Evaluation of Trawls for Monitoring and Harvesting Fish Populations in Lake Oahe, South Dakota PDF Download
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Author: William Roland Nelson Publisher: ISBN: Category : Fish populations Languages : en Pages : 16
Book Description
Trawls of various designs and sizes were compared to evaluate their use for monitoring and harvesting fish populations in Lake Oahe. Catches of a 20.7-m semiballoon trawl, selected to monitor changes in the fish populations from 1965 to 1970, showed a downward trend in the abundance of all species, except walleye; the decline was largest in the lower area of the reservoir with a slight increase in the upper area. Of two trawl designs tested, semiballoon trawls captured more fish per hour than high-rise trawls, and a 15.9-m semiballoon trawl with a 3.8-cm mesh cod end captured fish at the highest and most consistent rate. The size and species composition of the fish caught in small-mesh trawls differed from thos caught in trap nets. Trawl cataches were too small to recommend or warrant their use as a commercial fishing gear, but the use of both small mess trawls and trap nets should improve accuracy in monitoring fish populations in this reservoir.
Author: William Roland Nelson Publisher: ISBN: Category : Fish populations Languages : en Pages : 16
Book Description
Trawls of various designs and sizes were compared to evaluate their use for monitoring and harvesting fish populations in Lake Oahe. Catches of a 20.7-m semiballoon trawl, selected to monitor changes in the fish populations from 1965 to 1970, showed a downward trend in the abundance of all species, except walleye; the decline was largest in the lower area of the reservoir with a slight increase in the upper area. Of two trawl designs tested, semiballoon trawls captured more fish per hour than high-rise trawls, and a 15.9-m semiballoon trawl with a 3.8-cm mesh cod end captured fish at the highest and most consistent rate. The size and species composition of the fish caught in small-mesh trawls differed from thos caught in trap nets. Trawl cataches were too small to recommend or warrant their use as a commercial fishing gear, but the use of both small mess trawls and trap nets should improve accuracy in monitoring fish populations in this reservoir.
Author: Hugh A. Poston Publisher: ISBN: Category : Fish-culture Languages : en Pages : 20
Book Description
Manipulation of photoperiods, combined with modifications by other environmental conditions such as temperature and salinity, can alter growth, smoltification, and sexual maturation of salmonid fishes by way of a neuroendocrine pathway. The extent of responses of salmonids to environmental changes, however, is restricted by circadian endogenous metabolic rhythms that cannot be completely overcome by external factors. The success of the manipulation of photoperiod depends primarily on four factors: the daily length and the duration of the light treatment; the season and time of day during which fish are exposed to light; the age, sex, size and species of fish; and the type of physiological response under consideration. Although gaps remain in the available information, salmonids apparently need systematically changing, intermittent periods of darkness for optimum long-term stimulation of growth, reproduction, and migration.
Author: LaRue Wells Publisher: ISBN: Category : Fishes Languages : en Pages : 20
Book Description
Stomachs of 1,064 alewives, 1,103 yellow perch, 246 spottail shiners, 288 trout-perch, 454 slimy sculpins, and 562 fourhorn sculpins from Lake Michigan were examined for food contents. Fish were sampled primarily from March to November and nearly all were caught at the bottom in the southeastern part of the lake near Saugatuck, Michigan. Pontoporeia was the most commonly reprented food item in the stomach contents of the fish examined, with immature midges, Mysis (a type of freshwater shrimp), copepods, cladocerans, fingernail clams and crayfish also being represented. Different species consumed different proportions of foods. Zooplankton was the principle food of alewives and spottail shiners, but was also consumed in small quantities by yellow perch and trout perch. Mysis was important to fourhorn sculpins, in addition to Pontoporeia. Immature midges were a major portion of spottail shiners and trout perch, also being consumed by alewives. Fish were often the most important food of yellow perch in the largest size category. Crayfish were a sizable portion of the diet of yellow perch on rocky bottoms, but sparingly on smooth bottoms. Spottail shiners also ate substantial numbers of fingernail clams.
Author: D. F. Woodward Publisher: ISBN: Category : Cutthroat trout Languages : en Pages : 12
Book Description
Two formulations of the herbicide 2,4-D (2,4-dichlorophenoxyacetic acid) - the butyl ester (BE) and the propylene glycol butyl ether ester (PGBEE) -- had 96-h LC50's to cutthroat trout and lake trout ranging from 490 to 1,200 microgram/liter in static tests. A third formulation -- the isooctyl ester (IE) -- was not toxic to cutthroat trout or lake trout at concentrations below 60.000 microgram/liter. The butyl ester (2,4-D BE) was slightly more toxic than 2,4-D PGBEE, and the toxicity of both esters increased as water temperature decreased.
Author: James Walter Morton Publisher: ISBN: Category : Dredging Languages : en Pages : 44
Book Description
The goal of this study was to prepare a comprehensive review of the literature on the physical, chemical, and biological effects of dredging and spoil disposal in estuaries and to identify alternative spoil disposal methods. Specific objectives were to identify the most critical problems relating to dredging and spoil disposal and to summarize the progress made to date in solving these problems. Using literature search facilities, bibliographies, and communications with experts throughout the United States, about 520 scientific and technical articles on dredging and spoil disposal were screened. Information extracted from selected articles is included in this review.
Author: Roy F. Heberger Publisher: ISBN: Category : Biochemical oxygen demand Languages : en Pages : 24
Book Description
Samples of crustacean zooplankton were collected monthly in west-central Lake Erie in April and June to October 1968, and in July and August 1970, before and during periods of hypolimnetic dissolved oxygen (DO) depletion. The water column at offshore stations was thermally stratified from June through September 1968, and the hypolimnion contained no DO in mid-August of 1968 or 1970. Composition, abundance, and vertical distribution of crustacean zooplankton changed coincidently with oxygen depletion. Zooplankton composition shifted from mainly cyclopoid copepods in July to mainly cladocerans and copepod nauplii in middle to late August. We believe that mortality of adults and dormancy of copepodites in response to anoxia was the probable reason for the late summer decline of planktonic C. b. thomasi.
Author: William H. Berlin Publisher: ISBN: Category : Fishes Languages : en Pages : 12
Book Description
Eggs stripped from lake whitefish spawning in Lake Michigan were incubated in the laboratory at temperatures similar to those on whitefish spawning grounds in Lake Michigan during December-April. Observed times from fertilization to attachment of each of 21 developmental stages were used to test a model that predicts the rate of development at daily fluctuating temperatures; the model relates rate of development for any given stage j, expressed as the reciprocal of time (Rj), to temperature (T). The generalized equation for a developmental stage is Rj = abt ct[squared]. The model was used to predict the effects of small temperature increases (caused by a hypothetical waste-heat discharge) on the rate of development and time of hatching of lake whitefish eggs.
Author: W. Waynon Johnson Publisher: ISBN: Category : Acute toxicity testing Languages : en Pages : 16
Book Description
Toxicities of four chemical forest fire retardants, Fire-Trol 100 and 931 (ammonium sulfate, or polyphosphate with an attapulgit clay thickner) and Phos-Chek 202A and 259 (diammonium phosphate with guar gum derivative thickner) were determined by static and flow-through toxicity tests for fry and fingerling coho salmon and rainbow trout; fingerling fathead minnows, bluegills, and largemouth bass; and mature scuds. In static tests, Phos-Chek formulations were more toxic than either of the Fire-Trol formulations to scuds and all life stages of fish. In salmon and trout, fry were generally more susceptible than fingerlings to all formulations; yolk-sac fry were more susceptible than swim-up friy. Toxicities of all formulations to salmon and trout were similar at 6 to 11 degress centigrade. Un-ionized ammonia is believed to be the most toxic component of thes fire retardants.
Author: William Roland Nelson
Author: William Roland Nelson
Author: Hugh A. Poston
Author: LaRue Wells
Author: D. F. Woodward
Author: 
Author: James Walter Morton
Author: United States. Bureau of Sport Fisheries and Wildlife
Author: Roy F. Heberger
Author: William H. Berlin
Author: W. Waynon Johnson