- Email: [email protected]
Response to Comment by J. Scott-Wasilk et al
COMMENT AND RESPONSE TO COMMENT Lake Michigan, 1967-1978. Administrative Report, Great Lakes Fish. Lab., Ann Arbor, Mich. Kelso, J. R. M., and Milburn, G. S. 1979. Entrainment and impingement of fish by power plants in the Great Lakes which use the once-through cooling process. J. Great Lakes Res. 5:182-194. King, R. G. 1978. Entrainment of Missouri River fish larvae through Fort Calhoun Station, pp. 45-56. In Fourth National Workshop on Entrainment and Impingement. L. D. Jensen, ed. EA Communications, Melville, New York. McFadden, J. T. 1977. An argument supporting the reality of compensation in fish populations and a plea to let them exercise it, pp. 153-183. In Proceedings of the Conference on Assessing the Effects of PowerPlant-Induced Mortality on Fish Populations. W. Van Winkle ed. Pergamon Press, New York. Murarka, I. P. 1977. A model for predicting fish impingement at cooling water intakes." Argonne National Laboratory Report AA-8. Power Authority of the State of New York. 1977. James A. Fitzpatrick Nuclear Power Plant 316(b) Demonstration. Scott, W. B., and Crossman, E. J. 1973. Freshwater Fishes of Canada. Fish. Res. Board Can. Bull. 184. Smith, S. H. 1970. Species interactions of the alewife in the Great Lakes. Trans. Amer. Fish. Soc. 99:754-765. Spigarelli, S. A., Jensen, A. L., and Thommes, M. M. 1981. An assessment of the impacts of water intakes on alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), and yellow perch (Perea j7.avescens) populations in Lake Michigan. EPA-905/ 3-81001. Stevens, D. E., and Finlayson, B. J. 1978. Mortality of young striped bass entrained at two power plants in the Sacramento-San Joaquin Delta, California, pp. 57-69. In Fourth National Workshop on Entrainment and Impingement. L. D. Jensen, ed. EA Communications, Melville, New York.
495
Thomas, D. L., and Miller, G. J. 1977. Impingement studies at the Oyster Creek Generating Station, Forked River, New Jersey from September to December 1975, pp. 317-341. In Third National Workshop on Entrainment and Impingement. L. D. Jensen, ed. Ecological Analysts, Inc., Melville, New York. Van Oosten, J. 1947. Mortality of Smelt, Osmerus mordax, in Lakes Huron and Michigan during the fall and winter of 1942-1943. Trans. Amer. Fish. Soc. 74:310-337. Wells, L., and R. W. Hatch. 1981. Status of bloater chubs, alewives, smelt and slimy sculpins in Lake Michigan (with observations on the performance of Green Lake strain lake trout planted on the Sheboygan Reef). A report presented at the March 1981 Great Lakes Fishery Commission Lake Michigan Committee Meeting. Jennifer Scott-Wasilk l Toledo Edison Company Toledo, Ohio 43652 Rudy Kunshek Commonwealth Edison Company Chicago, Illinois 60690 David T. Michaud Wisconsin Electric Power Company Milwaukee, Wisconsin 53201 Alan E. Gaulke American Electric Power Service Corporation Canton, Ohio 44701 John H. Balletto Public Service Electric and Gas Company _ _ _ _ _ _ _N_e_w_a_rk~,~New Jersey 07101 IAddress correspondence to J. Scott-WasHko
RESPONSE TO COMMENT BY J. SCOTT-WASILK et al.
We are pleased that our examination of Great Lakes power plants with their associated entrainment and impingement of fishes (Kelso and Milburn 1979) has captured the attention of at least a few (Scott-Wasilk et al. 1981). It is disappointing, however, to note both the fragmented examination of what we attempted to do and the incomplete grasp of the management initiatives proposed for aquatic resources, particularly the Great Lakes (Johnson 1980, Science Advisory Board 1978).
Indisputably, there are 89 thermal electric generating stations using water directly from the five Great Lakes (Kelso and Milburn 1979). These power plants when viewed singly often appear to have minimal local impact, yet it has been recognized that the potential for population or lakewide effect exists (Schubel and March 1978, Milburn and Ginsberg 1977). Consequently, we chose (Kelso and Milburn 1979) to examine all data from all Great Lakes to provide an analysis which was
496
KELSO and MILBURN
"obviously only a first step" in examining the impact of entrainment and impingement in the Great Lakes. Scott-Wasilk et al. (1981) presented data from Lake Michigan where the data base is considerable, the western basins of Lake Erie and Lake Ontario. With the exception of Lake Michigan, the data base for standing stock estimates for other lakes is at best incomplete. The only fishery yardstick available to us was the estimates of com" mercial landings made in each of the Great Lakes. As our primary purpose was to examine water use by the thermal electric generating industry and to analyze its cumulative entrainment and impingement, these data are now available for all the Great Lakes for comparison to standing stock, commerciallandings, or other comparators as they become available. If Scott-Wasilk et al. had compared entrainment and impingement with fish stocks in all Great Lakes, their contentions might then become more meaningful. Further, as we clearly stated, entrainment will almost certainly reduce recruitment, but it is unknown to what degree. Survival in the early life stage of fishes is poorly understood, although it is known that extremely high mortality must be experienced in each new year class (May 1974). Further, most mortality appears to occur in the egg stage (Bannister, Harding, and Lockwood 1974) with progressively greater survival during the pelagial period. Consequently, simplistic unsupported assumptions of fecundity .and survival (Scott-Wasilk et al. 1981) are often more misleading in interpreting entrainment impacts upon a "patchily" distributed motile stage than simply a recognition of the magnitude of entrained larvae. We expect that greatest mortality has already occurred once young-of-the-year are prone to both net capture and entrainment, leading us to the conclusion that these entrainment losses are of concern in the management of an ecosystem. Scott-Wasilk et al. indicate that our analysis of entrainment ignored factors which can affect entrainment, e.g. intake design, intake location, etc. This is correct, but occurred because only the relationship between power plant size and impingement (p. 188) and entrainment (p. 190) was significant statistically and strongly correlated in the data (which was the total population and not a data subset). Thus, whatever local, short-term influence factors have upon entrainment and impingement in general, the picture remains as described with power plant size being the dominant controlling variable.
Several points made by Scott-Wasilk et al. are worth extracting. First, we agree that future losses may be less than expected in part because of decreased expansion by the utilities (Kelso and Milburn 1979, p. 193) and in part because of improving technology. However, many large nuclear and fossil fuel facilities were built during the 1970s and their water use and associated entrainment and impingement losses are large. These facilities will probably be operating for at least 30 more years and industry efforts to reduce fishlosses at these facilities have often been slow or nonexistent. The smaller, older facilities are often not the worst in terms of numbers of fish lost or regulatory concern. Second, although losses of alewife and smelt incurred by use of once-through cooling may be small in Lake Michigan, these losses may be a significant reduction in the forage base for trout and salmon. Other Great Lakes, e.g. Lake Erie, may also be suffering direct effects (Patterson 1980). In their discussion of Table 3 Scott-Wasilk et al. note, "The seemingly greater impact for the single power plant on Lake Erie ... is the result of comparing fish losses with fish stocks in the immediate vicinity of the power plant in the western basin. If estimates of fish stocks on a lakewide basis had been used, relative impacts would have been substantially less."
It should be noted that there are three additional
U.S. power plants on the western basin, one of which is estimated to entrain more larvae than the facility shown (which we assume is the Monroe power plant). There are, in addition, several other facilities which withdraw water and fish from the western basin, including one Canadian power plant and several facilities on tributaries. The combined impact of these power plants and other smaller municipal and industrial intakes has been the subject of research and concern by U.S. state and federal agencies. When these combined impacts were examined, the conclusion was that the losses may be significant for some species (patterson 1980). Further, comparing losses in a lake basin to lakewide populations, as suggested by Scott-Wasilk et al., 1981) ignored such factors as discreet stocks and local populations which may be depleted by clustering once-through facilities in areas such as the western basin of Lake Erie and the southern basin of Lake Michigan. While we believe that losses generally should be compared to populations and that stresses beyond entrainment and impingement must be considered, we do not believe that
RESPONSE TO COMMENT
losses to local areas of local populations can be ignored. Thirdly, even if entrainment mortality is assumed to be less than 100%, our severe underestimate of entrainment (p. 190 and Patterson 1977 and 1980) still indicates the potential severity of the problem. Larval survival estimates after entrainment tell us little about ultimate larval survival. Estimates of larval survival based upon real or simulated condenser passage, even allowing for delayed mortality, at best raise more questions than they answer. Finally, some man-induced mortality factors such as commercial and sport fishing are regulated and can be reduced fairly readily (i.e. in a matter of months or by the next season). Entrainment losses from existing facilities are not readily reduced. Thus, the ability to reduce losses when necessary is generally not available. When populations are depressed, power plant losses continue to further reduce recruitment, and the impact of entrainment will be most significant when populations are already stressed. Surely, the use of once-through cooling, when it uses such large water volumes and extracts fish which are not utilized in any way and which are in exceess of 25% of the total annual commercial fish harvest, deserves serious consideration when managing factors affecting the Great Lakes fishery.
497
Lakes which use the once-through cooling process. J. Great Lakes Res. 5:182-194. May, R. C. 1974. Larval mortality in marine fishes and the critical period concept. In J. H. S. Blaxter ed., The Early Life History of Fish. Springer-Verlag, N.Y., Heidelberg, Berlin. Milburn, G. S., and Ginsberg, G. C. 1977. Regulatory developments in Section 316(b), pp. 11-20. In Fourth National Workshop on Entrainment and Impingement. L. D. Jensen ed. E.A. Communications, Melville, N.Y. Patterson, R. L. 1979. Ichthyoplankton losses in western Lake Erie in 1975-77. Progress report for current budget year. USEPA grant number R 806565. (unpublished report). ____ , 1980. An investigation of levels of entrainment of four species of ichthyoplankton by four power plants in western Lake Erie in 1975-77 and the impact on juvenile recruitment. Final report USEPA grant number R806565. (unpublished report). Schubel, J. R., and Marcy, B. C., eds. 1978. Power Plant Entrainment. A Biological Assessment. Academic Press, N.Y. Science Advisory Board. 1978. The ecosystem approach. Scope and implications of an ecosystem approach to transboundary problems in the Great Lakes basin. International Joint Commission, Windsor, Ontario. Scott-Wasilk, J., Kunshek, R., Michand, D. T., Gaulke, A. E., and Balletto, J. H. 1981. A comment on "Entrainment and impingement of fish by power plants in the Great Lakes which use the once-through cooling process." J. Great Lakes Res. 7(4):491-495.
REFERENCES Bannister, R. C. A., Harding, D., and Lockwood, S. J. Larval mortality and subsequent year-class strength in the plaice (Pleuronectes platessa L.). In J. H. S. Blaxter ed., The Early Life History of Fish. SpringerVerlag, N.Y., Heidelberg, Berlin. Johnson, M. G. 1980. Great Lakes environmental protection policies from a fisheries perspective. Can. J. Fish. A quat. Sci. 37:1196-1204. Kelso, J. R. M., and Milburn, G. S. 1979. Entrainment and impingement of fish by power plants in the Great
John R. M. Kelso Canada Dept. Fisheries and Oceans Great Lakes Biolimnology Laboratory 875 Queen Street East Sault Ste. Marie, Ontario P6A 2B3 Gary S. Milburn U.S. Environmental Protection Agency Region V, 230 East Dearborn St. Chicago, Illinois 60604
495
Thomas, D. L., and Miller, G. J. 1977. Impingement studies at the Oyster Creek Generating Station, Forked River, New Jersey from September to December 1975, pp. 317-341. In Third National Workshop on Entrainment and Impingement. L. D. Jensen, ed. Ecological Analysts, Inc., Melville, New York. Van Oosten, J. 1947. Mortality of Smelt, Osmerus mordax, in Lakes Huron and Michigan during the fall and winter of 1942-1943. Trans. Amer. Fish. Soc. 74:310-337. Wells, L., and R. W. Hatch. 1981. Status of bloater chubs, alewives, smelt and slimy sculpins in Lake Michigan (with observations on the performance of Green Lake strain lake trout planted on the Sheboygan Reef). A report presented at the March 1981 Great Lakes Fishery Commission Lake Michigan Committee Meeting. Jennifer Scott-Wasilk l Toledo Edison Company Toledo, Ohio 43652 Rudy Kunshek Commonwealth Edison Company Chicago, Illinois 60690 David T. Michaud Wisconsin Electric Power Company Milwaukee, Wisconsin 53201 Alan E. Gaulke American Electric Power Service Corporation Canton, Ohio 44701 John H. Balletto Public Service Electric and Gas Company _ _ _ _ _ _ _N_e_w_a_rk~,~New Jersey 07101 IAddress correspondence to J. Scott-WasHko
RESPONSE TO COMMENT BY J. SCOTT-WASILK et al.
We are pleased that our examination of Great Lakes power plants with their associated entrainment and impingement of fishes (Kelso and Milburn 1979) has captured the attention of at least a few (Scott-Wasilk et al. 1981). It is disappointing, however, to note both the fragmented examination of what we attempted to do and the incomplete grasp of the management initiatives proposed for aquatic resources, particularly the Great Lakes (Johnson 1980, Science Advisory Board 1978).
Indisputably, there are 89 thermal electric generating stations using water directly from the five Great Lakes (Kelso and Milburn 1979). These power plants when viewed singly often appear to have minimal local impact, yet it has been recognized that the potential for population or lakewide effect exists (Schubel and March 1978, Milburn and Ginsberg 1977). Consequently, we chose (Kelso and Milburn 1979) to examine all data from all Great Lakes to provide an analysis which was
496
KELSO and MILBURN
"obviously only a first step" in examining the impact of entrainment and impingement in the Great Lakes. Scott-Wasilk et al. (1981) presented data from Lake Michigan where the data base is considerable, the western basins of Lake Erie and Lake Ontario. With the exception of Lake Michigan, the data base for standing stock estimates for other lakes is at best incomplete. The only fishery yardstick available to us was the estimates of com" mercial landings made in each of the Great Lakes. As our primary purpose was to examine water use by the thermal electric generating industry and to analyze its cumulative entrainment and impingement, these data are now available for all the Great Lakes for comparison to standing stock, commerciallandings, or other comparators as they become available. If Scott-Wasilk et al. had compared entrainment and impingement with fish stocks in all Great Lakes, their contentions might then become more meaningful. Further, as we clearly stated, entrainment will almost certainly reduce recruitment, but it is unknown to what degree. Survival in the early life stage of fishes is poorly understood, although it is known that extremely high mortality must be experienced in each new year class (May 1974). Further, most mortality appears to occur in the egg stage (Bannister, Harding, and Lockwood 1974) with progressively greater survival during the pelagial period. Consequently, simplistic unsupported assumptions of fecundity .and survival (Scott-Wasilk et al. 1981) are often more misleading in interpreting entrainment impacts upon a "patchily" distributed motile stage than simply a recognition of the magnitude of entrained larvae. We expect that greatest mortality has already occurred once young-of-the-year are prone to both net capture and entrainment, leading us to the conclusion that these entrainment losses are of concern in the management of an ecosystem. Scott-Wasilk et al. indicate that our analysis of entrainment ignored factors which can affect entrainment, e.g. intake design, intake location, etc. This is correct, but occurred because only the relationship between power plant size and impingement (p. 188) and entrainment (p. 190) was significant statistically and strongly correlated in the data (which was the total population and not a data subset). Thus, whatever local, short-term influence factors have upon entrainment and impingement in general, the picture remains as described with power plant size being the dominant controlling variable.
Several points made by Scott-Wasilk et al. are worth extracting. First, we agree that future losses may be less than expected in part because of decreased expansion by the utilities (Kelso and Milburn 1979, p. 193) and in part because of improving technology. However, many large nuclear and fossil fuel facilities were built during the 1970s and their water use and associated entrainment and impingement losses are large. These facilities will probably be operating for at least 30 more years and industry efforts to reduce fishlosses at these facilities have often been slow or nonexistent. The smaller, older facilities are often not the worst in terms of numbers of fish lost or regulatory concern. Second, although losses of alewife and smelt incurred by use of once-through cooling may be small in Lake Michigan, these losses may be a significant reduction in the forage base for trout and salmon. Other Great Lakes, e.g. Lake Erie, may also be suffering direct effects (Patterson 1980). In their discussion of Table 3 Scott-Wasilk et al. note, "The seemingly greater impact for the single power plant on Lake Erie ... is the result of comparing fish losses with fish stocks in the immediate vicinity of the power plant in the western basin. If estimates of fish stocks on a lakewide basis had been used, relative impacts would have been substantially less."
It should be noted that there are three additional
U.S. power plants on the western basin, one of which is estimated to entrain more larvae than the facility shown (which we assume is the Monroe power plant). There are, in addition, several other facilities which withdraw water and fish from the western basin, including one Canadian power plant and several facilities on tributaries. The combined impact of these power plants and other smaller municipal and industrial intakes has been the subject of research and concern by U.S. state and federal agencies. When these combined impacts were examined, the conclusion was that the losses may be significant for some species (patterson 1980). Further, comparing losses in a lake basin to lakewide populations, as suggested by Scott-Wasilk et al., 1981) ignored such factors as discreet stocks and local populations which may be depleted by clustering once-through facilities in areas such as the western basin of Lake Erie and the southern basin of Lake Michigan. While we believe that losses generally should be compared to populations and that stresses beyond entrainment and impingement must be considered, we do not believe that
RESPONSE TO COMMENT
losses to local areas of local populations can be ignored. Thirdly, even if entrainment mortality is assumed to be less than 100%, our severe underestimate of entrainment (p. 190 and Patterson 1977 and 1980) still indicates the potential severity of the problem. Larval survival estimates after entrainment tell us little about ultimate larval survival. Estimates of larval survival based upon real or simulated condenser passage, even allowing for delayed mortality, at best raise more questions than they answer. Finally, some man-induced mortality factors such as commercial and sport fishing are regulated and can be reduced fairly readily (i.e. in a matter of months or by the next season). Entrainment losses from existing facilities are not readily reduced. Thus, the ability to reduce losses when necessary is generally not available. When populations are depressed, power plant losses continue to further reduce recruitment, and the impact of entrainment will be most significant when populations are already stressed. Surely, the use of once-through cooling, when it uses such large water volumes and extracts fish which are not utilized in any way and which are in exceess of 25% of the total annual commercial fish harvest, deserves serious consideration when managing factors affecting the Great Lakes fishery.
497
Lakes which use the once-through cooling process. J. Great Lakes Res. 5:182-194. May, R. C. 1974. Larval mortality in marine fishes and the critical period concept. In J. H. S. Blaxter ed., The Early Life History of Fish. Springer-Verlag, N.Y., Heidelberg, Berlin. Milburn, G. S., and Ginsberg, G. C. 1977. Regulatory developments in Section 316(b), pp. 11-20. In Fourth National Workshop on Entrainment and Impingement. L. D. Jensen ed. E.A. Communications, Melville, N.Y. Patterson, R. L. 1979. Ichthyoplankton losses in western Lake Erie in 1975-77. Progress report for current budget year. USEPA grant number R 806565. (unpublished report). ____ , 1980. An investigation of levels of entrainment of four species of ichthyoplankton by four power plants in western Lake Erie in 1975-77 and the impact on juvenile recruitment. Final report USEPA grant number R806565. (unpublished report). Schubel, J. R., and Marcy, B. C., eds. 1978. Power Plant Entrainment. A Biological Assessment. Academic Press, N.Y. Science Advisory Board. 1978. The ecosystem approach. Scope and implications of an ecosystem approach to transboundary problems in the Great Lakes basin. International Joint Commission, Windsor, Ontario. Scott-Wasilk, J., Kunshek, R., Michand, D. T., Gaulke, A. E., and Balletto, J. H. 1981. A comment on "Entrainment and impingement of fish by power plants in the Great Lakes which use the once-through cooling process." J. Great Lakes Res. 7(4):491-495.
REFERENCES Bannister, R. C. A., Harding, D., and Lockwood, S. J. Larval mortality and subsequent year-class strength in the plaice (Pleuronectes platessa L.). In J. H. S. Blaxter ed., The Early Life History of Fish. SpringerVerlag, N.Y., Heidelberg, Berlin. Johnson, M. G. 1980. Great Lakes environmental protection policies from a fisheries perspective. Can. J. Fish. A quat. Sci. 37:1196-1204. Kelso, J. R. M., and Milburn, G. S. 1979. Entrainment and impingement of fish by power plants in the Great
John R. M. Kelso Canada Dept. Fisheries and Oceans Great Lakes Biolimnology Laboratory 875 Queen Street East Sault Ste. Marie, Ontario P6A 2B3 Gary S. Milburn U.S. Environmental Protection Agency Region V, 230 East Dearborn St. Chicago, Illinois 60604