FISHERY BULLETIN: VOL. 74, NO. 3 



seven TT collections taken between 1,200 and 2,300 

 m. Finally, to present as much data as possible on 

 rare species, we have included more recent collec- 

 tions with 3- and 5-m IK, deep-day and shallow- 

 night TT collections, and a variety of CT and IK 

 tows made by the National Marine Fisheries 

 Service (NMFS). 



The lower depth limits given are subject to 

 question because most of the specimens con- 

 sidered were taken by the IK or CT, neither of 

 which were equipped with opening-closing 

 devices. As discussed in Clarke (1973, 1974), this 

 problem is not great in dealing with abundant 

 species, but for rare species-as were many con- 

 sidered here-there is no basis upon which to 

 discriminate captures made at the principal tow- 

 ing depth from those made in transit to and from 

 towing depth. Consequently, some of our conclu- 

 sions about depth ranges and vertical migration 

 must be regarded as tentative. 



Lengths of all specimens were measured to the 

 nearest millimeter. For each species discussed 

 individually, the total number examined and the 

 length range in millimeters are given in paren- 

 theses after the species name. (Unless noted as 

 TL-total length, SL or standard length is used.) 

 Gonads were examined under a dissecting 

 microscope to estimate size at maturity (defined 

 here as the smallest female with well-developed 

 ova), seasonal trends in gonad development, and 

 sex ratios. For rarely taken species, we examined 

 all specimens and have reported results for un- 

 damaged specimens large enough to be reliably 

 sexed by our routine technique. In species where 

 we examined only a fraction of the total available 

 material, we selected tows taken from throughout 

 the day and night depth range and from all 

 seasons and examined all individuals of the size 

 range of interest from these selected tows. 

 Hopefully this procedure minimized any potential 

 bias due to sexual differences in depth distribu- 

 tion, etc. In all cases where we discuss population 

 sex ratio, at least 50% (usually 70-80%) of the total 

 individuals of the appropriate size range were 

 sexed. 



Numbers of specimens captured per tow were, 

 for all species considered here, too low to treat in a 

 rigorous quantitative fashion. Consequently, we 

 have pooled data from all seasons to estimate 

 depth ranges, pooled fish from all depths to con- 

 sider seasonal changes in abundance, etc. Since 

 both depth coverage and eff^ort were roughly equal 

 for each of the seasonal series of collections, it is 



unlikely that any serious bias resulted from our 

 procedures. 



Specimens of all species considered here will be 

 deposited in the National Museum of Natural 

 History, Washington, D.C. 



Table 1. -Lengths and capture data for 11 species taken near 

 Hawaii (lat. 22°20-30'N; long. 158°20-.30'W) and two specimens 

 (*) taken in the central equatorial Pacific (lat. 3°30'N; long. 

 145°W). Total length is given for Isistius and Snijderidia; 

 standard length for the others. For horizontal tows, the most 

 frequently fished depth is given; oblique tows are noted by 

 0-ma.ximum depth. Catches by opening-closing trawl are noted 

 by (OC). 



636 



