. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 166 AAGE M0LLER CHRISTENSEN AND JOHN J. McDERMOTT of July, less than 5% of the collected crabs were males, and by early September not a single 1955 male could be found. Also beginning on about June 20th, the incidence of infestation (Oysters in- fested), which had remained at a constant level, around 58%, since February, began to fall quickly. It continued to do so until the number of males occurring in the samples became insignificant. Then the incidence again became constant, but now at the lower level of about 35%, or jus
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 166 AAGE M0LLER CHRISTENSEN AND JOHN J. McDERMOTT of July, less than 5% of the collected crabs were males, and by early September not a single 1955 male could be found. Also beginning on about June 20th, the incidence of infestation (Oysters in- fested), which had remained at a constant level, around 58%, since February, began to fall quickly. It continued to do so until the number of males occurring in the samples became insignificant. Then the incidence again became constant, but now at the lower level of about 35%, or just about the level where it would have been on June 20th if only the females had been considered. A fourth curve (Double infestations) in Figure 5 shows that within the same period of time, beginning towards the end of June, a notable number of double infestations began to occur. Those shown for the winter months were due to LU o IOO 90 80 70 SO 50 tr HI Q- 4O 30 2O 10 OYSTERS INFESTED FEMALE CRABS HARD CRABS,J & $ DOUBLE INFESTATIONS OVIGEROUS CRABS. M J 1956 0 FIGURE 5. The curves show: 1. Incidence of infestation and double infestations of the 1955 year-class of oysters on the Bay Shore Channel Bed, and 2. Sex ratio (as per cent females) and development (in part) of the 1955 year-class of P. ostrcnin inhabiting these oysters, in the period from December 14, 1955 to October 9, 1956. Data on double infestations include results obtained from extra sample of 334 infested spat collected on July llth, 16 of which were double infested. original multi-infestations by invasive stage crabs, but those which occurred during the summer could only be due to new invasions by hard stage crabs. An examina- tion of this summer material showed that each double infestation consisted of one crab of each sex. Such pairs were also found in collections made on other grounds during this period of the year. In a few cases two or three males had invaded the same oyster containing a female. It was s
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
