control panels, and maximum leiagths of kO, 38 > Buad. k2 mm were recorded 

 on the test panels at these locations in d^, S, and 9 months, respectively. 

 At Shipbuilding Ways Wo. 8, 2 of the test pamels were 60^ to 100^ covered, 

 and at the Naval Ammunition Depot Pier, K of the test panels were 25?^ 

 to 100^ covered. 



e. Chordata (tunlcates ). A few colonies of tunicates 

 ( BotryllTis schlosseri ) occurred on a single test panel at Finger Pier 

 Wo. 21. 



kkO . 05 Summary sjad Conclusions 



1. Installation . Three test toards of the panel type installed 

 at different locations at the Mare Island Naval Shipyard at Vallejo, 

 California, on June 20 and 21, 19kh, are still "being operated. The 

 results of these tests have been summarized to the end of ISl^l. 



2. Test Results . 



a. Borers. Teredlnidae were active at all locations 

 throvighout most of the period covered by the tests, the breeding season 

 at each place apparently extending from the middle of Jfeiy through 

 October. At Shipbuilding Ways Wo. 8, the attack rated very heavy in 

 19i|-5, moderate in 19^6, and very heavy in 19^7. At Finger Pier Wo. 21, 

 there was no attack in 19^5* only a moderate one in 19^6, but a very 

 heavy attack in 19^7. At the Naval Ammunition Depot Pier, the attack 

 rated very heavy in IS'kh and 19^5 » moderate in V^G, and very heavy 



in 19^7. No evidence of Limnoria occurred in either the control or 

 test panels at any of the three locations. 



b. Fouling Organisms . Silt, algae, and invertebrate 

 animals belonging to 5 phyla contributed to fouling of the pemels. 

 The latter comprised hydroids, encrusting and filamentotis Bryozoa, 

 barnacles a n d araphipods, mussels, eind tunicates. Of these organisms, 

 hydroids and barnacles occurred with greatest frequency, with the latter 

 in unusual abundance; mussels occurred with considerable frequency; 

 encrusting Bryozoa occurred with less frequency; and the occurrence of 

 the others, as well as the algae, was purely sporadic or occasional. 



5. Recent Addenda . The Teredlnidae attack was moderate in ISkQ 

 and slight in 19^9 at Shipbuilding Ways Wo. 8. There was no evidence 

 of Llmnoria either year at this location. At Finger Pier Wo. 21, 

 a medium heavy attack of Teredlnidae occurred in 1948, and a moderate 

 attack occurred in 19^9. Again, no Llmnoria occurred either year at this 

 location. Examination of panels from the test board at the Naval Ammunition 

 Depot Pier revealed a moderate Teredlnidae attack in 19^8 and a medium 

 heavy onslaught the following year. Wo Llmnoria at all made their 

 appearance either year on this test board. 



181 



