Verification of a Model for Predicting the Effect of Inconstant Temperature on Embryonic Development of Lake Whitefish (Coregonus Clupeaformis)
Verification of a Model for Predicting the Effect of Inconstant Temperature on Embryonic Development of Lake Whitefish (Coregonus Clupeaformis)

Author: William H. Berlin

Publisher:

Published: 1977

Total Pages: 12

ISBN-13:

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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.

Ecological Effects of Dredging and Dredge Spoil Disposal
Ecological Effects of Dredging and Dredge Spoil Disposal

Author: James Walter Morton

Publisher:

Published: 1977

Total Pages: 44

ISBN-13:

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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.

Abundance, Composition, and Distribution of Crustacean Zooplankton in Relation to Hypolimnetic Oxygen Depletion in West-central Lake Erie
Abundance, Composition, and Distribution of Crustacean Zooplankton in Relation to Hypolimnetic Oxygen Depletion in West-central Lake Erie

Author: Roy F. Heberger

Publisher:

Published: 1977

Total Pages: 24

ISBN-13:

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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.