Showing papers in "Canadian Journal of Fisheries and Aquatic Sciences in 1988"
TL;DR: A large number of mechanisms controlling recruitment in fishes are unknown and the literature on recruitment mechanisms is large and growing rapidly, but it is unclear how these mechanisms are influenced by environmental influences.
Abstract: Understanding the mechanisms controlling recruitment in fishes is a major problem in fisheries science. Although the literature on recruitment mechanisms is large and growing rapidly, it is primari...
1,288 citations
TL;DR: This work presents sampling designs for estimating total areas of habitat types and total fish numbers in small streams and applies designs applied independently within strata constructed on the basis of habitat ...
Abstract: We present sampling designs for estimating total areas of habitat types and total fish numbers in small streams. Designs are applied independently within strata constructed on the basis of habitat ...
440 citations
TL;DR: Of the biological measures tested, species richness, local indicator species, abundance of large piscivores, fish abundance, and incidence of blackspot disease were found to contribute significantly to IBI estimates.
Abstract: A multivariate measure of stream quality, the Index of Biotic Integrity (IBI), was adapted to southern Ontario and calibrated to watershed land use on a variety of spatial scales. The fish fauna at 209 stream locations on 10 watersheds near Toronto, Ontario, was sampled with a backpack electrofisher in the summers of 1984 and 1985 to provide biological information for the IBI. Watershed urbanization, forest cover, and riparian forest were measured from 1:50,000 scale topographic maps and related to IBI estimates by linear regression. Of the biological measures tested, species richness, local indicator species (brook trout (Salvelinus fontinalis) and Rhinichthys spp.), abundance of large piscivores, fish abundance, and incidence of blackspot disease were found to contribute significantly to IBI estimates. Variation in IBI estimates at the same location ranged from 0 to 8% within the sample season and from 0 to 24% between years. Linear models based on measures of watershed urbanization and forest cover acc...
367 citations
TL;DR: It was found that otolith growth rate expressed as daily increase in weighings in Arctic char fry fed maximum rations was found, with exponential relationships between otolith weight and fish wet weight showing exponential relationships.
Abstract: Experiments were conducted to study the effect of temperature, fish size, and somatic growth rate on mean daily otolith growth rate in Arctic char (Salvelinus alpinus) fry fed maximum rations. Long...
328 citations
TL;DR: Results of the investigation show profound effects of BKME on several fundamental biochemical and physiological functions, including reduced gonad growth, enlarged liver, and very strong induction of certain cytochrome P-450-dependent enzyme activities in the liver.
Abstract: An extensive trial to examine physiological and biochemical changes in perch (Perca fluviatilis) inhabiting coastal waters polluted by bleached kraft mill effluents (BKME) has been carried out. The investigations were performed at four different times of year. Fish from a reference site and from sampling sites 2, 4.5, 8, and 10 km from the discharge point were examined. The results of the investigation show profound effects of BKME on several fundamental biochemical and physiological functions. Typical symptoms in perch from the polluted areas were reduced gonad growth, enlarged liver, and very strong induction of certain cytochrome P-450-dependent enzyme activities in the liver. Elevated levels of ascorbic acid in liver tissue and abnormal carbohydrate metabolism reflect the effluent's ability to cause metabolic disorders. Marked effects on the white blood cell pattern indicate a suppressed immune defence. Alterations in the red blood cell status and in the ion balance suggest that the demand for oxygen ...
317 citations
TL;DR: Analysis of literature data from lakes worldwide showed significant relationships between the release rates and total sediment P and citrate dithionite bicarbonate extractable P and reductant-soluble P.
Abstract: Release rates of phosphorus from anoxic sediment surfaces in seven North American lakes were determined from core tube incubations. These rates were compared with several P fractions within the 0–5...
304 citations
TL;DR: Although size-selective predation has been an important phenomenon in stimulating widespread research on effects of fish on freshwater communities and their function, the importance of other mechanisms in such regulation is considered.
Abstract: The role of fish in regulation of the structure and function of freshwater ecosystems (lakes and streams) is examined with respect to effects resulting directly from their feeding activity, indirec...
290 citations
TL;DR: Atlantic cod, Gadus morhua, were maintained on different ration levels or starved to produce a variety of growth rates to determine the in vivo rates of protein synthesis and degradation.
Abstract: Atlantic cod, Gadus morhua, were maintained on different ration levels or starved to produce a variety of growth rates. The in vivo rates of protein synthesis and degradation were determined for th...
264 citations
TL;DR: The study of environmental effects on fish distributions and recruitment rates has become a major research focus with substantial funding, but this research is justified by rather vague claims about understanding the causes of variability and making more accurate predictions based on this understanding.
Abstract: The study of environmental effects on fish distributions and recruitment rates has become a major research focus with substantial funding. This research is justified by rather vague claims about un...
254 citations
TL;DR: Clear-cut logging of 41% of the basin of Carnation Creek, British Columbia, resulted in increased stream temperatures in all months of the year, increases above prelogging temperatures ranged from ...
Abstract: Clear-cut logging of 41% of the basin of Carnation Creek, British Columbia, resulted in increased stream temperatures in all months of the year, increases above prelogging temperatures ranged from ...
253 citations
TL;DR: Measures of thermal habitat space were developed by integrating, over time during the summer period, the amount of lake bottom area and pelagic volume with water temperatures within species' optimal thermal niches within species', using R. A. Ryder's morphoedaphic index.
Abstract: Measures of thermal habitat space were developed by integrating, over time during the summer period, the amount of lake bottom area and pelagic volume with water temperatures within species' optimal thermal niches. These species' specific measures, thermal habitat area, THA (hectares per 10 d), and thermal habitat volume, THV (cubic hectometres per 10 d), were used as predictor variables in regression equations estimating the total sustained yield, SY (kilograms per year), of each of four commercially important species: lake trout, Salvelinus namaycush; lake whitefish, Coregonus Clupeaformis; walleye, Stizostedion vitreum vitreum; and northern pike, Esox lucius. One or both of THA and THV were strongly correlated with SY for each of the four species for a set of 21 large north-temperate lakes. Several other habitat variables were assessed with respect to species' SY: total lake area and volume, mean depth, total dissolved solids, and the ratio of the latter two as R. A. Ryder's morphoedaphic index. The va...
TL;DR: For both species, and for immature and mature fish, lipid levels were lowest (and water content highest) in winter. as discussed by the authors showed that early winter was the harshest season for wild brook trout.
Abstract: Proximate body composition and hematological parameters of wild brook (Salvelinus fontinalis) and brown trout (Salmo trutta) from five sites were monitored over three winters. For both species, and for immature and mature fish, lipid levels were lowest (and water content highest) in winter. Lipid levels were most rapidly depleted (to between 2 and 4% wet weight) in early winter (November–December). Brown trout and immature brook trout appeared to suffer a second period of depletion in late winter (February–March) in contrast with spent brook trout. Protein and ash components were relatively stable between dates. Serum protein levels varied greatly but generally indicated a decline in early winter from high summer (August) values prior to increasing in May. Such trends were most obvious during the winter of 1983–84, the harshest of the three winters of study. In the winter, serum glucose concentrations peaked in November. These physiological relationships corroborate earlier findings that early winter is a...
TL;DR: The two most common ways of estimating fish growth use age–length data and tagging data but it is shown that growth parameters estimated from these two types of data have different meanings and thus a new approach is needed.
Abstract: The two most common ways of estimating fish growth use age–length data and tagging data. It is shown that growth parameters estimated from these two types of data have different meanings and thus a...
TL;DR: A review of literature about the suspected competition between brook trout and rainbow trout in streams reveals that despite empirical evidence that water temperature and velocity play a critical interacting role in determining the outcome, evidence of interspecific competition between other pairs of stream salmonids has not been rigorous.
Abstract: Salmonids have been introduced worldwide to regions where they were not indigenous, usually without considering the effects on native species. This has led to many combinations of species in unnatu...
TL;DR: Underwater observations at two sites along a small Nova Scotian river were carried out between December and April to describe the winter microhabitat of young Atlantic salmon to suggest a nocturnal activity pattern and photonegative response by young salmon during winter.
Abstract: Underwater observations at two sites along a small Nova Scotian river were carried out between December and April (water temperature range = 0.5–7.0 °C) to describe the winter microhabitat of young...
TL;DR: Levels of genetic variation were measured in first-generation Atlantic salmon cultured for stock enhancement programs in eastern Canada and compared with variation in wild stocks, consistent with a loss of genetic variability in the hatchery salmon from random drift caused by using small numbers of salmon for broodstock.
Abstract: Levels of genetic variation were measured in first-generation Atlantic salmon (Salmo salar) cultured for stock enhancement programs in eastern Canada and compared with variation in wild stocks. One regulatory and 19 structural protein loci were screened of which 10 were polymorphic. Mean heterozygosity and number of alleles per locus were positively correlated with the effective number of adults (N) used to establish the hatchery groups and averaged 26 and 12% lower, respectively, than wild stocks. The observations are consistent with a loss of genetic variability in the hatchery salmon from random drift caused by using small numbers of salmon for broodstock.
TL;DR: In this article, multivariate analyses of biotic assemblages and physicochemical measures, species richness, diversity, and composition were used to evaluate the robustness of Omernik's ecoregion classification for small streams in the eight ecoregs of Oregon.
Abstract: Multivariate analyses of biotic assemblages and physicochemical measures, species richness, diversity, and composition were used to evaluate the robustness of Omernik's ecoregion classification for small streams in the eight ecoregions of Oregon. Clearest differences were between the montane and nonmontane regions. For the three nonmontane regions, ordinations of fishes, macroinvertebrates, water quality, and physical habitat measures show the clearest differences, with the Willamette Valley ecoregion being consistently most unlike all other regions. Differences between the Columbia Basin and High Desert regions were clearest for water quality and physical habitat measures and fish assemblages. Differences among the montane regions were subtle. Of these regions, the East Cascade Slopes showed the greatest variability, as shown by the ranges of ordination scores for fishes, water quality, and physical habitat. Regional patterns in periphyton assemblages were markedly different from the patterns in the othe...
TL;DR: A decade of data on wild steelhead trout (Salmo gairdneri) from a coastal stream in British Columbia demonstrated large fluctuations in smolt number, age structure, size, estimates of adult run sizes, smolt-to-adult survival, and adult age.
Abstract: A decade of data on wild steelhead trout (Salmo gairdneri) from a coastal stream in British Columbia demonstrated large fluctuations in smolt number, age structure, size, estimates of adult run sizes, smolt-to-adult survival, and adult age. Adult runs averaged 922 (range 209–2730) with approximately 10% repeat spawning incidence. Females repeat spawned more than males and were more abundant as kelts, but maiden run adults were equally male and female. The proportion of males returning after 1, 2, and 3 yr in the ocean averaged 3, 62, and 35%, respectively; 58 and 42% of females returned after 2 and 3 yr, respectively. Adult age structure, smolt number, and smolt size varied biennially. Adult size decreased with freshwater age, but increased with ocean age of returns. Males were larger at each ocean age. Mean number of smolts (50:50 sex ratio) was 5543 and varied fivefold. Mean smolt length was 173 mm and mean weight was 49 g. Smolts were 2–5 yr old, and freshwater age 3 was most prevalent (average 56%). M...
TL;DR: Here it is provided proof that the causative agent, domoic acid, is indeed produced by this diatom, Nitzschia pungens, a widely distributed diatom not previously known to produce toxins.
Abstract: During late 1987, an outbreak of poisoning resulting from the ingestion of cultivated blue mussels (Mytilus edulis) from a localized area in eastern Canada (Cardigan Bay, Prince Edward Island) was ...
TL;DR: Seasonal changes in solar insolation had no effect on the autotrophic community growth rates in unamended river water and temperature exerted the most dominant influence on phosphorus-replete growth rates.
Abstract: Phosphate enrichment experiments were conducted year-round at the experimental troughs research apparatus (EXTRA) on the South Thompson River in British Columbia to determine the relationship between external concentration of orthophosphate and the growth rates of lotic periphytic diatom communities. Growth rate saturation always occurred at a phosphate concentration of approximately 0.3–0.6 μg P∙L−1. The maximum growth rate (μmax-P) with phosphorus enrichment varied seasonally with temperature. The relative specific growth rates (μ:μmax-P) as a function of external phosphate were constant. Seasonal changes in solar insolation (PAR) had no effect on the autotrophic community growth rates in unamended river water. Temperature exerted the most dominant influence on phosphorus-replete growth rates.
TL;DR: Study results indicate that riparian trees must be left to grow longer than 50 yr to ensure that an adequate, long-term supply of woody debris is available to stream channels.
Abstract: Large quantities of woody debris persisted 50 yr after logging and fire in stream channels of a small coastal Oregon watershed. Debris from the current stand represented only 14% of total debris vo...
TL;DR: Female English sole from the heavily contaminated sites were significantly less likely to undergo gonadal recruitment and liver tissue was examined histologically for the presence of suspected toxicopathic lesions.
Abstract: In a study evaluating the effects of exposure to xenobiotic compounds on ovarian development in English sole (Parophrys vetulus), prespawning females were sampled from four sites in Puget Sound, Washington, during the 1986 and 1987 spawning seasons. Two sampling sites had high concentrations of xenobiotic compounds in the sediment, while the other sites were less contaminated. The following factors associated with ovarian maturation were measured: ovarian developmental stage, ovarian atresia, gonadosomatic index, plasma estradiol, and plasma vitellogenin as estimated from alkali-labile phosphorus. Contaminant exposure was assessed by measuring concentrations of fluorescent aromatic compounds in the bile, hepatic aryl hydrocarbon hydroxylase (AHH) activity, and hepatic polychlorinated biphenyl levels, and liver tissue was examined histologically for the presence of suspected toxicopathic lesions. Female English sole from the heavily contaminated sites were significantly less likely to undergo gonadal recru...
TL;DR: Rainbow trout, Salmo gairdneri, were fed purified diets with zinc concentrations ranging from deficient to excessive (1, 90, 590μg Zn∙g−1) and simultaneously exposed to a range of waterborne [Zn]...
Abstract: Rainbow trout, Salmo gairdneri, were fed purified diets with zinc concentrations ranging from deficient to excessive (1, 90, 590 μg Zn∙g−1) and simultaneously exposed to a range of waterborne [Zn] ...
TL;DR: Comparison of growth rates and resource densities suggests that the growth rates of the laolinic sunfish are influenced more by unique lake differences than by annual climatic differences.
Abstract: Size-specific growth rates were determined for bluegill (Lepomis macrochirus) and pumpkinseed (L. gibbosus) sunfish collected between 1978 and 1985 in nine lakes in southwestern Michigan. Variation in growth rates was attributable to lake effects as well as an interaction between lake and year effects. Year effects explained none of the observed variation, suggesting that growth rates were influenced more by unique lake differences than by annual climatic differences. Analyses of the covariation in growth among different size-classes of bluegill and pumpkinseed revealed that small bluegill ( 55 mm SL) and large pumpkinseed (> 50 mm SL) responded differently. These breaks in the growth patterns coincide with the sizes at which each species exhibits an ontogenetic shift in diet. Comparison of growth rates and resource densities suggests that the growth rates of the la...
TL;DR: Adult and juvenile rainbow trout, Salmo gairdneri, acclimated to high and low water Ca levels were statically exposed to equimolor concentrations of Cd or Cu at circumneutral pH or pH 4.8 either alone or in metal/H+ combinations for 24 h.
Abstract: Adult and juvenile rainbow trout, Salmo gairdneri, acclimated to high and low water Ca levels were statically exposed to equimolor concentrations (~ 6.5 μmoluL−1) of Cd or Cu at circumneutral pH or pH 4.8 either alone or in metal/H+ combinations for 24 h. Unidirectional fluxes of Ca2+ and Na+ were measured by means of radiotracers and terminal blood samples were drawn for analysis of Ca2+ and Na+. Plasma Ca2+ was found not to be a reliable indicator of disturbances in branchial Ca2+ fluxes. Cadmium specifically inhibited Ca2+ influx, while having no effect on Ca2+ efflux and only minor effects on Na+ fluxes. The inhibition of Ca2+ influx by Cd was modulated by water Ca2+ content. Copper altered net Na+ flux and plasma Na+ in trout, while having only a transient effect on Ca2+ homeostasis, the effects of Cu on the net Na+ fluxes of trout were not modulated by either water Ca2+ or pH. Hydrogen ion perturbed Ca2+ dynamics predominantly by stimulating Ca2+ efflux, while reducing influx only slightly. Exposure...
TL;DR: In this paper, the abundance of phytophilous invertebrates was measured in 13 macrophyte beds and was related, using multiple regression analysis, to the biomass of macrophytes among which the invertebrate were collected, the average plant biomass growing per unit lake area, water and organic matter content of the sediments, total phosphorus concentration in the water, rooting depth of the microphyte bed, and sampling date.
Abstract: The abundance of phytophilous invertebrates was measured in 13 macrophyte beds and was related, using multiple regression analysis, to the biomass of macrophytes among which the invertebrates were collected, the average plant biomass growing per unit lake area, water and organic matter content of the sediments, total phosphorus concentration in the water, rooting depth of the macrophyte bed, and sampling date. Quantitative analyses are presented for chironomids, cladocerans, cyclopoid copepods, gastropods, water mites (Hydracarina), ostracods, and trichopterans. R2 values for the regression equations ranged from 0.43 to 0.81. The abundance of invertebrates was best related to the biomass of separate plant species, but equations based only on total plant biomass sometimes had equivalent R2 values, in general, the abundance of phytophilous invertebrates was positively related to areal plant biomass, sediment organic matter, and lake trophic status and negatively related to depth. The abundance of phytophilo...
TL;DR: This work tested Hjort's and Lasker's hypotheses that the abundance of recruits in fishes is determined at an early life stage by using data on components of population dynamics of the well-studied fishes.
Abstract: We tested Hjort's and Lasker's hypotheses that the abundance of recruits in fishes is determined at an early life stage. Using 13 yr of data on components of population dynamics of the well-studied northern anchovy (Engraulis mordax), we reconstructed the abundance of anchovy in each year at three stages: eggs, 4.5-d-old yolk-sac larvae, and 19-d-old larvae. No abundance measure was significantly correlated with age 1 recruits, resulting in rejection of Hjort's and Lasker's hypotheses. We give reasons why the low correlations are not an artifact of estimation error. The lack of correlation exists because of the large variability (CV = 171%) in survival rate between age 19 d and age 1 yr. Therefore, attempts to understand interannual variability in recruitment in this, and perhaps other, marine fish species may have to rely not only on data on eggs and larvae, but especially on data on abundances estimated after 20 d, closer to the age at recruitment.
TL;DR: Adult brook trout (Salvelinus fontinalis) were exposed for up to 11 d to one of a matrix of 18 Al, low pH, and Ca2+ combinations, chosen as representive of acidified softwater environments in the wild, and losses arose from inhibition of influx and stimulation of efflux.
Abstract: Adult brook trout (Salvelinus fontinalis) were exposed for up to 11 d to one of a matrix of 18 Al, low pH, and Ca2+ combinations, chosen as representive of acidified softwater environments in the w...
TL;DR: Winter floods in the Sierra Nevada mountains kill age 0 class brook trout and Paiute sculpin because bed-material transport increases greatly when high flows are constrained by snow banks.
Abstract: Winter floods in the Sierra Nevada mountains kill age 0 class brook trout (Salvelinus fontinalis) and Paiute sculpin (Cottus beldingi) because bed-material transport increases greatly when high flows are constrained by snow banks. In February 1982, dead Paiute sculpin were collected while sampling bedload during a rain-on-snow flood. Population estimates by electrofishing at nine permanent stations the following summer showed that density (3586∙ha−1) and biomass(12.9 kg∙ha−1) of Paiute sculpin were lower than the respective means (12 017∙ha−1 and 40.3 kg∙ha−1) obtained during previous studies from 1952 to 1961. These estimates were also below those obtained in 1956, after the largest winter flood from 1952 to 1961. Brook trout fry were also less abundant in 1982 than previously reported. Maximum flow depth, rather than discharge, were the likely cause offish mortality. Winter floods are severe because accumulated snowpack increases the effective height of the streambank and confines most or all of a rain-...
TL;DR: The results indicate that piscivorous and planktivorous charr belong to the same gene pool; piscive charr are probably recruited from the most fast-growing planktIVorous individuals and start feeding on fish at a length of 23 cm.
Abstract: The Arctic charr (Salvelinus alpinus) in Thingvallavatn, Iceland, exhibits four morphs. Small benthivorous charr grow slowly, have an asymptotic length of 13 cm, and mature at an age of 2–4 yr. Large benthivorous charr grow faster and almost rectilinearly with age. They mature at an age of 3–11 yr. Planktivorous and piscivorous charr have even higher initial growth rate, but planktivorous charr cease growing at 20 cm and piscivorous charr at a fork length of 30 cm. They mature at 3–5 yr and 5–10 yr of age, respectively. The gonadosomatic index and the annual allocation of energy into gonads relative to soma were higher for planktivorous and piscivorous than for benthivorous charr. The results indicate that piscivorous and planktivorous charr belong to the same gene pool; piscivorous charr are probably recruited from the most fast-growing planktivorous individuals and start feeding on fish at a length of 23 cm. The benthivorous morphs may belong to different stocks due to significant differences in several...