Nongame Fish Research Articles

Competition between Kokanees and Utah Chub in Flaming Gorge Reservoir, Utah–Wyoming

Kokanees Oncorhynchus nerka (lacustrine sockeye salmon) and Utah chub Gila atraria feed extensively on similar sizes and species of zooplankton in Flaming Gorge Reservoir. We measured the effects of Utah chub on the growth of kokanees in six 80-m3 enclosures containing ambient zooplankton populations. Three kokanees and 0, 3, 6, 12, or 24 Utah chub were weighed and placed in each enclosure. After 21 d, fish were removed and kokanee growth was compared among treatments. Zooplankton biomass, chlorophyll-a concentrations, and temperature profiles were monitored during each test. In May 1992, no competitive interactions were observed; in June 1992, however, zooplankton biomass and kokanee growth declined significantly as Utah chub densities increased. The best predictor of kokanee growth was Daphnia pulex density, which explained 76% of the variance in kokanee growth. Differences in temperature and initial zooplankton biomass affected the strength of observed competition. Our results suggest that monitoring forage resources rather than nongame fish densities may provide a better framework for assessing competition among pelagic fish species.

Comparison of Catch per Effort and Removal Procedures for Sampling Stream Fish Assemblages

Abstract Methods used to estimate fish abundance in streams should be chosen based on the precision required by the study, the available time, and the number and kinds of species targeted. When entire assemblages of predominantly small, nongame fishes are to be sampled, most existing procedures have limitations. We compared estimates of species richness, abundance, and assemblage structure based on catch per effort (CPE) during a single tow-barge electrofishing sample versus intensive tow-bare electrofishing removal sampling procedures with block nets in paired, contiguous stations on nine streams in southern Wisconsin. Use of block nets had little effect on CPE during single upstream electrofishing passes; for stations approximately 35 times the mean stream width in length, the overall influence of fish entering and leaving the station appeared to be negligible. Estimates of abundance, based on total catch and based on the removal model, were higher in removal stations than in CPE stations. However, esti...

The roles of predation, competition, and exploitation in the trophic dynamics of a warmwater stream: a model synthesis, analysis, and application

We developed a trophic dynamic model of key populations and processes in the New River, West Virginia, to identify the mechanisms most responsible for maintaining food web structure. Key populations were represented by thirteen model components and were aquatic insects; age-1 and age-2 crayfish (three species); age-1 and age-2 hellgrammites (Corydalus cornutus larvae); non-game fishes; age-0, age-1, and adult smallmouth bass (Micropterus dolomieu); age-0, age-1, and adult rock bass (Ambloplites rupestris); and age-0, age-1 to age-3, and adult flathead catfish (Pylodictis olivaris). In this system, crayfish and hellgrammites are harvested to provide bait for the recreational fishery that extensively exploits the three predatory fish species. Predation and intraspecific regulation were represented with nonlinear algorithms, and linear terms represented fishery harvests. Interspecific competition among components occurred through predation on shared prey. Error analysis of the model suggested that predation was the most important mechanism in maintaining system structure (the disposition of biomass among system components). Further, the trophic relation between each component and its prey accounted for 34–64% of the variability in food web structure, whereas predation on each component explained 1–24% of food web structure variability. Therefore, so-called ‘bottom-up’ effects were more influential than ‘top-down’ effects. Interspecific competition and intraspecific regulation had secondary roles in maintaining New River food web structure, although intraspecific regulation was most important to aquatic insects, which were not predatory in our model. Both forms of competition are probably tempered by extensive predation and exploitation in the New River system. Exploitation was a secondary structuring agent to adult smallmouth bass, which experience a high rate of harvest in the New River.

Status of Freshwater Fishes of the United States: Overview of an Imperiled Fauna

Conservation biologists have begun a concerted effort to educate the public, resource administrators, and politicians about the decline of temperate ecosystems, including their fishes. The United States harbors the most diverse temperate freshwater fish fauna in the world with about 790 species represented, about 90% of which are nongame fishes. From a state-by-state perspective, diversity of fishes in the United States is concentrated in the South, primarily in Alabama, Kentucky, Georgia, Mississippi, Tennessee, and Virginia, each of which supports at least 200 native fish species. Endemicity of fishes is high in both the South and West; in the latter region, up to 70% of fishes in some drainages (e.g., Colorado River) are endemic. Imperilment apparently is not confined to particular taxonomic groups. Of the five most diverse fish families in the United States, total imperilment ranges from 7% in the Centrarchidae to 50% in nonanadromous salmonids and indicates widespread and pervasive degradation of aquatic habitats. Imperilment is most acute in areas of high diversity and/or endemicity (i.e., the southern and western states). States with 20 or more imperiled fishes include Alabama, Arizona, California, Georgia, Nevada, New Mexico, North Carolina, Oregon, Virginia, Tennessee, and Texas. Backlogs in listing species as federally threatened or endangered are most egregious (10 or more backlogged taxa) in Alabama, Georgia, Nevada, and Tennessee.

Ecology of metazoan parasites infecting Catostomus spp. (Catostomidae) from southwestern Lake Superior

Ecology of the parasite fauna of two abundant nongame fish species, Catostomus catostomus (longnose sucker) and Catostomus commersoni (white sucker), from southwestern Lake Superior was examined. White sucker harbored a total of 17 parasite species compared with 8 species in longnose sucker. Echinorhynchus salmonis and Neoechinorhynchus crassus were the most abundant helminths in both sucker species. The only parasitic copepod found in this study, Ergasilus nerkae, was more prevalent in longnose sucker. In white sucker, Glaridacris catostomi, Capillaria catostomi, Ergasilus nerkae, Allocreadium lobatum, and Isoglaridacris bulbocirrus showed fluctuations in prevalence on a seasonal basis. Several helminth species showed a high degree of microhabitat overlap in the gut (e.g., A. lobatum, G. catostomi, and Echinorhynchus salmonis). Helminths that exhibited a higher mean intensity in certain sections of the intestinal tract included I. bulbocirrus in the anterior portion of the gut and Capillaria catostomi in the posterior region of the gut.

Nesting Common Mergansers in Chihuahua, Mexico

While my collections suggest that the 1973 record of P. caprodes (Clark, 1975) was actually P. macrolepida, the lack of voucher specimens and recent nongame fish collections from Two Buttes Reservoir make it impossible to validate the identification of the 1951 record of P. caprodes. The status of P. caprodes as a component of the state's ichthyofauna will remain a question until a voucher specimen from Colorado is obtained. Neither P. caprodes nor P. macrolepida have been reported elsewhere in Colorado. All P. macrolepida collected by me were deposited in the ichthyological collection of the Fort Collins Section of the National Ecology Research Center, Fort Collins/Biological Survey (FC/BS). I thank T. R. Cummings, R. T. Muth, and L. H. Schrader for assistance with field collections, H. Fisher for permission to collect in Baker Lake, S. A. Flickenger for unpublished information on the 1973 putative record of P. caprodes, K. J. Kehmeier for facilitating acquisition of collecting permits and supplying fishery reports on Two Buttes Reservoir, M. M. Stevenson for verifying species identifications, and L. M. Page and D. L. Propst for reviewing a previous version of the manuscript.

Summer Feeding Habits of River Otter (Lutra canadensis) on the Mendocino National Forest, California

The diet of otters was studied over one season on the Mendocino National Forest in northern California. Undigested prey remains were analyzed from 94 otter scats collected between 18 April and 29 August 1982. Fish were found to be the predominant food, occurring in 89.4% of the scats with a mean volume estimate of 63%. Fishes consumed were primarily catostomids and salmonids. Crayfish and snakes were common prey items as well. Insects were often found in otter scats, but repre- sented little volume. Bird, turtle, frog, and snail remains occasionally were found in the scats. Feeding habits of the North American river otter (Lutra canadensis) have received considerable attention in the literature of wildlife biology, with special emphasis often placed upon the relative proportions of game and non-game fish species taken. One approach has been to study the remains of prey in stomachs or intestines of otters taken by commercial trappers (Lagler and Ostenson 1942; Ryder 1955; Hamilton 1961; Toweill 1974, Lauhachinda 1977). While this method permits relatively accurate esti- mations of prey size and numbers (Lagler and Ostenson 1942), it requires grave com- mitment on the part of the otter. In areas where otter are fully protected, analysis of scats is a workable alternative to digestive tract analysis (Trautman 1936; Wilson 1954; Greer 1955; Sheldon and Toll 1964; Knudsen and Hale 1968; Modafferi and Yocom 1980; Melquist and Hornocker 1983). Scat analysis has certain inherent shortcomings. First, the digestive process renders even some hard parts less identifiable. Second, hard indigestible portions of prey are over- represented compared to soft parts. Mech ( 1970) hypothesized that because of this, smaller prey with greater surface area:volume ratios would be over-represented in scats of carnivores. Floyd et al. (1978) tested this idea with captive wolves and found that smaller animals were indeed over-represented in frequencies of remains in scats. Last, assessment of feeding habits by frequency of occurrence in scats has been shown to be inherently biased, over-estimating food items occurring in low proportions and under-estimating at high proportions (Lockie 1959). Because of this last problem, it has been recommended (Korschgen 1980) that some estimate of volume or weight be included with frequency of occurrence data in all feeding habits studies. Lagler and Ostenson (1942) estimated volumes of otter stomach contents, and Modafferi and Yocom (1980) measured volumes of food items found in otter scats. This communication presents feeding habits information obtained from river otter scats collected in 1982 on the Mendocino National Forest in northwestern California. Data are expressed as percent frequency of occurrence and mean percent estimated volume.

Relations of Physical Habitat to Abundance of Four Nongame Fishes in High-Plains Streams: A Test of Habitat Suitability Index Models

Abstract We examined relations between habitat variables and biomasses of white sucker Catostomus commersoni, creek chub Semotilus atromaculatus, longnose dace Rhinichthys cataractae, and common shiner Notropis cornutus from data collected at 29 sites in the Horse Creek drainage of eastern Wyoming. Few of the habitat variables that have been used in habitat suitability index (HSI) models were correlated with the biomass of the four species. Also, composite HSI scores were not correlated with the biomass of the four species. However, abundances of these species were related to other habitat features that we measured and analyzed by correlation and multiple-regression analysis. White sucker biomass was correlated with main-channel run habitat, shade, turbidity, water temperature in August, and large woody debris. Creek chub biomass was related to the coefficient of variation (SD/mean) in current velocity and to submerged aquatic vegetation, average current velocity, and main-channel pool habitat. Longnose d...

Spatial, seasonal and diel distribution of fishes in a California reservoir dominated by native fishes

During 21 months of sampling with various techniques, we captured 24 species of fish in Britton Reservoir. Nine species comprised over 96% of the number of fish captured and approximately 88% of the biomass. Five native non-game species accounted for over 77% of the catches. The native non-game fishes have maintained large populations in the reservoir despite continued introductions of non-native species. Two sources of non-native species exist. The first is the introduction of exotic species directly into the reservoir during fish-stocking programs. The second is the continuous movement of non-native fishes into the reservoir from large populations which reside in a major tributary of the reservoir. Factors responsible for the large number of native fishes are: management of the reservoir for hydroelectric generation; temperature regime; reservoir morphology. The fish community structure is stratified along two axes: upper basin/lower basin and inshore/offshore. Most of the 24 species were found inshore: 14 species were found offshore. Four of the native non-game fishes were most abundant in the upper basin: three introduced non-native fishes were most abundant in the lower basin of the reservoir. The offshore community was dynamic on a daily and seasonal basis.

Regulatory Theory and State Land-Use Regulation: Implications from Florida's Experience with Growth Management

I. Congressional Record, December 20, 1979, pp. S19475-6. 2. There never has been any limitation by law or regulation that required federal aid wildlife funds to be used for game species, but the program has been directed that way largely by assumption, based on the fact that hunters were being taxed, according to Durwood L. Allen in Enjoyment of Wildlife, in H. P. Brokaw, ed., Wildlife and America (Washington, D.C.: Council on Environmental Quality, 1978), p. 36. 3. The term is used throughout this report to refer to wildlife-oriented activities which do not involve the removal or intended removal of animals from their natural habitats. Use of this term is not meant to imply that nonconsumptive activities have no impacts on wildlife resources. The term is a useful and widely adopted means of categorizing an important group of human activities involving wildlife resources. Also, while the term nonconsumptive is used for describing certain categories of human behavior, it should not be confused with game/nongame distinctions which describe legal designations for kinds of wildlife. 4. See U.S. Department of the -Interior, 1980 National Survey of Fishing, Hunting, and Wildlife-Associated Recreation (Washington, D.C.: U.S. Department of the Interior, Fish and Wildlife Service, 1982) for a complete description of the survey results. 5. David S. Brookshire, Larry S. Eubanks, Alan Randall, Estimating Option Prices and Existence Values for Wildlife Resources, Land Economics 59(1) (February 1983): 1-15. 6. Nongame Newsletter, 1982 1(3): 1. 7. Potential types of equipment were identified in a study conducted for the Council on Environmental Quality in 1975 by the Wildlife Management Institute entitled Current Investments, Projected Needs and Potential New Sources of Income for Nongame Fish and Wildlife Programs in the United States (Washington, D.C.). 8. It should be noted, however, that one of the most frequently cited sources of birdfeeding estimates (De Graaf and Payne, 1975) estimated total annual retail sales of feed in 1974 to be $170 million. But, Ferris (1980) has mentioned estimates of up to $340 million in sales. R. M. DeGraaf and B. R. Payne, Economic Values of Nongame Birds and Some Urban Wildlife Resource Needs, Transactions of the North American Wildlife Natural Resources Conference 40 (1975): 281-287. L. H. Ferris, A Little Something for the Birds, Yankee Magazine 44(2) (1980): 94-100.

Responses of Fish Populations in the North Fork of the Feather River, California, to Treatments with Fish Toxicants

Abstract Two reaches of the North Fork of the Feather River in California were poisoned with rotenone to reduce nongame fish populations, one in 1977 and the other in 1981. Both reaches had been poisoned 10 years earlier as well. Standing crops, population structure, and growth rates were determined for rainbow trout (Salmo gairdneri, Sacramento sucker (Catostomus occidentalis), Sacramento squawfish (Ptychocheilns grandis), hardhead (Mylopharodon conocephalns), smallmouth bass (Micropterus dolomieni, and riffle sculpin (Cottns gnlosns) from fish killed in test sections. The nongame fish populations recovered from the previous poisoning operations, although the unusual age structure of the sucker population (skewed to large old individuals) in the 1977 section was attributed to the earlier treatment. In the reach treated in 1977, the rainbow trout population was small and the growth rates of smallmouth bass and nongame fishes were slow compared to populations in other streams. The section treated in 1981 h...

Evidence Against Competition between Trout and Nongame Fishes in Stampede Reservoir, California

Food habits of exotic brown trout (Salmo trutta) and rainbow trout (Salmo gairdnerii) and of two native nongame fishes, tni chub (Gila bicoior) and Tahoe sucker (Catostomus tahoensis) were investigated in a California subalpine reservoir. Competition for food resources between trout and native fishes is often cited as the cause for decreased salmonid angling success. The data indicated a minimal dietary overlap between the primarily limnetic-feeding trout and the benthic-feeding sucker, even when food resource levels decline in early fall. Although both trout and tui chub are limnetic feeders, they appear to partition resources sufficiently to avoid competition. Trout are highly specialized feeders on Daphnia and dipteran pupae (displaying significantly greater selectivity than nongame fishes) until reaching a piscivorous size (>300 mm). Once trout change over to a piscivorous diet, they not only display minimal food overlap with nongame fishes, but also feed heavily on small tui chubs and suckers. Although competition for food between trout and native fishes is unlikely, inter-specific competition between the morphologically and behaviorally similar brown trout and rainbow trout is likely.

Piscivority by Stocked Brown Trout (Salmo trutta) and Its Impact on the Nongame Fish Community of Bottom Creek, Virginia

The magnitude of fish consumption by brown trout (Salmo trutta) was assessed by experimentally stocking large (> 280 mm) and small (< 280 mm) brown trout in separate sections of a Virginia stream. Large brown trout ate five species of fish consistently during the May–November, 1979, experimental period; by November, every trout stomach examined contained fish remains. Small trout rarely ate fish. Effects of fish consumption were apparent in trout growth and in abundance of prey species. Large trout grew 9.4% in length and 21.3% in weight, whereas small trout grew 4.5% in length and 4.7% in weight. Abundance of the major prey species, torrent sucker (Moxostoma rhothoecum), decreased between April and October in the stream section containing large trout, but remained constant in a comparable reference section; estimates of total consumption of torrent suckers by brown trout accounted for a large portion of the decrease in abundance. Predation on torrent suckers was selective for smaller individuals. The field experiment indicates that stocking large-sized brown trout may enhance growth and survival of brown trout, but that standing crops of nongame species are likely to decline.Key words: brown trout, nongame fishes, predation, stocking strategy, stream ecology

Distribution of total mercury in the fishes of Lake Oahe

In 1971, a joint Federal-State survey was conducted to investigate the total mercury content of fish and sediment in Lake Oahe, South Dakota. Average total mercury concentration of 225 fish flesh samples was 0.27 mg kg −1; game fish samples averaged 0.31 mg kg −1 and nongame fish samples averaged 0.22 mg kg −1. Frequency distributions of total mercury concentrations in the fish are presented by fish species and sampling location. Data include total mercury analyses of 43 sediment samples.

Food Habits of Otters in the Great Lakes Region

Food items were identified in digestive tracts from otters (Lutra canadensis) taken by trappers during February, March, and April over a period of 6 years in Wisconsin, Michigan, and Minnesota. In addition, scats of Wisconsin otters from all seasons of the year were examined for food remains. Fish, particularly non-game fish, were the main prey species. Game fish (including trout) occurred infrequently. Crayfish, frogs, and aquatic insects were other important foods. In the early 1950's some Wisconsin sportsmen were vociferously condemning the otter as a destroyer of trout and other game fish. A second public faction maintained that otters were not destructive and should be completely protected from trapping. To evaluate these charges, an investigation of otter food habits in Wisconsin was under-

Utilization of Hatchery Fish

Washington State Game Department has been pushing vigorously aprogram of lake rehabilitation. Briefly, the program consists of treating lakes chemically to eradicate existing undesirable fish populations and replanting with desirable game fish. In all, 209 lakes have been treated so far. These have ranged in size from small ponds of 5 acres or less to lakes of nearly 900 acres. The primary purpose of the program is to provide the best fishing possible. Economically it has proved particularly successful. In untreated lakes having mixed populations of both game fish and nongame fish, it was found that fair fishing could be provided by planting trout that were legal sized (6 inches) or larger. However, these plants were very costly and caused considerable controversy among fish men as to whether they could be justified. Without allowing for capital-investment charges, interest, or depreciation, it costs about 79 cents across the board

The Opercular Bone as an Indicator of Age and Growth of the Carp, Cyprinus Carpio Linnaeus

As part of an investigation of the non-game fish resources of Utah, a study of the age and growth rate of the carp was instituted. A preliminary investigation indicated that the opercular method was superior to several other methods of determining age and growth. Age and growth were calculated from the opercular bones of 330 carp collected at Ogden Bay Refuge in 1950–51. Distances to annuli were measured directly. The relationship between the posterior radius of the opercular bone and the standard length of the carp was curvilinear. Past growth was calculated with a logarithmic nomograph. Expected number of annuli on opercular bones of known age carp, agreement of ages assessed by length frequency modes and those assessed from opercular bones of the same fish, agreement of ages assessed by empirical length frequency modes with modes formed by pooled calculated lengths, agreement between ages assessed by scales and opercular bones, and increase in age with increase in size were accepted as evidence of the validity of the opercular method. Decrease in growth rate at any year of life for successive age groups is attributed to a gradual change of the environment.

Snaring Through the Ice for Nongame Fish in West Virginia

Snaring Through the Ice for Nongame Fish in West Virginia

A Study of Populations of Fish Based on Catch-Effort Statistics

The Department of Lands and Forests of the Province of Ontario conducts an annual program of netting small-mouth black bass (Micropterus dolomieu) from waters in the Province where these fish are abundant, but small. The fish are transported to waters where angling is reported to be poor. In the course of this work many non-game fish are taken in the nets. These are destroyed, since it is believed to be desirable to exert the same fishing pressure on all species present in order that the relative population levels in the waters will not be seriously influenced. The present paper is an attempt to use the catcheffort data of three such fisheries to assess the populations of the lakes. O'Reilly Lake, Davern Lake and Little Silver Lake, in Eastern Ontario, north of the Kingston-Gananoque area are dealt with here. In accordance with our usual method, trap nets were set in each lake, and catches recorded from day to day. It was found that a net set in a likely looking spot would fish well for a few days, when catches would drop off sharply. The net was then moved, in some cases only about 200 yards, and high catches would again be reported. The entire impression was one of exploitation of a series of local populations, usually in sheltered bays. The setting of the trap net is limited to rather shallow water (up to ten feet) and no effort at exploitation of those areas where shore water was over this

The Eastern Belted Kingfisher, Megaceryle Alcyon Alcyon (Linnaeus), in Relation to Fish Management

The kingfisher is the most common and universally distributed bird predator of fish in Michigan. Its principal migration routes are along the Great Lakes shores. Nesting territories are established along streams and lake shores; they are usually larger in the former than in the latter. The kingfisher is diurnal in its feeding with three peaks of activity–morning, afternoon, and early evening. First feeding of fledgelings is on insects; this food is followed by crayfish, then by fish. Fish eaten average about 2.3 inches in length and at fish hatcheries are mostly the species being propagated. On natural waters the food consists mostly of non-food and non-game fishes and crayfish. Predation pressure varies with season and within season according to weather, nest distribution, and environmental suitabliity of waters for feeding activity. Because of their feeding proclivities, it is undesirable to have kingfishers about fish hatcheries and rearing stations. At present, general control on natural waters is not biologically justified.