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Fishery Bulletin 11 6(2) 
Figure 1 
Map of the study area (darker shaded area) in the Hawaiian Archipelago, where velvet 
dogfish (Zameus squamulosus) were collected in Hawaii longline fisheries between 2001 
and 2008 to determine their vertical distribution, diet, and reproductive stages. 
in the stomach of one individual. On the basis of exam¬ 
ination of a small number of reproductive tracts, velvet 
dogfish have been described as aplacental viviparous 
sharks that fit the type-II yolk-sac reproductive mode 
(in which several embryos with attached yolk sacs 
are contained in utero without uterine compartments) 
(Otake, 1990). 
Male velvet dogfish are thought to mature between 
493 and 522 mm in total length (TL) on the basis of 
clasper length and calcification of claspers (Krefft, 
1980; Yano and Tanaka, 1984). Size at maturity for 
females is less certain. Melendez (1991) reported that 
females 510-551 mm TL were immature. Pajuelo et al. 
(2010) reported the smallest mature female at 571 mm 
TL, and Compagno et al. (2005) found mature females 
at sizes of 590-690 mm TL. However, Yano and Tanaka 
(1984) found that a 720-mm-TL female was immature 
and reported sizes between 750 and 840 mm TL for 
mature females. Brood size for velvet dogfish is not 
known, but Yano and Tanaka (1984) reported 3-10 ova 
in uteri of females, which may indicate that brood size 
falls within a similar range. Estimates of size at birth 
have spanned a large range, most likely attributable to 
misidentification. Ebert (2015) stated size at birth as 
200 mm TL, and Cadenat and Blache (1981) reported 
free-swimming individuals as small as 246 mm TL. 
In contrast, Burgess and Chin (2006) reported sizes 
at birth of 68-90 mm TL. Individual velvet dogfish as 
large as 1094 mm TL have been noted (Pajuelo et al., 
2010); the maximum size was previously reported as 
840 mm TL (Yano and Tanaka, 1984). 
Specimens of the velvet dogfish are occasionally cap¬ 
tured in Hawaii longline fisheries that primarily target 
tuna species and swordfish (Xiphias gladius) (Walsh 
et al., 2009). Longlines that primarily target big eye 
tuna (Thunnus obesus) are typically set in the morning 
and hauled in the evening, and longlines that target 
swordfish are set in the evening and retrieved during 
the morning (Pooley, 1993; Pradhan and Leung, 2004). 
This fishery generally extends into the mid-North Pa¬ 
cific Ocean from the Equator to 40°N and between lon¬ 
gitudes 145°W and 175°E (Pradhan et al., 2003) (Fig. 
1). The capture of velvet dogfish as bycatch in the Ha¬ 
waii pelagic longline fishery provided an opportunity to 
expand our knowledge about this species. We present 
information on the depth distribution, diet, and female 
reproductive biology of velvet dogfish captured in Ha¬ 
waii pelagic longline fisheries. 
Materials and methods 
Vertical distribution 
We examined 21 velvet dogfish from waters off Hawaii. 
Identification was based on the key provided in Com¬ 
pagno (1984) and on proportional and morphometric 
measurements of specimens in Wetherbee and Crow 
