# NOAA Tech Memo NWFSC-7: Part 4: Environmental Effects

#### Gas Supersaturation in Lower Columbia River

In the early 1970s, extensive efforts were made to decrease levels of supersaturation created by spill including 1) increased water storage in the upper reaches of the river basin, 2) increased electrical generation at dams, and 3) installation of flow deflectors on the spillways of several dams. As a result of these actions, little evidence of GBD in salmonids was observed in the late 1970s. 

During the 1980s, however, with the implementation of increased spill at dams to improve passage of juvenile salmonids, diurnal fluctuations in supersaturation were created within the Columbia River system. The COE and the CZES Division established a field bioassay and monitoring program to evaluate the impacts of intermittent dissolved gas supersaturation on both juvenile and adult salmonids. The reservoir behind The Dalles Dam was selected as the primary evaluation site because daily spill was expected at the next upstream dam (John Day Dam). Conditions and impacts in 1985 and 1986 were described and compared with results from earlier studies. Criteria for national and state dissolved gas standards were reevaluated informally to assess whether current violations of supersaturation standards in the Columbia River Basin necessitated changes in the established criteria. Changes in water management policies and more research on biological impacts were discussed. Managers of state and federal fishery and water quality agencies were informed regarding research conclusions and the severity and frequency of supersaturation under present day conditions.

#### Bibliography

#### Mount St. Helens Eruption

Although there has yet to be a comprehensive long-term physical, chemical, and biological monitoring program in the Columbia River estuary, the eruption of Mount St. Helens fortuitously occurred during the sampling phase of the Columbia River Estuary Data Development Program (CREDDP, see ECOSYSTEM ASSESSMENTS). Although not destined to be a long-term study, CREDDP included the most comprehensive, broad-scale biological sampling of the estuary to date. Accordingly, CZES Division researchers used the available CREDDP results, as well as data from other selected studies, as a baseline against which to compare post-eruption monitoring results. These analyses produced some general observations and conclusions. After the eruption and the resulting high turbidities in the estuary, there were major changes in the abundances and feeding habits of selected fishes. For example, subyearling chinook salmon were less abundant in open-water areas of the upper estuary, more abundant in open-water areas of the central and lower estuary, and consumed fewer amphipods (Corophium spp.). Also, amphipod densities at selected locations in the estuary were significantly lower after the eruption. Since dredging often produces high turbidities, the eruption can be viewed as a natural, albeit extreme, example of how high turbidities can alter abundances and feeding habits of estuarine fishes.

#### Bibliography

Emmett, R. L., G. T. McCabe, Jr., and W. D. Muir.1991. Effects of the 1980 Mount St. Helens eruption on Columbia River estuarine fishes: implications for dredging in Northwest estuaries. In C. A. Simenstad (editor), Effects of dredging on anadromous Pacific Coast fishes, p. 74-91. Washington Sea Grant, Univ. Wash., Seattle, 160 p.

Kirn, R. A., R. D. Ledgerwood, and A. L. Jensen.1986. Diet of subyearling chinook salmon (Oncorhynchus tshawytscha) in the Columbia River estuary and changes effected by the 1980 eruption of Mount St. Helens. Northwest Sci. 60(3):191-196.

Newcomb, T. W., and T. A. Flagg.1983. Some effects of Mt. St. Helens volcanic ash on juvenile salmon smolts. Mar. Fish. Rev. 45(2):8-12.

#### Effects of Fluoride on Fish Passage

Migratory delays at John Day Dam were not decreased appreciably by changes in fishway entrance locations, water discharge volumes or configurations, or turbine operating conditions. The lack of response by migrating salmonids to flow alterations below the dam focused attention on the possibility that something in the water might be causing fish to avoid the fishways and delay their passage. 

In 1982, preliminary studies conducted by CZES Division personnel assessed the distributions of many pollutants near John Day Dam. The results of this investigation suggested that the fish-passage delays might be related to contaminants discharged at an aluminum smelter outfall located on the Washington shore 1.6 km upstream from John Day Dam. In particular, high concentrations of fluoride in the vicinity of John Day Dam (0.3-0.5 mg/L in 1982) prompted investigators to focus sampling and research efforts on this contaminant. 

In 1983 and 1984, behavior tests were conducted in which over 600 returning salmonids (chinook, coho, and chum, O. keta, salmon) were captured and tested with different concentrations of fluoride in a two-choice flume located in the spawning channel of Big Beef Creek, Washington. The conclusion from these experiments was that the behavior of upstream-migrating adult salmon would be adversely affected by fluoride concentrations of about 0.5 mg/L and that concentrations of 0.2 mg F/L were at or below the threshold for fluoride sensitivity of chinook and coho salmon. 

Beginning in 1983 and continuing through 1986, fluoride discharges from the aluminum plant were greatly reduced. This was initially due to modifications in the plant's pollution-discharge system. However, it was also during this period that the Washington Department of Ecology (WDOE) took an active interest in the results of the CZES Division's water quality and behavior tests. The WDOE lowered significantly the discharge limitations for a number of contaminants, including fluoride, in the aluminum plant's wastewater discharge permit. With the reduction in fluoride discharged from the aluminum plant, there was a corresponding drop in fluoride concentrations in the river near the outfall and John Day Dam. Concurrently, fish passage delays and interdam losses of adult salmon decreased to acceptable levels.

#### Bibliography

Damkaer, D. M., and D. B. Dey.1984. Adult fish delay at John Day Dam. Report to U.S. Army Corps of Engineers, Contract DACW57-83-F-0323, 26 p. + Appendix. (Available from Northwest Fisheries Science Center, 2725 Montlake Blvd. E., Seattle, WA 98112-2097.)

Damkaer, D. M., and D. B. Dey.1985. Effects of water-borne pollutants on salmon-passage at John Day Dam, Columbia River (1982-1984). Final Report to U.S. Army Corps of Engineers, Contract DACW57-84-F-0173, 85 p. (Available from Northwest Fisheries Science Center, 2725 Montlake Blvd. E., Seattle, WA 98112-2097.)

Damkaer, D. M., and D. B. Dey.1986. Effects of water-borne pollutants on salmon-passage at John Day Dam, Columbia River (1982-1986). Final Report to U.S. Army Corps of Engineers, Contract DACW57-85-H-0001, 42 p. + Appendix. (Available from Northwest Fisheries Science Center, 2725 Montlake Blvd. E., Seattle, WA 98112-2097.)

Damkaer, D. M., and D. B. Dey.1989. Evidence for fluoride effects on salmon passage at John Day Dam, Columbia River, 1982-1986. N. Am. J. Fish. Manage. 9:154-162.

#### Effects of Enhanced Ultraviolet Radiation on Zooplankton

From 1976 to 1984, the Division conducted research on the effects of enhanced solar radiation on near-surface marine zooplankton. Zooplankton include nearly all groups of aquatic animals, at least for some phase in their life-history, such as the egg or larval stage. Zooplankton are found at all depths, depending on species and season, but are most abundant in the sunlit upper 100 m, where the bulk of their food, including the phytoplankton, is found. Zooplankton are critical components in aquatic food webs, concentrating in larger animals, including fish and shellfish which are the basis of important fisheries. 

Different species of shrimp and crab larvae, euphausiids, and copepods were collected from the near-surface layer and exposed to various levels of simulated solar UV radiation. Comparisons between solar and artificial spectra were based on spectroradiometric measurements. Generally, the zooplankton species tested tolerated UV-B irradiance up to threshold levels with no significant reduction in survival or developmental rates. Beyond the established threshold levels, activity, development, and survival rapidly declined. The apparent UV radiation thresholds are near present incident UV radiation levels, and our findings were consistent with the conclusion that solar UV radiation, even at present levels, may control the seasonal vertical distribution of many of these animals. In addition to determining the dose and dose-rate responses of these zooplankton species, the questions of photorepair and behavioral response were also investigated. The results of these studies demonstrated the occurrence and light requirements of photorepair mechanisms in several important zooplankton species. They also revealed the apparent inability of many of these species to detect and avoid harmful levels of UV-B irradiance.

#### Bibliography

Damkaer, D. M., D. B. Dey, and G. A. Heron.1981. Dose/dose-rate responses of shrimp larvae to UV-B radiation. Oecologia (Berl.) 48:178-182.

Damkaer, D. M.1982. Possible influences of solar UV radiation in the evolution of marine zooplankton. In J. Calkins (editor), The role of solar ultraviolet radiation in marine ecosystems, NATO Conf. Series IV: Marine Sciences, Vol. 7, p.701-706. Plenum Press, New York.

Damkaer, D. M., and D. B. Dey.1982. Nomograms for biologically effective UV. In J. Calkins (editor), The role of solar ultraviolet radiation in marine ecosystems, NATO Conf. Series IV: Marine Sciences, Vol. 7, p.205-211. Plenum Press, New York.

Damkaer, D. M., and D. B. Dey.1982. Short-term responses of some planktonic Crustacea exposed to enhanced UV-B radiation. In J. Calkins (editor), The role of solar ultraviolet radiation in marine ecosystems, NATO Conf. Series IV: Marine Sciences, Vol. 7, p.417-427. Plenum Press, New York.

Damkaer, D. M., and D. B. Dey.1983. UV damage and photoreactivation potentials of larval shrimp, Pandalus platyceros, and adult euphausiids, Thysanoessa raschii. Oecologia (Berl.) 60:169-175.

Dey, D. B., D. M. Damkaer, and G. A. Heron.1988. UV-B dose/dose-rate responses of seasonally abundant copepods of Puget Sound. Oecologia (Berl.) 76(3):321-329.

#### Effects of Spectral Irradiance on Early Development of Salmon

From 1980 to 1983, experiments were conducted by CZES Division personnel during fall, winter, and early spring at the Northwest Fisheries Science Center in Seattle, Washington. Eggs and milt were obtained from fully mature fall chinook salmon returning to Portage Bay (Lake Union), the site of the center. In the experiments, freshly fertilized eggs, alevins, and fry were exposed to artificial light sources of different spectral distributions and irradiances. Measurements of spectral irradiance were made with a spectroradiometer which measures instantaneous irradiance at each wavelength (W/m2), and this was converted to daily irradiance (kJ/m2). 

Survival, eyeing, hatching, and length and weight data from the 3-year study suggested that 1) all light is not harmful to chinook salmon eggs, alevins, and fry; 2) ultraviolet light (285-390 nm) of spectral irradiance above 10-3 W/m2 (8 h/d) is harmful to chinook salmon eggs, alevins, and fry; 3) visible light (390-800 nm) of spectral irradiance above 10-2 W/m2 (8 h/d) is harmful to chinook salmon eggs; 4) chinook salmon eggs are more vulnerable to both ultraviolet light and visible light than are alevins and fry; and 5) semidarkness or the irradiance of pink fluorescent lamps may benefit chinook salmon fry in terms of weight gain. Results indicated that chinook salmon eggs may be exposed to 50-100 kJ/m2 of artificial light daily from incandescent bulbs, filtered pink fluorescent lamps, or conventional fluorescent room lighting without being adversely affected in their viability or hatching rate or the size of the fry. An approximate threshold for safe combinations of daily ultraviolet (UV) and visible irradiance (VIS) for chinook salmon eggs, alevins, and fry may be determined from the expression 150 = 150(UV) + VIS.

#### Bibliography

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