A21.05 Marine Borers 



.■^ 1. Teredinldae . Teredlnldae , including Baiikla gouldi. Teredo 

 navalf 3, T. ( Lyrodus ) sp., T. ( Pslloteredo ) sp., and T. sp., were very 

 actlvt thro^:lghout the period of the test. The "borers were so 

 destrv "<tive that It was requested on KoTember 6, 19^5* that the panels 

 he rem ved and a new series installed in which the period of suhmergence 

 was to be reduced to k months instead of the 8-month hasis preYiously 

 eniplcyri This chinge was made on December 5* 



Teredinicl ? occurred in 52 of the ll-2 control pemels, the majcimum 

 breeding season apparently covering the period frcan February 10 to 

 January 10, although it was shorter in some years. In these panels, the 

 specimens ranged from minute pits or embryonic specimens to forms up 

 to 57 mm in length. They occurred in 51 of the 56 test panels, with 

 panels becoming filled or riddled in as short periods as 5 and h months. 

 A maximum length of 525 mm was recorded on 5 panels which had been 

 submerged for k months. The attack rated heavy each year. 



2. Limnoria. Limnoria showed more or less activity beginning 

 with 19i)-5, but no forms occurred in the control panels prior to April 

 10, and they occurred only in small numbers in these panels subsequently. 

 Moreover^ no forms occurred in the test pajiels prior to June 11. While 

 it was impossible to make an accurate count of the number of tunnels 

 late in 19^5, because of the severe riddling or destruction of the panels 

 by Teredinldae , it appears that the Limnoria attack never rated more 

 than moderate that year, only low in the slight rating in 19^6, 

 and merely a trace in 19^7. 



5» Sphaeroma . A trace of Sphaeroma occurred on 5 test 

 panels which were removed in 19^5 » after having been submerged for 8 

 months. One, 2, and 5 specimens, respectively, were recorded on these 

 5 panels. 



k. Pholadidae. No Pholadidae were recorded. 



A21.04 Fouling Agents 



1. Silt . Deposits of silt, rajiging from traces to- medium, 

 occurred on all the panels of both the control and test series. 



2. Algae . Algae, mostly green, occurred on 2 control panels 

 and on 5 test panels. The growths ranged from traces to light. 



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