The Swimbladder Nematode Anguillicola crassus in American Eels (Anguilla rostrata) from Middle and Upper Regions of Chesapeake Bay

2001 ◽  
Vol 87 (6) ◽  
pp. 1366 ◽  
Author(s):  
Ann M. Barse ◽  
Scott A. McGuire ◽  
Melissa A. Vinores ◽  
Laura E. Eierman ◽  
Julie A. Weeder
Keyword(s):  
Chesapeake Bay ◽  
Anguilla Rostrata ◽  
Anguillicola Crassus ◽  
American Eels

THE SWIMBLADDER NEMATODE ANGUILLICOLA CRASSUS IN AMERICAN EELS (ANGUILLA ROSTRATA) FROM MIDDLE AND UPPER REGIONS OF CHESAPEAKE BAY

2001 ◽  
Vol 87 (6) ◽  
pp. 1366-1370 ◽  
Author(s):  
Ann M. Barse ◽  
Scott A. McGuire ◽  
Melissa A. Vinores ◽  
Laura E. Eierman ◽  
Julie A. Weeder
Keyword(s):  
Chesapeake Bay ◽  
Anguilla Rostrata ◽  
Anguillicola Crassus ◽  
American Eels

Occurrence of American Eels, Anguilla rostrata, in Waters Overlying the Eastern North American Continental Shelf

1973 ◽  
Vol 30 (11) ◽  
pp. 1752-1755 ◽  
Author(s):  
Charles A. Wenner
Keyword(s):  
Continental Shelf ◽  
Chesapeake Bay ◽  
North American ◽  
Cape Cod ◽  
Anguilla Rostrata ◽  
American Eel ◽  
Morphometrical Analysis ◽  
Assateague Island ◽  
American Eels

Eleven reproductively maturing specimens of the American eel, Anguilla rostrata, were collected during three independent off-shore trawling operations. Three females were taken on December 5, 1967 southeast of the mouth of Chesapeake Bay in 10–13 fathoms, one male and one female on November 5, 1969 southeast of Cape Cod in 35–45 fathoms, and six females east of Assateague Island on December 22, 1971 in 5 fathoms. Morphometrical analysis showed that the specimens were within the range of "silver" phase of Anguilla rostrata. Gonadal observations were made on all specimens.

Eels at the Edge: Science, Status, and Conservation Concerns

2009 ◽  
Keyword(s):  
Chesapeake Bay ◽  
Atlantic Coast ◽  
Mortality Rates ◽  
Reference Points ◽  
Anguilla Rostrata ◽  
Fishing Mortality ◽  
Population Status ◽  
Bell Model ◽  
American Eels ◽  
Yield Per Recruit

<em>Abstract.—</em>We investigated yield per recruit and spawner biomass per recruit of American eels <em>Anguilla rostrata </em>in five commercially fished estuarine river systems to determine population status, using a modified form of the Thompson-Bell model. We estimated three biological reference points with this model: <EM>F</EM><sub>m</sub><sub>ax</sub>, <EM>F</EM><sub>0.1</sub>, and <EM>F</EM><sub>replacement</sub>; eels appeared overfished relative to these reference points. Current fishing mortality rates (<EM>F</EM>) ranged from 0.37 to 1.19, while <EM>F</EM><sub>max </sub>ranged from 0.33 to 0.51, <EM>F</EM><sub>0.1 </sub>ranged from 0.24 to 0.35, and <EM>F</EM><sub>replacement </sub>ranged from 0.20 to 0.32. The percentage of maximum spawning potential (%MSP) needed for replacement of the stock was estimated at 33%, but current %MSP varied between 1% and 28%. ICES guidelines recommend that <EM>F </EM>equal <EM>M </EM>in data-poor situations, but <EM>F</EM>s in Maryland’s upper Chesapeake Bay were two to four times larger than <EM>M</EM>. American eel populations in the Chesapeake Bay region may now depend on recruitment from other areas along the Atlantic coast where fishing mortality is low.

Demographic attributes of yellow-phase American eels (Anguilla rostrata) in the Hudson River estuary

2003 ◽  
Vol 60 (12) ◽  
pp. 1487-1501 ◽  
Author(s):  
Wendy E Morrison ◽  
David H Secor
Keyword(s):  
Brackish Water ◽  
Loss Rate ◽  
River Estuary ◽  
Hudson River ◽  
Anguilla Rostrata ◽  
Short Term ◽  
Anguillicola Crassus ◽  
Study Support ◽  
Demographic Attributes ◽  
American Eels

Management of American eels (Anguilla rostrata) requires an understanding of how demographic attributes vary within large estuaries. Yellow-phase American eel length and age structure, growth, dispersal, nematode infestation rates, loss rate (natural mortality and emigration), and production were measured at six sites throughout the tidal portion of the Hudson River. Short-term dispersal was low, with >70% of eels at all sites captured <1 km from their original tagging area. Length was similar among sites (total length = 45.7 ± 0.3 cm), whereas age was substantially lower for brackish-water sites (8 ± 4 years) than for freshwater sites (17 ± 4 years). Growth was higher for brackish-water sites than for freshwater sites (8.0 cm·year–1 and 3.4 cm·year–1, respectively). From 1997 to 2000, infestation by the exotic nematode Anguillicola crassus increased dramatically in mean intensity as well as prevalence. Annual loss rates measured for the six sites varied between 9% and 24%, with no statistical difference between freshwater and brackish-water sites. Estimated eel production was higher in a brackish-water habitat (1.10–1.77 kg·ha–1·year–1) than in a freshwater location (0.21–0.58 kg·ha–1·year–1). The results of this study support a recent proposal to establish freshwater areas as exploitation reserves.

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.

scholarly journals Deep Learning for Automated Detection and Identification of Migrating American Eel Anguilla rostrata from Imaging Sonar Data

2021 ◽  
Vol 13 (14) ◽  
pp. 2671
Author(s):  
Xiaoqin Zang ◽  
Tianzhixi Yin ◽  
Zhangshuan Hou ◽  
Robert P. Mueller ◽  
Zhiqun Daniel Deng ◽  
...  
Keyword(s):  
Deep Learning ◽  
Fish Passage ◽  
Automated Detection ◽  
Anguilla Rostrata ◽  
Automated Method ◽  
Detection And Identification ◽  
And Migration ◽  
Imaging Sonar ◽  
American Eels ◽  
Deep Learning Model

Adult American eels (Anguilla rostrata) are vulnerable to hydropower turbine mortality during outmigration from growth habitat in inland waters to the ocean where they spawn. Imaging sonar is a reliable and proven technology for monitoring of fish passage and migration; however, there is no efficient automated method for eel detection. We designed a deep learning model for automated detection of adult American eels from sonar data. The method employs convolution neural network (CNN) to distinguish between 14 images of eels and non-eel objects. Prior to image classification with CNN, background subtraction and wavelet denoising were applied to enhance sonar images. The CNN model was first trained and tested on data obtained from a laboratory experiment, which yielded overall accuracies of >98% for image-based classification. Then, the model was trained and tested on field data that were obtained near the Iroquois Dam located on the St. Lawrence River; the accuracy achieved was commensurate with that of human experts.

Artificial maturation, fertilization, and early development of the American eel (Anguilla rostrata)

2010 ◽  
Vol 88 (11) ◽  
pp. 1121-1128 ◽  
Author(s):  
K. Oliveira ◽  
W. E. Hable
Keyword(s):  
Early Development ◽  
Anguilla Rostrata ◽  
Sargasso Sea ◽  
American Eel ◽  
Important Species ◽  
Vitro Fertilization ◽  
Commercially Important ◽  
Elusive Species ◽  
American Eels

Spawning for the American eel ( Anguilla rostrata (Le Sueur, 1817)) takes place in secretive locations within the Sargasso Sea, which has thus far prevented investigations of gametogenesis and early development in this ecologically and commercially important species. Attempts to induce maturation and reproduction in this species have been few and have produced limited results, with a single report of the production of gastrula-stage embryos. Here we report the successful maturation of female American eels. Maturation occurred within 13 weeks and ovulation was induced with a single injection of 17α,20β-dihydroxy-4-pregnen-3-one (DHP). Following in vitro fertilization, embryogenesis through hatching was observed and larvae were maintained for up to 6 days. We show that a crucial factor for successful fertilization is the stage of the oocyte at the time of induced ovulation. Oocytes that had not reached the migratory nucleus stage, or had passed this stage, were not successfully fertilized. These findings demonstrate that American eel can reproduce in the laboratory and previously untestable hypotheses pertaining to the developmental biology of this elusive species can now be explored.

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