FISHERY BULLETIN: VOL. 74, NO. 2 



123° 



.Oecjeption x^j,^_ Skagilj River 



Evei ett 



FIGURE 1. — Map of western 

 Washington, with the study areas 

 shown in inset: 1) Kiket Island sub- 

 tidal site; 2) Skagit Island subtidal 

 site: and 3) intertidal site. 



face. The 1-m depth test panels were suspended 

 from a steel surface float. The 6.1- and 15.3-m 

 depth test panels were suspended between a con- 

 crete bottom anchor and a steel float moored just 

 below the extreme low water level. At both test 

 sites three panels were deployed at each depth 

 (Figure 2). 



Series I test panels were exposed for periods of 

 41 and 79 days offshore from Skagit Island and 

 were exposed for 58 and 101 days offshore from 

 Kiket Island. Series II test panels were exposed 

 continuously for a period of 8 mo (16 April-29 

 November 1972) at both locations. 



The standard analytical procedure for series I 

 plates involved identification of the organisms, 

 estimation of the percent of plate coverage, and, if 

 possible, a measurement of the size of the or- 

 ganisms. A central square of each plate, measur- 

 ing 7 cm X 7 cm, was used for analysis. The fouling 

 organisms on each 49-cm2 central area were 

 scraped onto preweighed filter paper, dried at ap- 

 proximately 100°C for 24 h, and then weighed to 

 0.01 g. Monthly qualitative observations of series 

 II plates, anchors, lines, and floats were made using 

 scuba. 



Intertidal Fouling 



An examination was made of the settling rate of 

 intertidal fouling organisms on concrete slabs. 

 The concrete slabs measured 38 cm wide by 76 cm 

 long by 15 cm deep. The slabs were uniform in 

 texture, composition, surface configuration, sta- 

 bility, and resistance to wave action. They were 

 anchored to the beach with steel reinforcing bars 

 imbedded in the concrete. The long dimension was 

 parallel to the water and the top surface was 

 placed horizontal to the plane of the water. The 

 slabs were positioned at the +0.6-, 0-, -0.6-, and 

 — 1.2-m water levels relative to mean sea level. 

 Once each month the density of the fouling or- 

 ganisms was determined from a series of randomly 

 chosen 49-cm2 areas on each concrete slab. 



RESULTS 

 Physicochemical Environment 



Seasonal water quality data for the Kiket Island 

 area have been described in detail (Stober et al. 



378 



