FISHERY BULLETIN: VOL. 84, NO. 3 



Table 3.— Morphological features, apparent in photographs taken from submersibles, used to 

 distinguish between four Ceriantharia species seen, and the geographic areas and bathymetric 

 ranges in which they were found (cf. Fig. 3, Appendix Tables 1 and 2). 



1 1 - Wilkinson Basin, Gulf of Maine; 2 - Georges Bank; 3 - Corsair Canyon; 4 - Lydonia Canyon; 5 - Gilbert 

 Canyon; 6 - Oceanographer Canyon; 7 - Hydrographer Canyon; 8 - Veatch Canyon; 9 - Block Canyon; 10 - Hud- 

 son Canyon. 



2 Used by Meyer (1980) to characterize feeding nets of other passive suspension feeders. 



U 

 



23 



1 



3 



U 20 



IS 



IB 



S 







30 

 23 

 20 

 IS 



10 



S 

 



3 5 9 16 



DEPTH (M X IBB) 



4 8 12 16 20 

 TEMPERATURE RRNGE (AT.°C) 



_ra. 



2 3 4 



SEDIMENT TYPE 



observed at depths from 400 to 1,600 m, and Ceri- 

 anthid A was seen at depths from 1,600 to 1,930 m 

 (Table 3). 



Relation to Bottom Water Temperature 



Temperature observations were sparse for grab 

 sample stations, so, the extreme range of temper- 

 ature (A T), a commonly used measure of climatic 

 variability (MacArthur 1975), was used to compare 

 temperature with Ceriantharia distribution; A T 

 equals the difference between extreme annual 

 recorded temperatures (summer high minus winter 

 low), obtained from various published sources, and 

 measurements, made by the NEFC. Site ranges 

 were grouped for plotting: 0° to 3.9°C, 4° to 7.9°C, 

 8° to 11.9°C, 12° to 15.9°C, 16° to 19.9°C, and 

 >19.9°C. Temperature range changed significant- 

 ly with latitude and depth. Largest A T's generally 

 dominated shelf waters south of lat. 41°N, and in- 

 shore waters (Fig. 5). 



Ceriantharia occurrence at grab sample stations 

 was not independent of temperature range (x 2 , P < 

 0.05); occurrence was highest on the continental 

 shelf where A T was from 8° to 15.9°C (Fig. 4). 



All submersible dives were performed in July or 

 August. Bottom water temperatures (external 



Figure 4.— Ceriantharia occurrence (% of grab sample stations) 

 in relation to latitude, depth, temperature range (AT = summer 

 high minus winter low), and sediment type. Depth stratum size 

 was determined by pooling, from shallow to deep, adjacent 100 

 m depth intervals until enough observations were available for a 

 chi-square test. Sediment type codes are 1 - gravel; 2 - 

 gravel/sand, silt, mud or clay; 3 - sand; 4 - silt/sand; 5 - silt/clay. 



632 



