetic structure. Identification of genetically discrete units is important in the proper conservation of the fishery.ResultsSamples collected from the Eastern Pacific, including the areas of main abundance of the species, presented high levels of mtDNA genetic diversity and a highly significant divergence. At least two genetically discrete groups were detected in the northern (Sinaloa) and central areas (Oaxaca and Chiapas) of the species range, exhibiting slight genetic differences with respect to the samples collected in the southern region (Peru), together with a "chaotic genetic patchiness" pattern of differentiation and no evidence of isolation by distance. Historical demographic parameters supported the occurrence of past population expansions, whereas the divergence times between populations coincided with the occurrence of glacial maxima some 220 000 years ago.ConclusionsThe population genetic structure detected for the Pacific Sierra mackerel is associated with a limited dispersal between the main abundance areas that are usually linked to the spawning sites of the species. Population expansions have coincided with glacial-interglacial episodes in the Pleistocene, but they may also be related to the increase in the SST and with upwelling areas in the EEP since the early Pleistocene.

Contrasting colonization patterns of black mangrove (Avicennia germinans (L.) L.) gene pools along the Mexican coasts

“…Genetic patterns similar to those described in this work (stronger structure along the Pacific coast than the Atlantic) have been documented for other species, particularly in marine fishes with both demersal and pelagic habits (demersal: Bernardi, Findley, & Rocha‐Olivares, ; Garber, Tringali, & Stuck, ; Heist & Gold, ; Landínez‐García, Ospina‐Guerrero, Rodríguez‐Castro, Arango, & Márquez, ; Munguia‐Vega et al., ; Pruett, Saillant, & Gold, , pelagic: Bernardi et al., ; Broughton, Stewart, & Gold, ; López, Alcocer, & Jaimes, ; Pacheco‐Almanzar, Ramírez‐Saad, Velázquez‐Aragón, Serrato, & Ibáñez, ). This suggests that marine currents are important drivers of genetic structure, independent of the species’ biological traits.…”

Spatial and temporal genetic homogeneity of the Monterey Spanish mackerel,Scomberomorus concolor, in the Gulf of California

“…However, as expected for the mtCyt-b gene characterized by a lower mutational rate, a notably lower nucleotide diversity ( π  = 0.0048) was observed than reported for the mtDNA-CR of other Scomberomorus species ( S. sierra π  = 0.0195, Domínguez-López, Uribe-Alcocer & Díaz-Jaimes, 2010; S. niphonius π  = 0.0236, Shui et al, 2009 and S. commerson π  = 0.0380, Hoolihan, Anandh & Van Herwerden, 2006). All these studies have reported genetic homogeneity for distant populations where high population size and gene flow have been argued to explain the lack of population divergence.…”

“…For the mtCyt-b , a high haplotype diversity ( h  = 0.940) was observed similar to those of congeneric species based on mtDNA-CR sequences (Pacific sierra S. sierra h  = 0.997, Domínguez-López, Uribe-Alcocer & Díaz-Jaimes, 2010; the Japanese Spanish mackerel S. niphonius h  = 0.996, Shui et al, 2009 and the narrow-barred Spanish mackerel Scomberomorus commerson h  = 0.986, Hoolihan, Anandh & Van Herwerden, 2006). However, as expected for the mtCyt-b gene characterized by a lower mutational rate, a notably lower nucleotide diversity ( π  = 0.0048) was observed than reported for the mtDNA-CR of other Scomberomorus species ( S. sierra π  = 0.0195, Domínguez-López, Uribe-Alcocer & Díaz-Jaimes, 2010; S. niphonius π  = 0.0236, Shui et al, 2009 and S. commerson π  = 0.0380, Hoolihan, Anandh & Van Herwerden, 2006).…”

Genomic Differentiation and Demographic Histories of Atlantic and Indo-Pacific Yellowfin Tuna (Thunnus albacares) Populations

“…The demographic history, particularly when estimated using the faster human mutation rate, appears to be influenced by climatic changes related to Pleistocene glaciation cycles, as shown previously using the same method for the killer whale (Moura et al. 2014), but also for another member of the family Scombridae (the Pacific Sierra mackerel) using mismatch distributions (López et al. 2010).…”