Genetic Diversity and Population Structure of Genypterus chilensis, a Commercial Benthic Marine Species of the South Pacific

Abstract

The red cusk-eel (Genypterus chilensis, Guichenot, 1848) is an iconic species in Chilean gastronomy, with a cultural significance that extends beyond its economic value, worthy of conservation. Despite the decline in fishery productivity across most of the distribution range for this species, little effort has been devoted to assessing stock management. In the present study, seven heterologous microsatellite loci (cmrGb3.8.1, cmrGb5.2B, cmrGb4.2A, cmrGb4.2B, cmrGb5.9, cmrGb4.11, and cmrGb2.6.1) were genotyped in a total of 153 individuals from four locations in central and southern Chile (30.5-37.6 • S), comprising ∼1,000 km of coastline. Five microsatellite loci were consistently amplified with a low frequency of null alleles (<2.5%). These markers showed high average heterozygosity (H O = 0.886 and H E = 0.884) and PIC (0.869). Significant genetic differentiation among locations (global F ST = 0.043, global D Jost = 0.252) suggested the presence of at least two genetic groups along the Chilean coast, with moderate levels of admixture between the two central populations (0.168 < Q mean < 0.822). The southern population showed no admixture with the central populations (Q mean = 0.985), less allelic richness and a small effective population size, indicating that urgent management measures must be developed for this fishery. The present study provides baseline information to assist fishery and aquaculture management and contribute to the recovery of declining populations.

Experimental tenacibaculosis infection in adult conger eel (Genypterus chilensis, Guichenot 1948) by immersion challenge with Tenacibaculum dicentrarchi

“…This species is abundant from southern Peru to the Chilean Patagonia (Vergara & George‐Nascimiento, 1982). Aspects associated with the farming of red conger eel have been studied in recent decades, including topics related to the development of farming technology, parasitism (George‐Nascimento et al., 2004), diet (Chong et al., 2006), the reproductive cycle (Chong & González, 2009) and genetic diversity and population structure (Córdova‐Alarcón et al., 2019; Jara‐Seguel et al., 2011). Particular focus has been given to the reproduction, growth, diet and genetics of red conger eels (Flores‐Kossack et al., 2020).…”

Molecular Inferences on Scomberomorus brasiliensis, From the Western South Atlantic, Based on Two Mitochondrial Genes

“…The results of the present study are consistent with those of Batista and Fabré (2001), who concluded that the coast of the Brazilian state of Maranhão is a part of the species' migratory circuit, which may exceed 300 nautical miles. Few physical barriers to dispersal exist in the ocean, and the dispersal of pelagic eggs and larvae on ocean currents, such as the Brazilian and North Brazil currents (see Rocha-Olivares et al, 2000;Broughton et al, 2002;Córdova-Alarcón et al, 2019), may also have contributed to the genetic homogeneity observed in the present study.…”

“…One reason for the divergence of the Cumana population may be its geographic location (Figure 1A), which is relatively isolated from the influence of adjacent marine environments, a situation that may limit its contact with other populations. Even so, fidelity to spawning sites, adaptations to specific oceanographic conditions, or feeding preferences may also be relevant here (Gold et al, 2010;López et al, 2010;Zhu et al, 2014;Córdova-Alarcón et al, 2019).…”

“…Given the fact of S. brasiliensis is one of the most harvested marine fish species on the Brazilian coast we suggest that population of the southwestern Atlantic may correspond to a single genetic stock, and should thus be treated as a unit. The genetic variability observed in the S. brasiliensis population sampled in the present study is important for the definition of effective conservation strategies, with the primary objective of mediating the decline of the population and guaranteeing the sustainability of this fishery resource (Ward, 2000;López et al, 2010;Souza-Shibatta et al, 2018;Córdova-Alarcón et al, 2019). Given this, further research on the S. brasiliensis populations should adopt a multi-locus approach integrating microsatellites, SNPs, and RADseq (see Siccha-Ramírez et al, 2018), which would complement the findings of the present study, based on two mtDNA loci.…”

Genetic differentiation and signatures of local adaptation revealed by RADseq for a highly-dispersive mud crab Scylla olivacea (Herbst, 1786) in the Sulu Sea

“…Genetic divergence associated with low effective population sizes have been previously reported for other marine taxa, e.g. red cusk-eel Genypterus chilensis due to high fishing pressure (Cordova-Alarcon et al, 2019), and population bottlenecks for Gadus morhua (Andreev et al, 2015) and Epinephelus marginatus (Buchholz-Sorensen and Vella, 2016). The possible causes of low effective population sizes in CRN and PPC are not known.…”