In 1973 MDMR set regulations requiring the use of a minimum shrimp trawl mesh 

 size of 1.5 inches (38 mm). The regulation was revised in 1975 to 1.75 

 inches (45 mm) so that smaller and younger (under 3 years) shrimp would not be 

 caught. This regulation has had little effect on the catch composition of 

 Maine landings during the first few years of implementation (personal 

 communication from D. F. Schick, Maine Department of Marine Resources, Augusta 

 ME; April, 1978). 



The correlation between fishing effort and stock size has been found to be 

 more significant than that between temperature and stock size, and it has been 

 suggested that more severely regulated shrimp fisheries (i.e., closed seasons 

 and/or quotas) cannot substantially increase abundance before the mid-1980s, 

 and then only if temperatures are favorably low during the recovery period 

 (Clark and Anthony 1977). Warm seawater temperatures are recognized as being 

 detrimental to shrimp populations; however, the effect of temperature is 

 obscured by the dramatic increase in fishing effort (60%) in recent years 

 (Anthony and Clark 1978). The Northern Shrimp Scientific Committee (Atlantic 

 States Marine Fisheries 1977) concludes in their report for 1977 that the 

 increased fishing effort over the last 5 to 10 years has been a major factor 

 in reducing the stock size, and that the population will not be able to 

 recover without continued severe restriction of the fishery. 



MARINE WORMS 



This section describes the natural history and other aspects of the bloodworm 

 and the sandworm in Maine. Because management and marketing of both these 

 species are the same or similar, the subsections on "Importance to Humanity" 

 and "Management" review the worm industry as a whole rather than by species. 



Bloodworm ( Glycera dibranchiata ) 



The bloodworm is a polychaete that burrows in unconsolidated sediments largely 

 in the intertidal zone. From within the burrow the worm feeds on detritus and 

 small invertebrates. It generally migrates only locally within the substrate 

 but at certain times of the year bloodworms have been found in the water 

 column (Dean 1978b; and Graham and Creaser 1978). This polychaete may reach a 

 length of 16 inches (400 mm) and have up to 300 segments (Pettibone 1963). 

 The bloodworm is one of the two species that form the basis of the commercial 

 marine bait worm industry centered in coastal Maine. 



Distribution and abundance . The bloodworm range extends from the Gulf of 

 St. Lawrence to the Gulf of Mexico and from central California to Mexico. The 

 species has been found at all levels of the intertidal zone and to a depth of 

 1300 feet (400 m) . 



The most abundant populations in Maine are generally found near the low water 

 mark and may reach densities up to 17.2 worms/m (personal communication from 

 E. P. Creaser, Maine Department of Marine Resources, Augusta, ME; April, 

 1978). The worm usually inhabits the top 10 inches (25 cm) of the sediment 

 (Klawe and Dickie 1957). 



Commercial quantities are found only in Maine, New Hampshire, and 

 Massachusetts. Atlas map 4 depicts commercially important worm flats in 

 Maine. 



12-24 



