Dennis J. Dunning

Alewives Avoid High-Frequency Sound

Abstract We studied the response of the alewife Alosa pseudoharengus to high-frequency sound to develop an acoustic system for preventing fish from entering power plant intakes. Four groups of alewives were subjected to different frequencies of sounds ranging from 110 to 150 kHz at sound pressure levels (SPLs, given in decibels [dB] in reference to 1 μPa) ranging from 125 to 180 dB. Each group of 20 or 25 fish was tested in a cage that was suspended in a flooded rock quarry. During the day, alewives schooled and strongly avoided pulsed tones (500 ms pulses, 1,000 ms apart) of 110 and 125 kHz at or above 175 dB, a continuous tone of 125 kHz at 172 dB, and pulsed broadband sound between 117 and 133 kHz at or above 157 dB. Although alewives habituated to tones, they avoided pulsed broadband sound at 163 dB more consistently. In one test, alewives did not habituate to this sound after 150 min of repeated exposure, The more consistent response to the broadband sound was probably due to the range of frequencies...

Response of Alewives to High-Frequency Sound at a Power Plant Intake on Lake Ontario

Abstract From April through June 1991, we tested a full-scale deterrent system for excluding alewives Alosa pseudoharengus from the intake of the James A. FitzPatrick Nuclear Power Plant (JAF), near Oswego, New York. This electronic system produced high-frequency broadband sound (122–128 kHz) at a source level (in decibels [dB] in reference to 1 μPa) of 190 dB. When the system was on, the density of fish near the JAF intake decreased by as much as 96% and the number of alewives impinged on the intake screens at JAF decreased by as much as 87%. The system was effective during both day and night, and its range was greater than 80 m.

Range dynamics of Hudson River striped bass along the Atlantic coast

Abstract We analyzed the movements of Hudson River striped bass Morone saxatilis along the Atlantic coast from the results of a tagging program conducted in the Hudson River estuary between 1984 and 1988. Almost 30,000 striped bass were marked with internal anchor tags; most measured between 200 and 800 mm total length (TL). Interpretations of recoveries are conditional because the distribution and selectivity of fishing effort along the Atlantic coast are unknown. The proportion of total recaptures from outside the Hudson River increased significantly with fish length and by season from spring through autumn. The geographic range of recoveries extended from the Bay of Fundy, Nova Scotia, to Cape Hatteras, North Carolina – a coastal range of about 1,500 km. Most fish recaptured in spring had traveled north and east; recoveries from south of the New York Bight were uncommon until autumn. Many recaptures came from tributaries; far northern recaptures, in particular, tended to occur in rivers or near river m...

Multiattribute utility analysis for addressing Section 316(b) of the Clean Water Act

Abstract We believe that the fundamental issues associated with implementing Section 316(b) of the Clean Water Act are whether or not it requires a balancing of objectives and if it does, how that balancing should be done. If balancing is required, we recommend the use of multiattribute utility analysis (MUA). MUA is a formal, analytic approach for evaluating and comparing options for decisions with multiple objectives. It differentiates the two types of judgments needed for public policy decisions: (1) value judgments, which indicate what people want to happen as the result of a decision and their willingness to make tradeoffs, and (2) scientific judgments, which indicate what scientists or other technical specialists think is likely to happen based on the option that is chosen. MUA provides an approach for deciding what is an ‘adverse environmental impact’ and what is ‘best technology available’ based on site-specific considerations that can be consistently applied to all cooling water intakes. To illustrate the first step of a collaborative MUA process, we present a preliminary hierarchy of objectives constructed during a 1-day meeting held with regulators, electric utilities, and environmental groups to address the renewal of SPDES permits for four power plants operating on the Hudson River.

Tag Retention by, and Tagging Mortality of, Hudson River Striped Bass

Abstract The retention of two external tags by striped bass Morone saxatilis was determined directly by holding fish in the Hudson River, New York, in 1984 for up to 24 h (absolute retention) and indirectly by examining fish released into the Hudson River and recaptured up to 2 years later (relative retention). The tags were: (1) an anchor tag, placed into the dorsal musculature, and (2) an internal anchor tag, inserted through an incision in the abdominal musculature. The absolute retention of these tag types, and of a dart tag inserted into the dorsal musculature, also was determined by holding striped bass in outdoor pools for up to 180 d. Retention of anchor tags and internal anchor tags was 100% for striped bass held 24 h in the Hudson River. Retention of internal anchor tags (98.0%) was significantly higher than that of anchor tags (42.0%) among fish at large in the Hudson River for 1 year; in the second year, only internal anchor tags were recovered. Striped bass in holding pools retained anchor ta...

Use of a Particle-tracking Model for Predicting Entrainment at Power Plants on the Hudson River

A major assumption of the Empirical Transport Model (ETM), widely adopted by both electric utilities and regulatory agencies for estimating the effects of entrainment mortality on fish populations in estuaries, is that the fraction of ichthyoplankton entrained varies only in response to changes in water withdrawals, not to changes in freshwater flow. We evaluated this assumption using a particle-tracking model to estimmate the probability of entrainment at power plants on the Hudson River during low and high freshwater flow periods and comparing those probabilities with estimates calculated from the ETM. We found that freshwater flow had a profound effect on the probability of entrainment. Both the number of river regions from which particles were entrained and the probabilities of entrainment for particles in those river regions differed between low-flow and high-flow periods. During high flow, particles spent less time in the grid box next to the intakes, reducing the probability of entrainment for particles released in the river region of each power plant and the average probability of entrainment across all regions at three power plants. The reduced probability of entrainment for particles released in the river regions of two power plants was offset by higher entrainment for particles upriver of these power plants. Although the average probabilities of entrainment across all river regions estimated with the particle-tracking model and the ETM were relatively similar for some power plants at high flow, low flow, or both, the probabilities for each river region differed considerably between the models. The number of river regions from which particles were entrained using the ETM was consistently undersestimated, resulting in probabilities for regions where entrainment occurred that were biased high compared with the particle-tracking model.

Use of Atlantic Tomcod and other Prey by Striped Bass in the Lower Hudson River Estuary during Winter

Abstract Striped bass Morone saxatilis and Atlantic tomcod Microgadus tomcod are common in the lower Hudson River estuary during winter. However, there is no information on the consumption of Atlantic tomcod or other prey by striped bass at that time in the lower Hudson River estuary. Striped bass are known to feed on Atlantic tomcod in the Hudson River during seasons other than winter. From 1986 through 1994, the stomach contents of 1,580 striped bass caught in the lower Hudson River estuary at water temperatures below 10°C were examined to determine the presence of fish and invertebrates. Of those, 47% contained food. No Atlantic tomcod were found in any of the striped bass stomachs despite the fact that 74% of the catches from the 5,826 tows we examined contained both Atlantic tomcod and striped bass and that the Atlantic tomcod appeared to be a suitable-size prey for the striped bass. The proportion of stomachs having invertebrates declined with increasing length of striped bass and the proportion of ...

Notes: A Morphological Explanation for Size-Dependent Anchor Tag Loss from Striped Bass

Abstract The potential consequences of the relationship between the design of the anchor (Dennison) tag and the morphology of its attachment site has never been considered. During 1976 and 1977, anchor tags (Floy FD-67C) were inserted in Hudson River striped bass Morone saxatilis in a location that should have resulted in the anchor of the tag lodging between the distal tips of the 18th and 19th neural spines. Although the distance between neural spines increases with fish length, tag anchors of the same length (10 mm) were used on all fish in 1976 and 1977. We later measured the gap between the 18th and 19th neural spines on 13 striped bass that were 102–655 mm total length and found, through linear regression, that a gap of 10 mm or more should occur in fish 592 mm or longer. Based on recaptures by anglers during 1976 and 1977, the number of days at large and the proportion of fish recaptured 50–365 d after tagging was significantly lower for fish that were 592 mm or longer than for fish shorter than 59...

Management Briefs: Long-Term Retention of Anchor Tags and Internal Anchor Tags by Striped Bass

Abstract During 1984, 749 striped bass Morone saxatilis were captured, marked with both anchor (Dennison) and internal anchor tags, and released in the Hudson River. The difference in the relative retention rate between the anchor tag (42%) and the internal anchor tag (98%) was large during the first recapture year and became more pronounced during the second through sixth recapture years (2% and 98%, respectively). The longest that a fish with an anchor tag was at large was 908 d. In contrast, 21 fish with an internal anchor tag were at large for longer periods, as much as 2,127 d. These results show that when multiyear recaptures are desired for long-lived species, the internal anchor tag offers the potential for statistically higher recapture rates than does the anchor tag.

Assessing Potential Effects of Entrainment and Impingement on Fish Stocks of the New York–New Jersey Harbor Estuary and Long Island Sound

Abstract We assessed the potential effects of entrainment and impingement at the Charles Poletti Power Project (hereafter, Poletti) on fish stocks of the New York–New Jersey (NY–NJ) Harbor Estuary and Long Island Sound by (1) estimating, for five fish stocks, the conditional mortality rate (CMR) for entrainment of eggs, larvae, and young-of-the-year (age-0) fish and the CMR for impingement of age-0 fish, and (2) for two of those stocks, using the CMR estimates to calculate the proportional reduction in biomass of spawners from an unfished stock under equilibrium conditions. Estimates of entrainment CMR for eggs and larvae were low and ranged from 0.02% for tautogs Tautoga onitis to 0.11% for Atlantic menhaden Brevoortia tyrannus, based on the spatial and temporal distribution of those life stages in the NY–NJ Harbor Estuary and Long Island Sound study area and the probabilities of entrainment generated by a particle tracking model, coupled with a three-dimensional estuarine circulation model that simulate...