ABOUT LOBSTERS 53 



laths. Experimental traps fished in the Stonington area in 

 1951 confirmed this observation. 



In closely related species, it has been shown that no one 

 of the following: water, temperature, salinity, hydrogen ion 

 content, dissolved oxygen, pollution, and turbidity, is the de- 

 termining factor in increasing borer population with its con- 

 sequent increased timber destruction. It has been suggested 

 that a favorable combination of some or all of these factors 

 is what determines an increase in borer population and 

 activity. 



Some information is available now on the borer from 

 investigations made elsewhere as well as observations made 

 by the Department of Sea and Shore Fisheries in Maine. It 

 appears that the borer, at the end of its early swimming 

 stages, attaches itself by means of its threadlike filaments to 

 wood. The spawning activity of these organisms is greatest 

 during cold weather, though spawning seems to be influ- 

 enced by age, and some young are in the water during all 

 seasons of the year. As the borer's shell forms, it works its 

 way beneath the wood surface, where it establishes its pro- 

 tective burrow. Once the borer has established itself within 

 the burrow, it grows rapidly and enlarges its home by rasp- 

 ing away the wood with the hind end of its shell. It may 

 seem surprising that a mollusk as relatively large as a mature 

 borer could have gained entrance to its burrow through a 

 hole as small as that appearing on the wood surface. 



Whether or not the borer gains any nourishment from 

 the wood is not entirely clear. Closely related species some 

 years ago were believed to depend entirely on siphonable 

 water-borne food for their nourishment, but more recent 

 studies indicate the likelihood that a portion of their food is 

 derived from the wood they grind up in establishing and en- 

 larging their burrows. 



Preservatives. A survey of the literature concerning 

 prevention of damage to lobster pots by marine borers led 

 to three possible methods of attack; namely, the sheathing 



