INTRODUCTION
Today I would like to take you on a tour of the east and gulf coasts of the United States to review the past and present status of molluscan aquaculture. Robert D. Wildman has already reviewed the current molluscan aquaculture projects under the Sea Grant Programs for this area, so I will cover these projects only briefly in my presentation. Because of the limited time, I plan to center my discussion around the culture of three species of molluscs, the Eastern oyster, Crassostrea virginica; the hard clam, Mercenaria mercenaria; and the bay scallop, Aequipecten irradians. Although there are other important commercial molluscs found along our east and gulf coasts, such as the surf clam, Spisula solidissima; ocean quahog, Artica islandica; sea scallop, Placopecten magellanicus; sunray venus, Macrocallista nimbosa; calico scallop, Aequipecten gibbus; and the soft-shell clam, Mya arenaria, these species are being hunted. Little or no attempt is being made to farm these species at the present time.
I will review the fishery for the oyster, hard clam, and bay scallop and describe past and present attempts to farm each species.
The Eastern oyster, Crassostrea virginica, (also called the American or Virginia oyster) ranges along the entire east and gulf coasts. Peak of production, near 170 million pounds, was reached in the 1890's. Since then, landings have been on the decline with an apparent leveling off in the 1960's--around 50-60 million pounds (Engle, 1966). Unlike Japan, oysters along the east and gulf coasts are grown almost entirely on the bottom. The national average is reported to be only 0.004 tons per acre per year, while the best yield on the bottom is 2.0 tons per acre per year (Ryther and Bardach, 1968). These yields are extremely low when compared to those of Japan where 23.3 tons per acre per year are being harvested using off-bottom methods.
Not only are most of the U.S. methods of growing oysters extremely
primitive, but so are our ways of harvesting. In Maryland, the state that
has the largest annual production of oysters, oystermen catch oysters with
hand tongs and patent tongs and in dredges pulled along the bottom by sailboats.
Laws in this state prevent the use of more mechanical means such as the
hydraulic dredges, except on private leases.
Realizing that the production of oysters has been on the decline, many
private companies, state and federal agencies, and universities have in
recent years initiated programs in an attempt to modernize the oyster industry.
I would like to review some of these programs at this time.
Under the U.S. Government's Federal Aid Program the State of New Hampshire has for 3 yr (1966-69) investigated the possibility of producing seed oysters and growing oysters using off-bottom techniques (Ayer, Smith, and Acheson, 1970). New Hampshire is at the northern limit of the oyster's natural range, and because of the cold waters, growth is slow. Still in certain areas, like Great Bay, the water warms suffciently so that the natural oyster populations can spawn and setting does occur. It appears from their studies that a limited amount of seed could be produced annually, but intensity would vary greatly from year to year.
Production of oysters in Massachusetts is small and only 72,100 pounds of meats were harvested in 1970. Yet, during the 10-yr period from 1910 to 1919, an annual yield of 1.2 million pounds was realized. Up to recent times, all oysters were grown on leased bottoms. Because of the cold waters, it takes up to 5 yr for oysters to reach market size. Massachusetts oysters are of excellent quality and are eaten raw on the half shell. The wholesale price is as high as $22.00 per bushel (7,920 yen, 250 oysters to the bushel).
In 1956, the Bureau of Commercial Fisheries (now the National Marine Fisheries Service) initiated studies on the off-bottom culture of oysters in Massachusetts. Because of the oyster's high price, it was felt that this method of culture may be commercially feasible.
A log raft was constructed and moored in Oyster Pond River, Chatham, Mass. Oyster and scallop shells, containing seed oysters, were strung on #14 galvanized wire, each shell separated by a 3-inch piece of plastic tubing. The strings were suspended from the log raft for I yr, and then the oysters were removed and planted on the bottom for an additional year.
The results of the study showed that oysters grew almost twice as fast as those on the bottom. Survival of raft oysters was about 6 times greater than for the bottom grown oysters. Meat quality was excellent. Finally, the results indicated that raft culture appeared commercially feasible in Massachusetts (Straw, 1962).
Similar raft studies were conducted by Matthiessen and Toner (1966) on Martha's Vineyard, Duke's County, Mass. These results showed that suspension techniques offered a promising method of oyster culture in the county. The authors felt that further refinement of suspended materials was needed and that rafts which could be conveniently submerged below the surface should be developed because many areas were exposed to storms and moving ice.
It was not until 1970 that off-bottom culture was attempted commercially- in Massachusetts. Aqua Dynamics Corporation, Wareham, Mass. has begun to grow oysters suspended from iron-pipe racks (10 ft x 71/2 ft x 5 ft) that rest on leased bottom. This year they plan to have 575 racks. Each rack contains 154 5-ft strings which will yield approximately 60 bushels of oysters. The corporation hopes to market their oysters. which will measure from 2 to 21/2 inches, in 11/2 yr. In a cooperative study with the National Marine Fisheries Service. Division of Marketing it was learned that these small oysters have excellent consumer acceptance on the half shell.
An 8-ft high tower has been constructed adjacent to the Wareham River for growing oysters (Zahradnik and Johnson, 1970). A series of 4 ft x 4 ft tray-pallets containing up to 50 bushels of oysters are in the tower. Water is supplied to the tray-held oysters through a pipe running up the center of the tower. It is planned to operate the tower for 1 yr, including a winter season.
In 1910 over 15 million pounds of oyster meats were harvested from Rhode Island. In 1970 only 146 pounds of meats were landed. Although many factors have contributed to this decline, pollution of Narragansett Bay is the probable leading factor.
At present, one company is attempting to grow oysters suspended from rafts (patent pending) in a small tidal pond. This is a small operation and only 800 bushels were expected to be harvested annually.
In the late 1800's, Connecticut was producing over 10 million pounds of oyster meats annually. In 1970, only a little over 125,000 pounds of meats were landed. Set failures have contributed greatly to the drop in production. Loosanoff (1966) reported that during the years 1925-60, a good commercial set has occurred only 8 times. In addition, factors such as slow growth, predators, siltation, pollution, and hurricanes have all contributed to the decline of this once prosperous industry.
In an attempt to help the oyster industry of this area, a center for shellfish research was established by the Bureau of Commercial Fisheries at Milford, Conn. The Milford laboratory has become world renown for its work in developing shellfish hatchery techniques (Loosanoff and Davis, 1963). Shellfish hatcheries are now located throughout the United States and in many foreign countries. The use of lime and Polystream2 for predator control was also developed at the Milford laboratory. Unfortunately, because of the current feelings about dumping chemicals in the water, the license for using Polystream has not been renewed.
In 1968, the American Cyanamid Company of Stamford, Conn., developed a report entitled, "New Engineering Approaches for the Production of Connecticut Oysters." They attempted, through a search of published literature relating to oysters, to develop an oyster factory. The general conclusion vvas that more research was needed (Calbo et al., 1968).
In New York, over 24 million pounds of oyster meats were landed in 1911. Since then production has steadily declined and reached an all-time low in 1967 of only 101,000 pounds. From 1968 to 1970, production has risen slightly to 534,000 pounds in 1970. New York like Connecticut has faced seed shortages. Three interesting developments have taken place in recent years in an attempt to alleviate this problem. At Fisher's Island, N.Y., seed oysters are being caught on scallop shells suspended from rafts in a 23-acre brackish water pond (Matthiessen, 1970a). In 1969, lSO rafts were mooredin the pond end roughly 68,000 strings were suspended. This year approximately 100,000 strings were used. In 7 yr of operation, only once was there a set failure. A portion of the shells bearing the oyster spat are stripped from the strings, loaded upon oyster boats, and planted upon private grounds in Long Island Sound. The remainder of the shells are transported to Massachusetts and suspended from the iron-pipe rack described earlier in the talk.
Second is the development of commercial shellfish hatcheries in the Long Island Sound area. One of the largest is operated by the Long Island Oyster Farms, Inc., in cooperation with the Long Island Lighting Company. The hatchery is utilizing a 4-acre pond which receives warm-water discharge from a fossil-fuel power plant. The young trayed oysters are placed in the pond for various periods of time before being planted on the bottom in the natural waters of the Sound. Because of the quicker growth rates in the heated pond, the oysters reach market size in a year or so sooner. A marine museum adjacent to the hatchery has been constructed for the viewing public.
Third is the New York State Department of Environmental Conservation project supported by federal funds (PL 88-309) to produce seed oysters in a natural pond in East Hampton, Long Island. To date, little success has been obtained in their attempts to catch seed on shells suspended from rafts or placed on the bottom.
The leading area of oyster production in the New Jersey-Delaware area is Delaware Bay. The once productive oyster beds in the Bay have been devastated by increasing pollution, freshwater abatement, increased predation problems, and, most recently, by massive mortalities from the disease, "MSX" (Minchinia nelsoni). Landings in 1970 totalled only 869,000 pounds. In 1950, the two states produced over 9 million pounds of oyster meats. The bay can be divided into two areas--the upper seed beds and the lower leased growing grounds. Shells are planted on the seed beds and later transplanted by the private planters to their leased bottoms. Following the heavy mortalities in 1957 and 1958, New Jersey initiated a large shell planting program to rehabilitate the oyster industry. Recently, heavy oyster sets on these shells suggests that the oyster industry may recover.
Both Rutgers University and the University of Delaware have been investigating disease resistance of oysters to MSX. Also, at the University of Delaware, extensive studies on the feasibility of semiclosed and closed systems for culturing oysters are now underway. This aspect of research is supported under the Sea Grant Program described earlier by Robert D. Wildman.
Chesapeake Bay is one of the leading oyster producing areas of the world. In l880, nearly 125 million pounds of meats were harvested from the Bay. In 1970, production was just under 35 million pounds or about one-half of the total U.S. production for that year. Yet, methods of oyster culture are extremely primitive with little or no change in either culturing or harvesting methods since the turn of the century.
In Maryland, for example, the majority of oysters harvested come from public bars. The tools used to harvest these oysters include hand tongs, patent tongs, and dredges pulled by boats under sail. Management consists mainly of planting up to 5 million bushels of shells for catching seed oysters and improving or enlarging public oyster bars. Following setting, the seed is replanted on public oyster bars where it remains until harvested by oystermen, 3 or 4 yr later.
There have been several attempts in recent years to demonstrate new methods of oyster culture that may be applied in Chesapeake Bay. These include hatchery systems, raft production of seed oysters, and culture of oysters to market size using offbottom techniques. Two commercial shellfish hatcheries have been built, one at Urbanna, Va., and the other on West River in Maryland. Both are producing cultchless oysters. Unfortunately these single oysters are very vulnerable to predators and the handling of the juveniles is a formidable problem (Matthiessen, 1970b). The former company is attempting to grow them to market size while the latter is selling the small spat to private growers. There are also two research agencies, Virginia Institute of Marine Science (Andrews and Mason, 1969) and the Chesapeake Biological Laboratory (Hidu, 1971; Hidu et al., 19693, working on hatchery techniques.
Two agencies, the Maryland Department of Natural Resources (Otto, 1969) and the National Marine Fisheries Service (Straw, 1970), have been studying raft production of seed oysters. Shells, either on strings or in chicken-wire bags, are suspended from rafts. Excellent sets are being obtained using the off-bottom techniques, but to date it has not been adapted commercially in Chesapeake Bay.
The National Marine Fisheries Service has also been studying the off-bottom culture of oysters (Straw, 1969, 1970, 1971). Methods being tested include raft, longline, and rigid-structure. Strings of spat-laden shells are suspended from each floating device and maintained in suspension until the oysters reach market size--about 21/2 yr from time of set. It is estimated that 11.9 tons of oyster meats per acre per year could be produced using off-bottom techniques.
In Virginia the majority of oysters are grown on private leases. Power dredging is the common method used for harvesting although hand tonging is also practiced. The majority of seed for the private bed cultivation comes from the James River. Unfortunately, in the late 1950's and early 1960's, heavy mortalities from MSX occurred among the oysters in the high salinity waters which included the spawning stocks for James River seed. Since then little or no setting has occurred in the James River.
The Virginia Institute of Marine Science has been working on developing disease resistant stocks using hatchery techniques. In addition, spat collecting shells are being planted in Great Wicomico, Piankatank, and other rivers (Bailey and Biggs, 1968). It is hoped that through the development of disease resistant stocks and managing around the disease, the oyster industry of Virginia can come back to productive levels.
The total production for the three south Atlantic states--North Carolina, South Carolina, and Georgia--was estimated to be 1.4 million pounds in 1970. Methods of culture in these three states are primitive, harvesting by hand is not uncommon. Little attempt has been made, until recently, to investigate new aquaculture techniques. In North Carolina, a seed collecting project was undertaken under the federal aid PL 88-309 program. Several varieties of cultch were tested. Because of heavy fouling, the cultch was lifted out of the water periodically. Using the airing technique, good quantities of seed and commercial size oysters were produced, but because of the excessive expense involved in the methods tested, it did not appear commercially feasible (Marshall, 1969).
The Coastal Zone Resources Corporation is attempting to grow oysters caught on passenger car tire beads (David Adams, pers. comm.). Eighty tons of eight bead configurations (about 14,000) have been planted in an area where oysters have the reputation for high quality and rapid growth. Each configuration is anticipated to yield about one-half bushel of oysters in 30 mo.
Beginning in 1944, extensive studies were conducted in South Carolina on the cultivation of oysters in ponds. Initially (1944-45), excellent results were obtained and marketable single oysters were produced in 2 yr. In 1950, drought conditions developed and salinities in the ponds rose. A sudden mass mortality among pond held oysters developed probably by Dermocystidium. It was concluded that as long as wild oysters are available to the industry, it is unlikely that pond culture will be economically practicable (Lunz, 1956).
In Georgia, two members of the Japanese panel, Atsushi Furukawa and Hisashi Kan-no, assisted in an attempt to develop off-bottom oyster culture techniques. Many problems were encountered including fouling, heavy siltation, erosion, and retardation of growth. It was felt that because of the current low price of oysters, off-bottom culture did not appear commercially feasible in Georgia at the present time (Lipton, 1968).
In 1970, Florida produced about 3.8 million pounds of oyster meats. The majority of oysters comes from the west coast of Florida. Oysters are harvested from public reefs either by tongs or picked by hand, with dredging allowed on leased beds. The future of the Florida oyster industry lies in the cultivarion of the private leases (Ingleand Whitfield, 1962)
The Florida Department of Natural Resources has several research projects related to oyster aquaculture (Florida Department of Natural Resources, 1970)--one is oyster nutrition and the other is oyster reef modification. Some success has been obtained in fattening oysters with finely ground cornmeal. These studies are continuing in conjuncion with learning optimal conditions (temperature, salinity, and other parameters) for fattening oysters.
Florida is presently studying the modification of natural reefs to improve their oyster production. Artificial gaps are being cut in the reefs. Oysters planted in these cut-out areas have shown excellent growth. Florida, through federal aid PL 88-309, is also constructing artificial oyster reefs using oyster shells and limestone slag. Some excellent sets have been obtained on the planted cultch.
One commercial company at Cedar Key, Fla., is attempting to grow strings of oysters from rigid structures (Robinson, 1971). Some problems have occurred resulting from the oysters falling off the strings. To solve this problem, portable racks have been built with bottoms to catch the oysters that fall off.
Similar to studies in North Carolina, attempts are being made to catch and grow oysters on tire beads at Cedar Keys, Fla. In this case the tire beads and configuration have been patented. It is not known if the operation is successful.
The oyster industry of Alabama is based upon natural repopulations of public reefs which include about 3,064 acres (May, 1971). In addition, there are approximately 2,000 acres of private bottoms, but they yield only 12% of Alabama's total oyster production (annual average from 1948 to 1968 was l.2 million pounds of meats). Lack of seed has kept private production down. All of the oysters from public reefs are harvested with hand tongs; however, harvesting from private beds can be accomplished with dredges.
Very little attempt has been made to try to modernize the Alabama oyster industry. May (1969) investigated the feasibility of off-bottom oyster culture. Both rack and raft methods were tested. Although excellent growth was obtained, he found the off-bottom culture was not economically feasible because of high production costs and low market value. The Alabama Marine Resources Laboratory at Dauphin Island constructed a 1/4-acre tidal pond to study the commercial rearing of oysters. In 1968, oysters were placed in the pond and after 12 mo the oysters had increased in height from 18 mm to 101 mm. Ninety-one percent were legal size after 81/2 mo of growth. It is not known if studies were continued.
The entire Mississippi oyster production comes from public reefs (about 3,000 acres), there are no private leases (Maghan, 1967). Annual production fluctuates considerably because of adverse weather conditions, leveeing of the Mississippi River, predators, and disease. As an example of these fluctuations, production in 1968 was 3.8 million pounds of meats while in 1970 only 547,000 pounds were landed. Except for extensive plantings of shells and seed oysters, there has been little attempt to modernize the oyster industry of Mississippi.
In 1970, Louisiana produced 8.1 million pounds of oyster meats, second in the nation to Maryland. Roughly 70-80% of the oysters are canned (Matthiessen, 1970b). Louisiana has a well-managed industry based on privately owned orleased bottoms, approximately 83,000 acres, plus state-owned areas (450,000 acres) set aside as a source of seed oysters (St. Amant, 1964). Growers are allowed to gather wild seed for planting on their leased grounds. All oysters are grown on the bottom and no attempt has been made to try off-bottom techniques.
The Louisiana Marine Laboratory on Grand Terre Island has several projects (federal aid PL 88-309) related to oyster culture. These studies include the reestablishment of historical seed grounds and control of the Southern oyster drill, Thais haemostoma. Both projects are still in progress so final results are not available.
At Grand Terre Island, 16 1/4-acre ponds were constructed on existing marsh floor. The levees were enclosed by two asbestos bulkheads that were supported by creosote posts and tied together by galvanized steel rods. Besides oysters, brown and white shrimp plus selected fishes are being cultured in these ponds. Preliminary results with oysters were not promising when high water temperatures resulted in excessive mortalities (Matthiessen, 1970b).
In 1970, 4.6 million pounds of oyster meats were harvested from Texas. The center of production is Galveston Bay. Harvesting has been confined almost entirely to the 22,000 acres of natural reefs (Hofstetter, 1959), although there are some 3,000 acres of leased bottom. Lack of good bottom for leasing has been a deterrent to oyster cultivation.
Considerable interest has developed recently in the pond culture of oysters (More and Elam, 1970). At Palacios, Texas, the Parks and Wildlife Department has built 21 artificial ponds ranging in size from a quarter of an acre to 4 acres. Studies on disease resistance to the fungal parasite Labyrinthomixa sp. are being conducted. Attempts are also being made to relate water depth and type of pond construction to oyster growth and survival.
The hard clam, Mercenaria mercenaria, (also called quahog, quohog, and quahaug) is distributed along the Atlantic coast and the Gulf of Mexico. They reached their peak of production in 1950 when 21 million pounds were harvested. Production then dropped until 1955 when 14.2 million pounds were landed. Since then, production has remained fairly stable fluctuating between 13.3 and 15.8 million pounds, and in 1970 approximately 15.4 million pounds of meats were produced. New York is the leading producer (7.9 million pounds) while five states--Virginia, New Jersey, New York, Massachusetts, and Rhode Island--accounted for 91% of the total U.S. landings. The entire fishery comes from wild stocks although some attempts are being made to utilize hatchery stocks.
In New York the center of the resource is on the southern shore of Long Island in the sheltered bays such as Great South Bay. Many types of gear have been used to harvest clams. These include tongs, rakes, dredges, by hand, hoes, and grabs. In 1967, New York harvesting was divided among three types of gear--dredges, 2.6 million pounds; tongs, 2.5 million pounds; and rakes, 1.9 million pounds. Introduced into this industry in recent years was the hydraulic escalator dredge which harvests clams with surprisingly little damage (Engle, 1970) to either the clams or the clam beds. This gear is also used in Chincoteague Bay, Md.
The hard clam fishery appears to be in excellent condition although there is some concern over the increasing threat of pollution. In New York there are an estimated 450,000 acres of potential shellfish producing bottoms of which 156,892 acres or approximately 35% of the total are uncertified. Considerable effort has been devoted by the New York Conservation Department to develop depuration techniques. A PL 88-309 project entitled, "Operation of a depuration plant for hard clams (Mercenaria mercenaria)," was completed in 1969 (MacMillan and Redman, 1971). Results of the study, using a "pilot" scale depuration system, indicated that the depuration of hard clams is feasible, both economically and bacteriologically when such shellfish are harvested from restricted growing areas (Median Coliform MPN range: 70-700). The successful operation is greatly enhanced utilizing seawater obtained from a saltwater well. It was estimated that hard clams could be depurated at a cost of $1.76 per bushel.
The most intensive efforts towards propagation on a commercial scale have been made on Cape Cod and Long Island (Miller et al., 1970). Clams are artificially spawned to setting using methods described by Loosanoff and Davis (1963). The seed clams are held in especially designed hatcheries and then transplanted to controlled growing areas. Heavy losses from predation have been a serious problem following planting on the growing grounds. To solve this problem the Virginia Institute of Marine Science has developed the use of aggregates on the bottom to protect the seed clams from predators (Castagna, 1970). Three types of aggregates were found successful: 1) crushed oyster shell, 2) crushed stone, and 3) stream bed gravel (pea gravel).
An average of more than 80% of the seed clams planted with aggregates survived compared to 16-30% survival on plots without any aggregates. Clams should be at least match-head size before planting and should be scattered over the aggregate at a rate of about 25-50 per square foot.
One of the largest clam hatcheries is located in North Carolina (Tyler, 1970). Since early 1970, Coastal Zone Resources Corporation has been engaged in producing hard clam sets using hatchery techniques (David A. Adams, pers. comm.). Approximately 4 million clam larvae are produced each week. Metamorphosis occurs in about 2 wk. They are then placed in shallow 2 ft x 4 ft plywood trays mounted vertically in banks of 10 trays each. Here the set stays for an additional 8 wk. When the clams are about 10 wk old, they are transferred into running seawater concrete raceways. Under ideal conditions. the seed clams measure 1-2 cm at about 14 wk of age. When the clams reach 2.5 cm, they are either sold as seed clams or planted by the corporation on nearby mud flats to grow to commercial size.
The bay scallop, Aequipecten irradians, ranges from Maine to the Gulf of Mexico (Belding, 1910). Principal areas of abundance are the southern New England states; Peconic Bay, Long Island, N.Y.; und the bay and inlets of North Carolina (Gutsell, 1931). In 1970, approximately 865,000 pounds, valued at 1.2 million dollars (dockside value $1.39/lb) were landed in two states, New York and Massachusetts. The bay scallop rarely lives beyond 2 yr (Merrill and Tubiash, 1970). Because of its short life span and high value, this species is highly suitable for aquaculture. Yet, very little attempt has been made to farm this animal.
Wells (New York Conservation Commission, 1927) was one of the first to artificially rear bay scallops. Since then others including Loosanoff and Davis (1963) and Castagna and Duggan (1971) have successfully spawned and reared the larvae to setting stages.
Several programs are presently underway in an attempt to farm the bay scallop. Under a federal aid project PL 88-309, the State of New York has just begun studies on the growth of scallops during the fall, winter, and spring in heated waters. Scallops will be subjected to 40°, 50°, 60°, and 70°F respectively, and periodic growth measurements will be taken. It is also planned to place scallops in cages placed in the effluent discharge from LILCO Electric Power Station at Port Jefferson, N.Y.
Under a Sea Grant Program described earlier by Robert D. Wildman, the Virginia Institute of Marine Science is rearing bay scallops to market size under controlled conditions (Castagna and Duggan, 1971). Scallops collected from Virginia and North Carolina were conditioned and spawned in the luboratory. Following setting. juveniles were held in plastic trays in the laboratory for 1 wk. They were then moved to outdoor tanks with flowing unfiltered seawater. They remained there until they were 2 mm in width. The scallops were then moved to natural waters and placed in plastic coated wooden floats. They reached an average minimum market size of 50 mm in 12-13 mo. The authors felt that bay scallops appeared amenable to mariculture.
I have briefly described the past and present status of molluscan aquaculture along the Atlantic and Gulf coasts. The next question is where do we go from here? In your country (Japan), we realize that molluscan aquaculture is much further advanced than in the United States. One reason, of course, is your basic protein diet consists of aquatic products while Americans eat basically land-grown products (beef, chicken, etc.). To supply the Japanese people with aquatic products, you utilize your inland waters considerably different than we do in the United States. For example, almost all of your oysters are grown off-bottom in order to produce the maximum numbers per unit of area. You have set priorities on the use of your waters--first, for food production; second, for navigation; and third, for recreation. In the United States the waters are used mainly for navigation and recreation. The use of our waters for food production is on a very low scale. For the United States to develop molluscan aquaculture in the future, we will have to change our philosophy on water usage. This is going to be extremely difficult and maybe impossible.
A second point is that the development of molluscan aquaculture in the United States will only succeed if it is done profitably. Already many companies which entered aquaculture have lost money and have quickly left the business. For this reason the development of aquaculture in the United States must depend initially on animals that have a high market value. These animals must feed at a low trophic level. Even using high valued crops, it is a question whether or not a profit can be made because of high costs of labor, materials, private leases, etc.
The third problem is that legal rights to conduct aquaculture must be defined. Only recently laws were passed in Florida which made mariculture legal (Davis and Shields, 1971). Similarily, in Maryland, until this year, it was illegal to grow oysters off-bottom. These are exceptions--in most states along the Atlantic and Gulf coasts, there are no laws which protect the aquaculture investor or even allows aquaculture to be conducted.
The threat of pollution will hinder the development of molluscan aquaculture in the United States. No one wants to invest a great amount of capital, raise a product to market size, and then find that he cannot sell his product because it comes from polluted waters. One answer to this problem is to avoid the use of waterways and to culture the animals in a closed system similar to methods used to grow chickens. Unfortunately, our technology has not developed far enough to make this possible. Sea Grant Programs, like the one at the University of Delaware, are working towards this goal. It is the hope of all of us at this Symposium, that aquaculture will develop to the level of agriculture. Your country has made great strides towards this goal. Through our state, university, and govetmental agencies, we in the United States are learning more every day about aquaculture techniques. It is hopeful that this knowledge can be applied in the future. It is our goal that someday, through the development of aquaculture techniques, we may produce enough protein to help feed our increasing world population. IT MAY BE OUR ONLY SALVATION!!!
ANDREWS, J. D., and L. W. MASON.
1Middle Atlantic Coastal Fisheries Center. National Marine Fisheries Service. NOAA. Oxford. MD 21654.
2 A polychlorobenzene product produced by Hooker Chemical Corp., Niagara Falls, New York. Polystream is a registered trademark. (Reference to trade names does not imply endorsement by the National Marine Fisheries Service, NOAA.)