摘要:

Regression analyses have been used for over 2 decades to develop useful statistical relationships between estimates of fish catch and various members of a set of abiotic and biotic variables. In this study a number of conceptual and data refinements have been attempted with respect to certain lake data. More complete data are now available than was the case with earlier authors such as D. S. Rawson and R. A. Ryder. Rather than use average long-term catch, approximate estimates of maximum sustainable yield (MSY) were derived. The MSY of all species combined, Ct, was estimated as well as the MSY of a set of preferred taxa, Cs, comprising lake trout (Salvelinus namaycush) plus lake whitefish (Coregonus clupeaformis) plus walleye (Stizostedion vitreum) plus sauger (S. canadense). The most significant predictive relationships included only one independent variable, average dry weight of bottom fauna standing crop. which explained 83% of the variation of Ctper unit water area in a semilog relationship, and 80% of the variation of Ctper unit area and Csper unit area in log-log relationships. The best relationships incorporating solely abiotic variables included mean depth and total dissolved solids concentration as the only significant independent variables, and explained less than 70% of the variation. Other factors analyzed included the annual cumulative degree days above 5.6 C, the presence or absence of thermal stratification, and the average dry weight of net plankton standing crop.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<385:EPOFYO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A density-dependent function for the instantaneous fishing mortality rate is presented. It is shown that this function may be readily incorporated into the age-specific probability of survival in a Leslie-matrix population model.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<395:ADFFFM>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Time series data on catch and effort for the American lobster (Homarus americanus) from the state of Maine during the period 1933 to 1974, as well as mean annual sea surface temperatures for the same period were examined by means of a polynomial distributed lag model. The model was described and shown to be sufficiently flexible to take into account environmental influences over specific life history stages as well as over the entire life history of the species. The significance of lagged temperature effects and the fit of the model to the observed data were demonstrated.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<402:AOAPDL>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A catch survey of 502 km of the Missouri River was conducted from July 1, 1972 to June 30, 1973. The study area encompassed the Gavins Point Dam tailwaters (6.4 km), 84 km of unchannelized river and 412 km of channelized river. The fishery supported 412,660 angler hours (98,252 angling days) valued at $720,047. Anglers averaged 0.47 and 0.33 fish/h for annual catch and harvest rates, respectively. Catch rate includes fish not kept.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<412:TSFOTU>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The distribution and abundance of larval fish in a flood control reservoir were studied in the spring and summer of 1973, 1974, 1975, and 1976. Only gizzard shad larvae (Dorosoma cepedianum) were consistently collected in large numbers in the limnetic habitat. Gizzard shad larvae were more abundant at the upper than at the lower end of the reservoir. They concentrated at the surface during the day and dispersed from the surface at night. Bluegill larvae (Lepomis macrochirus) were relatively abundant in 1976 but were uncommon in 1975. They were more uniformly distributed throughout the reservoir than shad larvae and were no more abundant at the upper than at the lower end of the reservoir. Soon after yolk-sac absorption, at least a fraction of the bluegill larvae migrated into the limnetic zone and returned to the littoral zone after only a short interval.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<419:TDOLFL>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The Jolly-Seber model of mark-recapture analysis was used to gather information on seasonal or short-term changes in population size, survival rate, and recruitment of largemouth bass in a small pond. Tagged fish were recaptured significantly less often than fin-clipped fish. Based on fin-clipped fish, survival rates were higher from October 1973 to May 1974 and October 1974 to April 1975 (1.14 and 0.84) than from May to October 1974 (0.69). Growth was slower than the average bass population in Illinois.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<425:PDAGOA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Differences in seasonal patterns of growth, length at age, and diet were evident between brown trout (Salmo trutta) residing in geothermally heated and unheated sections of the Firehole River. Maximum temperatures at the warmest station exceeded 28 C and averaged about 10.5 C higher than the unheated station throughout the year. Scale characteristics indicated that brown trout from the heated stations had two annual growth periods while those from the unheated station had one, relatively short, annual growth period. Brown trout from the heated stations were significantly longer at any particular age than those from the unheated station. Caddis flies were the numerically dominant food in the unheated water while trout at the heated station fed most extensively on dipterans, molluscs, and mayflies. Additionally, trout in the unheated water fed almost entirely on immature benthic insects while those at the heated station fed heavily on emerging insects and exhibited considerably greater numbers of organisms per stomach. Rainbow trout (Salmo gairdneri), numerous only at the heated station, had seasonal growth pattern, length at age, and diet similar to those of brown trout at this station.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<432:GADOTF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

We compared the homing ability of three groups of rainbow trout (Salmo gairdneri) stocked in Lake Michigan by different procedures. One group of juvenile rainbow trout was imprinted to a synthetic chemical, morpholine, during the presmolt and smolt stages, and a second group was not imprinted. Both groups were stocked directly into Lake Michigan, 1 km north of the Little Manitowoc River. A third group of trout was retained in a pond on the Little Manitowoc River during the presmolt and smolt stages and then released into Lake Michigan at the same location as the other two groups. During the adult spawning migration, morpholine was metered into the Little Manitowoc River. This river and 16 other locations were monitored for returning fish. The morpholine-imprinted fish returned to the Little Manitowoc River in greater numbers and strayed less than did fish from the other two treatment groups. This result is a consequence of exposure to a unique odor cue at the critical period for imprinting.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<439:HORTTI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Approximately 500 Paiute trout inhabited 2 out of 5.3 km of available stream during the summer of 1974. Distribution of fish was determined by mark-recapture, trapping, and visual observations; there was little large-scale movement. Twenty-one fish were transplanted within the stream to an unpopulated section, and 15 were recaptured there after 2 months. During this time, only four fish moved into the donor area of the stream. Transplantation was successful; therefore, habitat quality was probably not inhibiting fish occupation of most vacant stream areas. Slow dispersal of this population of fish appears to be limiting its distribution within the stream.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<444:TMADOP>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Biological studies of the hogchoker, Trinectes maculatus, were conducted in the lower Hudson River, New York. Scales were formed on individuals by the time they were 10 mm total length. Annulus formation occurred between April and June, and false annuli were noted occasionally. Growth of T. maculatus was rapid during the first 2 years of life. Females grew larger and older than males, but sexual maturity occurred as early as 2 years of age for both sexes. The sex ratio was 1:1 and major spawning occurred in midsummer. The length-weight relationships of male and female hogchokers did not differ significantly and the resulting equation for 2,692 specimens was W = 0.015108 L3.10845, where W = weight (g) and L = total length (mm). Fish length at time of annulus formation was similar to that reported for Patuxent River, Maryland specimens. Size at maturity may occur earlier and spawning each year may occur over a longer period of time for hogchokers in the Hudson River compared to individuals in mid-Atlantic coastal areas.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<449:AGAMOT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor