commercial demand and clam abundance may limit the expansion of the soft-shell 

 clam industry in Maine. In 1976 Maine supplied 70% of the total U.S. catch 

 but that figure is expected to decrease in the future, because of the 

 increased harvest in Maryland and the general increase in development of other 

 shellfish products. 



Although "red tide" (paralytic shellfish poisoning) occurs in the coastal 

 waters of Maine it apparently has little effect on the distribution or 

 abundance of the soft-shell clam, but clams in the infected area may become 

 unfit for human consumption (see "Red Tide," this chapter) and sufficient 

 quantities of toxins may be lethal. In recent years clam harvesting has been 

 banned temporarily in infected areas. 



Management 



The State of Maine's management of clam resources is based largely on an 

 aggregate of town management plans (personal communication from P. L. Goggins, 

 Maine Department of Marine Resources, Augusta, ME; April, 1978). The state 

 legislature allows towns which have appropriated funds for shellfish 

 management to restrict clam digging to specific flats within their municipal 

 jurisdictions. Forty-seven out of the 102 coastal towns have clam ordinances, 

 and this number includes a relatively high percentage of towns having 

 substantial clam resources (personal communication from P. L. Goggins, Maine 

 Department of Marine Resources, Augusta, ME; April, 1978). 



Clam ordinances vary considerably among towns. Conservation measures include 

 the rotation of flats (i.e., digging for clams is prohibited periodically by 

 year on certain flats) to maintain quantities of clams, restriction of 

 nonresident (town) licenses, and regulation of the time of harvest. 



The State of Maine requires license fees from individuals landing more than 

 1/2 bushel of clams at one time and it restricts methods of harvest, such as 

 limiting use of hydraulic dredges to some areas. Hydraulic dredges, which are 

 much more efficient than digging by hand, could, if used extensively, cause 

 rapid depletion of stocks in Maine and excessively disturb bottom organisms 

 and sediments. On the other hand, because dredging in Maine is restricted by 

 law to specific areas along the coast, large scale commercial dredging is not 

 likely (Mathieson and De Rocher 1974) . The State may also prohibit clam 

 digging in areas where coliform bacteria counts are high or where red tide and 

 industrial pollution are a threat. 



Attempts by the State to place a size limit on clams was found to have no 

 effect on clam populations (Dow and Wallace 1961) and currently no limit is in 

 effect. The market demand for clams smaller than 2 inches is low. 



To protect soft-shell clam beds from green crab predation, experimental fences 

 have been used to exclude crabs from beds. Although this method appears to be 

 effective, it is currently cost prohibitive. 



Some towns in Maine transplant clams from flats which have high concentrations 

 of juvenile clams to flats which have low concentrations. A potential problem 

 in this practice is that if the cyst form of the "red tide" organism has been 

 ingested by transplanted clams, it will be spread to new areas. 



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