THE FISHERY FOR SCUP WITH SPECIAL REFERENCE TO FLUCTUATIONS IN YIELD AND THEIR CAUSES by William C. Neville and Gerald B. Talbot ri Marine Biological Uboratorv L.IBRAR Y '■■ - . 1964 WQOUS HOLE, MASS SPECIAL SaENTIFIC REPORT-FISHERIES Na 459 UNITED STATES DEPARTIflENTjDFJ1j[E_l^^ FISH AND WILDLIFE SERVICE UNITED STATES DEPARTMENT OF THE INTERIOR Stewart L. Udall, Secretary James K. Carr, Under Secretary Frank P. Briggs, Assistant Secretary Jur Fish and Wildlije FISH AND WILDLIFE SERVICE, Clarence F. Pautzke, Commissioner Bureau of Commercial Fisheries, Donald T^. McKeriian, Director THE FISHERY FOR SCUP WITH SPECIAL REFERENCE TO FLUCTUATIONS IN YIELD AND THEIR CAUSES by William C. Neville and Gerald B. Talbot United States Fish and Wildlife Service Special Scientific Report — Fisheries No. 459 Washington, D.C. FOREWORD In 1927, the U.S. Bureau of Fisheries began a study of the marine fishes along the Middle Atlantic States. One of the most important of these was the scup ( Stenotomus chrysops). Em- phasis was placed on this species, but data on others, including weakfish, summer flounder, butterfish, croaker, and sea bass, were collected when practicable. Considerable data were accumulated on scup by 1935, but publication funds were not then available. Later, with the beginning of World War II, fishery research in the Middle Atlantic was suspended and the data were stored. In 1949, headquarters for the Middle Atlantic Fisheries Investigations of the Bureau was established at Beaufort, N.C., with funds allotted for a study of the Atlantic shad. The files from the old Middle Atlantic Investigation were then sent to Beaufort for storage. From time to time, since the 1930's, Federal and State biologists of the Middle Atlantic area urged that this mate- rial be published to aid their studies. The scup information was particularly valuable, for this species is being studied Intensively at the present time by several agencies. All the early material on scup was assembled. This included considerable basic data, tables and figures, and part of a rough manuscript by the senior author of this paper. He was no longer available to complete the manuscript, having accepted employment in a private organization overseas. With his consent the junior author completed the manuscript. In undertaking this task, the junior author has attempted to use all the available data and as much of the old manuscript as possible. Considerable revision was necessary; apparently some material was missing, and data were not available to support all the conclusions reached in the original manuscript. While leaving many questions unanswered, the manuscript, as now presented, furnishes much basic data on the early fishery which should prove valuable to later workers. The conclusions in the manuscript appear sound. The catch of scup in recent years has increased considerably, and in 1960 (the latest figures available), the catch of this species in the Middle Atlantic area, where the bulk of the catch is now landed, ranked second in poundage and fifth in value. Graphs of catches in the New England, Middle Atlantic, and Chesapeake Bay States from 1930 through 1960 are given in the appendix for reference purposes. No attempt has been made to account for the increase in catches or to relate recent catches to the conclusions in the present paper. This presumably will be at- tempted by those who are now studying this fishery. During the revision of the manuscript, valuable help and suggestions were received from James R. Westman, Rutgers University; Paul E. Hamer, New Jersey Department of Fish and Game; Edward C. Raney, Cornell University; and Robert L. Edwards, Bureau of Commercial Fisheries. Editor's note: The basic portions of this report were written in the late 1930's. Use of the present tense refers to that time. References to theU.S. Bureau of Fisheries are correct since the Fish and Wildlife Serv- ice was not established until 1940. li CONTENTS Page Foreword ii Introduction 1 Range 3 Description of the fisheries 4 Pound nets 4 Floating traps 6 Purse seines 7 Otter trawls 8 Handlines 11 Fluctuations in yield and their causes 11 Summer fishery 12 Statistics of the fishery. New Jersey 12 Changes in total yield 12 Measurement of fluctuations 12 Causes of changes in yield 13 Transition from pound nets to offshore vessels 20 Statistics of the fishery. New York and southern New England 24 Changes in total yield 24 Measurement of fluctuations 27 Causes of changes in yield 27 Summary of summer fishei^ 31 Winter trawl fishery 31 Statistics of the fishery 31 Changes in total yield 31 Measurement of fluctuations 32 Causes of changes in yield 33 Hydrography 37 Summary of winter fishery 46 Tagging studies 47 Discussion 56 Summary 58 Acknowledgments 59 Literature cited 59 Af^endix 61 iii THE FISHERY FOR SCUP WITH SPECIAL REFERENCE TO FLUCTUATIONS IN YIELD AND THEIR CAUSES by William C. Neville and Gerald B. Talbot ABSTRACT The catch of scup over the past 50 years has fluctuated widely. Data on this flshery for recent years (1922-35), obtained from State and Federal agencies, com- mercial fishery, and fishermen, have been analysed to determine causes of fluc- tuations. It was found that fluctuations in the summer fishery from New Jersey to Massachusetts were caused mainly by differences in the size of the successive year classes entering the fishery. Fluctuations in the catch of the winter trawl fishery off the Virginia Capes resulted from changes in the amount of cooling of the bottom water where these fish are found in winter. During cold-water conditions, the fish became more concentrated and were more easily caught; whereas, when the water was warmer, the fish scattered more widely and were not as readily available. Al- though fluctuations in catch of the summer and winter fishery have different causes, results of tagging and observations of size composition have disclosed that both fisheries draw on the same general stock. INTRODUCTION The shorefishes of the coastal waters of the Middle Atlantic and southern New England States undoubtedly facilitated the early coloni- zation of this region and subsequently have supported a fishing industry of major com- mercial and recreational importance. Among these fishes, the scup, Stenotomus chrysops' , has always been important, especially along the southern New England coast. Among the inshore species, it has usually ranked first both in quantity and in value since 1880, when the earliest catch statistics were collected. Along the coasts of New Jersey and New York, scup was relatively less important in the early years of the fishery, but of late (1929-33) tremendously increased catches have placed Note.— William C. Neville is now with the Columbia River Packers, Tokyo, Japan, and Gerald B. Talbot with the Tiburon Marine Laboratory, Bureau of Sport Fisheries and Wildlife, U^. Fish and Wildlife Serv- ice, Tiburon, Calif. 1 Listed as S. versicolor by some authors. it third in quantity and sixth in value among the food fishes of those States. The fluctuations in yield which have charac- terized the history of the species from Colonial days to the present have been at times the sub- ject of lively discussion as to their causes (Baird, 1873; Bigelow and Welsh, 1925). Lyman (1872) stated: Scup were abundant when the whites first visited the country, certainly in 1621 to 1642. At some time after this, not yet ascertained, they disappeared wholly, and, toward the end of the last century were not known in our waters. About 1794 they reappeared, and became abundant. In 1864 they decreased very much and are at the present scarce. ♦••*••• And now, in the midst of this theorizing and seeking for evidence, rises a phenomenon which puzzles both parties of the dispute. About the first of Juneofthisyear(1871) those trappers at Saugkonnet Point who had kept their netting down until that time, were astounded to find their traps clogged with myriads of "dollar-scup," little fish about the size of a Spanish doUar. They were tipped out of the bowls by hundreds of barrelsful. Fluctuations in the past have been attributed to: 1. Excessive catches or wasteful fishing by new types of gear. This opinion was usually advanced by operators of old types of gear in support of their opposition to the introduction of new methods of fishing. For example, the use of pound nets and floating traps was op- posed and condemned in Rhode Island and Massachusetts about 1870 (Baird, 1873) and purse seines in New Jersey beginning about 1920. Charges of destructive fishing against these gears resulted in restrictive legisla- tion (New Jersey Board of Fish and Game Commissioners, 1936). Later, summer fisher- men opposed a new winter fishery by otter trawls off the Virginia Capes (Pearson, 1932; Nesbit and Neville, 1935). 2. Occasional wholesale destruction of large numbers by predacious enemies, especially bluefish (Baird, 1873; Bigelow and Welsh, 1925). 3. Spasmodic changes in hydrographic con- ditions causing unusual movements of the fish and also mortalities of unusually large num- bers of scup by sudden cooling of the water (Baird, 1873). about 1845 and widely used by 1870) was guilty of destroying "many of the fertile (spawning) fish and preventing others from depositing their eggs" (Baird, 1873). The Massachusetts committee reported "no rea- sonable ground for complaint" (Baird, 1873). The Rhode Island committee on the other hand, concluded that the complaint was well founded and reported in favor of a very stringent law prohibiting the further use of traps and pound nets except within a limited district (Baird, 1873). The decisions of both these committees were based largely on the testimony of the fishermen. As a result of this difference in the reports of the two com- missions. Federal inquiry was made in 1871- 72. The Federal commission recommended "prohibition of use of nets from Friday night until Monday morning of each week of the spawning season, and after that no restriction need be imposed," (Baird, 1873). As far as is known, no action was taken on any of these recommendations, perhaps because shortly afterwards (1872) scup became very abundant (Southwick, Root, and Morton, 1893), lending support to those who contended that protection of the species by elimination or curtailment in numbers and amount of fishing of the "fixed apparatus" was not necessary to in- sure successful reproduction and continued good catches. 4. Annual variation in the relative success or failure of reproduction (Baird, 1873; South- wick, Root, and Morton, 1893; Nesbit and NeviUe, 1935). The effects of these fluctuations in the yield of scup on the livelihood of men engaged in fishing, especially in the coastal waters of southern New England, have been of such importance as to result in special State and Federal inquiries. From 1869 to 1870, the States of Rhode Island and Massachusetts each investigated the condition of the sea fisheries along the southern coast of New England (Baird, 1873). The reports of these commissions, however, resulted in much con- fusion because of the difference of the find- ings. At the time, the principal point at issue was whether or not the "fixed apparatus" (pound nets and floating traps introduced To the present, however, opinions of those interested in the fisheries continue to differ on the causes of changes in yield and the measures necessary to make possible the best utilization of the supply. Failure to reach satisfactory agreements on these con- troversial problems has in the past been due, in part at least, to the lack of infor- mation on the real causes of changes in abundance and the technical difficulty of correcting wasteful and destructive prac- tices. It was fortunate, therefore, that in 1927, Bureau of Fisheries appropriations were made available to begin a scientific study of the shorefishes of the Middle Atiantic region for the purpose of obtaining reliable information as a basis for the wise conservation of the principal species. The study of scup has been a part of this general investigation that be- gan with a study of the summer inshore commercial fisheries of the Middle Atlantic and southern New England States and was subsequently extended to the summer fisheries of Virginia and also to the winter fishery offshore of the Virginia Capes. The following report comprises a description of the scup fishery, information on the life history, migra- tions, and causes of fluctuations in yield with recommendations for the conservation along the Atlantic coast. RANGE Scup (fig. 1) ranges along the eastern coast of the United States from South Carolina to Maine (Holbrook, 1855; Bigelow and Welsh, 1925). South of New York scup is commonly known as "porgy", and along the southern part of New England, as "scup". Baird (1873) remarks as follows about the vernacular name of the scup: Steindachner as follows: and Agasslz (1872) comment In 1621, Massasoit entertained his half-famished Puritan visitors with "two fishes, like bream, but three times so big and better meat." This was on the shore of Buzzard's Bay, and the fishes can have been nothing else than scup .... The Englishmen doubtless meant what is still called in Europe the "common sea-bream" whose outline is much like that of our scup. Common names: porgy; porgee; scup; scuppaug; mischup. The species has a lesser variety of names than most others belonging to our coast; . . . it is the familiar scup of scuppaug, from mish-cup-pauog of the Nar- ragansett Indians. In the time of Roger Williams its English appellation was bream, from the resemblance to the British fish of that name. Its greatest commercial importance is in the summer fishery from New Jersey to the southern shores of Cape Cod, Mass., and in a winter fishery from off Cape Hatteras, N.C. (lat. 35° 10' N.) to the offing of Cape May, N.J. (lat. 39° N.). Figure 1.— Scup In earlier times scup were caught In the greatest quantities In southern New England, especially In Rhode Island. Recently the species has become increasingly important in the southern part of its range. This has resulted principally from a remarkable rise in the summer fishery catch of New Jersey in 1929. This increase has been sustained to the present (1935). A further development in recent years has been the discovery of scup in sufficient concentration in the winter to support an increasingly important fishery (Pearson, 1932), Although for many years there had been much speculation about the winter habitat of the species (Lyman, 1872; Blgelow and Welsh, 1925), it was not undl the winter of 1928 that large quantities of scup were lo- cated in the general offshore region from the offing of Cape Hatteras, N.C., northward to the offing of Cape May, N.J. In addition to their Importance in the com- mercial summer fishery, scup have contributed much to the catch of the large and increasing numbers of anglers from New Jersey to southern Massachusetts. DESCRIPTION OF THE FISHERIES The existence of distinct summer and winter fisheries for scup along the Atlantic coast is a natural consequence of seasonal changes in water temperatures. Both fish- eries occur within the Middle Atlantic Bight, or that part of the Atlantic Ocean within the 100-fathom curve extending from Cape Hatteras to Cape Cod (fig. 2). This region of the Continental Slope is inhabited by populations of fish including scup, whose movements are affected by changes in water temperatures. The most significant move- ments are the migrations of fish to and from the inshore coastal waters in the spring and autumn. Those migrations occur simultaneously with seasonal changes in water temperature throughout this region. In the winter, the inshore waters out to about 20 fathoms are too cool (2° to 3° C.) to be tolerated by most of the shore- fishes which at this time of the year are in offshore and warmer regions (6° to 12° C). At that time, the fishery is centered from Cape Hatteras to the offing of Cape May where large quantities of scup, sea bass, and fluke are caught. Vernal warm- ing commences by early March, and sur- face temperatures usually reach a maxi- mum throughout the area from Cape Hatteras to Cape Cod early in August. At this time, the higher temperatures are usually inshore. With this warming, the shore species migrate from their winter habitat to inshore waters. During the spring and summer and as late as November, the fishery for scup is in the inshore waters,, principally from Cape May to Rhode Island. Autumnal cooling begins by October, and the lowest temperatures are reached in March. With the decline in tempera- tures in the autumn, scup begin their mi- gration to offshore and southern winter regions. The summer fishery for scup is princi- pally by pound nets, floating traps, otter trawls, purse seines, and handlines. The winter fishery is exclusively by otter trawls. POUND NETS Pound nets were first introduced on the Atlantic coast about 1850 in Rhode Island, and were in general use by 1873 from New Jersey to southern Massachusetts (True, 1887). Figure 2.— Principal scup fishing areas during the early 1930's. This fishery continued to expand particularly along the New Jersey shore, where, at the present time, the majority of the scup catch by pound nets is made (table I). The general construction of the pound net has not changed much since its introduction, the improvements being concerned more with the convenience of operation such as the use of power in raising nets and brailing of fish, and in the "run" boats used to transport the crew, gear, and catch. The pound net is a stationary gear, and hence its catch is limited to fish that enter the net. It can be operated only in relatively close inshore waters out to a depth of about 60 feet. Operation is limited from April to December, when migratory fish are avail- able in inshore waters. In 1933, the pound net catch was about 47 percent of the total catch of scup by all gear (table 2). FLOATING TRAPS The floating trap fishery for scup is con- fined principally to the inshore waters of the coast of Rhode Island, although a few traps are set off Amagansett, Long Island, N.Y., and on Five Fathom Bank, off New Jersey (fig. 2). The principal difference between the pound net and floating trap is that the latter, as the name implies, is buoyed by large floats (drums or hogsheads) and is anchored; whereas, the former is held in position by means of stakes or poles. The floating trap is especially adapted to regions of deep water, hard bottom, and strong tides; and since these conditions prevail along the shore of Rhode Island, traps have become the principal gear of that State's shore fishery. For a detailed description of floating traps and methods of fishing, see the account by Southwick (Baird, 1873). The floating trap was first used off Rhode Island about 1850 (Lyman, 1872) and was in Table 1. — Catch of scup landed in New Jersey by different types of gear^, 1889-1933 (not consecutive) [In pounds] Years Pound Seines Otter trawls Hand- lines Gill nets Fyke nets Total nets Haul Purse 1889 2 12,000 1890 8,720 6,500 - - - - 1,000 16, 220 1891 12, 982 10,600 . - - - 2,100 25,682 1892 36,900 10,850 - , - - - 400 48,150 1897 551, 100 3,800 - - 202,550 - - 757,450 1898 339,150 300 - - 281,415 300 1,000 622,165 1901 385,854 3 80,110 - - 140,075 900 160 607,099 1904 702,482 3 180,000 - - 172,200 - - 1,054,682 1908 324,000 3 583,000 - - 286,000 500 3,000 1,196,500 1915* 1,226,343 - - - - - - 3,279,693 1917* 1,604,393 - - - - - - 3,673,173 1921 1,558,670 - 2,345,000 - 210,792 1,000 - 4,115,562 1926 531,343 - 1,652,400 23,311 244,425 600 - 2,452,079 1929 2,423,024 400 3,833,200 5 1,485,400 85,807 5,767 - 7,853,598 1930 2,733,907 - 3,343,693 5 1,412,081 71,010 3,350 - 7,564,041 1931 3,905,869 - 1,255,531 5 2,341,430 24,040 - - 7,526,870 1932 3,482,395 _ 1,4^0,920 ' 1,484,250 28,301 231 - 6,436,097 1933 3,708,969 - 407,241 5 731,349 31,458 2,292 55 4,881,364 ^ U. S. Bureau of Fisheries (U. S. Cammlssion of Fish and Fisheries) statistical canvasses with the exception of 1908 when canvass was made by the U. S. Bureau of the Census. ^ Catch by gear not available. ■^ Possibly includes some catch by purse seines. * Catch by gear other than pound nets not available. ' Includes catch by New Jersey vessels engaged in winter trawl fishing off the Virginia Capes. Table 2. --Catch of scup landed in 1933^ by States and gear^ [In pounds] states Pound nets Floating traps Seine Otter^ trawl Hand- lines Gill nets Fyke nets Total Haul Purse New Jersey New York 3,708,969 1,020,187 123,578 118,932 1,878,853 600 407,241 731,349 432,766 17,000 1,788,178 31,458 24,600 226,300 2,922 55 4,881,364 1,478,153 Rhode Island Massachusetts .... 2,019,431 2,133,410 Total Percent of total. 4,971,666 47.29 1,878,853 17.87 600 .01 407,241 3.87 2,969,293 28.25 282,358 2.69 2,292 .02 55 10,512,358 100.0 ■"■ Latest available complete statistics. ^ Report, Fishery Industries of the United States, 1934. ■' Includes catch of vessels registered in each respective State but engaged in the winter trawl fishery off the Virginia Capes. * Ijsss than .01 percent. general use by 1873, especially in spring fishing for scup. Traps are still operated there almost exclusively for scup. This is probably because scup are available there in large quantities only during 2 months of the year (end of April to end of June) when they ap- proach the Rhode Island shore on their annual spring migration to inshore waters. During this period, large quantities in excess of de- mand are caught. This glut has led the Rhode Island trap operators to hold the excess amounts of scup alive in "pounds" (explained later), which are anchored in some sheltered cove and from which shipments are made throughout the summer. With the termination of the main spawning about the end of June (Bigelow and Welsh, 1925), scup do not trap readily and the catch declines sharply; consequently, these "spring scup traps" are usually dismantled in early summer and put ashore until next spring. U.S. War Department regulations permit fish- ing in this region only from April 25 to July 25. The restriction after the latter date apparently does not greatly interfere with the scup fishery, since it is probable that the traps would not be operated after that date even if permitted, because the main bodies of market-sized scup usually either disperse from this area after June or at least do not trap readily. Like the pound nets, the floating traps have not under- gone much change in construction, the im- provements being confined to easier and quicker operation by the use of power. The majority of the traps have been set on the same locations since the beginning of the fishery about 1850. The catch of scup by floating traps in Rhode Island comprises the bulk of the total catch of all gear for that State and is rela- tively important in the general fishery for scup, representing approximately 18 per- cent of the total catch of the species by all commercial gear in the fishery from New Jersey to Massachusetts (table 2). PURSE SEINES The purse seine fishery for scup is carried on principally by New Jersey vessels fishing from Cape May, N.J., southward to Parramore Banks, Va., and, being mobile, has access to a large area of fishing ground, the extent of which is limited only by State regulations. New Jersey (New Jersey Board of Fish and Game Commissioners, 1936) prohibits the use of seines and trawls from taking or at- tempting to take fish of any kind from waters within the jurisdiction of the State, including waters of the Atlantic Ocean within 3 nautical miles of the coastline, without a license. A license allows fish to be taken in waiers of the Atlantic Ocean within jurisdiction of the State, but at a distance of not less than 2 miles from the coast. Virginia (1936) also prohibits the use of purse seines and otter trawls except under special conditions in certain territorial waters of the State. New York (New York Conservation Department, 1936) regulations affect the catches of purse seine and otter trawlers to a lesser extent, because restriction applies only to certain small areas relatively unimportant as com- mercial fishing grounds. In contrast to proud nets and floating traps, the purse seine fishery for scup is a com- paratively recent development. Although the purse seine has long been in use as an ef- fective apparatus for catching schooling fish, it was not until about 1920 that this gear came into prominence in the scup fishery. Its use resulted mainly from the development about that time of motorized boats capable of making quick trips to and from distant fishing loca- tions. Thus, fishermen were able to operate offshore in seasons when the market value of fish was high. Because the southern New Jersey ports offer good harbors and are con- venient both to the offshore fishing grounds and to good markets, they became a center for the purse seine fishery. From these New Jersey ports, purse seiners fish throughout the summer for shore species, which are most readily available or have the highest market value. From 1930 to 1935, purse seines have pro- duced a relatively small part of the total yield of scup along the Atlantic coast (table 2). During recent years the reported landings of this species have been much less than the actual catches, because quantities of fish have been discarded at sea. This discarding often occurs during periods of unusual abundance that have prevailed along the New Jersey coast in recent years. Furthermore, landing reports do not always include the total possible catch, since fishermen may pass up schools of scup in search for more profitable species. In the New Jersey summer fishery for scup, however, the purse seine catch is relatively important, being exceeded only by that of pound nets (tables 1 and 2). OTTER TRAWLS The otter trawl fishery for scup is the only year-round fishery for this species because this gear is effective in the winter when other gear fails to catch this fish. The catch by otter trawls in recent years accounts for approxi- mately 28 percent of the total yield (table 2). The relative importance of this gear is a recent development, for prior to 1929 the catch by otter trawls was insignificant and was confined to the summer season. With the development of a winter trawl fish- ery about 1929 and its rapid expansion in later years, the catch increased greatly. The winter and summer trawl fisheries, however, are not only markedly different in the amount of catch, but also in locality of fishery, size of fleet, and kinds of fish caught in addition to scup. The summer otter trawl fishery for scup is conducted principally by New Jersey ves- sels operating in inshore waters (about 5 to 40 fathoms) off Cape May, N.J., and Cape Henlopen, Del. Its development began about 1926, a natural outgrowth from flounder "dragging". In the winter in inshore waters, small boats "dragged" (and still do) for winter flounders {Pseudopleuronectes americanus, Wal- baum) and in the summer, for fluke (Paralichtys dentatus, Linnaeus). In recent sum- mers (1935-36), fishermen using small otter trawl along the inshore waters (out to 20 fath- oms) of Fire Island, N.Y., have turned more toward the catching of scup. This diversion resulted from a scarcity of fluke and the knowledge that scup can be caught by the so-called "balloon net" as distinguished from the so-called "flat net" commonly used for fluke. The efficiency of the balloon net in catching scup has been demonstrated by the success of the southern winter trawl fishery, which uses the net almost exclusively for such species as scup and sea bass. It is probable that the summer oner trawl fishery for scup wiU increase in coming years in other parts of the range of the species. At the beginning, the fleet consisted of comparatively small powered boats (25-50 feet) that, because of their size, were re- stricted to fishing close to shore (not beyond 15-25 miles). As the fishery developed, larger and more powerful boats were added to the fleet. Many of these were diesel-powered, capable of fishing farther offshore and of taking large catches on trips of long duration. This summer fleet fished mainly for fluke, so that the occasional good catches of scup were only incidental. Hence, prior to 1929, the summer catch of otter trawls contributed relatively little to the total catch of scup of the Atlantic States (fig. 3). Since 1929, the summer trawl catch of scup has increased mainly because of improved fishing methods and also, as will be shown later, because of increased abundance along the New Jersey coast. The activity of this fleet is still directed primarily for fluke, which has a higher market value than scup. Hence, the present summer catch of scup by otter trawls is still rela- tively small. Although complete records are not available, it is estimated that this summer trawl fishery in 1933 accounted for only 27 percent of the total yield by this gear (summer and winter) from New Jersey to Massachu- setts and only approximately 8 percent of the total catch by all gear for New Jersey alone. The winter trawl fishery for scup is con- fined principally to the general offshore regions in depths from 20 to 100 fathoms from the offing of Cape May, N.J., to Cape Hatteras, N.C. (fig. 2). The development of this fishery is one of the most important features in the history of the industry, principally because it has resulted in the discovery of commercial quantities of scup (as well as fluke, sea bass, and croakers) in a winter habitat, the location of which for years was the subject of much speculation (Baird, 1873; Bigelow and Welsh, 1925). Because of increasing activity and amount of catch, this new branch of the indus- try has added much to economic and conserva- tion problems (Pearson, 1932; Ncsbit and Neville. 1935). The development of this fishery. Like that of the summer trawl fishery, was an out- growth of flounder dragging (Pearson, 1932). About 1920 New Jersey "fluke draggers" were first attracted to the more inshore and southern part of the winter fishery region, especially along the Virginia and North Caro- lina coasts in their search for fluke and croakers. The New Jersey boats went south in the spring to intercept the schools of fish migrating to inshore areas and in the autumn followed the fish south from New Jersey waters when the species began their return migration to more southern regions. The fleet at that time consisted mainly of small, low-powered boats that formed the summer dragger fleet of southern New Jersey. The vessels became so numerous that Virginia and North Carolina, seeking to protect their extensive inshore pound net and haul seine fisheries, passed laws in 1926 and 1930 pro- hibiting all trawling in State-controlled waters Including the lower Chesapeake Bay. The Virginia law was changed in 1936 to provide that no trawling should be done in any territorial waters of the State, except from a point about 10 miles south of Cape Henry Lighthouse to the North Carolina State line during the months of February, March, April, and May of any year and only then by holders of a license for which a fee of $25 is required. Only residents of Virginia are eligible to receive these licenses (Virginia, 1936). Perhaps as a result of this, the larger and more powerfully equipped vessels grad- ually ventured offshore and finally located commercial quantities of such typical summer fish as scup, sea bass, and fluke in the deeper water 30 to 50 miles off the Virginia coast. This rather startling discovery of at least part of the winter habitat of summer fishes led to the establishment of a new fishery. In the winter of 1928-29, several New England vessels equipped for dragging in the deeper water went south and fished regu- larly in the offshore region. They were so successful that in the following winter they were joined by other vessels. As a result, each winter has seen an increasing number UlLUtWBOF POUNDS ] u oU ,— Hi, , — MASSACHUSETTS m. I POUK) NETS AND TKAPS I SEMES I OTTER THAIWLS D ALL OTHER GEAR S' 7 e- bi 4- 3- 2' f I RHODE ISLAND iM MLLIONS OF POUNDS 3 1030-31 1323313445 3t3Z 3^4 WINTER TRAWL HSHERY VA. LANDINGS ONLY MILLIONS OF POUNDS NEW JERSE Y NEW JERSEY STATE RECORDS Figure 3.- -Catch of scup in pounds landed by States and gear. 10 of boats, and by the winter of 1935, over 100 vessels were engaged in this new fishery (Nesbit and Neville, 1935). The present fleet has largely high-powered, sturdy vessels equipped for fishing any part of the region from Cape Hatteras to Cape Cod and in depths out to about 80 fathoms. Most of the winter trawlers land their catches at Virginia ports, namely: Norfolk, Phoebus, and Portsmouth. A smaller part of the fleet lands its fares at Cape May and Wildwood, N.J.; and in the more recent winters, an in- creasing number at New York, N.Y. The landings of this winter fishery have increased so rapidly since its inception in 1929 that the catch now amounts to approxi- mately 73 percent of the total yield of scup by otter trawls from New Jersey to Massa- chusetts and approximately 20 percent of the catch by all gear. HANDLINES Commercial and sport handline fishing for scup is carried on along various sections of the coast. An important commercial fish- ery is centered at Wildwood, N.J., where a fleet of small boats fishes, in addition to scup, for squeteague, sea bass, and bluefish. Some fishing is also done in the vicinity of Montauk, N.Y., and Woods Hole, Mass., prin- cipally for scup, sea bass, and fluke. The best handline fishing is usually in August, September, and October, after the main spawn- ing season is over, since scup do not take the hook readily during the spawning season. The catch by commercial handliners was an important part of the total yield of all gear in early days, but in late years, with the development of more efficient methods of fishing, the handline catch has diminished to insignificant proportions compared to other forms of gear. In recent years, salt-water angling has markedly increased, especially along the shores of New York and New Jersey. Although complete records of catch by anglers are not available, it is believed, on the basis of a few reports, that this catch must amount to surprisingly large quantities of fish and in some localities even exceeds the catch by the local commercial gear. It was not possible to cover this sport fishery in this study. Catch records of both the commercial hand- liner and angling fisheries have been omitted from further discussion, because the data are incomplete and otherwise unsuitable for explaining changes in yield. FLUCTUATIONS IN YIELD AND THEIR CAUSES In the following discussion of the fluctua- tions in yield of scup, tht summer fishery will be treated separately from the winter fishery because of the differences in the kind of gear, the locality of the catch, and the quantity of catch. Also, there is the possibility, indicated by results of tagging experiments, that certain parts of the sum- mer fishery draw on separate population units, which are available to the winter fish- ery because of migrations to a common winter habitat. In addition, it is desirable to divide the summer fishery into a New Jersey fishery and a New York-southern New England fishery because the fisheries in these two localities also differ in the type of gear used, the length of season, the quantity, size, and age composition of the catch, and also because of the possibility that each fishery draws on separate population units. Total annual landings of scup were deter- mined for various years between 1879 and 1933, as a result of periodic canvasses by 11 the Bureau of Fisheries and of annual pound net catch statistics by the States. The States were often surveyed in dif- ferent years so that the catches in each State are not always available every year. For this reason the changes in total yield of each State will be discussed sep- arately. SUMMER FISHERY Statistics of the Fishery, New Jersey Changes in total yield. — It is evident chat the total yield has undergone major fluctuations (table 1). The data do not, how- ever, reveal reliable information on the changes in gear, either as to amount or type; and since these often are a principal cause of changes in catch, the lack of accurate records of gear injects some doubt and dif- ficulty in interpreting the changes in yield in terms of changes in abundance. In addition, the records of catch are subject to some in- accuracy because many of the data, espe- cially in the earlier years of the Bureau's canvasses, were obtained from operators who lacked written records and based their fig- ures on memory. Nevertheless, it is believed that the Bureau's statistics, though not reveal- ing the absolute values of the changes in the yield, are sufficiently reliable to reveal major changes that have occurred. The catch of scup in New Jersey by the three principal types of gear (pound nets, otter trawls, purse seines) was small from 1890 to 1892. It increased beginning in 1897, reached a peak in 1929, and remained high to 1933. From 1890 to about 1908, the fishery expanded, mainly by increases in numbers of ocean pound nets, especially in the southern and later in the central seaboard counties of the State. Since 1908, the number of these nets has remained about the same although there have been minor changes from year to year. Other changes in gear resulting in an increase in the catch were the expansion of the purse seine fishery about 1920 and the otter trawl fishery (especially in the winter) beginning in 1929. Measurement of fluctuations. ■In the present study, the pound net fishery in New Jersey has been chosen for an analysis of changes in abundance because it produces the most important part of the total yield of scup and provides a convenient unit for measuring the relative abundance and availability of the fish. There were certain factors that made it difficult to obtain from these pound net records a clear understanding of the causes of fluctuations in the yield. These included changes in availability by erratic movements of fish, the lack of accurate and complete records of the quantities of small fish dis- carded at sea in times of unusual abundance and low market, and changes in fishing effort through destruction of gear or curtailment of fishing during storms. Few operators kept written accounts of the storm periods and of the number of nets destroyed or damaged. Changes in the amount of fishing also occurred when fouled nets were changed at different times of the season by being removed com- pletely from the water, or, as in some dis- tricts, by being hung on the pound- poles to dry for a few days. Few records contained notations of the actual number of nets fishing during such periods of drying or changing gear. Despite these influencing factors, a unit of measure termed the catch per trap per season was computed. This unit represents the num- ber of pounds of scup caught by an average trap in one season. In the analysis of the causes of changes in the catch of the stationary gear, the term "trap" will be used to refer to both pound nets and floating traps, because both gears are fundamentally the same in construction and operation, and changes in their catches are affected by the same or similar causes. The measure was fairly indicative of changes in abundance or in availability and could be used for showing relative changes in yield of the pound net fishery of New Jersey. This gear produced most of the catch in the State; therefore, its catch reflected the major changes in total yield. 12 In the study of changes in the catch per trap per season, data were available from two sources: (1) Annual reports of the New Jersey Board of Fish and Game Commissioners, showing the gross catch of each species and the average number of nets fished during the season; and (2) operators' private records of daily catch and number of nets fished. The catch per trap was used instead of catch per lift because the State records on which we depended for earlier years recorded only the number of nets fished and had no record of number of lifts (table 3). All the nets in operation were not always lifted the same day, so that the catch per lift may or may not have represented one or more days' fishing; further, a net fishing 2 days for instance without being lifted the first day did not necessarily catch twice as much as a net lifted after only 1 day's fishing. The analysis of changes on the basis of catch per trap is limited to the period 1922-35 inclusive, because detailed records for earlier years are not available. From a relatively high yield in 1925, the catch per trap declined to a low level in 1928 but recovered quickly to a record high in 1929 with continued high yields until 1935. Since these changes were measured by the same unit yardstick for all years, the fluctuations in catch were, there- fore, the result not of any increase in nets but of either changes in availability or abun- dance, or a combination of both. Admittedly, Table 3. — Catch of scup in New Jersey pound nets and average catch per net, 1922-35^ Years Total catch Nets (traps) Catch per net Pounds Number Pounds 1922 1,601,244 149 10,747 1923 1,284,489 135 9,515 192*; 1,295,441 130 9,965 1925 1,404,680 119 11,804 1926 543,242 126 4,511 1927 545,365 113 4,809 1928 316,654 106 2,987 1929 2,400,043 116 20,630 1930 2,467,206 104 23,723 1931 3,905,869 128 30,515 1932 3,689,127 118 31,264 1933 3,539,041 102 34,696 193 70 104 25 65 165 261 112 126 155 26.0 86 129 113 11 29 92 5 65 68 18 62 169 264 90 129 167 26.5 86 133 123 25 78 3 45 75 14 57 138 246 101 131 204 27.0 93 U5 123 J 24 69 7 32 70 16 49 132 206 81 111 175 27.5 90 U2 U'J 6 15 61 4 34 53 7 40 94 144 79 92 172 28.0 97 175 167 10 11 60 2 27 30 9 35 67 129 55 66 119 28.5 106 129 147 12 11 53 4 22 39 5 27 68 103 66 54 120 29.0 85 198 150 (. h 42 /, 21 27 9 27 43 91 32 53 80 29.5 61 167 111 t\ A 2 'J 3 14 29 2 21 41 80 35 32 77 30.0 66 167 lie 1 7 29 . 13 24 7 21 35 72 22 36 59 30.5 52 180 78 ,, 2? _ 14 32 t 19 35 64 27 17 52 31.0 42 166 99 « 21 4 12 23 1 21 32 58 18 13 47 31.5 48 161 65 _ 11 8 2 12 24 7 17 30 83 24 24 52 32.0 49 129 52 1 4 6 9 24 3 13 25 71 11 17 36 32.5 45 118 48 2 2 7 _ 5 10 4 8 23 42 13 24 40 33.0 30 127 28 _ 2 4 2 4 10 - 16 19 51 10 10 20 33.5 25 121 17 1 ) 7 7 i t 13 39 15 9 23 34.0 17 117 24 _ 1 - 2 1 2 4 7 25 7 15 13 34.5 24 64 13 1 i 1 6 - 4 11 21. 6 6 11 35.0 10 64 H _ _ 3 1 - 4 5 1 J 9 5 6 8 35.5 11 42 7 _ 1 _ 4 1 2 3 7 19 6 3 6 36.0 2 31 6 . 2 . 1 - 2 2 - 4 6 - 3 8 36.5 3 32 1 . - 1 2 - 3 2 4 - 1 2 37.0 3 19 6 , - - - 1 - 2 2 5 5 2 1 37.5 2 22 _ - - - - - - 4 4 2 - . 38.0 _ 16 2 - - 1 - 1 - 1 1 4 1 1 2 38.5 _ 16 3 - - - - - - ) 2 J 1 - - 39.0 - 12 - - - - - - - - - 1 - - - 2 39.5 _ 20 1 - - - - - 1 - - - - 1 40.0 _ 3 _ - - - - - - - 1 1 1 - - 40.5 - 5 1 - - - - - - - 41.0 . 7 . - - - - ~ - - - - - - ~ 41.5 _ 4 - - - - - - - - - - 1 - 1 - 42.0 - 10 - - - - - - - - - - 2 - - 42.5 - 2 - - - - - - - - - - ' - 43.0 . 3 - - - - - - - - - - - - - ■ 43.5 _ 5 - - - - - - - ' - - - - - 44.0 _ 2 - - - - - - - - - - - - - 44.5 - t - - - - - - - - - - ■ 45.0 . 2 - - - - - - - - - - - ~ 45.5 - 1 _ - -- - - - - - - - " - ' - 46.0 - 2 - - - - - - ' - - - " 47.0 - 3 - . - - - - - - - - - - - - 48.5 - 1 - - - - - - - - - ■ " ' ' ~ Total 2,143 4,066 2,557 398 1,639 2,502 292 2,113 3,900 603 2,364 4,842 5,884 5,312 5,727 5,433 ' Sanples rrom catches sorted at oea into size categories converted statletlcally to equivalent of random samples, base 100 riah, of unsorted catches. ' To March 15. Summer data were not available for com- paring the winter catch of 1934 with the summer catch of 1933, but comparison of size composition of the catches in the winter of 1934 can be made with that of the preceding winter. In 1934 the composition of the landed catches again changed markedly, for com- pared with 1933 relatively more medium and large fish were present. The medium sizes were mostly of the 1931 brood that had been prominent as small fish in the preceding winter. This change could be ex- pected because similar progression of broods into the larger market categories with increase 35 in age and growth had been observed in the summer fishery (fig. 6). The increase in numbers of large fish (25 cm. and more, 1930 year class and older) was greater than was expected on the basis of their relative importance in the preceding winter. Small-sized fish were very numerous, how- ever, in 1934, for considerable quantities both of undersized and of legal-sized fish were reported discarded at sea because no market existed. From fishermen's estimates of size and from a few samples of measure- ments obtained at sea, it was learned that these discards were mostly of the 1932 brood, supplemented by lesser numbers of the 1933 brood. It was estimated that of a total catch of approximately 2.4 million pounds of scup made by vessels landing at Virginia ports in January, February, and March of 1934, more than 500,000 pounds, or 20 percent, were discarded at sea. Expressed in num- bers of fish, of a total catch of approxi- mately 4.7 million scup, about 1.9 million fish, or 40 percent, were destroyed and discarded. Because of lack of observations in New York and New Jersey, it was not possible to estimate reliably the number of small fish discarded from the catches landed at these ports, but since small fish are less acceptable in these markets than In Virginia, it is probable that the proportions were even higher. In the winter of 1935, the age and length composition of the landed catches was similar to that of 1934. The 1932 year class, which accounted for most of the scup discarded in 1934, figured prominently in the catch of 1935 under the market cull of "small", and the 1931 year class moved into the "medium" market category after being present in the preceding winter (1935) as "small" (fig. 8). The most striking difference between the 1934 and 1935 catch was the relatively small quantity of the smaller sizes of scup reported discarded during winter 1935. In that winter, most of the discarded fish of this size group were presumably the 1933 brood. Hence, the lack of reports of any considerable discarding indicated that the 1933 year class was actually less numerous than the 1932 year class in that area at that time. The magnitude of these shifts in the size composition of the catches in each of the past several winters is shown more strikingly on the basis of length data weighted to make them proportional to the number of fish landed in total catch and to catch per day (fig. 8, tables 18 and 19). They revealed that the total catch in number of fish increased steadily from 1931 to 1935. Much of this increase was due to increasing fishing ef- fort by a larger fleet. The shifts of fish from larger sizes in 1931 to smaller sizes in 1932 and from smaller sizes in 1933 to larger sizes in 1934 and 1935 are also obvi- ous from figure 8. These sharp changes in size composition were reflected in the catch per day's fishing. For example, when the size composition of scup catches shifted from large sizes in 1931 to smaller sizes in 1932, the catch per day's fishing also dropped from 6,240 pounds in 1931 to 2,643 pounds in 1932 (fig. 9, table 16). Similarly, in 1933 when the small sizes continued to be relatively more important than the larger sizes, the catch per day's fishing remained low and even dropped to 1,336 pounds. In 1934 when the number of medium fish increased compared to 1933, the catch per day increased to 4,008 pounds. In 1934, however, as previously described, the small sizes were exceptionally numerous and, for the most part, discarded. If they had been retained as part of the landed catch, the catch per day's fishing would undoubtedly have been much higher. In 1935, although small fish (about 17.5 cm.) were relatively less numerous than in 1934, the number of large fish was relatively more numerous, the latter undoubtedly helped materially in preventing the catch from declining to a much lower point than 2,846 pounds per day. From the foregoing discussion, it appears that the yield of the winter fishery in the short period of five winters (1931-35 inclusive) has fluctuated sharply as evidenced by erratic changes in catch per day's fishing and by marked differences in size composition of the catch. If the principal cause of changes 36 Table 18. — Length of scup in the catch of the winter trawl fishery landed at Virginia ports, 1931-35, weighted according to the quantities landed [Numbers of fish, in thousands] Length 1931 1932 1933 1934 1935 Length 1931 1932 1933 1934 1935 Cm. Cm. 17.0^ 17 130 115 82 20 31.5 47 23 15 35 34 17.5 24 245 161 73 36 32.0 40 38 9 28 22 18.0 32 353 215 63 39 32.5 36 3 8 20 26 18.5 23 360 209 65 60 33.0 30 16 3 24 12 19.0 20 255 161 53 103 33.5 25 15 6 16 15 19.5 18 155 137 79 217 34.0 24 - 4 10 11 20.0 19 98 68 117 382 34.5 17 7 1 9 8 20.5 22 94 64 192 518 35.0 12 8 6 2 5 21.0 19 86 58 290 443 35.5 9 - 4 7 5 21.5 27 156 80 278 405 36.0 5 7 3 2 4 22.0 27 262 73 282 259 36.5 5 - - 3 - 22.5 26 193 95 194 257 37.0 4 - 3 2 2 23.0 30 212 72 144 269 37.5 3 - - 2 - 23.5 38 133 86 112 293 38.0 3 7 - 2 - 2-^.0 45 133 75 100 248 38.5 3 - - - - 24.5 47 122 76 108 161 39.0 2 - - - - 25.0 59 111 75 120 135 39.5 3 - - - - 25.5 68 120 72 131 1?3 40.0 1 - - - " 26.0 62 73 56 134 126 40.5 1 - - - - 26.5 64 54 53 117 144 41.0 1 - - - — 27.0 66 86 45 103 124 41.5 1 - - - " 27.5 64 50 24 72 116 42.0 2 - - - - 28.0 81 31 24 62 81 43.0 1 - - - - 28.5 74 46 17 52 76 43.5 1 - - - — 29.0 79 37 21 44 57 44.5 1 - - - - 29.5 61 64 27 8 11 15 38 34 48 40 47.0 1 - - — ■ 30.0 30.5 53 5 17 30 31 Total 1,560 3,801 2,244 3,360 4,983 31.0 53 42 7 29 28 •"• Fish helow 17.0 cm. (approximately) were discarded by dealers as unsaleable. in yield were changes in abundance, it would be expected that the changes in size com- position would involve principally changes in the relative importance of the annual increments of young fish as was the case in the summer fishery. The best catches of the winter fishery, however, were in years when the large fish were relatively more important (1931, 1934, 1935, figure 9); and further, that the relative importance of the several size groups that composed the catch not only differed when one winter was com- pared to another, but underwent erratic changes even within a season. The latter, in particular, suggests that fluctuations in the catch re- sulted from changes in availability rather than changes in abundance. Hydrography The principal causes of the changes in availability of scup in the winter fishery may be found in the hydrographic studies of the winter trawl fishing area. It is not surprising to expect that differences in water temperature should affect the movements and behavior of fish in the winter trawl fishery, since their seasonal migrations appear to be closely related to temperature changes. With the chilling of the inshore waters in fall, the fish leave their summer grounds and migrate to winter regions where temperatures are about as high as the lowest found in the summer fishing grounds along the inshore coastal waters. Likewise, with the warming 37 Table 19.— Length of scup in the catch of the winter trawl fishery landed at Virginia ports, weighted according to the quantities landed on catch per day's fishing per trip basis, 1931-35 [Numbers of fish] Length 1931 1932 1933 1934 1935 Length 1931 1932 1933 1934 1935 Cm. ^ 17.0 17.5 18.0 18.5 19.0 65 92 121 90 73 91 167 233 230 158 122 171 232 226 174 90 80 69 72 60 12 22 23 36 62 Cm. 31.5 32.0 32.5 33.0 33.5 166 144 130 103 83 16 27 2 12 11 17 10 9 3 7 38 32 22 27 18 20 13 15 7 9 19.5 20.0 20.5 67 71 83 95 60 62 198 73 70 88 130 214 129 226 304 34.0 34.5 35.0 79 57 40 5 6 4 1 7 11 10 2 8 6 4 3 3 21.0 74 53 63 323 260 35.5 29 - 4 21.5 102 100 87 309 236 36.0 15 5 4 2 2 22.0 101 168 79 315 152 36.5 13 - — 2 1 22.5 100 118 104 216 150 37.0 13 - 4 4 23.0 119 135 78 160 158 37.5 8 - ■" 2 "" 23.5 152 83 93 124 172 38.0 7 5 — 2 ~ 24.0 171 86 80 111 146 38.5 7 - - ~ ~ 24.5 185 80 82 121 95 39.0 3 - ~ " " 25.0 227 73 82 133 79 39.5 7 - - — "■ 25.5 258 78 79 146 72 40.0 1 - - ~ ~ 26.0 239 47 61 150 73 40.5 1 - - ~ " 26.5 242 33 58 131 84 41.0 3 - - " ~ 27.0 248 57 49 114 72 41.5 1 - - - ~ 27.5 239 33 26 80 68 42.0 3 - - - ~ 28.0 301 20 27 68 48 43.0 1 - - - ~ 28.5 283 30 18 58 45 43.5 1 - - - ~ 29.0 289 25 22 49 33 44.5 3 - - - - 29.5 221 19 11 43 28 47.0 1 - - - ~ 30.0 272 4 17 38 23 30.5 191 2 19 35 18 31.0 187 24 7 32 16 Total 5,782 2,453 2,478 3,739 2,925 Fish below 17.0 cm. (approximately) discarded by dealers as unsaleable. of the coastal waters in spring, fish make a return migration from the winter habitat to the inshore summer fishing grounds. The study of hydrographic conditions is based principally on serial water temperatures collected by the Bureau's vessel Albatross II in the winters of 1929-32, by the Woods Hole Oceanographic Institution research vessel Atlantis in the winters of 1933 and 1934, and by surface and bottom water temperatures collected through the voluntary cooperation of various fishing captains in the winters 1933- 35, inclusive. On the fishing vessels, observa- tions were limited to bottom and surface only. Since scup as well as sea bass and fluke are caught on or near the bottom in the winter trawl fishery, the temperature of the water at or near the bottom is referred to in the following discussion. The general sea bottom of the Atlantic coast extending from Cape May to Cape Hatteras (lat. 39° N. to lat. 35° lo' N.), the region frequented by the winter trawl fishery, is marked by its smoothness and gradual slope (Bigelow, 1933). The breadth of this submerged plain from the land out to the 100-fathom contour is about 70 miles off Cape May, about 60 miles off Chesapeake Bay, and about 20 miles off Cape Hatteras. From the shore, it slopes gradually until a depth of 50 to IrOO fathoms is reached. Beyond the 50- to 100-fathom zone, there is a more abrupt drop in the ocean bed, with depths of 300 to 400 fathoms recorded 5 to 10 miles beyond the edge of the Continental Shelf. Beyond this is a region of still deeper water extending down to the abyssal depths of the ocean. 38 Nesbit and Neville (1935) state: In this very deep water, the bottom temperatures are very low the year round. Inshore of this area of cold water is a zone of water between the 40 and 150- fathom depths warmed from surface to bottom by the Gulf Stream throughout the winter. Thus, there is a narrow band of relatively warm bottom water present throughout all winters (of which we have record) follow- ing in general the 100-fathom line extending from abreast of Cape Hatteras to at least abreast of Cape May and even continuing to abreast of Cape Cod and along the southern edge of Georges Bank. In contrast to this band of water which is warm both in winter and in summer, the water covering the wide inshore sub- merged plain out to about the40-fathom depth is subject to great seasonal changes, for here the temperatures are high in summer, but in winter the water is chiUed to a greater or less degree from surface to bottom. This cooling begins in the fall and takes place from inshore to offshore. In reference to this, Bigelow (1933) states: In late autumn and early winter, cooling proceeds most rapidly near the land. By mid-December the water is coldest inshore, surface to bottom; the thermal pattern is of the winter type with the isotherms (lines of equal temperature) paralleling the coastal trend at all depths; and a cold inshore boundary has been re- established to the bottom water warmer than 8°-9 C. (46°-48° F.) that washes the edge of the continent. By the middle of the month, mean temperatures are about 5°-80 c. (410-46° F.) along shore, and lO^-lS^ C. (50° -55° F.) along the outer edge of the shelf (100 fathom line) . . . and with vertical equalization so nearly complete that the difference between surface and bottom is in most cases less than 0.5° C. (0.9° F.) at given stations. Cooling proceeds through January until, by the end of the month, the temperature, surface to bottom, has ordinarily fallen below 50-6° C.(41°-43° F.) all along the coast; to 8°-9° C. (460-48° F.) midway out on the shelf; but is still IOO-I20 C. (50°-54O F.) along the outer edge of the latter. And cooling continues through the later winter until the minimum for the year is reached late in February, or early in March No thermal ev spread influx of (Chesapeake Bay Cape Hatteras) of oceanic water of onto the shelf of sometimes been grounds. idence has been found of any wide- warm coastal water into the region to Cape Cod) from the south (below any floodings of the surface with pure high temperature, nor of upsweUings the cold abyssal water, such as have postulated in the past on theoretic The amount of chilling on the shelf between Cape Hatteras and Cape May has differed considerably in each of the past five winters (1931-35). The extent of the zone of rela- tively warm water tolerated by the species has also differed in one winter compared to another winter, for obviously the width of this zone will be less during a cold winter than during a warm winter. It follows, therefore, that in some years the fish have been more or less confined and, hence, concentrated in a relatively small area, while in other years when cooling has been relatively less, the zone of warm water has extended over a wider area, and the fish are free to move over a larger expanse of sea bottom. This has been clearly demonstrated by comparing the lo- calities of best fishing with the zone of water warmer than 45° F., the latter being assumed a reasonable low temperature limit, but by no means the absolute limit tolerated by the fish (figs. 10 and 11). During the winter of 1931, the water over the entire shelf was chilled, and by the early part of March the zone of bottom water warmer than 45° F. was confined to a narrow band lying beyond the 40-fathom line. Scup, sea bass, and fluke were confined to water out near the edge of the shelf and to depths greater than 40 fathoms where the water was 45° F. or warmer. In the following winter (1932), the inshore shoal water did not cool to such low temperatures as in the previ- ous winter, and relatively warm water was present over a much greater extent of sea bottom. In that winter, scup, sea bass, and fluke were not driven as far offshore by water colder than 45° F., and the best catches were made much farther inshore and in water more shoal than in the winter of 1931. In the next winter (1933), water temperature con- ditions were about the same as in the previous winter (1932), and the best fishing was also in about the same location. Nesbit and Neville (1935) state: In the past winter (1934) there was a combination of the conditions of the three previous winters. The early part of the season (January) the water was rela- tively warm, resembling 1932 and 1933, but the latter part (March) the water was relatively cool, resembling 1931. Although air temperatures were low in January, there had not been time for any considerable cooling of the water, for the zone having bottom temperatures warmer than 45° F. apparently stUJ extended over about the same general area as in the previous two 39 °s •«i > > •« i |[ °k •sT^ •k -s -a °?! •s > •» -a I-* 8' kl , °s fe^^ ^^ °s i H: Ife^^g^^ °a •» 1^^^^ •» S o »- t- o o z o l: '•n <0 * 0 O z 0 o flC h- 0 Z < X 0 z t- z K 10 u L. ■5 K &5 < U « A 40 ?r n* t?^ ¥ ■v^ f '^ 4 ;' FEB . 1 J ■»• T4' Figure ll.~Concentration of scup based on catch per day's fishing in the southern winter trawl fishery from 1931-35. winters (1933 and 1932); and scup, sea bass, and fluke were in the more inshore, shoal region, the best catches being made in about the same location as in 1933 and 1932. In February, however, the continued severely cold weather resulted in a distinct chilling of the water so that the fish were driven to more off- shore, deeper, and warmer regions beyond the 45- and 50-fathom lines. In March, as a result of the continued cold weather throughout the previous month and the first part of March, water temperatures continued to drop; and scup, sea bass, and fluke were found not only farther offshore and instill deeperwater.butalso to the southward. Water temperatures taken in the early part of March indicated that the zone of bottom water 45° F. was confined beyond the 50-fathom line in the more northerly part of the ground (38° latitude), but extended inshore to about the 25-fathom line in the southern part (36° latitude). In the northern area fishing be- came poorer either because the scup, sea bass, and fluke were driven so far offshore and to such depths that they were beyond the reach of the gear of the ma- jority of the fleet, or because of migration to the southern area. The fishing shifted to the southern part of the ground, where the zone of relatively warm water was present over a more inshore and shoaler area. In March, both the location of fishing and the zone of bottom water 45° F. approximated the condition existing in the winter of 1931. In 1935, water temperatures by the end of the winter (first part of March) were about the same as in the preceding winter. The temperature data for 1935 were mainly from a single trip aboard a dragger fishing the cen- tral portion (easterly of Chesapeake Lightship) 41 of the general offshore region, during which temperatures were taken at several stations on a profile extending from about the 10- fathom line out to the 100-fathom con- tour. These data were supplemented by temperatures taken by certain fishing captains at various fishing spots in the general area from about lat. 36° N. to about lat. 38^ N. in depths 40 to 60 fathoms. The sharp drop in temperature did not occur in February as was the case in 1934; instead, there were indications of a gradual cooling from January through to March, so that by the latter month the zone of water 45° F. or warmer covered about the same extent of sea bottom, at least off Chesapeake Bay, as in 1934. There was, however, in 1935 a shift in best fishing loca- tion from a somewhat central inshore area, depths 20 to 50 fathoms, in January to a more offshore area extending more to the north and south in depths of 50 fathoms or more in February. In March, fishing continued to be offshore, but with some shift to a more southerly inshore area, with 20- to 50-fathom depths (fig. 11). Thus, there was general correspondence to the changes in fishing locations in 1934. Likewise in 1935, as in 1934, fishing in the northern area yielded smaller catches per unit of effort in March than in January or February; and in the southern area, on the other hand, catches were better in March than in the preceding months. Not only have the marked changes in water temperature affected the location of best fishing, but it also affected the proportions in the catch of scup, sea bass, and fluke and, in some years, croakers. Obviously, the fleet is not particularly interested in any one species, but rather in the amount of money that can be made. Sea bass and fluke usually bring a higher price than scup or croakers, and special effort is often di- rected toward the former two species. If sea bass and fluke are not easy to catch, fisher- men do not hesitate to seek scup or croakers (the latter especially in March) when they are readily available and numerous. We have already seen that the best catches have been made in bottom water warmer than 45° F. (figs. 10 and 11). This was especially true of the scup catches. For example, in 1931 when the zone of warm water was con- fined to a rather narrow band far out near the edge of the Continental Shelf, good catches were made in the southern offshore part of the ground. In that winter, more scup than sea bass or fluke were caught. Of a total catch of approximately 3,415,000 pounds landed at Virginia ports, about 50 percent was scup, 23 percent sea bass, and 27 percent fluke. On the basis of catch per day's fishing for the season, scup also exceeded either of the other two species (fig. 12, table 16). The dominance of scup in 1931 might have been the result of (1) hydrographic conditions which concentrated scup in the southern in- shore shoal portion of the zone of water 45° F. or warmer, where they were readily available to the gear, and (2) the lesser availability of sea bass and fluke, which favor somewhat different areas than scup, probably because of preference for slightly different tempera- ture and bottom type. Observations from 1931 to 1935 have revealed that the best catches of sea bass are usually taken in deeper and slightly warmer water than are scup and on rocky bottom in contrast to smooth, hard, sandy bottom frequented by scup. The best catches of fluke are usually from deeper water than are scup, but unlike either sea bass or scup, fluke are caught in more northerly part of the ground on soft, smooth, mud bottom (about lat. 37° n. to about lat. 38° 30' N., 40 to 80 fathoms). It is probable that the preference of each species for a special kind of bottom modifies the move- ments of the fish affected by changes in tem- perature, for although the water over a region may have a temperature tolerated by the species, the latter may not remain there for any length of time if the bottom is not suit- able. The best catches of croakers in some years are made in December in the region of rela- tively warm and shoal water south of Cape Hatteras, but in other winters (as in 1934 and 1935) best catches were made in March from near the beach, out to about the 50-fathom line. It is believed that this is part of the spring migration to the summer fishing grounds, for by the end of March large catches are often taken by traps in the inshore 42 ^ SCUP SEA BASS FL'JKE ^ 1932 1933 1934 TOTAL CATCH .39 38 1935 37 36 1931 1932 1933 1934 1935 I SEA BASS CATCH PER day's FISHING k ^- FLUKE lib 72" Figure 12.— Total catch and catch per day's fishing of scup, sea bass, and fluke, 1931-35. waters a few miles south of the mouth of Chesapeake Bay in Virginia (fig. 2). In the winter of 1932, when the entire body of coastal water from Bodie Island to Cape May (lat. 36° N. to lat. 39° N.) had not cooled to low temperatures as in 1931, the zone of bottom water warmer than 45° F. was far in- shore, resulting in a great increase of area in which the scup lived. That the scup scattered widely over the region is indicated by the small catches at spots scattered over the general region and the failure to find large concentrations in any special part of the ground. This temperature change also af- fected the movements of sea bass and fluke because they were not drived as far offshore as in the preceding winter and hence could 43 and did remain in this more inshore shoal area. However, they did not scatter over as extensive an area as did the scup and were more readily available. Because of this, the catch per day's fishing of sea bass increased approximately threefold between the winter of 1931 and 1932 and exceeded that of scup, which declined about 42 percent between the two winters (fig. 12). The combined total catch of all three species increased in 1932, partly as a result of the greater availability of sea bass and partly from a greater number of trips by a greater number of boats, the fleet increasing from about 50 vessels in 1931 to about 80 in 1932. Of total landings of approxi- mately 9,327,000 pounds in Virginia in 1932, about 24 percent was scup, 48 percent sea bass, and 28 percent fluke. In the next winter (1933), hydrographic con- ditions were similar to 1932; the zone of water 45° F. or warmer was widespread, scup did not concentrate, and the catch per day's fishing dropped even below 1932 (50 percent). Much of the effort was directed toward sea bass, which were again present in about the same area as in the previous winter, but in even greater numbers either because of increased availability or actually increased abundance, with the result that the catch per day's fishing increased 25 percent over 1932 and again exceeded the average catch per day's fishing for scup. The total yield of scup, sea bass, and fluke landed at Virginia ports showed a decline, however, in 1933 as compared to the pre- ceding winter. Although the number of boats increased slightly in 1933, fewer trips were made because of unusually frequent storms which interfered with or prevented fishing for extended periods throughout the season. Hence, although the catch per day increased, the total yield decreased. As in 1932, sea bass continued to dominate the fishery. Of a total catch of approximately 6,940,000 pounds landed in 1933, 49 percent was sea bass, 26 percent scup, and 25 percent fluke. In winter of 1934 the marked changes in hydrographic conditions within the season were accompanied by equally important changes in fishing location and amount and kinds of fish caught. In January, when rela- tively warm bottom water was present over a rather wide expanse of inshore coastal area, most of the fishing was done in about the same inshore shoal region as in 1933. Scup were again caught over a wide area, but were either more abundant or more readily available than in 1933, as indicated by the greater catch per day's fishing in January 1934 than in the previous January. Sea bass and fluke were caught in about the same area as in 1933. In February with sudden, sharp cooling of the inshore water, scup, sea bass, and fluke were driven to offshore, warmer regions and be- came more concentrated. Consequently, the fishing shifted to the more offshore grounds in depths of 40 fathoms or more, and the catch per day's fishing of all these species increased. The catch of scup exceeded that of either sea bass or fluke, indicating that scup were probably more inshore and more available than sea bass and fluke, the majority of which were perhaps in deeper water than that gen- erally frequented by the scup. By March, as a result of the inshore waters being cooled to such a degree by continued low air temperatures throughout February, the zone of water 45° F. or warmer was forced well offshore to the position it was in the winter of 1931 (fig. 11). Scup, sea bass, and fluke were confined to even more offshore, deeper sea bottom within this zone of relatively warm water than in the preceding month. Moreover, the fishery moved to the same area in the southern part of the grounds as that fished in 1931, and good catches consisting mainly of scup were made in depths of 30 fathoms or more. In addition, in March the average catch per day's fishing computed on landed catches was larger in the southern part of the ground. Sea bass and fluke, on the other hand, con- tinued to be sought in March in the offshore central and northern parts of the ground in depths of 50 fathoms or more, and some good catches were made. It is probable, however, that the majority of sea bass at least were far offshore and in depths beyond reach of the gear, as was probably also the case in the cold winter of 1931. 44 As a result of the effect of these hydro- graphic changes on fishing locations and on availability, the catch of scup per day's fish- ing for the season as a whole showed a marked increase in 1934 compared to 1933; for sea bass, a decrease compared to 1933; and for fluke, little change compared to the previous year. The total catch of scup, sea bass, and fluke landed in Virginia increased in 1934 compared to 1933, probably largely as a re- sult of (1) increased fishing effort by additions to the fleet, the number of boats increasing from about 85 in 1933 to about 100 in 1934; and (2) greater availability of scup, espe- cially in March with diversion of much of the fishing effort to this species. In contrast with previous winters, the composition of the total catch was more evenly balanced among the three species, for of approximately 7.8 mil- lion pounds landed in Virginia in 1934, 38 percent were sea bass, 32 percent scup, and 30 percent fluke (fig. 12). In winter of 1935, observations indicated a gradual cooling of the inshore water during January and February, and by March the zone of bottom water warmer than 45° F. was con- fined to about the same offshore region as in the latter part of the preceding winter (fig. 10). As in 1934, this continued chilling from inshore to offshore resulted in the movement of scup, sea bass, and fluke to more off- shore regions of warmer water. In January fishing was in about the same inshore shoal area (depths 20 to 50 fathoms) as in 1934 (fig. 11) with more sea bass being caught than scup or fluke; in February, with the continued chilling of the water, fish were driven farther offshore to depths of 50 fathoms or more with sea bass farther offshore and less available than the scup, which were somewhat more concentrated inshore of the bass. As a result, the catch per day's fishing of the former declined while that of the latter increased. In addition, good catches of fluke were made in the more northerly part of the offshore area, the catch per day's fishing exceeding that of the scup and of the sea bass. In March, fishing continued in the offshore, deeper area (depths of 50 fathoms or more) in the zone of 45° F. water. Sea bass were difficult to catch, probably because of their concentration in depths too great to be fished by most of the vessels and because of their preference for a region of hard rocky bottom on which considerable tearing- up of the gear occurred. Consequently, much of the effort was directed to fluke in the more northerly part of the ground where fair catches were made, and to scup concentrated inshore of the sea bass in depths 30 to 55 fathoms, as well as in the southern area in depths 20 to 50 fathoms where they could be easily reached by the gear and were in such concentrations that good catches were made (fig. 11). In March the catch per day's fishing for scup was higher than in January or February and exceeded the catches of sea bass and of fluke, both of which showed a decline compared to February. In 1935, as a result of the delayed cooling of water and the lesser abundance of the smaller sizes, the catch per day's fishing of scup decreased compared to 1934. Catch per day's fishing of sea bass also declined; fluke, on the other hand, showed an increase over the preceding winter (fig. 12). The total yield of scup, sea bass, and fluke landed in Virginia reached a record high in 1935; and for the first time since 1931, scup accounted for the greater part of the total catch. Of the 9, 683,000 pounds landed, 40 percent were scup, 28 percent sea bass, and 32 percent fluke. This increase in total catch resulted from increased fishing enort by a somewhat larger fleet in 1935 (about 120 vessels compared to about 100 in 1934). The winter of 1935 marked the first appear- ance of a new type of vessel in the southern trawl fishery, the Boston College, which previ- ously had been regularly engaged in year- round fishing principally for haddock and cod on Georges Bank and vicinity in the North Atlantic. She was launched in 1928 and Is one of the larger and more modern trawlers, being 114 feet long with a gross tonnage of 241 tons and carrying a crew of about 20. Under the command of Leo Faralora, an experienced southern winter trawl captain, she fished mainly for sea bass. Her heavier gear and. specially rigged nets gave her the advantage over the rest of the fleet of smaller, lighter equipped vessels, because she could fish the 45 deeper, rocky sea bottom where the sea bass were concentrated. When spots of good fishing are once found, the trawler could stay on these locations longer by means of her modern depthfinder. Although the trips by the linston College averaged a day longer than the rest of the fleet of small boats, her catches consistently were three to four times greater than the average for the smaller vessels. Because of the possible selection due to difference in size and modification in gear, size of vessel, and greater efficiency through more modern equip- ment, her catches have been analyzed sep- arately from the rest of the fleet and included with them only in total catch statistics. Ob- servation of her landed catches revealed about the same size composition as those of the other smaller vessels; her total catch and her catch per day's fishing, however, were materially higher because of her larger nets. Having shown that the changes in hydro- graphic conditions were accompanied by erratic changes In catch per day's fishing. It remains to point out that the marked changes in the size composition of the catch previously de- scribed were regularly associated with changes in water temperature, indicating that the latter had caused the fish to move about. For ex- ample, during the "cold" winter of 1931, when the zone of water 45° F. or warmer was relatively narrow, the principal catches of scup were in the southern part of the ground and consisted of relatively more large fish than small (fig. 8). In the following two "warm" winters (1932 and 1933), when the zone of water 45° F. or warmer extended over a com- paratively large extent of sea bottom, catch of scup consisted mostly of small and medium sizes. The scup apparently scattered over the area and were less available than in 1931, as indicated by the decline in catch per day's fishing In 1932 and 1933 compared to 1931 and by Increase In area of the plots of the localities of catch (figs. 10, 11, and 12). With the sudden chilling of the water in February 1934, the zone of warm water In March was a narrow strip out over the edge of the shelf, similar to the condition In 1931. The size composition of the catch In this southern area consisted of relatively more of the large scup. This was in direct contrast to January before the cooling began when the band of warm water presumably was present well inshore, in which area the scup catches were mainly small and medium fish. In 1935 the cooling of the water was more gradual from January to March when by the latter month the zone of 45° F. or warmer water was over about the same narrow region as In 1934. The size composition likewise changed from small and medium fish in Janu- ary to relatively more large fish in March, especially in catches made in the southern part of the ground. Thus it appears that because of the erratic changes in size composition even within short parts of a single season occurring simul- taneously with marked changes In hydrographlc conditions, that the fluctuations in the catch per day's fishing reflect changes in availability caused by movements of fish more than changes in abundance. Summary of Winter Fishery 1. The offshore fishery for scup, sea bass, and fluke has developed rapidly since the winter of 1929, both in the number of vessels and in total catch. The catch of scup in- creased from approximately 1.7 million pounds in the winter of 1931 to 3.8 million pounds in 1935. 2. The fluctuations in the catch of scup, as measured by catch per day's fishing, reflect changes in availability more than changes In abundance. 3. Sharp changes in size composition of the scup catches from large fish in one winter to smaller sizes In other winters and vice versa and similar changes within short pe- riods of a single season are apparently cor- related with changes in hydrographlc condi- tions. 4. With considerable cooling of the water in the late autumn and winter from Cape Ilatteras to Cape May, scup are generally 46 found near the edge of the Continental Shelf in depths 40 fathoms or more and particularly in the southern part of the ground (easterly of Bodic Island) in depths 25 to 50 fathoms. When relatively less cooling occurs, scup are generally scattered over the central part of the general fishing area (easterly of Chesa- peake Lightship) in depths 20 to 40 fathoms. Usually better catches are made in a "cold winter", because the scup are more con- centrated and available in a relatively small part of the fishing ground. 5. Discarding at sea of large quantities of small scup in some winters suggests the need for practical gear modification to correct this wasteful practice. TAGGING STUDIES Accurate appraisal of the general stock of scup and proper understanding of the impor- tance and causes of fluctuation in catch involve the determination of whether or not separate population units exist, and the extent of the availability of each to the general fishery or to the separate fisheries in certain localities of the general range. The identification of separate units can often be traced by a com- parison of age and size composition in the catch, varying fluctuations in yield, and more directly by tagging experiments. In the preceding discussion of the fluctua- tions in the catch of the summer and winter fisheries, evidence from the analysis of age and size composition, together with changes in catch, suggests that the summer and winter fisheries draw on the same general stock, since the catch of each has included the same broods of fish, and that fish available to the summer fisheries at various parts of the coast apparently migrate in the autumn to the region of the winter fishery and mix. Direct evidence of this was obtained from the results of tagging. From 1931 to 1934 inclusive, 7,160 scup were tagged and released in the summer and winter fisheries. In the summer fishery, scup were tagged near the northern and southern ends of the range; namely. Woods Hole, Mass., and Wildwood, N.J. In the winter trawl fishery, scup were tagged at a sufficient number of locations as to be representative of the general region being fished by the majority of the fleet. Several types of tags were used, the best results being obtained with a modified type of Scottish plaice label (external tag) and the "belly tag" (Internal tag). Modification of the plaice label and development of the belly tag is credited to Robert A. Nesbit of the Bureau (Nesbit, 1933). The external tags consisted of two lamenated celluloid disks, 25/1000-inch thick and 1/2-Inch diameter. These were attached to the mlddorsal region by a pin of pure nickel wire, .032 inch in diameter. One of the disks was white and numbered; the other was red with printed instructions of return address and notice of reward ($1). The Internal tag used In the earlier experiments consisted of a strip of bright red celluloid 25/1000-lnch thick, 1-1/4-Inch long, 1/4-inch wide, and printed and numbered (fig. 13). In later experiments, tags 1-1/4-lnch long and 5/16-inch wide were used — one side bears a number, instructions for return, and notice of reward; and the other side bears a request for additional information on locality and date of capture and length of the fish. The internal tag was inserted in the body cavity through a small incision in the body wall. To date (January 1, 1937), 113 tags have been returned (1.6 percent). Releases and recaptures of tagged scup from these experiments are listed in tables 20, 21, and 22 and charted in figure 14. From these experiments. It was definitely learned that the scup migrate in the autumn from the summer fishing grounds along the shores of southern New F.ngland and New Jersey to the winter fishing grounds off the Virginia Capes and In the spring, make a return migration from the winter grounds to the summer area. Thus, it was demon- strated that the winter fishery draws on all contingents of the stock available to the summer fishery. Doubt, however, whether the entire summer fishery draws on a common stock was raised 47 DISK TAG NICKEL PIN c 130456 ") BELLY TAG (bFU/AOn RETVUNTOBUMAUOF A Figure 13.— Types of tags used in the study of scup migrations. by the results of these tagging experiments, for they suggested the possible existence of two independent population units in the sum- mer fishery from New Jersey to southern New England. For example, the returns of tagging suggested one unit common to southern New Jersey and another to southern New England. Scup marked and released in the autumn of 1931 off southern New Jersey migrated to the region of the winter trawl fishery off the Virginia Capes as indicated by returns in the first winter subsequent to tagging and returned in the following spring to the general area in which they were tagged (fig. 14, table 20). No recaptures were reported north of the central part of the coast of New Jersey (north of Atlantic City). On the other hand, scup tagged and released in several summers at Woods Hole, Mass., were recaptured in the first winter following the tagging period in the southern winter fishery. In the subsequent spring and summers, most of the Woods Hole scup returned to the region of tagging; a few were taken as far westward as the western end of Long Island, N.Y., but of the 24 summer recaptures, only 4 were reported from New Jersey, and these were all from the northern part of the State (fig. 14, tables 20, 21). It is admitted that the small number of returns (less than 2 percent) from these experiments casts some doubt on the relia- bility of a conclusion that separate units exist near the southern and northern ends of the range of the species. Similar re- sults were secured from each of five ex- periments carried out in each of 4 years so that the segregation cannot be looked upon as reflecting exceptional behavior in a single year. The suggestion that the New York-southern New England fishery draws on a population unit separate from the New Jersey fishery as indicated by tag returns is not clearly evident from the analysis of biological and catch record data. It has been demonstrated that the same year classes that have been present in the New Jersey fishery have ap- peared subsequently in the pound net and trap fisheries at Fire Island, N.Y., and Newport, R.I. (fig. 6) and that at the latter places the catch has increased simultaneously with the appearance of these fish. If this is the result of an incursion of the same fish that were present along the New Jersey coast in the preceding year or two, it is in opposition to the results of the tagging experiments, for the latter would suggest that the New Jersey and the New York-Rhode Island fisheries draw on different population units rather than the 48 Table 20.--Suimary of recaptures of soup tagged and released in the summer and winter fisheries, 1931-33^ Released Recaptured Locality and date Fish tagged Current winter Current summer First subsequent winter^ First subsequent summer Summer fishery: Wlldwood, N. J. September-October 1931.. Woods Hole, Mass. June-July 1931 June 1932 October-November 1932... November 1933 November 1933 Nwnber 1,503 996 * = 982 * 5 447 5 341 ' 442 489 71 1,301 588 Number 6 1 Percent^ .46 .17 Number 2 13 19 2 Percent^ .13 1.30 1.93 .45 Number 3 1 1 2 1 1 2 Percent ^ .20 .10 .10 .45 .29 .23 .41 Number 8 2 5 4 9 9 9 1 Percent -' .54 .20 .51 .90 2.64 October 1934 November 1934 Winter fishery: ^ Off Virginia Capes January -March 1932 January -March 1933 1.84 .69 .34 Released Recaptured Locality and date Fish tagged Second subsequent summer Third subsequent summer Fourth subsequent summer Total Summer fishery: Wildwood, N. J. September-October 1931.. Woods Hole, Mass. June-July 1931 Number 1,503 996 * 5 982 5 341 = 442 489 71 1,301 588 Number 1 1 4 Percent^ .10 .10 .90 Numbe r 1 1 2 Percent^ .10 .22 .58 Number 2 Percent^ .44 Number 13 17 27 15 12 1 U 15 2 Percent^ .87 1.70 2.74 3.36 3.51 .23 June 1932 October-November 1932 . . . November 1933 October 1934 2,25 November 1934 Winter fishery: ^ Off Virginia Capes January -March 1932 January -March 1933 1.15 .51 ■'■ Data from tables 21 and 22. ^ Otter trawl fishery off Virginia Capes. •' Percent - recaptured x 100 . released Fish doubly tagged, but considered as "one return" when the two tags (external and internal) were recovered from same fish. ' After tagging, fish held 7 to 10 days before being released. same population units, but at different times in their period of life. On the other hand, it might be argued that the same conditions that caused the great abundance of several successive year classes along the New Jersey coast after 1927 were equally effective in producing large numbers of scup of the same year classes in a unit common to Rhode Island and New York, but for unknown reasons, perhaps environmental, the main body of those small fish are not readily available to the inshore gear at the more northern points of the range. The facts — the main season for scup at New York and Rhode Island is short (about 2 months) and their small sizes appear at the end of that short season — suggest that the scup may be available only for a short time in the inshore trap area and that not till later, as older and larger fish, do they change their habits and movements so as to become more available not only by appearaing at the beginning of the season but also by trapping more readily when moving in large spawning schools close Inshore. 49 Table 21. — Recaptures of scup tagged and released at Woods Hole, Mass., and at Wildwood, N. J., summers of 1931 to 193.i [PJJ. = pound net; F.T. ~ fkMting trap; O.T. cotter trawl; HJ.. = handUne.] Tags returned-' Released and recaptured Caught by External Internal Length when released Tag number Date Tag number Date Experiment I Released : Cm. 996 scup, June 20 to July 6, 1931, Woods Hole, P.N. Mass., marked with external tags Recaptured : Locally, 1931: Off Woods Hole, in Buzzards Bay P.N. 85162 July 2 - - 23.0 -do- P.N. 85^53 July 6 - - 29.0 -do- P.N. 85537 July 7 - - 22.0 Off Nonamesset Island, in Vineyard Sound H.L. 86202 July 18 - - 26.5 Off Nobska Point, in Vineyard Sound H.L. 85434 Aug 9 - - 24.0 Off Tarpaulin Cove, in Vineyard Sound H.L. 85696 Aug 11 - - 26.5 Off Naushon Point Shoal, in Buzzards Bay H.L. 86061 Aug 15 - - 27.0 Off Woods Hole, in Buzzards Bay P.N. 85638 Aug 20 - - 23.5 Off Tarpaulin Cove, in Vineyard Sound H.L. 85689 Aug 26 - - 28.5 Muskeget Channel, Nantucket Sound O.T. 86209 Aug 28 - - 29.0 Muskeget Channel, Nantucket Sound O.T. 85964 Aug 28 - - 31.0 Off Kettle Cove, in Buzzards Bay P.N. 85620 Oct 1 - - 19.5 Off Naushon Point Shoal, in Buzzards Bay H.L. 85810 Nov 3 - - 20.5 Southern trawl fishery, winter 1932: AO miles E. of Hog Island, Va. O.T. 85308 Jan 6 - - 19.5 Summer fishery, 1932: Off Newport, R. I. F.T. 85632 June 3 - - 29.5 Muskeget Channel, Nantucket Sound O.T. 86046 June 26 - - 26.0 Sumner fishery, 1933: Locality not determined Reported through market, Brooklyn, N. Y. - 85331 July 8 - - 21.5 Experiment 11 Released : 1,503 scup. Sept. 16 to Oct. 3, 1931 off O.T. Wildwood, N. J., marked with external tags Recaptured : Locally, 1931: 1 mile ESE. McCries Shoal Buoy O.T. 86304 Oct 3 - - 21.0 2i miles SE. | S. MoCries Shoal Buoy O.T. 86380 Oct 3 - - 24.5 Southern trawl fishery, winter 1932: 4S miles E. x N. Hog Island, Va. O.T. 86398 Feb 6 - - 24.5 35 miles E. x S. Chesapeake Lightship O.T. 82210 Mar 23 - - 24.0 Locality not determined Reported through market, Yorktown, Va. O.T. 86638 Feb 9 - - 23.5 Summer fishery, 1932: Black Fish Bank off Chinooteague Inlet, Va. O.T. 86522 May 30 - - 24.0 5 miles E. Overfalls Lightship H.L. 86526 July 3 - - 25.0 2 miles SE. McCries Shoal Buoy O.T. 82299 Sept. 27 - - 23.5 si miles NW. x W. Five Fathcan Bank Lightship O.T. 82284 Oct 14 - - 23.5 Locality not determined Reported through market, WlLnlngton, Del. - 82739 Apr 6 - - 24.0 Reported caught off Cape May, N. J. - 82376 Apr 24 - - 24.5 Reported caught off New Jersey coast - 82895 May 29 - - 21.5 Reported through market, Westchester, Pa. - 82913 Aug 1 - - 25.0 Experiment III Released : 982 scup, June -i to 8, 1932, Woods Hole, Mass., P.N. each fish marked with an external and an in- ternal tag 50 Table 21. — Recaptures of soup tagged and released at Woods Hole, Mass., and at Wildwood, N. J., sumniers of 1931 to 1934— Continued [P JJ, = pound net; F.T, = floating uap O.T. = oner trawl; HX, = handline.] Caught by Tags returned-' Released and recaptured External Internal Length when released Tag number Date Tag number Date Experiment HI— Continued Recaptured : On. Locally, 1932: Off Woods Hole, in Buzzards Bay P.N. 2449 June 9 93749 June 9 18.5 -do- P.N. 2720 June 9 94020 June 9 20.0 -do- P.N. 2863 June 9 94163 June 9 18.5 -do- P.N. 2973 June 9 94273 June 9 18.5 -do- P.N. 3189 June 10 94490 June 10 25.0 Cross Rip, Nantucket Sound O.T. 2805 June 20 - _ 22.0 Off Woods Hole, in Buzzards Bay P.N. 3045 June 21 - _ 20.0 Off Nonamesset Island, in Vineyard Sound H.L. 3090 Aug. 7 - - 23.5 Off West Chop, in Vineyard Sound H.L. 3051 Aug. 17 - - 28.5 aiset Bay, Mass. H.L. 2847 Aug. 13 - - 19.5 1 mile NW. Wing's Neck Ughtship, in H.L. 3255 Aug. 21 - - 20.0 Buzzards Bay Off Wareham, in Buzzards Bay H.L. 2579 Sept. 2 - - 19.0 Off Wings Neck, in Buzzards Bay H.L. 2524 Sept. 9 - - 19.5 On beach, Poponesset, Mass, - 3285 Nov. 16 - - 20.0 Distant, 1932: Off Narragansett Pier, R. I. F.T. 2644 June 29 - - 21.0 5 miles S. Watch Hill, R. I. F.T. 3001 Sept. 15 - - 19.5 On beach, Sokonnet, R. I. - - - 93900 Sept. 6 13.5 Locality not determined, 1932 Reported by individual, Watertown, Mass. - 2499 Aug. 23 - - 20.0 Reported through market. New York, N. Y. - 3004 Oct. 7 94304 Oct. 7 - Southern trawl fishery, winter 1933: Locality not determined Reported through market, Brooklyn, N. Y. O.T. - - 94434 Mar. 21.0 Summer fishery, 1933: Sheepshead Bay, N. Y. H.L. - - 94367 June 17 24.5 -do- H.L. 3103 Aug. 16 94403 Aug. 16 23.5 Locality not determined Reported through market, Brooklyn, N. Y. - - - 94373 July 19 22.5 -do- - - - 94382 July 20 24.0 -do- - - - 94414 Sept. 15 20.5 Southem trawl fisheiy, winter 1934: Locality not determined Reported through market, Philadelphia, Pa. O.T. - - 94068 Jan. 29 20.0 Summer fishery, 1935: Jamaica Bay, N. Y. H.L. - - 94584 Aug. 17 18.5 Experiment fV Released: 447 soup, Oct. 11 to Nov. 5, 1932, Woods Hole, P.N. Mass., each fish marked with an external and internal tag Recaptured : Locally, 1932: Off Kettle Cove, in Buzzards Bay P.N. 3569 Oct. 17 - - 21.0 Off Cross Rip Lightship, in Nantucket Sound O.T. 3435 Oct. 24 97133 Oct. 24 23.5 Southern trawl fishery, winter 1933: 30 miles E. Chesapeake Lightship O.T. 3565 Jan. 5 - - 22.0 60 miles SE. x E. Cape Henry O.T. 3779 Mar. 29 - - 24.0 Summer fishery, 1933: Sag Harbor, Long Island, N. Y. H.L. 3415 July 9 . _ 20.0 Off Wings Neck, in Buzzards Bay, Mass. H.L. - - 97382 Aug. 5 22.5 51 lable 21. --?£capt'dres of scup tagged and released at Woods Hole, Mass., and at Wildwood, N. J,, summers of 1931 to 193^--Continued [P.N, = pound nei; F.T, = floating trap; 0,T. = oner trawl; Hi, = handline,] Tags returned ^ Caught by Length when Released and recaptured External Internal released Tag number Date Tag number Date t. ^. ^.— n n^ vj Experiment IV- -Continued Recaptured — Continued Cm. Summer fishery, 1933— Continued Locality not determined Reported through market, New York, N. Y. - - - 97010 Aug. 17 21.5 Reported through market, Bethlehem, Pa. - - - 97126 June 30 23.5 Summer fishery, 193^: Harbor, Boston, Mass, H.L. _ - 97091 June 5 19.5 Off Newport, R. I. F.T. - - 97522 June 10 22.5 Off Beach Haven, N. J. P.N. - - 97207 June 16 23.5 Locality not determined Reported through market. New York, N. Y. - - - 97112 Apr. 28 20.0 Summer fishery, 1935: Locality not determined Reported through market, Baltimore, Md. - - - 97080 Sept. 2 18.5 Summer fishery, 1936: Off Newport, R. I. F.T. - - 97163 June 12 22.5 Locality not determined Reported through market, Patterson, N. J. - - - 97033 Oct. 8 19.5 Experiment V Released : 3-11 scup, Nov. 9, 1933, Woods Hole, Mass., P.N. marked with an internal tag Recaptured : Southern trawl fishery, winter 193^: Locality not determined Reported through market. New York, N. Y. - - - 113122 Feb. 2 18.5 Summer fishery, 1934; Off southern New Jersey - - - 113223 Apr. 16 20.0 Off Newport, R. I. F.T. - - 1U512 May 24 19.0 Off Rockaway Point, Long Island, N. Y. H.L. - - 113362 June 7 20.0 2 miles off Swifts Beach, Wareham, Mass. H.L. - - 113331 July 14 18.0 Off Coney Island, N. Y. H.L. - - 113116 July 23 19.0 Off Mattapoisett, Mass. H.L. - - 113434 Aug. 26 19.5 Locality not determined Reported through market, Brooklyn, N. Y. - - - 113243 Apr. 16 28.0 Reported through market, Philadelphia, Pa. - - - 113260 Apr. 20 19.5 Reported through market. Providence, R. I. - - - 113563 Sept. 12 18.5 Sumner fishery, 1936: Locality not determined Reported through market, Pawtucket, R. I. - - - 113582 May 20 19.5 Reported through market, Staten Island, N. Y. - - - 113489 Nov. 9 19.5 Experiment VI Released : 442 scup, Nov. 9, 1933, Woods Hole, Mass., P.N. marked with an external tag on occipital crest Recaptured : Southern trawl fishery, winter 1934: 50 miles E. x S. i S. Chesapeake Lightship O.T. 7268 Mar. 12 - - 19.0 52 Table 21. --Recaptures of scup tagged and released at Woods Hole, Mass., and at Wildwood, N. J., sunmers of 1931 to 1934. --Continued [P.N. = pound net; F.T, - floating irap; O.T, = oner irawl; HX. = handline.I Released and recaptured Caught by Tags returned^ External Tag number Date Internal Tag number Date Length when released Experiment Vll Released : 489 scup, Oct. 27 to 28, 1934, Woods Hole, Mass., each fish marked with an external and internal tag (U-shaped) Recaptured : Southern trawl fishery, winter 1935: Locality not determined Reported through market, Brooklyn, N. Y. Reported through market, Newark, N. J. Summer fishery, 1935 : Off Rockaway Beach, N. Y. Off Seal Rock, Newport, R. I. Off Orient Point, in Long Island Sound, N. Y. Marion Harbor, in Buzzards Bay, Mass. Off Long Branch, N. J. Off ELberon, N. J. Off Seabright, N. J. Off So. Dartmouth, in Buzzards Bay, Mass. Locality not determined Reported through market. New York, N. Y. Experiment VIII Released : 71 scup, Nov. U, 1934, Woods Hole, Mass., marked with internal tags (U-shaped) Recaptured : None to January 1, 1937 P.N. H.L. F.T. P.N. H.L. H.L. H.L. H.L. H.L. P.N. ^ To January 1, 1937. 8016 8195 8251 8191 8162 Mar. Apr. 27 10 June 12 June 16 July 2 114689 114574 114559 114286 114324 114338 July 3 Sept. 8 Sept. 15 Sept. 26 Oct. 8 Aug. 29 Cm. 22.5 22.5 21.5 22.5 20.5 18.5 20.0 19.5 19.5 20.0 21.0 A third possible explanation may be that the rise In catch at New York and Rhode Island might have been due to a combination of an Influx of "New Jersey fish" simul- taneously with the presence in average abun- dance of the same year classes of a unit local to New York-Rhode Island. This "overflow" from New Jersey might not have extended to or been of relative importance as far east- ward as Woods Hole where all fish of the northern tagging experiments were originally caught, marked, and released. Thus, it is probable that fish tagged at this point were primarily of a "local unit" and although re- turns indicated a spread of the unit westward to Rhode Island, New York, and New Jersey, distinctness and presence of this "Woods Hole" unit at the latter places may have been masked in recent years by an "overflow" of fish from New Jersey where the species have been unusually abundant since 1929. Of these three possibilities, it appears that the third, the incursion into the northern area along New York and Rhode Island of large numbers of scup of broods that had been present as smaller- sized fish along the New Jersey coast In preceding summers, together with local fish of the same year classes, caused the rise in catch in 1931 in the New York-Rhode Island pound net and trap fishery and the upward trend to 1935. As to the relationships of populations in different areas, the conclusion is that all parts of the summer fishery, together with the winter fishery, draw on a common stock of scup. 53 Table 22. — Recaptures of soup tagged and released in the southern otter-trawl fishery off the Virginia Capes, winters of 1932 and 1933 [O.T. = otter trawlj P.N. = pound net H.L. = handline) Released and recaptured Caught Tags returned ■"■ Length when by Tag number Date released 1932 Released : Cm. 1,301 scup, January to March, inclusive, in general O.T. area from lat. 35° 10' N. to lat. 38° 10' N., 20 to 60 fathoms, marked with external tags Recaptured : Southern trawl fishery: Locally, winter: 36 miles S. x E, Winterquarter Lightship O.T. 486 Mar. 19 20.0 65 miles E. Cape Henry, Va. O.T. 866 Mar. 25 26.5 20 miles SE. Winterquarter Lightship O.T. 1821 Apr. 5 25.5 Locality not determined : Reported through market, Portsmouth, Va. O.T. 150 Jan. 18 25.5 Reported through market. New York, N. Y. O.T. 837 Feb. 20 22.0 Reported through market. Old Point Comfort, Va. O.T. 1572 Apr. 11 24.5 Summer fishery: 8 miles SE. Assateague Lightship O.T. 425 May 7 23.0 Off Winterquarter Shoals O.T. 1502 May 27 27.5 Off Cape May, N. J. O.T. 840 May 29 26.5 Off North Long Branch, N. J. P.N. 779 June 28 23.5 Off Wildwood, N. J. O.T. 1624 July 5 24.5 6 miles S. Bamegat Lightship P.N. 984 July 19 23.5 Off Cape May, N. J. H.L. 752 Aug. 8 23.0 1 mile NW. Cape May Point Lightship H.L. 991 Aug. 24 23.5 ^ miles E. Chincoteague Inlet H.L. 1629 Sept. 5 28.0 1933 Released: 588 scup, January to March, inclusive, in general O.T. area from lat. 36° 40' N. to lat. 38° 10' N., 40 to 60 fathoms, marked with external tags Recaptured : Southern trawl fishery: Locally, winter: 65 miles SE. Cape Henry, Va. O.T. 4216 Apr. 10 20.5 Summer fishery: Off Beach Haven, N. J. H.L. 4248 June 17 19.0 To January 1, 1937. 54 '^ • to °9 ft •s ■to o (M o 12 H\ V ^ \ \ o ?! o °S- i .* — ■ ^t=^ 1 ?t o 1 ■ ^^^■^ J>r- ^^sl — d"~ "---..-'-->«"i»y^ °S ■ ■ S^^fl ^^fe"*. *^^-~-»« j-i ^" ^^^^ U o « 1 ■ H^l IK. i ^ BSTl^ ^ nb n •x M •I M « E o in at I. 3 ■I- Q. A U 0) q: u e E 3 U (0 o a O w I I '^ «-H 0) U 55 DISCUSSION The extent of the landings by the combined effort of the summer and winter fisheries has been the cause of concern and has raised the question as to whether or not the stock can withstand indefinitely the present amount of exploitation. Increased fishing effort during the past several years has been due largely to increased development and activity of the summer seine and trawl fisheries and more recently (1930) to the rapid expansion of the winter trawl fishery. The major fluctuations in yield prior to 1929 were mainly the result of natural changes in abundance, but since that year, changes in yield have been further affected by increased fishing effort. Despite this increase in ex- ploitation, there has been no decline in abun- dance. That the stock is not exposed to ex- cessive fishing is indicated by continued high yields of the summer and winter fisheries and by the relatively small number of returns from summer and winter tagging experiments. It does not necessarily follow that the scup fishery is entirely free from conditions and practices that may result in the future dimi- nution of the stock to the point where com- mercial fishing for the species becomes temporarily unprofitable. It has been pointed out that the present year-round fishing may be expected to continue and increase in ac- tivity. The stock may be subject to fluctuations in numbers as the result of changes in avail- ability and in variation of annual increments to the stock as the result of changes in the relative success or failure of reproduction. This may, as in the past, cause a decline in abundance so as to materially reduce the population of scup. When this happens, the decline of commercial-sized fish will be much shari)er than in the past because of the greatly Increased fishing effort. To render such inevitable decline less severe and to maintain best possible catches, the available supply should be wisely utilized. The present destruction of undersized and small unmarketable scup by both the summer d'nd winter fisheries is contrary to this end and constitutes an unnecessary obstacle to the continuance of the present high-catching rate. This practice, however, is not unpardon- able as many would assume, nor is its con- tinuance reasonably justified. Argument in support of its continuance can be based on the ground that as long as scup are abundant and in excess of market demands so much as to constitute a glut, no harm is done in destroying young fish. In fact, it may be argued that if the species is enormously abundant, "thinning out" of the stock by de- struction of the smaller sizes would Improve conditions for the older and larger market fish, because less crowding would allow better development of market sizes and tend to diminish the rate of natural mortality, all of which would tend to compensate for the de- struction of the smaller and less marketable sizes. This, it might be argued, would be comparable in results to the practice of transplanting fish from crowded areas to regions of more ample food supply and less crowding. This is the practice of many years in the plaice fisheries of certain European countries bordering the North Sea (Blegvad, 1935). However, the opinion that destruction of small fish constitutes a needless waste and obstacle to continued good yields is worthy of careful consideration, especially in light of results of the present study. Since the scup population is subject to very sharp, natural changes in abundance, it is apparent that the stock can reach exceedingly low levels irre- spective of the amount of fishing effort pre- vailing. This has been convincingly demon- strated at various times during the history of the fishery. Hence, in the periods of low abundance, the small fish of marketable size would be extremely valuable, and those below legal limit would be a source of revenue If allowed to grow another year or two. In addi- tion, the survivors among these young and small fish would have to carry the burden of the whole fishery for scup, both in winter and summer, until the next good year class or classes came along. Fishing activity by that time might be so increased that a diminished supply of small fish would be quickly caught 56 up even before they attained marketable size, leaving practically no survivors for future catching so that the yield would be mainly fish of a size now classified as "small". This is essentially what has happened in the had- dock fisheries of the North Sea (Herrington, 1935). It might also be argued that in the winter fishery sea bass and fluke, which comprise an important part of the catch because of their high market value and as such are subject to concentrated fishing effort, may not continue at their present level of abun- dance. In fact, it is the opinion of some captains engaged in this fishery that these species cannot be depended upon to furnish good catches indefinitely unless something is done to lessen the strain on them. If the fishery for sea bass and fluke becomes less remunerative, the whole effort of the winter fishery would then be directed mainly to scup and perhaps to a lesser extent to croakers. The amount of destruction of small fish, if the present practice is continued, would be greatly increased, and the available supply of the larger market sizes more rapidly diminished. This would affect not only the winter trawl fishery, but also reduce the summer catch of scup, since both the winter and summer fisheries draw on the same stock. It appears that much could be gained by eliminating or at least greatly reducing the destruction of small sizes, the principal bene- fits to the industry being: (1) Increased value within 1 or 2 years of the survivors of the small fish as they grow in size and become higher grade market fish; (2) steadier prices for the more desirable, salable sizes by elimination or reduction of market gluts, par- ticularly when small fish are especially nu- merous; and (3) prolongation of good catches when natural decline in abundance occurs. The important question then is, "How can this be accomplished?" Admittedly it is diffi- cult, for the method of correction must be practical; that is, it must not impose incon- venience or expense in excess of the probable gain. In European and certain American fish- eries, it has been demonstrated that practical modifications in gear to release undersized fish are quite feasible, but their acceptance into everyday use by the fishermen is most difficult to obtain (Russell, 1934; Herrington, 1935). In the scup fishery, as already stated, the destruction of small fish takes place both in the summer and winter fisheries. In individual cases, especially in the summer trap fishery at Newport, R.I., conscientious effort is made to release most of the undersized fish in good condition by allowing them to escape when the trap is hauled, either by means of a large mesh "sifter" or by merely running them over the cork lines. In general, however, this method of correction is not generally appli- cable to places where the catch is composed of a mixture of different kinds of fish, for the use of a "large mesh sifter" at such places might result in loss of marketable fish other than scup, either by escapement through the "apron" or by gilling. At Newport this device is used to sift catches composed almost entirely of scup and little else. In the winter trawl fishery, although many captains are cognizant of the probable effect of continued destruction of small fish on future yield, the present conditions of fishing make it practically Impossible for them to accomplish any real savings of unsalable sizes without certain changes in gear. In the otter trawl fishery, the catch is dependent on results of towing on or near the bottom usually for periods of 1 to 2 hours, depending on conditions. Consequently, the composition of the catch (kind and size of fish) is not definitely known until the haul is landed on deck. Such small fish as may be in the net are by then usually in poor condition from confinement and crowding during the towing and hauling of the net, and even if they were returned immediately to the sea, few are likely to survive. In actual practice, the trash, including both undersized and unmarketable sizes, is not cleared from the deck until all of the market fish have been culled from the haul; consequently, the trash fish are usually dead or nearly so by the time they are thrown overboard. Hence, the remedy must lie in the elimination of the undesirable sizes from the catch by escapement in good condition while 57 the net is being towed. European and American experiments have demonstrated convincingly that this can be accomplished by increasing the size of mesh, particularly in the cod end (Davis, 1934; Herrington, 1935). It is acknowledged that the adoption of such a modification in gear by the winter trawl fishery involves careful consideration of all conditions under which the fishery operates. Foremost among these is the fact that the catch of this southern fishery con- sists of several different species differing markedly from each other in shape and length. In addition to scup, the catch is composed of sea bass, fluke, croakers, and lesser quan- tities of butterfish (Poronotus tricanthus ) and squeteague (Cynoscion regalis). It is the opinion of many of the fishing captains engaged in the winter trawl fishery that a change to a larger size of mesh in the cod end in excess of that now in use would cause the loss of market- able sizes of fish other than scup. For ex- ample, it is their belief that increase in size of mesh of the cod end above present dimen- sions (2-1/2 to 3 inches stretched measure- ment) would result in the loss of the small but marketable- sized butterfish and squeteague by escapement through the mesh and the loss of good "market croakers" by gilling. Hence, the importance of "saving" the small and undersized scup relative to the catch as a whole is a debatable question. On the other hand, in some winters, de- pending on conditions, scup constitute a major portion of the catch. In addition, especially in recent years, it has comprised an important part of the catch of the summer inshore fishery, particularly along the New Jersey coast, and in some regions, as in Rhode Island, for years has accounted for prac- tically the total catch of the principal fish- eries of the region. Because of the importance of scup in the summer and winter fisheries, it is advisable to determine whether the prevailing destruction of the young and small sizes can be effectively reduced and whether this can be done without excessive loss of other market species. SUMMARY 1. The scup population of the Atlantic coast constitutes an important part of the catch of a fishing industry of major commercial and recreational importance. 2. The total catch over the past 50 years has fluctuated widely and abruptly within relatively short periods of time. 3. The catch per unit of effort has also fluctuated widely, because of changes in avail- ability which, in the summer fishery, resulted principally from changes in abundance and, in the winter fishery, from changes in move- ments of the fish. 4. Fluctuations in the catch of the summer fishery were due mainly to differences in the size of the increments added to the population by succeeding year classes, which apparently has been caused by variations in the relative success of reproduction of annual broods. 5. Fluctuations in the catch of the winter fishery were due mainly to differences in the amount of cooling of the water over the general fishing area in the several winters, scup being more available in a cold winter by being more concentrated in a relatively small and easily accessible part of the ground. 6. Although the fluctuations in catch of the summer and winter fishery have resulted from different causes, results of tagging and observations of size composition reveal that both fisheries draw on the same general stock. 7. The stock of scup is now (1935) at a high level of abundance despite the much increased fishing activity of the past 5 years, the increase resulting mainly from the devel- opment of the winter fishery and from the Increased activity of the summer otter trawl fishery. 58 8. The recovery to a record high level of abundance in 1929 following a period of un- usually low yields (1926-28) took place when the number of adult fish were not especially numerous and suggests that success of repro- duction of large broods is not wholly dependent on the presence of a large spawning reserve of old fish. 9. A natural decline in abundance can rea- sonably be expected on the basis of past history of the fishery and, when it occurs, will be greatly accelerated as compared with decline in the past because of the greatly Increased fishing activity. 10. Corrective measures effecting a reduc- tion in the prevailing destruction of under- sized and small, but legally marketable, scup would retard the expected decline in abun- dance and would tend to minimize fluctuations in the commercial catch of the species. ACKNOWLEDGMENTS As in any study of this nature, the attain- ment of results has been possible only through the cooperation, advice, and material as- sistance of many persons. Numerous members of the Bureau of Fisheries staff have assisted the authors greatly with advice on planning the study, collection and analysis of data, and the preparation of this report. Henry B. Bigelow of Harvard University provided helpful criti- cisms, particularly of that phase dealing with the hydrography of the region in which scup occurs; the Woods Hole Oceanographic Insti- tution made available the research vessel Atlantis from which many hydrographic data were collected; and Frederic McMurray, offi- cers, and crew of the Atlantis gave us their assistance. Members of the fishing indus- try, dealers, pound net and trap operators, and captains and crews of fishing vessels gave excellent cooperation in field work. They made available their establishments, vessels, and equipment in the collection of data, and provided invaluable information on record of catch, habits of fish, practices of the industry, and much other information without which this report would not have been possible. LITERATURE CITED BAIRD, SPENCER F. 1873. Report on the condition of the sea fisheries of the south coast of New England in 1871 and 1872. U.S. Com- mission of Fish and Fisheries, Part 1, Report of the Commissioner, 852 p. BIGELOW, HENRY B. 1933. Studies of the waters on the Conti- nental Shelf, Cape Cod to Chesapeake Bay. I. The cycle of temperature. Papers in Physical Oceanography and Meteorology, vol. 2, no. 4, 135 p. BIGELOW, HENRY B., and WILLIAM W. WELSH. 1925. Fishes of the Gulf of Maine. U.S. Bureau of Fisheries, Bulletin, vol. 40 (1924), part 1, p. 259-261, 263-268, 491-494. BLEGVAD, H. 1935. Transplantations of plaice from the North Sea to the Belt Sea, 1928-1933. Report of the Danish Biological Station to the Ministry of Shipping and Fish- eries, no. 39 (1934), p. 9-84. Copen- hagen. DAVIS, F. M. 1934. A mesh experiment indicating that small fish escape while the trawl is being towed. Conseil Permanent Inter- national pour I'Exploration de la mer. Rapports et Proces-Verbaux des Reunions, vol. 39, July, Appendix C, p. 22-26. HERRINGTON, WILLIAM C. 1935. Modifications in gear to curtail the destruction of undersized fish in otter trawling. [U.S.] Bureau of Fisheries, 59 Investigational Report No. 24, vol. 1, 48 p. HOLBROOK, JOHN EDWARDS. 1855. Ichthyology of South Carolina. Vol. I, 2d edition, 1860, p. 175, pi. XXV. Charleston. LYMAN, THEODORE. 1872. On the possible exhaustion of sea fisheries. Commission on Inland Fish- eries of Massachusetts, Sixth Annual Report, p. 17-40. Boston. NESBIT, ROBERT A. 1933. A new method of marking fish by means of internal tags. Transactions of the American Fisheries Society, vol. 63, p. 306-307. NESBIT, ROBERT A., and WILLIAM C. NEVILLE. 1935. Conditions affecting the southern win- ter trawl fishery. [U.S.] Bureau of Fisheries, Circular No. 18, 12 p. NEW JERSEY (STATE) BOARD OF FISH AND GAME COMMISSIONERS. 1936. Fish and Game Laws. 1922-36. Annual reports. 1921-35. NEW YORK (STATE) CONSERVATION DE- PARTMENT. 1936. The conservation law in relation to fish and game. PARR, A. E. 1933. A geographic-ecological analysis of the seasonal changes in temperature conditions in shallow water along the Atlantic coast of the United States. Bingham Oceanographic Collection, Bulletin, vol. 4, art. 3, 90 p. PEARSON, JOHN C. 1932. Winter trawl fishery off the Virginia an^ North Carolina coasts. [U.S.] Bu- reau of Fisheries, Investigational Re- port No. 10, vol. 1, 31 p. RUSSELL, E. S. 1934. Size limits and mesh regulations for sea fish. Conseil Permanent Interna- tional pour 1 'Exploration de la mer. Rapports et Proces-Verbaux des Reunions, vol. 39, July,, p. 1-5. SOUTHWICK, J. M. K., HENRY T. ROOT, and WILLIAM P. MORTON, 1893. The fluctuations in the number of fish, and the natural causes of their depletion. Annual Report of the Com- missioners of Inland Fisheries, Janu- ary session, 1893. State of Rhode Island and Providence Plantations, p. 9-16. STEINDACHNER, FRANZ, and LOUIS AGAS- SIZ. 1872. Fishes taken in Waquoit Weir (Mas- sachusetts) April 18 to June 18, 1871. Commission on Inland Fisheries of Massachusetts, Sixth Annual Report, p. 41-42. Boston. TRUE, FREDERICK W. 1887. The pound-net fisheries of the At- lantic States. In George Brown Goode, The fisheries and fishery industries of the United States. Section V, History and methods of the fisheries, vol. 1, p. 595-610. U.S. BUREAU OF THE CENSUS. 1911. Fisheries of the United States, 1908. Ch. VII. U.S. BUREAU OF FISHERIES. 1907. Statistics of the fisheries of the Middle Atlantic States for 1904. Report of the Commissioner of Fisheries for the fiscal year 1905. [U.S.] Bureau of Fisheries Document No. 609, 122 p. U.S. COMMISSION OF FISH AND FISHERIES. 1884-1905. Reports of the Commissioner, 1882 to 1905. VIRGINIA. 1936. Laws of Virginia relative to fish- eries of tidal waters. The Commis- sioner of Fisheries of Virginia. 60 Appendix W 301- -10 -O 1930 1935 1940 1945 1950 1955 0 I960 Catch ofscupinNew England, Middle Atlantic, and Chesapeake Bay S.ates. (Source: U^. Fish and Wild- life Service, Bureau of Commercial Fisheries, Statistical Digest 53.) MS #974 61 GPO a60-4e3 Created in 1849, the Department of the Interior— a department of conservation—is concerned with the management, conservation, and development 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 recreational resources are conserved for the future, and that renewable resources make their full contribution to the progress, progjerity, and security of the United States-now and in the future. UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE BUREAU OF COMMERCIAL FISHERIES WASHEsrOTON, D.C. 20240 POSTAGE AND FEES PAID U.S. DEPARTMENT OF THE INTERIOR Marine Biological Lab., 123 T Woods Hole, Mass.