bluuebunny/crossref_metadata_2025 huggingface dataset:
Rates of Accumulation of Phosphorus Forms in Lake Erie Sediments
Authors: Williams J. D. H. , Murphy T. P. , Mayer T.
Published: April 2011

Six Lake Erie sediment cores from locations of widely different sedimentation rates show that rate of input and sedimentation of apatite phosphorus at a given locality has been approximately constant during the last few hundred years relative to total sedimentation rate at the same locality. Apatite is not a significant source of soluble phosphorus for Lake Erie. By contrast, rate of sedimentation of nonapatite inorganic phosphorus (NAIP) and organic phosphorus has steadily increased in accordance with increased loadings in recent years of the source material, namely phosphorus of anthropogenic origin. The rate of sedimentation of these two forms of phosphorus at a given locality varied greatly within the lake, and was greatest where the most fine-grained sediments were accumulating. It was concluded that the sediments of Lake Erie contain sufficient orthophosphate-retaining sites to prevent major regeneration of phosphate under any conceivable condition provided the overlying water remains oxic.
A Phosphorus Budget for Lake Erie
Authors: Burns N. M. , Williams J. D. H. , Jaquet J.-M. , Kemp A. L. W. , Lam D. C. L.
Published: April 2011

A budget for phosphorus retention in Lake Erie during 1970 has been drawn up. Phosphorus associated with sand-sized particles (> 63 μm) was excluded. Retention of apatite phosphorus (AP) and nonapatite phosphorus (NAP) within each of the three basins of the lake (Western, Central, and Eastern) was estimated in each case by two independent methods. The two estimates of retention of total phosphorus within the entire lake agreed to within 9.5% of their mean. The estimates of AP retention within the Western basin also agreed well. However, the input–output balance estimates of AP retention in the Central basin and of NAP retention in the Western and Central basins greatly exceeded the corresponding sedimentation values, while in the Eastern basin this pattern was reversed. The AP discrepancy was attributed to unobserved transport of AP from the Central to the Eastern basin via nearshore currents past Long Point, while the NAP discrepancies were largely attributed to eastward movement of NAP through the lake within about 2 m of the lake bottom. The total amount of phosphorus retained within the lake in 1970 was 41,000 metric tons, or about 92% of input. AP of natural origin and inert nature accounted for approximately 44% of the total phosphorus retained. A reduction in anthropogenic phosphorus input of about 15,000 metric tons/yr, as called for in the Great Lakes Water Quality Agreement, will reduce present annual NAP loading to close to pre-1850 values.
Relationships of Phytoplankton Biomass with Soluble Nutrients, Primary Production, and Chlorophyll a in Lake Erie, 1970
Authors: Munawar M. , Burns N. M.
Published: April 2011

Comparison of the annual average distribution patterns of phytoplankton biomass, chlorophyll a, primary production, soluble reactive phosphorus, nitrate + nitrite, and ammonia concentrations revealed that these six variables had very similar distributions in Lake Erie during 1970. However, statistical analysis of the data only revealed a few consistent relationships between these variables. The phytoplankton biomass was correlated with chlorophyll a only in the summer and fall as was primary production with chlorophyll a and biomass. There was no correlation between these three variables during the spring. Also, there was no consistent relationship between biomass and soluble nutrients. The primary production and activity coefficient (mg Cassimilated per milligram phytoplankton biomass per day) were found to be unrelated to temperature. The statistical procedure of factor analysis showed that in the spring, primary production correlated with the phosphorus and nitrogen soluble nutrients only, whereas during summer, primary production correlated with biomass, chlorophyll a, the major plankton groups (Cyanophyta, Chlorophyta, Chrysomonadinae, and Diatomeae), and the phosphorus nutrients. In the fall, production was positively correlated with phytoplankton biomass and with the Chlorophyta in particular. The use of chlorophyll a and temperature as variables in the equation to estimate phytoplankton growth in Lake Erie was found to be questionable.
The Fish Community in Lake Erie
Authors: Leach J. H. , Nepszy S. J.
Published: April 2011

Lake Erie, because of its shallowness and the fertility of its drainage basin, is the most productive of the Laurentian Great Lakes. The fish community is diverse (114 species representing 24 families) and is dominated by mesothermal and warmwater species. Although commercial fish production has been fairly consistent (average annual yield of 23,000 metric tons since 1915) there has been a dramatic change in species composition during the last 150 yr. Lake sturgeon, lake trout, lake herring, lake whitefish, sauger, and blue pike have virtually disappeared. Commercial production of medium-priced species such as yellow perch and white bass has increased and lower-valued species such as rainbow smelt, alewife, and freshwater drum have become more dominant in the fishery. The cultural stresses deemed largely responsible for these changes are, in approximate order of effect, an intensive commercial fishery, nutrient loading, the introduction of nonnative species, tributary and shoreline restructuring, erosion and siltation, and the introduction of toxic materials. The effects of these stresses on the environment and species composition are discussed.The current status and future of the remaining commercial species are considered in the light of past and present effects of the cultural stresses. The joint efforts of the United States and Canada to improve water quality and to control and reduce nutrient loading should lead to an improvement in the environment in the near future. Lake Erie is well suited for the production of valuable percid species but unless a strong effort is made to regulate exploitation the future of the commercial fishery is precarious.
Processes Within Lake Erie
Authors: Burns N. M. , Jaquet J.-M. , Kemp A. L. W. , Lam D. C. L. , Leach J. H. , Munawar M. , Simons T. J. , Sly P. G. , Thomas R. L. , Watson N. H. F. , Williams J. D. H.
Published: April 2011

The current level of knowledge concerning Lake Erie is inadequate for the development of a predictive model of the system. Nevertheless, an outline of the submodels required for the development of a predictive model is presented. Further, as a result of many recent studies, the level of understanding of the Lake Erie system has increased immensely and major gaps in the present knowledge of the lake have been identified; useful areas for future research have been indicated. Many of the recent studies on Lake Erie are included in this special issue. The results of these investigations have been summarized and linked together where possible, to describe the lake and give an overview of the more important processes in Lake Erie.
Aquaculture Revisited
Authors: Bardach John E.
Published: April 2011

Opportunities for and constraints of animal aquaculture are considered with special reference to the Pacific basin. Choice of species for husbandry depends on biological, cultural, and marketability criteria. Seed production (spawning and larval rearing) may be centralized, with certain economy of scale advantages, even in artisanal aquaculture enterprises, provided adequate distribution facilities for postlarvae are made. Larval survival rates for several actual or potential cultivars still need enhancement through applied research. Practices for the growout phase of aquatic stock differ, depending on the intensity of fixed and variable inputs, by analogy with terrestrial systems one may distinguish feedlot, managed pasturage, and ranching modes. For much of tropical Asia best expansion opportunities exist in managed pasturage polyculture possibly combining the grow-out of crustacea for export with local, largely herbivorous and planktivorous semistaple species. Extraneously supplied feeds, when used, will differ with the species and locally available raw materials. Nonbiotechnical constraints to aquaculture expansion are found in the areas of training, credit, extension, social impact of change, and information dissemination. They may be as difficult, if not more difficult, to overcome as purely biological ones.
Science for the Scattered Fisheries of the Canadian Interior
Authors: Regier Henry A.
Published: April 2011

A healthy ferment exists in various fields of scientific research and management on Canadian freshwater fisheries. Important achievements have been registered in ecology, as well as in economics and on legal–jurisdictional aspects. The time is right to bring some order into recent administrative chaos to consolidate scientific contributions of the past, to encourage some recent initiatives, and to expedite research that is explicitly interdisciplinary, i.e. organized from transdisciplinary perspectives and conducted so that the contributions of various disciplines are not readily discernible in the end products. A capability to transfer insights and information directly to planning and decision-making on large fisheries programs, on major industrial developments, and to regional governments and agencies is badly needed. Such a capability for freshwater fisheries can be stimulated into maturity by expanding and developing some five or six interdisciplinary and interinstitutional scientific networks that have evolved in various parts of Canada in recent decades. These and other specific conclusions are specified in some detail.
Production of Wild, Domestic, and Interstrain Hybrids of Brook Trout (Salvelinus fontinalis) in Natural Ponds
Authors: Flick William A. , Webster Dwight A.
Published: April 2011

Hatchery-reared wild and domestic strains of brook trout (Salvelinus fontinalis) were released in natural lakes, and survival and growth estimated at semiannual intervals throughout the life span. Angling was restricted. Four experiments with two year-classes involved three different Adirondack Mountain (New York) wild strains and two domestic strains, a fifth experiment included two wild strains from James Bay, Quebec and a hybrid between one of these (Assinica Lake) and a New York domestic strain. Wild and hybrid strains consistently exhibited greater longevity (5–7 yr) compared with domestic (few recovered after 3 yr). Climax sizes were not much different, except the Domestic × Assinica hybrid that was substantially larger than either of the two parents. Gross production and yield to angling of any given strain cohort was correlated (r = 0.93) and life-span gross production was 50% greater for wild and hybrid groups per unit fish stocked. Biomass stocked per recruit was much larger for domestic strains, and taking this into account, the ratio of gross production to weight stocked was about 6 times greater. Increased costs of rearing nondomesticated strains, if any, must be taken into consideration in an economic evaluation, but use of wild and/or hybrid strains of trout offers significant benefits under management conditions of these experiments.
Analyses of Gastric Emptying in Bluegill (Lepomis macrochirus)
Authors: El-Shamy F. M.
Published: April 2011

Bluegill (Lepomis macrochirus) fed a single meal averaging 111.6 mg dry wt (2.19% body wt on a wet fish and food basis) showed an average of 60 mg (54%) of the meal remaining after 8 h of digestion compared to 71 mg (59%) of an equivalent amount of food (119.6 mg or 2.04% body wt) fed in two consecutive meals. Fish fed a single meal averaging 167.2 mg (2.74% body wt) showed an average of 41% of the meal remaining 12 h after feeding, while fish fed three consecutive meals totaling 140.3 mg (2.51% body wt), showed an average of 47% of the food intake remaining 12 h after they were first fed. Two statistical models — an exponential and a multiple regression — relating food digested to meal size and time of feeding were developed. Both statistical models, when based on results of fish fed single meals, failed to predict values comparable to those observed for bluegill fed multiple meals.
Growth Per Molt and Limb Regeneration in the Spider Crab, Chionoecetes opilio
Authors: Miller R. J. , Watson J.
Published: April 2011

Spider crabs, Chionoecetes opilio, were held in the laboratory for observations on carapace width increments and limb regeneration per molt. The merus (the longest limb segment) of autotomized limbs regenerated to 48 and 73% of their full length, irrespective of crab size, on the first and second molt, respectively. Fitting least squares regressions to percentage increase of carapace width per molt (Y) vs. premolt carapace width (X [in millimeters]) gave the following equations: immature males Y = 40.7 − 0.363X; immature females Y = 45.3 − 0.444X; mature males Y = 14.2 + 0.051X; and females’ terminal molt to maturity Y = 14.0 − 0.014X. Only the slopes for the first two equations differed significantly from zero. Growth per molt decreased with sexual maturity for both sexes and was significantly less for females molting to maturity than for mature males of the same size. Growth per molt for immature females was significantly greater than for immature males, but the difference was slight.
Ecology of Euphausiids in the Gulf of St. Lawrence
Authors: Berkes F.
Published: April 2011

Geographical and vertical distributions, reproduction, growth and maturity, food and feeding of Meganyctiphanes norvegica, Thysanoessa raschii, T. inermis, and T. longicaudata in the Gulf of St. Lawrence were studied, based on plankton samples from 10 cruises, largely from 2 consecutive yr. Adults of the first three species occurred most abundantly in the western Gulf and their larvae in the Magdalen Shallows. By contrast, T. longicaudata, an oceanic species, occurred mainly in the eastern Gulf year-round. All four species reached reproductive maturity at 1 yr of age; all but T. longicaudata populations contained at least two breeding year-classes. The three Thysanoessa species started spawning in April at the time of the phytoplankton bloom; M. norvegica was a summer breeder. All four species were omnivorous, but M. norvegica and T. longicaudata stomachs contained relatively more animal matter than those of the other two. These findings were supported by studies on the morphology of feeding appendages.Thysanoessa longicaudata was differentiated from the other species mainly on the basis of distribution patterns, and M. norvegica from the remaining two mainly on the basis of differences in feeding and reproductive season. In contrast to relatively clear resource partitioning in five of the six species pairs, only relatively small differences in the stomach content composition in winter samples, the spacing of setules, and the length of the breeding season differentiated T. inermis from T. raschii.
Community and Species Responses of Chironomidae (Diptera) to Contamination of Fresh Waters by Crude Oil and Petroleum Products, with Special Reference to the Trail River, Northwest Territories
Authors: Rosenberg D. M. , Wiens A. P.
Published: April 2011

On oiled and unoiled artificial substrates in the Trail River, Northwest Territories, communities of Chironomidae were different during open-water periods but were similar over the winter. Greater numbers of species and individuals of Orthocladiinae occurred on the oiled than on the unoiled artificial substrates. The reverse was true for Tanypodinae and Chironominae. Ten species of Chironomidae showed a positive response to the presence of oil, 9 species showed a negative response, and 10 species were apparently unaffected. Based on the results of this study and a literature review, 11 species of Chironomidae showing either positive or negative responses to contamination by oil or petroleum products were evaluated for their potential to indicate oil contamination of freshwater ecosystems. Three criteria were used: taxonomic soundness, wide zoogeographic distribution, and numbers in the community. We predict that Nilotanypus fimbriatus (Walk.), Cricotopus bicinctus (Meig.), and C. varipes Coq., individually or as an assemblage, would fulfill this role.
Seasonal Growth Rates of Mooneye (Hiodon tergisus) from the Assiniboine River
Authors: Glenn C. L.
Published: April 2011

Length increments, calculated from fish measured at capture and from estimates of back-calculated lengths at time of formation of the most peripheral scale annulus, were used to determine the growing season and seasonal growth rates of mooneye (Hiodon tergisus). Data from 670 fish indicate that mooneye grow rapidly from June to mid-August with little or no growth occurring during other months. Length increased as a linear function during summer. Summer growth rates of 0.89, 0.58, 0.49, 0.44, 0.23, and 0.16 mm/day were estimated for fish aged I–VI, respectively.
A Study in the Slope Water Region South of Halifax
Authors: Gatien M. Germaine
Published: April 2011

Based on a reanalysis of the data from the Gulf Stream ’60 survey I propose that the Slope Water is comprised of two distinct zones. The first, warm Slope Water, is a well-mixed zone found between 0 and 400 m depth close to the Gulf Stream; the flow is primarily eastward. The second zone, Labrador Slope Water, is deeper, clings to the continental slope below 100 m and is broadest near σt = 27.5; it is poorly mixed and flows to the west. The boundary between the two zones varies in shape and intensity in response to changes in the Gulf Stream and the Labrador Current. Observations made in the Slope Water region south of Halifax in November 1973 are discussed in terms of the two Slope Water zones. In particular, movements of the boundary between the two zones are examined.
Numerical Modeling of Tides in Hudson Bay
Authors: Freeman N. G. , Murty T. S.
Published: April 2011

A two-dimensional numerical model is developed to study the cooscillating and independent tides in Hudson Bay. Using centered differences (forward differences for the dissipative term) and conjugate Richardson lattices, the Laplace Tidal Equations in spherical polar coordinates are integrated in time until cyclic equilibrium is reached. For the cooscillating tide, the direct tidal forcing term is set to zero, and the observed tidal constituent is specified at the mouth of Hudson Bay. Separate runs are made for M2, S2, N2, and K1. For the independent tide, the closed mouth boundary condition of zero water transport is imposed, and the model run for the M2 and K1 direct tidal forcing. A number of experiments are carried out to test the sensitivity of the model to uncertainties in the input data and parameterization of some of the terms. It is shown that the tidal propagation is relatively insensitive to friction coefficient and island schematization, but very sensitive to depth representation in the Belcher Islands area and phase variation in the specified boundary conditions.Comparison of the results with previous work and shore-based gauge observations gives good amplitude and phase agreement for the M2, S2, and N2 cooscillating tidal constituents except in the vicinity of the degenerate amphidromic points in James Bay and the Belcher Islands where the amplitudes are very small. The amplitudes of the K1 independent tide, unlike the M2, are found to be upwards of 30% of the K1 cooscillating tide. The M2 cooscillating tidal currents, when compared with current meter results at two stations across the mouth of James Bay, show good agreement in west–east decrease in amplitude, reversal of direction of rotation, and increase in rotary character, but generally tended to underestimate the absolute magnitude of these single depth measurements. Overall, the model gives good qualitative agreement with shore-based data and can be used to interpret tidal propagation in the Hudson–James Bay system.
Changes in Proximate Composition of the Crayfish Orconectes propinquus with Size, Sex, and Life Stage
Authors: Stein Roy A. , Murphy Michael L.
Published: April 2011

We estimated percent water, inorganic material, and chitin for the crayfish Orconectes propinquus. To properly account for organic materials and mineral salts, we burned samples first at 550 C then at 650 C for estimates of the inorganic fraction. More precise estimates were obtained at 650 C; thus, to account for the conversion of CaCO3 to CaO and CO2 at 650 C, inorganic estimates were multiplied by an empirically derived factor (1.5) to convert all values to total inorganic material. For chitin, acid decalcification, followed by deproteinization with base and combustion at 650 C, provided best estimates. Proximate composition varied with size, sex, and molt stage. Percent water was inversely related to size for juveniles but was constant with size in adult males (68.4%) and females (67.4%). Percent inorganic material and chitin of dry weight increased with size in juveniles; inorganic continued to increase with size following maturity while percent chitin remained constant. For a carapace length of 25 mm, adult males had significantly more inorganic material (46.2 vs. 38.1%) and chitin (16.3 vs. 14.1%) than adult females. Differences in proximate composition appeared related to secondary sexual characteristics, with males having longer, wider chelae but narrower abdomens than females. Recent molts had more water (84.1%) and less inorganic (19.0%) and chitin (9.1%) than either male or female intermolts. Understanding how these proximates vary with life stage is necessary for adequately describing transfer of energy and biomass between populations.
Early Stages of Some Copepods (Crustacea) Parasitic on Marine Fishes of British Columbia
Authors: Kabata Z.
Published: April 2011

Detailed descriptions and illustrations are presented of the nauplii (the only, or the first nauplius stage) of Bomolochus cuneatus, Holobomolochus spinulus, Chondracanthus gracilis, Ergasilus turgidus, Eudactylina similis, Pseudocharopinus dentatus, and Haemobaphes diceraus, and the copepodid stages of H. diceraus, P. dentatus, and Nectobrachia indivisa.The naupliar morphology of Ergasilus is similar to that of free-living Cyclopidae but differs in significant details from that of supposedly related Bomolochus. The nauplii of poecilostome and siphonostome copepods are similar. The morphology of the free-living larval stages might offer valuable clues to intrafamilial relationships of Lemaeopodidae. Differences were observed between copepodids of two species of Haemobaphes.
Physiological Response of Juvenile Coho Salmon (Oncorhynchus kisutch) and Rainbow Trout (Salmo gairdneri) to Handling and Crowding Stress in Intensive Fish Culture
Authors: Wedemeyer Gary A.
Published: April 2011

Moving 4–5-in. coho salmon (Oncorhynchus kisutch) held in soft (20 ppm CaCO3) water from the relatively light loading density of 0.5 lb/ft3 to 1, 2, or 4 lb/ft3 (density index, DI = 0.1, 0.2, 0.4, 0.8) caused significant stress as indicated by loss of feeding behavior, but only minimal physiological disturbances, as indicated by lack of hyperglycemia or hypochloremia. However, moving them to 6 or 12 lb/ft3 (DI = 1.2, 2.4) caused significant physiological stress which required at least a week for recovery. Smolting coho salmon were physiologically stressed by population densities of 1 lb/ft3 or more and a subclinical corynebacterial kidney infection was activated. Rainbow trout (Salmo gairdneri) (4–5 in.) were physiologically stressed when moved and held at 1 lb/ft3 or more but retained normal feeding behavior. This indicates that handling and crowding stress will be minimized in softwater areas if densities in fish distribution trucks or in ponds or raceways during disease treatments are held to 0.1–0.5 lb/gal.
Marine Phytoplankton Growth in High Concentrations of Pulpmill Effluent
Authors: Stockner John G. , Costella Anne C.
Published: April 2011

Axenic culture studies with the marine phytoplankton Skeletonema costatum, Dunaliella tertiolecta, and Amphidinium carteri demonstrated the ability of these species to adapt to and exhibit normal growth in relatively high concentrations of pulpmill effluent. Skeletonema costatum and A. carteri required a preadaptation period prior to commencement of exponential growth in high concentrations of kraft effluent (20–30%), while D. tertiolecta exhibited exponential growth in 90% kraft effluent with no requirement for preadaptation. Of six pulpmill effluent types tested, kraft was considered most inhibitory to growth, while combined kraft and newsprint effluent passed through an XAD-8 resin column was least inhibitory. The effects of the six effluent types on lag, exponential, and stationary growth phases are discussed in relation to in situ concentrations and relative ecological significance in the coastal marine environment.
Chemical and Sensory Changes in Round Inshore Male Capelin (Mallotus villosus) During Prolonged Storage for 24 Months at −23 °C
Authors: Shaw D. H. , Botta J. R.
Published: April 2011

Male capelin (Mallotus villosus) from a spawning inshore stock were held whole in block frozen format −23 °C without the benefit of special protective treatments. The results indicated an exceptional storage life of the samples, with no development of oxidative rancidity as monitored by organoleptic analysis, although TBA data did indicate this possibility. For many variables, the major chemical and sensory changes appeared to occur as a result of freezing and thawing, rather than as a result of frozen storage; changes were fastest during the first 6 wk. Because of the high sensory scores, it was difficult to correlate most chemical tests and organoleptic changes, though the relationship of texture scores to EPN and FFA values was significant [Formula: see text]. Sensory analyses showed that, after 2 yr, the samples were still fully acceptable.
Occurrence of Piscine Erythrocytic Necrosis (PEN) in the Blood of the Anadromous Alewife, Alosa pseudoharengus, from Maine Coastal Streams
Authors: Sherburne Stuart W.
Published: April 2011

Piscine erythrocytic necrosis (PEN) is reported in the blood of anadromous alewives, Alosa pseudoharengus, from Maine coastal streams in 1975. This is the first time PEN has been found in any pelagic anadromous fish.Of 991 alewives collected in 21 samples, 56.1% (371/661) of the prespawning and 10.5% (6/57) of the postspawning alewives had PEN. Within an individual the greatest number of infected red cells was 0.17% (1/600). PEN was not found in 273 juveniles sampled from streams where PEN had been evident in pre- and/or postspawners.The difference in infection rates between prespawners, postspawners, and juveniles may be due to either latent or acquired infections. Since alewife PEN resembles that of cod, it may be viral and the possibility exists that other species may be infected.These results indicate that management practices in which alewives are transferred from one stream to another for the development and maintenance of commercial runs contribute to the spread of PEN.
Comparison of an Ecological Model of Lake Ontario and Phosphorus Loading Models
Authors: Scavia Donald , Chapra Steven C.
Published: April 2011

Predicted responses of Lake Ontario to phosphorus loads from two empirical relationships and an ecological model were compared. Predictions of annual average concentrations of total phosphorus and chlorophyll a by the ecological model were consistent with those predicted by the simpler models. We concluded that the use of a particular type of model is governed by the nature of the problems being addressed rather than an inherent superiority of either approach.
Temperature and Photoperiod Regulation of Rheotropic Behavior in Prespawning Common Shiners, Notropis cornutus
Authors: Dodson Julian J. , Young J. Clifton
Published: April 2011

The upstream orientation and frequency of upstream movement of prespawning common shiners, Notropis cornutus, in response to a water current simulated by moving a striped background past the fish were observed at three temperatures (10, 15, 20 °C) and two photoperiods (12L: 12D and 16L: 8D). The greatest frequency of upstream movement was induced by a combination of spring day lengths and warm water temperatures. Further increases in the frequency of upstream movement followed immediate 5 °C increases in water temperature. Neither temperature nor photoperiod had a major effect on the frequency of upstream orientation. The significance of environmental regulation of rheotropism as a mechanism of upstream migration is discussed.
Isolation and Characterization of an Anaerobic Bacterium, Eubacterium tarantellus sp.nov., Associated with Striped Mullet (Mugil cephalus) Mortality in Biscayne Bay, Florida
Authors: Udey Lanny R. , Young Elaine , Sallman Bennett
Published: April 2011

An asporogenous, gram-positive, anaerobic bacterium was isolated in pure culture from the brains of numerous dead and moribund striped mullet (Mugil cephalus) from Biscayne Bay, Florida. Biochemical characterization confirmed that it was a new species and has been named Eubacterium tarantellus (ATCC 29255). All isolates produced lecithinase and deoxyribonuclease, were beta hemolytic, but only weakly fermented selected carbohydrates. This anaerobe was pathogenic for channel catfish (Ictalurus punctatus) but not for white mice or guinea pigs.More recently E. tarantellus has been isolated from 10 additional fish species. This and other anaerobic bacteria may be significant pathogens of estuarine fish. Key words: Anaerobic bacteria, Eubacterium, Mugil cephalus, and fish diseases.
Effects of Chemical Additives on Extending the Shelf Life of Frozen Minced Sucker (Catostomidae) Flesh
Authors: Iredale D. G. , York R. K.
Published: April 2011

A 44-day accelerated storage test at −4 °C was used to evaluate the relative effects of sodium erythorbate, disodium EDTA, and sodium tripolyphosphate on the development of oxidative rancidity in samples of minced sucker. Sensory testing and 2-thiobarbituric acid values were used to evaluate the changes in the samples. Sodium erythorbate was found to inhibit the development of oxidative rancidity as determined chemically and to contribute to maintaining a higher flavor score in the sensory testing.
Detection of Trace Contaminant Effects in Aquatic Ecosystems
Authors: Luoma Samuel N.
Published: April 2011

If one population of a species is more resistant to a toxicant than are other populations, it is direct evidence that the concentration of the toxicant in the environment of the resistant population is sufficient to elicit biological effects. The presence of a toxicant-resistant population of one species in an ecosystem further suggests that other species may have been affected by the resistance-eliciting substance.
Development of a Blood Sugar Bioassay for Rapidly Measuring Stressful Levels of Pulpmill Effluent to Salmonid Fish
Authors: McLeay Donald J.
Published: April 2011

The hyperglycemic stress response of fish was evaluated for use as a rapid test for assessing stressful levels of pulpmill effluents (BKME). Plasma glucose levels in juvenile coho salmon (Oncorhynchus kisutch) were elevated within 0.5 h following transfer from the holding tank to aquaria containing either fresh water or BKME, peaking at 3–6 h and returning to near-basal levels at 24 h. Acclimation of coho to aquaria for 24, 48, 72, or 96 h prior to addition of effluent resulted in marked increases in glucose levels attributable to BKME. Significant responses to effluent were found with exposures of 3–10 h, whereas levels were not increased with exposures of 2 h or less. Plasma glucose levels increased progressively with increasing effluent concentrations. Threshold effect (EC50) values varied from 0.04 to 0.16 of the 96-h LC50 values. The response to BKME treated previously by the activated sludge process or by foam separation was diminished or absent altogether.Juvenile rainbow trout (Salmo gairdneri) and coho displayed a hyperglycemic response with 4-, 6-, or 8-h exposure to an identical effluent concentration, although the magnitude of response of rainbow was less in each instance.The extent to which blood sugar levels are elevated due to effluent exposure is directly related to the liver glycogen reserves of the fish. Acclimation to test tanks for 24–48 h followed by exposure for 3–6 h is suggested as the best working combination for this test.
Effects of Thermal Shocks on Drifting Aquatic Insects: A Laboratory Simulation
Authors: Sherberger Fred F. , Benfield Ernest F. , Dickson Kenneth L. , Cairns Jr. John
Published: April 2011

Effects of temperature shocks from thermal plumes on drifting Isonychia (Ephemeroptera: Baetidae) and Hydropsyche (Trichoptera: Hydropsychidae) larvae were examined in a laboratory simulation. Groups of both insects were collected at various seasons and acclimated in the laboratory at temperatures comparable to those in the field. Groups were exposed to thermal shocks of varying duration and observed for periods of 10 days afterward. Consistent statistically significant differences in mortality between treatment and control groups were not evident until shock temperatures neared the respective upper lethal limits for the two insects. While consistent treatment related differences in molting frequency in Isonychia were not obtained, changes in the patterns of molting were observed. Behavioral tests with Isonychia indicated no discernable treatment effects on rheotaxis, phototaxis, and substrate orientation. No discernable effects of treatment on susceptibility to predation of Isonychia by Cottus carolinae were observed.
Avoidance of Bleached Kraft Pulpmill Effluent by Pinfish (Lagodon rhomboides) and Gulf Killifish (Fundulus grandis)
Authors: Lewis III Frank G. , Livingston Robert J.
Published: April 2011

Avoidance of bleached kraft pulpmill effluent (BKME) by fish was investigated in a steep gradient trough. No significant difference was found between the responses of the two species. No avoidance was recorded at 0.01% BKME, while both species displayed a significant yet low avoidance at 0.1% BKME. A marked avoidance was observed for both species at 1.0% and 10.0% BKME. In both species the threshold avoidance level was estimated to be 0.06% BKME. Key words: avoidance responses, pulpmill effluent, estuarine fishes
Efficiency of Nets and a New Device for Sampling Living Fish Larvae
Authors: McGroddy P. M. , Wyman R. L.
Published: April 2011

Mortality of fish larvae when collected with a plankton net was shown to increase with the velocity of water moving through the net. In addition, the net retained fewer larvae at higher velocities. A device was designed and tested which efficiently concentrated living fish larvae at low velocities and reduces collection mortality. Key words: fish larvae mortality, plankton nets, new sampler.
Persistence of Dissolved Organic Compounds in Kraft Pulp and Paper Mill Effluent Plumes
Authors: Fox Michael E.
Published: April 2011

The persistence of dissolved organic compounds in the effluent plumes of a pulp and paper mill on the north shore of Lake Superior was studied in 1974. Approximately 90 organic compounds were observed of which 36 (including all the major ones) were identified.The dispersion of five of these compounds was examined quantitatively. Dehydroabietic acid was the only major organic compound observed to exhibit measurable persistence >2000 m from the effluent discharge. At 2000 m from the discharge, levels of ~30 μg/ℓ dehydroabietic acid were detected within the plume and ~15 μg/ℓ outside the effluent plume. The disappearance of dehydroabietic acid parallels that of the conservative ion Na+, indicating dilution by the receiving water as the only significant short-term removal mechanism.
Relation between Nipigon Bay Benthic Macroinvertebrates and Selected Aspects of Their Habitat
Authors: Wal J. Vander
Published: April 2011

In areas of Nipigon Bay unaffected by pulp and paper mill effluent, the benthic macroinvertebrate community was characterized by low standing stocks and high diversity. The coefficient of community and percentage similarity of community defined two major environments in Nipigon Bay, generally related to distance from the mill outfall. Near the pulp and paper mill outfall, further zonation of the benthic macroinvertebrate community was apparent. Inhibition and ultimate extinction of oligochaete populations appeared related to increasing levels of organic carbon and total sulphur, both associated with proximity to the outfall. Since a 10-yr period following abatement measures has not resulted in major responses by the macroinvertebrate community, recovery is expected to be slow.
Extent of Effluent Influence on Lake Water Determined by Bacterial Population Distributions
Authors: Rokosh D. A. , Rao S. S. , Jurkovic A. A.
Published: April 2011

Populations of heterotrophic bacteria, total and fecal coliforms, and sulfur cycle bacteria were measured in a large body of water receiving the effluent of a pulp and paper industry. Elevated bacterial populations were detected near the effluent outfall but persistent populations, larger than those in unaffected lake water, extended as far as 19 km from the effluent outfall. This ability to detect influences to distances up to 19 km adds a new dimension to a description of a mixing zone receiving industrial effluents.
Assessment of the Acute Toxicity, Growth Impairment, and Flesh Tainting Potential of a Bleached Kraft Mill Effluent on Rainbow Trout (Salmo gairdneri)
Authors: Whittle D. M. , Flood K. W.
Published: April 2011

Static and continuous-flow bioassays utilizing juvenile rainbow trout (Salmo gairdneri) were conducted on a northern Ontario bleached kraft mill effluent to assess the range of acute toxicity and related sublethal effects. The acute toxicity of the total mill effluent, as determined by static bioassay procedures, ranged from a 96-h LC50 value of 14–49.0% vol/vol. The results of these bioassays depended on testing methodology and effluent treatment systems employed by the mill when samples were collected. Continuous-flow bioassays conducted on the effluent Produced 96-h LC50 values of 21.8 and 24.8% vol/vol. Growth rate of juvenile rainbow trout (1–2 g) held under continuous-flow conditions for 18 days was significantly reduced at 6% vol/vol effluent concentration (P < 0.05). Flavor of yearling rainbow trout [Formula: see text] exposed to 3% effluent for 48 h was significantly impaired (P < 0.05). This effluent concentration, the lowest level impairing flavor represents approximately 0.12 of the 96-h LC50 derived from continuous-flow bioassays. No significant flavor impairment was detected in fish exposed for 144 h to a 2% effluent concentration Flavor impairment at a 3% vol/vol effluent concentration, the most sensitive sublethal response measured in this study, may also be the most critical response when assessing the economic impact of a kraft mill discharge to a freshwater ecosystem.
Density, Distribution, and Movement of Nipigon Bay Fishes in Relation to a Pulp and Paper Mill Effluent
Authors: Kelso J. R. M.
Published: April 2011

Density of pelagic fish in accessible portions of Nipigon Bay was lower offshore, less than 100 fish/10,000 m3, and greater nearshore, less than 1800 fish/10,000 m3. Conditions at Red Rock caused intense aggregation there and caused species dominance to shift to sucker at the mill discharge from yellow perch elsewhere. Plume shape and direction did not alter the localized pattern of distribution. Two typical responses to plume concentrations were found using suckers fitted with ultrasonic transmitters. Fish released in high discharge concentrations (>15% dilution by volume) became disoriented for as much as several hours, then appeared to search for "background" conditions. Fish released in low discharge concentrations (<15%) immediately initiated an avoidance reaction. Although individuals tended to avoid areas of altered water quality, the community aggregated at Red Rock in response to, perhaps, increased production of benthic macroinvertebrates. However, telemetry indicated that residence time was short in the area of altered water quality.
Piscine Erythrocytic Necrosis Virus in Atlantic Cod, Gadus morhua, and Other Fish: Ultrastructure and Distribution
Authors: Walker Roland , Sherburne Stuart W.
Published: April 2011

Electron microscopy of erythrocytes of Atlantic cod, Gadus morhua, with piscine erythrocytic necrosis (PEN) shows a small cytoplasmic viroplasm (~ 1 μm), often with an adjacent coherent group of large (330 nm) icosahedral virions. The viroplasm is Feulgen-positive, so the agent is an erythrocyte icosahedral cytoplasmic deoxyribovirus (EICDV) analogous to others reported in red cells of poikilotherms. PEN lesions in cod blood cells were found in 11–16% of samples from New Brunswick, Maine, and Georges Bank. PEN was found in cod of 15–80 cm total length taken at depths of 5–90 m. Incidence in the Georges Bank area was higher at depths of about 55 m. Intensity of infection varied from < 0.01 to ~ 99% of mature red cells, without obvious relation to cod size, sex, or condition, or to depth at which taken. PEN infections are reported in various other fish species and in other areas. Key words: viral infections, cytology, ultrastructure, morphology, pathology, Atlantic coast fishes
Encyclopaedic Dictionary of Mathematics for Engineers and Applied Scientists.
Authors: Farmer D.
Published: April 2011

not available
Introduction to the Proceedings of the 1976 Percid International Symposium (PERCIS)
Authors: Colby Peter J.
Published: April 2011

not available
Biomass, Production, and Yields of Walleye (Stizostedion vitreum vitreum) and Yellow Perch (Perca flavescens) in North American Lakes
Authors: Carlander Kenneth D.
Published: April 2011

Compilation of available data indicated that walleye (Stizostedion vitreum vitreum) biomass in lakes averaged 16 kg/ha, but the data were not adequate to show relationships with mean depth, alkalinity, latitude, or morphoedaphic indexes of the lakes. Yellow perch (Perca flavescens) biomass also failed to show relationships with these factors. In small lakes and ponds with only perch, biomass ranged from 39 to 215 kg/ha, but in lakes with other species, perch biomass was under 65 kg/ha. Annual production of walleye was from 1.2 to 4.1 kg∙ha−1∙yr−1 and that of yellow perch was 21.9 kg∙ha−1∙yr−1. Average commercial yields of walleye ranged up to 3.06 kg∙ha−1∙yr−1, and sport fish yields averaged 3.7 kg∙ha−1∙yr−1. Annual commercial and sport yields decreased with latitude. Area of lake was negatively correlated with sport yield, but positively with commercial yield. The latter situation is believed to be an artifact of the sample and not a general trend. Commercial yield increased with total dissolved solids of the lakes. Lack of other correlations may be related to the fact that walleye biomass and yield do not bear a constant relationship to total biomass and yield. Key words: Percidae, Stizostedion, Perca, biomass, production, yield
Trends in Percid Yields from Lake of the Woods, 1888–1973
Authors: Schupp D. H. , Macins V.
Published: April 2011

Commercial yields of walleye (Stizostedion vitreum vitreum) increased from 1888 to the mid-1930s and then gradually declined to 1973. Commercial yields of sauger (S. canadense) and yellow perch (Perca flavescens), first recorded in 1926, were more stable than walleye yields. The increase in walleye yields was associated with declines in the yield of lake sturgeon (Acipenser fulvescens) and lake whitefish (Coregonus clupeaformis). Walleye yields declined from 1.7 kg∙ha−1 annually in the 1930s to 0.8 kg∙ha−1 during 1964–73. Exploitation by commercial and sport fisheries appeared to be the main cause of the decline. Creel surveys from 1967 to 1971 indicated that the sportfishing yield exceeded the commercial yield, and the combined harvest was near the high levels in the 1930s. Wider fluctuations in yield observed since the 1950s suggested that recruitment had become more variable. Short-term increases in growth rate were observed in one area after intensive walleye harvests, but in other parts of the lake no change in growth rates was observed. Sauger appeared to be increasing in abundance in the northern areas of the lake, probably in response to increasing turbidity. Key words: Percidae, yield trends, Stizostedion, Perca, harvest
Depreciation of the Warmwater Fish Community in the Bay of Quinte, Lake Ontario
Authors: Hurley D. A. , Christie W. J.
Published: April 2011

The sequence of fish species shifts since the 1930s in the Bay of Quinte is interpreted in terms of climatic changes and the influences of man. Among the latter, eutrophication is judged most important. The marked decrease in large piscivores in both eastern Lake Ontario and the Bay of Quinte as a consequence of these changes resulted in instability, exemplified by the explosions in populations of alewife (Alosa pseudoharengus) and white perch (Morone americana). Nutrients are imported to the bay, from Lake Ontario by way of alewife. This source has increased in the 1970s with the further decline of piscivores, and it brought about a greater fish production in the bay. We conclude that the Bay of Quinte and Lake Ontario interact significantly and should be studied as a single system.Because of its specialized feeding habits, the post-World War II rise of the walleye (Stizostedion vitreum vitreum) was related to events outside the Bay of Quinte, but its later decline was attributable to direct and indirect effects of eutrophication. Yellow perch (Perca flavescens), by contrast, were apparently not affected adversely by severe habitat changes induced by cultural eutrophication. Key words: Percidae, community ecology, species shifts, eutrophication, habitat changes
Percid Habitat: The River Analogy
Authors: Kitchell James F. , Johnson Murray G. , Minns C. Kenneth , Loftus Kenneth H. , Greig Lorne , Olver Charles H.
Published: April 2011

We propose that the optimum habitat of the percid fishes Perca flavescens, P. fluviatilis, Stizostedton vitreum vitreum, and S. lucioperca in lakes may be defined by the littoral and sublittoral environmental conditions equivalent to those in large, temperate rivers. Analogous habitat conditions include sand or gravel substrate, low current velocity, reduced light penetration (Stizostedion spp. only), temperatures optimal for growth and reproduction, and well-oxygenated spawning substrates. The species' evolutionary origins and reproductive patterns also reflect their riverine ancestral habitat. Evidence in support of the hypothesis is derived from the diversity of papers contributed to the PERCIS Symposium. Key words: Percidae, habitat, theory, Perca, Stizostedion
Responses of Percid Fishes and Their Habitats to Eutrophication
Authors: Leach J. H. , Johnson M. G. , Kelso J. R. M. , Hartmann J. , Nümann W. , Entz B.
Published: April 2011

Percid fishes are found in lakes that cover a wide range of trophic conditions. The responses of percids and their habitats to progressive cultural eutrophication are predictable. Alterations in physicochemical characteristics of habitats precipitate changes in phytoplankton, macrophytes, zooplankton, and benthos that are ultimately deleterious. Enrichment can lead to favorable responses in percids, but somewhere in the continuum of trophic conditions the responses become unfavorable. The relative level at which the response becomes negative varies with the species according to tolerances to altered environment, adaptabilities to new habitat and forage base, and reproductive behavior. Progressive eutrophication acts as a selective mechanism that leads to a predictable sequence of fish species. Other perturbations, such as exploitation and habitat modification, can act synergistically with cultural eutrophication in accelerating the sequence. As eutrophication proceeds, the succession of species may not lead to increased fish yield because part of the nutrient load may be channeled through unharvestable food chains. Key words: Percidae, habitat, eutrophication, species dominance, food habits, parasitism, disease