FISHERY BULLETIN: VOL. 80, NO. 4 



Russia; and Snow and Marsden (1974) at Brandy 

 Cove, St. Andrews, New Brunswick, Canada. 



Materials and Methods 



All sandworms were collected in the vicinity of 

 a small intertidal mud flat at Wiscasset, Maine, 

 closed to commercial digging. Within this area, a 

 section running parallel to the low-water mark 

 and measuring 91 m X 24 m was used for experi- 

 mental purposes. Differences in tidal height be- 

 tween the upper and lower extremities of this 

 experimental area were about 22 cm. Monthly, 

 three 1 m 2 sample plots were randomly chosen 

 and dug within the experimental site. The sam- 

 pling device consisted of a 1 m 2 frame with deep 

 walls (45 cm) that could be pushed into the mud 

 to prevent escape. Within each plot, the surface 

 ooze was removed with a dustpan to a depth of 2-3 

 cm and deposited within a square framed recep- 

 tacle constructed of 1 mm mesh fiberglass screen. 

 The receptacle was then partially immersed in 

 the river and carefully agitated to remove sedi- 

 ment. The remaining debris and worms were 

 poured into a plastic container and transported 

 to the laboratory. Small portions of debris, to- 

 gether with seawater, were deposited in dissect- 

 ing trays and dispersed with a needle probe. The 

 contents were thoroughly searched and all small 

 sandworms, swimming or hiding among the 

 debris, were removed with forceps. Clumps of 

 deeper and firmer mud were removed from the 

 sampling device in the field to the maximum 

 depth of burrowing activity (about 30 cm) and 

 carefully broken by hand to remove the larger 

 worms intact. These worms were also trans- 

 ported to the laboratory in plastic buckets. 



All sandworms were acclimated to high salin- 

 ity water (about 32% ) at the laboratory prior to 

 immersion in anesthetic (7.5% MgCb). Lengths 

 were obtained using a V-shaped measuring 

 trough containing ample anesthetic to cover the 

 worms. Coelomic fluid was withdrawn with the 

 aid of capillary pipettes, and sex was determined 

 by microscopic examination of the contents. Egg 

 diameters were measured with an ocular mi- 

 crometer and without a cover slip. Usually 10 

 eggs were measured from each worm. The rela- 

 tionship of sandworm length to numbers of eggs 

 laid was corrected for transformation bias fol- 

 lowing the methodology of Bradu and Mundlak 

 (1970). 



Worms used in the study to determine the per- 

 cent of mature males and females and immature 



females in each length increment were obtained 

 during February (prior to spawning) from pooled 

 samples dug independently of the regular 

 monthly sample. The distinction between ma- 

 ture and immature females was made after 

 examining eggs in the coelomic fluid; large eggs 

 from mature worms would be spawned in April 

 or May, and small eggs would be spawned ap- 

 proximately 1 yr later. We were unable to make a 

 distinction between mature and immature 

 males. 



Sandworms designated "nonspawners" include 

 worms of all sizes that have not spawned and 

 whose coelomic contents present no clue about 

 sexuality. "Spent" worms include both males and 

 females that have spawned and are deteriorating 

 and approaching death. 



Female sandworms used for egg counts were 

 anesthetized, measured, and preserved. The 

 worms were then split lengthwise and washed 

 thoroughly to remove as many eggs as possible. 

 Next, the body was chopped into 1 cm pieces, im- 

 mersed in seawater, and stirred magnetically. 

 After three or four changes of water, most eggs 

 were dislodged. Egg samples were diluted in 

 0.1-2.7 1 seawater, depending upon size of the 

 worm and numbers of eggs present. Two 1 ml ali- 

 quots were withdrawn from this mixture during 

 agitation, placed on Sedgwick-Rafter 5 counting 

 cells, and the number of eggs counted under the 

 10X objective. The mean value was then multi- 



5 Reference to trade names does not imply endorsement by 

 the National Marine Fisheries Service, NOAA. 



cc 



3 



< 

 CC 



CL 



TEMP (SURFACE) 



& & TEMP(BOTTOM> 



• • SALINITY (SURFACE] 



□ □ SALINITY (BOTTOM ) 



30 

 28 



26 ° 



>- 



24 



222 



20 



18 



16 



I I I I I I I I I I I 



NDjJFMAMJJASO 

 1966 I 1967 



Figure 1.— Summary of temperature and salinity data col- 

 lected from the Sheepscot River near the Wiscasset closed area 

 between November 1966 and October 1967. 



736 



