Seasonal and diel patterns of stream invasion by American eels (Anguilla rostrata) in the northern Gulf of St. Lawrence

1989 ◽  
Vol 67 (1) ◽  
pp. 182-188 ◽  
Author(s):  
J.-D. Dutil ◽  
M. Michaud ◽  
A. Giroux
Keyword(s):  
Anguilla Rostrata ◽  
Small Stream ◽  
Glass Eel ◽  
North Shore ◽  
Diel Patterns ◽  
The North ◽  
Stream Migration ◽  
Glass Eels ◽  
American Eels ◽  
The Relationship

Seasonal and diel patterns of stream invasion by American eels (Anguilla rostrata) were monitored in a small stream located on the north shore of the Gulf of St. Lawrence from 1981 to 1985. Glass eels and elvers migrated from the sea in late June and July. Glass eels made up only a small percentage of the migrants. Pigmentation progressed quickly in the estuary, but elvers grew very slowly. Migration from the estuary and through the lower reaches of the stream was slow; no glass eels or elvers occurred at a station located only 4 km from saltwater. Juvenile eels reached that station in their second summer of stream residence. Juvenile eels migrated in July and August. They ranged from 70 to 250 mm in length and included more than one age-class. Those less than 100 mm in length were most numerous. Relative abundance of glass eels and elvers decreased in the estuary from 1981 to 1985. This coincided with a decrease in the proportion of smaller sized eels in the stream migration over the same period. Juvenile eels migrated progressively later in summer as the proportion of smaller sized eels decreased. Stream migration was nocturnal. Movements mainly occurred between 21:00 and 23:00. The relationship between glass eel and elver abundance in the estuary and juvenile eel abundance in the stream 1 and 2 years later was not clear.

scholarly journals Infection of newly recruited American eels (Anguilla rostrata) by the invasive swimbladder parasite Anguillicoloides crassus in a US Atlantic tidal creek

2015 ◽  
Vol 73 (1) ◽  
pp. 14-21 ◽  
Author(s):  
Jennifer L. Hein ◽  
Isaure de Buron ◽  
William A. Roumillat ◽  
William C. Post ◽  
Allan P. Hazel ◽  
...  
Keyword(s):  
Tidal Creek ◽  
Parasite Prevalence ◽  
Anguilla Rostrata ◽  
American Eel ◽  
Glass Eel ◽  
The Usa ◽  
Advanced Stages ◽  
Glass Eels ◽  
American Eels ◽  
Anguillicoloides Crassus

Abstract Little is known about the infection status of glass eel and elver stages of the American eel Anguilla rostrata by the invasive swimbladder parasite Anguillicoloides crassus. This study examined infection by adult and larval A. crassus in glass eels (n = 274) and elvers (n = 199) collected during March–December 2013 from an eel ladder at a dammed creek near Charleston, SC, USA. Among all the eels examined [total lengths (TLs), 34–156 mm], the prevalence (±SE), mean abundance, and mean intensity of A. crassus worms was 29.4 ± 2.1%, 0.88 ± 0.12, and 2.98 ± 0.34, respectively. Infection by A. crassus was not detected in the earliest glass eel development stages (pigment stages 1–3), but it was detected in more advanced stages (pigment stages 4–7) and fully pigmented elvers. From March to July, parasite prevalence increased significantly with eel TL, and all eels 125 mm or longer (n = 13) were infected. From August–December, when fewer eels were caught, parasite prevalence was generally lower and less dependent on the eel TL. Our study demonstrates the potential risk of spreading A. crassus to new areas by transporting live glass eels and elvers. This is of particular relevance because our study site was located in the Cooper River drainage, one of the few locations in the USA that permits a glass eel harvest.

Challenges to quantifying glass eel abundance from large and dynamic estuaries

2017 ◽  
Vol 75 (2) ◽  
pp. 727-737 ◽  
Author(s):  
Sarah Walmsley ◽  
Julie Bremner ◽  
Alan Walker ◽  
Jon Barry ◽  
David Maxwell
Keyword(s):  
Large Scale ◽  
Anguilla Anguilla ◽  
Commercial Fishing ◽  
European Eel ◽  
Estuarine System ◽  
Glass Eel ◽  
The North ◽  
Adequate Sampling ◽  
South Shore ◽  
Glass Eels

Abstract European eel Anguilla anguilla recruitment into the rivers of the northeastern Atlantic has declined substantially since the 1980s. Monitoring of recruiting juveniles, or glass eels, is usually undertaken in small estuaries and rivers. Sampling of large-scale estuaries is rare, due to the size of the sampling area and the resources needed to provide adequate sampling levels. Here we describe surveys for glass eels in the UK’s largest estuarine system, the Severn Estuary/Bristol Channel. We sampled across a 20 km-wide stretch of the estuary in 2012 and 2013, using a small-meshed net deployed from a commercial fishing trawler, and the surveys yielded over 2500 glass eels. Eels were more abundant in the surface layer (0–1.4 m depth) than at depth (down to 8.4 m depth), were more abundant close to the south shore than along the north shore or middle of the estuary, and were more abundant in lower salinity water. Numbers were higher in the second year than in the first and eels were more abundant in February than April. The difficulties and logistics of sampling in such a large estuary are discussed, along with the level of resources required to provide robust estimates of glass eel abundance.

Correlations between pathological changes and chemical contamination in American eels, Anguilla rostrata, from the St. Lawrence River

1997 ◽  
Vol 54 (8) ◽  
pp. 1916-1927 ◽  
Author(s):  
C M Couillard ◽  
P V Hodson ◽  
M Castonguay
Keyword(s):  
Anguilla Rostrata ◽  
Chemical Contamination ◽  
Pathological Changes ◽  
Preneoplastic Lesions ◽  
Biomarkers Of Exposure ◽  
Reproductive Impairment ◽  
Migratory Season ◽  
American Eels ◽  
The Relationship ◽  
St Lawrence River

American eel (Anguilla rostrata) from the St. Lawrence River are heavily contaminated with chemicals that may be associated with increased incidence of diseases and reproductive impairment. The relationship between tissue mirex concentration and body mass was used to separate eels into two groups: the proportion of eels migrating from contaminated areas (Lake Ontario and upper St. Lawrence River) increased as the migration season progressed. Vertebral malformations and basophilic foci in the liver (preneoplastic lesions) were more frequent at the end of the migratory season, when the eels were more heavily contaminated with organochlorine compounds. In contrast, mesenteric nematodes were more common in the first week of the season, when eels were less contaminated. Diameters and percentages of different stages of oocytes, and density and surface area of pigmented macrophage aggregates in the spleen, did not vary among weeks. While basophilic foci are specific biomarkers of exposure to environmental contaminants, vertebral malformations may be caused by a variety of other anthropogenic or natural factors.\b Further studies are needed to confirm the observed associations between chemical contamination and pathological changes.

Fecundity and Gonad Observations of the American Eel, Anguilla rostrata, Migrating from Chesapeake Bay, Virginia

1974 ◽  
Vol 31 (8) ◽  
pp. 1387-1391 ◽  
Author(s):  
Charles A. Wenner ◽  
J. A. Musick
Keyword(s):  
Chesapeake Bay ◽  
Anguilla Anguilla ◽  
Total Weight ◽  
Anguilla Rostrata ◽  
American Eel ◽  
Total Length ◽  
American Eels ◽  
The Relationship ◽  
Sexually Mature ◽  
Gonadal Condition

Fecundity of the American eel, Anguilla rostrata, was estimated from 21 specimens migrating from Chesapeake Bay during November 1970. The relationship between total length and fecundity is log y = −4.29514 + 3.74418 log x where y is fecundity and x is total length (mm) and between total weight and fecundity is log y = 3.22990 + 1.1157 log x where y is fecundity and x is total weight (g). Gonadal condition was described statistically and histologically. Specimens migrating from Chesapeake Bay are more sexually mature than either American eels migrating from Canadian waters or European eels, Anguilla anguilla, migrating from Europe. The significance of these findings with regard to Tucker's hypothesis of European eels being more sexually advanced at the onset of the spawning migration is discussed.

Rola Avarského Kaganátu Pri Vzniku Slovenčiny

2018 ◽  
Vol 69 (2) ◽  
pp. 199-236
Author(s):  
Martin Braxatoris ◽  
Michal Ondrejčík
Keyword(s):  
Slavic Language ◽  
The West ◽  
The North ◽  
Danube Region ◽  
The Absolute ◽  
North Edge ◽  
The Relationship ◽  
Slovak Language

Abstract The paper proposes a basis of theory with the aim of clarifying the casual nature of the relationship between the West Slavic and non-West Slavic Proto-Slavic base of the Slovak language. The paper links the absolute chronology of the Proto-Slavic language changes to historical and archaeological information about Slavs and Avars. The theory connects the ancient West Slavic core of the Proto-Slavic base of the Slovak language with Sclaveni, and non-West Slavic core with Antes, which are connected to the later population in the middle Danube region. It presumes emergence and further expansion of the Slavic koiné, originally based on the non-West Slavic dialects, with subsequent influence on language of the western Slavic tribes settled in the north edge of the Avar Khaganate. The paper also contains a periodization of particular language changes related to the situation in the Khaganate of that time.

Examining the Kinships System of the Bodo

Think India ◽  
2019 ◽  
Vol 22 (3) ◽  
pp. 186-192
Author(s):  
Dr. Oinam Ranjit Singh ◽  
Dr. Nushar Bargayary
Keyword(s):  
Social Relationships ◽  
Social Cohesion ◽  
Social Relationship ◽  
Vital Role ◽  
Eastern Region ◽  
The North ◽  
Kinship System ◽  
North Eastern ◽  
The World ◽  
The Relationship

The Bodo of the North Eastern region of India have their own kinship system to maintain social relationship since ancient periods. Kinship is the expression of social relationship. Kinship may be defined as connection or relationships between persons based on marriage or blood. In each and every society of the world, social relationship is considered to be the more important than the biological bond. The relationship is not socially recognized, it fall outside the realm of kinship. Since kinship is considered as universal, it plays a vital role in the socialization of individuals and the maintenance of social cohesion of the group. Thus, kinship is considered to be the study of the sum total of these relations. The kinship of the Bodo is bilateral. The kin related through the father is known as Bahagi in Bodo whereas the kin to the mother is called Kurma. The nature of social relationships, the kinship terms, kinship behaviours and prescriptive and proscriptive rules are the important themes of the present study.

A Religious State (A Study of Hasyim Asyari and Muhammad Iqbal's Thought on the Relation of Religion, State and Nationalism)

2020 ◽  
Vol 3 (2) ◽  
pp. 226
Author(s):  
Arik Dwijayanto ◽  
Yusmicha Ulya Afif
Keyword(s):  
Intellectual History ◽  
British Empire ◽  
Political Identity ◽  
British Imperialism ◽  
Early Generation ◽  
North West ◽  
The North ◽  
Religion And State ◽  
The Relationship ◽  
Diverse Cultures

<p><em>This article explores the concept of a religious state proposed by two Muslim leaders: Hasyim Asyari (1871-1947), an Indonesian Muslim leader and Muhammad Iqbal (1873-1938), an Indian Muslim leader. Both of them represented the early generation when the emerging revolution for the independence of Indonesia (1945) from the Dutch colonialism and India-Pakistan (1947) from the British Imperialism. In doing so, they argued that the religious state is compatible with the plural nation that has diverse cultures, faiths, and ethnicities. They also argued that Islam as religion should involve the establishment of a nation-state. But under certain circumstances, they changed their thinking. Hasyim changed his thought that Islam in Indonesia should not be dominated by a single religion and state ideology. Hasyim regarded religiosity in Indonesia as vital in nation-building within a multi-religious society. While Iqbal changed from Indian loyalist to Islamist loyalist after he studied and lived in the West. The desire of Iqbal to establish the own state for the Indian Muslims separated from Hindus was first promulgated in 1930 when he was a President of the Muslim League. Iqbal expressed the hope of seeing Punjab, the North West province, Sind and Balukhistan being one in a single state, having self-government outside the British empire. In particular, the two Muslim leaders used religious legitimacy to establish political identity. By using historical approach (intellectual history), the relationship between religion, state, and nationalism based on the thinking of the two Muslim leaders can be concluded that Hasyim Asyari more prioritizes Islam as the ethical value to build state ideology and nationalism otherwise Muhammad Iqbal tends to make Islam as the main principle in establishment of state ideology and nationalism.</em></p><em>Keywords: Hasyim Asyari, Muhammad Iqbal, religion, state, nationalism.</em>

On Riccia marginata and related species (Ricciaceae, Marchantiophyta)

2012 ◽  
Vol 46 ◽  
pp. 298-305 ◽  
Author(s):  
A. D. Potemkin ◽  
T. Ahti
Keyword(s):  
Related Species ◽  
Lake Ladoga ◽  
Leningrad Region ◽  
Sem Images ◽  
North Shore ◽  
The North ◽  
Molecular Studies ◽  
The Future ◽  
The Town

Riccia marginata Lindb. was described by S. O. Lindberg (1877) from the outskirts of the town of Sortavala near the north shore of Lake Ladoga, Republic of Karelia, Russia. The species has been forgotten in most recent liverwort accounts of Europe, including Russia. Lectotypification of R. marginata is provided. R. marginata shares most characters with R. beyrichiana Hampe ex Lehm. It differs from “typical” plants of R. beyrichiana in having smaller spores, with ± distinctly finely areolate to roughly papillose proximal surfaces and a narrower and shorter thallus, as well as in scarcity or absence of marginal hairs. It may represent continental populations of the suboceanic-submediterranean R. beyrichiana, known in Russia from the Leningrad Region and Karelia only. The variability of spore surfaces in R. beyrichiana is discussed and illustrated by SEM images. A comparison with the spores of R. bifurca Hoffm. is provided. The question how distinct R. marginata is from R. beyrichiana needs to be clarified by molecular studies in the future, when adequate material is available. R. marginata is for the time being, provisionally, included in R. beyrichiana.

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