APR. MAY JUN. JUL. AUG. SEP. OCT. NOV. DEC. JAN. FEB. MAR. APR. MAY JUN. 



FIGURE 31 ENCRUSTING BRYOZOANS, GROWTH-SET RELATIONS. 

 MEAN COLONY SIZE IN SQUARE INCHES IS USED AS AN 

 INDEX OF INDIVIDUAL COLONY GROWTH FOR A MONTH 

 OR SERIES OF MONTHS (CUMULATIVE). PERCENT 

 PANEL COVERAGE IN ASSOCIATION WITH NUMBERS 

 PER SQUARE FOOT SHOWS OVERALL GROWTH-SET 

 RATE AND INTENSITY PLUS AN INDICATION OF NUM- 

 BERS OF COLONIES VERSUS AREA COMPETITION. 



No mussels (Mytilis) occurred on the Site 1 monthly panels and only 

 small numbers, about 3 per square foot, on April-May and May-June 

 Site 2 panels (Fig 33). Cumulative mussel fouling for both Sites 1 and 2 

 show somewhat explosive populationincreases in the spring (particularly 

 in March-April) and early summer months (Figs 32 and 33), demon- 

 strating the importance of seasonal or even more critical timewise 

 introduction of equipments or test objects, and the possible effects of 

 seasonal foragers passing through an area. Mussels occurred on Site 

 1 3-month and 5-month cumulative panels in very limited numbers and 

 then not again until the 12-month April-April panel with 705 per square 

 foot, mostly in the size range 0-2 mm (Fig 32). 



33 



