2. Limnoria . Limnorla occurred in 6 of the 19 control panels 

 and in 19 of the 26 test panels. In the test pajiels there was a slow, 

 "but more or less gradual, "build-up from the "beginning of the test, "but 

 the maximum attack, even after 8 months' exposure, did not exceed a 

 low slight rating and rated only a trace most of the time. 



A58.04 Fouling Agents 



1. Silt . Silt occurred as traces on 15 of the 19 control 

 pajiels and as traces to light deposits on 25 of the 26 test panels. 



2. InYerte"brate animal phyla . 



a. Coelenterata (hydroida ) . Hydroids occurred as traces 

 on 7 of the 19 control panels. They also occiirred as traces on the 

 first ik of the test panels submerged up to NoTem"ber 15, 19^5* 'but 

 no forms occurred thereafter. Bugula flabellata was the only form 

 identified. 



"b. Bryozoa (encrustinp; and filamentous ). Encrusting 

 Bryozoa were lacking on the control panels "but occurred on l6 test 

 panels. Tlieir occurrence on the latter resem"bled that of the hydroids 

 in that, with the exception of the first panel, they occurred regularly 

 on all panels removed "before Novem"ber 15, 19^5, but occurred subsequently 

 only on the last 2 panels in the test. They ranged from a few up 

 to 55 colonies per panel. Schizoporella unicornis was identified 

 repeatedly; Cheiloporina praelon^ca also was identified. Filamentous 

 Bryozoa were recorded on only 5 of "the test panels. 



c. Annelida (annelid worms ). Traces of serpulid ( Serpula ) 

 worms were recorded on only k test panels. 



d. Arthropoda (cr-ustaceajis ). Beilanus (barnacles) occurred 

 on only 2 control panels, where the maximum diameter was 2 mm. On 



the test panels, they occurred regularly on all panels removed from July 6 

 to November 15, 19^5^ after 8 months* su'bmergence. One panel was 

 10^ covered; one, kO^; one, 50^; and three, 100^. Strangely, however, 

 despite their abundance during this period, there were no barnacles on 

 the test panels at ajiy other time. The maximum diameter recorded was 

 15 mm in a panel su"bmerged 8 months. 



A58.05 Summary emd Conclusions 



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

 at the Todd Pacific Shipyards, Inc., at Tacoma, Washington, from September 

 15, 19^ until its discontinuance on March 19, 19^6, to determine the 

 identity and prevalence of marine borers and fouling agents at this 

 location. 



170 



