Large Perch Research Articles

Ruffe From the Former USSR: Variability Within the Largest Part of its Natural Range

This paper reviews current data on the ruffe, Gymnocephalus cernuus L., its range, variability of its meristic and morphometric characters, diet composition and trophic relationships, habitats, behavior, growth, reproduction, and abundance. Ruffe, a monotypic species, is found from the Baltic Sea to the Kolyma River. Recent evidence extends its distribution as far as the Arctic coast both in Europe and Asia. In the south, the range is restricted by the Caucasus in Europe, and in Asia by the Aral Sea basin and upper reaches of several large Siberian rivers. Ruffe usually have a narrow home range. Their seasonal migrations are related mainly to reproduction. In lakes and reservoirs, ruffe are found everywhere from shallow to the deepest zones. In rivers, they prefer sites with slow current. Ruffe show flexible foraging, breeding, and migratory behavior. Adults compete with common bream, roach, and benthivorous whitefishes, and are the prey of pikeperch, burbot, pike, large perch, and eel. The age of maturation is similar (2 to 3 years, sometimes 1 year) from the northern to southern areas. Fecundity tends to increase from north to south. Daily specific growth rate is rather constant everywhere; the fastest growth was observed in the newly-impounded reservoirs. Ruffe variability to a larger extent depends on local ecological situations rather than on latitudinal factors. Attempts to control ruffe populations with small-mesh seines were unsuccessful and only caused a reduction in average age of populations. Introduction of some piscivorous fishes (eel, pikeperch) was more efficient.

Size‐Specific Interactions in Lake Systems: Predator Gape Limitation and prey Growth Rate and Mortality

To study the effects of different predators on the behavior and dynamics of their prey, we compared the performance of perch (Perca fluviatilis) and the abundance of their prey resource in four lakes with two different types of piscivory. In two of the lakes, perch were the only fish species present and piscivory was restricted to cannibalism. In the other two lakes, perch co—occurred with piscivorous pike (Esox lucius). Pike grow to larger sizes and can capture larger prey than piscivorous perch. Therefore, perch reach a size refuge earlier in the lakes without pike. Perch in the lakes lacking pike used both the epilimnion and hypolimnion habitats of the lakes, and a high proportion of the perch occurred below the thermocline. In contrast, perch in the lakes with pike were mainly captured along the littoral zone and were never captured below the thermocline. This difference in habitat use was reflected in different diets of perch in the different lakes. Perch in the lakes with pike were also less abundant than those in the lakes lacking pike and the growth rates of individual perch and the densities of predator—sensitive prey (pelagic and littoral) were higher, indicating that the presence of pike resulted in decreased intraspecific competition in perch. Evidence for a behavioral response to predation risk was found in 1 + (1 yr old) perch, which was suggested to be due to predation risk from both larger perch and pike. It is hypothesized that the use of the cold—water hypolimnion habitat by perch in the lakes lacking pike was a response of perch to reduce metabolic demands under conditions of severe resource limitation. Differences in gape limitation between predators species are suggested to have major effects on size—dependent mortalities and growth rates in prey and thereby on overall community dynamics. Evidence for this latter effect was observed in differences in zooplankton size structure between the lakes with and without pike.

Effects of temperature on life history variables in perch

Population structure, recruitment, mortality, life expectancy, age at maturity, gonad development, fecundity, net reproductive rate and energy storage were studied in a perch population exposed to thermal discharge. The experiment was conducted during 1978–1990 in an artificial enclosure at a nuclear power plant on the Baltic Sea coast. Abundance increased after the plant started operating, although the proportion of larger perch dropped to a low level. Recruitment improved, but adult mortality increased. This effect was accentuated as the fishes matured very early and at a very small size, reducing their ability to support a growing gonad in high winter temperatures. During the spawning period, condition dropped to very low levels accompanied by increased mortality. Surviving fish delayed the next spawning by one or more years and reduced their fecundity. Body condition thus improved in large perch at the end of the study period. Life‐time fecundity was reduced, and reproductive performance shifted to youner ages.

Influence of temperature and size of females on the timing of spawning of perch, Perca fluviatilis, in Lake Geneva from 1984 to 1993

The influence of temperature and the size of reproducing females on the timing of spawning of perch in Lake Geneva has been studied for 10 consecutive years (1984–1993) by means of artificial spawning substrates. The clutch of perch is an egg ribbon with a width proportional to the size of the reproducing female, so that the size structure distribution of the female population can be estimated from measurements of the width of the egg ribbons. The survey of egg-ribbon size revealed a succession of 3 cycles (period of increasing mean size followed by a sharp decrease) lasting 3, 3 and 4 years which were due to the occurrence of 3 strong year classes born in 1982, 1985 and 1988 respectively. This phenomenon can be explained by the effect of intraspecific predation exerted by strong year classes on the offspring of the 2 following years rather than by fluctuations in the success of reproduction in relation to climatic changes. In Lake Geneva, perch spawn in May. The water temperature exerted only a minor influence on the date of the beginning of the spawning period but had a greater effect on its intensity. A rise in temperature in May stimulated spawning while bad weather decreased spawning intensity. The larger perch had a tendency to spawn later than the small ones. The date of the mid-spawning period was well correlated with the yearly mean width of perch egg ribbons but no correlation could be detected between it and the water temperature.

Distribution of perch (Perca fluviatilis L.) during their first year of life in Lake Constance

The distribution and behaviour of larval and juvenile perch (Percafluviatilis L.) were studied for two years in large, deep Lake Constance. After hatching larvae were transported by water currents to the open water. The majority of larvae remained in the pelagic zone for about one month. In both years, their return to the littoral zone coincided with the decline of pelagic zooplankton abundance. After returning to the littoral zone, juveniles stayed among submerged macrophytes within 5 m depth and lived apart from larger perch which lived at depths of 6-20 m. By late summer, juveniles changed their distribution pattern: during the day they stayed intensively close to piers and ports, but increased their swimming activity at dusk, cruising among shallow and deep waters and feeding on zooplankton, and rested on the bottom at night. This behaviour appears to be related to the decrease of inshore food resources and to the presence of predators in deeper water. 0 + perch left the littoral zone and moved into deep waters when autumnal mixing began in late October. They overwintered near the bottom at depths of more than 30 m. During most of the year, juvenile and adult perch were separated from each other. But as soon as they occupied the same habitat, the occurrence of cannibalism increased.

Changes in Abundance of Two Percids,Perca fluviatilisandGymnocephalus cernuus, along a Productivity Gradient: Relations to Feeding Strategies and Competitive Abilities

Relative abundances of perch (Perca fluviatilis) and ruffe (Gymnocephalus cernuus) were studied in eight lakes ranked along a gradient of increasing productivity. The diets of perch and ruffe in relation to food resources were quantified over a 5-mo period in one lake of moderate and one lake of high productivity. The abundance of perch decreased and that of ruffe increased along the productivity gradient. Large perch ate fish over the whole season in the more productive lake, but rarely ate fish in May and June in the less productive lake. All size classes of ruffe fed mainly on macrobenthos in both lakes. The diversity of macrobenthos was higher in the lake of low productivity, as was the diet breadth of ruffe. The abundance patterns of perch and ruffe are likely related to the simultaneous effect of increasing prey abundance and decreasing light penetration with increasing productivity. Furthermore, the abundance of perch is likely affected by increasing interspecific competition and that of ruffe by decreasing predation pressure as productivity increases.

The Effects of Resource Availability and Distribution on Size Class Interactions in Perch, Perca fluviatilis

The relationships between foraging efficiencies and prey species and size were investigated in laboratory and field studies of the perch, Perca fluviatilis. When fed Daphnia in the laboratory, small perch (one year old, 1+) had both a higher capture rate and a lower handling time than large perch (two year old, 2+). When perch were fed Cyclops no significant effect of age class on capture rate was found. Large perch had a higher capture rate than small perch when feeding on chironomids and Sialis and a lower handling time when feeding on Sialis. Although the capture rate of chironomids at low prey densities was greater for 2+ perch than for 1 + perch, the lower metabolic demands of 1 + perch enabled them to obtain a higher net energy intake. Due to their lower metabolic demands and higher capture rate when fed cladocerans in the laboratory, small perch were predicted to have a higher competitive ability in the pelagic habitat of lakes. This prediction was verified in a field experiment as 1 + perch had both a higher growth rate and a greater ability to withstand resource depression. When alone 1+ and 2+ perch utilized the same food resources, but when they coexisted, their diets differed. The superior competitive ability of 1+ perch in the pelagic habitat is probably responsible for the previously observed age-class, habitat segregation that occurs in the summer during periods of low food availability. The tendency for perch populations to become stunted is most likely due to the large pelagic and small littoral zones in many lakes as well as the higher temperatures during the summer. Both of these factors favour smaller perch.

Competition in Umbra-Perca fish assemblages: experimental and field evidence.

One potentially important effect of interspecific competition in freshwater fish communities is to increase predation intensity from gape-limited piscivores by lowering growth rates of prey species. We investigated the operation and consequences of competition between central mudminnows (Umbra limi) and yearling yellow perch (Perca flavescens) in a system where size-limited predation on mudminnows by larger perch is a principle structuring mechanism. During laboratory experiments in which mudminnows foraged for patchily-presented food in the presence and absence of yearling perch, the food intake of mudminnows decreased at both the population and individual-fish levels when perch were present. Mudminnows were neither less active nor did they occupy lower-quality food patches in the presence of perch; exploitation competition, rather than interference or predator avoidance, appeared responsible for reduced feeding success. To assess effects of competition in the field, we examined size distributions and condition factors of yearling mudminnows and perch in small Wisconsin lakes having mudminnow-only and mudminnow-perch assemblages. Yearling mudminnows were smaller and in poorer condition in an assemblage composed (by mass) of 45% yearling perch than in two mudminnow-only assemblages. Conversely, yearling perch were larger and in better condition when the mudminnow-perch assemblage contained only 45% perch then when it contained 92% perch. Our experimental and field results indicated that an asymmetrical competitive relationship could contribute directly to the interspecific population dominance of perch over mudminnows in Umbra-Perca assemblages through reduced food intake, growth, and condition of mudminnows, and indirectly through increased vulnerability of mudminnows to size-limited predation.

Size-Limited Predation, Winterkill, and the Organization of Umbra–Perca Fish Assemblages

We compared population densities and size structures of central mudminnows (Umbra limi) occurring with and without yellow perch (Perca flavescens) in six small lakes in northern Wisconsin over a 6-yr period. Our observations suggested that a size-dependent predator–prey interaction was a major mechanism organizing these assemblages. Densities of mudminnows cooccurring with perch averaged 12% of populations in mudminnow-only lakes. Large mudminnows (≥76 mm total length) predominated in populations with perch whereas smaller fish predominated in single-species assemblages. Following severe winterkills of adult perch in two lakes, mudminnow densities increased significantly due to high survival and recruitment of yearlings. Increases in small mudminnows lasted only a year: densities and size distributions returned to prewinterkill patterns when perch that had survived winterkill attained lengths >13 cm. To examine the role of size-limited predation, we performed an experiment in 2000-L tanks, varying the initial size distributions of mudminnows and perch and measuring size-specific survival among mudminnows. Predation in the experimental populations was greatest when large perch (121–180 mm) were with populations of predominantly small mudminnows (<76 mm); smaller perch (114–132 mm) were significantly less successful as predators whereas large mudminnows were significantly less vulnerable to predation by even large perch. Despite this interaction, central mudminnows coexist at low densities with yellow perch; possible factors permitting coexistence are fish sizes and spatial and structural refuges.

A Review of Research on the Limnology of West Blue Lake, Manitoba

An interdisciplinary research program on the West Blue Lake ecosystem is reviewed. The composition, seasonal occurrence, abundance, and primary productivity of the phytoplankton are reported. In spring "net" phytoplankton diversity and abundance were highest with diatoms predominating. In summer Anabaena spiroides and Aphanizomenon flos aquae were a major component. During winter both cell numbers and species diversity declined. Cyclotella bodanica became dominant. Average summer phytoplankton primary productivity approximated 320 mg C m−2 day−1 in both 1971 and 1972. Average daily estimates (exclusive of zooplankton) of organic carbon in the euphotic zone during summer periods in 1971 and 1972 were, respectively, 5 and 8 g C m−2.Kinetic parameters for the bacterial uptake of 11 dissolved organic substrates are reported. Values Vmax ranged from 0.003 mg C m−3 h−1 for formic acid to 0.115 mg C m−3 h−1 for lactic acid; turnover times from 8 h for malic acid to 950 h for glycolic acid, and (Km + S) values from 0.288 mg C m−3 for malic acid to 47.883 mg C m−3 for glucose. A relation between Vmax values and plated bacterial counts is described for six organic acids. Evidence for proliferation and adaptation of bacteria in sample bottles is presented and the absence of photoheterotrophy described. Potential bacterial production during the summer of 1972 ranged from 18.24 mg C m−2 day−1 to 67.44 mg C m−2 day−1. The relationship between this production and temperature (Q10 = 3.129) is described. "Filtration effect," as a source of error, in measuring glucose uptake is probably an artifact.Generally, Cyclops bicuspidatus was more abundant than Diaptomus siciloides. Both were relatively scarce in summer. Daphnia pulicaria were usually most abundant in spring and early summer, and persisted at low levels during winter. Largest animals (over 2.0 mm long) with high relative caloric content [Formula: see text] predominated in fall, winter, and early spring when reproduction was minimal. No fish species reside permanently in the pelagic zone of West Blue Lake, but age 0 fry of Perca flavescens inhabited the epilimnion during July and early August and fed almost exclusively on D. pulicaria. In contrast, age I and older perch consumed a variety of, principally, littoral organisms. Walleye, Stizostedion vitreum vitreum, over 25 cm in length put on most of their annual growth in length and weight during the summer, when maximum production also occurred. Perch fry and larger perch were an important food for walleyes.

Lac Léman: Effects of Exploitation, Eutrophication, and Introductions on the Salmonid Community

Review of 14 years of data concerning the geographic and hydrographic characteristics of Léman show that this lake is in the process of eutrophication: nutrient levels are increasing, oxygen levels are decreasing in the deep waters, and the algal flora has changed. The effect of the current warming of the climate on its evolution is taken into consideration.Since 1900 the fishing regulations of the Swiss and French have been dissimilar. Excessively small size limits and at certain times the abusive use of nets have repeatedly led to a reduction of the most valued species.French catch data, covering more than 70 years, reveal fluctuations which reflect biological disturbances due primarily to overexploitation and also to eutrophication. Landings have increased but value has decreased.Numerous introductions have been made purposely or accidentally. Certain of these species have had deleterious effects (sticklebacks) and some beneficial (introductions of a new population of coregonines after the extinction of the indigenous species).Some aspects of the biology of the most valued salmonids (Salmo trutta, Salmo gairdneri, Salvelinus alpinus) have been shown as well as the results of attempts to repopulate them using pisciculture and marking. Plantings of rainbow trout along the shoreline during summer gave best results (percentage return and growth being most important), although their reproduction seems to be doubtful.Overexploitation of coregonines followed by that of perch (Perca fluviatilis) has left roach (Rutilus rutilus) to inhabit all the central zone of the lake. This valueless species is favored by eutrophication and is thus able to utilize plankton without undergoing competition from coregonines and young perch, or predation by larger perch. No fishing profits are derived from the invasion of the lake by roach.

A New Type of Metacercarial Cyst of the Genus Apophallus, from the Perch, Perca flavescens, in Minnesota

A new type of cyst containing a metacercaria with the characters of the genus Apophallus, but differing considerably from any Apophallus cysts previously described, was found imbedded in the musculature of the common perch, Perca flavescens, in northern Minnesota. These cysts were present in all of 30 perch examined from Lake Itasca and in a single large perch, about 12 inches in length, examined from Leech Lake. The fish from the first lake varied from two to eight inches in length. A few cysts were also found in one of a number of minnows, Notropis sp., from Lake Itasca, but they were not found in Fundulus diaphanus, Esox lucius, Stizostedion vitreum or Ambloplites rupestris, although several of each were examined. Following is a description of the cysts and of the contained metacercaria, for which the name Apophallus itascensis is proposed, a report of negative experimental feedings, and a discussion of the relation of this parasite to other species of the genus. Grateful acknowledgement is made of the assistance given by Dr. Asa C. Chandler in the course of this study.

Experimental Studies with Pasteurella Tularensis in Fish *

Summary and Conclusions Six species of fish, black bullhead (Ameiurus melas), black crappie (Pomoxis nigro-maculatus), large mouth bass (Huro salmoides), northern pike (Esox lucius), yellow perch (Perca flavescens), and rainbow trout (Salmo gairdnerii irideus) was injected intraperitoneally with 1 ml of a 48 hour culture of Pasteurella tularensis. All of the fish were negative from 1 to 10 days after inoculation as determined by guinea pig inoculation, serum agglutination tests, and attempts at direct cultural isolation of the organism. Bullheads fed infected liver also remained negative. These negative findings indicate that certain fish are not susceptible to tularemia and, consequently, would not represent a reservoir of the disease and a public health menace.