maximum absorbance at 499 nm, a value which is 

 typical of coastal fishes (McFarland 1970). Cres- 

 citelli (1969) and Beatty ( 1969), however, have re- 

 ported that H. colliei, which can occur in water 

 only 5 m deep, possesses retinal pigments charac- 

 teristic of deepwater fish iKmns = 484 nm). Cres- 

 citelli ( 1969) remarked that it is anomalous to find 

 such pigments in a coastal species. 



Like the retinal pigments, the structures for 

 regulating the amount of light striking the retina 

 in this species seem to be adapted to deep water. 

 Maddock and Nicol ( 1978) found that the pupils of 

 H. colliei cannot be contracted in bright light, and 

 the reflective tapetum lucidum has no movable 

 layer of dark pigments to eliminate eyeshine in 

 bright light. While Stell has found that there is 

 an increase in pigmentation on the tapetum after 

 full light adaptation, he estimated the degree of 

 occulsion at 209c or less. Stell also indicated that 

 ratfish appear to have an all-rod retina, a further 

 adaptation to low light levels. In attempting to 

 relate the spectral sensitivity of chimaeroid ret- 

 inal pigments to depth of occurrence, Crescitelli 

 (1969) and McFarland ( 1970) both noted that the 

 absence of behavioral or ecological data on H. col- 

 liei makes it difficult to classify this species as an 

 inhabitant of deep, shallow, or intermediate 

 depths. 



In the Gulf of California, H. colliei is typically 

 captured below 275 m, although abundance varied 

 seasonally (Matthews 1975). In other parts of its 

 geographic range this species clearly inhabits 

 shallower water. Jopson (1958) observed ratfish 

 trapped in tide pools on the Oregon coast, and 

 Dean ( 1906) reported catching them in about 4 m 

 of water in Port Townsend Bay, Wash. 



Recent studies have suggested that ratfish may 

 undergo diel onshore migrations in Puget Sound. 

 Miller et al.^ reported trammel net catches of 

 ratfish at night in areas where none were observed 

 by scuba divers during the day. Moulton (1977) 

 observed ratfish only in the evening and at night 

 during dives on rocky reef sites. However, other 

 divers (unpubl. obs.) have reported occasional 

 sightings of ratfish in shallow water during the 

 day 



^William K. Stell, Professor of Ophthalmology and Anatomy, 

 Jules Stein Eye Institute, University of California, Los Angeles, 

 Los Angeles, CA 90024, pers. commun. January 1978. 



^Miller, B. S., C. A. Simenstad, and L. L. Moulton. 

 1976. Puget Sound baseline program: Nearshore fish sur- 

 vey. Unpubl. manuscr., 196 p. Univ. Wash., Fish. Res. Inst. 

 FRI-UW-7604. 



To further understand the relationship between 

 visual systems and fish depth distribution, the 

 present study was designed to focus on three 

 questions. First, what is the overall bathymetric 

 distribution of ratfish in Puget Sound? Second, to 

 what extent do Puget Sound ratfish undergo sea- 

 sonal and diel onshore migrations? Third, is there 

 evidence for size- or sex-related patterns of abun- 

 dance or movements? 



Methods 



Seven sites in central Puget Sound were sam- 

 pled between 1965 and 1978: Port Madison, Port 

 Gardner, Mukilteo, Duwamish Head, Point Pully, 

 Alki Point, and West Point (Figure 1). Samples 

 were obtained with a 6 m otter trawl and a 6 m 

 beam trawl which we have previously found to fish 

 with approximately the same results. All tows 

 were on the bottom for 5 min. 



■^~^ 



— n — TFT^ 





Severe TT 



7il T ^ 



\S f TACOMA 



FIGURE 1.— Map of Puget Sound, Wash., with sites where 

 ratfish were sampled. 1, Eagle Cove; 2, Port Townsend Bay; 3, 

 Port Gardner, 4, Mukilteo: 5, Port Madison; 6, West Point; 7, 

 Duwamish Head; 8, Alki Point: 9, Point Pully 



817 



