Table 6. --Number and percentage of tagged horseshoe crabs recovered 

 1952 through 1955 



Table 7. --Mean carapace width of adult male and female horseshoe crabs 

 collected in Plum Island Sound, Mass., 1952 through 1954 



DISCUSSION 



Horseshoe crabs were encountered in 

 Plum Island Sound every month of the year ex- 

 cept January and February (table 2) . As no dredg- 

 ing was done during these months, it is possible 

 that some may have been present in the subtidal 

 zone . Dredgings made during the month of 

 March indicated that some may be active at this 

 time. 



Although crabs were present in channels 

 of the sound all or nearly all year, they did not 



appear on the clam flats until April . Even at 

 this time their mumbers were very low and 

 pits made by the crabs were not in evidence . 

 In May there was an obvious and abrupt increase, 

 both in the numbers of crabs that could be picked 

 up, and in the numbers of pits on the flats . The 

 numbers of crabs present during the following 

 months increased even more abruptly, and 

 reached a peak during July and August. The total 

 numbers collected per month (1,442 and 1,049) 

 and the average number per collection (75.9 and 

 74.9) were highest for these 2 months. 



