Acrolein, Dalapon, Dichlobenil, Diquat, and Endothal
Acrolein, Dalapon, Dichlobenil, Diquat, and Endothal

Author: Leroy C. Folmar

Publisher:

Published: 1977

Total Pages: 24

ISBN-13:

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Toxicity tables for the herbicides acrolein, dalapon, dichlobenil, diquat, and endothal list the test organisms, types of tests, experimental conditions, and test results. Each table is followed by a list of references. The materials provide a useful source of toxicity data on these herbicides to researchers, regulatory agencies, and manufacturers.

Biology of the Redtail Surfperch (Amphistichus Rhodoterus) from the Central Oregon Coast
Biology of the Redtail Surfperch (Amphistichus Rhodoterus) from the Central Oregon Coast

Author: Donald E. Bennett

Publisher:

Published: 1977

Total Pages: 32

ISBN-13:

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Data on certain aspects of the life history of the redtail surfperch were collected along the central coast of Oregon, from April 1967 through April 1969. Annulus formation occured during February through June, usually earlier in young than in older fish. Mating occurred from late December to early January, and the young were born from July through September. The number of embryos per female ranged from 1 to 39 (mean 13.3) and increased linearly with the length and weight of the females. Food of the fish from the surf zone included crustaceans (by far the most important group in both frequency of occurrence and total volume) and (in order of decreasing importance) fishes, mollusks, and polychaetes. Parasites of the redtail surfperch were immature nematodes (Anisakinae) ; the digenetic trematode Genitocotyle acirra; the monogenetic trematode, Diclidophora sp.; and the copepods, Caligus sp., Clavella sp., and Argulus catostomi.

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.

Neuroendocrine Mediation of Photoperiod and Other Environmental Influences on Physiological Responses of Salmonids
Neuroendocrine Mediation of Photoperiod and Other Environmental Influences on Physiological Responses of Salmonids

Author: Hugh A. Poston

Publisher:

Published: 1978

Total Pages: 20

ISBN-13:

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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.