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Fishery Bulletin 106(4) 
(Lower map) The general location (black box) of the longnose skate ( Raja 
rhina) nursery ground on the edge of Hueneme Submarine Canyon, south- 
ern California Bight. (Upper map) The area within the black box in the 
lower map has been enlarged and the white box represents the nursery 
ground within that area; the other white lines in the upper map denote 
transects followed by the Delta submersible. Transects outside the box 
did not contain skate eggs. 
estimated from the total distance between the smoothed 
points. Transect length was divided by transect dura- 
tion to obtain an average transect speed. The length of 
individual habitat patches was estimated from average 
speed of the submersible during each transect. 
During the survey, the observer verbally noted each 
egg or egg aggregation, estimated the number of eggs 
in the aggregation, and whether the eggs were living 
or dead. We assumed that yellow or green, shiny and 
full eggs still contained embryos and that those that 
were dark, deflated, and heavily biofouled were empty. 
It should be noted that in other studies dark egg cases 
have been found to still hold living embryos and thus 
our estimates of viability may be low. At that time, the 
observer also described whether the egg(s) had been 
laid on rock, cobble, sand, or on such structure-forming 
animals as sponges and gorgonians. Lastly, in order to 
identify the species using this nursery ground, five eggs 
were collected. 
In the laboratory, the abiotic habitats of the nurs- 
ery ground were also characterized from the survey 
videotape. We defined these habitats using the differ- 
ent categories of substrata and standard geological 
definitions defined by Yoklavich et al. (2000). In order 
