Table 9.— A comparison of the diggers' time estimates with the actual time recorded. 













Diggers 



Actual 









No. 



diggers 





estimate 



recorded 



Error 



Date 



Area 



checked 



SorB 



(h) 



(h) 



(%) 



4/03/74 



Cod Cove-Wiscasset 





19 



B 



48.22 



48.30 



-0.17 



4/12/74 



Hilton Cove-Wiscasset 





15 



B 



46.33 



45.08 



+ 2.77 



4/14/74 



Yacht Club-Wiscasset 





6 



B 



18.45 



18.42 



+ 0.16 



5/13/74 



Back R.-Boothbav 





6 



S 



8.33 



8.33 







8/17/77 



Ravs Pt. -Harrington 





6 



S 



6.58 



7.65 



-13.99 



8/18/77 



Hog Bay-Franklin 





8 



B 



18.50 



16.50 



+ 12.12 



8/23/77 



Skilling R. -Hancock 





12 



B 



30.25 



29.25 



+ 3.42 



10/12/77 



Jones Cove-W. Gouldsboro 





6 



78 



S 



9.12 



9.03 

 182.56 



+ 1.00 





185.78 



+ 1.77 



The literature contains many references to the commercially 

 acceptable size of bloodworms and sandworms. However, few of 

 these measurements are comparable because the worms were mea- 

 sured by various means. Sandrof ( 1946) reported the average length 

 of bloodworms at 6-8 in (15.2-20.3 cm) natural length. Ganaros 

 (footnote 4) stated that the minimum size for bloodworms was 

 18-20 cm. Dow (footnote 18) reported that Ganaros' measure- 

 ments were recorded from worms placed next to a ruler. Tax- 

 iarchis 3: reported that the minimum size for bloodworms was 16 

 cm. He first anesthetized his worms in 7.5% MgCK and then mea- 

 sured them next to a ruler. MacPhail (1954) and Pettibone (1963) 

 reported that the minimum marketable size was 6 in (15.2 cm). 

 Klawe and Dickie (1957) reported that bloodworm diggers in Nova 

 Scotia ordinarily harvest worms that are more than 20 cm (7.9 in) 

 measured in 7.5% MgCl 2 . 



Sandrof (1946) reported that the normal size range for sand- 

 worms was 10-18 in (25.4^4-5.7 cm) natural length. Ganaros (foot- 

 note 4) reported the minimum commercial size of sandworms at 

 between 21 and 22 cm. Following discussions with various 

 Boothbay, Maine, worm dealers, Taxiarchis" concluded that the 

 minimum commercial size for sandworms was 8 in (20.3 cm) natu- 

 ral length. MacPhail (1954) reported that the minimum marketable 

 size for sandworms was 6-7 in (15.2-17.8 cm) and Pettibone 

 (1963) stated that a sandworm length of 20 cm was required to be of 

 commercial importance. 



Length and Weight Frequency Samples 



Monthly sexed length frequency data recorded for the 

 commercial bloodworm and sandworm catches sampled between 

 1973 and 1976 are shown in Figures 7 and 8, respectively. 



In Figure 7, the complete lack of maturing spawners during April 

 1975 may be attributed to the small sample size (/V=44) and the 

 fact that the random samples were only collected in the eastern por- 

 tion of the state where bloodworm spawners were lacking from 

 commercial samples. 



The commercial sandworm samples for 1974, 1975, and 1976 

 (Fig. 8j show that during August and September individual female 

 sandworms contained eggs of either one of two size ranges. This 

 happens because spawning occurs annually in sandworm popula- 

 tions but the period of egg development in the coelom is longer than 

 12 mo. Therefore, worms containing larger eggs will spawn the fol- 

 lowing March-May, whereas those containing small eggs will 



32 Taxiarchis. L. N. 1954. Field notes on marine worms. Dep. Sea Shore Fish.. 

 Augusta, 36 p. 



33 Taxiarchis. L. N. 1953. Survey of the littoral zone of York County. Maine with 

 respect to commercial productivity. Dep. Sea Shore Fish. Gen. Bull. 2. 13 p. 



spawn a year after that. Two general egg sizes have been recorded 

 in the Wiscasset sandworm population between October-Novem- 

 ber and April-May (Creaser and Clifford footnote 11). Data pre- 

 sented by Brafield and Chapman (1967) suggest that two egg sizes 

 may be present between September and April in the Thames estuary 

 (Southend, England) and Snow (1972) reported the same phenome- 

 non between September and June for sandworms collected at 

 Brandy Cove, St. Andrews, New Brunswick. 



Bloodworm and sandworm sexed length frequency data for 6 mo 

 (April-September) combined sampling data are presented in Fig- 

 ures 9 and 10, respectively. 



Weight frequency data from combined monthly samplings of the 

 commercial bloodworm and sandworm catches collected during 

 the period April-September (1974-76) are presented in Figures 1 1 

 and 12. respectively. 



Probability Sampling Expansions and 

 Ratios Estimates 



Probability sampling expansions of catch and effort and ratios of 

 two variables estimates (catch/unit effort) are presented by month 

 and 6-mo sampling periods for bloodworms and sandworms in 

 Tables 12 and 13, respectively. 



The importance of these probability sampling expansions is con- 

 siderable. Although estimates of total catch in numbers are already 

 recorded in Maine Landings, estimates of some of the other param- 

 eters are either nonexistent (total number of digger tides dug. total 

 number of digger hours dug) or they are reported in U.S. Depart- 

 ment of Commerce (1946-80) in gross error (total catch in pounds). 

 It is evident from the results presented in Tables 12 and 13 that the 

 standard errors about the mean monthly probability sampling 

 expansions are greater than those reported for the 6-mo expansions. 

 Standard errors reported for the 6 mo combined data are 

 19.7-26.2% of the mean for bloodworm expansions and 

 19.2-31.9% of the mean for sandworm expansions. Although 

 greater accuracy (smaller standard errors) of the expansions could 

 be obtained by randomly selecting more than six daylight low tides 

 per month, this could not be accomplished because of time and 

 manpower limitations. 



Based upon the results of the four 6-mo ratio estimates for blood- 

 worm and sandworm catch in numbers/digger hour, it cannot be 

 conclusively stated that bloodworm and sandworm abundance 

 changed significantly between 1973 and 1976. The only indication 

 of a decline in abundance of bloodworms occurred during 1976 

 when the catch in numbers/digger hour was significantly different 

 (at ± 1.96 SE or 95% confidence levels) from the same recorded 

 during 1974 and 1975. However, there was no significant differ- 

 ence between the 1973 and 1976 bloodworm data for catch in 

 numbers/digger hour at 95 % confidence levels. 



