ISSN:0002-8487    

DOI:10.1577/1548-8659-119.1.1

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The Fish Genetics Section of the American Fisheries Society established its Nomenclature Committee to develop and promote standardized genetic nomenclatures. Here, following public comments on previously published draft guidelines, we present the committee's revised version of a nomenclature for protein-coding loci in fish. This nomenclature closely parallels the one used for human genetics, but improves on it in several respects. The fish system (1) includes standardized abbreviations for commonly analyzed proteins, and provides formal symbols for gene loci encoding these proteins; (2) specifies typographic conventions for distinguishing between genes and proteins and for identifying alleles; (3) provides for multilocus isozyme systems, isoloci, regulatory loci, and pseudogenes; (4) allows important basic information (such as subcellular distributions of gene products, active substrate isomers, recent gene duplicates, and orthologous relationships among loci) to be specified in gene symbols via prefixes, suffixes, and multilocus designations; (5) provides three alternative systems of allele designation and distinguishes alleles having quantitative effects; and (6) includes guidelines for specifying genotypes, linkage relationships, and biochemical phenotypes. This nomenclature is intended to be comprehensive, flexible, unambiguous, and applicable to all fish species as well as to other organisms. The American Fisheries Society has adopted this system as an editorial standard for its publications.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0002:GNFPLI>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

In the Columbia River, we found the diet of subyearling chinook salmonOncorhynchus tshawytschato be predominately caddisflies (Trichoptera; 64% by weight) in riverine nursery habitats, but mostlyDaphniaspp. and terrestrial insects in reservoir habitats. A preference analysis indicated that subyearlings did not eat food items in proportion to food availability; they preferred small zooplankters least and terrestrial insects most. Rank in preference of food items was correlated positively with rank in size of available food items, but not with rank in number in the diet. Only rank in number of prey items available in the habitat was consistently correlated with rank in number in the diet. The shift in diet toDaphniaspp. and terrestrial insects in the reservoir was due primarily to the high availability of those food items and the low availability of others. The switch to food items abundant in reservoirs enabled subyearling chinook salmon to use the reservoirs as nursery areas. However, the use ofDaphniaspp. may entail a higher foraging cost per energy unit gained because of the small size of the prey.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0016:FEOSCS>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Infectious hematopoietic necrosis is generally considered a disease of salmonid alevins, fry, and early juveniles. It has been suggested that this disease kills only young salmonids and that susceptibility decreases with increased size and age of the fish. To determine if decreased susceptibility occurs with increasing size, we exposed four different sizes of rainbow troutOncorhynchus mykiss(mean weight, 0.2–13.1 g) and kokanee (lacustrine sockeye salmon)Oncorhynchus nerka(0.2–7.2 g) to two waterborne strains of infectious hematopoietic necrosis virus. Both species were exposed to four concentrations of a type-1 virus strain, which was isolated from fish in Oregon, and a type-2 virus strain obtained from fish in Idaho. Neither strain of virus was consistently more virulent over all exposure concentrations for kokanee at the 0.2-g fish size, At all other sizes, kokanee were consistently more susceptible to the Oregon strain than to the Idaho strain (sign test,P< 0.002). Conversely, all sizes of rainbow trout were consistently more susceptible to the Idaho strain than to the Oregon strain (sign test,P< 0.001). The results showed that there are differences in virulence for type-1 and -2 strains of virus and that these strains have the ability to produce disease in kokanee and rainbow trout as large as 7.2 g and 13.1 g, respectively.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0025:SSOSTT>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Channel catfishIctalurus punctatuswere reared for 2 years on practical feeds with and without a topdressing of oil (50% animal, 50% vegetable). Visceral fat, fillet fat, and whole-body protein increased and moisture percentage decreased as fish size and age increased. Slopes of regression lines for these variables differed significantly between treatments. Fatty acid profiles of fillets showed essentially linear trends toward decreasing saturation and increasing unsaturation with increasing size and age of fish. Within the unsaturated fatty acids, monene levels increased, and diene and triene levels decreased. Topdressing with oil did not affect these trends. Although dietary lipid composition is a major influence on fatty acid composition in channel catfish, this study indicates that fish size and age also significantly influence fatty acid profiles.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0031:CIPAFA>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

We have recently developed a new estimator of recreational fishing effort. Here we used a simulation model to determine and demonstrate the statistical behavior of this new estimator. The estimator is used with access-intercept surveys and was designed to give accurate, efficient estimates of fishing effort over a geographically large and diverse fishery. Because this is a new estimator, little is known about its behavior. Specifically, the form of the estimator's sampling distribution, the variance components (within-day versus between-day), and itst-distribution were unknown and could not be determined analytically. Hence, to assist people who will want to know the statistical properties of this estimator and to characterize it more completely, we studied its behavior numerically by use of a simulation model based on real-world data. Analysis of the simulation results showed the sampling distribution of the estimator to be non-normal when limited to a single survey route; it was more closely approximated by a gamma distribution. The estimator approached normality when used to estimate effort from multiple-route (large-scale) fisheries with greater fishing effort. Within-day variance (influenced by starting position along the route and direction of travel) was larger than the between-day (day-to-day) variability. Because the sampling distribution of the estimator was non-normal, thet-distributions were generated empirically to determine the direction and degree of misspecification when the usual Studentt-distribution was used. Use of the Studenttresulted in slightly skewed ∝ values with too large a probability of inclusion in the lower tail and too small a probability in the upper tail.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0041:UOACSM>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

We analyzed genetic variation in 35 populations of Chinook salmonOncorhynchus tshawytschafrom northern California by use of allozymes detected by horizontal starch gel electrophoresis. Products of 53 loci from 27 enzyme systems were used to characterize the genetic structure, assess hierarchical relationships, and estimate levels ofgene flow among the populations. Average heterozygosity, 0.038, and percent polymorphic loci, 41 %, found in California populations were similar to previously reported values from more northern locations. Ten hatchery populations were included in the analysis and generally possessed levels ofgenetic variability similar to nearby wild populations. Although estimated average gene flow was 1.16, high from an evolutionary standpoint, and genetic identities were greater than 0.990, we observed genetic differentiation among populations. Distribution of specific alleles, cluster analysis based on genetic identity estimates, and gene diversity analyses indicated that inland populations ofCalifornia Chinook salmon were genetically differentiated by drainage and river system. Coastal populations did not cluster geographically. We suggest that founder effects and population bottlenecks after frequent volcanic activity are mechanisms leading to different levels ofgenetic variability within California. Whereas extensive glaciation during the Pleistocene displaced many salmon populations in Washington and Canada, glacial activity in California was restricted to higher elevations. Therefore, drainage patterns and Chinook salmon populations remained intact during this period. We propose that these differences in the distribution and extent of glacial activity in North America during the Pleistocene may account for more subpopulation structure in California than in more northern areas.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0055:GSAGFI>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Summer mortality of adult striped bassMorone saxatilisin reservoirs has been hypothesized to be associated with a temperature-oxygen squeeze, i.e., the temperature of the oxygenated surface water becomes too high and the dissolved oxygen concentration in deep, cool areas becomes too low for striped bass. We evaluated this hypothesis by monitoring mortality, water quality, and the habitats occupied by striped bass in a reservoir where summer mortality of this species is common. During summer, striped bass were restricted to a thin (1–2-m) layer of the stratified water column consisting of the coolest waters available at which dissolved oxygen concentrations exceeded 2 mg/L. Fish seemed to stop feeding when minimum temperatures in this layer reached about 27°C. No mortality occurred during summer 1986, when temperatures in the oxygenated layer reached a maximum of 28.0°C and remained above 27°C for about 1 month. Mortality did occur in 1987, when temperatures peaked at 29.3°C and remained above 27°C for about 1 month, and in 1988, when temperatures peaked at 28.3°C and remained above 27°C for about 7 weeks. These observations suggest that adult striped bass can tolerate exposure to 27–28°C for about 1 month, but die (probably of malnutrition) when they are exposed to slightly higher temperatures (≈29°C) for a similar period or when exposure to 28°C is prolonged.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0072:LCAWSM>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Stocks of Atlantic striped bassMorone saxatilisthat were assumed to be geographically isolated during spawning showed strong antigenic differences in blood serum albumin. A discriminant function was estimated from the immunologic responses of northern (Canadian and Hudson River) and southern (Chesapeake Bay and Roanoke River) stocks to two reference antisera. The function correctly classified 92% of the northern and 95% of the southern fish in the training set. Cross-validation revealed similar percentages of correct classification for fish that were of known origin but not used to estimate the discriminant function. Monte Carlo experiments were used to evaluate the ability of the discriminant function to predict the relative contribution of northern fish in samples of various size and stock composition. Averages of predicted proportions of northern fish in the samples agreed well with actual proportions. Coefficients of variation (100 × SD/mean) in the predicted proportions ranged from 1.5 to 36% for samples of 50–400 fish that contained at least 10% northern stock. In samples that contained only 2% northern stock, however, at least 1,600 fish were required to achieve similar levels of precision.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0077:IDOASB>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

We used underwater video in conjunction with the line transect method and a Fourier series estimator to make 13 independent estimates of the density of known populations of bricks lying on the bottom in shallows of Lake Huron. The pooled estimate of density (95.5 bricks per hectare) was close to the true density (89.8 per hectare), and there was no evidence of bias. Confidence intervals for the individual estimates included the true density 85% of the time instead of the nominal 95%. Our results suggest that reliable estimates of the density of objects on a lake bed can be obtained by the use of remote sensing and line transect sampling theory.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0086:EOLTSB>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor