A15.05 Marine' Borera 



Not the slightest trace of either Teredlnldae or Limnoria was 

 recorded in the test hoards operated at the Philadelphia Naval Shipyard 

 in either the Schuylkill or Delaware Rivers. Because analyses of the 

 vater at monthly intervals over the nearly three-year period covered 

 hy the test show that it is entirely fresh, neither of these groups of 

 marine "borers could possihly occur. 



A13 . Ok Fouling Agents 



1. Silt . Silt occurred on all the control and test panels of 

 the test hoards at hoth locations, the deposits ranging from traces to 

 moderate, or rarely heavy, and mostly oily. 



2. Algae . Traces of green and hrown algae were recorded on 

 a single one of the test panels of Test Board No. 2 in the Delaware 

 Eiver, which had been submerged for 8 months. 



5. Invertebrate anlmai phyla . 



a. Coelenterata (hydroida ). A trace of hydroids was 

 ■recorded on a single control panel and on a single test panel of Test 

 ; Board No. 1, operated in the Schuylkill River. A light growth was 

 recorded on a single control panel and traces on 2 test panels of 

 Test Board No. 2, operated in the Delaware Eiver. 



AI5.O5 SutTmifl.ry and Conclusions 



1. Installation . A test board of the panel type was operated 

 at the U. S. Naval Shipyard at Philadelphia, Pennsylvania, from July 

 17, 1941+ until March 17, 19*1-7, to determine the identity and prevalence 

 of marine borers and fouling agents at this location. 



2. Test Results . 



a. Borers. Not the slightest trace of either Teredlnldae 

 or Limnoria was recorded in the teat boards operated in either the 

 Schuylkill or Delaware Rivers. Since the water at both these locations 

 is entirely fresh, neither of these groups of marine borers could 

 possibly occur. 



b. Fouling Organisms . The freshness of the water at both 

 these locations almost completely inhibited the growth of other marine 

 organisms. Only traces of hydroids were recorded on 2 or 5 of the 

 panels at each location, and algae occurred only as a trace on a 



single panel of the board in the Delaware River. Deposits of silt, usually 

 oily, occurred more or less abundantly on all control and teat panela 

 at both locations. 



As there was nothing of value to be learned by further operation 

 of this test board, its teimination was requested. 



63 



