THE ANNUAL REPRODUCTIVE AND NUTRITIONAL CYCLES IN TWO WESTERN SEA URCHINS

作者：John Cook Bennett, Arthur C. Giese · 发表于：Biological Bulletin · 年份：1955 · DOI：10.2307/1538723 · 被引用次数：73 · 研究领域：Marine and coastal plant biology、Ocean Acidification Effects and Responses、Coastal and Marine Management

1. The degree of gonadal development in the purple sea urchin, Strongylocentrotus purpuratus, was measured by taking the gonad index, or ratio of volume of gonad to wet weight of urchin, every two weeks for a year (1953-54) in samples of 20 urchins obtained from each of two localities, Pescadero Point on the Monterey Peninsula, and Yankee Point, 10 miles south.2. For S. purpuratus from both places, the average gonad index rose during the fall to a peak twice as high as that reached the previous year, and this peak was maintained at a fairly constant level from January through May.3. Climatic factors, rather than ecological, are therefore thought to have the greater effect upon gonad growth. A clear-cut correlation was not established for any factor, but ocean temperature is known to have been higher during the winter of 1953-54 than in the previous year.4. Determination of the gonad index for monthly samples of 10 specimens of the large western sea urchin, S. franciscanus, taken from below the tide pools of the Hopkins Marine Station, indicated a single reproductive cycle, but a much shorter breeding season, the peak of which was reached later than that of S. purpuratus.5. Though males were found to have fertile gametes for a greater part of the year than females, no significant difference was found in the reproductive cycles of male and female urchins in either species, as measured by gonad index.6. The great growth of gonads was not correlated with an increase in NPN (non-p...