Massachusetts Aquaculture White Paper - Commercially Important Finfish

The following information on commercially important finfish is found in Boschung et al. (1983), Scott and Crossman (1973), Scarola (1973), Tomelleri and Eberle (1990), Clayton et al., Lee et al. (1983), and Page and Burr (1991).

Currently, there are eleven major fish species cultured in significant numbers in Massachusetts. They are the Atlantic salmon, bluegill, brook trout, brown trout, channel catfish, golden shiner, hybrid striped bass, koi, largemouth bass, rainbow trout, and tilapia. The American eel also has potential in the aquaculture industry. These species run the gamut from those native to the Commonwealth such as brook trout and Atlantic salmon to truly exotics such as the African tilapia. The reasons for culturing these species are as varied as the fish themselves. From recreational fishing to food to restoration efforts, aquaculture in the northeast is growing rapidly and shows promise for continuing expansion in the future. Following are summaries of life histories and environmental requirements for these species.

Atlantic Salmon

The distribution of Atlantic salmon (Salmo salar) includes the basin of the North Atlantic Ocean from the Arctic Circle to Portugal in the eastern Atlantic, from Iceland and southern Greenland, and from the Ungava region of northern Quebec south to the Connecticut River. Atlantic salmon are anadromous fish in that part of their life cycle occurs in saltwater and part in freshwater. Atlantic salmon were extirpated in Massachusetts due in part to overfishing, pollution, dam construction and habitat loss. As a result of a joint effort between the Massachusetts Department of Fisheries and Wildlife and other cooperating agencies to restore Atlantic salmon, they now occur in 9 of the state's 32 watersheds.

The life cycle of the Atlantic salmon begins when females deposit up to 8,000 eggs in redds (nests) constructed in the gravel substrate of clean, well oxygenated streams in October and November. The eggs hatch in the spring, where the sac-fry (or alevins) remain in the gravel until the yolk-sac has been completely absorbed. The young salmon (now referred to as parr) remain in the streams from one to three years. At this time, the juvenile salmon undergo physical changes which prepare them for their migration to the ocean. At this stage they are referred to as smolts. Salmon return to spawn after spending two winters at sea. They return primarily in May and June and attempt to reach the same streams they left as smolts. The summer months are generally spent in deep pools prior to spawning in the fall. They then return to the ocean in late fall or early spring. Parr and smolts in streams feed primarily on aquatic insect larvae. While at sea, Atlantic salmon eat crustaceans and fish. Adult salmon do not feed from the time they enter fresh water to spawn until they return to salt water in the late fall or spring.

Atlantic salmon are cultured extensively at state, federal and private facilities throughout the northeast for restoration efforts, recreational fishing opportunities and as a food fish. Under culture conditions, Atlantic salmon eggs should be incubated at 42° F. Upon hatching, the temperature should be dropped to 38° F until the sac fry begin to accept prepared food. At this point the temperature should be raised to 50° F then slowly increased to a final maintenance temperature of 60° F. The pH should be greater than 6 and dissolved oxygen levels should remain above 7 ppm.

American Eel

The Atlantic distribution of the American eel (Anguilla rostrata) includes the entire eastern seaboard of the United States, southeastern Canada, and the Gulf of Mexico. They are as far inland as the Great Lakes.

Although currently not popular as a food fish in the United States, American eels are considered a delicacy in European and Asian countries. Traditionally, fish were harvested from the wild at edible size but young eels have recently been captured and cultured to market size.

American eels are catadromous species, meaning that they spend their juvenile life in fresh water and migrate to the ocean to spawn. Adult eels move from rivers into the ocean in the fall, travelling to the southwest part of the North Atlantic, called the Sargasso Sea. After spawning, the adults die and the eel larvae travel on ocean currents back toward the mainland, feeding and growing along the way. The eel larvae undergo metamophosis from the leptocephalus larvae to a glass eel stage and finally, when pigment forms, the elver stage. The elvers reach stream mouths in the Spring and travel up the rivers.

Bluegill

The distribution of bluegills (Lepomis macrochirus) includes most of southern Canada and the United States east of the Rocky Mountains. It has been introduced throughout the United States and northern Mexico. As a result of early stocking as a forage fish, it is widely distributed in Massachusetts occurring in 30 of the state's 32 watersheds.

Bluegill prefer clear warm pools of streams, lakes and ponds usually inhabiting shallow, weedy waters. Bluegills generally travel in schools at depths from one to twenty feet. Their diet consists mainly of aquatic insects, but they will also consume small fish and eggs and aquatic vegetation. Bluegills spawn in spring and summer in shallow water. If water temperatures remain high, spawning may continue into early fall. As with other members of the sunfish family, the male excavates a shallow nest preferably on gravel substrate. Males then guard this nest while tempting females to lay eggs. A large female may produce as many as 27,000 eggs spread out over several nests. The fry are generally guarded by the male for a short period prior to their dispersal.

Bluegill are the most common sunfish and a highly prized game fish throughout the United States. They are cultured in private facilities mainly to provide recreational fishing on site or for stocking as a forage fish in smaller ponds with species such as largemouth bass. Under culture conditions, optimal temperatures for embryo development are 72-81° F while 81° F is optimal for growth of adults. The pH should remain between 6.5 and 8.5 for all life stages and although dissolved oxygen levels of less than 1.0 ppm may be tolerated for short periods, a level of greater than 5.0 ppm should be maintained.

Brook Trout

The distribution of brook trout (Salvelinus fontinalis) includes northeastern North America from the Atlantic seaboard south to Cape Cod, the Appalachian Mountains southward to Georgia, west in the upper Mississippi and Great Lakes drainage to Minnesota and North to Hudson Bay. Their natural range has been greatly expanded through artificial propagation. In Massachusetts, brook trout can be found in 31 of 32 watersheds.

Brook trout occur in a wide variety of habitats from small streams to large lakes. Their only true requirements are a year-round supply of cold, well oxygenated water and areas of gravel on which to spawn. As water temperatures rise, stream dwelling brook trout may move downstream to larger bodies of water. Brook trout diet consists of a wide range of aquatic and terrestrial insect and larvae with occasional plant material. Brook trout spawn in late summer or autumn generally in the shallow headwaters of streams or along gravel bars of lakes. Females clear away debris by rapidly fanning the substrate with their tail. Upon completion of spawning, the female covers the eggs with gravel in much the same way she cleared the redd. The number of eggs produced by a female is dependent on body length but may be as high as 5,000. The eggs develop through the winter hatching in about 140 days.

Brook trout are raised in large quantities by state facilities for stocking into public lakes and streams. They are also cultured in private facilities for both recreational fishing on site and for stocking into private ponds. Additionally they are utilized by the supermarket and restaurant trade as a food fish. Under culture conditions, brook trout should be maintained at a temperature of about 59° F for optimal growth. The pH should remain close to neutral with an acceptable range of 6.7 to 8.2. As with most salmonid species, dissolved oxygen levels should remain above 5.0 ppm.

Brown Trout

The distribution of brown trout (Salmo trutta) includes Iceland, the British Isles and the Eurasian mainland from Cape Kanin to the Aral Sea and Afghanistan westward throughout Europe. Brown trout have been widely introduced into many parts of the world. As a result of stocking beginning in the late 1800's, they are widely distributed throughout Massachusetts occurring in 25 of 32 watersheds. The habitat requirements are essentially the same as for brook trout, however brown trout are slightly more tolerant of higher water temperatures. They have been found to survive in waters as high as 80° F. They are frequently found in the slower, deeper pools of streams where they coexists with brook trout. The diet of young brown trout consists of a wide variety of aquatic and terrestrial insects and their larvae as well as fish and other vertebrates. Larger fish feed mainly during the twilight and nighttime hours with fish and crayfish playing a much more important role in their diet. Brown trout spawn in late autumn to early winter as water temperatures approach 45° F. Spawning habitat is essentially the same as for brook trout, namely shallow gravelly headwaters. Generally brook trout have completed spawning before brown trout begin, however. The number of eggs produced by a single female is dependent on body size but ranges from 2,000 to 6,000. The eggs develop over winter in the gravel and hatch in the spring.

Brown trout are cultured in large numbers in state facilities for stocking into public waters. Culture also occurs in private facilities mainly for recreational fishing on site and for stocking into private ponds. Under culture conditions, the optimal temperature range for embryo development is 41 to 55° F. For adults, a temperature range of 54 to 66° F should be maintained. The pH should remain between 6.8 and 7.8 while dissolved oxygen levels should be above 5.0 ppm.

Channel Catfish

The distribution of channel catfish (Ictalurus punctatus) extends from the St. Lawrence and its tributaries in Quebec, south, west of the Appalachian Mountains, to southern Georgia and Central Florida, west through the Gulf states to eastern Texas and northern Mexico, northwest through the eastern part of the states from New Mexico to Montana, east to the Red River System in Manitoba, southwestern Ontario, southern Minnesota, Wisconsin and Michigan and through Ontario and Quebec at the level of Lake Nipissing. A limited stocking program has introduced channel catfish into 14 of the state's 32 watersheds.

Preferred habitat for channel catfish includes lakes and larger rivers in slow to moderate current over sand, rubble or gravel bottoms. They are most active at night generally seeking shelter in bottom structure during the day. Young channel catfish feed primarily on aquatic insects while adults eat a wide variety of both plant and animal matter. Spawning behavior begins as water temperatures approach 75° F. Males excavate the nest and aerate and clean the eggs. A single female may produce up to 30,000 eggs. Eggs hatch in 5-10 days depending on water temperature. Males may guard the young prior to dispersal.

Channel catfish are one of the most important freshwater species cultured in the United States, particularly in the south. They are currently cultured in private facilities in Massachusetts for recreational fishing on site and for stocking into private ponds. Under culture conditions, channel catfish may reproduce naturally in culture ponds or be spawned and reared in captivity with the resultant fingerlings released into ponds for grow-out. Optimal temperature for maximum growth of channel catfish is 85° F. The pH should remain at neutral (7.0) while dissolved oxygen levels should be maintained above 5.0 ppm.

Golden Shiner

The distribution of the golden shiner (Notemigonus crysoleucas) includes virtually all of the United States and southern Canada east of the Rocky Mountains. Additionally, it occurs west to the Dakotas and Texas. In Massachusetts, it is widely distributed occurring in all but one of the 32 watersheds.

The preferred habitat of golden shiners includes shallow, weedy, quiet regions of lakes and ponds where they move in large schools. Wherever they occur, they are a primary food source for black bass, chain pickerel and other game fish. Golden shiners are midwater and surface feeders where they consume a wide variety of plant and animal matter. The diet is consistent from young to adult and includes, among many other items, aquatic and terrestrial insects and their larvae. Filamentous algae becomes important in late summer. Spawning is initiated as water temperatures approach 68° F. It may be protracted and continue throughout the summer. The adhesive eggs are scattered over beds of submergent vegetation in shallow, quiet areas of lakes and streams. A single female may produce up to 200,000 eggs and may spawn more than once during the breeding season.

Golden shiners are currently the most important species to the Massachusetts bait fish industry. Culture of golden shiners in Massachusetts consists primarily of importation of a variety of sizes (mainly from Arkansas) which are maintained on site for resale as a bait fish.

Hybrid Striped Bass

Hybrid striped bass are a cross between striped bass (Morone saxatilis) and white bass (Morone chrysops). Pure strain white bass and striped bass are currently not cultured in Massachusetts. Although a population of hybrids is not capable of self sustaining, it may backcross with either striped bass or white bass. Life history information for striped bass and white bass is presented here in reference to the culture of hybrid striped bass in Massachusetts.

Striped bass are anadromous fish associated with coastal streams when in freshwater. They occur along the Atlantic coast from the St. Lawrence River to the St. Johns River, Florida as well as the Gulf of Mexico and tributaries in Alabama, Mississippi and Louisiana. Their distribution in Massachusetts is limited to eight of 32 watersheds associated with large coastal river systems.

As with the Atlantic salmon, striped bass spend the majority of their life cycle in saltwater, returning to freshwater streams to spawn. With the exception of migrations, striped bass are found near shore generally in salt and brackish waters. Striped bass appear in Massachusetts coastal waters in late spring to early summer. During this time, they may enter estuarine and freshwater systems. In the fall, striped bass migrate south to overwintering grounds, however, some individuals may overwinter in Massachusetts in freshwater rivers. During these migrations, they represent one of the most important recreational fish species in Massachusetts. When in coastal waters, striped bass are voracious feeders foraging on fish, crustaceans and polychaetes. While in freshwater, their diet consists mainly of small fish such as herring, menhaden, shad and alewives. Striped bass spawn in large, rapidly flowing rivers in the spring with a peak occurring at about 18° F. Large, semibuoyant eggs are broadcast and drift with the current. A single female may produce up to a million eggs. The eggs hatch within two to three days depending on water temperature. Juvenile striped bass may remain in freshwater for up to two years before migrating to saltwater.

The distribution of white bass includes the St. Lawrence River west through the Great Lakes states from New York to Minnesota, west to South Dakota and south in the Ohio and Mississippi valleys to the Gulf of Mexico. Its natural range has been greatly enhanced as a result of stocking. Currently, there are no populations of white bass in any watersheds in Massachusetts.

White bass are generally found in schools in the upper water column of large streams, lakes and reservoirs. They prefer clear water and tend to be found over sand, rock or gravel bottoms. The diet of young white bass consists of small crustaceans, insect larvae and fish. Fish make up the bulk of the diet for adults. Prey items are located visually, thus their tendency to be found in clear waters. Spawning commences in the spring as water temperatures approach 55-60° F. At this time, large schools begin to make inshore movements to shoals and estuaries. Adhesive eggs are fertilized as they are broadcast into the substrate. Here they attach to vegetation, gravel, boulders etc. A single female may produce up to 500,000 eggs. At spawning temperatures, eggs generally hatch within 46 hours.

Hybrid striped bass are cultured in private facilities mainly for supply to the restaurant and supermarket trade as a food fish. Currently, hybrid striped bass culture in Massachusetts begins with fingerlings imported from out of state. Under hatchery conditions, these fingerlings are reared at 79° F in hard water. The pH should be maintained at between 6.5 and 8.5 and the dissolved oxygen level should remain above 6.0 ppm. There is also some limited grow-out of these hybrids occurring in culture ponds.

Koi

Koi are a color variant of common carp (Cyprinus carpio). The distribution of carp includes temperate portions of Asia and Europe. It was widely introduced into North America by the U.S. Fish Commission in the mid 1800's. They occur in 16 of 32 watersheds in Massachusetts scattered throughout the state.

Carp do best in warm, shallow impoundments with abundant vegetation. They are tolerant of extremes in temperature and low dissolved oxygen. In addition, they fare well in areas of poor water quality. Carp feed on a wide variety of plant and animal matter. They are capable of taking food items floating at the surface, but generally root in soft substrate and pick out food items from the resultant cloud of silt. Spawning commences in early spring as water temperatures approach 63° F. Large congregations move to shallow, weedy waters then break up into smaller groups of several males to one female. A single female may produce up to 2,000,000 adhesive eggs which are broadcast and adhere to submerged vegetation. Eggs hatch within 3-6 days depending on water temperature.

Koi are cultured in private facilities for sale as an ornamental fish for stocking into private ponds of for the aquarium trade. Under culture conditions, optimal growth for young koi is between 81 and 93° F, while 68 to 82° F is optimal for adults. The pH should remain between 6.8 and 7.5, and while koi are capable of surviving in warm waters with low oxygen, dissolved oxygen levels should remain above 5.0 ppm for good growth.

Largemouth bass

The native range of largemouth bass (Micropterus salmoides) includes the lower Great Lakes, the central part of the Mississippi River system south to the Gulf Coast, Florida and north on the Atlantic coast to Virginia. As a result of its popularity as a game fish, the largemouth bass may now be the most widely introduced of fish in North America. It occurs over virtually the entire Atlantic coast from Maine to Florida, west to Texas and northeastern Mexico, north through the eastern parts of the states from New Mexico to North Dakota and east across southern Canada to western New York. Additionally, it has been introduced throughout the UK, Europe, South Africa, Hong Kong, the Philippines and Brazil. Largemouth bass are widely distributed throughout Massachusetts occurring in all 32 watersheds.

Largemouth bass are predominantly found in shallow, small lakes and bays of larger lakes and in large, sluggish rivers. In all cases, they generally occur over soft substrates typically associated with structure. Largemouth bass feed from the surface, water column and bottom on a variety of food items. Young bass eat primarily aquatic insects with fish, mollusks and crayfish playing an important role in the diets of adults. Largemouth bass spawn from late spring through mid-summer as water temperatures approach 60° F. Males construct a 2-3 foot nest over gravel in shallow, protected areas which they defend vigorously. A single female may produce from 2,000 to 10,000 eggs and may spawn with several males on different nests. As with other sunfish species, the male defends the nest and fans the eggs to ensure they are well oxygenated. Eggs generally hatch within a week to ten days. The fry remain in a brood guarded by the male for several weeks prior to dispersal.

Largemouth bass are cultured at private facilities for recreational fishing on site and for stocking into private ponds. Under culture conditions, largemouth bass may be spawned and reared artificially or allowed to reproduce in culture ponds with the resultant young moved to other ponds for grow-out. Optimal temperature for growth of largemouth bass is between 75 and 86° F. Although largemouth bass may survive short exposures to pH as low as 4.0, for best growth, pH should remain between 6.5 and 8.5. As with pH, largemouth bass can survive brief exposure to low dissolved oxygen levels, optimal growth however, occurs at dissolved oxygen levels above 5.0 ppm.

Rainbow Trout

Rainbow trout (Oncorhynchus mykiss) originally occurred in the eastern Pacific Ocean and freshwater west of the Rocky Mountains from northwest Mexico to the Kuskokwim River, Alaska. As a result of introductions outside its range, rainbow trout are now found throughout North America. Additionally, sea-run forms, referred to as steelhead trout, migrate to saltwater then return to freshwater to spawn. They are widely distributed throughout Massachusetts occurring in 23 of 32 watersheds.

As with all trout, rainbow trout do best in cold, well oxygenated waters. As with brown trout, however, they are much more tolerant of warmer temperatures than brook trout. They are capable of surviving in waters as high as 85° F provided the water remains well aerated. They occur both in lakes and rivers with moderate flow and gravel substrate. Young fish are generally found in riffle sections of rivers and streams while older fish frequent quiet, deeper pools. Rainbow trout generally feed off the bottom foraging on virtually all aquatic insects and their larvae that occur in their habitats. Where they occur in lakes, fish can become a primary food item. Spawning commences in early spring as water temperatures approach 50° F. Spawning takes place in smaller tributaries of rivers or inlet and outlet streams of lakes and ponds. As with other trout, the female excavates a nest in gravel generally in a riffle above a pool. Eggs are broadcast into the nest then immediately covered with gravel by the female. Eggs numbers may be as high as 12,000 per female. Eggs hatch within two months depending on water temperature with the resulting alevins becoming free swimming within seven days.

Rainbow trout are cultured in large numbers at state facilities for stocking into public waters. Culture also occurs in private facilities for recreational fishing on-site, stocking into private ponds and as a food fish for the restaurant and supermarket trade. Culture conditions for rainbow trout are identical to those of brook trout. Temperature should be maintained at about 59° F for optimal growth. The pH should remain close to neutral with an acceptable range of 6.7 to 8.2. As with most salmonid species, dissolved oxygen levels should remain above 5.0 ppm.

Tilapia

Tilapia (Tilapia sp.), which includes about 80 different species, were originally found throughout the African continent. As a result of transplants, particularly in extreme southern United States, they are now found outside their native range. Due in part to their inability to survive at temperatures much below 50° F, they are not found in Massachusetts' waters.

Tilapia are generally found in warm, shallow, turbid waters of rivers and lakes. They are herbivores feeding mainly on plankton, filamentous algae, aquatic macrophytes and other vegetable matter. In the wild, tilapia spawn year round with females producing up to 1,200 eggs. There are two types of spawners, substrate or mouthbrooders, depending on the species. Substrate spawners, as the name implies, broadcast eggs into the substrate. With mouthbrooders, the female incubates the fertilized eggs and resultant fry in her mouth to guard them against predation. Eggs generally hatch within seven days.

Tilapia are cultured in private facilities for sale as a food fish to the restaurant and supermarket trade. Under culture conditions, broodstock are held on site and spawned to produce eggs. Mouthbrooders are generally used as broodstock due to their large fry clusters and successive breeding cycles. Under ideal conditions, females may spawn every seventeen days. The eggs and resultant fry are maintained at a temperature of 80 to 84° F. The pH is maintained at 7.5 to 7.8 while dissolved oxygen levels should remain at or above 8.0 ppm. Under these conditions, market sized fish (1/2 lbs.) can be obtained in about seven months.

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Published: September 1995