Trout

Stamford J A, Pali] P, Davidson C and Trout S J 1995 Fast oyolio voltammetry neurotransmitter measurement in real time and real spaoe Bioelectrochem. Bioenerg. 38 289... 

Fishes in the family Salmonidae (trout and salmon) are in high demand, with the interest in salmon being greatest in developed nations. Salmon, mostiy Atiantic salmon, are produced in Canada, Chile, Norway, New Zealand, Scotiand, and the United States. Fishes in the family Cichhdae which includes several cultured species of tilapia, are reared primarily in the tropics, but have been widely introduced throughout both the developed and developing world. 

Fig. 3. A commercial trot faciUty in Idaho, U.S. Linear raceways are commonly used for the production of trout from fry to either release or market and for...

Salmon, steelhead trout, and a variety of marine fishes are currentiy being reared in net-pens (Fig. 5). The typical salmon net-pen is several meters on each side and may be as much as 10 m deep (1). Smaller units, called cages, are sometimes used by freshwater culturists. Cages tend to have volumes of no more than a few cubic meters. 

Table 4. General Water Quality Requirements for Trout and Warmwater Aquatic Animals in Fresh Water ...

Requirements for energy, protein, carbohydrates, Hpids, vitamins and minerals have been determined for the species commonly cultured (9). As a rule of thumb, trout and salmon diets will, if consumed, support growth and survival in virtually any aquaculture species. Such diets often serve as the control against which experimental diets are compared. 

Species such as carp, salmon, trout, channel catfish, and tilapia have been bred for many generations in captivity though they usually differ httle in appearance or genetically from their wild counterparts. A few exceptions exist, such as the leather carp, a common carp strain selectively bred to produce only one row of scales, and the Donaldson trout, a strain of rainbow trout developed over numerous generations to grow more rapidly to larger size and... 

Unlike catfish, tilapia, trout and salmon, that produce several hundred to several thousand eggs per female, many marine species produce large numbers of very small eggs. Hundreds of thousands to millions of eggs are produced by such species as haUbut, flounders, red dmm, striped bass, and shrimp. Catfish, salmon, and trout spawn once a year, while tilapia and some marine species spawn repeatedly if the proper environmental conditions are maintained (1). Red dmm, for example, spawn every few days for periods of several months when light and temperature and properly controlled (10). 

Pish silage prepared by autolysis of rainbow trout viscera waste was investigated as a substrate for the plastein reaction using pepsin (pH 5.0), papain (pH 6—7), and chymotrypsin (pH 8.0) at 37°C for 24 h (152). Precipitation with ethanol was the preferred recovery method. Concentration of the protein hydrolysate by open-pan evaporation at 60°C gave equivalent yields and color of the final plastein to those of the freeze-dried hydrolysate. 

AH of the propylene glycols are considered to be practically nontoxic to fish on an acute basis (LC q < 100 mg/L) and practically nontoxic to aquatic invertebrates, also on an acute basis. Acute marine toxicology testing (38) on propylene glycol showed that the 96-h LC q for fathead minnows was 54,900 mg/L and the 48-h LC q for Daphnia magna was 34,400 mg/L. A 24-h NOEL of 50,000 mg/L was also observed for fingerling trout. Similar results were observed for guppies and rainbow trout (39). 

The compound is relatively nontoxic. Because many golf courses and recreational grassy areas abut lakes and ponds that are used for fishing, the environmental toxicity data are important. The LC q for trout (96 h) is 80 mg/L for bluegiU. (96 h), 36 mg/L and for Daphnia, 64 mg/L. 

The mode of action has not yet been elucidated but the manufacturer states that it probably behaves like the herbicide triflurolin and its congeners. These materials inhibit cell division by binding to tubuHn thereby internipting micro-tubule development. This, in turn, stops spindle fiber formation essential to mitosis and cell division. Experiments with C-labeled Prime+ show that it is acutely toxic to fish with estimated LC q (96 h) of less than 100 ppb for rainbow trout and bluegiU. sunfish. However, channel catfish did not exhibit any toxic response at the maximum attainable water concentration (10). 

DDT is highly toxic to fish (LC q for trout and blue gill, 0.002—0.008 ppm), and it is only moderately toxic to birds (oral LD q mallard 1300 and pheasant >2240 mg/kg). However, widespread bird kills have resulted from bioconcentration of DDT through food chains, ie, from fish or earthworms. A significant environmental problem has resulted from the specific effects of DDE on eggshell formation in raptorial birds where accumulation has caused decreases in shell thickness of 10—15%, resulting in widespread breakage. 

Mcute Toxicity of Mmmonium Molybdate andMolybdic Trioxide to Bluegill (Eepomis macrochirus) and Kainbow Trout (Salmogairdneri) Bioassay Report submitted to AMAX Inc., Bionomics, Inc., Wareham, Mass., Jan. 1975. 

Oxygen, when introduced into fish-farming ponds and pools, particularly trout pools, enables these fish to increase their food intake and hence grow more rapidly (see Aquaculture chemicals). Fermentation operations are accelerated by sparging with oxygen (see Aeration,biotechnology Ferl ntation). 

Environmental Impact of Ambient Ozone. Ozone can be toxic to plants, animals, and fish. The lethal dose, LD q, for albino mice is 3.8 ppmv for a 4-h exposure (156) the 96-h LC q for striped bass, channel catfish, and rainbow trout is 80, 30, and 9.3 ppb, respectively. Small, natural, and anthropogenic atmospheric ozone concentrations can increase the weathering and aging of materials such as plastics, paint, textiles, and mbber. For example, mbber is degraded by reaction of ozone with carbon—carbon double bonds of the mbber polymer, requiring the addition of aromatic amines as ozone scavengers (see Antioxidants Antiozonants). An ozone decomposing polymer (noXon) has been developed that destroys ozone in air or water (157). 

The chronic aquatic effects which relate silver speciation to adverse environmental effects were studied on rainbow trout eggs and fry. The maximum acceptable toxicant concentration (MATC) for silver nitrate, as total silver, was reported to be 90—170 ng/L (43). Using fathead minnow eggs and fry, the MATC, as total silver, for silver thiosulfate complexes was reported as 21—44 mg/L, and for silver sulfide as 11 mg/L, the maximum concentration tested (27). 

The cyclopropenoid fatty acids, malvaUc acid and stercuhc acid, exist in hexane-defatted meal at levels of 21—76 ppm (70). In rainbow trout, the cyclopropenoid acids cause cancer of the fiver either alone or by acting synergistically with aflatoxin B. However, similar effects in mammals or humans have not been demonstrated (63). 

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