FISHERY BULLETIN: VOL. 87. NO. 4, 1989 



Table 1 . — Breakdown of the major groups of benthiic organisms, expressed as the 

 percentage of number of total organisms observed, for each of the three years of the 

 survey. These seven groups account for 97 to 99% of all megafaunal animals ob- 

 served in the areas surveyed for any given year. 



^^ 



# 



4- s? 

 « <f & 



/^ / i'/ ^ / »/ ^/ ^ / ^/ ^/ i/ ^ / i/ ^/ f/ ^/ ^ / 



muds 



sands 



gravels 



Figure 3. — Occurrence of dominant megafaunal groups associated with substrate type. Data is e.xpressed as numbers of 

 individuals per square meter of bottom for each sediment type. Only ta.xa that had a density of aO.Ol animals per squre meter in 

 any one sediment type are included in the figure. The actual density is given when it equals or exceeds the 0.01 value while a " + " 

 indicates presence but at a densit.y of <0.01 animal per square meter. The sediment types follow the terminology of Folk (1980) 

 and are cM = clayey mud, M = mud, M-Z = Mud-Silt, Z = Silt, sZ = sandy silt, (g)sM = slightly gravelly sandy mud, gM = 

 gi'avelly mud, (s)gM = slightly sandy gravelly mud, (g)mS = slightly gravelly muddy sand, gmS = gravelly muddy sand, S = 

 sand, (g)S = slightly gi-avelly sand, gS = gravelly sand, msG = muddy sandy gravel, sG = sandy gi'avel, and B = boulder field. 



clay and silt substrates. Cerianthus sp. (proba- 

 bly C. borealis, see Shepard et al. 1986), a bur- 

 rowing anemone, was also not especially sub- 

 strate specific. It was found over the entire 

 gradation of sandy substrates as well as some of 

 the silts, although it reached its highest density 

 (1.12 m~^) in slightly gravelly muddy sand. 

 Bolocera tuediae, on the other hand, is an 

 anemone that attaches to hard, rocky, sub- 

 strates. Consequently, it was observed in areas 

 of gravel and sand at a ma.ximum density of 0.17 



m"^. On the sandy substrates, these 

 anemones, as well as the few animals observed 

 on clayey mud, were often found attached to a 

 rock outcrop or loose boulder rather than di- 

 rectly to the finer sediment. The sea scallop, 

 Placopecten magellanicus, was restricted to 

 gravelly sand while pandalid shrimp occurred 

 on finer sands and muds; both at relatively low 

 densities, 0.01 and ^0.04 m~^, respectively. 

 Asteroidea which include a variety of genera 

 (e.g., Asterias, Hippasteria, Henricia, Cros- 



948 



