Brook trout survival

Our study concerned the potential for aluminum toxicity to brook trout (Salveiinus fontinalis) in acidified waters of the Adirondack Mountains of New York State. In this paper we present an analysis of field observations on brook trout survival in acidified Adirondack waters and comparative laboratory bioassay data for evaluation of aluminum effects on brook trout survival and growth. 

Studies of 30 to 60 days duration with three comparatively sensitive species of freshwater fishes demonstrated that concentrations of >1 and <3 pg Cd/L in water of low alkalinity caused reductions in growth, survival, and fecundity of brook trout (Salvelinusfontinalis), the most sensitive species tested (Table 1.3). Under conditions of increasing alkalinity, the maximum allowable cadmium concentration range for brook trout increased to >7 and <12 pg/L a similar case was made for the walleye (Stizostedion vitreum vitreum Table 1.3). 

McKim, J.M. and D.A. Benoit. 1971. Effects of long-term exposures to copper on survival, growth, and reproduction of brook trout (Salvelinus fontinalis). Jour. Fish. Res. Bd. Can. 28 655-662. 

The International Joint Commission of the United States and Canada recommend a water quality standard of 0.008 pg/L for the protection of freshwater aquatic life. This standard is based on the study by Mayer et al. (1975), who found that toxaphene at 0.039 pg/L in water caused a significant increase in mortality and a significant decrease in growth of surviving brook trout fry over a 90-day period. The standard of 0.008 pg/L is obtained by applying an uncertainty value of 5. 

In some sensitive lakes and streams, acidification has completely eradicated fish species, such as the brook trout, leaving these bodies of water barren. In feet, hundreds of the lakes in the Adirondacks surveyed in the NSWS have aridity levels indicative of chemical conditions unsuitable for the survival of sensitive fish species. 

The fish sensitivity to the decrease of water pH differs, however, within the salmonids. The most sensitive to acid stress are the brown trout Salmo trutta) and rainbow trout Salmo gairdneri), whereas the brook trout Salvelinus fontinalis), is generally regarded as the least sensitive. Even greater acid tolerances are seen among such teleosts as the white sucker Catostomus commersoni), the perch Perea sp.), the roach Ru-tilus rutilus), and the characinid fish of the Amazon Basin. All of these species, as a rule, can survive at pH levels to most salmonids [16]. 

Loss of most fish species, including most important sport fish species such as brook trout and Atlantic salmon few fish species able to survive and reproduce below pH 4.5 (e.g., central mud minnow, yellow perch, and in some waters, largemouth bass)... 

MacAvoy, S.E. and Bulger, A.J. (1995). Survival of brook trout (Salvelinus fonti-nalis) embryos and fry in streams of different acid sensitivity in Shenandoah National Park, USA. Water Air and Soil Pollution, 85, 439—444. 

Mirza, R. S., and Chivers, D. P., 2000, Predator-training enhances survival of brook trout evidence from laboratory and field enclosure studies, Can. J. Zool. 78 2198-2208. 

Schofield, C.L. Jr. "Water Quality in Relation to Survival of Brook Trout salvelinum fontlnalls (Mitchill)" Trans. Amer. Fisheries Soc. 94, No. 3, pp. 227-235 (1965). 

Table 2. Analysis of covariance comparing pH (X) and log A1 (Y) concentrations in stocked brook trout lakes exhibiting survival (ST+) and no survival (ST-).

Brook Trout Median survival time 18 hr. 0.080 Dandy, J.W.T 1972... 

McKim and Benoit 133) maintained brook trout under chronic exposure to copper for a period of 22 months. Copper at 32.5 /xg/liter decreased survival and growth of adult fish and substantially reduced egg fecundity and hatchability. Exposure at 17.4 jjLg Cu/liter did not adversely affect adults or hatchability of eggs, but survival of alevins and juvenile stages was reduced by 12% at 3 months and complete mortality occurred after about 6 months. The no-effect level, considered safe for all life-cycle stages, was established at 9.5 /Ltg/liter, and a value of 9.4 g/liter was determined in a subsequent study (734). All tests were performed with soft water having a hardness of 45 mg/litqr as CaCOs. 

The median survival time is the time that half the organisms in a random sample from a test population are able to survive a given level of stress. Figure 5 illustrates how median survival times are calculated. The data are taken from a study of the toxicity of low oxygen levels to juvenile brook trout (Shepard, 1955). The trout were conditioned for a period of time in water containing 10.5 mg/L dissolved oxygen and were then placed in experimental aquariums having lower concentrations of dissolved oxy-... 

The brook trout was formerly found in this Adirondaek lake in New York, but, due to acid rain, it cannot survive. 

Chivers et al. (2002) tested whether or not learned responses could result in a survival benefit, besides confirming that fish could learn unknown heterospecific cues through the diet or a predator. In a two-part study, fathead minnows were exposed to chemical stimuli collected from rainbow trout (Oncorhynchus mykiss) fed a mixed diet of either minnows and brook stickleback, or swordtail and stickleback. To test if the minnows had acquired recognition of stickleback alarm cues, Chivers et al. (2003) exposed the fish to stickleback alarm cues and introduced an unknown predator, yellow perch or northern pike. Both perch and pike took longer to initiate an attack on minnows that were previously exposed to trout fed minnows and stickleback than those previously exposed to trout fed swordtails and stickleback. These results show again that fishes are able to learn novel cues through association with known cues in a predator s diet. Furthermore, it shows that anti-predator responses to these newly learned cues could result in a survival benefit. 

A number of investigators have provided experimental evidence suggesting that brief exposures of oxidant residuals are toxic to fish. As shown in Table these studies indicate that cold water trout species are more sensitive to oxidant residuals than such warm-water forms as yellow perch, bass and fathead minnows. Bosch and Truchan (1976) found a variety of warmwater fish species (mainly centrarchids and bullheads) that were able to survive repeated 30 minute exposures of chlorine levels up to 0.5 mg/1. Yellow perch are extremely resistant to residual chlorine at low levels (Arthur et al 1 975 Brooks and Seegert, 1977), while avoidance by rainbow trout has been observed at levels of 0.001 mg/1 (Sprague and Drury, 1969). 

Scientists have documented many exampies of the effect of acid deposition on aquatic organisms. One exampie invoives the work of Dr. Ken Simmons, who investigated how acid rain affected rainbow trout in the waters of Whetstone Brook in north-centrai Massachusetts. He piaced the trout in cages in the brook so that their behavior and survivai couid be monitored. Three days iater, the trout were dead. Acid rain had iowered the pH ievei of the water to a point at which the trout simpiy couid not survive. 

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