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Thesis (M.S.)—University of Nebraska—Lincoln, 1971. Department of Zoology.


Copyright 1971, the author. Used by permission.


This thesis defines the relationship between growth and reproduction and temperature and salinity for Styela sp. in the Marina Del Rey, Venice, California, a specific point in geographical range of this species.

Styela sp. exhibits an annual reproductive cycle.The breeding period extends from late February into November.From December through January phagocytosis is observed to occur in the ovaries to unshed rip ova, in response to climatic conditions.

Styela sp. grows at a steady rate throughout the course of the year regardless of climatic conditions until the animal reaches a size of 8.5 cm, at which size during winter months, growth slows.There are indications that above 10 cm, growth is progressively retarded.Animals grew at a rate of 0.6 cm/28 days during the winter.

Styela sp. reaches sexual maturity at a size of 7 to 9 cm, at which time the rate of growth is slowed during winter and an increase in the number of ripe oocytes is observed.With age, there is an accumulation of excretory products beneath the atrial epithelium around the gonad tissue.

Advisor: Carl W. Gugler