SEA MUSSEL MYTILUS EDULIS. 24I 



which he thought would be ready for the 1917 market. With his services as a guide, a 

 series of dredgings was made the entire length of the bed, with the result that not a single 

 large mussel was taken. A heavy set of young mussels from three-eighths to three-fourths 

 of an inch long, however, was found to cover the entire territory. The explanation 

 for the complete disappearance of the old bed was that during the heavy storms of the 

 winter the tidal currents and wave action had been strong enough to strip the shellfish 

 from the bottom and carry them to distant points. 



Other causes which account for the damage or destruction of beds are freshets, 

 shifting sand and ice, freezing of mussels exposed at low tide, depredations of starfish, 

 drills, and other enemies, and suffocation from the mussels' own excrement. It is well 

 known that mussel beds collect great quantities of mud, but few persons have realized 

 that this mud, in large part, represents the excrement discharged by the mussels them- 

 selves. To determine roughly the quantity of waste matter which is thrown off by 

 mussels daily, twenty-five 3-inch mussels were placed in a clean trough of slowly running 

 sea water where the body discharges could be collected with a pipette from time to time. 

 During a period of 72 hours the excrement given off measured 3,065 c. mm. Its com- 

 position, as revealed by the microscope, was diatom shells and detritus. This means 

 that where mussels of this size lie no thicker than 500 to the square yard they discharge 

 not less than 20 cc. of feces daily, and if this rate is maintained throughout the year 

 the result would be an annual deposit of 7,000 cc, or about 1 peck, of the muddy matter 

 per square yard. Viallanes (1892), making similar observations, states that in propor- 

 tion to the numbers covering the same area of ground the mussel will deposit 3 times 

 as much material as a Portuguese oyster and 18 times as much as a French oyster. 

 Knowledge of this fact makes it easy to understand how a mussel bed, in a few years 

 time, can build up a thick layer of mud and be destroyed by its own waste products. 



Under natural conditions a uniform supply of mussels can not be depended upon, 

 for, as past history has shown, there are years when they are exceedingly abundant 

 and others when they are very scarce. The problem of maintaining a large and con- 

 stant supply can be easily solved, however, by transplanting the young shellfish from 

 exposed natural beds to favorable grounds in protected bays and estuaries as is now 

 being practiced in Cold Spring Harbor. Minimum waste will occur where cultivated beds 

 are completely cleaned up when ready for market and promptly planted again with 

 seed mussels. The mortality rate will be low on beds that are permitted to stand not 

 more than three years. Hard bottom is the most convenient ground on which to grow 

 and handle a crop of mussels, but the shellfish will thrive equally well on mud bottoms 

 which are unfit for oyster culture. The chief objection to raising mussels on mud is 

 that it increases the cost of gathering and preparing them for market. 



EFFORTS TO DEVELOP A MUSSEL INDUSTRY IN THE UNITED STATES. 



Recognizing the importance of the extensive sea-mussel beds on the north Atlantic 

 coast as a valuable source of food supply and the fact that as a nation we are failing to 

 utilize them through ignorance or unreasonable prejudice, the Bureau of Fisheries 

 undertook a limited publicity campaign in the spring of 19 14 to acquaint the people 

 of Boston and vicinity with the food qualities of this little-known shellfish. A 5-page 

 pamphlet for public distribution was issued March 24, 1914, under the title "Sea 



