摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f77-207

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f77-208

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Two phyletic lines are present in the Percidae: the Percinae, in which the anteriormost interhaemal bone is much larger than the posterior ones and the anal spines usually are well developed, and the Luciopercinae, in which the interhaemal bones are of uniform size and the anal spines are poorly developed. Parallel evolution has produced in each subfamily small, benthic, rheophilic forms with depressed or terete bodies and reduced or vestigial swimbladders. This differentiation is shown by dividing each subfamily into two tribes. Within the Percinae, the Etheostomatini (Percina,Ammocrypta, andEtheostoma) are interpreted as derivatives of the Percini (Perca,Gymnocephalus[=Acerina], andPercarina). The North American speciesPerca flavescensis distinguished from the Eurasian speciesP.fluviatilisandP.schrenkion the basis of the more posterior position of the predorsal bone. In the Luciopercinae, the Romanichthyini (Zingel[=Aspro] andRomanichthys) have evolved from the Luciopercini (Stizostedion[includingLucioperca]).Key words: Percidae, systematics, zoogeography, evolution

ISSN:0706-652X    

DOI:10.1139/f77-209

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Perca fluviatiliswas introduced into Australia during the nineteenth century. Its extensive distribution in Australia and the range of climatic and topographic conditions over which it occurs make it possible to distinguish the roles of high temperature, breeding conditions, and flow characteristics in rivers in limiting the spread of the species. By extrapolation the distributional limits of the species throughout the world can be largely explained and, by analogy, those of the closely related speciesP.flavescensin North America. A model of a fish life cycle arising out of knowledge ofPercalife cycles is presented as a possible tool for clarifying and predicting the success or failure of species introduced into new environments.Key words: Percidae,Perca, zoogeography, life history, introduction in Australia, predictive model, management, Eurasian perch

ISSN:0706-652X    

DOI:10.1139/f77-210

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

In the sauger,Stizostedion canadense, the tapetum lucidum of the retina was found to be more highly developed than in the walleye,S.vitreum vitreum. The tapetum is uniformly distributed throughout the sauger's eye, whereas it reaches a comparable development only in the ventral region of the walleye's retina. Other structural differences also suggested that the sauger's retina is more sensitive to light than the walleye's. In both species, photomechanical changes in response to light- and dark-adaptation were restricted to the retinal epithelial pigment (melanin) and the rods. Electroretinographic recordings appeared to be correlated with the differences in tapetal development and habits of the two species.Key words: Percidae,Stizostedion vitreum vitreum,S.canadense, light intensity, retinal structure, histology, electrophysiology, behavior

ISSN:0706-652X    

DOI:10.1139/f77-211

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

A review of the literature indicated contrasts in retinal structure and function between perches (Percaspp.) and pikeperches (Stizostedionspp.). Foremost among these were differences in size and distribution of rods, size and shape of cones, extent of retinomotor responses, possession or lack of reflecting material, and relative concentrations of melanin. The perches are primarily active by daylight, whereas the pikeperches are most active during twilight or at night. The coincidental occupancy of shoal areas by yellow perch (Perca flavescens) and walleye (Stizostedion vitreum vitreum) at twilight is related to decreasing visual acuity of the former and the approach of optimum visual performance in the latter species. On this basis the two species have a classic predator–prey relationship.Key words: histology, light,Percasp., photopic vision, predation, retina,Stizostedion vitreum vitreum, symbiosis, tapetum lucidum

ISSN:0706-652X    

DOI:10.1139/f77-212

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

All facts when ordered and synthesized with previously published information suggest that light is the principal abiotic controlling variable of the environment that determines temporal and spatial dimensions of feeding and reproduction in the walleye,Stizostedion vitreum vitreum. Underwater observations during the day revealed that adult walleyes were active in turbid regions of a lake but rested in contact with the substrate in clear-water regions. In the latter instance physical shelter served to shield the eyes of the walleyes from the ambient light. An inverse relation was noted between numbers of walleyes sighted per hour of transect swum and transparency levels of the water. In experimental angling during the open-water season, the total number of walleyes captured and the catch per unit of effort were positively related to illuminance levels. Winter angling through the ice showed a similar relationship, though at percentage light transmission levels one order of magnitude lower. Percentages of walleyes captured perincrement during openwater at dusk were positively related to percentage decrease in illuminance for the same time intervals and inversely related to absolute levels of illuminance. Other authors have determined that nuptial activity also, and hence reproduction, is governed by variations in the ambient light regime.Key words:Stizostedion vitreum vitreum, walleye, light, behavior, photopic vision, tapetum lucidum, turbidity, preferred habitat, scotopic vision, feeding pattern

ISSN:0706-652X    

DOI:10.1139/f77-213

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The early development of the lateral-line systems in Eurasian perch (Perca fluviatilis) and the ruff (Gymnocephalus cernua) is described and related to development of behavior patterns characteristic of the two species. Perch are active pelagic predators for whom vision is of greatest importance in obtaining food, whereas ruff are benthophages of slow-flowing waters and typically obtain their food as solitary ambush predators for whom the highly sensitive lateral-line system is extremely important. The less developed system of the perch seems to match its greater ecological plasticity.Key words: Percidae,Perca,Gymnocephalus, lateral line, development, behavior, sensory organs

ISSN:0706-652X    

DOI:10.1139/f77-214

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

A review of literature onPerca fluviatilisandP.flavescensindicated one difference (in the position of the predorsal bone) sufficient to maintain their separateness as species. Otherwise they are overwhelmingly equivalent biologically. Their distributions are limited by the same effects of temperature, current speed, salinity, and dissolved oxygen. They are similar in gonadal development and age at first maturity; in the effects of water temperature and latitude on spawning time, and of environmental fertility on fecundity; in spawning behavior, fecundity, and the course of larval development. Growth capacities are similar and their expression subject to population density and temperature in the same way. Both species are adapted to a diet of small live animals, but will take whatever is available; cannibalism is characteristic, and may begin at the same early feeding stage. The two species show similarities in diurnal periodicity of feeding and in total food consumption. They also have the same pattern of development of light responses, of schooling, of activity and of daily and seasonal migrations. Within the fish community they fulfill the same role as converters of invertebrate foods into a form suitable for consumption by terminal fish predators, especiallyStizostedionspp., influencing the population dynamics of their predators in similar ways.Key words: Percidae, morphology, physiology, ecology,Perca, life history, growth, reproduction, yellow perch, Eurasian perch

ISSN:0706-652X    

DOI:10.1139/f77-215

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

A review of the literature indicated that pikeperch (Stizostedion lucioperca) are generally more tolerant than walleye (S.vitreum vitreum) of a wide range of environmental sources of stress, such as organic pollution, sedimentation, and fluctuating water levels. This advantage presumably arose from numerous morphological and physiological specializations which are expressed through appropriate behavioral patterns. Of prime importance is the ritualistic redd building and guarding behavior developed by the pikeperch which contributes to a consistently successful rate of fertilization and lowered mortality of their eggs and larvae. In addition, pikeperch have a much higher fecundity and require a less specific set of spawning conditions than do walleye. These attributes allow the pikeperch much greater reproductive success under stressful conditions and thus more flexibility in their range.Key words: behavior, cultural eutrophication, environmental stress, morphology, physiology, pikeperch, reproductive potential, reservoirs,Stizostedion, walleye

ISSN:0706-652X    

DOI:10.1139/f77-216

出版商:NRC Research Press    

年代:1977

数据来源: NRC