//7 - Internittent 3.0 ppm, 2 hrs. on, 2 hrs. off - no borers. 



#8 - Intermittent .5 ppm, 2 weeks on, 2 vreeks off - 20i: Teredinidae. 



In order to deter-nine the effect of the chlorination on adult teredinidae 

 two untreated wooden panels wi-ich had been submerged in the ocean for one 

 month Yirere selected, each panel shov/ing from ten to tvrelve pairs of si- 

 phons extended and active. Both panels vrere exposed to continuous chlo- 

 rination of 0,5 ppm. The siphons xuere immediately withdrawn and the en- 

 trance holes closed hy the pallets. After expoFure periods of fifteen 

 and thirty minutes, respectively, to these conditions the panels were 

 placed in flovdn^, unchlorinated sea water. In both cases the pallets 

 were withdravm and the siphons extended. At the end of twenty-four hours 

 the organisms were still alive and active, remaining so for a number of 

 succeedin)7 days.. 



Four additiona"! panels which contained an avers r^e of ten active teredi- 

 nidae were then exposed to intermittent chlorination of 3.0 ppm, 2 hours 

 on and 2 hours off. After periods of exposure varying from 2 hours to 

 5-3/U hours, all of the panels vrere removed to fresh sea vrater. Ae;ain 

 all the mature organisms had sui'vived and continued to carry on nolTnal act- 

 tivities, even survivi-nrf shipment of the panels to the laboratory at Dux- 

 bury, ITassachusetts, ^vhere they vrere placed in water 20°F, colder than 

 that to viThich they were accustomed. After one week in the Duxbury water 

 they \7eve still active, 



It is obvious that comparatively shoH exposures to the concentrations 

 of chloilne mentioned had no im:nediate effect on the organisms and also 

 did not disturb them to th.e extent that a delayed kill resulted. 



During the summer of 19^1 another series of tests vrere designed involv- 

 ing combinations of chlorination and elevated temperatures according to 

 the following schedule: 



#1 - Control - untreated sea \Tater. 



#2 - 0.2^ ppm of chlorine, continuously. 



#3 - No chlorine. Temperature of floTfing water raised to 



110°F, 30 mins. per week. 



#li - 0.25 ppm of chlorine continuously, plus raising tempera- 

 ture of ivater to llO^F. for 30 mins. per week. 



#5 - 1.00 ppm of chlorine, 1 hour in 6. 



■^■'6 - 1.00 ppm of chlorine, 1 hour in 6, plus raising temperature 



of vfater to IIQOF. for 30 mins. per vreek. 



#7 - 1.00 ppm of chlorine, 1 hour in 12. 



