. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. REPRODUCTIVE CYCLES OF M. EDULIS 303 24 o ~ 20 LU tr i i6 o: LU £ 12 LU I— S 8 ^ 4 0. J J A SOND 1976 J FMAMJ J A SO ND 1977 JFMAMJ JASOND 1978 FIGURE 3. Seasonal variation in water temperature (°C) at Stony Brook (• — necock (O - - O). Each point represents a single measurement of water temperature. JFMAMJJASO 1979 >) and Shin- September to October. Gametogenesis was initiated again in November and con- tinued through the winter, with a peak GVF of approximately in April/May. In contrast, the Shinnecock population ap
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. REPRODUCTIVE CYCLES OF M. EDULIS 303 24 o ~ 20 LU tr i i6 o: LU £ 12 LU I— S 8 ^ 4 0. J J A SOND 1976 J FMAMJ J A SO ND 1977 JFMAMJ JASOND 1978 FIGURE 3. Seasonal variation in water temperature (°C) at Stony Brook (• — necock (O - - O). Each point represents a single measurement of water temperature. JFMAMJJASO 1979 >) and Shin- September to October. Gametogenesis was initiated again in November and con- tinued through the winter, with a peak GVF of approximately in April/May. In contrast, the Shinnecock population appears to have a less regular cycle, with large between-year variation in both the timing of various phases of the ga- metogenic cycle and the annual maximum reproductive condition attained (Fig. 4). The maximum GVF varied from about GVF (1977) to GVF (1978), generally lower than at Stony Brook. In each year, maximum GVF occurred be- tween July and October, or about three months later than at Stony Brook. Shin- necock animals exhibited a minimum GVF between March and May of approxi- mately to compared to about a GVF in September and October for Stony Brook mussels. The gradual decline in GVF during the autumn and winter in the Shinnecock mussels was probably not associated with the liberation of ga- metes by spawning, but rather due to their reabsorbtion by phagocytosis. Evidence in support of this was an increased number of haemocytes in the interfollicular tissue. The post-spawning quiescent period was maintained until about May in the Shinnecock mussel, which is considerably longer than in the Stony Brook popu- lation. A more subtle difference between the two populations of Mytilus edulis was the degree of synchrony of maximum gametogenic condition among individuals within each population. In general, the variance in GVF estimated from the 12 mussels from each sampling period was greater in the Shinnecock population (Wilcoxon two sample test, P
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
