scholarly journals Temporal and spatial genetic variation of Engraulis encrasicolus in the Adriatic Sea

2021 ◽  
Author(s):  
SARA MALAVOLTI ◽  
PAOLO RUGGERI ◽  
TATIANA FIORAVANTI ◽  
JEKOSLAV TIČINA ◽  
ILARIA COSTANTINI ◽  
...  
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Adriatic Sea ◽  
Environmental Changes ◽  
Marine Ecosystem ◽  
European Anchovy ◽  
Engraulis Encrasicolus ◽  
The North ◽  
Temporal And Spatial ◽  
Spatial Genetic Variation

Small pelagic fish play a key role in the marine ecosystem, controlling predator abundance and regulating primary production rates by foraging on plankton. Alterations induced at different ecological levels by fishing activities and/or environmental changes are affecting the reproductive success of several small pelagics, including European anchovy (Engraulis encrasicolus), which is a major target of Adriatic mid-water trawl and purse-seine fisheries. In this study, we evaluated short-term genetic changes of the species in the Adriatic Sea by applying molecular markers in three generations samples of European anchovy. Thirteen polymorphic microsatellite markers and a mitochondrial gene were used in cohorts of adults and larvae, collected at three sites in the north-east, central and southern Adriatic Sea in 2015. Furthermore, temporal and spatial genetic variation was assessed by comparing the dataset above with a sample of adult anchovy collected in 2012 at three sites close to those sampled in 2015. Expected heterozygosity was higher in adults than in larvae, suggesting a loss of genetic diversity and uneven reproduction. In addition, comparison of the two datasets demonstrated a change in the anchovy population structure from 2012 to 2015. In the reproductive event of 2015, this change led the two main genetic stocks described in the Adriatic Sea to merge into one. We suggest that the population structure of European anchovy in the north-eastern Adriatic may be influenced by changes in environmental parameters and by periodic alterations in the temporal pattern of population connectivity.

Population structure in two geographically sympatric and congeneric ectoparasites (Cimex adjunctus and Cimex lectularius) in the North American Great Lakes region

2017 ◽  
Vol 95 (12) ◽  
pp. 901-907 ◽  
Author(s):  
Benoit Talbot ◽  
Maarten J. Vonhof ◽  
Hugh G. Broders ◽  
M. Brock Fenton ◽  
Nusha Keyghobadi
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Isolation By Distance ◽  
Spatial Genetic Structure ◽  
Geographic Area ◽  
Abundant Species ◽  
Cimex Lectularius ◽  
Genetic Structuring ◽  
The North ◽  
Genetic Clusters

Subdivided populations can be described by different models of population structure that reflect population organization, dynamics, and connectivity. We used genetic data to investigate population structure in two geographically sympatric, congeneric species of generalist ectoparasites of warm-blooded animals. We characterized the spatial genetic structure of the eastern bat bug (Cimex adjunctus Barber, 1939), an understudied and fairly abundant species, using microsatellite markers at a spatial scale representing contemporary dispersal of the species. We found seven genetic clusters, global [Formula: see text] of 0.2, 33% of genetic variation among sites, and nonsignificant isolation-by-distance. We compared these results with the common bed bug (Cimex lectularius L., 1758), a closely related but conversely well-known species, in the same geographic area. We found stronger genetic structuring in C. lectularius than in C. adjunctus, with 11 genetic clusters, [Formula: see text] of 0.7, 57% of genetic variation among sites, and significant but weak isolation-by-distance (R2 = 0.09). These results suggest that while both species can be described as having classic metapopulation structure, C. adjunctus leans more towards a patchy population and C. lectularius leans more towards a nonequilibrium metapopulation. The difference in population structure between these species may be attributable to differences in movement potential and extinction–colonization dynamics.

scholarly journals Stock Identification of Engraulis encrasicolus (Linnaeus, 1758) by Discriminant Function Analysis (DFA) of Morphometric Characters in The North of Atlantic and Mediterranean Moroccan Coasts

2021 ◽  
Vol 21 (11) ◽  
pp. 553-558
Author(s):  
Mouna El qendouci ◽  
Fatima Wariaghli ◽  
Mehria Saadaoui ◽  
Lobna Boudaya ◽  
Lassad Neifar ◽  
...  
Keyword(s):  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis ◽  
Stock Structure ◽  
Morphometric Characters ◽  
European Anchovy ◽  
Engraulis Encrasicolus ◽  
The North ◽  
Fishing Vessels ◽  
The Mediterranean

The European anchovy, Engraulis encrasicolus (Linnaeus, 1758) is a small pelagic fish found in the eastern Atlantic, the Mediterranean Sea and the Black Sea. Anchovy (E. encrasicolus) are among the important finfishes harvested in Moroccan coasts. The stock structure of European anchovy in NW Africa is not truly known (FAO, 2013). To effectively manage the anchovy fisheries, it is important to understand the anchovy stock structure. Therefore, discriminant function analysis (DFA) based on morphometric characters was conducted on a total of 204 adult anchovy specimens, seasonally collected by commercial fishing vessels from the region of Mehdia in the North Atlantic area and from the region of M’diq in the Mediterranean coast during the year 2019. Body shape variation, which is often environmentally induced, may provide a good record population structuring. Our data were subjected to univariate statistics of variance (ANOVA) by using SPSS 20 software version. The morphometric characteristics show a separation of two stocks of Engraulis encrasicolus between the two localities. These findings will have major implications for anchovy fisheries management in Morocco.

Temporal and Spatial Genetic Variation within and Among Populations of the MosquitoCulex tarsalis(Diptera: Culicidae) from California

1999 ◽  
Vol 36 (1) ◽  
pp. 23-29 ◽  
Author(s):  
John E. Gimnig ◽  
William K. Reisen ◽  
Bruce F. Eldridge ◽  
Katherine C. Nixon ◽  
Stephen J. Schutz
Keyword(s):  
Genetic Variation ◽  
Temporal And Spatial ◽  
Spatial Genetic Variation

scholarly journals Historical gene flow constraints in a northeastern Atlantic fish: phylogeography of the ballan wrasse Labrus bergylta across its distribution range

2017 ◽  
Vol 4 (2) ◽  
pp. 160773 ◽  
Author(s):  
Frederico Almada ◽  
Sara M. Francisco ◽  
Cristina S. Lima ◽  
Richard FitzGerald ◽  
Luca Mirimin ◽  
...  
Keyword(s):  
Population Structure ◽  
North Atlantic ◽  
Environmental Changes ◽  
Ecological Factors ◽  
Glacial Refugia ◽  
Distribution Range ◽  
The North ◽  
Circulation Patterns ◽  
The North Atlantic ◽  
Labrus Bergylta

The distribution and demographic patterns of marine organisms in the north Atlantic were largely shaped by climatic changes during the Pleistocene, when recurrent glacial maxima forced them to move south or to survive in northern peri-glacial refugia. These patterns were also influenced by biological and ecological factors intrinsic to each species, namely their dispersion ability. The ballan wrasse ( Labrus bergylta ), the largest labrid fish along Europe's continental margins, is a target for fisheries and aquaculture industry. The phylogeographic pattern, population structure, potential glacial refugia and recolonization routes for this species were assessed across its full distribution range, using mitochondrial and nuclear markers. The existence of a marked population structure can reflect both recolonization from three distinct glacial refugia and current and past oceanographic circulation patterns. Although isolated in present times, shared haplotypes between continental and Azores populations and historical exchange of migrants in both directions point to a common origin of L. bergylta . This situation is likely to be maintained and/or accentuated by current circulation patterns in the north Atlantic, and may lead to incipient speciation in the already distinct Azorean population. Future monitoring of this species is crucial to evaluate how this species is coping with current environmental changes.

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