c 55. W. UMFS c\RC-l>U4
NOAATR NMFSCIRC-364
A UNITED STATES DEPARTMENT OF COMMERCE PUBLICATION
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NOAA Technical Report NMFS CIRC-364
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Marine Fisheries Service
History and Development of Surf Clam Harvesting Gear
PHILLIPS. PARKER
SEATTLE, WA. October 1971
NOAA TECHNICAL REPORTS
National Marine Fisheries Service, Circulars
The major responsibilities of the National Marine Fisheries Service (NMFS) are to monitor and assess the abundance and geographic distribution of fishery resources, to understand and predict fluctuations in the quan- tity and distribution of these resources, and to establish levels for optimum use of the resources. NMFS is also charged with the development and implementation of policies for managing national fishing grounds, develop- ment and enforcement of domestic fisheries regulations, surveillance of foreign fishing off United States coastal waters, and the development and enforcement of international fishery agreements and policies. NMFS also assists the fishing industry through marketing service and economic analysis programs, and mortgage insurance and vessel construction subsidies. It collects, analyses, and publishes statistics on various phases of the industry.
The NOAA Technical Report NMFS CIRC series continues a series that has been in existence since 1941. The Circulars are technical publications of general interest intended to aid conservation and management. Publica- tions that review in considerable detail and at a high technical level certain broad areas of research appear in this series. Technical papers originating in economics studies and from management investigations appear in the Circular series.
NOAA Technical Reports NMFS CIRC are available free in limited numbers to governmental agencies, both Federal and State. They are also available in exchange for other scientific and technical publications in the ma- rine sciences. Individual copies may be obtained (unless otherwise noted) from NOAA Publications Section, Rock- ville, Md. 20852. Recent Circulars are:
315. Synopsis of biological data on the chum salmon, Oncorhynchus keta (Walbaum) 1792. By Rich- ard G. Bakkala. March 1970, iii + 89 pp., 15 figs., 51 tables.
319. Bureau of Commercial Fisheries Great Lakes Fishery Laboratory, Ann Arbor, Michigan. By Bureau of Commercial Fisheries. March 1970, 8 pp., 7 figs.
330. EASTROPAC Atlas: Vols. 4, 2. Catalog No.
1 49.4:330/ (vol.) 11 vols. ($4.75 each). Avail- able from the Superintendent of Documents, Washington, D.C. 20402.
331. Guidelines for the processing of hot-smoked chub. By H. L. Seagran, J. T. Graikoski, and J. A. Emerson. January 1970, iv + 23 pp., 8 figs.,
2 tables.
332. Pacific hake. ( 12 articles by 20 authors. ) 1970, iii + 152 pp., 72 figs., 47 tables.
March
333. Recommended practices for vessel sanitation and fish handling. By Edgar W. Bowman and Alfred Larsen. March 1970, iv + 27 pp., 6 figs.
335. Progress report of the Bureau of Commercial Fisheries Center for Estuarine and Menhaden Research, Pesticide Field Station, Gulf Breeze, Fla., fiscal year 1969. By the Laboratory staff. August 1970, iii + 33 pp., 29 figs., 12 tables.
336. The northern fur seal. By Ralph C. Baker, Ford Wilke, and C. Howard Baltzo. April 1970, iii + 19 pp., 13 figs.
337. Program of Division of Economic Research, Bureau of Commerecial Fisheries, fiscal year
1969. By Division of Economic Research. April
1970, iii + 29 pp., 12 figs., 7 tables.
338. Bureau of Commercial Fisheries Biological Lab- oratory, Auke Bay, Alaska. By Bureau of Com- mercial Fisheries. June 1970, 8 pp., 6 figs.
339. Salmon research at Ice Harbor Dam. By Wesley J. Ebel. April 1970, 6 pp., 4 figs.
340. Bureau of Commercial Fisheries Technological Laboratory, Gloucester, Massachusetts. By Bu- reau of Commercial Fisheries. June 1970, 8 pp., 8 figs.
341. Report of the Bureau of Commercial Fisheries Biological Laboratory, Beaufort, N.C., for the fiscal year ending June 30, 1968. By the Lab- oratory staff. August 1970, iii + 24 pp., 11 figs., 16 tables.
342. Report of the Bureau of Commercial Fisheries Biological Laboratory, St. Petersburg Beach, Florida, fiscal year 1969. By the Laboratory staff. August 1970, iii + 22 pp., 20 figs., 8 tables.
343. Report of the Bureau of Commercial Fisheries Biological Laboratory, Galveston, Texas, fiscal year 1969. By the Laboratory staff. August 1970, iii + 39 pp., 28 figs., 9 tables.
344. Bureau of Commercial Fisheries Tropical Atlan- tic Biological Laboratory progress in research 1965-69, Miami, Florida. By Ann Weeks. Oc- tober 1970, iv + 65 pp., 53 figs.
346. Sportsman's guide to handling, smoking, and pre- serving Great Lakes coho salmon. By Shearon Dudley, J. T. Graikoski, H. L. Seagran, and Paul M. Earl. September 1970, iii + 28 pp., 15 figs.
347. Synopsis of biological data on Pacific ocean perch, Sebastodes alutus. By Richard L. Major and Herbert H. Shippen. December 1970, iii + 38 pp., 31 figs., 11 tables.
Continued on inside back cover.
A1M0SP-
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U.S. DEPARTMENT OF COMMERCE
Maurice H. Stans, Secretary
NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION Robert M. White, Administrator
NATIONAL MARINE FISHERIES SERVICE Philip M. Roedel, Director
NOAA Technical Report NMFS CIRC-364
History and Development of Surf Clam Harvesting Gear
PHILLIPS. PARKER
c O
5 O
SEATTLE, WA. October 1971
For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C., 20402 - Price 30 cents Stock number 0320-0035
Clam boats dredging for clams with wet (hydraulic) dredges along the east coast of the United States.
CONTENTS
Page
Introduction 1
Manual collecting methods 2
Hand collecting 2
Rakes 2
Tongs 2
Power collecting methods 2
Scraper-type dredges 2
Hydraulic dredges 4
Experimental gear 7
Vessels 12
Summary 12
Literature cited 13
FIGURES
Page
1. — Raking and tonging for surf clams from a dory in shallow water
depths 3
2. — Types of rakes used for hand collection of surf clams 4
3. — "Long Island" hydraulic bar clam dredge of the type which became
popular with the Long Island clammers 5
4. — Early model hydraulic dredge showing sled under bag, one of the early modifications which led to the development of the standard
dredge with its after-cage built of steel bars 5
5. — Photograph of largest hydraulic jet dredge in use today by the surf clam industry. This is an 84-inch dredge used aboard the 136-ft
Gail Borden 6
6. — Gasoline-driven pump on the deck of a clamming vessel 7
7. — Classic 40-inch hydraulic jet dredge used by the majority of fishing vessels operating along the coast of New Jersey and Maryland dur- ing the late 1950's and up to the present time 8
8. — Drawing of a 48-inch hydraulic clam dredge built for clam survey work aboard the National Marine Fisheries Service research vessels
Delaware and Delaware II 9
9. — Constant delivery pump system aboard the Gail Borden.
A — Separator, where all material transported up discharge hose empties for washing and separation of clams from the rest of the material. B — Escalator, where surf clams enter to be carried up to sorting table or unit. C — Clam jetting water hose. D — Air hose. E — Transporting hose, for carrying material from up- take unit to separator. F — Waste discharge units, through which other material is dumped back overboard 10
in
10. — Constant delivery pump system dredge aboard the Gail Borden. A — Clam jetting water supply hose. B — Compressed air hose. Air is supplied through this hose to the uptake unit where it mixes with the water in the hose, generating the upward movement of water within the hose. C — Receiver. Material jetted out of bottom and picked up by the dredge knife passes into this area and then into the uptake of the discharge hose. D — Transport- ing hose for carrying dredge material from receiver to separator ... 11
11. — Electrical submersible pump used for supplying water to dredge jets. A — Submersible pump discharge opening, 8-inch inside diam. B — Strainer surrounding pump, mesh size approximately 1-inch2. Any object passing through this strainer will pass through pump . . 12
12. — Electrical submersible pump shown as mounted to 48-inch clam dredge. A — 8-inch discharge, connected to header. B — Water- tight electrical junction. C — Header 12
13. — Clamming vessel showing adaptation of gear to take dredge in over
the stern while steaming 13
14. — Stern chute clam dredge ramp used aboard Delaware II 14
15. — A converted shrimp boat. One of the several different vessel types
which were converted for surf clam dredging 15
IV
History and Development of Surf Clam Harvesting Gear
By
PHILLIP S. PARKER, Fishery Biologist
National Marine Fisheries Service1
Exploratory Fishing and Gear Research Base
Woods Hole, Massachusetts 02543
ABSTRACT
The development of harvesting gear for surf clams, Spisula solidissima, along the eastern coast of the United States is reviewed from early times up to the present.
Early clamming was done by hand using rakes or tongs, while today the in- dustry depends upon large, efficient dredges operating from stable vessels. Little gear development took place prior to World War II; however, since that time, the industry has made rapid strides in the development of harvesting gear. Today this trend is still very much in evidence, with gear constantly being modified for adaptation to newer vessel types.
Most gear development work has been the result of the surf clam industry itself. However, the Federal Government, in cooperation with industry, has de- veloped several pieces of equipment for adaptation to clamming gear.
INTRODUCTION
The history of the development of harvest- ing gear for surf clams, Spisula solidissima, along the eastern coast of the United States has been only touched upon by various authors reporting on this species. However, to date, no comprehensive description of the gear has been written. Prior to World War II, the ef- fort for development of this type of gear was rather limited. Probably this was because the harvesting equipment used at that time was sufficient to maintain an adequate supply of surf clams for both fish bait and the limited market available for human consumption. The World War II years, with the search for good
1 Formerly Bureau of Commercial Fisheries Explor- atory Fishing and Gear Research Base, Gloucester, Mass. 01930.
sources of high protein food by both Govern- ment and industry, provided the impetus for a tremendous increase in the market demand for surf clams. Due to this demand, rapid de- velopment of a variety of surf clam harvesting gear followed. Many kinds of dredges were devised by the industry before the hydraulic jet dredge was developed. Different types of hauling gear and boat sizes were also tried during this period.
Today further radical changes are being made to the so-called "standard" hydraulic jet dredge in an effort to increase its efficiency. Prior to 1963, clam gear research and devel- opment were exclusively pursued by the surf clam industry. This group had been respon- sible for almost all of the changes in the de- sign and modification of the clam harvesting equipment. However, units of the National
Marine Fisheries Service are now actively co- operating with the surf clam industry and are expending considerable time and effort in the development of new types of clam harvesting- gear suitable for use in exploratory surveys and biological studies.
MANUAL COLLECTING METHODS
Hand Collecting
In all probability, the first surf clam harvest- ing method employed in this country was that practiced by the American Indian. Goode (1887) quotes one of the earliest "tracts" writ- ten upon our natural history, Wood's "New England Prospect" (1634), which says that along Nahant [Massachusetts] Beach, the sea "after storms casts up greate store of greate Clammes which the Indians taken out of their shells conny home in baskets," and which also says "Clammes as big as a halfe-penny loof, which are greate dainties amongst the natives."
Another early and simple method of harvest- ing was employed by farmers along the New Jersey coast, who, after finding large quantities of surf clams washed ashore by severe storms, would shovel them into their wagons to be hauled away for field fertilizer, for hog and poultry feed, or for use as bait. At about the same time (approximately 1878), a new fish- ery was beginning at Dennisport, Mass., where the surf clam was harvested by means of clam rakes operated from dories which were either hand or sail propelled. This method of dory- hand raking for clams was only used out to about V/o miles from shore (Fig. 1). The rakes were made of iron with wooden handles and measured from 20 to 27 ft in length; the rake heads had 17 to 25 teeth and cost from $5 to $8 apiece (Fig. 2). Most of the raking was done in water depths of about 8 ft and at ebb tide, although at times the fishermen worked as deep as the length of the rake (ap- proximately 18 ft) and tong handles would permit (Goode, 1887). Potato forks or sim- ilar instruments are used to harvest the surf clam in certain areas of Canada.
Rakes
There are two types of rakes used in the commercial fisheries today. These are the com- mon clam rake and the bull rake (Fig. 2) . The
common rake is similar to a garden rake except that the teeth are larger and sharper. It is equipped with a wire mesh basket or "apron" which holds the catch, and it is generally used in very shallow water. (A modification is used in Maine for gathering Irish moss (Dumont and Sundstrom, 1961).)
The bull rake, used generally in New Eng- land, is a large implement with a head between 20 and 30 inches wide (Fig. 2). It has long, curved teeth which are about 9 inches long. Unlike the common hand rake, the bull rake does not have a basket or apron, its handle is usually longer, and it is used in deeper water than the hand rake (Dumont and Sundstrom, 1961).
Like the common rake, the bull rake has nu- merous modifications. One of these is called the Shinnecock rake. This rake is used only in Maryland. Its long, curved teeth are pro- gressively shorter toward the ends of the rake head (Fig. 2) and are shaped to form a basket in which the clams rest as they are raised from the bottom (Dumont and Sundstrom, 1961).
Tongs
Another implement used during the early days of the industry for gathering surf clams was the hand tong (Fig. 1). Hand tongs are actually a pair of rakes attached to the ends of two long poles which are up to 20 ft in length and are fastened together like a pair of scissors with the fulcrum near the lower end. A bas- ket-like frame is attached to the back side of each rake in order to hold the catch (Dumont and Sundstrom, 1961).
The production potential of rake and tong gear was obviously limited, and before any large expansion could take place in the surf clam industry, development of more efficient harvesting gear was necessary.
POWER COLLECTING METHODS
Scraper-Type Dredges
During the 1920's, scraper-type dredges were developed which could be towed behind power boats. These were usually 18 to 28 inches wide with a knife blade (rather than teeth) located in front of a scoop which sloped upward and backward toward a bag for hold-
Figure 1. — Raking and tonging for surf clams from a dory in shallow water depths
ing the catch. The blade scooped into the bottom to a depth of 6.5 to 9 inches. The so- called "Sheepshead Bay" dredge had a more or less straight leading edge to the knife and was adjustable to a desired depth. These dredges were towed by a rope, usually fastened to a special stanchion, and were hauled aboard either by a towing rope or by an additional steel cable attached to the dredge. Both meth-
ods used a powered winch (Westman-). No further significant changes were made in the dredges for many years. However, the design of some dredges became slightly modified, e.g., the knife was rounded so that the leading edge became an arc.
- Westman, J. R. 1946. On the origin, development and status of the surf clam industry, 1943-45. New York Conservation Department, Bureau of Marine Fisheries. Unpublished manuscript, 10 p.
Experiments were made with sleds under the bag in attempts to clear the mud away from the clams more rapidly. In spite of these modifications, the scraper dredges piled up the sand badly, which choked the forward parts of the bag (Westman, see footnote 2). Be- cause of the deficiencies in these dredges, as well as undesirable results from their oper- ation, experiments were conducted in the mid- 1940's by the surf clam industry which led to the development of the more efficient hydraulic jet dredge.
Hydraulic Dredges
The hydraulic jet dredge was developed by jetting water directly into the conventional "dry" dredge. The first units built were small but were effective enough to prove their super- iority over simple scraper dredges. One of the main advantages of the hydraulic jet dredge was its tremendous reduction in the number of broken clams and damaged meats taken in the catches. By utilization of the water jets, the area that could be dredged during a tow was more than doubled. This made possible the commercial harvesting of clam populations of far less density than was previously feasible. Furthermore, regions of hard bottom which were previously unsuitable for dredging now became productive.
Many experiments using different types and orientation of jets were made. Also, trials using various types and sizes of water pumps, as well as types and sizes of hose, were con- ducted before the major difficulties were over- come and boats of the commercial fleet were converted to hydraulic jet dredge gear.
The most popular of the early types of dredges was the "Long Island" hydraulic bar clam dredge (Fig. 3) with three jets (West- man, see footnote 2). Water was pumped to these jets by a gasoline-driven pump located aboard the fishing vessel through a 2^-inch canvas fire hose. Special hose was later de- veloped by the rubber industry for this spe- cific purpose. This new hose could withstand internal pressures up to 150 psi even with ex- tensive outside wear from the abrasive action of sand, gravel, etc.
Figure 2. — Types of rakes used for hand collection of surf clams.
The development of the hydraulic jet dredge did not stop here. Although the basic prin- ciples remained unchanged, the size and effi- ciency of the gear were continually increased during the period 1945-65 (Fig. 4). The dis- covery of large unexploited surf clam beds off the coasts of Maryland and New Jersey (in 1949) resulted in a shifting of the center of the industry from the Long Island area to the coasts of New Jersey and Maryland. Because of the increased availability of clams, the in- dustry was able to expand rapidly and to in- crease the size and efficiency of the gear used to fish these beds. Dredge sizes have now reached a maximum size of 84 inches in width (Fig. 5).
Correspondingly, the size of water pumps has been increased to maintain the proper pressured flow of water required by these larger dredges. The volume of the pumps has
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Hose
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Figure 3. — "Long Island" hydraulic bar clam dredge of the type which became popular with the Long Island clammers. (Drawn by Carl Rich after C. E. Petite and P. W. G. McMullon, Fish. Res. Board Can., Bull. 102, Ottawa, 1955.)
SLED
DREDGE
KNIFE
Figure 4. — Early model hydraulic dredge showing sled under bag, one of the early modifications which led to the development of the standard dredge with its after-cage built of steel bars.
Figure 5. — Photograph of largest hydraulic jet dredge in use today by the surf clam industry. This is an 84-inch dredge used aboard the 136-ft Gail Borden. Note size of auxiliary gear and deck equip- ment required for the operation of this size dredge. Two 6-inch inside diam. water supply hoses are required for the jetting action of this dredge on the bottom.
Figure 6. — Gasoline-driven pump on the deck of a clamming vessel.
been increased from a few hundred gallons per minute up to 3,500 gpm. One commercial boat is now using two pumps to supply the required amount of water. Hose size has been increased from 21/2- up to 61/^-inch inside di- ameter with some boats doubling-up on the smaller 6-inch hose. As the deck-mounted, gasoline-driven pumps (Fig. 6) became inad- equate, they were replaced with diesel-pow- ered units installed below decks. This modi- fication not only increased the available deck space but also improved the operational safety of the vessel.
The dredge most generally used between the late 1950's and the present has been a 40-inch model (Fig. 7). This size dredge is particu- larly suited to the handling and towing capa- bilities of most of the commercial vessels in the clam fleet.
Although the size of this dredge is well standardized, many minor modifications are consistently being made in an attempt to im- prove on its efficiency. These modifications consist mainly of changes in the size and ar- rangement of the water jets, variations in placement and shape of the jet manifold, changes in the volume and pressure of water supplied to the jets, changes to the shape and contour of the dredge knife, improvements in the attachment of the knife to the dredge, changes of the knife depth setting, variations of towing speed, shape, and slope of the sled
floor, construction and attachment of the chain bag, and towing attachment between the dredge and sled. During this period of development, local modifications to the dredges reflected dif- ferences in the characteristics of the areas in which they were being used. The shape of the dredge might be slightly different or the type of jet header and arrangement of the jets might be different; also, the type and shape of the knife could vary from area to area. Be- cause of these variations, the physical state of the hydraulic jet dredge can be considered to have been almost constantly changing (Fig. 8) .
EXPERIMENTAL GEAR
As the commercial fishing effort increased on the larger clam beds which were located within easy distance from ports and processing plants, these beds have sustained consistent and heavy fishing pressure. As the production rate over these beds leveled out, rich beds located at greater distances from ports and plants have been used. However, the balance maintained between the fishing time to be gained or lost by traveling shorter and longer distances, vs. the production rate(s) of the various fishing grounds, became an important consideration. It now appears that in order to maintain the desired production level, either faster boats or more efficient fishing gear is needed. The lat- ter proposal seems to be the more practical solution. One approach to updating or other- wise improving the gear and fishing method is to adopt methods and gear used by other marine industries for use in the surf clam industry.
Early in 1963, a member of the surf clam industry became interested in the development of an airlift system based upon the principle now used for collecting diamonds off the south- ern coast of Africa. The principle involved is that of pumping air down to the dredge where the air is directed into the bottom of a large hose extending from the dredge to the boat deck. The air causes the mixed water-air col- umn within the tube to become lighter than the outside water and generates an upward movement of the water within the hose. The water flowing into the bottom of the hose to replace the water which has moved upward
Figure 7. — Classic 40-inch hydraulic jet dredge used by the majority of fishing vessels operating along the coast of New Jersey and Maryland during the late 1950's and up to the present time. Note that the dredge itself is all enclosed except for the bottom and forward section of its top. Loose aprons built out of rings are used to enclose the space between the dredge and sled to prevent loss of clams between the two units. In addition, chain attachments are used between the two units for towing purposes. Attached to the sled is the chain bag built of 3-inch scallop rings and connectors. This dredge is equipped with a straight edge knife. Many dredges use a V-shaped knife that floats on springs and digs into the bottom only after the water to the jets is turned on. In use of spring-mount- ed blades, the knife settles into a trough which is jetted out by the water. Dredges with this type of blade also use a V-shaped manifold as compared to the straight manifold shown her"e. The clam jetting hose shown has been built especially for clam jetting and has a 5-inch inside diam.
3/j jg to support chain bay
! -i — f^
fyes at front of t/ed t.
Figure 8. — Drawing of a 48-inch hydraulic clam dredge built for clam survey work aboard the National Marine Fisheries Service research vessels Delaware and Delaware II.
carries the material dredged from the bottom with it. When fully developed, this system will offer the possibility of continuous dredging without interruption and loss of fishing time for hauling, emptying, and resetting the dredge. In addition, the catch can be constantly mon- itored, and small beds can be effectively fished. After preliminary investigation of the feas- ibility of this method, Snow Canning Company of Pine Point, Maine, began to assemble the needed gear and equipment for building an air- lift system on their vessel Gail Borden. After building and pretesting component units of the system, a working model was given lim- ited fishing tests during the spring and sum- mer of 1964. Many "bugs" were found, and further effort for modifying the system to cor- rect deficiencies continued. Near the middle of 1965, the redesigned unit was ready for
further testing (Figs. 9 and 10). While some minor deficiencies remained, test results were encouraging enough to warrant the develop- ment of a complete system for future clam harvesting.
In addition to these developments, submers- ible pumping systems have been developed to replace the older type vessel-mounted pumping systems used on all the commercial clam boats today. Such a system has an electrically driven submersible pump (of sufficient power and rating) (Fig. 11) mounted on the forward end of the clam dredge. The discharge end of the pump is connected directly to the dredge man- ifold (Fig. 12). Electrical energy is supplied to the pump from a vessel-mounted generator feeding power through a watertight power cable which is stored on a deck-mounted hy- draulically-driven reel. The main advantage
Figure 9. — Constant delivery pump system aboard the Gail Borden. A — Separator, where all material trans- ported up discharge hose empties for washing and separation of clams from the rest of the material. B — Escalator, where surf clams enter to be carried up to sorting table or unit. C — Clam jetting water hose. D — Air hose. E — Transporting hose, for carrying material from uptake unit to separator. F — Waste discharge units, through which other material is dumped back overboard.
10
\
-. - f l #7
Figure 10. — Constant delivery pump system dredge aboard the Gail Borden. A — Clam jetting water supply hose. B — Compressed air hose. Air is supplied through this hose to the uptake unit where it mixes with the water in the hose, generating the upward movement of water within the hose. C — Receiver. Material jetted out of bottom and picked up by the dredge knife passes into this area and then into the uptake of the discharge hose. D — Transporting hose for carrying dredge material from receiver to separator.
11
585#
Figure 11. — Electrical submersible pump used for sup- plying water to dredge jets. A — Submersible pump discharge opening, 8-inch inside diam. B — Strainer surrounding pump, mesh size approximately 1-inch2. Any object passing through this strainer will pass through pump.
Figure 12. — Electrical submersible pump shown as mounted to 48-inch clam dredge. A — 8-ihch dis- charge, connected to header. B — Watertight elec- trical junction. C — Header.
of this system is that it does away with hand- ling the heavy hose required for the older pumping system while requiring less work to gear up.
Another recent innovation in clam gear is the adaptation of the stern trawler type ves- sel to clam dredging. This is accomplished by modifying the handling gear so that the dredge can be hauled in over the stern of the vessel (Figs. 13 and 14). This method of handling the dredge, along with some constant delivery system, may prove to be the most efficient meth- od of harvesting the sea clam in the future.
VESSELS
Small dories and skiffs were first used by hand rakers and tongers to collect surf clams from the shallow waters along the coast. As mechanical methods for harvesting were de- veloped during the 1920's, other types of boats were utilized to handle the new type of equip- ment. Party boats, skiffs, and conventional small draggers became the backbone of the commercial fleet. After widespread use of the hydraulic jet dredge became established, larger size vessels were needed. To meet the demand, regular fishing vessels were converted in order to accommodate this newer and more efficient method of dredging. Previously, these larger boats were generally used as shrimp boats (Fig. 15), oyster boats, fish draggers, sardine boats, and conventional military boats. The range of size for these boats is from 31 to 136 ft in length and from 14 to 160 gross tons. Most vessels are powered by diesel engines and are operated, when dredging, by two- or three-man crews, depending upon the size of the vessel.
SUMMARY
The development of surf clam harvesting gear is traced from early times to the present.
During this period of time, very little devel- opment work was accomplished prior to World War II. After this, rather rapid strides were made in development work by the surf clam industry and in the past several years by the Federal Government in cooperation with the surf clam industry.
12
The hydraulic jet dredge became the main piece of surf clam harvesting gear in use today.
Many modifications have been made or in- corporated into this piece of gear since its in- ception. Today, the hydraulic jet dredge is be- ing successfully operated from stern trawler type of boats.
This gear has been adapted for use on many different sizes and types of vessels, most of which have been converted from some other type of fishery.
LITERATURE CITED
DUMONT, W. H., and G. T. SUNDSTROM.
1961. Commercial fishing gear of the United States. U.S. Fish Wildl. Serv., Circ. 109, iv + 61 p.
GOODE, G. B.
1887. History and methods of the fisheries. In G. B. Goode, The fisheries and fishery industries of the United States. U.S. Comm. Fish and Fish., Sect. 5, Vol. 2: 581-615.
Figure 13. — Clamming vessel showing adaptation of gear to take dredge in over the stern while steaming.
L3
Figure 14. — Stern chute clam dredge ramp used aboard Delaware II.
11
.** \_ **
Figure 15. — A converted shrimp boat. One of the several different vessel types which were converted for surf
clam dredging.
i:»
GPO 998-583
349. Use of abstracts and summaries as communica- tion devices in technical articles. By F. Bruce Sanford. February 1971, iii + 11 pp., 1 fig.
350. Research in fiscal year 1969 at the Bureau of Commercial Fisheries Biological Laboratory, Beaufort, N.C. By the Laboratory staff. No- vember 1970, ii + 49 pp., 21 figs., 17 tables.
351. Bureau of Commercial Fisheries Exploratory Fishing and Gear Research Base, Pascagoula, Mississippi, July 1, 1967 to June 30, 1969. By Harvey R. Bullis, Jr., and John R. Thompson. November 1970, iv + 29 pp., 29 figs., 1 table.
352. Upstream passage of anadromous fish through
navigation locks and use of the stream for spawn- ing and nursery habitat, Cape Fear River, N.C 1962-66. By Paul R. Nichols and Darrell E. Louder. October 1970, iv + 12 pp., 9 figs., 4 tables.
356. Floating laboratory for study of aquatic organ- isms and their environment. By George R. Snyder, Theodore H. Blahm, and Robert J. Mc- Connell. May 1971, iii + 16 pp., 11 figs'.
361. Regional and other related aspects of shellfish consumption — some preliminary findings from the 1969 Consumer Panel Survey. By Morton M. Miller and Darrel A. Nash. June 1971, iv -f 18 pp., 19 figs., 3 tables, 10 apps.
UNITED STATES DEPARTMENT OF COMMERCE
NATION \L OCEANIC a U.'AOSFHERIC ADMINISTRATION
NATIONAL A'^RINE FISHERIES SERVICE
SCIEN.IF'C P'JBLICUIONS STAFF
BLDG. 67, NAVAL GUP'uRT ACTIVITY
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