Ocean Migration Rates of American Shad (Alosa sapidissima)

1977 ◽  
Vol 34 (9) ◽  
pp. 1422-1426 ◽  
Author(s):  
William C. Leggett
Keyword(s):  
Swimming Performance ◽  
Atlantic Coast ◽  
Similar Rate ◽  
American Shad ◽  
Individual Growth ◽  
Alosa Sapidissima ◽  
Migration Rates ◽  
Migratory Path ◽  
Temperature Preferences ◽  
Individual Growth Rate

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

Discrimination among Atlantic Coast Populations of American Shad (Alosa sapidissima) Using Mitochondrial DNA

1991 ◽  
Vol 48 (9) ◽  
pp. 1724-1734 ◽  
Author(s):  
Kathleen Nolan ◽  
Joseph Grossfield ◽  
Isaac Wirgin
Keyword(s):  
Mitochondrial Dna ◽  
Atlantic Coast ◽  
Restriction Enzymes ◽  
Hudson River ◽  
Restriction Endonuclease Analysis ◽  
The United States ◽  
American Shad ◽  
Alosa Sapidissima ◽  
Coastal Fisheries ◽  
Latitudinal Clines

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.

Effect of Turbidity on the Temporal and Spatial Utilization of the Inner Bay of Fundy by American Shad (Alosa sapidissima) (Pisces: Clupeidae) and its Relationship to Local Fisheries

1983 ◽  
Vol 40 (S1) ◽  
pp. s322-s330 ◽  
Author(s):  
M. J. Dadswell ◽  
G. D. Melvin ◽  
P. J. Williams
Keyword(s):  
Light Intensity ◽  
Atlantic Coast ◽  
American Shad ◽  
Bay Of Fundy ◽  
Eastern Canada ◽  
Alosa Sapidissima ◽  
Migration Timing ◽  
Swimming Depth ◽  
Preference Zone ◽  
High Turbidity

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

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
Keyword(s):  
North Carolina ◽  
Atlantic Coast ◽  
American Shad ◽  
Cape Cod ◽  
Bay Of Fundy ◽  
Morphometric Characters ◽  
Alosa Sapidissima ◽  
Linear Discriminant ◽  
Percent Correct ◽  
Spawning Run

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.

scholarly journals How lipid content and temperature affect American shad (Alosa sapidissima) attempt rate and sprint swimming: implications for overcoming migration barriers

2019 ◽  
Vol 76 (12) ◽  
pp. 2235-2244
Author(s):  
Shannon M. Bayse ◽  
Stephen D. McCormick ◽  
Theodore Castro-Santos
Keyword(s):  
Lipid Content ◽  
Swimming Performance ◽  
Fork Length ◽  
American Shad ◽  
Seasonal Effects ◽  
Upstream Migration ◽  
Alosa Sapidissima ◽  
Migration Barriers ◽  
Sprint Swimming ◽  
Swimming Endurance

How seasonal effects such as temperature increases and reduced lipid content affect the ability of anadromous fishes to traverse high-velocity barriers and sprint swimming is poorly understood. We evaluated American shad (Alosa sapidissima) swimming performance in a flume against high flow velocities (2.5–3.7 m·s−1) during the upstream migration period (April–May; temperatures 11.1–21.4 °C) to determine how their willingness to enter a velocity barrier (attempt rate) and their swimming endurance changed during migration. American shad did not make attempts at low temperatures, and attempt rate gradually increased throughout the migration as temperatures warmed. American shad displayed two distinct, nonsustained swimming modes (prolonged and sprint swimming), and endurance was different between sexes. At warmer temperatures, females swam at prolonged speeds more often and longer females displayed a lower endurance. Males primarily swam at sprint speeds and were affected by swimming speed, fork length, and lipid content. Our results indicate that American shad motivation and swimming endurance change over the course of the migration as conditions change, potentially limiting their ability to pass barriers.

Role of Olfaction and Vision in the Behavior of American Shad (Alosa sapidissima) Homing to the Connecticut River from Long Island Sound

1974 ◽  
Vol 31 (10) ◽  
pp. 1607-1619 ◽  
Author(s):  
Julian J. Dodson ◽  
William C. Leggett
Keyword(s):  
Tidal Current ◽  
Long Island ◽  
Long Island Sound ◽  
American Shad ◽  
Connecticut River ◽  
Alosa Sapidissima ◽  
Preferred Direction ◽  
Tidal Current Velocity ◽  
Migratory Path ◽  
Island Sound

Twenty-two adult American shad (Alosa sapidissima), captured, sensory-impaired, sonic-tagged, and released adjacent to and 10 km west of the Connecticut River, were tracked in Long Island Sound in 1972. Both anosmic and blind/anosmic shad oriented into the tidal current and altered swimming speeds in relation to changes in tidal current velocity as do unimpaired fish. They did not, however, exhibit the consistency in these behavioral responses that resulted in westerly displacement in unimpaired shad. Blind shad exhibited neither of these behavior patterns but did tend to affect a westerly displacement in Long Island Sound.Dart-tagged adult shad that were sensory-impaired and released without displacement in the same areas of Long Island Sound in 1971 and 1972 homed less successfully to the Connecticut River than did unimpaired dart-tagged shad released in the same years. Anosmic dart-tagged shad located the Connecticut River less successfully than unimpaired shad. Blind shad successfully located the river from 10 km distance but failed to do so when released adjacent to the river. Blind/anosmic shad failed to locate the river from either release site.It was concluded that an olfactory–rheotaxic mechanism forms the basis of the location of the Connecticut River by shad. The preferred direction of displacement appears to be established by olfactory clues indicative of the Connecticut River whereas the orientation along the migratory path is maintained by reference to the rate and direction of tidal currents. Vision alone cannot account for this rheotaxic response.

Parasites of American shad, Alosa sapidissima (Osteichthyes: Clupeidae), from rivers of the North American Atlantic coast and the Bay of Fundy, Canada

1993 ◽  
Vol 71 (5) ◽  
pp. 941-946 ◽  
Author(s):  
W. E. Hogans ◽  
Michael J. Dadswell ◽  
Leslie S. Uhazy ◽  
Ralph G. Appy
Keyword(s):  
Atlantic Coast ◽  
Geographic Location ◽  
Diversity Indices ◽  
American Shad ◽  
Bay Of Fundy ◽  
Alosa Sapidissima ◽  
The North ◽  
Abundance And Diversity ◽  
First Time ◽  
Hysterothylacium Aduncum

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.

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