434P DISTRIBUTION OF FISHING BY PURSE SEINE VESSELS FOR ATLANTIC MENHADEN, 1955-59 j Marine Biological Laboratoryf AD-^ A iq\3 WOODS HOLE, MASS. SPECIAL SCIENTIFIC REPORT-FISHERIES Na 434 UNITED STATES DEPARTMENT OF THE INTERIOR, Stewart L. Udall, Secretary FISH AND WILDLIFE SERVICE, Clarence F. Pautzke, Commissioner Bureau of Commercial Fisheries, Donald L. McKernan, Director DISTRIBUTION OF FISHING BY PURSE SEINE VESSELS FOR ATLANTIC MENHADEN, 1955-59 by Charles M. Roithmayr United States Fish and Wildlife Service Special Scientific Report--Fisheries No. 434 Washington, D. C. 1963 Frontispiece: Menhaden purse seine in operation. "Power blocks" haul the net aboard the two purse boats until the fish are concentrated in the bunt. U CONTENTS Page Introduction 1 Distribution of Atlantic menhaden 1 The purse seine fishery 2 Data source and methods of compilation 2 Results 4 Number of purse seine sets by season, month, and area 4 Geographical distribution of purse seine sets by month 7 Apparent fish movements inferred from the distribution of purse seine sets 14 Summary 15 Acknowledgment 15 Literature cited 15 m DISTRIBUTION OF FISHING BY PURSE SEINE VESSELS FOR ATLANTIC MENHADEN,1955-1959 by Charles M, Roithmayr^ Fishery Research Biologist Bureau of Commercial Fisheries U. S. Fish and Wildlife Service Beaufort, North Carolina ABSTRACT The number and location of purse seine sets recorded in logbooks and the num- ber of vessel landings at reduction plants were compiled and estimates made of the total number and distribution of sets for Atlantic menhaden, Brevoonia tyrannus, dur- ing five seasons, 1955-59. Number of sets, by month and area, is given, and varia- tions are noted. Distribution of sets by month is shown graphically. Apparent fish movements were inferred from the distribution of sets. INTRODUCTION One of the objectives of the research by the Bureau of Commercial Fisheries on the Atlantic menhaden, Brevoonia tyrannus, is to determine whether the present rate of fishing exceeds that which would permit the maximum sustainable catch from the population. To ac- complish this objective, continuing measures of fishing effort and catch are required to establish the relation between variations in population abundance and the amount of fishing. Information on the number (a measure of fish- ing effort) and location of sets by the purse seine fleet has been obtained through a log- book system since the inception of the re- search program. This report summarizes the information collected during five fishing sea- sons, 1955-59. The purposes are to (1) record part of the basic effort data from which meas- ures of abundance may be calculated, and (2) show graphically the distribution of fishing. Variations in fishing are discussed, and some inferences concerning the movements of At- lantic menhaden are drawn from the data. DISTRIBUTION OF ATLANTIC MENHADEN Atlantic menhaden are distributed along the Atlantic coast of North America from Nova Scotia to central Florida, but are not equally * Present address: Bureau of Commercial Fisheries, Technological Laboratory, U.S. Fish and Wildlife Serv- ice, Pascagoula, Miss, available throughout the range at all times. During the warmer months, the fish congre- gate in schools which are found in greater concentrations in waters of less than 20 fathoms overlying the inner third of the Con- tinental Shelf. Through the summer, young- of-the-year fish apparently are confined to estuaries, while older fish usually are found in the open waters along the shore and in some of the larger bays. In late autumn, schools of juveniles and adults are found only off the coast of North Carolina, and through most of the winter, the fish seldom are seen in the coastal waters. The reappearance of schools in the inshore waters in spring is coincident with the increase in water temperature. THE PURSE SEINE FISHERY The purse seine fishery for Atlantic men- haden operates on schools which are differ- entially distributed in the inshore waters during two separate periods. The "summer" fishery usually begins between April and June and terminates in October. It is conducted with a fleet of approximately 130 vessels which operate from reduction plants located at 14 ports along the coast (fig, 1) and exploit the species over most of the range. The "fall" fishery, which runs from November through December or January, has a fleet of approxi- mately 60 vessels along the North Carolina coast. Vessels from a given plant usually operate as a group in nearby waters, although those from adjacent plants often fish in the same waters. When fish are scarce, vessels may range considerable distances from their home port. Fishing is conducted during day- light, and catches normally are landed daily. Purse seining for menhaden is conducted from two open purse boats. On the fishing grounds, the two purse boats are lashed to- gether, with the seine divided between them, and towed behind a large carrier vessel. An airplane pilot usually locates the fish and directs the laying of the seine by radio con- tact with the vessel captain. When a school is selected for capture, the seine crews pay out the net while each purse boat completes a half-circle to enclose the fish (see frontis- piece). After the seine is pursed, the crew Figure l.--Locations of menhaden reduction plants and major areas used in summarizing fishing data. hauls in the ends and bottom of the net and the catch is pumped into the hold of the carrier vessel. Most purse boats are equipped with a "power block," a mechanical device for hauling the seine. An average purse seine set yields from about 20 to 25 tons of fish. Detailed de- scriptions of the carrier vessels, purse boats, and gear are given by June and Reintjes (1957, 1959). DATA SOURCE AND METHODS COMPILATION Information recorded in logbooks kept aboard the carrier vessels and records of Atlantic menhaden landings at reduction plants were used to calculate the number and location of purse seine sets in five fishing seasons, 1955-59*. A description of the logbook used aboard the vessel to record catch information was given by June and Reintjes (1959). The number of sets, the location of each set in a unit area of 10 minutes of latitude and 10 minutes of longitude (fig. 2), and an estimate of the quantity of fish caught in each set were recorded for each day's fishing by vessel captains or pilots. Over 500 logbooks, listing catch information on more than 80,000 sets. Figure 2.- -Example of one of the reference charts used in the location of Atlantic Menhaden purse seine catches. were made available for analysis. Additional data were obtained from interviews with crew members of vessels on which logbooks were not kept. It was assumed that (1) each purse seine set recorded in the logbooks was made on a single school of Atlantic menhaden and ' Since purse seine fishing usually is continuous from April through January of the following calendar year, this period is referred to in this report as the annual fishing season. (2) successful and unsuccessful sets were recorded indiscriminately. The total number of vessel landings given in reduction plant records, the corresponding number of vessel landings for which catch information was ob- tained, and the percent coverage for each fishing season are listed in table 1. The number of sets recorded in logbooks of vessels operating from an individual plant was tabulated by unit areas, and by month and TABLE 1. — Daily purse seine vessel landings of Atlantic menhaden, landings for which catch information was obtained, and percent coverage, by season, 1955-59. Vessel Total landings Season vessel for which Coverage landings catch information was obtained 1955 8,822 3,728 42 1956 9,756 A, 352 45 1957 9,345 4,479 48 1958 7,830 4,615 59 1959 9,99-; 6,029 60 Total . . 'i5,747 23,203 51 season. Since logbook coverage was incom- plete, the number of sets made each month in a given unit area by all vessels from a given plant was estimated by the formula; E = n / c \ L. where: E = estimated number of sets in a given unit area n = tabulated number of sets in that unit area c = number of daily landings by all vessels' i = number of daily landings by those vessels from which effort data were obtained Vessels from different plants often fished in the same unit areas during a month; there- fore, the estimated numbers of sets in each unit area by vessels from the different plants were summed to obtain the monthly total for the unit area. Seasonal totals were obtained by summing the monthly unit area totals. These also were ' Equating each vessel landing with a day's fishing is c»nsidered justified, since catches normally are landed at the end of each day's fishing. summed by larger geographical areas. Four such areas were used; these were described by June and Reintjes (1959) in their summary of the biostatistical data on catch (fig. 1) and are as follows: South Atlantic Area: Waters between Cape Canaveral, Fla. and a line running due east from False Cape, Va, (lat. 36°35' N. and long. 75°53* W.). Chesapeake Bay Area; Chesapeake Bay proper and coastal waters outside the Bay lying between False Cape and Great Machipongo Inlet, Va. (lat. 37°22' N. and long 75°43' W.). Middle Atlantic Area: Waters north of great Machipongo Inlet, Va, to a line running due south of Moriches Inlet (lat. 40°46' N. and long. 72°) I' W.) on the southern coast of Long Island, N. Y. North Atlantic Area: Waters along the southern coast of Long Island, east of a line due south of Moriches Inlet, Long Island Sound, and waters north- ward. RESULTS Number of Purse Seine Sets by Season, Month, and Area The number of purse seine sets in the in- dividual season (table 2) varied between 26,522 (1958) and 35,725 (1959). A 20-percent in- crease occurred from 1955 to 1956 and a 5- percent increase from 1956 to 1957; but in 1958 there was a 24-percent decrease, followed by a 35-percent increase in 1959. There were similarities in the monthly dis- tribution of sets among seasons. There was no fishing in February in any season; in two of the five seasons, some fishing occurred in March; and, in four seasons, a relatively small amount occurred in April. In each season, the number of sets increased during the summer and, in four of the five seasons, reached a maximum in July. From June through September, the number of sets re- mained relatively constant from season to season and accounted for between 81 and 84 percent of the seasonal total. Fishing de- creased through the fall months and termi- nated in the following January. In four of the five seasons, however, the number of sets in December exceeded that in November. TABLE 2.— Estimated number of purse seine sets for Atlantic menhaden, by month, 1955-59 (Month of maximum fishing underscored) Itonth Season Ibtal-"- Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Jan. 1955 4 2-48 1,396 5,835 7,289 -4,966 4,459 2,010 943 508 169 27,827 1956 - 202 l,», ^_. ^-^, ~^.,. Z> _ tft 9 N % ■*!•• ^^:. \' %. ^. V".-.i;«yO,^ VfKUV ^3r^^ '^;: '"^•, ^i. '"^- . • . •. ''^*5f»^ T^''^^«^®Si^:::; .;.: P^*^/->f* 3 _ A u M O I- o o / --^ ^ m m u c 'S m u (0 CD g 10 m 3 to B I I • t- u 11 c o ■a 3 00 12 13 ^ 14 15 tC 9» * C uj 01 D 00 i3 I E 18 19 when (1) there was no fishing south of South Carolina, (2) fishing along the Middle Atlantic coast was conducted farther offshore, and (3) fishing did not occur north of Cape Cod. August: The most noticeable changes in the distribution of sets (fig. 10) occurred in 1955 when fishing in Chesapeake Bay virtually was limited to the lower bay, in 1957 when there was no fishing off the Eastern Shore of Vir- ginia, and in 1958 when (1) no fishing oc- curred south of North Carolina and (2) there was little fishing north of Cape Cod. September; In all seasons, the distribution of sets (fig. 1 1 ) was more variable at the ex- tremes of the fishing range. Few sets were made south of Cape Fear; and in two of the five seasons (1957 and 1958), there was no fishing north of Cape Cod. Fishing did not oc- cur along most of the Eastern Shore of Vir- ginia in 1955 and 1957. A reduction in the number of sets was evident along the New Jersey coast in 1958 and 1959. October: The most conspicuous variations in the distribution of sets (fig. 12) occurred within Chesapeake Bay and along the coast of New Jersey. Some fishing was conducted in the vicinity of Cape Hatteras in 1958. November: Distribution of sets (fig. 13) varied slightly during the five seasons. Fishing occurred farther offshore in 1955 and 1959 and was confined largely to the vicinity of Cape Lookout in 1956. Some fishing took place in Chesapeake Bay in 1955, and a few sets were made off the mouth of the bay in 1959. December: The distribution of sets (fig. 14) shows that in 1955 and 1956, fishing was con- centrated in the vicinity of Cape Lookout; while in 1957, 1958, and 1959, it was more widespread and extended from Cape Hatteras to Cape Fear. January; Fishing (fig. 15) was restricted to the vicinity of Cape Lookout in 1956, 1957, and 1958; while in 1959 and 1960, it was more widespread. APPARENT FISH MOVEMENTS INFERRED FROM THE DIS- TRIBUTION OF PURSE SEINE SETS The number and distribution of purse seine sets by month, during five seasons showed a pattern from which movements of Atlantic menhaden may be inferred. The onset of fish- ing, which was determined by the appearance of schools in the surface waters, indicates that a northward coastal movement of fish could have occurred each spring. In every season, fishing began in March or April off northern Florida and off Cape Fear, N. C. In May, fishing began in the vicinity of Cape Lookout, N. C, Chesapeake Bay, and between Delaware Bay and southern Long Island. Fish- ing north of Long Island usually did not begin until June (in 1959 fishing occurred in Nar- ragansett Bay, R. I., in May). The concen- tration of initial fishing in these separate localities in May also suggests an inshore movement of fish toward the larger estuaries. The number and distribution of sets support the hypothesis of a continued northward, coastal movement of fish in late spring and summer. In every season, fishing during April was limited to northern Florida and Cape Fear. Fishing increased in these localities and ex- tended northward to Cape Lookout in May. In most seasons, the number of sets decreased off northern Florida in June, but increased and was more widely distributed off Georgia, South Carolina, and North Carolina. While fishing decreased during the remaining sum- mer months in all localities south of Cape Lookout, there was an increase farther north- ward. In Chesapeake Bay, fishing usually reached a maximum in July, while in the Middle Atlantic Area, the maximum usually was not reached until August. In all seasons, there was comparatively little fishing in the North Atlantic Area until July, particularly north of Cape Cod, Mass. An apparent southward withdrawal of fish from the North Atlantic Area was first evident in August when the number of sets decreased north of Cape Cod and increased in Long Island Sound. Comparatively little fishing oc- curred north of Cape Cod in September, and in 20 only one season (1955), fishing occurred there in October. In the Middle Atlantic Area, the decrease in fishing usually did not occur until September. In October, the distribution of fishing closely resembled that in May. In Chesapeake Bay, fishing remained intense through September in contrast to a decrease farther northward. This was the only area north of Cape Hatteras, N, C, where fishing occurred in November. Entry of fish into North Carolina coastal waters was evident every autumn. The number of sets in November and December approached or exceeded that in any summer month for the South Atlantic Area. In all seasons, fishing occurred farther southward along the North Carolina coast in December than in November. Fishing terminated off Cape Lookout and Cape Fear, which suggests an offshore movement of fish. SUMMARY 1. Compilation and analysis of the number and location of purse seine sets recorded in logbooks by vessel captains or pilots and records of landings at reduction plants during five fishing seasons, 1955-59, fur- nished an estimate of the total number and distribution of sets by purse seine vessels for Atlantic menhaden (Brevoorlia tyrannus). Knowledge of the number and distribution of purse seine sets is essential for calcu- lating measures of abundance and deter- mining the effect of fishing on the popula- tion. 2. Since Atlantic menhaden occur and are caught in discrete schools during the fish- ing season, the purse seine set provides a basic measure for use in calculating fishing effort. 3. Catch information was obtained on 42 to 60 percent of the total seasonal landings. Recorded sets were tabulated, by month and fishing season, in unit areas of 10 minutes of latitude and 10 minutes of longi- tude, and the total number of sets by all vessels was computed. Total seasonal number of sets varied from 26,522 (1958) to 35,725 (1959). Between 81 and 84 percent of the seasonal total was expended from June through September. On the average, 45 percent of the total number of sets during the five seasons occurred in the Middle Atlantic Area; 26 percent in the Chesapeake Bay Area; 18 percent in the South Atlantic Area; and 11 percent in the North Atlantic Area. Grounds heavily fished each season were (1) along the New Jersey and southern Long Island coasts, (2) lower Chesapeake Bay, and (3) off Cape Lookout, N. C. Variations in the number of sets in the different seasons, months, and areas were noted. The number and distribution of sets were used to infer movements of Atlantic men- haden. A northward, coastal movement was indicated in spring, followed by an apparent reversal, beginning in August. Fish entered the coastal waters of North Carolina in November and disappeared by January. ACKNOWLEDGMENT Processing plant operators made their catch records available, and some vessel captains and pilots kept detailed logs of daily fishing activities. LITERATURE CITED JUNE, FRED C. 1961. Age and size composition of the menhaden catch along the Atlantic coast of the United States, 1957; with a brief review of the commercial fishery. U.S. Fish and Wildlife Service, Special Scientific Report — Fisheries No. 373, 39 p. JUNE, FRED C, and JOHN W. REINTJES. 1957. Survey of the ocean fisheries off Delaware Bay. U.S. Fish and Wildlife Service, Special Scientific Report — Fisheries No. 222, 55 p. 21 JUNE, FRED C, and JOHN W. REINTJES. JUNE, FRED C, and JOHN W. REINTJES. 1959. Age and size composition of the 1960. Age and size composition of the menhaden catch along the Atlantic coast menhaden catch along the Atlantic coast of the United States, 1952-55; with a of the United States, 1956; with a brief brief review of the commercial fishery. review of the commercial fishery. U.S. Fish and Wildlife Service, Special U.S. Fish and Wildlife Service, Special Scientific Report — Fisheries No. 317, Scientific Report — Fisheries No. 336, 65 p. 38 p. MS #1200 22 6P0 »33«»« Created in 1849, the Department of the Interior— America's Department of Natural Resources — is concerned with the management, conservation, and develop- ment of the Nation's water, fish wildlife, mineral, forest, and park and recreational resources. It also has major responsibilities for Indian and Territorial affairs. As the Nation's principal conservation agency, the Department works to assure that nonrenewable resources are developed and used wisely, that park and recrea- tional resources are conserved for the future, and that renewable resources make their full contribution to the progress, prosperity, and security of the United States — now and in the future.