American Shad

REFElRENCE cur r Do Not Remove from the Library U. S. Fish and Wildlife Service

Notional. .-- Wetlands Research.-. I CenterI /00 La1un mTmvuU'-' " Biological Report 82 (1 1.59) TR EL-82-4 July 1986 ~afayette,Louisiana 70506

Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (North Atlantic)

AMERICAN SHAD

Coastal Ecology Group Fish and Wildlife Service Waterways Experiment Station U.S. Department of the Interior U.S. Army Corps of Engineers Biological Report 82(11.59) TR EL-82-4 July 1986

Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (North Atlantic)

AMERICAN SHAD

Lori S. Weiss-Glanz, Jon G. Stanley, and John R. Moring Maine Cooperative Fish and Wildlife Research Unit 313 Murray Hall Uni versi ty of Maine Orono, ME 04469

Project Officer David Moran National Wetlands Research Center U.S. Fish and Wildlife Service 1010 Gause Boulevard Sl idel 1, LA 70458

Performed for Coastal Ecology Group Waterways Experiment Station U.S. Army Corps of Engineers Vicksburg, MS 39810

and

National Wet1 ands Research Center Research and Development Fish and Wildlife Service U .S. Department of the Interior Washington, DC 20240 This series should be referenced as follows:

U.S. Fish and Wildlife Service. 1983-19 . Species profiles: life histories and environmental requireme6 of coastal fishes and invertebrates. U.S. Fish Wildl. Serv. Biol. Rep. 82(11). U.S. Army Corps of Engineers, TR EL-82-4.

This profile should be cited as follows:

Weiss-Glanz, L.S. , J.G. Stanley, and J. R. Moring. 1986. Species profiles: 1i fe histories and environmental requirements of coastal fishes and invertebrates (North Atlantic)--American shad. U. S. Fish Wildl. Serv. Biol. Rep. 82(11.59). U.S. Army Corps of Engineers, TR EL-82-4. 16 pp. PREFACE

This species profile is one of a series on coastal aquatic organisms, principally fish, of sport, commercial, or ecological importance. The profiles are designed to provide coastal managers, engineers, and biologists with a brief comprehensive sketch of the biological characteristics and environmental requirements of the species and to describe how populations of the species may be expected to react to environmental changes caused by coastal development. Each profile has sections on taxonomy, 1ife history, ecological role, environmental requirements, and economic importance, if appl icabl e. A three-ring binder is used for this series so that new profiles can be added as they are prepared. This project is jointly planned and financed by the U.S. Army Corps of Engineers and the U. S. Fish and Wildlife Service.

Suggestions or questions regarding this report should be directed to one of the following addresses.

Information Transfer Specialist National Wetlands Research Center U.S. Fish and Wildlife Service NASA-Sl idell Computer Compl ex 1010 Gause Boulevard Slidell, LA 70458

U.S. Army Engineer Waterways Experiment Station Attention: WESER-C Post Office Box 631 Vicksburg, MS 39180 CONVERSION TABLE

Metric to U.S. Customary

To Obtain mil 1imeters (mn) inches centimeters ( an) inches meters (m) feet ki1 ometers ( km) mil es 2 square meters (m ) 10.76 square feet square ki 1meters ( km2) 0.3861 square miles hectares (ha) 2.471 acres

1 iters ( 1) gal 1ons cubic meters (m3) cubic feet cubic meters acre- feet mil 1igrams (mg) 0.00003527 ounces grams (g) 0.03527 ounces kilograms (kg) 2.205 pounds metric tons (t) 2205.0 pounds metric tons 1.102 short tons ki1 ocal ories ( kcal ) 3.968 British thennal units

Celsius degrees 1.8(OC) + 32 Fahrenheit degrees

U.S. Customary to Metric inches 25.40 mil 1 imeters inches 2.54 centimeters feet (ft) 0.3048 meters fa thoms 1.829 meters miles (mi) 1.609 kilometers nautical miles (mi) 1.852 ki1 oneters square feet (ft2) square meters acres 2 hectares square miles (mi ) square kilometers gal 1ons ( gal ) 1i ters cubic feet (ft3) cubic meters acre-feet cubic meters ounces (02) 28.35 grains pounds (lb) 0.4536 ki1 og rams short tons (ton) 0.9072 metric tons British thermal units (Btu) 0.2520 ki1 ocal ories Fahrenheit degrees 0.5556("F - 32) Celsius degrees CONTENTS

Page PREFACE ...... ii CONVERSION TABLE ...... iv TABLES ...... vi ACKNOWLEDGMENTS ...... vii NOMENCLATURE/TAXONOMY /RANGE ...... 1 MORPHOLOGY/IDENTIFICATION AIDS ...... 1 REASON FOR INCLUSION IN SERIES ...... 3 LIFE HISTORY ...... 3 Spawning ...... 3 Fecundity and Eggs ...... 4 Larvae to Adults ...... 4 Migration...... 5 AGE AND GROWTH ...... 6 COMMERCIAL/SPORT FISHERY ...... 6 History of the Fisheries ...... 6 Present Fishery ...... 7 Popu 1at i on Dynami cs ...... 8 ECOLOGICAL ROLE ...... 9 ENVIRONMENTAL REQUIREMENTS ...... 10 Salinity ...... 10 Temperature ...... 10 Oxygen ...... 11 Turbidity ...... 11 Substrate ...... 11 Depth ...... 11 Water Movement ...... 11 LITERATURECITED ...... 13 TABLES

Number Page

1 The percentage of first-time spawners in the Connecticut River spawning run ...... 4 The percentage of repeat spawners in American shad populations in Atlantic coast rivers...... 4 Lengths, weights, and ages, and the range of the number of eggs among individual American shad in the spawning populations of seven Atlantic coastal rivers of the U.S., 1951-59 ...... 4 Mean virgin and 1 ifetime fecundities of American shad populations in five Atlantic coast rivers ...... 5

Ages and corresponding average total lengths of shad in the Bay of Fundy ...... 6 Annual shad landings and values for the U. S. Atlantic coast ...... 7

Annual commercial landings of American shad for different regions along the U.S. coast, 1960-1983...... 8 Average instantaneous natural mortal ity rates of adults before and during Connecticut Yankee Atomic Power Plant operation ...... 9

Age structure of the American shad population in the Delaware River...... 9 ACKNOWLEDGMENTS

We thank Henry J. Rooke, Massachusetts Cooperative Fishery Research Unit, llniversity of Massachusetts; Richard Neves, Vi rginia Cooperative Fish and Wi ldlife Research Unit, Virginia Polytechnic Institute and State University; Christine Moffitt, Idaho Cooperative Fishery Research Unit, University of Idaho; and Stephen Rideout, U.S. Fish and Wildlife Service, for reviewi ng the manuscript . Figure 1. American shad, Alosa sapidissima.

AMERICAN SHAD

NOMENCLATURE/TAXONOMY/RANGE MORPHOLOGY/IDENTIFICATION AIDS

Scientific name . . Alosa sapidissima Body elongate, deep (its depth is (Wi 1son) 17%-19% of its total length [TL]) Preferred common name . . . .American strongly compressed 1aterally (Leim shad (Figure 1). 1924; Bigelow and Schroeder 1953; Other common names . . Shad, alose, Scott and C rossman 1973). Head common shad, Atlantic shad, North broadly triangular, 22%-24% of TL. River shad, Delaware shad, Sus- Gill membranes free from isthmus. Eye quehanna shad, white shad, buck moderate, adipose eye1 id we1 1 shad (males only), poplarback shad developed, diameter of eye 27%-32% of (Scott and Crossman 1973). head length (HL); snout moderate, Class ...... Osteichthyes length 27%-32% HL; interorbital width Order ...... Clupeiformes 19%-22% of HL. The anterior end of Family ...... Clupeidae the lower jaw not excessively thick or heavy, somewhat pointed, and fitting Geographic range: American shad are easily into a deep notch in upper jaw; anadromous. They are distributed jaws are about equal when the mouth is along the Atlantic coast from closed. The upper outline of the Newfoundland southward to F 1 ori da , lower jaw sli ghtly concave. Maxi1 lary and are most abundant from extending to posterior margin of eye. Connecticut to North Carol ina Teeth small, weak, and few in number (Figure 2). On the Pacific Coast, on premaxillary and mandible (lost the American shad was introduced completely in the adult) and absent on into the Sacramento and Columbia the roof of the mouth. Gill rakers on Rivers in 1871, and is now lower 1imb 59-73; branchiostegal rays established from southern Cal ifornia 7,7 (rarely 7,6). Fins soft rayed: northward to Cook Inlet, Alaska, and dorsal -1, hei ght moderate, base short, westward to the Kamchatka Peni nsu 1a 11%-13% of TL, rays 15-19, usually in Asia. 17-18; caudal, distinctly forked; A TL ANTIC OCEAN

MILES

KILOMETERS

Figure 2. Distribution of American shad in the North Atlantic region. anal-1, base length greater than probably has spawned in virtually dorsal base, 13%-14% of TL, height every accessible river and tributary shorter than dorsal height; rays along the Atlantic coast. 18-24, usual ly 20-22; pel vics, abdominal, small, length 9%-10% of TL, Shad spawn as early as mid- rays 9; pectorals, low on sides, November in Florida and as late as length 14%-15% of TL, rays 14-18, July in some Canadian rivers. The usually 16. Scales large, crenul ate males arrive at the spawning grounds on posterior margin, deciduous. before the females. The time of Lateral 1ine poorly developed with spawning migration is regulated by about 50-55 scales. Ventral scutes water temperatures in the river. well developed forming a sharp Spawning begins when the water sawbelly, prepelvic scutes 19-23, temperature reaches 12 "C (54 OF) and usually 20-22; postpelvic scutes continues as long as the temperature 12-19, usually 15-17. Vertebrae does not drop much below 12 OC (54 OF) 53-59, usual ly 55-58. Peritoneal or exceed 20 "C (68 "C). An increase 1i ni ng pal e; pyloric caeca numerous in temperature is the primary and usually clustered on right side. "trigger" for spawning, but Usually 4 to 6 black spots in photoperiod, flow velocity, and water horizontal row behind operculum. turbidity also are factors (Leggett Size: average length in fishery 380 and Whitney 1972). The spawning run mm; males 0.7 to 2.7 kg (1.5 to 6.0 peaks at a temperature of about 18 "C Ib); females 1.6 to 3.6 kg (3.5 to 8.0 (65 OF) and the range is 13 to 20 OC, lb), rarely to 5.4 kg (12 lb). or 56 to 68 OF (Walburg and Nichols 1967).

REASON FOR INCLUSION IN SERIES Spawning sites are the same from year to year. Shad spawn at night, Historically, the comnercial usually in shallow water with moderate fishery for American shad along the currents in the main stem of rivers Atlantic coast was widespread and (Marcy 1972). Spawning behavior has intense. The fishery now is generally been described by Medcof (1957) and reduced and important only in some Layzer (1976). A chase is probably waters. In rivers in the North involved; males following females in a Atlantic that still support spawning tightening circle. Spawners sometimes runs, the sport fishery is more splash at the surface. Eggs are important than the commercial fishery. released between sundown and midnight Federal and State agencies have in the open water where they are programs aimed at restoring American' fertilized by the males (Scott and shad to their former range and Crossman 1973). abundance. If these programs are successful, then protection or Most shad in the Connecticut mitigation of the shad must be River make their first spawning run considered in future coastal and when they are 4 or 5 years old (Table riveri ne devel opment projects. 1). Almost all shad 6 years old have spawned at least once.

LIFE HISTORY The percentage of shad that have spawned and return to spawn again Spawning (repeat spawners) increases from south to north. Shad native to rivers south The American shad is an of Cape Fear, North Carolina, appar- anadromous fish that 1i ves several ently die after spawning. In rivers years in the ocean and then returns to north of latitude 35 ON, some shad its natal river to spawn. The species survive, return to the ocean, and Table 1. The percentage of first-time spawn again the next year. Shad in spawners in the Connecticut River the north have a higher percentage of spawning run (Leggett 1976). repeat spawners than in the south (Table 2). Standard Fecundity and Eggs Age Mean deviation The American shad has a rela- tively high fecundity (Table 3), general ly decreasing from south to north (Table 4). Unfertilized eggs are 2 mn in diameter; fertilized, water-hardened eggs are 3 mn in diameter, semi buoyant, non-adhesi ve, and transparent, pale pink or amber Table 2. The percentage of repeat (Marcy 1976). The eggs are carried spawners in American shad populations along by the current and hatch in in Atlantic coast rivers (Leggett and about 8 to 12 days at 11 to 15 OC, or Carscadden 1978). 52 to 59 OF (Scott and Crossman 1973). Shad eggs hatched in only 3 days at Latitude Repeat temperatures of 14 to 23 OC (57 - River of river (ON) spawners(%) 73 OF) in the laboratory (Marcy 1976).

Mirami chi Larvae to Adults St. John Connecti cut Newly hatched larvae are about 7 Hudson mrn long and are planktonic (Marcy Susquehanna 1976). They are 12 mn long when the Potomac yolk sac is absorbed, and 25 to 28 mm York long and 2 to 3 weeks old upon James metamorphosis to the juvenile stage Neuse (Jones et al. 1978). The juveniles Edisto spend the first summer in the river. Ogeechee The morphologi cal characteristics of St. Johns larvae during development have been described by Jones et a1 . (1978). Table 3. Lengths, weights, and ages, and the range of the number of eggs (in thousands) among individual American shad populations of seven Atlantic coastal rivers of the United States, 1951-59 (Walburg and Nichols 1967).

River Fork Body Age Range of number length (mm) weight (kg) (years) of eggs (x 1,000)

Hudson 355-556 0.8-3.0 111-IX 116-468 Potomac 460-505 1.4-2.4 V-VI 267-525 Y ork 399-470 1.1-2.1 IV-VI 169-436 Neuse 447-498 1.8-2.7 IV-VI 423-547 Edisto 465-498 1.6-2.2 IV-VI 360-480 Ogeechee 457-475 1.7.-2.2 IV-VI 359-501 St. Johns (FL) 368-460 -0.6-1.8 IV-VI 277-659 - Table 4. Mean virgin and lifetime Mi grat ion fecundities of American shad populations in five Atlantic coast American shad along the Atlantic rivers (Leggett and Carscadden 1978). coast form common schools and under- take extensi ve ocean migrations - -- (Leggett and Whitney 1972). These Virgin Lifetime migrations are partly regulated by River fecundity fecundity changes in bottom water ternperatu res . American shad seem to prefer bottom St. Johns (FL) 406,000 406,000 temperatures between 3 and 15 OC (37 York (VA) 259,000 327,000 and 59 OF) and are most concentrated Connecticut (CT ) 256,000 384,000 at temperatures between 7 and 13 OC or St. John (NB) 135,000 273,000 45 and 55 OF (Neves and Depres 1979). Mi ramichi (NB) 129,000 258,000 Along the mid-Atlantic coast, shad move offshore to deeper water in winter (Talbot and Sykes 1958). In In the fall, juveniles (75 to 125 March and April, the schools move mm long) move to brackish water, then toward the coast. Shad returning to to the sea. Decreasing water rivers squth of Cape Hatteras follow temperature in the rivers is the the Gulf Stream, remaining in the 3 to primary stimulus for downstream 15 OC (37 - 59 OF) bottom isotherm. movement. Ju veni 1es mi grate seaward Shad migrating to north Atlantic first in northern rivers and rivers do so later in spring, progressively later in rivers to the following a route farther to sea south (Leggett 1977a). Juveni le shad because of preferred offshore start downstream in the St. Johns temperatures in the Middle Atlantic River, Florida, as the water cools to Bight. On the basis of tag returns, 15.5 "C or 60 OF (Walburg 1960). In some fish, however, mi grate north the Delaware River, shad begin moving along the coast (Neves and Depres downstream at a water temperature of 1979). 20.5 OC (69 OF); movements peak at 15.5 OC or 60 OF (Sykes and Lehman In summer and fall, shad 1957). Peak downstream migration is congregate in the Gulf of Maine and in late September and October in the the Bay of Fundy. This congregation Connecticut River, in late October in includes immature shad from Atlantic rivers tributary to Upper Delaware coast rivers and spawned-out adu 1ts Bay, and in late November in rivers from streams north of Chesapeake Bay. tributary to the Chesapeake Bay American shad migrate at the rate of (Leggett 1977a). 21 kmlday (13 milday) between Chesapeake Bay and the Bay of Fundy Shad remain in the ocean unti 1 (Leggett 1977a). They migrate up to mature. Males mature when 3 to 5 3,000 km (2,000 mi) in one season. years old; females mature when 4 to 6 years old (Leim 1924). The oldest The American shad homes to its shad examined in the Bay of Fundy was natal river to spawn. Dodson and 9 years old. The oldest shad in the Leggett (1974) believe homing is based United States was 11 years old and 584 on olfaction (smell) and rheotaxis mm long (Scott and Crossman 1973). (orientation to current) in the Con- The only self-sustaining, landlocked necticut River and probably elsewhere. population of American shad is in the The direction and goal of migration Mi 1lerton Reservoi r-San Juan River appears to be determined by olfaction system of California (Lambert et al. of chemicals, and the orientation 1980). along the migratory path is determined by tidal and river currents. The (FL) in mm for fish captured prior to orientation mechanism is sufficiently spawning at Lambertvi 1le on the robust that mi grations continue even Delaware River are W = 8.09 FL - 2335 after major changes in water flow, for males and W = 11.54 FL - 3764 for such as after the construction of females (Chittenden 1976). Valid headponds of hydroelectric facilities. ranges for 1inear interpolation were Homing is fairly precise but a few 330 to 520 mm for males and 410 to 550 individuals ascend rivers other than mm for females. Length-weight in their natal stream to spawn. relationships after spawning were W = 3.245 FL - 783 for males and W = 3.01 The timing of entry of shad into FL - 697 for females. Valid ranges rivers is highly dependent on water for linear interpolation were 265 to temperatures . The peak migration into 450 mm for males and 340 to 475 mm for freshwater thus is earlier in the females. The average total weight south than in the north. Runs peak in loss during the spawning run in the January in Florida and in June and Connecticut River was 45%-60% (Glebe July in New Brunswick and Quebec and Leggett 1981). Tissue loss was (Walburg and Nichols 1967; Leggett and greatest in small fish and in fish Whitney 1972). Shad migrate in the exposed to higher temperatures. Connecticut River at temperatures between 16.5 and 21.5 OC (62 and Wilk et a1 . (1978) calculated the 71 OF). American shad tend to discon- relation of weight in grams to total ti nue upstream movement at tempera- length in millimeters to be log tures greater than 20 OC (68 OF) W = -5.3994 + 3.2255 log TL, for 294 (Kuzmeskus 1977). shad collected in the New York Bight. No significant difference between the Shad spawn far enough upstream sexes was observed. for eggs to drift and hatch before reaching saltwater. Low water temperatures in the spring may delay COMMERC IAL/SPORT FISHERY gonadal maturation, resulting in a 1onger period of upstream migration History of the Fisheries prior to spawning (Marcy 1976). These migrations may extend as far as 800 km During the 19th century, (500 mi) inland. The maximum distance extensive fisheries for shad developed in most rivers is now limited by along the entire Atlantic coast. Shad natural and human-made obstructions.

AGE AND GROWTH Table 5. Ages and corresponding average total lengths of shad in the Age and growth can be evaluated Bay of Fundy (Leim 1924). by exami ning scale structures . Judy (1961) verified the scale method of aging American shad, and also observed a mark on the scale that formed when Growing Length the juvenile left fresh water. Shad season Age group (m) grow about 100 mm per year until sexually mature, when growth slows (Table 5). American shad live 5 to 7 years and may reach a weight of 1 to 3 kg* The re1at ions between total weight (W) in grams and fork length were captured in rivers and in coastal Table 6. Annual shad landings waters. Major gear developed and pre- (thousands of pounds) and value ferred in different locations were (thousands of dollars) for the U.S. drift and staked gill nets, pound Atlantic coast (Wal burg and Nichols nets, haul seines, weirs , fyke nets, 1967). bow nets, and dip nets. The estimated Atlantic coast catch in 1896 was 50 mi 11 ion pounds (23,000 t), but between Year Weight Value 1930 and 1960, the annual catch was 995 about 10 million pounds (Table 6). 1880 18,068 --- Since 1960, the catch has declined 1887 29,630 further, principally due to dams, 1888 33,397 1,665 1,651 pollution, and overfishing. The 1896 50,499 Atlantic coast catches are greatest in 1908 25,935 2,092--- Chesapeake Bay (Table 7). 1929 13,955 1930 10,373 --- Present Fishery 1931 11,336 - - - 1932 9,272 --- 860 In New England, the principal 1935 8,236 - - - American shad fishery is on the 1937 9,647 --- Connecticut Rivery where a small 1938 9,720 --- commercial fishery and sport fishery 1939 10,075 exist. About 3,000 1b (1.4 t), were 1940 9,964 905 landed in Massachusetts in 1979. 1945 14,699 2,500 Merriman (1970) gave capitalized an- 1950 8,223 1,596--- nual value to the Connecticut River of 1951 8,477 --- $75 million for the commercial fishery 1952 10,521 --- and $14 million for the sport fishery. 1953 7,799 1954 8,668 --- In Maine, about 95% of the river 1955 8,599 1,422 habitat once used for spawning is now 1656 9,672 --- blocked by inpassable dams (Flagg et 1957 11,369 --- al. 1979). Shad runs in Maine are 1958 8,186 --- estimated at no more than several 1959 8,200 1,086 thousand fish annually and no more 1960 8,134 1,107 than 100 to 600 adult shad are caught in a small sport fishery. A fishery specific for American shad is non-existent ; catches are incidental fishery in marine waters for American to those of other species. If shad is restricted, but in freshwater restoration is completed as planned, a the limit is six fish per day. possible annual harvest of 1.5 mi 11 ion pounds (680 t) is projected. If ade- The commercial fishery in the quate fish passage facil ities2are con- Connecticut River employs drifting structed, 6,OQ)I to 10,000 mi (15,000 gill nets at night, mainly in the to 25,000 km ) of additional river river below Hartford. Some fishing would be available to shad. occurs during the day when the water is especially turbid. Fyke, trap, or New Hampshire currently has no pound nets are now a1 lowed in the commerci a1 regu 1ati ons for shad; river during the shad run. The however, there is a two fish per day primary market is for roe (eggs). bag limit for hook and line fishermen. Males (buck shad) have little value. Connecticut carefu 1 ly regu 1ates Massachusetts has banned commer- commercial fishing for shad on the cial fishing for shad. The sport Connecticut River. The season is open Table 7. Annual commercial landings (x 1,000 lb) of American shad for different regions along the U.S. coast, 1960-1983. Code: NE = New England, MA = Mid-Atlantic, CB = Chesapeake Bay, SA = South Atlantic, PC = Pacific Coast (1960-1977 National Marine Fisheries Service, Statistical Digest; 1978-1983 National Marine Fisheries Service, unpublished data).

Coastal region

Year NE MA CB SA PC

1960 432 1,237 2,682 1,614 456 1961 547 1,026 3,144 1,612 927 1962 470 84 1 3,795 2,167 1,586 1963 325 7 44 3,139 1,734 1,503 1964 320 721 3,541 1,687 818 1965 380 635 4,298 2,379 870 1966 27 9 379 3,564 1,736 1,347 1967 7 54 387 3,005 1,562 1,333 1968 218 379 3,508 2,052 862 1969 201 342 3,540 1,904 610 1970 186 314 5,151 1,851 724 197 1 283 222 2,473 1,452 499 1972 264 375 3,014 1,091 709 1973 261 308 3,033 685 483 1974 257 294 1,789 655 5 11 197 5 208 337 1,321 518 522 1976 412 322 1,006 320 48 1 1977 418 3 94 1,547 418 560 1978 36 1 245 1,322 976 545 1979 3 30 216 1,041 36 3 797 1980 253 406 998 839 277 1981 6 6 510 500 1,235 120 1982 40 3 7 57 590 1,033 42 9 1983 504 36 5 242 1,974 413

to commercial fishing from April 1 to Conn. Dep. Environ. Prot.; pers. June 15. During the season, fishing corn.). is prohibited from Friday sunset to Sunday sunset. Monof i1 ament gi 11 nets Sportfishing for shad in are prohibited and the gill nets used Connecticut is permitted from April 1 must have a minimum stretch of 5 to a published closing date determined inches (127 mm). There are no size or each year. In streams, angling and sex restrictions and a commercial scoop nets are permitted; the bag fishing license is required. Catch limit is six fish per day. information is reasonably accurate because 1i cense holders must complete a report of fishing at the end of each Population Dynamics season, and Connecticut biologists have validated this method of report- The population dynamics of ing catch statistics (Eric Smith, American shad in the Connecticut River is similar to other fishes with high The Delaware River shad fecundity (Leggett 1976; Leggett population was made up mostly of Age 1977b; Marcy 1976). About 64% of the IV males and Age VI females (Table 9). annual variation in the production of Males first appeared in the runs at juvenile shad was directly related to Age I11 whereas females first appeared the1 number of spawners in the spring at Age IV. Few males Age VI and run; 22% of the variation was attri- females Age VII were observed buted to water tenperature and flow (Chi ttenden 1975). characteristics during the run (Marcy 1976). ECOLOGICAL ROLE The rate of exploitation was a major factor influencing the number of The diet of juvenile American fish in the spawning run in the shad in freshwater is diverse; insects Connecticut River (Leggett 1976). The and crustaceans are most common fishery removed significant numbers of (Wal burg 1960). Early larvae feed adults just prior to spawning, and mostly on cyclopoid copepods and because the eggs are the most tendipedi ds (Levesque and Reed 1972). desirable fish product, fully mature Juveniles eat food in the water col- females are the principal targets of umn, not on the bottom, and Domermth the fishery. and Reed (1980) reported that juvenile shad were selective of what they ate; The number of adults that survive the diet consisted of 20% bosminids the fishery are directly correlated and 51% daphnids. with the number of fish produced in the next generati on. This After going to sea, the American relationship is described by a shad feeds on a variety of small stock-recruitment equation: crustacea, many of which are 0.7 (1 - N/87) associated with the bottom. Mysids R=Ne dominate their diet in the Bay of where R is recruitment and N is the Fundy (Leim 1924). Adults also feed parent stock in terms of numbers of on copepods, small fishes, euphausids, eggs (Leggett 1976). fish eggs, and amphipods (Bigelow and Average instantaneous natural mortality of spawners was less after the Connecticut Yankee Atomic Power Table 9. Age structure of the Plant began operation (Table 8). American shad population in the Delaware River (Chittenden 1975).

Table 8. Average instantaneous Sex Age Number % natural mortality rates of adults (standard deviations in parentheses) Ma 1es before and during Connecticut Yankee II Atomic Power Plant operation (Leggett I11 1976). Iv v Instantaneous mortality VI Pre-operation Operation Fema 1es 1965-1967 1968-1973 Iv Sex v Males 1.5(1.2) 0.7(0.6) VI Females 1.2(0.7) 0.7(0.4) VI I Schroeder 1953; Scott and Crossman American shad eggs are always 1973). Shad probably have a diel deposited in freshwater but whether vertical migration to follow the diel they hatch only in freshwater, only in migration of their principal food, brackish water, or in both is not zooplankton (Neves and Depres 1979). certain. An experiment reported by Leim (1924) showed that eggs and A1 though investi gators be1 ieve larvae can tolerate brackish water of that few shad feed in freshwater, 7.5 to 15 ppt, but not 22.5 ppt. He American shad placed in a freshwater also reported that hatching success of pond fed on artificial feed (Atkinson eggs was higher in brackish and full 1951). strength seawater than in freshwater, but the findings were based only on Predators take large numbers of nine eggs. American shad in both freshwater and the sea. Juvenile shad in rivers are Temperature eaten by juvenile bass (Morone saxatilis), American eels (An uilla Most shad spawn in rivers at rostrata), and birds. At sea,9T adu t water temperatures of 12 to 18 OC, or shad fall prey to seals, sharks, 54 to 64 OF (Leggett and Whitney bluefin tuna (Thunnus th nnus) 1972). Leim (1924) claimed that tingf ish (Scomberomorus regahni American shad eggs hatch in 12 to 15 porpoises (Scott and Crossman 1973). days at 12 OC (54 OF) and 6 to 8 days None of these predators depend solely at 17 OC (63 OF). He also noted that on shad for food; in fact, shad appear eggs cease developing at 7 OC (45 OF), to be of minor importance as food in and abnormalities develop at 22 OC rivers or the ocean. (72 OF). Leim used the same experimental design descri bed in the The American shad has the usual salinity section, except that complement of parasites and diseases. freshwater was used for the Acanthocephala, parasitic copepods, temperature experiments. distomes , nematodes, and trematodes have all been reported in or on shad. The American shad avoids cold The sea lamprey (Petrom zon mari nus) water when possi ble. The lower and freshwater 1ampreys + Ichthyomyzon thermal tolerance limit is about 2 OC sp.) have been observed attached to (36 OF); p'rolonged exposure to 4 to adult shad in the Connecticut River 6 OC (39 to 43 OF) is sublethal and (Wal burg and Nichols 1967). too cold for full body functioning (Chittenden 1972). When given a choice, young shad avoid temperatures ENVIRONMENTAL REQUIREMENTS below 8 OC (46 OF) and stringently avoid temperatures below 5 OC (41 OF). Sal inity Chittenden concluded that cold water re1eased be1 ow reservoi rs may The American shad is euryhaline adversely affect spawning and nursery and adapts readily to either fresh- areas downst ream. water or seawater during its anadromous migrations. The adults require 2 American shad also avoid rapid or 3 days to adapt to freshwater as increases in temperature. Tests in evidenced by their wandering in tanks showed that shad avoided tem- estuaries before entering the rivers perature increases of about 4 OC (Leggett 1976). The transfer of adult (7 OF) above the acclimation shad from seawater to freshwater over temperature (Moss 1970). Juveni 1es a 2.5-h period caused physiologic did not avoid changes of 1 OC (2 OF), stress and high mortality (Leggett and suggesting a sensory threshold of 0'Boy1 e 1976). between +1 and +4 OC (+2 and +7 OF) above ambient temperatu re. Shad in the water column and the eggs are attempt to avoid potential ly lethal carried downstream. Shad have been temperatures. Field observations bear observed to spawn over sand, silt, out these laboratory findings. muck, gravel, and boulder substrate (Mansueti and Kolb 1953; Walburg 1960; Migrations in the ocean and Leggett 1976). freshwater are closely tied to water temperature. Shad are most frequently Depth caught commerci a1 ly in ocean bottom temperatures of 7 to 13 OC (45 to 55 Depth is not a critical factor to OF) (Neves and Depres 1979). the American shad. Fish in spawning runs are caught at all depths. For Oxygen example, Mansueti and Kol b (1953), Walburg (1960), and Kuzmeskus (1977) The American shad lives in well reported fish spawning at depths from oxygenated envi ronments in rivers and 0.45 to 7 m (1.5 to 23 ft). in the sea. Dissolved oxygen concentrations must be 4 to 5 mgll Juveniles live at depths of 0.9 (ppm) in headponds through which shad to 4.9 m (3 to 16 ft) in the pass in thei r migration (Jessop 1975). Connecticut River (Marcy 1976). The Chittenden (1969) reports that at abundance was related more to distance dissol ved oxygen concentrations below upstream rather than to depth. During 3 mgll, equilibrium Is lost, at the day, 87% of the juvenile shad concent rations be1ow 2 mgll , heavy caught in a gillnet were near the mortality occurs, and at less than 0.6 bottom at depths of 3.7 to 4.9 m (12 mgll, all fish die imediately. Shad to 16 ft). At night all were caught eggs were absent where dissolved near the surface. oxygen was lower than 5 mgll (Marcy 1976). Carlson (1968) reports the At sea, shad are near the bottom oxygen LCs0 for Connecticut River shad during the day and disperse throughout eggs is 2.0 to 2.5 mg/l. the water column at night (Neves and Dep res 1979) . Turbidi t.

Tal bot (1954) concluded that Water Movement extens ive dredgi ng of the Hudson R i ver produced no measurable adverse effects Water velocity is critical on shad abundance. Adult shad readily because shad must negotiate river enter the Shubenacadie River in Nova currents and f ishways when migrating Scotia, where turbidity is 1 g/l (Leim upstream and must go over spillways 1924). As part of a laboratory when swimmi ng downstream. Adult shad assessment, Auld and Schubel (1978) migrating upstream are reluctant to reported that suspended sediment use older, traditional f ishways, concentrations up to 1 gll did not because entrance widths, depths, and significantly affect hatching success; flows are often unsuitable (Wal burg however, concentrations greater than and Nichols 1967). Pool-and-wei r and 0.1 g/l for 96 h significantly reduced vertical-baffle fishways and elevators the survival of shad larvae. Larvae are much more efficient. For the therefore are much less tolerant of pool -and-wei r fishway, optimum suspended sediments than eggs. difference in pool elevations is 23 cm (9 in) when water velocities are 61 to Substrate 91 cmlsec (2 to 3 ftlsec). For any fish passage to work, sufficient water Substrate type apparently is volume and velocity at the entrance is unimportant to shad because fish spawn essential. In the Connecticut River the daily movement of shad upstream passed through a 850 kw Ossberger was 4.6 km (2.9 mi) in brackish water, turbine were killed outright; those and 14 km (9 mi) in freshwater that survived died later of stress and (Leggett 1976). predation, or from the delayed effects of scale loss or injuries caused by Adult downstream mi grat ion the fishway itself. At Mactaquac, New depends on water currents and the Brunswick, Jessop (1975) found that at pattern of currents around obst ruc- least 25% of the shad died as a result tions. The rate of flow into a of physical stress caused by a fish- fishway accounted for 60% of the lift. Jessop (1975) also reported that variation in the number of downstream exposure to lethal nitrogen super- migrants in a f ishway (Moff itt 1979). saturation in waters below dams may Without attractant flow, no fish cause mortal ity. entered the fishway. Fish that fail to find the downstream passage must American shad spawn at water pass over the spillway or through velocities of 10 to 132 cmlsec (

Atkinson, C.E. 1951. Feeding habits American shad, Alosa sa idissima, of shad (Alosa sapidissima) in in the Delaware--P-pha. River fresh water. Ecology 32: 556-557. dissertation. Rutgers University, New Brunswick, N. J. 458 pp.

Auld, A.H., and J.R. Schubel. 1978. Chittenden, M.E., Jr. 1972. Responses Effects of suspended sediment on fish eggs and larvae, a of young American shad, Alosa 1aboratory assessment. Estuarine sapidissima, to low temperatures. Coastal Mar. Sci. 6: 153-164. Trans. Am. Fish. SOC. 101: 680-685.

Bigelow, H.B., and W.C. Schroeder. 1953. Fishes of the Gulf of Chittenden, M.E., Jr. 1975. Dynamics Maine. U.S. Fish Wildl. Serv. of American shad, Alosa Fish. Bull. 53. 577 pp. sapidissima, run in the Delaware River. U.S. Natl. Mar. Fish. Serv. Fish. Bull. 73:487-494. Bureau of Commercial Fisheries. 1965a. New England Fisheries. U.S. Fish and Wildl. Serv. Bur. Comer. Chittenden, M.E., Jr. 1976. Weight Fish. Stat. No. 4330 (and other loss, mortality, feeding and issues unti 1 1976). duration of residence of adult American shad, Alosa sapidissima, in fresh water. U.S. Natl. Mar. Bureau of Commercial Fisheries. 1965b. Fish. Serv. Fish. Bull. Massachusetts Landings. U.S. Fish 74: 151-157. and Wildl. Serv. Bur. Commer. Fish. Stat. No. 4140 (and other issues until 1979). Dodson, J.J., and W.C. Leggett. 1974. Role of olfaction and vision in the behavior of American shad Carlson, F.T. 1968. Report on the (Alosa sapidissima) homing to the biological findings. Pages 4-41 Connecticut River from Long Island Sound. J. Fish. Res. -in Suitabi 1ity of the Susquehanna River for restoration of shad. Board Can. 31:1607-1619. U.S. Fish Wildl. Serv., Board of Nat. Resour., N.Y. Dep. Conserv., and Penn. Fish. Comm. Domermuth, R.R., and R.J. Reed. 1980. Food of juveni 1e Ameri can shad, Alosa sapidissima, juvenile Chittenden, M.E., Jr. 1969. Life blueback herring, Alosa history and ecology of the aest ival is, and pumpkinseed, Lepomi s gibbosus, in the Kuzmeskus, D.M. 1977. Egg production Connecticut River below Holyoke and spawning site distribution of Dam, Massachusetts. Estuaries the American shad, Alosa 3: 65-68. sapidissima, in the Holyoke Pool, Connecticut River, Massachusetts. Flagg, L., T.S. Squires, and L. M.S. Thesis. University of Austin. 1979. American shad Massachusetts, Amherst. 134 pp. management plan. Maine Department of Mari,ne Resources, Lambert, T.R., C.L. Toole, J.M. Augusta. Handley, M.A. Koeneke, D.F. Mitchell, and J .C .S. Wang. 1980. Glebe, B.D., and W.C. Leggett. 1981. Envi ronmental conditions Tempora 1, int ra-popu 1ati on associated with spawning of a differences in energy a1 location 1andlocked American shad, Alosa and use by American shad (Alosa sapidissima, population. Am. sapidissima) during the spawning Zoo1 . 20:813. (Abstr.) migration. Can. J. Fish. Aquat. Sci . 38: 795-805. Layzer, J .B. 1976. Spawning sites and behavior of American shad, Alosa Gloss, S.P. 1982. Estimates of sapidissima (Wilson), in the juvenile American shad (Alosa Connecticut River between Holyoke sapidissima) turbine mortality at and Turners Fa1 ls, Massachusetts, 1ow-head hydropower sites . Page 1972. M.S. Thesis. University 22 in R.G. Howey, ed. of Massachusetts, Amherst. 46 pp. Proceeangs of 1981 American shad workshop -- culture, transporta- Leggett, W.C. 1976. The American shad tion and marking. U.S. Fish (Alosa sapidissima), with special WiId1 . Serv. , Lamar Inf. Leaf 1. reference to its migration and 82-01. population dynamics in the Connecticut River. Am. Fish. Jessop, B.M. 1975. A review of Soc. Monogr. 1: 169-225. the American shad (Alosa sapidissima) stocks of the St. Leggett , W .C . 1977a. Ocean mi gration John River, New Brunswick, with rates of American shad (Alosa particular references to the sa idissima). J. Fish. Res. adverse effects of hydroelectric 8%-oard an. 34: 1422-1426. developments. Can. Fish. Mar. Serv. Resour., Dev. Branch Mar-T. Leggett, W.C. 1977b. Density Reg. Tech. Rep. Ser. Mar./T. dependence, density independence, 75-6: 1-23. and recruitment in the Ameri can shad (A1 osa sapi dissima) Jones, P.W., F.D. Martin, and J.D. population of the Connecticut Hardy, Jr. 1978. Development of River. Pages 3-17 in Proceedings fishes of the Mid-Atlantic Bight. of conference on Zsessina the An atlas of egg, larval and effects of power plant induced juvenile stages. Vol . I. U.S. mortality on fish population., Fish Wildl. Serv. Biol. S e r v . U. S. Environmental Protection Program FWS/OBS-78/12. Agency, Gat1 inburg, Tenn.

Judy, M.H. 1961. Validity of age Leggett, W.C., and J.E. Carscadden. determinations from scales of 1978. Latitudinal variation in marked American shad. U.S. Fish reproductive characteristics of Wildl. Serv. Fish. Bull. 61: American shad (A1 osa 161-170. sapidissima): evidence for populations specific life history strategies in fish. J. Fish. Merriman, D. 1970. The calefaction of Res . Board Can. 35: 1469-1478. a river. Sci. Am. 222:42-54. Leggett, W.C., and R.N. O'Boyle. 1976. Moffitt, C.M. 1979. Recolonization of Osmotic stress and mortality in American shad, Alosa sapidissima adult American shad during (Wi lson) , above~ainbow Dam transfer from saltwater to fish-ladder, Farmington River, freshwater. J. Fish Biol. Connecticut. Ph .D. Thesis, 8: 459-469. Uni versi ty of Massachusetts, Amherst. 128 pp. Leggett, W.C., and R.R. Whitney. 1972. Water temperature and the Moss, S.A. 1970. The responses of migrations of 4merican shad. young American shad to rapid U.S. Natl. Mar. Fish. Serv. temperature changes. Trans. Am. Fish. Bull . 70: 659-670. Fish. Soc. 99:381-384. Leim, A.H. 1924. The life history of National Marine Fisheries Service. the shad (Alosa sapidissima) 1980. Fisheries Statistics of (Wi lson) with special reference the United States-1976. U .S . to the factors limiting its Department of Comerce, abundance. Biol . Board Can., Washington, D.C. (and similar Contri b. Can. Biol . 2: 163-284. earlier volumes). Levesque, R.C., and R.J. Reed. 1972. Neves, R .J., and L. Depres. 1979. The Food availability and consumption oceanic mi qration of American by young Connecticut River shad shad, ~losasapidissima, along ~iosasapidissima. 3. Fish. Res. the Atlantic coast. U.S. Natl. Board Can. 29: 1495-1499. Mar. Fish. Serv. Fish. Bull. 77: 199-212. Mansueti, R.J., and H. Kolb. 1953. A historical review of the shad Scott, W.B., and E.J. Crossman. 1973. fisheries of North America. Freshwater fishes of Canada. Chesapeake Bi 01 ogi cal Laboratory , Fish. Res. Board Can. Bull. 184. Solomons, Md. Publ. 97. 293 pp. 966 pp.

Marcy, B.C., Jr. 1972. Spawning of Sykes, J.E., and B.A. Lehman. 1957. the American shad, Alosa Past and present Delaware River sa idissima, in the lower shad fishery and considerations k River. Chesapeake for its future. U.S. Fish Wild. Sci . 13:116-119. Serv. Res. Rep. 46. 25 pp. Marcy, B.C., Jr. 1976. Early life Talbot, G.B. 1954. Factors history studies of American shad associated with fluctuations in in the lower Connecticut River abundance of Hudson River shad. and the effects of the U.S. Fish Wildl. Serv. Fish. Connecticut Yankee Plant. Am. Bull. 54: 373-413. Fish. Soc. Monogr. No. 1:141-168. Talbot, G.B., and J.E. Sykes. 1958. Atlantic coastal migrations of Medcof, J.C. 1957. Nuptial or American shad. U.S. Fish Wildl. ~renu~tialbehavior of the shad, Serv. Fish. Bull. 58:473-490. ~losa' sa idissima (~ilson). Copeia 1957-2-253. Copei a Wal burg, C.H. 1960. Abundance and 1957 (3): 252-253. life history of the shad, St. Johns River, Florida. U.S. Fish Wildl. Serv. Fish. Bull. Wildl. Serv. Spec. Sci. Rep. 60 :487 -501. Fish. 550. 105 pp.

Walburg, C.H., and P.R. Nichols. 1967. Wilk, S.J., W.W. Morse, and D.E. Ri01 ogy and management of the Ralph. 1978. Length-wei ght American shad and status of the re1ati onshi ps of fishes collected fisheries, Atlantic coast of the in the New York Bight. Bull. United States, 1960. U.S. Fish N.J. Acad. Sci. 23:58-64. 50272 -101 3. Recluient's Accession NO. REPORT DOCUMENTATION I '. REWRT 2. 1 PAGE I Biological Report 82(11.59)*1 4. Title and Subtitle 5. Report Date Species Profiles: . Life Histories and Environmental Requirements Ju 1y 1986 of Coastal Fishes and Invertebrates (iiorth Atlantic) -- American 6. Shad 7. Author($) 8. Pbdormins Orsanization Rept. NO. L.S. Weiss-Glanz, Jon G. Stanley, and John R. Moring 9. Performing Organizat~onName and Addreas 10. Pmlbct/Task/Work Unit No. Maine Cooperative Fish and Wild1 ife Research Unit 313 Murray Hall, University of Maine Orono, ME 04469

12. Swnrortng Or~anizat!onName and Address National Wetlands Research Center U.S. Army Corps of Engineers Fish and Wildlife Service Waterways Experiment Station U.S. Dep. of the Interior P.O. Box 631 Washington, DC 20240 Vicksburg, MS 39180

I 15. Supplementaw Notes *U.S. Army Corps of Engineers Report No. TR EL-82-4.

16. Abstract (Urnit: 200 words)

Species profiles are 1iterature summaries on the taxonomy, morphology, distribution, 1ife history, and environmental requirements of coastal aquatic species. They are designed to assist in environmental impact assessment. After a drastic decline in abundance, the American shad (Alosa sapidissima) is being restored in many of the rivers along the East Coast that originally supported large runs. The American shad is an anadromous fish that lives several years in the ocean and returns to its natal river to spawn in the spring when temperatures reach 12OC. The eggs are carried by currents downstream from spawning sites in large rivers for 8-12 days until they hatch. The larvae, which metamorphose to the juvenile stage in 3-4 weeks, remain in the river until fall when they migrate to the sea. Shad move offshore and southward during winter at water temperatures of 3-15°C. American shad feed or zooplankton. They adapt readily to fresh - or saltwater, but they prefer salinities

17. Oosument Analyais b. Oesc~ptors Estuaries Sal ini ty Animal migrations Fishes Temperature Suspended sediments Growth Fisheries Rivers Feeding habits Life cycles b. IdmtlRen/O~en-Ended Tarma American shad Alosa sapidissima Spawning Habitat

18. Ava8labil~tyStatement I 19. Securnty Class (Tho, Reuort) 21. No. of Pages 16 Unl imited Re1 ease I Unclassified (See ANSI-239.16) OPTIONAL FORM 272 (4-77) (Formerly NTIS-35) Department of Commerce REGION 1 REGION 2 REGION 3 Regional Director Regional Director Regional Director U.S. Fish and Wildlife Service U.S. Fish and Wildlife Service U.S. Fish and Wildlife Service Lloyd Five Hundred Building, Suite 1692 P.O. Box 1306 Federal Building, Fort Snelling 500 N.E. Multnornah Street Albuquerque, New Mexico 87 103 Twin Cities, Minnesota 55 1 1 1 Portland, Oregon 97232

REGION 4 REGION 5 REGION 6 Regional Director Regional Director Regional Director U.S. Fish and Wildlife Service U.S. Fish and Wildlife Service U.S. Fish and Wildlife Service Richard B. Russell Building One Gateway Center P.O. Box 25486 75 Spring Street, S.W. Newton Corner, Massachusetts 02158 Denver Federal Center Atlanta, Georgia 30303 Denver, Colorado 80225

REGION 7 Regional Director U.S. Fish and Wildlife Service 101 1 E. Tudor Road Anchorage, Alaska 99503 TAKE PRIDE inAmerzcd DEPARTMENT OF THE IWTERIOR U.S. FISH AND WllDLlA SERVICE

As the Nation's principal conservation agency. the Department of the Interior has responsibility for most of our .nationally owned public lands and natural resources. This includes fostering the wisest use of our land and water resourcm, protecting our fish and wildlife, preserving thsenvironmental and cultural values of our national parks and historical places, and providing for the enjoyment of life through outdoor recreation. The Department as- sesses our energy and mineral resources and works to assure that their development is in the best interests of all our people. The Department also has a major responsibility for American Indian reservation communities and for paople who live in island territories under U.S. administration.