A steep genetic cline in yellowtail rockfish, Sebastes flavidus, suggests regional isolation across the Cape Mendocino faunal break

2011 ◽  
Vol 68 (1) ◽  
pp. 89-104 ◽  
Author(s):  
Jon E. Hess ◽  
Russell D. Vetter ◽  
Paul Moran

As with all Sebastes species, yellowtail rockfish ( S. flavidus ) produce larvae with an extended pelagic juvenile phase that can be advected in coastal currents. While dispersal potential is high, previous research on population genetic characteristics of Sebastes species indicates that apparent realized dispersal can be much lower and can exhibit complex patterns of genetic structure. We assayed 812 bp of the mitochondrial cytochrome b gene and six microsatellite loci in ∼1000 yellowtail rockfish collected from 21 sites that span the species range from southern California to southeastern Alaska. An abrupt genetic cline near Cape Mendocino, California, splits the range into a northern and southern stock, and is highly concordant between our mitochondrial (FCT = 0.32, p ≪ 0.001) and microsatellite (FCT = 0.02, p ≪ 0.001) datasets. We show that this pattern may be due to a combination of physical (oceanographic or other barriers to larval dispersal), biological (habitat differences), and historical events. This study, and both intra- and inter-specific evidence from other marine species suggests Cape Mendocino demarcates two regions experiencing divergent evolutionary trajectories, and should be considered in management strategies.

2016 ◽  
Vol 73 (9) ◽  
pp. 2333-2341 ◽  
Author(s):  
Jennifer R. Ovenden ◽  
Bree J. Tillett ◽  
Michael Macbeth ◽  
Damien Broderick ◽  
Fiona Filardo ◽  
...  

Abstract We report population genetic structure and fine-scale recruitment processes for the scallop beds (Pecten fumatus) in Bass Strait and the eastern coastline of Tasmania in southern Australia. Conventional population pairwise FST analyses are compared with novel discriminant analysis of principal components (DAPC) to assess population genetic structure using allelic variation in 11 microsatellite loci. Fine-scale population connectivity was compared with oceanic features of the sampled area. Disjunct scallop beds were genetically distinct, but there was little population genetic structure between beds connected by tides and oceanic currents. To identify recruitment patterns among and within beds, pedigree analyses determined the distribution of parent–offspring and sibling relationships in the sampled populations. Beds in northeastern Bass Strait were genetically distinct to adjacent beds (FST 0.003–0.005) and may not contribute to wider recruitment based on biophysical models of larval movement. Unfortunately, pedigree analyses lacked power to further dissect fine-scale recruitment processes including self-recruitment. Our results support the management of disjunct populations as separate stocks and the protection of source populations among open water beds. The application of DAPC and parentage analyses in the current study provided valuable insight into their potential power to determine population connectivity in marine species with larval dispersal.


2013 ◽  
Vol 65 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Mirjana Ocokoljic ◽  
Dragica Vilotic ◽  
Mirjana Sijacic-Nikolic

The general population genetic characteristics of cultivated horse chestnut trees excelling in growth, phenotype characteristics, type of inflorescence, productivity and resistance to the leafminer Cameraria ohridella Deschka and Dimic were analyzed in Serbia. The analyzed population genetic parameters point to fundamental differences in the genetic structure among the cultivated populations in Serbia. The study shows the variability in all properties among the populations and inter-individual variability within the populations. The variability and differential characteristics were assessed using statistical parameters, taking into account the satisfactory reflection of the hereditary potential. The assessed differences in the vitality and evolution potential of different populations can determine the methods of horse chestnut gene pool collection, reconstruction and improvement.


2021 ◽  
Vol 8 ◽  
Author(s):  
Hudson T. Pinheiro ◽  
Jose A. C. C. Nunes ◽  
E. O. C. Coni ◽  
E. C. G. Almeida ◽  
C. L. S. Sampaio ◽  
...  

Overfishing is notorious for triggering population collapses and disrupting marine biological functioning worldwide. To counter such a threat, policy-makers have created and implemented multiple management strategies, but most were incapable to prevent the decline of several key species. Here, we discuss a new management strategy in force since June 2019 in Brazil that aims to deter the overfishing of parrotfish species of the genera Scarus and Sparisoma. This innovative strategy, here referred to as inverted management, allows the capture of endangered parrotfish species inside management areas, such as partially protected marine areas—MPAs, but bans it elsewhere. This initiative is supposed to be built in a partnership among the government, scientists, managers, and fishers. If implemented correctly, endangered species would recover in the much larger area outside MPAs, and fishers would benefit from the conservation-value of the scarce and valued product. However, to succeed, the strategy depends on the adoption of a series of challenging management rules that are not currently being enforced along an extensive coastline. So far, few MPAs have incorporated rules for endangered species in their management plan, and those that have done so have no plans or the means to enforce them. Therefore, fishing of endangered species is currently ongoing without any management or monitoring in the entire Brazilian coast. Concerned with the challenges to develop plans to recover populations of endangered species faced by Brazilian managers, we suggest wide communication and a ban on the fisheries until management plans are implemented. Additionally, we suggest that the effectiveness of the inverted management strategy for parrotfishes should be assessed before it’s applied to other endangered species.


Author(s):  
Г.И. Ельчинова ◽  
З.К. Гетоева ◽  
В.В. Кадышев ◽  
М.Ю. Джаджиева ◽  
Р.А. Зинченко

Генетико-эпидемиологическое обследование населения республики Северная Осетия-Алания проводится сотрудниками лаборатории генетической эпидемиологии ФГБНУ «МГНЦ». В рамках стандартного протокола исследования проводится изучение максимально возможного числа популяционно-генетических характеристик. На основании 27583 брачных записей проанализированы индекс эндогамии, интенсивность метисации и этническая брачная ассортативность в 8 районах Северной Осетии и г. Владикавказе. Выявлены различия этих брачно-миграционных характеристик между двумя субэтносами - иронцами и дигорцами. Дигорцы характеризуются более высокой эндогамностью и более низкой метисацией, чем иронцы. Genetic epidemiological study of the population of the North Ossetia-Alania Republic, Russia, is caring out by the Laboratory of Genetiс Epidemiology of Research Centre for Medical Genetics (Moscow, Russia).Within the framework of the standard protocol we study the maximum of possible population-genetic characteristics. Based on the 27583 marriage records, the index of endogamy, the intensity of metisation and ethnic marriage assortativness in 8 regions of North Ossetia and Vladikavkaz have been analyzed. The differences in the marriage and migration characteristics are revealed for two subethnoses: the Irons and the Digors. The Digors have a higher value of endogamy index and a lower metisation level than the Irons have.


Heredity ◽  
2020 ◽  
Vol 126 (1) ◽  
pp. 63-76
Author(s):  
Sarah M. Griffiths ◽  
Mark J. Butler ◽  
Donald C. Behringer ◽  
Thierry Pérez ◽  
Richard F. Preziosi

AbstractUnderstanding population genetic structure can help us to infer dispersal patterns, predict population resilience and design effective management strategies. For sessile species with limited dispersal, this is especially pertinent because genetic diversity and connectivity are key aspects of their resilience to environmental stressors. Here, we describe the population structure of Ircinia campana, a common Caribbean sponge subject to mass mortalities and disease. Microsatellites were used to genotype 440 individuals from 19 sites throughout the Greater Caribbean. We found strong genetic structure across the region, and significant isolation by distance across the Lesser Antilles, highlighting the influence of limited larval dispersal. We also observed spatial genetic structure patterns congruent with oceanography. This includes evidence of connectivity between sponges in the Florida Keys and the southeast coast of the United States (>700 km away) where the oceanographic environment is dominated by the strong Florida Current. Conversely, the population in southern Belize was strongly differentiated from all other sites, consistent with the presence of dispersal-limiting oceanographic features, including the Gulf of Honduras gyre. At smaller spatial scales (<100 km), sites showed heterogeneous patterns of low-level but significant genetic differentiation (chaotic genetic patchiness), indicative of temporal variability in recruitment or local selective pressures. Genetic diversity was similar across sites, but there was evidence of a genetic bottleneck at one site in Florida where past mass mortalities have occurred. These findings underscore the relationship between regional oceanography and weak larval dispersal in explaining population genetic patterns, and could inform conservation management of the species.


2012 ◽  
Vol 69 (3) ◽  
pp. 415-429 ◽  
Author(s):  
Denis Roy ◽  
Thomas R. Hurlbut ◽  
Daniel E. Ruzzante

Understanding the factors generating patterns of genetic diversity is critical to implementing robust conservation and management strategies for exploited marine species. Yet, often too little is known about population structure to properly tailor management schemes. Here we report evidence of substantial population structure in white hake ( Urophycis tenuis ) in the Northwest Atlantic, perhaps among the highest levels of population structure exhibited by a highly exploited, widely dispersed, long-lived marine fish. We show that depth plays a role in this extensive and temporally stable structure, which does not conform to previously established fisheries management units. Three genetically distinguishable populations were identified, where all straddle several management divisions and two (Southern Gulf of St. Lawrence and Scotian Shelf) overlap in their range, coexisting within a single division. The most highly exploited population in the Southern Gulf of St. Lawrence was also the most isolated and likely the smallest (genetically effective). This work shows that conservation and management priorities must include population structure and stability in establishing effective species recovery strategies.


2015 ◽  
Vol 282 (1812) ◽  
pp. 20151217 ◽  
Author(s):  
Luke Thomas ◽  
W. Jason Kennington ◽  
Michael Stat ◽  
Shaun P. Wilkinson ◽  
Johnathan T. Kool ◽  
...  

A detailed understanding of the genetic structure of populations and an accurate interpretation of processes driving contemporary patterns of gene flow are fundamental to successful spatial conservation management. The field of seascape genetics seeks to incorporate environmental variables and processes into analyses of population genetic data to improve our understanding of forces driving genetic divergence in the marine environment. Information about barriers to gene flow (such as ocean currents) is used to define a resistance surface to predict the spatial genetic structure of populations and explain deviations from the widely applied isolation-by-distance model. The majority of seascape approaches to date have been applied to linear coastal systems or at large spatial scales (more than 250 km), with very few applied to complex systems at regional spatial scales (less than 100 km). Here, we apply a seascape genetics approach to a peripheral population of the broadcast-spawning coral Acropora spicifera across the Houtman Abrolhos Islands, a high-latitude complex coral reef system off the central coast of Western Australia. We coupled population genetic data from a panel of microsatellite DNA markers with a biophysical dispersal model to test whether oceanographic processes could explain patterns of genetic divergence. We identified significant variation in allele frequencies over distances of less than 10 km, with significant differentiation occurring between adjacent sites but not between the most geographically distant ones. Recruitment probabilities between sites based on simulated larval dispersal were projected into a measure of resistance to connectivity that was significantly correlated with patterns of genetic divergence, demonstrating that patterns of spatial genetic structure are a function of restrictions to gene flow imposed by oceanographic currents. This study advances our understanding of the role of larval dispersal on the fine-scale genetic structure of coral populations across a complex island system and applies a methodological framework that can be tailored to suit a variety of marine organisms with a range of life-history characteristics.


2009 ◽  
Vol 66 (9) ◽  
pp. 1569-1581 ◽  
Author(s):  
John R. Hyde ◽  
Russell D. Vetter

Recent studies have revealed that the vermilion rockfish Sebastes miniatus is a cryptic species pair. The splitting of this species impacts stock size estimates and draws attention to the unintended consequences of current management policies. Differences in exploitation level between the species necessitated an evaluation of population structure and connectivity among regional management segments of the fishery. Analysis of gene flow and calculations of larval dispersal values were accomplished using 782 bp of DNA sequence data from the mitochondrial cytochrome b gene of 684 vermilion rockfish sampled from 16 sites between Kyuquot Sound, Canada, and San Quintin, Mexico. Significant genetic heterogeneity was found among sample sites (ΦST = 0.0742, p < 0.001 and FST = 0.0899, p < 0.001). Isolation by distance analysis produced a significant correlation, suggesting low average larval dispersal distance. Analysis of molecular variance showed significant partitioning of genetic variance across the biogeographic boundary at Point Conception (ΦCT = 0.0923, p < 0.001 and FCT = 0.0135, p < 0.001) with additional genetic barriers found at Cape Mendocino, Punta Colnett, Santa Monica Bay, and along the coast of Washington. These genetic barriers conform to oceanographic compartments previously proposed for the California Current Ecological Province and suggest natural management units for this species.


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