submerged "between September 26, 19k6 and March 27, 19^7, when -Qie test 

 was discontinued; there was only one Limnorla during Decemiber 19i«-6 and none 

 during January and February 19^7- It thus appears that at this location the 

 migration of Limnoria ceases, or practically ceases, during the winter sea- 

 son. 



Limnorla occurred on eTer7' one of t.^ > 50 test panels. From the 

 time the first hoard was installed there i is, in general, a gradual in- 

 crease in the population imtil a peak rating of medixun heavy was attedned 

 in the panels removed ahout the first of December and January, after 

 having heen suhmerged for 9 months. A peak rating of medium heavy was 

 attained again in 19^6. At the location where the second board was in- 

 stalled in September 19^6 there was a gradual increase in the Limnoria 

 population, hut it did not exceed a trace even in panels submerged up to 

 6 months. 



A5 . Oil- Foiaing Agents 



1. Silt . Silt occurred as traces or occasionally as light de- 

 posits on each of the 50 control panels. It also occurred as traces, 

 and more frequently as light or sometimes heavy deposits, on each of 

 the same number of test panels. 



2. Invertebrate animal phyla . 



a. Coelenterata (hydrolds ) . Hydroids occurred as traces on 

 ik of the 50 control panels. In general, their development was confined 

 almost entirely to the late summer, fall, and esirly winter months. They 

 also occurred as traces, or occasionally as light growths, on all except 

 k of the 50 test panels. Tuhularia was the only form identified. 



b. Bryozoa (encrusting and filamentous) . Encrusting Bryozoa 

 occurred only sporadicailly and were generally few in nuoiber. Bryozoa were 

 recorded on a single conixol panel and on 9 of the 50 test panels; they 

 developed most consistently in test panels removed from November 19^^ to 

 March 19^7^ after 2 to 6 months* submergence. Tegella unicornis and 

 Electra were the only forms identified. 



c. Annelida (annelid worms ). A few specimens of Seirpula 

 occurred on a single test panel. 



d. ArthroDoda (cryiBtacteans) . Balemus (barnacles) occurred 



on only k of the 5<5 control panels. The barnacles occurred intermittently 

 for some periods on 17 of the 50 test panels and were absent for other 

 periods between times. They appeared to occur most frequently on panels 

 that were submerged during the warmer portion of the year. These barnacles 

 in the control panels were either minute or Juvenile. A maxinmm size of 

 10 mm was recorded on the test panels submerged for k, 9, and ik months. 

 Four of the latter panels were from 20^ to 100^ covered. nn-rnpirtiiTn hwi- 

 phlpode were recorded as occurring sporadically on 5 of the control 

 parsls and on 2 of the test panels. The majcimum number found on any 

 panel was 25. 



32 



