Effects of environmental factors within the spawning area and migration routes on the length of Anguilla japonica glass eels recruited to Taiwan

Author(s):  
KM Hsiung ◽  
C Ma ◽  
CY Ko ◽  
YH Tseng ◽  
YC Kuo ◽  
...  
The Auk ◽  
2021 ◽  
Author(s):  
Scott F Lovell ◽  
M Ross Lein ◽  
Sean M Rogers

Abstract Eastern (Vireo gilvus gilvus) and western (V. g. swainsoni) forms of the Warbling Vireo have essentially allopatric breeding ranges across north-central North America, but come into contact in central Alberta, Canada. In 1986, Jon Barlow presented preliminary morphological and song evidence suggesting that the Warbling Vireo complex might comprise more than one valid species. However, to date, Barlow’s suggestion is supported by only limited DNA evidence, demonstration of molt and migration differences between the taxa, and anecdotal accounts of differences in song, morphology, plumage, and ecology. We analyzed variation in both mitochondrial and nuclear DNA in birds from Alberta and surrounding areas to determine the levels of genetic differentiation and hybridization occurring in the contact zone, and whether the two taxa warrant recognition as separate biological species. Our analyses reveal that Warbling Vireos in Alberta and the surrounding areas are separated into two well-defined, genetically differentiated, and monophyletic clades corresponding to previously recognized taxonomic groups. The two taxa come into contact in a narrow (~85 km) zone in Barrhead County, northwest of Edmonton, Alberta. They show evidence of limited hybridization. The distinct genetic differences are maintained in the contact zone, where individuals of the two taxa may occupy neighboring territories. Differences in spring arrival dates, molt schedules, and migration routes indicate that a migratory divide may play an important role in reproductive isolation. We suggest that the two taxa are distinct cryptic species: an eastern form, Vireo gilvus, and a western form, Vireo swainsoni.


2012 ◽  
Vol 26 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Renata Piwowarczyk

Abstract Orobanche coerulescens has a Eurasian distribution. The species is classified as extinct at most of its localities at the western limit of its range. Its populations are very scarce and critically endangered in Central Europe. This work presents the current distribution of O.coerulescens in Poland, based on a critical revision of herbarium and literature data as well as results of original field research, and reviews its distribution in Central Europe (partly in Eastern Europe). Habitats, plant communities, and migration routes of O.coerulescens in Central Europe are discussed. The species was initially known in Poland from now historical localities in Pomerania and the valley of the lower Vistula. In 2000-2011 it was recorded at 9 localities in Podlasie, the Małopolska Upland (Wyżyna Małopolska), and the Łódź Hills (Wzniesienia Łódzkie). Its abundance at the localities ranged from a few to over 1000 shoots. These are the largest populations of O.coerulescens at its western and north-western range limits.


2002 ◽  
Vol 59 (12) ◽  
pp. 1845-1850 ◽  
Author(s):  
Luc A Comeau ◽  
Steven E Campana ◽  
Martin Castonguay

The migration patterns of marine fishes are poorly known, in part owing to the technical limitations associated with tracking the movements of animals in deep water. Here we document a large-scale, directed, migration of Atlantic cod (Gadus morhua) off eastern Canada. Our approach was based on the acoustic tagging of 126 fish and the deployment of 69 subsurface receivers, stretching over a 160-km distance along the edge of the Laurentian Channel. After 1 year of automated recording, we found that 65% of the fish migrated out of coastal waters in two distinct runs during the summer–autumn period. The offshore-migrating fish overwintered in deep Laurentian Channel waters, returning inshore in April. Individual migration routes and migration timing were variable, indicating that the cod did not aggregate in large schools during the seasonal migration events.


Author(s):  
О. Mudrak ◽  
G. Mudrak ◽  
V. Serebryakov ◽  
A. Shcherbliuk ◽  
V. Klochaniuk

Based on comprehensive environmental monitoring, geobotanical, zoogeographical, landscape-ecological, hydro-ecological, forest-typological, agroecological principles and approaches and own field research it is proposed to create a national nature park (NNP) «Central Podillya» within Vinnytsia region. A promising NNP is planned to be created on the territory of Vinnytsia and Khmilnytsky administrative districts of Vinnytsia region as a habitat and migration routes of bison (Bison bonasus) and preservation of unique biotic and landscape diversity. The projected area of NPP «Central Podillya» is 53 820 hectares. The need to create a park due to the presence of natural (forest, wetland, peat-swamp, floodplain, meadow, forest-steppe, meadow-steppe, steppe, weed-field) complexes with associations of plant groups, where more than 40 species of plants and lives more than 50 species of animals listed in the RBU, as well as the presence of a significant number of objects that have historical, cultural, recreational, health (medical) value. The general ecological and geographical characteristics of the park from the standpoint of physical-geographical and geobotanical zoning are given. There are 34 objects of the nature reserve fund (NRF), which will be a part of the perspective park. Functional zoning of the territory of the projected NNP «Central Podillya» was carried out taking into account representative and rare ecosystems, where its 4 zones (protected, regulated recreation, stationary recreation, economic) were allocated. The structural elements of the ecological network of the perspective park are singled out. The necessity of protection, preservation and reproduction of biotic and landscape diversity and historical and cultural heritage of the studied territory through the greening of economic activity, education and culture of the local population is substantiated. It was found that the creation of NPP «Central Podillya» through the Presidential Decree and the optimization of protected areas, which account for 2.27% of the total area of Vinnytsia region, the implementation of regional ecological and Emerald networks is an extremely important, important and absolutely necessary for effective adjustment of the strategy of balanced development of territorial communities. Creation of NPP «Central Podillya» will increase the percentage of protected areas to 4.5% of the total area of Vinnytsia region. According to this indicator Vinnytsia region is in one of the last places in Ukraine. According to the Institute of World Resources (Washington), for the effective functioning of the territory, the area of its reserves should be at least 10–12%. Preparation of scientific substantiation and project of creation of NPP «Central Podillya» within Vinnytsia region is a pilot project that requires official detailing, delimitation, land management, coordination with land users on which the park will be located, creation of park directorate, introduction of technologies aimed at preservation and restoration of biogeocenotic cover, reproduction of broken types of connections, preservation of settlements, optimization of land use, balanced development of territorial communities that will be a part of the NNP.


Author(s):  
KAZIM ABDULLAEV

This chapter examines the ethnic and cultural identities and migration routes of nomadic tribes in Central Asia. It explains that the migration of Central Asian nomads, particularly into Transoxiana, can be divided into two categories. One is the long trans-regional route ascribable to the migration of the Yuezhi tribe from the valley of Gansu to the territory north of the Oxus River, and the other is the local migration attributed to the tribes such as the Dahae, Sakaraules, and Appasiakes. The chapter suggests that the events which determined nomad migration are connected with the history of the northern and western borders of Han China in the second century BC.


1998 ◽  
Vol 64 (2) ◽  
pp. 235-239 ◽  
Author(s):  
Yutaka Kawakami ◽  
Noritaka Mochioka ◽  
Akinobu Nakazono
Keyword(s):  

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yu-Lin K. Chang ◽  
Eric Feunteun ◽  
Yasumasa Miyazawa ◽  
Katsumi Tsukamoto

Abstract The Sargasso Sea has long been considered as the only spawning area for Atlantic eels, despite the absence of direct observations. The present study raises a novel scenario, deviating from Schmidt’s dogma, begins with a review of historical and recent observations that were combined to build up a global theory on spawning ecology and migration behavior of Atlantic eels. From this, it is argued that a favorable spawning area could be located eastward of Sargasso Sea at the intersection between the Mid-Atlantic Ridge and the oceanic fronts. Ocean circulation models combined with 3D particle-tracking method confirmed that spawning at this specific area would result in larval distribution fitting the field observation. This study explores the hypothesis that leptocephali are able to swim and orientate to reach their specific growth areas. It proposes a novel framework about spawning ecology, based on orientation, navigation and meeting cues of silver eels to the spawning area. Together this framework may serve as a stepping-stone for solving the long-lasting mystery of eel reproduction which first came out 2,400 years ago and promotes the understanding of oceanic migration and reproduction of marine organisms.


2020 ◽  
Vol 77 (2) ◽  
pp. 593-603 ◽  
Author(s):  
Ana Almodóvar ◽  
Graciela G Nicola ◽  
Daniel Ayllón ◽  
Clive N Trueman ◽  
Ian Davidson ◽  
...  

Abstract Historical data on the oceanic distribution and migration routes of southernmost Atlantic salmon Salmo salar populations from Europe are almost non-existent, as no rigorous tagging initiatives have been conducted. Here, we used stable isotope data (δ13C and δ15N) of historic scale collections to identify the potential marine feeding areas of the largest salmon population in the Iberian Peninsula. Data were compared with published datasets from Northern Ireland, Wales, south England, and northeast UK coast, which correspond to series between 15- and 33-year long within the time period from 1958 to 2009. Temporal covariation in sea surface temperature, primary productivity, and δ13C values suggests that feeding areas of Iberian salmon are located around Greenland, both in the Labrador and the Irminger seas. Furthermore, δ13C values of Atlantic salmon from Canadian rivers reported in the literature are similar to those found in individuals from Spanish rivers. Our results suggest that Iberian salmon follow a westerly migration route towards Greenland instead of following the easterly branch of the North Atlantic current into the Norwegian Sea. Characterization of feeding patterns and migration routes might help to understand the causes of ongoing population decline and establish targeted conservation programmes for threatened Iberian salmon.


2010 ◽  
Vol 20 (3) ◽  
pp. 240-254 ◽  
Author(s):  
STEVEN W. EVANS ◽  
H. BOUWMAN

SummaryThe Blue Swallow Hirundo atrocaerulea is restricted to sub-Saharan Africa, its population size previously estimated at fewer than 1,500 pairs, and is classified as Vulnerable. A better understanding of its current distributional range, population size, protection status and migration routes would improve our ability to conserve the species and the grassland and wetland habitat on which it depends. We now estimate that the Blue Swallow population in the 1850s may have numbered between 1,560 and 2,300 pairs. Based on an assessment of available data, we now estimate the total current Blue Swallow population at 1,006 pairs or 2,012 individuals, an estimated 36–56% decline over the last 150 years. There may be three separate Blue Swallow sub-populations and seven separate migratory routes between their breeding and non-breeding grounds. The Blue Swallow’s range in South Africa and Swaziland has contracted by 74%. The majority of Blue Swallows occupy unprotected areas on their non-breeding grounds in the Democratic Republic of the Congo, Uganda and Kenya. The Blue Swallow population in Africa will continue to decline unless the causes of reduction in Blue Swallow habitat quantity and quality can be stopped and sufficient and additional habitat set aside to sustain viable Blue Swallow populations throughout their range.


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