Usefulness of Meristic and Morphometric Characters in Discriminating Populations of American Shad (Alosa sapidissima) (Ostreichthyes:Clupeidae) Inhabiting a Marine Environment

1992 ◽  
Vol 49 (2) ◽  
pp. 266-280 ◽  
Author(s):  
Gary D. Melvin ◽  
Michael J. Dadswell ◽  
Joseph A. McKenzie

American shad (Alosa sapidissima) concentrate each summer in the basins of the inner Bay of Fundy during their coastal migration. Tag returns from 6124 marked shad indicated that these fish return to every important shad spawning stream on the Atlantic coast. Ten meristic and 16 morphometric characters of shad collected from 14 rivers (range: Florida to Quebec) were used to develop linear discriminant functions (LDF). Variables which differed significantly (p < 0.05) between the sexes, year of sampling, and the time of collection during the spawning run were removed prior to LDF classification. The highest mean percent correct classification was achieved by the allocation of fish into regional groups, after classification into individual rivers, using pooled meristic and morphometric variables: 87.2% for males and 82.4% for females. The functions were then used to assign shad from a mixed populations (Cumberland Basin) to individual rivers and regions. Of these, 10.9% were assigned to rivers south of Cape Lookout, North Carolina, 38.1% to rivers between Cape Lookout and Cape Cod, 32.5% into rivers of the Bay of Fundy, and 18.5% into rivers in the Gulf of St. Lawrence. In-river tag returns were compared with LDF classification and were found to be similar.


1983 ◽  
Vol 40 (S1) ◽  
pp. s322-s330 ◽  
Author(s):  
M. J. Dadswell ◽  
G. D. Melvin ◽  
P. J. Williams

Since 1750, a unique, directed fishery for American shad (Alosa sapidissima) has existed in shallow, turbid, mega-tidal embayments of the inner Bay of Fundy during summer and fall. Tagging experiments indicated that migrating shad consisting of intermixed, river populations from the entire Atlantic coast of North America occur there between June and October. Shad migration was counterclockwise around the Bay following the residual current structure. Presence and duration of the shad run in Cumberland Basin was a result of interaction between migration timing, turbidity, and temperature. Mean daytime swimming depth was related to tidal phase and turbidity. High turbidity (Secchi [Formula: see text]) of the mega-tidal embayments apparently extends the preference zone for light intensity of ocean-feeding shad into surface waters (2–10 m), making them accessible to the local fishery.Key words: drift gillnets, shad migration, light intensity preference, swimming depth, mega-tidal, eastern Canada



1993 ◽  
Vol 71 (5) ◽  
pp. 941-946 ◽  
Author(s):  
W. E. Hogans ◽  
Michael J. Dadswell ◽  
Leslie S. Uhazy ◽  
Ralph G. Appy

Parasites belonging to a total of 26 taxa were recovered from 695 American shad (Alosa sapidissima) sampled from six rivers and one marine location (Cumberland Basin, Bay of Fundy) on the east coast of North America. Of these, 23 taxa are reported from American shad for the first time. Species identified were predominantly boreal marine forms that have low host specificities and widespread distributions. Two species, Hysterothylacium aduncum and Scolex pleuronectis, were found in American shad from all localities (> 60% prevalence). Relative abundance and diversity indices of the parasite assemblages varied in relation to geographic location and temporally in Cumberland Basin. These data suggest that there is different timing of arrival and departure of shad from individual river populations in Cumberland Basin. High levels of prevalence and incidence of exotic, southern parasite species, such as Genitocotyle atlantica, in shad from Cumberland Basin and most or all river populations indicate that all individual shad spend some portion of their life at or near the southern extent of their reported range.



1991 ◽  
Vol 48 (9) ◽  
pp. 1724-1734 ◽  
Author(s):  
Kathleen Nolan ◽  
Joseph Grossfield ◽  
Isaac Wirgin

We used restriction endonuclease analysis of mitochondrial DNA (mtDNA) to differentiate among spawning stocks of American shad (Alosa sapidissima). Highly purified mtDNA was isolated from shad from four major spawning rivers: the St. John's (Florida), the Delaware, and the Hudson in the United States and the Miramichi in New Brunswick, Canada. Primarily four-and-five-base-cutting restriction enzymes were used to prepare both individual enzyme profiles and composite genotypes. Three separate spawning stocks, St. John's, Delaware–Hudson, and Miramichi, could be distinguished based on frequency differences in mtDNA genotypes generated by single restriction enzyme digests. We could not distinguish Delaware from Hudson River shad. Only a single definitive restriction site polymorphism was observed among all samples, but polyacrylamide gel electrophoretic mobility variants were common. Eco RI, Dde I, and Rsa I revealed stock-specific mtDNA genotypes. The frequencies of some genotypes occurred in latitudinal clines. Fifty-seven of 81 fish showed individual-specific composite genotypes. Geographic partitioning of genotypes suggests that mtDNA analysis may be useful for the identification of some American shad stocks and their relative contributions to mixed coastal fisheries.



1969 ◽  
Vol 26 (5) ◽  
pp. 1121-1131 ◽  
Author(s):  
J. C. Medcof ◽  
M. L. H. Thomas

Distribution of drills (Urosalpinx cinerea Say) was worked out from critical examination of museum holdings, from assessment of published and several unpublished occurrence records, and from field collection in new areas. Drills occur in warm inlets on the Nova Scotia coast of the Bay of Fundy, possibly in one inlet of the outer Atlantic coast of Nova Scotia, and in several inlets of the southwestern Gulf of St. Lawrence. Only in the last were oysters found with the drills and there is only one record of serious damage to young oysters. Distribution patterns suggest that drills reached the Gulf of St. Lawrence by spreading eastward from Cape Cod, through the Bay of Fundy, then through a channel that is believed to have connected the Bay and the Gulf. There is no evidence of long-term restriction of distributional range since that pioneering period, but local distribution seems to have contracted so that now drills occupy only the warmest parts of their range. In the last 30 years, drill abundance in some important oyster-producing sections of the Gulf of St. Lawrence has decreased, perhaps because of low sea temperatures. Old colonies persist but do little damage in oyster areas. No new colonies seem to have sprung up. In our area the species seems to be bordering on extinction. Drills are not a threat to the Canadian east-coast oyster industry.



2014 ◽  
Vol 34 (6) ◽  
pp. 1190-1198 ◽  
Author(s):  
John Waldman ◽  
Daniel Hasselman ◽  
Paul Bentzen ◽  
Michael Dadswell ◽  
Lorraine Maceda ◽  
...  


1977 ◽  
Vol 34 (9) ◽  
pp. 1422-1426 ◽  
Author(s):  
William C. Leggett

Ocean migration rates of American shad (Alosa sapidissima), estimated from tag returns, averaged 21 km/day during the spring northward migration along the Atlantic coast between Chesapeake Bay and the Bay of Fundy and appear to be regulated by temperature preferences of the species. The fall southward migration is believed to occur at a similar rate. An evaluation of known saltwater swimming speeds and of prevailing currents along the migratory path indicates that the distance traveled during the northward and southward migrations may exceed the minimum distance route by up to 100 and 500%, respectively, and suggests that considerable nondirected movement may occur. The sustained swimming speeds of juvenile shad at the time of their entry into the sea are close to the estimated minimum sustained speeds required to complete the initial migration in the sea. Annual density-dependent variation in individual growth rate, through its influence on size at emigration and the resulting swimming performance of juveniles, may significantly influence juvenile survival. Key words: American shad, Alosa sapidissima, migration rates, swim speeds, survival



1986 ◽  
Vol 43 (3) ◽  
pp. 640-646 ◽  
Author(s):  
Gary D. Melvin ◽  
Michael J. Dadswell ◽  
James D. Martin

Of 5074 adult American shad, Alosa spidissima, tagged in the Annapolis River, Nova Scotia, during the 1981 and 1982 spawning runs, 292 (5.8%) were recaptured, 180 in the river during the same year, 56 in the river in subsequent years, 53 at distant marine sites, and 1 in another Nova Scotia river. Recovery from 6124 adult shad tagged in a marine environment (Cumberland Basin, Bay of Fundy) was similar (395 recaptures, 6.5%) but distribution was markedly different. Thirty-five were taken in the Basin during the same year, but only 7 in subsequent years. Conversely, 139 were recaptured at distant marine sites, and 214 in rivers from the St. Lawrence River, Quebec, to the St. John's River, Florida. Assuming equal probabilities for recapture within this species' geographical range, Annapolis River freshwater recaptures were specific for the Annapolis River but Cumberland freshwater recaptures were nonspecific. Except for two returns, possible strays, fidelity to the Annapolis was 97%.



2012 ◽  
Vol 524-527 ◽  
pp. 2118-2121
Author(s):  
Xiao Min Wang ◽  
Wen Long Wu ◽  
Wei Lin Li ◽  
Chun Hong Zhang ◽  
Shu Ying Hu

The beach plum, Prunus maritima Marsh is native to the sandy North Atlantic coast, from Newfoundland to North Carolina. It can grow well without irrigation, even on low-nutrient sandy soils, saline land, old-field and coastal beach where many other plants cannot survive. It is fine rootstock to improve stress tolerance of cion. The fruits of beach plum can be made into delicious jams, jellies and wine. This paper is aimed to introduce beach plum to people, and hope it can become an important multipurpose crop in Chinese coastal beach in the future.



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