471 
All their eggs in one basket: 
a rocky reef nursery for the longnose skate 
(Raja rhina Jordan & Gilbert, 1880) 
in the southern California Bight 
Milton S. Love (contact author ) 1 
Donna M. Schroeder 2 
Linda Snook 1 
Anne York 3 
Guy Cochrane 4 
Email address for M. S. Love: love@lifesci.ucsb.edu 
1 Marine Science Institute 
University of California 
Santa Barbara, California 93106 
2 Minerals Management Service 
770 Paseo Camarillo 
Camarillo, California 93010 
3 6018 Sycamore Avenue 
Seattle, Washington 98107 
4 United States Geological Survey 
400 Natural Bridges Dr. 
Santa Cruz, California 95060 
Skates (family Rajidae) are ovipa- 
rous and lay tough, thick-walled eggs. 
At least some skate species lay their 
eggs in spatially restricted nursery 
grounds where embryos develop and 
hatch (Hitz, 1964; Hoff, 2007). After 
hatching, neonates may quickly leave 
the nursery grounds (Hoff, 2007). Egg 
densities in these small areas may 
be quite high. As an example, in the 
eastern Bering Sea, a site <2 km 2 har- 
bored eggs of Alaska skate (Bathyraja 
parmifera ) exceeding 500,000/km 2 . 
All skate nursery grounds have been 
identified over soft sea floors (Lucifora 
and Garcia, 2004; Hoff, 2007). 
In 2005, while conducting fish 
surveys using a manned submers- 
ible over natural reefs in the Santa 
Barbara Channel, southern Califor- 
nia, we found an area of high skate 
egg density, located on the edge of 
Hueneme Submarine Canyon. Until 
that date, we had rarely observed 
skate eggs in our southern California 
surveys. For example, in 362 other 
submersible dives, in waters between 
18 and 365 m deep and encompass- 
ing 395 km of transects over a wide 
range of habitats, we had observed 
only 44 skate eggs. In 2006, we re- 
turned to the Hueneme Submarine 
Canyon site and examined this nurs- 
ery ground more closely. 
Material and methods 
We conducted the study on 24 October 
2006 on a feature located on the west 
side of Hueneme Submarine Canyon 
(Fig. 1). The study area is a rocky 
outcrop located at approximately 
34°02.3'N, 119°18.1'W. Rocks exposed 
at the site are likely a submerged 
extension of the Miocene volcanic 
rocks that make up Anacapa Island 
(Vedder et al., 1986). These rocks form 
gently north-dipping strata of volca- 
nic flows, breccias, conglomerates, or 
tuffs. Faults and joints observed on 
the Island, and from the submersible 
at the site, increase rock resistance 
against gravitational failure. Bathy- 
metric high spots, such as that of the 
skate nursery grounds, are north- 
dipping volcanic-layer outcrops that 
have not collapsed because of the local 
strength of the rock substrate in com- 
bination with the buttressing struc- 
ture formed by faulting and jointing. 
Several diminutive taxa, including 
squarespot ( Sebastes hopkinsi), sword- 
spine ( Sebastes ensifer), and pygmy 
( Sebastes wilsoni) rockfishes, domi- 
nate the fish fauna. Among structure- 
forming invertebrates, the volcanic 
outcrop also harbors high densities of 
barrel, flat, foliose, and vase sponges, 
gorgonian corals, the large anemone 
Metridium sp., basketstars, and the 
deep-water antipatharian coral Anti- 
pathes dendrochristos. 
This survey was conducted aboard 
the small (4.8 m in length) research 
submersible Delta (Delta Oceano- 
graphies, Ventura, CA). During the 
dive, we tried to maintain a constant 
distance within 1 meter of the sea- 
floor and a constant speed between 
0.5 and 1.0 knot. The survey was 
made during daytime hours and we 
documented the egg density of long- 
nose skates in that area with an ex- 
ternally mounted hi-8 video camera 
positioned above the middle viewing- 
porthole on the starboard side of the 
submersible. The scientific observer 
conducted a belt-transect survey 
through this same starboard viewing 
port, verbally recording onto the vid- 
eotape all skate eggs observed within 
2 m of the submersible. 
Navigation fixes (latitude and lon- 
gitude coordinates) were received 
from a Thales GeoPacific Winfrog 
ORE Trackpoint 2 USBL (Fugro- 
Pelagos, San Diego, CA) system at 
two-second intervals, and a Winfrog 
DAT file was generated for the re- 
search dive. Distance and duration 
between fixes were calculated to 
obtain a point-to-point submersible 
speed; errant navigation fixes were 
removed when speed exceeded 2 m/ 
sec. The navigation fixes were then 
smoothed by using a nine-point mov- 
ing average, and transect length was 
Manuscript submitted 14 February 2008. 
Manuscript accepted 13 May 2008. 
Fish. Bull. 106:471-475 (2008). 
The views and opinions expressed 
or implied in this article are those 
of the author and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
