207 
National Marine 
Spencer F. Baird /* ' . 
Fisheries Service 
Fishery Bulletin 
First U S. Commissioner J . q 
NOAA 
ft- established in 1881 
of Fisheries and founder */• & 
of Fishery Bulletin igW' 
Vertical distribution, diet, and reproduction of the 
velvet dogfish (Zameus squamulosus) in waters 
off Hawaii 
Gerald L. Crow (contact author ) 1 
Bradley M. Wetherbee 2 ' 3 
Robert L. Humphreys Jr. (retired ) 4 
Richard Young 5 
Email address for contact author: gcrow@hawaii.edu 
1 Waikiki Aquarium 
University of Hawaii at Manoa 
2777 Kalakaua Avenue 
Honolulu, Hawaii 96815 
2 Department of Biological Sciences 
University of Rhode Island 
9 East Alumni Road 
Kingstown, Rhode Island 02881-0816 
3 Guy Harvey Research Institute 
Nova Southeastern University 
8000 North Ocean Road 
Dania Beach, Florida 33004 
4 Life History Program 
Fisheries Biology and Stock Assessment Branch 
Fisheries Research and Monitoring Division 
Pacific Islands Fisheries Science Center 
National Marine Fisheries Service, NOAA 
1845 Wasp Boulevard, Building 1 76 
Honolulu, Hawaii 96818 
5 Department of Oceanography 
School of Ocean and Earth Science and 
Technology 
University of Hawaii at Manoa 
1000 Pope Road 
Honolulu, Hawaii 96822 
Abstract— The velvet dogfish (Zame¬ 
us squamulosus) is a wide-ranging 
species of shark that is captured as 
bycatch in bottom and pelagic long- 
line fisheries in the Atlantic, Pacific, 
and Indian oceans from near the 
surface to depths as great as 2000 
m. Here we provide information on 
the vertical distribution, diet, and 
reproduction of the velvet dogfish 
based on examination of 21 speci¬ 
mens captured in Hawaiian longline 
fisheries. Only females (576-839 mm 
in total length [TL]) were captured 
in waters off Hawaii and this find¬ 
ing may indicate sexual segregation 
for this species. All individuals were 
captured in epipelagic and pelagic 
oceanic waters at estimated target 
hook depths between 24 and 400 
m. Stomach and intestinal contents 
consisted of squid, fish, and shrimp. 
Females were immature at 576-729 
mm TL and mature at 715-839 mm 
TL. Mature females contained 6-10 
uterine eggs and 4-8 embryos. On 
the basis of results from a preg¬ 
nant female (715 mm TL), the size 
of ovarian ova, and the width of the 
uteri of slightly larger individuals, 
female maturity was estimated to 
occur at 715-730 mm TL. No repro¬ 
ductive seasonality was detected; 
however, our sample size was small. 
Reproductive data from published 
records for size of near-term embry¬ 
os and smallest free-swimming spec¬ 
imens with umbilical scars indicate 
that size at birth is 245-270 mm TL. 
Manuscript submitted 18 July 2017. 
Manuscript accepted 2 March 2018. 
Fish. Bull. 116:207-214 (2018). 
Online publication date: 16 March 2018. 
doi: 10.7755/FB. 116.2.9 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
The velvet dogfish (Zameus squamu¬ 
losus) is a dark, nondescript shark 
species with a wide distribution 
along the margins of the Atlantic, 
Pacific, and Indian ocean basins and 
at a number of insular regions, in¬ 
cluding the Canary Islands, Hawaii, 
Japan, New Zealand, Okinawa, and 
Palau (Compagno, 1984; Taniuchi 
and Garrick, 1986; Yano and Kugai, 
1993; Wetherbee and Crow, 1996; 
Pajuelo et ah, 2010). Although this 
species was placed in the genus 
Scymnodon before the revision by 
Taniuchi and Garrick (1986), the 
genus Zameus is genetically distinct 
from Scymnodon, and Zameus squa¬ 
mulosus is recognized as the valid 
name for the velvet dogfish (White 
et ah, 2014). This species occurs as 
bycatch in a variety of fisheries, in¬ 
cluding those using trawls and pe¬ 
lagic or bottom longlines (Krefft, 
1980; Yano and Tanaka, 1984; Na- 
kaya and Shirai, 1992; Pajuelo et 
ah, 2010; Zhu et al., 2012; Romanov 
et ah, 2013) at depths of 27-2000 m 
(Compagno, 1984; Last and Stevens, 
1994). 
Although the velvet dogfish has 
a wide distribution and is regularly 
captured, information about its basic 
life history remains fragmentary and 
has been hindered by misidentifica- 
tion. Not surprisingly, this species 
is categorized in the International 
Union for the Conservation of Na¬ 
ture (IUCN) Red List of Threatened 
Species as data deficient (Burgess 
and Chin, 2006), and the limited in¬ 
formation on its basic biology, which 
is required to assess the status of a 
stock or to evaluate fisheries impact 
on the population, is unavailable. 
Few records exist on the diet and 
reproductive biology of the velvet 
dogfish. Compagno (1984) suggested 
that these sharks feed on bottom 
fishes and invertebrates, and Ko- 
bayashi (1986) reported an octopus 
