Showing papers in "Canadian Journal of Fisheries and Aquatic Sciences in 1980"
TL;DR: It is hypothesized that producer and consumer communities characteristic of a given river reach become established in harmony with the dynamic physical conditions of the channel.
Abstract: From headwaters to mouth, the physical variables within a river system present a continuous gradient of physical conditions. This gradient should elicit a series of responses within the constituent...
9,145 citations
TL;DR: Total ammonia-nitrogen (NH4-N) in artificial seawater was determined spectrophotometrically by a method in which indophenol blue is produced by the reaction of ammonia with salicylate and hypochlor...
Abstract: Total ammonia-nitrogen (NH4-N) in artificial seawater was determined spectrophotometrically by a method in which indophenol blue is produced by the reaction of ammonia with salicylate and hypochlor...
672 citations
TL;DR: Control measures did not become effective until after 1958, when a selective toxicant — the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) — was used to destroy larval lampreys in streams.
Abstract: Sea lamprey (Petromyzon marinus) entered the upper three Great Lakes in the late 1930s and began making sharp inroads into the fish stocks by the mid-1940s in lakes Huron and Michigan and the mid-1
472 citations
TL;DR: Overall results show P deficiency is generally greater than N deficiency in all the small lakes studied, embracing a wide range of maximum chlorophyll concentrations and N/P loading ratios.
Abstract: Physiological indicators of N and P deficiency were measured in summer populations of several central Canadian lakes. Measurements included six composition ratios (P/C, N/C, N/P, ATP/C, chlorophyll...
401 citations
TL;DR: In this paper, an age-structured model with knife-edge recruitment describes the dynamics of exploited, seasonally breeding populations, and an equation is derived that characterizes the economic optimal state of exploitation of a modeled stock.
Abstract: An age-structured model with knife-edge recruitment describes the dynamics of exploited, seasonally breeding populations. For management strategy, an equation is derived that characterizes the economic optimal state of exploitation of a modeled stock. A further generalization is derived to account for those species where recruitment to the mature stock occurs over many age-categories. Since the parameters all have phenomenological definitions, they can be estimated from information independent of the model. These parameters can also be estimated by regression of the model to catch and effort data. Test regressions of the general model are made on catch and effort data from three exploited fish stocks: the yellowtail flounder of New England, the Pacific halibut of Area II, and the haddock of Georges Bank; the corresponding R2 values are 0.75, 0.87, and 0.86. Although the confidence intervals for individual parameter estimates are very large, the estimates compare favorably with published parameter values. ...
311 citations
TL;DR: Ammocoetes are relatively sedentary burrowing animals and movement is related to water discharge, temperature, and season, and occurs predominantly downstream and at night.
Abstract: Ammocoetes are relatively sedentary burrowing animals. Movement is related to water discharge, temperature, and season, and occurs predominantly downstream and at night. Growth is asymptotic and seasonal. At the end of larval life, the ammocoete ceases to increase markedly in length and starts to accumulate lipid. Length–frequency curves and data on kidney growth indicate that, in relatively stable and productive sites, ammocoetes of long established populations of the landlocked and anadromous sea lamprey take ~ 5 yr to reach metamorphosing length. Many animals probably enter transformation within a further 3 yr. information from an isolated population in the Big Garlic River and from other tributaries of lakes Superior and Michigan, some of which had been treated with larvicide, shows that the onset of metamorphosis can be highly variable and is apparently related to the growth rates and size of larvae. A short larval life is usually associated with a fast growth rate of ammocoetes, as is sometimes found in rivers where the use of larvicide has reduced population density. The landlocked sea lamprey tends to metamorphose at a longer length and at a greater age than other parasitic lampreys. During metamorphosis, which usually begins in the summer, lampreys maintain length but lose weight as a result of mobilization of lipid. The time between initiation of transformation and onset of feeding is generally 4–10 mo. The downstream migration of metamorphosed animals is nocturnal and is influenced by freshwater discharge. Comparisons are drawn between the sex ratios of sea lampreys in the upper Great Lakes and those of other populations.Key words: ammocoete, habitats, growth, mortality, larvicide, lipid, metamorphosis, migration, sex ratio, Great Lakes.
298 citations
TL;DR: There are problems with present understanding of temporal and spatial scales of variability in both marine and freshwater planktonic environments and the algal responses to those scales and the use of inappropriate assumptions concerning the occurrence of steady-state conditions are asserted.
Abstract: This article is essentially a review of the temporal and spatial scales of variability in both marine and freshwater planktonic environments and the algal responses to those scales. I assert that t...
290 citations
TL;DR: Data from two streams suggest that macroinvertebrate community structure exhibits a predictable, graded response to heavy-metal pollution, and chironomids were virtually eliminated from rock-rubble, riffle habitats.
Abstract: Data from two streams suggest that macroinvertebrate community structure exhibits a predictable, graded response to heavy-metal pollution. In the more heavily stressed sections of both streams, mac...
278 citations
TL;DR: The size of 50% maturity in the eastern Bering Sea was estimated to be 102.8 and 101.9 mm (carapace length) for male and female Paralithodes camtschatica and 114.7 mm for male Chionoecetes bairdi.
Abstract: A new computer technique for estimating the size of 50% sexual maturity from crab morphometric data is described. Using nonhierarchical cluster analysis, crabs are assigned to either of two maturit...
268 citations
TL;DR: Fingerling rainbow trout, acclimated to hatchery raceways or laboratory aquaria, had low plasma cortisol levels, but during a stocking operation, there was a rapid rise in plasma cortisol concentrations during the initial capture, and high levels of plasma cortisol were maintained to the median tolerance limit.
Abstract: Fingerling rainbow trout, acclimated to hatchery raceways or laboratory aquaria, had low plasma cortisol levels (≤ 2 ng/mL), with no apparent daily cycle in levels. Netting of cohorts out of an aqu...
268 citations
TL;DR: The impact of logging with and without buffer strip protection on stream macroinvertebrates was examined through comparisons of community structure in commercially logged and control watersheds throughout northern California as mentioned in this paper.
Abstract: The impact of logging with and without buffer strip protection on stream macroinvertebrates was examined through comparisons of community structure in commercially logged and control watersheds throughout northern California. A nonparametric test of community dissimilarities within matched blocks of two control and one or two treated stations showed significant (P < 0.05) logging effects on unprotected streams when Euclidean distance and mutual information were used as dissimilarity indices, but not when chord distance was used. Shannon diversity in unprotected streams was lower (P < 0.01) than in control (unlogged) streams; densities of total macroinvertebrate fauna and of Chironomidae, Baetis, and Nemoura were higher in unprotected streams than in controls (P < 0.05). Streams with narrow buffer strips (< 30 m) showed significant effects by the Euclidean distance test, but diversity varied widely and was not significantly different from that in either unprotected or control streams. Macroinvertebrate com...
TL;DR: A new approach to length–frequency analysis which takes account of biological structure in the mean lengths and standard deviations in length for various age-classes of fish is presented.
Abstract: This paper presents a new approach to length–frequency analysis which takes account of biological structure in the mean lengths and standard deviations in length for various age-classes of fish. Th...
TL;DR: In this article, the growth in length of a group of animals is examined and each animal is assumed to grow according to the von Bertalanffy model with fixed parameters, but these parameters are allowed to differ depending on the species.
Abstract: The growth in length of a group of animals is examined. Each animal is assumed to grow according to the von Bertalanffy model with fixed parameters, but these parameters are allowed to differ betwe...
TL;DR: In this article, the multiplicative model described by Robson can be used to obtain estimates of annual standardized catch rate and its variance by including years in the model, and the corresponding estimate of standa...
Abstract: The multiplicative model described by Robson can be used to obtain estimates of annual standardized catch rate and its variance by including years in the model. The corresponding estimate of standa...
TL;DR: In this article, a new extraction procedure eliminates the need for grinding glass fiber filters by heating the filter in DMSO for 10min at 65 °C and subsequently filtering or centrifuging the sample after dilution with 90% acetone (6 mL).
Abstract: This new extraction procedure eliminates the need for grinding glass fiber filters by heating the filter in DMSO (4 mL) for 10 min at 65 °C and subsequently filtering or centrifuging the sample after dilution with 90% acetone (6 mL). Scenedesmus and Selenastrum species gave about 20% higher concentrations of chlorophyll a using this method as compared to the standard 90% acetone procedure or grinding in DMSO only. The difference between heated DMSO and 90% acetone was reduced when natural phytoplankton were analyzed.Key words: chlorophyll, Chlorophyta, dimethyl sulfoxide, acetone, extraction
TL;DR: The sea lamprey (Petromyzon marinus) in the western Atlantic Ocean adjacent to North America is usually found within a depth of 200 m between latitudes of 30 and 53° and energy requirements for migration and reproduction are discussed in the context of parental investment.
Abstract: The sea lamprey (Petromyzon marinus) in the western Atlantic Ocean adjacent to North America is usually found within a depth of 200 m between latitudes of 30 and 53°. Spawning size lampreys have been recorded in 116 rivers between 32 and 48° latitude. The upstream spawning migration which may extend to several hundred kilometres, takes place between March and September, the actual time varying directly with latitude. Fecundity of the anadromous P. marinus (approximately 124 000–305 000) is the highest for any lamprey species. Energy requirements for migration and reproduction are discussed in the context of parental investment. The larval phase lasts 6–8 yr and is followed by a highly synchronous period of metamorphosis. On completion of metamorphosis in late autumn some juveniles migrate downstream to the estuary or ocean and commence feeding. In at least some rivers, a portion of the young juveniles overwinter in the natal stream without feeding. Subsequent to a short feeding period in May these young j...
TL;DR: Sulfuric acid was used to add 1.60 eq∙m−2 of hydrogen ion ([H+]) to Lake 223 over a 3-yr period from 1976 to 1978, to simulate the effects of acid precipitation on chemical and biological characteristics of the lake.
Abstract: Sulfuric acid was used to add 1.60 eq∙m−2 of hydrogen ion ([H+]) to Lake 223 over a 3-yr period from 1976 to 1978, to simulate the effects of acid precipitation on chemical and biological character...
TL;DR: In this article, large diameter enclosures were sealed to the sediments in 2.5m of water in Lake 223 and two tubes were held at control pH (6.7-6.8), one was lowered to pH 5.7 and one to pH5.1, using H2SO4.
Abstract: Large (10 m) diameter enclosures were sealed to the sediments in 2–2.5 m of water in Lake 223. Two tubes were held at control pH (6.7–6.8), one was lowered to pH 5.7 and one to pH 5.1, using H2SO4....
TL;DR: Water from backwater and main-stem regions of three reservoirs and a natural lake belonging to major river systems in northern Manitoba showed that primary productivity was inversely related to total "dissolved" organic carbon and non-dialyzable dissolved iron, organic carbon, nitrogen, and H-bonded polymeric hydroxyl groups.
Abstract: Analysis of water from backwater and main-stem regions of three reservoirs and a natural lake belonging to major river systems in northern Manitoba (Canada) showed that primary productivity was inversely related to total "dissolved" (<0.45 μm) organic carbon and non-dialyzable dissolved iron, organic carbon, nitrogen, and H-bonded polymeric hydroxyl groups. The chemical data apparently represent allochthonous humic–FeOOH complexes with strong, covalent metal-ligand bonds. The results suggest that humic matter depressed primary productivity by making iron unavailable to phytoplankton, but not by attenuating light, lowering the pH, or sequestering phosphate (although the dissolved phosphorus appeared to be mostly in the form of humic-iron-phosphate complexes). Relatively stagnant backwater bays, where humic mater accumulates, were less productive than the more rapidly flushed, less humic main-stem waters. In addition, the reservoirs, which had been formed 6 mo, 3 yr, and 14 yr prior to the time of sampling,...
TL;DR: An examination of stomach contents indicated that vertical migrations were mechanistically linked to feeding behavior, and total lengths of Mysis in alewife stomachs were significantly longer than total lengthsof Mysis captured in vertical plankton tows.
Abstract: Vertical distributions of adult alewife (135–216 mm long) and Mysis relicta were measured acoustically on a 24 h basis during July, September, and October 1975 and June 1976 at a station 8 km north...
TL;DR: In this paper, a model of the commercial fishery, incorporating the microeconomic decisions of individual vessel operation, is developed and employed to predict the consequences of various methods of regulation.
Abstract: A model of the commercial fishery, incorporating the microeconomic decisions of individual vessel operation, is developed and employed to predict the consequences of various methods of regulation,
TL;DR: No stock should be founded or perpetuated using less than approximately 30 parents of the least numerous sex in any generation, and the importance of using large numbers of actual as well as effective parents to avoid inadvertent genetic changes and inbreeding is emphasized.
Abstract: Preservation of the genetic characteristics of a population is one of the primary objectives of many fish stocking programs. Using starch gel electrophoresis we have tested for temporal gene freque...
TL;DR: BIONESS (Bedford Institute of Oceanography Net and Environmental Sampling System) as discussed by the authors uses a new design concept with the nets arranged horizontally rather than vertically as in earlier multiple-net samplers.
Abstract: BIONESS (Bedford Institute of Oceanography Net and Environmental Sampling System), a new multiple-net zooplankton and micronekton sampler, uses a new design concept with the nets arranged horizontally rather than vertically as in earlier multiple-net samplers. Ten 1.0-m2 nets open sequentially and are towed at 3 knots on a conductor cable that transmits and receives information between the ship and sampler. On the sampler are sensors for temperature, conductivity, depth, illumination, pitch, roll and yaw, and net closure together with internal and external flowmeters and a 35-mm camera equipped with a strobe light. This system can collect biological samples and environmental data simultaneously and photograph animals in front of the sampler.Key words: samplers, zooplankton, micronekton, instrumentation, photography, data collection, design
TL;DR: Observations on P. marinus and other lamprey species shows that variations in the time of completion of transformation or development of organs reflect the immediate needs of the animal.
Abstract: Metamorphosis is highly synchronized in both landlocked and anadromous sea lampreys, Petromyzon marinus, and can be divided into seven clearly defined stages. Although there may be some subtle internal changes several months before the beginning of external metamorphosis, most internal and external changes are initiated simultaneously in early July in P. marinus. The time and degree to which various external anatomical features take place does not differ to any large degree in landlocked and anadromous sea lampreys. Observations on P. marinus and other lamprey species shows that variations in the time of completion of transformation or development of organs reflect the immediate needs of the animal. For example, transformation of the liver and development of the kidneys occur very early (stage 4) whereas organs and tissues involved in osmoregulation, feeding, and digestion do not reach their definitive adult condition until later stages. All organ systems seem to undergo some morphological transformation ...
TL;DR: The significant changes in the polychaete community beneath a variety of cages installed on a highly wave-exposed sand bottom could not be explained by the presence or absence of predatory demersal fishes.
Abstract: Caging manipulations were performed in two marine soft-bottom communities to test two nonexclusive hypotheses: (1) polychaete abundance changes in cages are caused by the presence or absence of particular predators and competitors; (2) polychaete changes in cages are caused by animals responding to cage-induced habitat modifications, especially sediment deposition and erosion.The significant changes in the polychaete community beneath a variety of cages installed on a highly wave-exposed sand bottom could not be explained by the presence or absence of predatory demersal fishes. This result was obtained despite the exclusion of fish which normally consume large numbers of infaunal polychaetes.A caging experiment similar to Woodin's (1974) was performed in the channel of Elkhorn Slough using comparable cages and similar exposure period. In Woodin's experiments, the exclusion of a sedentary tube builder was accompanied by an increase in a mobile deposit feeder. This was interpreted as a competitive release. ...
TL;DR: Pacific lamprey (Lampetra tridentata) begin metamorphosis in July and the known period of entry into salt water is from December until June and feeding can commence in freshwater or salt water by mid-October.
Abstract: River lamprey (Lampetra ayresi) metamorphose in late July with downstream migration occurring in the following year from May to July. Once adults enter salt water they begin to feed immediately by ...
TL;DR: The results indicate that significant deleterious effects occur when larvae are reared at the two lowest prey densities, and growth depensation leading to size hierarchies was not correlated with prey density.
Abstract: Growth and survival rates were determined for 4- to 12-wk-old herring larvae (Clupea harengus) reared at prey densities of 0.03, 0.1, 0.3, 1.0, and 3.0 Artemia nauplii/mL. The time required for foo...
TL;DR: This study shows that hypolIMnion oxygen represents hypolimnion thickness and temperature as well as productivity, and a relationship based on the multiplicative effects of chlorophyll, thickness, and temperature closely fits the observed oxygen depletion in the Laurentian Great Lakes.
Abstract: Until recently, hypolimnion oxygen consumption was thought to be a way of comparing the productivity of lakes. This study shows that hypolimnion oxygen represents hypolimnion thickness and temperat...
TL;DR: Increased corticosteroids were correlated to increased mortality in transported salmon compared to acclimated control fish when subjected to a bioassay of stress — severe confinement.
Abstract: Smolting coho salmon (Oncorhynchus kisutch) were transported experimentally at low and high densities (12 and 120 g/L) for short and long periods (4 and 12 h). Because smolts can be transplanted di...
TL;DR: Significant differences have been found between the larvae of nonparasitic lampreys and those of their parasitic ancestor in such features as the number of oocytes, trunk myomeres, and size at the onset of metamorphosis.
Abstract: The distribution of living lampreys (Petromyzoniformes) is antitropical, a feature almost certainly related to the fact that the ultimate incipient lethal temperature of ammocoetes lies between ~28 and 32 °C. In general, the species that attain the largest body size have the widest distribution. The holarctic species are placed in the Petromyzonidae, while those of the Southern Hemisphere are assigned either to the Geotriidae or Mordaciidae. Reference is made to the techniques used in lamprey systematics, placing particular emphasis on defining the terminology of the components of the dentition and the ways in which body proportions can be measured. Using dentitional characters, the Petromyzonidae can be arranged in a logical sequence from Ichthyomyzon and Petromyzon to either Caspiomyzon or to series consisting either of Eudontomyzon and Tetrapleurodon or the subgenera of Lampeira, i.e. Entosphenus, Lethenteron, and Lampetra. A list is given of the 17 parasitic and 22 nonparasitic lampreys described from the Northern and Southern hemispheres. The evolution of nonparasitic lampreys has involved an extension of larval life and a reduction in the postmetamorphic period, a process which has led to a marked reduction in the size of the mature adults. The more conspicuous differences between nonparasitic and parasitic species start to appear after the onset of metamorphosis. These include the rapid enlargement and maturation of gonads in nonparasitic species. However, significant differences have been found between the larvae of nonparasitic lampreys and those of their parasitic ancestor in such features as the number of oocytes, trunk myomeres, and size at the onset of metamorphosis.Key words: lampreys, life cycles, parasitic, nonparasitic, distribution, dentition, phylogeny, Petromyzonidae, Geotriidae, Mordaciidae