15 of the 59 control panels and on 55 of the same nuaiber of test panels. 

 Ten panels of the control series were from 25^ to 75^ coTered, and 22 

 fJanels of the test series were from 25^ to 100^ covered. A maximum 

 diameter of 7 ram was recorded on a control pajxel and 22 mm on a 

 test panel, after they had "been submerged for k months.' 



e. Molluflca (nonhoring mollusks ). A solitary specimen of 

 Anomla (jinsle-shells), with a diameter of 6 ram after k months' submergence* 

 occurred on a single test peinel. Single specimens of t^ilus (mussels ^ 

 occurred on two of the test panels, one attaining a length of 12 mm 



after k months' suhmergence. 



f . Chorda ta (tunicates ). Tunica tes occurred on one control 

 panel and on 2 test panels. All were identified as Botryllus sohlosseri . 



A55«05 Summary and Conclusions 



1. Installation . A test board of the panel type installed July 

 18, 19'<-^, at the U. S. Naval Magazine and' Net Depot at Indlaui Island, 

 Hadlock, Washington, to determine the identity and prevalence of mwin© 

 "borers and, fouling organisms, is still "being operated. The resulta ©f 

 this test have "been suimnarized to the end of 19^7 • 



2. Test Eesults . 



a. Borers . Teredinidae were very active throughout the period 

 of the test, the "breeding season apparently lasting from the middle of 

 March through Decemher. The attack rated very heavy in 19^5 and appeared 

 to "be eq.ually heavy in 19^6 eind 19^7* although the period of suhmergence 

 was reduced from 8 to 4 months. Llmnoria also were active throughout the 

 period of the test, "but the attack never exceeded a low slight rating 

 in any one year. 



"b. Fouling Organisms . Silt, algae, emd inverte"brate animals 

 belonging to 6 phyla contributed to fouling of the panels. The latter 

 con5)rised hydroids and Metridium , encrusting and filamentous Bryozoa, 

 serpulid worms, beirnacles. Jingle-shells emd mussels, and tunicates. Of 

 these organiams, baxnacles occurred with by far the greatest frequency 

 and abundance; hydroids, filamentous Bryozoa, emd encrusting Bryozoa with 

 regressively less frequency; while the occurrence of the others, as 

 well as the algae, was merely sporadic or occasional. 



5. Recent Addenda . There was a heavy attack by Teredinidae at this 

 station in both 19li-8 and 1949. The Limnoria attack rated slight both 

 years. 



157 



