COMPARATIVE STUDY OF POPULATIONS OF THE STRIPED BASS Marine Biological Laboratory OCT 1 5 1957 WOODS HOLE, MASS. SPECIAL SCIENTIFIC REPORT- FISHERIES No. 204 UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE EXPLANATORY NOTE The series embodies results of investigations, usually of restricted scope, intended to aid or direct management or utilization practices and as guides for administrative or legislative action. It is issued in limited quantities for official use of Federal, State or cooperating agencies and in processed form for economy and to avoid delay in publication . United States Department of the Interior, Fred A. Seaton, Secretary U.S. Fish and Wildlife Service COMPAEIATIVE STUDY OF POPULATIONS OF THE STRIPED BASS By Robert Minturn Lewis Fishery Research Biologist Special Scientific Report -Fisheries No. 204. Washington, D. G. June 1957 ABSTRACT This study was undertaken in an effort to determine the value of gill raker counts as a taxonomic tool in classifying populations of striped bass, Roccus saxatilis. The possibility of a change with age and a difference between sexes in the number of gill rakers was investigated. Specimens were available from Philip River, Miramichi River, St. Lawrence River, coastal Rhode Island, Long Island Sound, Hudson River, Mullica River, Delaware River, Chesapeake Bay, Albemarle Sound, Pamlico River, Cape Fear River, Santee- Cooper River System, Gulf of Mexico and California. Gill raker counts were subjected to the following statistical procedures: t-test, analysis of variance, analysis of co- variance, chi-square and regression. The tests showed that there was no change in the number of gill rakers in the first two years of growth and that there was no significant difference in the number of gill rakers between males and females. On the basis of gill raker counts only, specimens from the Santee- Cooper River System, South Carolina were considered as one population; this was also true for specimens from the Hudson River, New York. The Chesapeake Bay population was divided into three main subpopulations . Samples from Long Island Sound were intermediate between those of Chesapeake Bay and the Hudson River. Specimens from California and the Hudson River had high counts and those from the Delaware River approached those from the James River in the Chesapeake Bay. It was shown that gill raker counts could be used to separate populations of striped bass . CONTENTS Page Literature review 1 Materials examined 2 Methods 5 Results 5 Variation in number of gill rakers with age 5 Variation in number of gill rakers with sex 6 Populations 6 Chesapeake Bay 6 Above and below Pinopolis Dam, S.C 7 Hudson River 8 Comparison of James and Hudson Rivers 9 Long Island Sound 9 Comparison of those from California with those from Chesapeake Bay and Hudson River 9 Comparison of those from Canada, Delaware River, and Albemarle Sound 10 An overall comparison 10 Discussion 11 Summary and conclusions 13 Literature cited 14 COMPARATIVE STUDY OF POPULATIONS OF THE STRIPED BASSi/ This stady was instituted to determine whether gill rakers were a valid taxonomic tool that could be used along with other meristic characters to classify populations of striped bass, Roccus saxatilis (Walbaum). Racial studies of the striped bass have been made by Merriman (1937 and 1941), Vladykov and Wal- lace (1952), Raney and de Sylva (1953), Raney, Woolcott, and Mehring (1954), Raney and Wool - cott (1955), and Raney (ms.). The striped bass is found along the At- lantic coast from the St. Lawrence River to the northern part of Florida. It also occurs in the Gulf of Mexico from the west coast of Florida to Louisiana. Striped bass from northern New Jersey were shipped to California in 1879 and 1881 and are now well established there. The striped bass is economically im- portant in most parts of its range. It is there- fore necessary, as an aid to management of this species, to know where populations occur and how to separate them from other populations that exist in close proximity. This gill-raker study was conducted, along with many other past and present racial studies, to help achieve this end. The writer wishes to express his appre- ciation to Dr. Edward C. Raney of the Depart- ment of Conservation for his guidance during the course of this study. He also wishes to thank Dr . Clifford O . Berg of the Department of Entomology and Limnology for his criticism of the manuscript. Dr. R.G.D. Steel and Dr. Douglas Robson gave valuable statistical advice. LITERATURE REVIEW Vladykov and Wallace (1952) working with the striped bass from the Atlantic coast, maintained that gill rakers were not a useful character for racial determination because they thought they varied with age . Other workers have used gill-raker counts in taxonomic studies. Vladykov and Beaulieu (1951), working with the sturgeon in the Province of Quebec, found that the young of Acipenser fu Ivescens have their gill rakers closer together than the adults. This is explained by the fact that the development of the gill rakers is already completed in the case of the young, while growth of the gill arch con- tinues through the rest of the life of the fish. TTiey worked with three species of Eastern North American sturgeon and concluded that the number of gill rakers on the first branchial arch is a very important taxonomic character. SuSrdson (1952), studying coregonid fishes in Sweden, considered that environment affects the number of gill rakers very slightly or not at all. Hildebrand and Schroeder (1928) found that the number of gill rakers of Alosa sapidiffiima change with age. Vladykov (1954) thought that the number of gill rakers were of very little value as a character for chars (Salvelinus) . Working with the berycoid fish family Polymixiidae, Lachner (1955), found that the number of dorsal fin rays and the total num- ber of gill rakers were the most critical char- acters in the separation of the species. Ginsburg (1955), in his study of the genus Bembrops, also used gill rakers as an important meristic char- acter. McGregor (1924) used a combination of gill rakers, pyloric caeca, branchiostegals, ova, and vertebrae to separate races of king salmon from the Klamath and Sacramento Rivers in California . Gill rakers have been used as a taxonom- ic character at all levels of differentiation, generic, specific, subspecific, and race . \l A thesis presented to the faculty of the Graduate School of Cornell University for the degree of Master of Science . McHug^'s (1951) study of the meristic variations of Engraulis mordax mordax showed a gradual increase in the number of gill rakers in larger fish. He was able to demonstrate by statistical treatment among three localities, that ranged from British Columbia to Baja California, that there were highly significant differences among localities and between sexes within each locality . MATERIAL EXAMINED The collections examined are listed from north to south along the Atlantic Coast; California specimens are listed at the end. The abbreviations used are C.U., Cornell Universi- ty; U.S.N.M., United States National Museum; U. Md., University of Maryland; N.C.S.C, North Carolina State College; U.M., University of Michigan. The 1954 collections from the Hudson River were made by Warren F . Rathjen and Lewis C. Miller (RM) of the New York State Conservation Department. The mileage from the mouth of a river is sometimes given. Thus PX40 denotes a distance of 40 miles from the mouth of the Patuxent PUver . Mileage in the Pamunkey and Mattaponi Rivers is from the mouth of the York River. In the case of the Chickahominy River, its mileage is measured from the mouth of the James River . Standard geographical abbreviations are used. For each collection the following data are given: Loca- tion, date of collection, number of specimens counted, in parenthesis, and catalog number. Quebec: St. Lawrence R. at Chateau- Richer Village about 20 mi . west of Quebec City, Oct. 22, 1944, (62), C.U. 29605. New Brunswick, Miramichi R.: Vicinity of Chatham, Dec. 7-21, 1952, (50), C.U. 22135; Dec. 1953, (28), C.U. 28376; Loggieville to Newcastle, Nov. 15-Dec. 15, 1955, (55), C.U. 29727. Nova Scotia, Philip R . : 5 miles above Moater, Nov. 1955, (7), not catalogued; Ph5, Dec. 1955, (60), not catalogued. Rhode Island: Pt. Saconnet, May 11, 1953. (37), C.U. 20641; Newport, May 24, 1955, (21), C.U. 29091. Connecticut, Cos Cob Power Plant: Jan . 1953, (6), C.U. 21709; Jan. -Feb. 1953,, (22), C.U. 20640; Oct. 1953, (21), C.U. 28377; Dar- ien, L.I. Sd., Oct. 30, 1954, (1), C.U. 28341; Greenwich, L.I. Sd., Nov. 11, 1954, (1), C.U. 28342; Darien, L.I. Sd., Oct. 30, 1954, (1), C.U. 28343; Greenwich, L.I. Sd., Oct. 19, 1954, (5), C.U. 28344; Fairfield, L.I. Sd., Aug.- Nov. 1954, (14), C.U. 28267. New York, Hudson River: 1936: Haverstraw, Aug. 25, (27), C.U. 5180; Nyack, Sept. 1, (10), C.U. 27063. 1949: Port Ewen, Aug. 26, (12), C.U. 18215; Haverstraw and Stoney Pt., Aug. 5, (36), C.U. 15463; Haverstraw and Stoney Pt., Sept. 13, (13), C.U. 18219; Stoney Pt., Aug. 26, (21), C.U. 18221. 1950: Catskill to Piermont, Sept. 4-9, (36), C.U. 21070. 1952: Kingston, Oct. 9, (2), C.U. 22714; Fishkill, Aug. 21, (3), C.U. 22715; Fishkill, Oct. 9, (2), C.U. 22716; Haverstraw, Aug. 7, (2), C.U. 22717; Haverstraw, Aug. 15, (7), C.U. 22718; Haverstraw. Oct. 9, (3), C.U. 22719. 1953: Coxsackie, Sept. 10, (50), C.U. 24028; Beacon, Sept. 11, (12), C.U. 24037; Haverstraw, Sept. 11, (55), C.U. 24043. 1954: Coxsackie, Aug. 4, (50), C.U. 27128; Coxsackie, July 26, (23), RM 116; Cox- sackie, Oct. 14, (9),. RM 190; Coxsackie, June 23. (54), C.U. 26281; Coxsacki, July 13, (16), C.U. 26380; Middle Ground Is., July 8, (8), RM 89A; Haverstraw, Sept. 30, (34), RM 184; Haverstraw, Aug. 9, (9). RM 151; Haverstraw, Aug. 13,(6), RM 143; Haverstraw, July 29, (40). RM 126; Haverstraw. Sept. 21, (23), RM 175; Haverstraw, Oct. 20, (30), RM 192; Haverstraw, July- Aug. (12), RM 1-12; Harmon, Aug. 27, (20), RM 155; Harmon, Sept. 21, (27), RM 174; Croton, Nov. 4, (19), RM 194; Nyack, Aug. 19, (31), RM 152; Nyack, Aug. 4, (50), C.U. 27037; Palisade State Park, Sept. 10, (14), RM 168; Palisade State Park, Sept. 30, (34), RM 185; Palisade State Park, Oct. 20, (20). RM 193. New Jersey: Mullica R., at Lower Bank, Feb. 16, 1954, (45), C.U. 25779; Delaware R. at Deepwater: Oct. 9, 1952(83), C.U. 22004 and Aug. 26, 1953, (39), C.U. 23755; Maurice R., Yaup Shore Station, Sept. 8, 1954, (16), C.U. 28453. Chesapeake Bay and tributary rivers: Susquehanna R. at B. and O. R.R. Bridge: Sept. 14, 1955, (14), C.U. 29724; Sept. 27, 1955. (46), C.U. 29675. ElkR.: Aug. 4, 1955, (49), C.U. 29098. Sassafras R.: Buoy #6, Sept. 15, 1955, (15), C.U. 29718; Ordinary Pt., Sept. 15, 1955, (48), C.U. 29690. Middle. R.: Piney Pt. Bar, Sept. 28, 1955, (15), C.U. 29697. BackR.: Back R. Bridge, Sept. 28, 1955, (19), C.U. 29674; Witchcoat Rt . , Sept. 28, 1955, (22), C.U. 29677. Patapsco R. System: Curtis Cr., Sept. 26, 1955, (4), C.U. 29722; Stoney Cr., Sept. 22, 1955, (8), C.U. 29686; Stoney Cr., Sept. 22, 1955, (2), C.U. 29701; Curtis Cr., Sept. 26, 1955, (1), C.U. 29684; Marley Cr., Sept. 26, (3), C.U. 29688; Curtis Bay, SleddsPt., Sept. 26, 1955, (2), C.U^ 29700; Stoney Cr., Sept. 22, (29), C.U. 29717. Chester R., 1955: 2-1/2 miles below Chestertown, Aug. 4, (34), C.U. 28812; Hail Pt., Sept. 6, (16), C.U. 29709; Near Bay #35, Sept. 16, (2), C.U. 29693; Wilner Pt., Sept. 16, (1), C.U. 29720; Below Chestertown Yacht Club, Sept . 16, (2), C.U. 29706; Piney Pt., Sept. 16, (3), C.U. 29708; Milton Pt., Sept. 16, (8), C.U. 29719. Severn River System, 1955: Old Hatch- ery, July 17, (5), C.U. 29771; LongPt., July 28, (1), C.U. 29793; Epping Forest, July 28 (3), C.U. 29776; Mathews Pt., July 27, (6), C.U. 29784; Little Round Bay Cr., July 28, (1), C.U. 29765; Springer., July 20, (4), C.U. 29779; 1 mi. above Old Hatchery, July 27, (3), C.U. 29764; Saltwater Cr., July 28, (1), C. U. 29780; Valentine Cr., July 27, (4), C.U. 29774; Severn - side, July 29, (1), C.U. 29790; Sherwood Forest, July 29, (2), C.U. 29777; Rt. 301 bridge, Aug. 9, (1), C.U. 29767; PooseyCr., July 29, (1), C.U. 29766; Rock Cove, July 27, (2), C.U. 29768, Miles R., 1955: Miles R. Bridge, Aug. 25, (3), C.U. 29685; Mouth Royal Oak Cr., Aug. 25, (3), C.U. 29682; Yacht Club, Aug. 25, (5), C.U. 29704; Miles R. Bridge, Aug. 26,(7), C.U. 29672; Miles R. Bridge, Aug. 26, (7), C.U. 29687; Miles R. Bridge, Aug. 26, (13), C.U. 29696. Choptank R . : 1 mi . below Ganey Wharf, Aug. 3, 1955, (44), C.U. 28756. Patuxent R. System: Prince Frederick, Aug. 27, 1953, (36), C.U. 23507; 1955: St. Leon- ard Cr.. Aug. 5, (3), C.U. 29769; PX40, July22, (1), C.U. 29770; Below first bend, July 13, (2), C.U. 29773; PX21, Sept. 16, (2), C.U. 29772; Battle Cr. at Resthaven, Aug. 10, (1), C.U. 29783; Kaylor's Landing, Sept. 15, (1), C. U. 29792; Battle Cr., Aug. 10, (8), C.U. 29778; PX21, June 17, (1), C.U. 29788; PX22. June 17, (1), C.U. 29786; Mill Cr., Aug. 4, (1), C.U. 29775; Nottinghan, Sept. 15, (1), C.U. 29791; PX40, July 13, (1), C.U. 29787; Holland Pt.. Sept. 16, (1), C.U. 29789; Holland Beach, Aug. 8, (3), C.U. 29785; PX40, July 22, (12), C.U. 29781; PX34, July 26, (17), C.U. 29782. NanticokeR., 1955: Sandy Hill Beach, Aug. 2, (16), C.U. 28712; Lewis Wharf, Aug. 2, (11), C.U. 28724; Sharptown, Aug. 3, (50), C.U. 28751. Wicomico R., 1955: Greenhill Church, Aug. 2, (50), C.U. 29096. Potomac R. System: Fort Belvoir, Oct. 13, 1948, (18), C.U. 28996; Toll Bridge on Rt. 301, Oct. 30, 1953, (12), C.U. 25568; 1955: Liverpool Pt., Oct. 18, (13), C.U. 29687; Quan- tico, Oct. 18, (22), C.U. 29723; Wicomico R. Oct. 18, (29), C.U. 29680; Wicomico R. at Rock Pt., Oct. 18, (27), C.U. 29676; Morgan Haven, Oct. 18, (31), C.U. 29679; St. Georges Cr., Oct. 19, (33), C.U. 29673; Fanwick, Oct. 19, (12), C.U. 29681. Crisfield, Md.: Aug. 10-11, 1948, (7), U. Md. 2128; Aug. 10-11, 1949, (39), U. Md. 3055; July 12-14, 1949, (11), U. Md. 2934; Sept. 12, 1949, (1), U. Md. 3108; July 26, 1949, (11), U. Md. 2961; 1951: Oct. 5, (1), U. Md. 3931; Aug. 8 (6), U. Md. 3755; Aug. 30, (2), U. Md. 3794; Aug. 29, (3), U. Md. 3703; July 11, (11), U. Md. 3609; July 10, (9), U. Md. 3588; July 10, (2), U. Md. 3377; July 9, 1952, (23), U. Md. 3658. Rappahannock R. System, Va.: Betw. Tappahannock and Fredricksburg, Aug. 23-25, 1951, (10), not catalogued; Saunders Wharf, Aug. 30, 1953, (50), C.U. 23672; R38, Mar.- April 1954, (23), C.U. 26149; July 22, 1954, (12), C.U. 28056; Tappahannock, Aug. 29, 1954, (26), C.U. 28317; Layton's Landing, July 18, 1955, (50), C.U. 28894. York River System, Va.: York R . : Almondsville to West Point, Mar. -April 1954, (79), C.U. 26150; Pages Rock YIO, Mar. -April 1954, (7). C.U. 26151; West Point, July 1955, (52), C.U. 29089. PamunkeyR.: Mussel Pond Beach, Aug. 4, 1949, (11), C.U. 14666; Sweet Hall Landing, Aug. 11, 1949, (8), C.U. 14466; Hill Reach, Aug. 21, 1949, (1), C.U. 14383; Sweet Hall Landing Pocket, Aug. 11, 1949, (1), C.U. 14455; Sweet Hall Landing, Aug. 31, 1949, (7), C.U. 14579; Hillis Reach, Sept. 29, 1949, (6), C.U. 14601; Hillis Reach, Station #12, July 28, 1949, (13), C.U. 14856; P40 to P65, Aug. 4-29, 1953, (16), C.U. 23581; West Point to Lestor Manor, Aug. 12-22, 1952, (35), C.U. 21941; P48, July 21, 1954, (50), C.U. 26561; P43, July 19, 1955, (50), C.U. 28613. Mattaponi R . : West Point to Aylett, Aug. 25-28, 1952, (15), not catalogued; M45 to M55, Summer 1955, (l^C.U. 23933. James River System, Va.: James R . : Jamestown Island to Hopewell, Sept. 3-10, 1952, (9), not catalogued; Sandy Pt . , Aug. 30, 1953, (4), C.U. 23468; Hopewell, Mar.- April 1954, (58), C.U. 26147; J42, July 21, 1955, (7), C.U. 28743; J35, July 21, 1955, (58), C.U. 28646; Hopewell, July- Aug. 1955, (44), C.U. 29090. Chickahominy R.: Richmonds Farm, June 26, 1949, (18), C.U. 16747; C55, July 23, 1954, (41), C.U. 26642; C43, July 21, 1955, (27), C.U. 28639. Norfolk, Va.: April 13, 1953, (15), C.U. 20627. Albemarle Sound, N.C.: 1 mi eastRt. 37 crossing, April 15, 1953, (26), C.U. 20626; N. endRt. 32 bridge, Aug. 28-29, 1953, (34), C.U. 23541; Mouth North River, Mar. 29, 1954, (17), C. U. 25842; North side bridge, Aug. 30, 1954, (16), C.U. 28322; The following N.C.S.C . collections have no catalog numbers: Albemarle Sd., July-Sept., 1946, (23); Albemarle Bridge southside, July 26, 1946, (9); Albemarle Sd., northside, Sept. 28, 1945, (3); Albemarle Sd., July 1945, (2); Albemarle Sd., 1955, (41); Little R., Summer 1954, (27), C.U. 28337; Roanoke R., April 1954, (5), C.U. 28336; Chowan R., Aug. 30, 1954, (44), C.U. 28161. Pamlico R., N.C.: Washington Bridge to 5 mi. downstream, Oct. 27, 1954, (25), C.U. 28455. Cape Fear, N.C.: Collections of N.C .S .C. with no catalog numbers; 1951, (7); Cape Fear River, Aug. 2, 1952, (2); 1953, (17); 1954(2). Santee -Cooper River System, S.C.: Lake Moultrie, Oct. 28, 1952, (2), C.U. 22073; Pinopolis Dam, April 2 -May 5, 1954, (49), C.U. 26148; Lake Marion, Sept. 10, 1954, (50), C.U. 28225; Pinopolis Dam, Mar. 31, 1955, (9), C.U. 28520; Below Lake Moultrie Dam, Mar. 31, 1954, (6), C.U. 25993; Tailrace Canal, Mar. 31, 1955, (4), C.U. 28518; Pinopolis Dam, Mar. 29, 1955, (10), C.U. 28511; Tailrace Canal, April 20, 1955, (7), C.U. 28519; Diversion Canal, June 30, 1955, (55), C.U. 29017; Tailrace Canal, Sept. 1, 1955, (16), C.U. 29088; PinopoUs Dam, Sept. 1955, (14), C.U. 29670; Pinopolis Dam, Nov. 7, 1955, (19), C.U. 29671. Ashley River, S . C . : Runney Meade Plantation, Nov. 22, 1953, (3), C.U. 24984. Broad R., S.C: Columbia, April 9, 1955, (17), C. U. 28521. Gulf of Mexico: West Florida, (4), U.S. N.M. 35144, 126060, 126061, and 21312; Alabama R., mouth of Autauga Cr., June 1955, (2), C.U, 29628; Alabama, June 1955 (4), Ala. Poly. Inst. California: Sacramento R., 7 mi. n. Antioch Bridge, Aug. -Sept. 1945, (50), C.U. 28573; Sacramento R., near Three Mile Slough Bridge, Aug. -Sept. 1945, (73), C.U. 28574; Sacramento R. at Rio Vista, Aug. -Sept. 1945, (62), C.U. 28575; Delta Area, San Francisco, 1951, (43), C.U. 20724; Carquinez Straits, Aug. 18, 1943, (20), U.M. 142369; Carquinez Straits, Sept. 11, 1946, (16), C.U. 28576. METHODS The specimens that were examined ranged from 26 to 489 mm . in standard length; the majority were either 0 (young) or I (yearling) in age. In order to count the number of gill rakers present on tiie first left branchial arch, it was necessary to remove the arch from the fish. Gill rakers were counted using a binocu- lar microscope; they were tabulated as follows: the number present on the upper arm plus one at the angle of the arch plus the number on the lower arm . All developed gill rakers were counted. At the extreme ends of the arch, tubercles sometimes occurred. If higher than the diameter of tlieir base they were counted; if not, they were considered as rudiments and not counted. Some of the specimens had been put in a deep freeze and later were transferred to formalin. In these cases mucus had built up on the gill arches and it was necessary to scrape it off before counts could be made. TTie same situation existed when specimens had been poor- ly preserved. Gill raker counts were not made on fish below 26 mm . due to the difficulty of re- moving the entire gill arch. Comparisons between samples were made by the following statistical procedures: analysis of variance, analysis of covariance, t - test and chi- square test and were in accord- ance with the methods followed by Snedecor (1946) and Steel and Torrie (ms.). Chi -square tests were run on samples that had a binomial distribution and on distributions that approached normality but the resulting level of significance was the same as when an analysis of variance was used. Statistical significance is designated in the tables as follows: N.S. - not significant; * - significant at the five percent level; ** - significant at the one percent level . If the age of specimens in the sample is not stated in the table title, it is designated after the individual sample as: yg. - young or yr. - yearling. Owing to environmental variation Rounse- fell and Everhart (1953) considered it advisable to use the same year class in comparing samples of fish. In this study of gill-raKer counts of striped bass, the same year classes are not always available from all the areas studied. Therefore, when several year classes from one river or area were compared and the differences found to be non- significant, these samples were combined and used to make comparisons with other areas. When the term "by observation" is used it indicates that a previous t - test with less divergence between the means had been made and the results were significant. In this paper a population is considered in the same sense as Mayr, Lindsley and Usinger (1953:308) use the term local population, that is, "the individuals of a given locality which poten- tially form a single interbreeding community." The term subpopulation is used to denote the specimens from the James, York -Rappahannock and Upper Bay Rivers in the Chesapeake Bay fol- lowing the findings of Raney (ms.). RESULTS Variation in the number of gill rakers with age.- -In order to determine if the number of gill rakers changes with age, a study was made of counts from localities where young of the year and older fish were available. The results are based on fish classified as O, I and a few II. The best way to determine if there is a change with size or age is by use of statistical regression. A plot of the data was made on a graph and from this it was ascertained that the regression was linear. Therefore using the formula Y = y"+ b (X-Jc), a linear regression line was calculated (Snedecor, 1946). To get a clear picture of any possible change in gill raKer number, fish from one year class and one locality were selected. One of the underlying assumptions of a regression, which is a moving average, is that the variances of the individual samples be homogeneous. This was verified by Bartlett's test of homogeneity of variance . The results of several samples and com- binations of samples are shown in table 1 . First a regression on the individual samples was run. In all the rivers or river systems (Rappahannock, York, James, Albemarle Sound, and Santee- Cooper) the slope of the regression line fell very close to the abscissa. This was true whether the samples were just 0, I, II or any combination of these. The same held true if the counts were from the total number of gill rakers on the first left branchial arch or just the num- ber of gill rakers from the upper arm of the same branchial arch. From observation of table 1 it seems that the (plus) or (minus) slopes are just random variations and if a large num- ber of samples were taken the total population would have a slope of zero. The above results indicate that there is no change in the number of gill rakers from O to I. We do not have adequate collections of III and older age groups to determine if the number of gill rakers change with these ages . Variation in number of gill rakers with sex. --A study was made of striped bass, that were collected from the Delaware River in 1952, to determine if the number of gill rakers varied with sex. Specimens were immature and ranged in standard length from 72 to 198 mm . As there is no known way of determining the sex from external characters, a dissection was made . A section of the gonad was removed and a smear was examined using a compound micro- scope. At- test was used to compare the num- ber of gill rakers in the sexes (table 2) and proved not to be significantly different. There- fore, it is concluded thai there is no sexual difference as far as gill rakers are concerned. Populations. The Chesapeake Bay. --The 1955 year class and the 0 age group are available from the majority of the river systems in the Chesapeake Bay region. An analysis of variance was run on this group using the total number of gill rakers (table 3) and the F - value was highly significant. This same high significance also occurred when the number of gill rakers on the upper arm of the first branchial arch was used as the test criterion (table 4). For these data, the analysis of variance shows that more than one population exists in the Chesapeake Bay. In order to determine where similarities and differences occurred, meaningful comparisons were carried out based on geographical locations. Therefore, an analysis of variance using the total number of gill rakers was performed on samples from the Chesapeake area, excluding those from the Rappahannock, York and James River Systems. The resulting F - value was significant at the one percent level but with a much lower magnitude than when these river systems were included (table 5A). As the mean of the Patuxent River sample was the lowest value of any in the Upper Bay area it was deleted in the next test. The resulting F - value proved to be significant at the 5 percent level (table 5B). Still another analysis of vari- ance was carried out with the Wicomico River sample dropped from the above grouping. The mean of the latter was the highest except for that of the Choptank, but due to its more southern location on the eastern shore it was more mean- ingful to omit it. The F - value from this test was not significant (table 5C). A similar series of analyses of variances was worked out using the number of gill rakers on the upper arm of the gill arch . The F - value was highly significant when the whole bay area was included (table 4). When samples from the Rappahannock, York and James were excluded the resulting F was highly significant, but the magnitude was less (table 6A). Omitting the Patuxent sample from the Upper Chesapeake Bay area, F became non- significant (table 68). T - tests were executed for the 1955 year class and 0 age based en total numbers of gill rakers with the following results: A test between the Rappahannock and York River System samples was not significant (table 7A) . However, when those of the York and Rappahannock Systems were tested against the James River sample, there was significance at the one percent level (table 7B) . Also there was found to be no significant differ- ence between upstream and downstream samples from the James River (table 7C). When the samples from the west shore of Chesapeake Bay (excluding Rappahannock, York, and James) were lumped and compared with the combined east shore samples, the result was just significant at the 5 percent level (table 8A) . A similar com- parison using the number of gill rakers on the upper arm of the arch showed no significant difference (table 8B) . For the 1954 year class, no significant differences in total numbers of gill rakers were found between upstream and downstream samples from the York and James River Systems. This involved a comparison between 0 and I in both cases (tables 9A and 9B). When total gill raker counts of 0 and I samples of the Rappahannock 1953 year class were compared, t was found to be significant at the 5 percent level (table lOA) . However, using the counts of the upper arm there was no sig- nificance (table lOB) . A t-test was also run on the samples of the 1953 year class from the York River System. Using the count on the upper arm there was no significant difference between the Mattaponi 0 and the York I (table IOC), but when using the total number of gill rakers, the difference proved to be significant at the one percent level (table 11 A). When a covariance was run to ad- just the fish to a common standard length the F - value was not significant (table 12). A comparison of Rappahannock and York samples was made by use of a t - test for the above data. For the total number of gill rakers of the I specimens there was no significant difference (table 11 B). By observation, the mean of the Rappahannock (24.68) versus the mean of the York (24.69) was not considered to be significantly different for the 0 age group either. An analysis of variance of 0, I and II age groups of the 1952 year class in the York River System proved not significant (table 13) . Also an analysis of variance was carried out for the 0 age group of the 1949 year class from Crisfield, Maryland and there was no signifi- cance (table 14). Samples of 5 year classes (1949, 1952, 1953, 1954 and 1955) from the James River were compared by an analysis of variance. It was found that there was a signifi- cant difference (table 15). The mean value of the gill raker count on the first branchial arch and those from the upper arm of the same arch of samples of young of the 1955 year class from 17 rivers were ranked from the lowest to the highest under the two categories. The resulting correlation co- efficient (r = .806) indicates a good correlation. In summarizing the results given above, a biological difference was considered to exist only if the statistical differences were of a large magnitude when using both the count on the upper arm and the total number of gill rakers. The results seem to indicate that several subpopula- tions of striped bass exist in the Chesapeake Bay. The first subpopulation is in the Upper Bay; this includes the rivers north of the Rappahannock on the west shore and all the east shore rivers covered in this study . The Patuxent River sample has a lower gill raker count than the other rivers in the Upper Bay but perhaps this is not of bio- logical significance and may be due to random variation or other sampling procedures. How- ever, until stronger evidence is presented that the Patuxent River is biologically different, it should be considered as belonging to the homo- geneous subpopulation from the Upper Chesapeake Bay. The Rappahannock and York striped bas^, belong to another subpopulation, while the Jameb is the third subpopulation. There doesn't seem to be any upstream - downstream difference in any of the rivers that can be deemed biologic illy significant . Enough statistical difference exists among year classes from the same locality so that it seems unwise to lump year classes in making comparisons between localities. Study of addi- tional year classes from throughout the Chesa- peake Bay region may modify these conclusions . Comparison of populations above and below Pinopolis Dam, South Carolina. --A uniq ;e situation exists in the Santee-Cooper Reservoir System of South Carolina . With the completion of Pinopolis Dam in 1942, water was impounded in Lake Moultrie and Lake Marion. This pro- vided a fairly effective separation for striped bass above and below the dam . Scruggs and Fuller (1955) found that there is slight recruit- ment of fish from the Cooper River to the reser- voir population during the operation of the locks; they also found that adequate spawning occurred above and below the dam . Specimens of age group 0 were obtained above the dam, while I, and II were found below. An analysis of variance, using the 1953, 1954 and 1955 year classes and the three age groups, was run to determine if these specimens could be considered to be from the same population. The resulting F - value based on the total num - ber of gill rakers was highly significant and is probably due to the variation among year classes and age groups (table 16). The best way to compare fish having dif- ferent standard lengths is by use of the analysis of covariance (Marr 1955). In order to use this test the regression slopes cf the samples must belong to the same population . The F - value, for the "homogeneity of within sample regres- sion" based on the total number of gill rakers was just significant at the 5 percent level (table 17). A test of adjusted sample means made us- ing the total number of gill rakers (table 18) gave an F value which was just significant at the 5 percent level. When dealing with wild populations, it is difficult to know just where to draw the line for significance due to factors that may cause the data to be non -random . Similar covariance tests were also run, using the number of gill rakers on the upper arm of the first branchial arch. The test determin- ing the homogeneity of the slopes proved to be barely significant (table 19), while the test of adjusted sample means was not significant (table 20) . As the above values were not highly significant, indications from the gill raker data are that the Santee-Cooper River System speci- mens belong to one population. The Hudson River population. - -The most numerous Hudson River collections available are from the 1954 year class and the 0 age group. Specimens are available from Palisades State Park to Coxsackie, New York. When an analysis of variance using the total number of gill rakers was run on these samples, the resulting F value proved to be highly significant (table 21). A similar test, based on the number of gill rakers on the upper arm, was also highly sig- nificant but with a lower magnitude (table 22). Based on a purely statistical outlook, the results of these tests indicate that some hetero- geneity of samples exists in the Hudson River. However, looking at it from a biological point of view, the magnitude of these differences doesn't seem to indicate more than one population. A chi- square test was performed on the same data from the total number of gill rakers. The total chi-square value was 42.75, which was signifi- cant at the 5 percent level. Bartlett's test for homogeneity of variances was also worked out for the above samples . The resulting value of chi-square (1.01 with 5 degrees of freedom) was not significant. By deleting the Coxsackie sample from the hudson samples and running a chi-square test (X^ = 28.08, with 20 degrees of freedom), the results indicated that these (lower river) samples were homogeneous A test was run to compare the samples from Haverstraw to Palisades State Park with Coxsackie, New York; t proved to be just above the 5 percent level of significance (table 23) . This difference was not enough to consider the divergence between upstream and downstream tx) be biologically significant. A test using the total number of gill rakers was run for samples of the 1953 year class from Coxsackie and Haverstraw and t was not sig- nificant (table 24). An analysis of variance was worked out for the 1949 year class with samples from Port Ewen, Stoney Point and Haverstraw; the F -value was not significant. The same was true when a sample from Port Ewen was com- pared with those from Stoney Point to Haverstraw (table 25) . An analysis of variance was conducted among six year classes (1936, 1949, 1950, 1952, 1953, 1954) from the Hudson River and was not significant (table 26) . A correlation coefficient was determined between the upper arm and the total number of gill rakers on the first arch for the samples from 1954 year class from Hudson River. The result- ing value (r = .885) indicates a good correlation. In summary, even though some significant differences were found between samples within the Hudson River, biologically it should be con- sidered as one population. There is an overall homogeneity among the several year classes studied from the Hudson River. The samples from the Hudson River had the hi^est gill raker counts of any populations along the Atlantic Coast (tables 42 and 43) . A comparison of the James and Hudson populations. --Raney (ms.) found that within the Chesapeake Bay the James River subpopula- tion is the best defined; ihc other two are the York -Rappahannock and the Upper Bay. There- fore it is meaningful to make a comparison of the number of gill rakers of samples from the James and Hudson Rivers. A highly significant t-value was indicated by a t - test of the 1954 year class (table 27A) and the 1953 year class table 27B). Gill raker counts from the James River are high and approach those from the Hudson River closer than do other samples of striped bass from the Chesapeake Bay. Due to the high magnitude of the t - values, indications seem to point to the fact that the Hudson and James River samples belong to separate populations. The Long Island Sound population. -- Raney, Woolcott and Mehring (1954:394) have shown that there are movements of striped bass between the western end of Long Island Sound and the Hudson River. Merriman (1941:38-49) found that migratory schools of the Chesapeake Bay population cross the eastern end of Long Island Sound during the fall and spring. There- fore it was of interest to note how the samples from the western quarter of Long Island Sound compare to those of the Chesapeake Bay and Hud- son River populations. Collections from the western end of Long Island Sound were divided into year classes (1949, 1950, 1951, 1952 and 1953) and an analy- sis of variance was run. The result was not significant (table 28), so that it is valid statis- tically to lump these year classes together as a composite sample to get a general mean based on the total number of gill rakers. In the Hud- son River, homogeneity of gill raker numbers exists among the 6 year classes studied as demonstrated above . Therefore, in order to make the comparison among fish from the 3 areas, the mean of the 1954 year class from the Hudson was compared with the general mean of 5 year classes from the western end of Long Island Sound and the mean of the 1955 year class from all the tributaries that were sampled from the Chesapeake Bay. Striped bass from the western end of Long Island Sound were found to be intermediate between the Chesapeake Bay and Hudson River populations (table 29). Similar comparisons were made for other year classes that had smaller samples and in all cases the relationship was the same as that stated above. A comparison of populations from California with those from the Chesapeake Bay and Hudson River . --In order to make compar- isons with other localities it was necessary to find samples from several year classes from the Chesapeake Bay that were homogeneous. For the total number of gill rakers, samples from the Upper Chesapeake Bay were tested using an analysis of variance and the F - value was just significant at the 5 percent level (table 30) . A similar test using the number of gill rakers on the upper arm gave an F - value which was not significant (table 31). It is concluded that the samples from the Upper Bay are biologically homogeneous and therefore can be used to make comparisons with other areas. Additional analyses of variance were run between samples from several year classes of the James River and samples from the York -Rappahannock Rivers. In all cases the F - values were highly significant indicating that they were not homogeneous among year classes . An analysis of variance based on the total number of gill rakers was conducted for the samples from California, which included the 1943, 1945 and 1951 year classes and F was significant at the one percent level (table 32). A chi- square test was run on the same samples using the numi- ber of gill rakers on the upper arm and was significant at the one percent level (table 33) . IDue to the heterogeneity existing among year classes in California, an analysis of variance was carried out for samples of the 1945 year class; the F was not significant in this case (table 34). At- test using the total number of gill rakers was worked out between the Upper Chesa- peake Bay composite sample and a sample from the California 1945 year class; t was highly sig- nificant and had a considerable magnitude (table 35A). The 1945 year class from California was used because of the larger number of specimens available. The 1945 year class from California was also compared with the composite sample of year classes from the Hudson River; t was significant at the 5 percent level (table 35B). Results from the above tests of gill raker counts point to a wide difference between the Upper Chesapeake Bay and California pop- ulation at the present time . The latter is much more closely related to the Hudson River popula- tion on the basis of this character. A comparison within populations from Canada, Delaware River and Albemarle Sound. -- Samples are available from the St. Lawrence River, the Miramichi River in New Brunswick and the Philip River in Nova Scotia. A com- parison of the samples collected from the Miramichi River in 1952, 1953, and 1955, was made using chi- square as the test criterion; the result based on the total number of gill rak- ers was significant at the 5 percent level (table 36A) . However, no significant difference was found when the same test was run based on the number of gill rakers on the upper arm (table 36B). This indicates that there was little differ- ence among these year classes . Samples collected in 1955 from the Miramichi and Philip Rivers were compared by at- test; the result using the total number of gill rakers was not significant (table 37A). A t - test using the number of gill rakers on the upper arm was run comparing the collections of 1952, 1953 and 1955 of the Miramichi with the 1944 collection from the St. Lawrence River; t was highly significant (table 37B). At- test based on the total number of gill rakers was run comparing samples of the three year classes from the Miramichi River with those from the Philip River; t was not significant (table 37C). The results indicate that there is a difference between the St. Lawrence River and the other two rivers, the Philip and the Miramichi . An analysis of variance using the total number of gill rakers was conducted for three different year classes of specimens collected from the Delaware River; the resulting F - value was not significant (table 38) and indicates that the samples studied are homogeneous. In the Albemarle Sound, gill raker counts were made on several year classes and age groups. An analysis of variance using the total number of gill rakers was run on these samples and F proved to be highly significant (table 39) . A chi -square test was run on the same data based on the number of gill rakers on the upper arm; it also was significant at the one percent level (table 40). Samples from the 1953 year class were compared by an analysis ofvariance; the F was highly significant (table 41). The results indicate that in the Albemarle Sound differences exist among and within yeaj clarses. An overall comparison of several populations. - - In order to get an overall picture of the populations based on gill raker counts, the means of the total number of gill rakers on the first left branchial arch are shown in table 42. The locations are given from north to south along the Atlantic Coast. A similar table was made for the number of gill rakers on the upper arm of the first left branchial arch (table 43) . The means shown in these tables include differ- ent year classes and age groups and present a graphical comparison of the areas studied. A series of t - tests based on the total number of gill rakers (unless otherwise indicated) were carried out from observations of tables 42 and 43 . The following comparisons were made in order to determine the relationship of samples from different localities along the Atlantic Coast . A sample from the Miramichi River in New Brunswick was compared with the Santee- Cooper River System sample for the 1953 year class; no significance resulted (table 44A) . A test be^ tween the Miramichi River sample versus the Upper Chesapeake Bay subpopulation for the 1955 year class was highly significant (table 44B) . By observation, there is a significant difference be- tween the samples from the James and Miramichi Rivers for the 1955 year class. The result of a t - test between the York -Rappahannock sub- population and the Miramichi River sample for the 1955 year class was not significant (table 44C). A comparison between the York -Rappahannock subpopulation versus the Santee-Cooper River System sample for the 1955 year class was sig- nificant at the 5 percent level (table 45 A). How- ever, a similar test based on the number of gill rakers on the upper arm was not significant (table 45B) . Table 45C shows that heterogeneity exists between the Chesapeake Upper Bay sub- population and the Santee-Cooper River System 10 sample for the 1955 year class. Also by ob- servation, there is a significant difference between the James River and Santee-Cooper River System samples for the 1955 year class. In order to determine the relationship between the Chesapeake Bay and the Albemarle Sound, a comparison was made between the York -Rappahannock sample and the Albemarle Sound sample for the 1955 year class. It was just above the line for the one percent level of significance (table 46A) .At- test of the samples of the 1955 year class from the James River and Albemarle Sound was highly signifi- cant (table 46B). A similar test using the num- ber of gill rakers on the upper arm was significant at the one percent level, but at a lower magnitude (table 46C) . However, in com- paring the Upper Chesapeake Bay subpopulation with the Albemarle Sound sample for the 1955 year class, there was no significance (table 47A). In a comparison between Albemarle Sound sample and the Santee-Cooper River System sample for the 1955 year class, t was signifi- cant at the one percent level (table 47B). Indications of the relation of the Delaware River population to that of the Chesapeake Bay were determined by comparing three homogene- ous year classes from the Delaware River with the York -Rappahannock sample of 1955; t in this case was significant at the one percent level (table 48A). The same level of signifi- cance resulted also when the Upper Chesapeake Bay subpopulation for the 1955 year class was compared with the homogeneous sample from the Delaware River (table 48B). However, when the James River sample of the 1955 year class was compared with that of the Delaware River sample there was no significance (table 48C). A homogeneous sample of six year classes from the Hudson River, when compared with a homogeneous sample from the Delaware River was highly significant (table 49) . A few specimens were available from the Gulf of Mexico. Table 42 shows that the means of the total number of gill rakers of striped bass from the Gulf of Mexico fall in the same range as those from the Santee-Cooper River System, South Carolina . When the same fish are considered on the basis of the number of gill rakers on the upper arm, the means then fall in line with the Chesapeake population (table 43) . DISCUSSION Important sources of the striped bass are Albemarle Sound, Chesapeake Bay, Delaware River and Hudson River. Merriman (1941:42) considered the Middle Atlantic area from Cape Hatteras to Cape Cod as the center of abundance for striped bass and tagging experiments in- dicated that there was comparatively little encroachment by this stock on the populations to the north and the south. Merriman (1941:36- 38) tagged 2,573 fish at Montauk,Long Island and in the Niantic and Thames Rivers, Connecticut, between April 1936 and June 1938. Returns from fish tagged in this region reached 544 by July 1938 and gave abundant proof of a coastwise northern migration in the spring, a relatively stable popula- tion showing no movement of any consequence in the summer and a southern migration in the fall and early winter. Scattered returns, based on the above tagging experiment, from New Jersey, Delaware, the entrance to Chesapeake Bay and North Carolina show that striped bass may travel great distances in their southern migration. Vladykov and Wallace (1952:174-175) showed by tagging experiments in the Chesapeake Bay and Albemarle Sound, North Carolina that there was little exchange between the two areas. However, it is clear that some striped bass migrate out of the mid Chesapeake Bay area . Vladykov and Wallace (1952:174) tagged 1,869 fish during 1936^ and 1937 in the middle Chesapeake Bay, and 28 (1.5 percent) were later captured along the Atlantic coast; of the 662 bass marked in the Potomac River, only two (0.3 percent) were taken outside the Bay. The James Rivjfer popula- tion did not contribute to the stragglers along the Atlantic Coast north of the Chesapeake area. Raney, Woolcott and Mehring (1954:395) show that a sample of striped bass taken at Point Saconnet, Rhode Island was probably of Chesa- peake or Delaware rather than Hudson stock. This is in agreement with the results from the above-cited tagging experiments which demon- strated a northward movement from the Chesapeake Bay. Evidence of movement within the Chesa- peake Bay was presented by Pearson (1938:843-845) 11 in a tagging experiment conducted off Annapolis, Maryland in July and August 1931 . Out of a total of 305 fish tagged, 9 were recaptured south of the point of release in the Bay and 80 were recovered north of the point of release. Pear- son concluded that there was little movement from the Upper to the Lower Bay. Vladykov and Wallace (1952:165-172) found that specimens tagged in the middle Chesapeake Bay during the summer and fall remained where they had beer released during the summer but in October moved slowly southward, mainly along the west shore of the Bay. They also found that the pop- ulations in the James and Potomac Rivers were relatively stationary. Raney (ms.) concluded on the basis of counts of spines in the first dorsal fin and the soft rays of the dorsal and anal fins that three subpopulations are present in the tributaries of the Chesapeake Bay, namely those of the James River, the York -Rappahan- nock and the Upper Bay Rivers. Gill raker counts also support this view. Using a series of statistical tests for samples from the 1955 year class based on the number of gill rakers on the upper arm and also the total number of gill rakers, the samples from the James River were separated from samples of all other rivers in the Chesapeake Bay that were studied. By the same procedure the York -Rappahannock River subpopulation was found to be significantly dif- ferent from the James cind Upper Bay River subpopulations. All the rivers on the west shore north of the Rappahannock River and all the east shore rivers that were sampled were con- sidered to belong to a homogeneous Upper Bay subpopulation as the statistical tests did not show that there were any highly significant dif- ferences among these rivers. Evidence of these three subpopulations was supported by the samples from the older year classes also. Merriman (1941:44-46) and Vladykov and Wallace (1952:172) indicated that there was in- significant movement of bass between the Chesapeake Bay and Albemarle Sound. Tables 42 and 43 give a general overall relationship be- tween the sample means and show gill raker counts to be similar for the two areas. Com- parisons, using t - tests, between the Albemarle Sound and the Chesapeake Bay populations showed that the Upper Chesapeake Bay subpopulation was more closely related to the population from Albemarle Sound than were the James and York- Rappahannock subpopulations . Raney (1954:383 and 396) indicated that the populations from the Delaware River and from the coastal rivers of New Jersey are closely related to the Chesapeake race. Gill raker counts point to the close relationship between the popula- tions from the Delaware River and the Chesapeake Bay. The next most important source of striped bass north of the Delaware River is that of the Hudson River population. Raney, Woolcott and Mehring (1954:394), reporting on the results of a tagging program, found that the Hudson River population seldom migrates eastward beyond Fairfield, Connecticut or Northport, Long Island in the western quarter of Long Island Sound; on the southside of Long Island the eastern limit was the area of Jones Beach. They concluded from fin ray counts that there is an upstream popula- tion in the Hudson River above Haverstraw and that in some years below Haverstraw there ex- isted a population derived from the Chesapeake Bay population or one that had similar characters. Raney (ms.) has modified this earlier view and considers the Hudson River samples as one pop- ulation . Evidence for this is that the first dorsal spines are relatively constant throughout a wide range in the Hudson River and tlie soft dorsal and anal rays, even though there was a significant increase in downstream samples, were con- sidered relatively small compared to differences that would indicate a racial separation . Gill raker counts also support the view that one popula- tion exists in the Hudson River. The Hudson River population has the high- est gill raker counts of any population samples in this study. Ancestors of the striped bass now found in California were collected from northern New Jersey in 1879 and 1881. Gill raker counts of recent samples from California approach those from the Hudson River and indicate a close relationship between the two. Results of gill raker counts of samples from the western end of Long Island Sound are between those from the Hudson River and Chesa- peake Bay populations . This may be due to the presence of some stock of Chesapeake origin that have intermingled with those from the Hudson River population. Raney, Woolcott and Mehring 12 (1954:385-387) reporting on a tagging program, have shown that some specimens that were tagged in the western quarter of Long Island were later recovered in the Chesapeake Bay. Tables 42 and 43 show that the means of the Canadian samples are similar to those of the Chesapeake area. Merriman (1941:41-42) thought that there were two possibilities for the presence of striped bass in Nova Scotia: first, that these fish are of northern origin and are completely separated from the populations far- ther south; and second, that they are of mixed origin from both north and south. Raney (1952: 21) speculates that striped bass migrating north- eastward from their wintering areas in the Chesapeake Bay and other more limited areas in New Jersey and New York probably travel to Canadian shores in some years. Raney (person- al communication) considers that stocks in Nova Scotia, New Brunswick and the St. Lawrence River seem to be semi -endemic but were ob- viously drawn from post Pleistocene northward migrants of the Chesapeake race. The close relationship between the Canadian samples and the Chesapeake Bay samples is upheld by the non- significant result of a t -test between the Miramichi River sample and the York -Rappa- hannock samples for the 1955 year class, the only year class from which samples are avail- able from both areas . Merriman (1941:42) considered that striped bass from the area north and south of Cape Hatteras as separate populations based on absence of returns from tagged fish . Raney and Woolcott (1954:449X working with samples of striped bass from the Santee -Cooper River System, South Carolina, found an increase in lateral line scales and a slight increase in fin ray counts in an upstream direction. They tentatively concluded that the South Carolina stock was an endemic race which in turn is dif- ferentiated into upstream and downstream forms. Scruggs and Fuller (1955) studied samples in the Santee -Cooper River System and found that op- portunity of exchange between the reservoir and Cooper River populations is restricted to the operating schedule of the navigation lock at Pinopolis Dam and that little transfer takes place; also spawning occurs above and below the dam . They found that the population in the Cooper River migrated within the river on a seasonal basis but none were found to move into salt water. No highly significant differences in gill raker counts were found in samples from above and below Pinopolis Dam . Vladykov and Wallace (1952: 148) thought that the number of gill rakers of striped bass varied inversely with length and presumably with the age of the fish and thus felt that this char- acter was not helpful in separating races. They presented a table which showed counts of gill rakers from samples from Potomac River, James River, middle Chesapeake Bay and North Carolina. Their counts of the number of gill rakers on the upper arm of the first branchial arch were com- parable with the counts made in this present paper. However, their counts for the total num- ber of gill rakers were consistantly lower by approximately one gill raker on the average . It is possible that they did not define a gill raker in the same way, especially in reference to the smaller gill rakers at the end of the lower arm . In this study almost all the specimens counted were less than 300 mm. In standard length; these showed no change with length. Vladykov and Wallace (1952) used specimens mostly larger than 300 mm . and most of the counts were made in the field. Since the point of origin was not known it seems that some differences recorded by them may be populational differences. Tables 42 and 43 show that there is little variation In the sample means from Cape Fear, North Carolina to those from the Susquehanna River in the northern Chesapeake Bay. Within this range environmental differences occur and it seems likely that if the number of gill rakers was not genetically fixed that greater variation between different localities would occur. SUMMARY AND CONCLUSIONS 1 . There is only random change in the number of gill rakers for specimens of the 0 and I age groups . 2 . The number of gill rakers does not vary between the sexes. 3 . It was not deemed that there was any biological differences in the number of gill rakers 13 counted between upstream and downstream areas in the Santee- Cooper, James, York and Hudson Rivers. Hildebrand, S.F. andW.C. Schroeder. 1928. Fishes of the Chesapeake Bay. U.S. Bull. Bur. Fish. XLIU: 1-288. 4 . Samples from above and below Lachner, Pinopolis Dam in the Santee-Cooper River Sys- 1955. tem in South Carolina belong to one population in regard to gill raker counts. E. A. Populations of Berycoid fish family Polymixiidae . Proc. of the U.S. Nat. Mus. 105 (335^ 189-206. 5. The Hudson River population is homo- geneous among year classes and indications are that there is only one population. 6 . The Chesapeake Bay population is divided into three main subpopulations . They are the James, with the highest gill raker counts, Mayr, E., the York -Rappahannock, with the lowest counts, 1953. and the Upper Bay, which has intermediate counts . Marr, J. C. 1935. The use of morphometric data in systematic, racial and relative growth studies of fishes . COPEIA (1): 23-31. E.G. Linsley and R.L. Usinger. Methods and principles of systematic zoology. MjGraw -Hill Book Co., Inc., New York. 328 pp. 7. The gill raker counts of samples from the western end of Long Island Sound were in- termediate between those of Chesapeake Bay and those of the Hudson River. 8. California and Hudson River speci- mens both have high gill raker counts . 9. The Delaware River population is approached most closely by the James River sub- population from Chesapeake Bay. 10. Samples from the Santee-Cooper River System, South CaroUna have the lowest mean gill raker counts, while those from the Hudson River have the highest counts along the Atlantic Coast. McGregor, E. A. 1924. A possible separation of river races of king salmon in ocean caught fish by means of anatomical characters. Calif. Fish and Game 9 (1923): 138-150. McHugh, J. L. 1951. Meristic variations and populations of northern anchovy (Engraulis mordax mordax). Bull. Scripps Inst. Ocean. 6(3): 123-160. Merriman, D. 1937. Notes on the Life history of the striped bass (Roccus lineatus). COPEIA (1): 15-36. 11. It is shown that gill raker counts can be used to separate populations of striped bass. LITERATURE CITED 1941 . Studies on the striped bass (Roccus saxatilis) of the Atlantic Coast. Fish. Bull. U.S. Fish and Wildlife Service. 50(35): 1-77. Ginsburg, I . Pearson, J. C. 1955. Fishes of the family Percophididae 1938. The life history of the striped bass. from the coasts of eastern United States and the West Indies, with descriptions of four new species . Proc. U.S. Nat. Mus. 104(3347): 623-639. or rockfish, Roccus saxatilis (Walbaum). Bull. U. S. Bur. Fish. 49(28): 825-851. Raney, E.G. 1952. The life history of the striped bass, Roccus saxatilis (Walbaum). Bull. Bingham Oceanogr . Coll. 14(1): 5-97. 14 Raney, E. C. and D. P. de Sylva. 1953. Racial investigations of the striped bass, Roccus saxatilis (Walbaum). Jour, of Wildl. Mgt. 17(4): 495-509. , W.S. Woolcott and A.G. Mehring. 1954. Migratory pattern and racil struc- ture of Atlantic Coast striped bass. Trans. Nineteenth N. Amer. Wildl. Conf.: 376-396. Snedecor, G. W. 1946. Statistical methods, 4th ed. Ames, Iowa, Collegiate Press, 485 pp. Steel, R.G.D. andJ.H. Torrie. Principles and procedures of statis- tics with special reference to the biological sciences . (Manuscript). Svardson, 1952. 1955. Races of the striped bass, Roccus saxatilis (Walbaum), in south- eastern United States . Jour . Wildl . Mgt. 19(4): 444-450. Subpopulations of the striped bass, Roccus saxatilis (Walbaum), in the tributaries of the Chesapeake Bay. (Manuscript). Rounsefell, G.A., and W. H. Everhart. 1953. Fishery science its method and applications. John Wiley and Sons, Inc., New York: 1-444. Scruggs, G.D., Jr. andJ.C. Fuller, Jr. 1955. Indications of a freshwater popula- tion of striped bass, "Roccus saxatilis" (Walbaum), in Santee- Cooper Reservoirs . Proc. South- eastern Assoc. Game and Fish Comm.: 64-69. The coregonid problem . IV. The significance of scales and gillrakers. Ann. Rept. Inst. Freshwater Res., Ehrottninghom , 1 9 9 pp . Vladykov, V.D. and G. Beaulieu. 1951. Etudes sur L'Esturgeon (Acipenser) de la Province de Quebec II . Variation du nombre de branchiospines sur le premier arc brcmchial . NaturaUste Canadien. Quebec 78: 129-154. andD. H. Wallace. Studies of the striped bass, Roccus saxatilis (Walbaum), with special reference to the Chesapeake Bay region during 1936-38. Bull. Bingham. Oceanogr. Coll. 14(1): 132-177. 1952. 1954. Taxonomic characters of the eastern North American chars (Salvelinus and Christivomer). Jour. Fish. Res. Bd. Canada. 9(6): 904. 15 Table 1. — Relation 'between age of striped bass and calculated regression formula based on gill rsdser counts for samples fron several river systems. Mean-Gill Upper Arm~U Regression formula Location Age Rakers Total-T ? = y + b( :x - x) 1952 yr. class York R. 0, I, II 2i^.i+66 T =24.633 - 0.002X York R. 0, I, II 9.5^^8 U = 9.^74 + 0.001.: 1953 yr. class RfippRhflnnnrV R, I 9.750 U = 4.976 -i- 0.022X Rappahannock R. 0 9. 780 U = 9.656 4. 0.002X Rappahannock R» I 9.368 U = 7.976 + O.OO6X Rappahannock R. 0, I 9.679 U = 9.839 - o.ooLx: Rappahannock R. I 2if.833 T =20.493 + 0.020X Rappahannock R, 0 2U.68O T =23.335 + 0.026X Rappahannock R, I 23.789 T =18.651 + 0.024X Rappahannock R, 0, I 24.!j9^ T =24.757 + 0.002X Albemarle Sd, 0, I 2J^.S24 T =24.938 - O.OOIX Santee -Cooper II 22.il 21 T =26.654 - 0.015X Santee-Cooper I 23.326 T =25.081 - 0.013X Santee "Cooper I, II 23.074 T =24.252 - 0.007X Santee -Cooper I 9.184 U = 8.576 + o.oo4x Santee -Cooper II 8.789 J =12.441 - 0.013X Santee -Cooper I, II 9.074 U =13.820 - 0.003X I95I+ yr. class Pamunkey R. 0 9.020 77 = 8.4l6 + 0.012X York R. I 9.039 u = 9.287 + O.OOIX York & Pamunkey 0, I 9.030 u = 9.000 + 0.0002X Pamunkey R. 0 23.940 T =22.581 + 0.027X York R. I 23.745 T =26.033 -• 0.012X York & Pamunkey 0, I 23.842 T =■24.000 - O.OOIX James R. I 24.432 T =23.127 + 0.007X Chickahomicy 0 24.439 T =24.250 + 0.004X James & Chickahominy 0, I 24.435 T =24.419 + O.OOOIX 16 Table 2.— The total number of gill rakers in the sexes in a aample from 72 to 198 mm. S.L. taken in the Delaware Riyer, New Jersey on October 9, 1952. Total No. Gill Rakers Sex 25 24 25 26 27 Nc. Me&n S( X - x)- Male 3 17 13 13 3 h-9 2h,91d "',0',-, Female 6 6 12 7 = 31 -.045 33.097 t = 1.13, N.S. 17 Tatle 3.— Total number of gill rakers of young striped bass of the 1955 year class from the tributaries of the Chesapeake Bay River 21 Total No. Gill Rakers 22 23 2k 25 26 27 28 No, Mean S(X - x) ^^2 Susquehanna - 1 10 27 15 7 - 60 24.283 52.183 Elk - - 3 20 21 k 1 49 24.592 31,837 Sassafras - - 11 22 26 k - 63 24,365 44.503 Middle - - 1 8 5 1 - 15 24.400 7.600 Back - - 7 17 16 1 - 41 24.268 24.049 Patapsco - 2 8 12 17 9 . 48 24.479 57.9-^9 Chester - 1 5 29 22 7 1 65 24.492 52.246 Severn - - 2 12 19 2 - 35 24.600 16.400 Miles - - 8 13 12 5 „ 38 24,368 34.3'42 Choptank - - 1 Ik 21 7 1 kl^ 24.841 27.886 Patuxent - 1 11 30 10 1 - 53 23.981 28.981 liaaticoke 1 - 17 24 29 5 1 77 24.286 77.714 Wicomico - 1 3 Ik 23 9 _ 50 24.720 40.080 Potomac - 2 19 81 61 14 1 178 24.388 126.253 Rappahannock - 2 9 20 18 1 - 50 24.140 38.020 Pamunkey - 7 11 16 12 4 - 50 23.900 66,500 James - 1 2 11 k2 23 4 2 85 25.224 80.753 Analysis of Variance Source d,f. s. s. M.S. I Among Rivers 16 101.247 6.3279 7»71** Error 98Jt 807.926 0.8211 18 Table h. — Number of gill rsikers on the upper arm of young striped bass of the 1955 year class fron the tributaries of the Chesapeake Bay River Upper Arm 7 8 9 10 11 12 Nc. Mean S{X - xf - 1 30 23 6 60 9.567 28.733 - 1 22 25 1 h9 9.531 16.204 - ]_ 26 35 1 63 9.571 19.'^29 - - 8 7 ^ 15 9.h6l 3.733 - 1 20 18 2 41 9.512 16.244 - - 16 27 5 48 9.771 18.479 - 1 31 31 2 65 9.523 22.215 - - 14 21 ~ 35 9.60c 6.400 - - 22 14 2 38 9.^74 13.47ii. - 1 15 27 1 ^ •» 44 9.636 Ii:.l82 - 2 kl 10 „ 53 9.151 10,792 - 1 h2 32 1 77 9.390 34.' . - i 16 31 2 50 9.68c l^.SSo - 2 84 88 4 178 9.528 56.360 - 5 23 22 - 50 9.340 21.220 k 10 28 8 " 50 8.800 32.000 - 1 12 50 21 1 85 10.106 40.047 Analysis of Variance M .s. d.f. s.s. F. 16 70.735 4.4209 11.67** 98k 372.704 0. 3788 Susquehanna Elk Sassafras Middle Back Patapsco Chester Severn Miles Choptank Patuxent IJasiticoke V/icomico Potomac Rappahannock Pamunkey James Source Among Rivers Error 19 Table 5.— Analyses of variance of total number of gill rakers of young striped bass of the 1955 year class from the tributaries of the ChesapeaJce Bay (see Table 3) A Excluding the Rappahannock, York, and James River Systems Source d.f. S.S. M.S. X Among Rivers 13 29.513 2.2702 2.92** Error 802 622.653 O.Tlbh B Excluding the Patuxent, Rappahannock, York and James River Systems Source d.f. S.S. M.S. _P Among Rivers 12 18.821 1.5684 1.98* Error 750 593.672 O.7916 C Excluding thie Wicomico, Patuxent, Rappahannock, York and James River Systems Source d.f. S.S. 'M.S. F_ Among Rivers 11 1^4-. 792 1.3ij47 1.70 K.S. Error 701 553.592 O.7S97 20 Table 6. — Analyses of variance of the number of gill rakers on the upper arm of young striped bass of the I955 year class from the tributaries of the Chesapeake Bay (Table k) A Excluding the Rappahannock, York, and James River Systems Source d.f. S.S. M.S. P Among Rivers 13 14.073 I.O825 3.10** Error 802 279.43? 0.3484 B Excluding the Patuxent, Rappahannocky York and James River Systems Source d.f. S.S. M.S. F Among Rivers 12 6.162 0.5153 .1.43 U.S. Error 750 268.645 O.3582 21 Table 7.— Total number of gill rakers of young striped bass of the 1955 year class from the tributaries of the Chesapeake Bay A Total No. Gill RaJters River 22 23 2k 25 26 No. Mean S(X -x)2 Rappahannock 2 9 20 18 1 50 24.140 38. 020 Pamunkey 7 11 16 12 k 50 23.900 ee. 500 t = 1,16 N.S. B Total No. GiUL Rakers River 22 23 2k 25 26 27 28 No. Mean S(X - x)2 Rappahannock and Pamunkey 9 20 36 30 5 - - 100 24.020 105.960 James 1 2 11 k2 23 4 2 85 25.224 80.753 t = S-Oai^* c Totai . No. Gill Rakers River 22 23 2k 25 26 27 28 No. Mean S(X - X)2 Chickahominy - 1 2 11 9 3 1 27 25.518 28.741 James 1 1 9 31 14 1 1 58 25.086 48.569 t = 1.92 H.S. 22 Table 8.— A comparison between samples from the east and west shore (excluding the York, Rappahannock, and James River Systems) tributaries of the Chesapeake Bay of young striped bass of the 1955 year cl^ss A Total No. Gill Rakers Rivers 21 22 23 2k 25 26 27 No. Mean S(X - x)2 West Shore - 6 58 187 1^+3 35 1 kzo 24.340 324.428 East Shore 1 2 kd 136 15^^ 111 k 386 24 « 500 322 . 500 t = 2.56* B l^per Ann Rivers 6 7 8 9 10 11 Mb. Mean S(X - x)2 West Shore - - 6 213 19k 17 .'+30 9.516 153.386 East Shore 1 - 6 174 195 10 386 9.534 l40,062 t = 0A3 N.S. 23 Table 9.— A comparison of the total number cf gi.Li rakers between samples from up- and downstream sireas of the York and James River Systems for the 1954 year cJass A Total No. Gill Rakers RiTCr 21 22 23 24 25 26 No. 14ean S(X .. x)2 York - yx. - 5 16 16 9 3 5i 23.745 55.686 Pamunkey - yg. 1 3 15 16 9 6 50 23.9^0 68.820 t = 0,87 N.S. B Total No. GiLl Rakerfc Rii/er 21 22 23 24 25 26 27 M-j. Hjan S(X - x)^ Jeimes - yr. 1 3 5 11 24 7 - 51 24.470 66.706 Chickiihominy- yg. - 1 3 17 .13 1 1 41 24.429 30.098 t = 0,14 N.S. 24 Table 10.— -A comparison of samples of the 1953 yesz- c"^es within the same rive: system. A Total No. Gill Rakers Rappal:iaimock 22 23 2k 25 26 NOo iMean S(X - xf Yearling 1 9 11 10 k 35 24.200 37.600 Young - 6 10 23 6 50 2k. 660. 34.88c t = 2.33* B Upper Arm Rappahannock 6 9 10 11 Ko. i^ean S(X .■ 3:)2 Yearling 1 Ik 20 " 55 9-5^3 10.686 Young - Ik 33 3 50 9.780 14-560 t = 1.95 N.S. C Upper Arm River 7 8 9 10 11 No. Mean S(X - x)2 York - yr. 3 k k5 25 2 79 9.240 44.430 Mattaponi - yg. - - 7 9 - l6 9.562 3.938 t = 1.63 N.S. 25 Table 11.— Total number of glU rakers from samplee of striped base of the I953 year class from the tributaries of tbe Chesapeake Bay A River Total Do. GlU Rakers 21 22 23 2if 25 26 No. Mean S(X - x) ^\2 York - yr. tfettaponi - yg. t = 2.83«* 17 25 19 5 79 23.772 123.899 691 16 24.688 5A38 B River Total No. Gill Rakers 21 22 23 2k 25 26 No. Mean S(X - x)2 York - yr. Rappahannock- yr. t = 1.75 N.S. 9 17 25 19 5 1 9 11 10 k 79 23.772 123.899 35 2U.200 37.600 Table 12.— An amalysis of covariance of the total nuniber of gill rakers for seuiiples of the 1953 year class from the York River System Source d.f. 3x2 Sxy 3y2 Y adjusted for X d.f. S.S. M.S. Total 9k 23357'*-358 -1813. if53 140.484 Samples 1 201292.736 -1498.002 11.147 Error 93 32281.622 - 315.451 129.337 92 126.255 1.3723 Samples + Error 94 233574.358 -l8l3.453 140.484 Samples adjusted F = O.U N.S. 93 126.404 1 0.149 0.149 26 Table 13.— An analysis of veiriance of the total number of giLI i-aiccra for sanples of striped bass from the 1952 year class from the York River System River Total No. Gill Rakers 22 23 21+ 25 26 27 No. Wean S(X - x)' York - yr. 2 2 3 - - 7 2^.143 if. 857 York + Pamunkey - yg. 9 16 11; 9 2 50 2l;.58C 60.16c Paniunlcey - yr. 1 1 8 5 1 - 16 211.250 13.000 Source d.f. s.s. li-.Sr F Among Samples 2 2.127 1.0635 G.95 N.S. Error 70 78.037 ■L.Hhd Table 14.— An aimlysis of variance of the total nuraber of gill ral;ors for samples of the 19l|-9 year clast; of striped uass fi-om the Cheoapeake Bay at Crisfield, Jferyland Sample Total No. Gill Rakers 23 2I+ 25 26 27 No. ^fean S(X - x) ^\2 A - yg- - 5 5 2 - 12 2lf.750 6.250 B - yg- 2 3 3 3 11 24.636 I2.5I+6 C - yg- 3 7 21 7 1 39 21^897 29.590 Source d.f. S.S. M.S. F Among Samples 2 0.662 0,3310 0.1+0 N.S. Error 59 1+8.386 0.8201 27 Table 15 . — An analysis of variance of the total number of gill rakers for ssiniples of striped bass from the James River, Virginia Total Ho. Gill Rakers Year Class 20 21 22 23 2k 25 26 27 28 No. Mean S{X -x)2 19^9 - yg- - 2 2 8 5 1 - - 16 2'+.056 13.944 1952 - yr. - - 1 k 11 1 - - 17 24.706 7.530 1953 - yr. 1 1 3 12 18 17 2 - - 5^^ 23.926 73.704 195^+ - yg--yr. 1 k 8 28 k2 8 1 - 92 24.1+56 96.826 1955 - yg- - 1 2 11 42 23 k 2 85 25.224 80.753 Source d.f. S.S. K I.S. F Among ; year classes k 6k .923 16.2308 15.25** Error 261 277.757 1. 06it2 Table I6. — ^An einalysis of variance of the total number of gill rakers for samples of striped bass from the Santee -Cooper River System, South Carolina Total No. Gill Rakers Year Class 21 22 23 24 25 26 No. Mean S(X - x)^ 1953 - yr. - 8 20 18 3 h9 23.326 32.776 1953 - yr. 3 6 9 1 - 19 22.421 12.632 1954 - yg- - 3 8 25 12 2 50 24.040 39.920 1954 - yr. 1 3 6 3 1 14 23.000 14,000 1955 - yg. - 5 20 22 7 1 55 23.618 42.982 Source d.f. S.S. M.S. F_ Among year classes 4 42.407 10.6018 13.56** Error 182 142.310 0.7819 28 Table I7.— A "Homogeneity of Within Sample Regression" of the total number of gill rakers for samples of striped bass from the Santee-Cooper River System, South Carolina Year Class d.f . Sx2 Sxy sy2 d.f. Reduced S.S. 1953 - yr. U8 1277^.980 -163.326 32.776 hi 30.688 1953 - yr. 18 7831.790 -116.158 12.632 17 10.909 195^ - yg. h9 6530. 1|20 85.920 39.920 k8 38.790 1954 _ yr. 13 J+I57.21I1 105 . 000 ll+.OOO 12 11.3i^8 1955 - yg. 5^ 600k. 127 96.636 42.982 53 4l.i4-27 Residuals from individual regressions Totals for single regression l82 37299-131 8.072 Difference for homogeneity of regressions 142.310 177 135.162 181 142 . 308 k 9.146 F = _2,146A 133.162/177 = 3.03* Table I8.— An analysis of covariance of the total number of gill raJcers for adjusted sample means of striped bass from the Santee-Cooper River System Source d.f. 3x2 Sxy sy2 Y adjusted for X d.f. S.S. M.S. Total Samples Error 186 4 182 993175.658 955876.527 37299-131 -5832.166 184.717 -5840.238 42.407 8.072 142.310 181 142.308 0.786 Samples + Error I86 Samples adjusted F = 2.60* 993175.658 -5832.166 184.717 185 150.469 4 8.161 2.040 29 Table I9.— A "Homogeneity of Within Sample Regression" of the number of gill rakers on the upper arm for seuiqjles of striped basa from the Santee- Cooper River System Year Class d.f. Sx2 Sxy sy2 d.f. Reduced S.S. 1953 - yr. 1+8 1277^.980 57.816 15.347 47 15.085 1953 - yr. 18 7831.790 -102.421 15.158 17 13.819 l95i^ - yg. 49 6530.420 55.900 18.500 48 18.022 1954 _ yr. 13 4157.214 94.072 8.357 12 6.228 1955 - yg. 5^^ 6004.727 57.818 19.746 53 19.189 Residuals from individual regressions 177 Totals for I82 37299.131 I63.I85 77.108 I8I single regression Difference for homogeneity of regressions 4 F = ^tI^^iyy = 2.48* (Tabulated .05 = 2.42) 72.343 76.394 4.051 Table 20. — An analysis of covariance of the number of gill rakers on the upper arm for adjusted san5)le means of striped bass from the Santee-Cooper River System. Y adjusted for _x_ Source d.f. Sx2 Sxy sy2 d.f. S.S. M.S. Total 186 993175.658 -2272.545 83.818 Samples 4 955876.527 -2435.730 6.710 Error 182 37299.131 163.185 77.108 181 76.394 0.422 Samples + Error 186 993175.658 -2272.545 83.818 185 78.618 Samples adjusted 4 2.224 0.556 F = 1. .32 N.S. 30 Table 21. — Total number of gill rakers of young striped bass of the I954 year class from the Hudson River, New York Total Ho. Gill Rakers Locality 23 2k 25 26 27 28 29 No. Mean S(X - x)2 Coxsackie 1 7 38 72 22 12 - 152 25.9^1 ikkMl Haverstraw 2 13 31 h3 18 3 - UP 25.652 in.k2o Harmon - k 13 18 11 2 - k8 25.875 U7.250 Croton Pt. - 2 10 5 2 - - 19 25.368 12.421 Nyack 1 1 19 35 20 k 1 81 26.086 76.395 Palisades State Park 1 6 31 20 7 3 - 68 25.515 66.985 Analy! 3is of Veiriance Source d.f. S.S • M.S. F_ Among localities 5 21.429 J+.2858 k.55** Error klh 46if. 938 0.9809 31 Tatle 22. — The number of gill rakers on the upper arm of young striped bass of the 1954 year class from the Hudson River, New York Upper Arm Locality 8 9 10 11 12 No. Mean S(X - Tlf Coxsackie 1 8 55 16 12 152 10.592 82 . 711 Haverstraw - 11 kd J^9 k 112 10.1^11 57.107 Harmon - 2 17 19 10 1^8 10.771 32.479 Croton Pt. - 2 12 5 - 19 10.158 6.526 Kyack - 1 29 h9 2 81 10.642 24.617 P&lisades State Park 1 5 33 25 k 6Q 10.382 40.059 Analysis of Variance Source L, d ..f. S.S. M.S. F Among localit ies 5 10.093 2.0186 3.92** Error klk 2i^3.J+99 0.5137 Table 23. — Total number of gill rakers of young striped bass of the 1954 year class from the Hudson River, New York Locality Total No. Gill Rakers 23 24 25 26 27 28 29 No. Mean S(X - "x)^ 25.9^1 144.467 25.747 337.997 A 1 7 38 72 22 12 - 152 B 4 26 104 123 58 12 1 328 t = 1.968 (tabulated value at .05 = I.965) Locality A - Coxsackie Locality B - Haverstraw, Harmon, Croton Pt., Nyack and Palisades State Park 32 Table 24.— Total number of gill reikers of young striped "bass of the 1953 year class from the Hudson River, New York Total Ho. Gill Rakers Locality 22 23 2k 25 26 2? 28 No. Mean S(X - x)^ Coxsackie - 1 1 10 21 15 2 50 26.O8O J^5.680 Haverstraw 1 - 1 I9 20 13 1 55 25 -818 5*^.182 t = 1.36 N.S. Table 25.— An analysis of variance of the total number of gill rakers of young striped bass of the 19^9 year class from the Hudson River, New York Total No. Gill Rakers Locality 2k 25 26 27 28 Ho. Mean S(X - x)2 1) Port Ewen - 5 k 3 12 25.833 7.667 2) Stony Point and Haverstraw 1 5 5 2 13 25.615 9.077 3) Stony Cove and Haverstraw 2 Ik Ik 3 1 34 25.618 24.030 4) Stony Point - 6 7 8 21 26.095 13.810 • Source d t.f. S.S. J! I.S. X Among localities 3 3.366 1. 122 1 .56 N.S. 1 vs. 2, 3, k 1 0.048 0. 048 0 .07 N.S. Error 76 54.584 0, 718 33 Table 26. — An analysis of variance of the total number of gill rakers for samples from six year classes of young striped bass from the Hudson River, New York Total No. Gill Rakers Year Class 22 23 24 25 26 27 28 29 Ho. Mean S(X - x)2 1936 - - 1 15 18 2 - 1 37 25.676 26.108 19^9 - - 3 30 30 16 1 - 80 25.775 57.950 1950 - 1 1 13 16 4 1 - 36 25.667 30.000 1952 - 1 3 6 9 - - - 19 25.210 15.158 1953 1 1 9 42 hS 32 3 1 137 25.788 140.861 195*^ - 5 33 142 195 80 24 1 480 25.808 486.367 Source d .f. S_ .s. M.S. JL Among year c lasses 5 7.399 1.4798 1 .53 N.S. Error 783 756.444 0.9661 34 Table 2?. — ^A comparison of the total number of gill rakers between samples of striped bass from the James River, Virginia with those from the Hudson River, New York A Total No. Gill Rakers 1954 Year Class 21 22 23 2k 25 26 2? 28 29 No. Nfean S(X - x)^ James R.- yg.-yr. 1 it 7 28 39 5 1 - - 85 2it.400 86.400 Hudson R. - yg. - - 5 33 1^2 195 80 24 1 48o 25.808 486.367 t = 11.87** B Total No. Gill Rakers 1953 Year Class 20 21 22 23 24 25 26 27 28 No. Mean S(X - x)^ James R. - yr. 1 1 3 12 I8 14 1 - - 50 23.820 65.38O Hudson R. - yg. - - 1 1 9 42 49 32 3 137 25-788 l40.86l t = 11.28** Table 28. — An analysis of variance of the total number of gill rakers of yearling striped bass from five year classes from the western end of l£ing Island Sound Total : No. Gill Rakers Year Class 23 24 25 26 27 28 Kb. Mean S(X -lc)2 1949 2 5 7 2 1 - 17 24.706 17.530 1950 - 1 6 3 - - 10 25.200 3.600 1951 1 4 4 2 - - 11 24.636 8.546 1952 1 1 4 1 - 1 8 25.125 14.875 1953 1 4 12 8 - - 25 25.080 15.160 Source d.f. J 3.S. M.S. -L Among year classes 4 3 .384 0 .8460 0.94 N.S. Error 66 59 .711 0 .9047 35 Table 29- — A comparison of the mean values of total gill rakers for seven year classes of striped bass from the Hudson River, western Long Island Sound and the Chesapeake Bay Year Year Year Class Hudson R. Class Long Island Sd. Class Chesapeake Bay 195it 25.808 •i^9-'53 2k.9hh 1955 2k.kkk 1953 26.060 1953 25.080 1953 24.241 1952 25.210 1952 25.125 1952 24.381 1951 - 1951 24.636 1951 23.400 1950 25.667 1950 25.200 1950 - 19^9 26.095 19*^9 2k . TO6 1949 24.256 36 Table 30. — ^An analysis of variance of the total number of gill raJcers of young striped bass of five year classes from the upper Chesapeake Bay Total Wo . Gill Rakers Locality 21 22 23 24 25 26 27 No. Mean S(X - xf A 1 7 95 293 287 75 5 763 24.446 612.493 B - 1 2 2 11 1 1 18 24.667 22.000 C - - 5 15 29 12 1 62 24.822 49.048 D - 1 5 12 12 3 1 34 24.412 36.235 E - - 3 6 7 6 - 22 24.727 22 . 364 Source d.f. s .s. h I.S. F Among localities k 10 .307 2. 5768 3 .10* Error m 742.140 0. 8301 A - Upper Chesapeake Bay population not including the Patuxent River; 1955 year class B - Potomac River 1948 year class C - Crisf ield, Maryland I949 year class D - Crisf ield, Maryland 1951 year class E - Crisfield, Maryland 1952 year class 37 Table 31.— An analysis of variance of the number of gill rakers on the upper arm of young striped bass of five year classes from the upper Chesapeake Bay Upper Arm Locality* 6 7 8 9 10 11 No. Msan S(X - x)2 A 1 - B - - C - - D - - E - - Source Among localities Error * Locality designations are the same as in table 30. 10 31^6 379 27 763 9.550 27'*.807 1 h 12 1 18 9.722 7.611 - 25 35 2 62 9.629 18.1^68 1 17 Ik 2 5k 9.500 U.500 9 U 2 22 9.682 8.773 d.f. S.S. M.S. F k 1.287 0.3218 0.89 N. 894 324.159 0.3626 38 Table 32. — An analysis of variance of the total number of gill rsQcers of young striped bass from three year classes from California Total No . Gill Rakers Year Class 23 2k 25 26 27 28 29 No. Mean S(X - x)2 19^3 - 2 11 5 2 - - 20 25.350 12.550 19^5 1 1 16 33 17 k 1 73 26.096 70.329 1945 2 3 19 20 15 3 - 62 25.839 74.387 19^*5 - 2 16 14 15 3 - 50 26.02c 50.980 19^5 - - 7 5 k - - 16 25.812 10.438 1951 Source 2 6 23 9 3 d.f ; s, .S. 43 25.116 M.S. 34.419 Among : year classes 5 33 .018 6.6036 6.73** Error 258 253. ,103 0.9810 39 Table 33. — A chi-square test of the number of gill rakers on the upper arm for samples of young striped bass from three year classes from California Upi^er Arm Year Class 8 9 10 11 12 No. *fean 19^3 19^5 19^5 1951 X^ = 27.i+3** 1 Ik 5 - 20 10.200 3 31 5h 5 73 10.562 3 36 21 1 62 10.290 - 26 2k - 50 lO.J+80 1 5 10 - 16 10,562 2 34 6 ^ 43 10.046 Table 34. — ^An analysis of variance of the total number of gill rakers of young striped bass of the I945 year class from California Total No. Gill Rakers Sample 23 24 25 26 2? 28 29 No. Mean S(X -x)^ A 1 1 16 33 17 4 1 73 26.096 70.329 B 2 3 19 20 15 3 - 62 25.839 74.387 C 2 16 14 15 3 - 50 26.020 50.980 D - 7 5 4 - - 16 25.812 10.438 Source d.f. S.S. J Ji.S. L Among samples 3 2.742 0 .9140 0.87 N.S. Error 197 206.134 1 .0464 40 Table 35. — A comparison of total number of gill rakers of young striped bass from California with those from the upper Chesapeake Bay and Hudson River A Locality Total No. GiU Rakers 21 22 23 2k 25 26 2? 28 29 Chesapeake Bay California t = 20.45** 1 9 110 328 346 97 8 - - - 3 6 58 72 51 10 1 No. Mean S(X - x)2 899 24.482 752.447 201 25.975 208.876 B Locality Hudson R. California t = 2.56* Total No. Gill Rakers 22 23 24 25 26 27 28 29 1 8 50 248 317 134 29 2 - 3 6 58 72 51 10 1 No. Mean S(X - x) T.s2 789 25.774 765.110 201 25.975 208.876 41 Table 36. — A comparison among samples of three year classes of yearling striped bass from the Miramichi River, New Brunswick A Total No. Gill Rakers Year Class 21 22 23 2k 25 26 No. Mean 1952 1 ^ 29 U 2 - 50 23.240 1953 - 3 8 11 6 - 28 23.71'* 1955 - 1 26 17 10 1 55 23.709 x2 = 13.^+0* B Year Class 8 9 10 11 No. Mean Upper Ann 8 9 10 3 2k 22 2 12 Ik 2 31 20 1952 3 2i+ 22 1 50 9.'*20 1953 2 12 li^ - 28 9.1+28 1955 2 31 20 2 55 9.'*00 X^ = 1.75 N.S. 42 Table 37.— A ccMparison of striped bass from the Mlramichl River with those from the Philip and St. Lawrence Rivers A River Total No. Gill Rakers 22 23 2k 25 26 No. {fean S(X - x)^ Miramichi Philip t = 1.28 N.S. 1 26 17 10 1 6 26 22 k 2 55 23.709 39.346 60 23.500 U7.OOO B River Upper Arm 8 9 10 11 7 67 56 13 1 13 38 10 lib. Mean S(X - Ic)^ Miramichi St. Lawrence t = 3.66** 143 9.524 75.664 62 9.919 26.597 C River Total No. Gill Rakers 21 22 23 24 25 26 No. Mean S(X - "x) ■^\2 Miramichi Philip t = 0.25 N.S. 8 63 42 18 1 6 26 22 4 2 133 23.534 97.098 60 23.500 47.000 43 Table 38. — An analysis of variance of the total number of gill rakers of striped bass of several year classes from the Delaware and Maurice Rivers, New Jersey Year Class Total No. GiLL Rakers and River 23 24 25 26 27 No. Mean S(X - x)2 1952 Delaware - yr. 2 8 10 17 2 39 25.231 38.923 1951 Delaware - yr. 9 24 25 22 3 83 24.831 91.639 1954 Maurice - yg. - 2 9 5 16 25.188 6.438 Source d.f. s.s. M.S. F Among samples 2 4.971 2.4855 2.45 N.S. Error 135 137.000 1.0148 44 Table 39. — An analysis of variance of the total number of gill ralcers of striped bass from the Albemarle Sound Total No. Gill Rakers Year Class I9 20 21 22 23 2k 25 26 2? No. Mean S(X -Ic)^ 1953 - yg. - - 1 9 17 7 - 34 24.882 19.530 195^ - yg. - - 1 2 8 2 3 16 25.250 19.000 1951 - yr. 1 - - k 11 7 2 1 - 26 23.231 42.615 1953 - yr. - - 1 5 9 2 - 17 24 . 706 9.530 19h6 - yg. - 2 - 8 14 1 - 25 24.480 20.240 19^6 - yg. - - 1 3 8 7 1 - 20 24.200 17.200 1952 - yr. - - k 11 11 1 " 27 24.333 16.000 1955 - yg. - - 1 h 14 18 3 1 41 24.512 36.244 1953 - yr- - - 9 15 18 2 - hrk. 24.295 31.159 Source d.f. S .s. M.S. ?_ Among saii5)les 8 58.678 7. ,3348 B.36** Error 2iH 211.518 0. .8777 45 Tatle 40.— A chi-squeure test of the number of gill rakers on the upper arm of striped bass collected from the Albemarle Sound Year Class Upper Arm 8 9 10 11 1953 - yg. 195^ - yg. 1951 - yr. 1953 - yr. 19^6 - yg. 19^6 - yg. 1952 - yr. 1955 - yg. 1953 - yr. X^ = 50.95** 2 1 15 3 3 8 5 12 18 28 11 8 13 18 11 18 25 2k k k 2 1 2 1 k 3 2 No. Mean 5k 10.059 16 10.188 26 9.423 17 9.882 25 9.800 20 9.650 27 9.963 41 9.732 kk 9.636 Table kl. — .A.n analysis of variance of the totsuL number of gL'J, rakers of striped bass of the I953 year class from the Albemarle Sound Total No. Gill Rakers 1953 Year Class 23 2k 25 26 No. Mean S(X - x)^ A - yg. 1 9 17 7 34 24.882 19.530 B - yr. 1 5 9 2 17 24.706 9.530 C - yr. 9 15 18 2 44 24.295 31.159 Source d.f. S.S. M.S. F_ Among samples 2 6.939 3.4695 5.30»« Error 92 60.219 0.6546 46 Table h2. — An overall relationship between the sample means of the total number of gill rakers of striped bass and their geographical location Clas£ i Means* of the Total No . Gill Rakers 22 23 2k 25 26 Locality .5 . ,8 .1 .h • 7 .0 .3 .6 .9 .2 .5 .8 .1 A St. Lawrence R. 1 Mlramichi R. 1 2 Philip R. 1 1 Rhode Island 1 1 Western L.I. Sd. 1 2 1 1 Hudson R. 1 2 11 8 7 2 Mullica R. 1 Delaware R. 1 1 ^5Burice R. 1 Chesapeake Bay Susquehanna R. 2 Elk R. 1 Sassafras R. 2 Middle R. 1 Back R. 2 Patapsco R. 1 1 Chester R. 1 2 Severn R. 1 Miles R. 2 Choptank R. 1 Patuxent R. 1 2 1 Nanticoke R. 1 1 Wicomico R. 1 Potomac R. 1 1 3 3 1 Crisfield, M. 1 2 3 Rappa,hfl.nnnck R. 1 2 2 1 York R. System 1 h 3 1 James R. System 1 1 3 1 3 1 Hbrfolk, Va. 1 Albemarle Sd. 1 2 3 1 1 Little R. 1 Roanoke R. 1 1 Chowan R, 1 Pamlico R. 1 Cape FeeLT, N. C. 2 Santee -Cooper R. 1 2 3 2 3 1 Ashley R. 1 Broad R. 1 Gulf of Mexico 1 1 California 1 2 3 ♦Example - Class Mean 24.3 Includes means 2it-.2 to 24. U Numbers in the body of the table refer to the number of samples counted 47 Tabls 43. — An overall relationship between the sample means of the number of gill rakers on the upper arm of striped bass and their geographical location Class Means* of the No. Gill Rakers on Upper Arms 8 Locality .85 9 .05 .25 .^5 .65 .85 10 .05 .25 .45 .65 11 .85 .05 St. Lawrence R, Miramichi R. Philip R. Rhode Island Western L.I. Sd. Hudson R. Muilica R. Delaware R. ^feurice R. Chesapeake Bay SusqueVianna R. Elk R. Sassafras R. Middle R. B8.ck R. Patapsco R. Chester R. Severn R. Miles R. Choptank R. Patuxent R. Nanticoke R. Wicomico R. Potomac R. Crisfield, Md. Rappahannock R. York R. System James R. System Norfolk, Va. Albemarle Sd. Little R. Roanoke R. Chowan R. Pamlico R. Cape Fear, N.C. Santee -Cooper R. Ashley R. Broad R. Gulf of Mexico California 2 1 2 2 1 k 1 1 1 3 1 1 1 1 1 2 1 1 1 1 1 k 2 3 2 1 2 1 1 1 1 1 3 1 3 1 1 1 1 1 2 1 5 1 2 10 1 Ik * Example - Class Mean 9.85 includes means 9.8 to 9.9 Numbers in the body of the table refer to the number of samples counted 48 Table 44 . — Compaxisons of the total number of gill rakers of striped bass from the Miramichl River, New Brunswick with those from the Santee-Cooper River System, upper Chesapeake Bay and York -Rappahannock populations 1953 Year Class Totea No. Gill Rakers 22 23 2k 25 No. Mean S(X -~x) ^^2 Miramichi - yr. 3 8 11 6 28 23.714 23.714 Santee-Cooper - yr. 8 20 18 3 49 23.326 32.776 t = 1.89 H.S. B 1955 Year Class Total No. Gill Rakers 21 22 23 24 25 26 27 No. Mean S(X - x) ^\2 Upper Chesapeake Bay - yg. Miramichi R. - yr. t = 6.27** 1 7 78 293 287 75 5 - 1 26 17 10 1 746 24.478 55 23.709 576.157 39.346 1955 Year Class Total No. Gill Rakers 22 23 24 25 26 York -Rappahannock - yg. Miramichi - yr. t = 1.90 N.S. 9 20 36 30 5 1 26 17 10 1 No. Mean S(X - Ic) ^^2 100 24.020 105.960 55 23.709 39.346 49 Table 45. — Comparisons of young striped bass of the I955 yesur class from the Santee-Cooper River System with those from the York-Rappahannock population and the upper Chesapeake Bay population A Total No. Gill Rakers River 22 23 24 25 26 No. Mean S(X- x)2 York -Rappsihannock 9 20 36 30 5 100 24.020 105.960 Santee-Cooper 5 20 22 7 1 55 23.618 42.982 t = 2.43* B Upper Arm River 789 10 No. Mean S(X - x)2 York -Rappahannock ^ 15 51 30 100 9.070 60.510 Santee-Cooper 4 30 21 55 9.309 19.7^ t = 1.965 (tabulated .05 = 1.976) C Total Ho. Gill Rakers Locality 21 22 23 24 25 26 27 No. Mean S(X - x)2 Upper Chesapeake Bay 1 7 78 293 287 75 5 746 24.478 576.157 Santee-Cooper _ 5 20 22 7 1 - 55 23.618 42.982 t = 6.99** 50 Table k6. — Comparisons of young striped bass of the 1955 year class from the Chesapeake Bay and Albemarle Sound A Total Ho. Gill Rakers Locality 22 23 24 25 26 2? No. Mean S(X - x)^ York -Rappahannock 9 20 36 30 5 - 100 2^^.020 IO5.960 Albemarle Sd. 1 it lU I8 3 1 4l 24.512 36. 2H t = 2.623 (tabulated .01 = 2.6l2) B Total No. GiUL Rakers Locality 22 23 2k 25 26 2? 28 No. Mean S(X - x)^ James R. 1 2 11 42 23 4 2 85 25.224 80.753 Albemarle Sd. 1 4 l4 18 3 1 - 4l 24.512 36.244 t = 3.86** C Upper Arm Locality 8 9 10 11 12 No. Mean S(X - x)2 James R. 1 12 50 21 1 85 IO.IO6 40.047 Albemarle Sd. 1 12 25 3 - 4l 9.732 l6.049 t = 2.92** 51 Table 47.— A comparison of the total number of gill rakers of young striped bass of the 1955 year class from the Albemarle Sound with those from the upper Chesapeake Bay and the Santee-Cooper River System A Total No. Gill Rakers Locality 21 22 23 24 25 26 27 No. Mean S(X - x)2 Uppei' Chesapeake Bay 1 7 78 293 287 75 5 746 24.478 576.157 Albemarle Sound - 1 4 14 18 3 1 41 24,512 36,244 t = 0.24 N.S. B Total No. Gill Rakers Locality 22 23 24 25 26 27 No. Mean S(X - x)2 Albemarle Sound 1 4 14 18 3 1 41 24.512 36.244 Santee-Co-^per 5 20 22 7 1 - 55 23.618 42.982 t .= 4.72** 52 I Table 48. — Comparisons of the total number of glU rakers of striped bass from the Chesapeake Bay and the Delaware River ^ A Locality Total No. Gill Rakers 22 23 24 25 26 2? No. Mean S(X - x) ^^2 York-Rappeihannock Delaware t = 7.18** 9 20 36 30 5 - U 34 44 44 100 24.020 105.960 138 24.986 141.971 B Locality Total No. Gill Rakers 21 22 23 24 25 26 27 No. Mean S(X - x) ^^2 Upper Chesapeake Bay 1 7 78 293 287 75 5 1^6 24.478 576.157 Delaware - - 11 34 44 44 5 138 24.986 l4l.971 t = 6.08** C Locality Total Ho. Gill Rakers 22 23 24 25 26 27 28 No. Ifean S(X - x)2 80.753 James Delaware t = 1.72 N.S. 1 2 U 42 23 h 2 - 11 34 44 44 5 85 25.224 138 24.986 141.971 Delaware River sample included young and yearling specimens of the 1951> 1952 and 195^ year classes. Chesapeake Bay samples are young striped bass of the 1955 yesu: class. 53 Table 49. — A comparison of the total number of gill rakers of striped bass from the Hudson and Delaware Rivers River Total No. Gill Rakers 22 23 2k 25 26 2? 28 29 No. Mean S(X - x) ^^2 Delaware - 11 34 1^4 1|4 5 Hudson 1 8 50 248 31? 134 29 2 t = 8.63** 138 789 24.986 25.77^ 141.971 763.843 Delaware River samples included young and yearling specimens of the 1951> 1952 and 1954 year classes. 54 INT.-DUP. SEC, HASH.. D.C;0157 MRl WHOI I ihr.nv