Fish Entrainment Research Articles

On‐shore entrainment of circatidal rhythmicity inLipophrys pholis(teleostei) by natural zeitgeber and the inhibitory effect of cageing

The rocky shore fish, Lipophrys pholis, possesses an endogenous circatidal activity rhythm that eventually declines under constant conditions. Such arhythmic fish can be entrained by exposure to multiple zeitgeber for one tidal cycle on the shore. Increasing the number of tidal cycles four‐fold did not significantly increase entrainment or rhythmicity nor was entrainment enhanced by exposure to spring tides compared with neap tides. These results imply that the minimum requirement for entrainment is attained after exposure to a single neap tidal cycle. Exposure to alternate tides results in circatidal rhythmicity implying that this is the periodicity of the underlying oscillator of Lipophrys. One fish, however, alternated peaks of unequal amplitude which suggests the reinforcement of one 25h‐oscillator of an 180° antiphase pair. Cageing itself reduces rhythmicity in freshly collected fish and probably inhibits the entrainment of arhythmic fish. It is likely that confinement within the cage reduces activity, which in turn, may inhibit further activity via a positive feedback system. This may provide a mechanism for inhibiting swimming under unfavourable conditions.

Estimation of Recruitment Forgone Resulting from Larval Fish Entrainment

The effect of larvae entrainment on fish populations is difficult to determine because larvae abundance, mortality, and growth are difficult to estimate. The concept of production forgone (lost) was developed recently to avoid estimation of abundance, but estimates of mortality and growth rates for larvae, young-of-year, and juveniles are still necessary, and these too are difficult to estimate. For sportfish, production forgone is less important than recruitment, and recruitment forgone, or lost, as a result of larvae and egg entrainment could be useful for assessment of sportfish larvae and egg entrainment. A method is developed for estimation of recruitment forgone; it only requires estimates of population parameters for the mature population; it requires no estimates of abundance. The method is applied to assess yellow perch larvae entrainment at the Monroe Power Plant, Monroe, Michigan, located on the western basin of Lake Erie. The number of yellow perch larvae entrained was 1.28 x 10 8, which is an enormous number, but larvae mortality is high and the recruitment forgone was 8,933 fish.

Passage of Gizzard Shad and Threadfin Shad Larvae through a Larval Fish Net with 500-μm Openings

Accuracy of larval fish entrainment estimates at power plants depends on the effectiveness of sampling gear. Simulated tows in a laboratory flume were made to evaluate retention of gizzard shad (Dorosoma cepedianum) and threadfin shad (Dorosoma petenense) larvae in a larval fish net with 500-μm square mesh openings that is regularly used by the Tennessee Valley Authority and other investigators. Retention of 1-d-old gizzard and threadfin shad larvae (3.0-5.0 mm total length) averaged less than 15%. Average retention was 32% over all tests with tow velocity, tow duration, species, and age as variables. Retention was significantly greater at a tow speed of 1.0 m/s than at a speed of 0.5 m/s. No effect of tow duration on retention was observed. Tests conducted in static water revealed about 40% of 1- and 3-d-old threadfin shad swam through the 500-μm openings during a 5-min period and about 10% were extruded through the net when it was washed down. These results suggested that (1) the use of larval fish nets with 500-μm or larger openings does not provide representative estimates of the densities of shad larvae present in natural water bodies, (2) comparisons of larval densities based on samples collected at different towing velocities or with stationary nets versus towed nets could lead to invalid conclusions, and (3) a significant proportion of larvae are lost (extruded through the net) during net washdown.

Assessing population effects from entrainment of fish at a large volume water intake

Abstract Industrial, municipal, and agricultural activities require large volumes of water that are generally obtained from lakes, reservoirs, rivers or oceans through intake systems that may also effect aquatic and marine organisms. Quantifying these effects is often difficult and may require innovative methods. We describe a method for estimating population effects from entrainment of juvenile chinook salmon (Oncorhynchus tshawytscha) at a steam electric generating station on the Columbia River that required cooperation between power plant operators and fishery biologists. The method involved sampling fish in the river and entrained fish (both marked recaptures and naturally occurring downstream migrants) within the intake, and estimating the 1) total number of fish entrained, 2) size of the natural population, and 3) percent of the natural population affected.

Production forgone: An alternative method for assessing the consequences of fish entrainment and impingement losses at power plants and other water intakes

Losses of fish at power plant and other water intakes have immediate as well as future impacts. Not only is fish biomass removed from the aquatic system, but also the biomass that would have been elaborated by the cohort is not available to other predators. A simple biological production model was modified to allow projections of future impacts associated with current losses of fish and fish larvae. To compute these projections, it is assumed that short-term future responses with be similar to recent survival and growth rates, deducible from analysis of current population structure. The model has several advantages over the approaches. First, a dynamic population model need not be specified. Second, the relative importance of ichthyoplankton versus juvenile and adult fish losses can be compared directly. Third, the ecological effects of future losses can be addressed by cosidering the predicted size-frequency distributions. Finally, the relative uncertainty of the forecast can be assessed. The effectiveness of two commonly used mitigation techniques was explored. Reductions in entrainment-induced mortality were assessed along with exclusion of adult fish using a size selective screening device. If entrained organisms contribute most to the production forgone, then reductions in entrainment mortality will be more effective than screening of adult fish. Extensive sensitivity analysis of the model indicated the relative importance of various growth and survival parameters. Survival rates in the first year of life were critical parameters. A computer program (in FORTRAN) generates production forgone estimates by age group, evaluates the efficiency of various mitigation measures and computes the sensitivity of production forgone with respect to each parameter in the model.

Biological Monitoring of Thermal Effects of Cooling Water Discharges from Danish Power Plants

In the years from 1970-1982 52 site studies and monitoring studies have been carried out at major existing and planned power plants. The results from the studies have been used in a planning system for water quality. This planning system, which is water quality related, is described in this paper. An important part of the planning system is the description of size and distribution of excess temperature fields and the related biological conditions. In the biological monitoring, emphasis is placed on the benthic community as more vulnerable to the cooling water discharge. The studies have shown that the excess temperature field within the 1-2° isotherm can produce measurable changes in the benthic community. The temperature effect in the pelagic zone is marginal, however, some effects are seen at sites with a deep water intake of nutrient rich water. Entrainment of fish and Zooplankton can be important in bays and estuaries.

Cooling Water Flow Velocity in Relation to Collection of Entrained Larval Fish at Power Plants

Velocity of condenser cooling water at numerous sampling sites at some Great Lakes power plants was examined in relation to larval fish entrainment. Current velocity was found to differ significantly in many cases at all depths, for sampling locations spaced 1 m apart in the vertical plane. Extensive use of current meters showed that a simple, presampling study of current velocity at the intake or discharge could improve the accuracy of entrainment estimates.Key words: current velocity, larval fish, entrainment sampling, power plant

The Lake Sangchris Study

Under contract with Commonwealth Edison Company, the Illinois Natural History Survey studied this cooling lake ecosystem intensively from August 1973 through August 1977 to determine the effect of the thermal discharge and combustion byproducts on the local environment. Investigations included detailed studies of water quality, plankton, aquatic macrophytes, clams, benthos, fish, fish harvest or creel, waterfowl, trace metals, and pesticides. Some studies (water quality, benthos, clams, and aquatic macrophytes) were terminated in 1976, and others were initiated to consider the distribution of larval fishes in the cooling loop and the effect of the impingement and entrainment of fish by the power plant.
 In June 1975 , the Illinois Natural History Survey received additional support from the Electric Power Research Institute (EPRI) of Palo Alto, California, to expand investigations at Lake Sangchris. The expanded work consisted of three parts: (1) a study of the relationship between the fisheries and the physicochemical conditions associated with power production, including fish temperature preferences, potential dangers to the biological system, benefits to plant and animal communities, and causes of environmental degradation associated with power production; (2) construction of a fish production model from the large accumulation of physical-chemical-biological data; and (3) a comparison of fish production in Lake Sangchris with that of Lake Shelbyville, a nearby flood control reservoir. This work has been completed, and a four-volume final report: Evaluation of a Cooling Lake Fishery, has been published by EPRI (1979-1980). However, those investigations cannot be completely separated from the work supported by Commonwealth Edison and reported here.
 The investigative work was carried out by an interdisciplinary team of specialists. Administration and overall coordination of the project were handled at the Illinois Natural History Survey headquarters in Urbana, while field activities were coordinated through a field station at Kincaid, a few miles from the lake. Most of the fishery biologists were based at the field station; other team members were based in Urbana where more extensive laboratory and analytical facilities were available.

A Comment on the Paper by John r. M. Kelso and Gary s. Milburn: “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, 1979)

Assessment of entrainment and impingement impact of the 89 steam-electric generating stations on Great Lakes fish stocks reported by Kelso and Milburn (1979) is evaluated. Despite the large number of fish impinged at these stations, impingement losses typically constituted less than 1% of the standing stocks of fish in the lakes. Similarly, entrainment losses also represented a small fraction of total larvae in the lakes. Therefore, power plants alone probably have minimal impact on the Great Lakes sport and commercial fisheries and no detectable impact on fish populations. Despite Kelso and Milburn's assertion to the contrary, future fish losses from proposed generating capacity expansion may be less, due to improvements in cooling water intake design.

Retinal and extraretinal entrainment action spectra for the activity rhythms of the lake chub, Couesius plumbeus

The roles of retinal, pineal, and other extraretinal photoreceptors in determining light responses and the entrainment of circadian locomotor activity rhythms were investigated with a cyprinid fish, the lake chub, Couesius plumbeus. Determinations were made of the action spectra for inducing activity responses and entraining circadian activity. In normal, intact fish entrainment occurred over 368 to 742 nm with maximal sensitivity at wavelength bands centered at 538 to 568 nm (10−6−10−4 μw cm−2). In blinded and blinded-pinealectomized fish extraretinal photoreception and entrainment was restricted to approximately 568 to 742 nm. In all cases the energy fluence rates for entraining activity were significantly greater than those required for effecting activity responses.

Entrainment and Impingement of Fish by Power Plants in the Great Lakes which use the Once-Through Cooling Process

There are 89 thermal electric generating stations, producing 54,118 Megawatts (Mwe) of electricity, which use water directly from the Great Lakes. Electrical production per capita in Canada, 3.34 kw, is about twice that of the United States, 1.32 kw. These power plants require almost 2000 m 3 s −1of cooling water or, conservatively, >30% of the flow of the St. Lawrence River. Cooling water use is directly related to Mwe production and 176 L are required per kilowatt. The majority (76%) of power plants cause temperature increases of 12° C or less. Impingement of fish is directly related to power plant size (log 10 number impinged = 0.414 + 1.844 log 10 Mwe capacity) and we calculated that more than 100 × 10 6 fish will be lost at existing and proposed stations. Impingement results in direct losses to the fishery of more than 25%, by weight, of the annual commercial fish harvest. Entrainment is also directly related to power plant size (log 10 number entrained = 2.103 + 1.658 log 10 Mwe capacity) and we expect more than 1.28 × 10 9 larval fish will be lost by entrainment. These estimates of entrainment and impingement are conservative since they are based upon rated pumping capacity, not actual usage which was 67% for the few plants that provided this information. Impingement losses, when combined with entrainment losses which will affect recruitment to some unknown degree, likely constitute a significant undersirable impact upon the Great Lakes fishery.

Entrainment of Larval Fish by the Douglas Point Generating Station, Lake Huron, in Relation to Seasonal Succession and Distribution

Larval fish were sampled by net in Lake Huron and the Douglas Point generating station throughout spring, summer, and early fall 1975. Dominance shifted from fourhorn sculpin (Myoxocephalus quadricornis) to rainbow smelt (Osmerus mordax) then to ale-wife (Alosa pseudoharengus) from late April to late September. Entrainment of the major species paralleled dominance and abundance observed in the lake, but yellow perch (Perca flavescens), brook stickleback (Eucalia inconstans), and slimy sculpin (Cottus cognatus) caught in the lake — each ranging from 5 to 25% of the total catch — were not entrained. Conversely, white sucker (Catostomus commersoni) was entrained but not captured in the lake. Size of individuals entrained, upper limit approx. 40 mm, paralleled size of individuals in the lake. Vertical distribution, and thus proximity to the submerged intake, greatly influenced entrainment rate. Key words: larval fish, entrainment, power plant, distribution, abundance.

Temperature and Water Velocity Effects on the Swimming Performances of Young-of-the-Year Striped Mullet (Mugil cephalus), Spot (Leiostomus xanthurus), and Pinfish (Lagodon rhomboides)

Swimming performances of young-of-the-year striped mullet (Mugil cephalus), spot (Leiostomus xanthurus), and pinfish (Lagodon rhomboides) were tested by examining the combination of physical endurance and swimming behavior to provide information on potential fish entrainment and impingement problems at industrial intakes. Tests were conducted at three temperatures (15–25 °C) and six water velocities (12–48 cm/s). Fish lengths ranged from 1.4 to 7.0 cm TL. Fish tested at higher temperatures exhibited increased time for steady swimming and for impingement avoidance. Temperature was also positively correlated with maximum swimming speeds and with the number of bursts performed during drift–burst activity (drifting with the current and returning upstream with a burst of swimming). Increased water velocities resulted in decreased times of steady swimming and impingement avoidance, and reduced drift–burst activity. Larger fish avoided impingement longer and had faster maximum swimming speeds; however, smaller fish showed stronger rheotaxis and swam steadily for longer periods at equal water velocities. Abnormally heavy mullet and spot had reduced capabilities for position maintenance (steady swimming) which may decrease their ability to avoid impingement. Key words: swimming speeds, temperature, water current, impingement, behavior, mullet, spot, pinfish

Responses of a Fish Population Model to Young-of-the-Year Mortality

A multiple-age-class model is used to examine the effects of increases in density-independent young-of-the-year mortality caused by power plant entrainment of larval fish. It is demonstrated analytically that in all realistic cases, an increase in such mortality results in a smaller equilibrium population density of adult fish. The stability of the population with respect to perturbations about its equilibrium point is increased in these cases. However, situations can occur where a slight increase in mortality causes a catastrophic population decline. The model is used to generate autoregression graphs of population numbers that can be compared with field data. Key words: stock–recruitment, young-of-the-year mortality, compensation, Leslie matrix, mathematical model

Intake System Assessment for Central Columbia River

Four intake systems (vertical traveling screens, infiltration beds, perforated pipes located above the stream bed in the river channel, and perforated pipes located above the bed in an off-stream channel) are selected and considered for detailed evaluation of potential environmental impact. Based on all considerations of potential impacts, the best alternative is perforated pipes located above the river channel bed. This intake system is also the most economical to construct, operate, and maintain. A pivotal issue in assessing the environmental impact is the potential for impingement and entrainment of macroscopic planktonic organisms and juvenile fish without or with little swimming ability. As this impact depends largely upon approach velocities, the infiltration beds and perforated pipes located above the river channel bed are both well suited to minimize impingement and entrainment.

Design of Fish Conserving Intake System

Biological tests were conducted to determine behavioral characteristics of saltwater fish indigenous to Southern California. The results of the tests were incorporated in the design of a new intake and screenwell for coastal generating stations. Model tests show that the new offshore intake design will greatly reduce the fish entrainment problem. For those fish that are entrained, when they reach the screenwell they will be guided to a holding chamber, removed by an elevator bucket, and returned to the ocean. Earlier fish conservation methods are presented along with the biological tests and the development of the new designs. Confirming model test results are presented. These new designs will first be used at the San Onofre Nuclear Generating Station, Units 2 and 3, scheduled for operation in the early 1980s.