Stevenson et at: Patterns of species richness, diversity, population density, and distribution in the skates of Alaska 
31 
Table 4 
Mean aggregate density (no. of individuals/km 2 , with standard error in parentheses) of all skates combined by subregion and 
depth range for bottom-trawl surveys conducted in the eastern Bering Sea (shelf and slope), Aleutian Islands, and Gulf of Alaska 
from 1999 through 2004. * = calculations for this area of the Bering Sea slope did not include the particularly large catch of B. 
parmifera on 29 June 2002 (see text for details). 
Subregion 
ueptn 
range (m) 
1 
2 
3 
4 
5 
6 
Total 
Bering Sea shelf 
<50 
51-100 
101-200 
Total 
86.20(10.09) 
220.24(16.53) 
216.34(38.33) 
185.06(12.25) 
191.85 (14.24) 
330.91 (15.70) 
215.94(14.67) 
263.22(9.58) 
340.92(119.05) 
175.03(9.74) 
292.13(11.16) 
238.91 (8.27) 
154.67 (10.46) 
245.31 (8.83) 
256.60(11.24) 
229.49(5.97) 
Bering Sea slope 
201-600 
311.32(43.28) 
492.60(83.61) 
328.23 (64.99) 
670.47 (121.44) 
277.00(57.20) 
797.53 (134.44)* 
466.14 (38.02)* 
601+ 
255.91 (48.04) 
1046.67(171.08) 
467.24(80.55) 
735.72(145.61) 
105.51 (18.05) 
784.85(111.65) 
547.59(47.09) 
Total 
292.63(32.92) 
774.03(101.66) 
398.81 (52.25) 
702.04(93.61) 
173.20(28.21) 
792.61(92.51)* 
501.29(29.69) 
Aleutian Islands 
<100 
101-200 
201+ 
Total 
135.65(77.68) 
279.19(55.00) 
69.72(30.45) 
184.78(32.47) 
44.54(7.89) 
50.33(7.95) 
99.90(14.49) 
66.94(6.55) 
55.32(15.28) 
110.12(29.89) 
219.66(32.47) 
147.4(18.83) 
21.51 (2.80) 
45.39(8.73) 
151.07(22.86) 
74.24(9.06) 
44.21 (8.38) 
113.06(15.03) 
149.39(13.72) 
109.38(7.96) 
Gulf of Alaska 
<100 
12.21 (1.68) 
35.60(6.11) 
31.92(4.10) 
67.41 (26.64) 
76.97(65.26) 
29.60(3.04) 
101-200 
12.52(2.36) 
43.31 (4.96) 
48.66(3.61) 
30.45(5.15) 
13.96(4.43) 
37.56(2.14) 
201+ 
18.08 (7.61) 
66.67(7.29) 
50.14(8.04) 
41.87(7.17) 
22.25 (4.84) 
46.10(3.59) 
Total 
12.75(1.38) 
46.67(3.5) 
42.94(2.66) 
42.16(6.13) 
24.52(7.16 ) 
36.65 (1.64) 
Table 5 
Mean and maximum density (no. of individuals/km 2 ) by species for skates collected in bottom-trawl survey hauls performed in 
the eastern Bering Sea (shelf and slope), Aleutian Islands, and Gulf of Alaska from 1999 through 2004. * = not collected in this 
region, n = total number of hauls performed within each region. 
Species 
Bering Sea shelf 
(71=2110) 
Bering Sea slope 
(tj = 483) 
Aleutian Islands 
(n=1409) 
Gulf of Alaska 
(71=2094) 
All regions 
(77 = 6096) 
Mean 
Max 
Mean 
Max 
Mean 
Max 
Mean 
Max 
Mean 
Max 
Bathyraja parmifera 
217.09 
5103.83 
55.00 
19759.77 
18.36 
1012.26 
1.64 
201.97 
84.30 
19759.77 
B. aleutica 
0.99 
575.15 
214.16 
3981.10 
8.52 
639.17 
5.07 
207.53 
21.02 
3981.10 
B. maculata 
0.01 
19.47 
43.07 
2350.51 
52.37 
4414.28 
0.12 
88.94 
15.56 
4414.28 
B. interrupta 
10.95 
565.55 
60.59 
1057.54 
1.01 
340.40 
5.60 
238.45 
10.75 
1057.54 
B. taranetzi 
0.13 
41.67 
31.48 
1117.97 
27.31 
1781.36 
0.02 
40.11 
8.86 
1781.36 
B. lindbergi 
* 
* 
78.02 
1953.68 
0.09 
46.22 
0.04 
82.24 
6.22 
1953.68 
B. minispinosa 
* 
* 
36.26 
1094.62 
0.11 
66.08 
0.02 
36.02 
2.90 
1094.62 
B. trachura 
* 
* 
26.79 
468.10 
0.08 
83.66 
0.69 
502.86 
2.38 
502.86 
B. mariposa 
* 
* 
* 
* 
0.34 
103.78 
* 
* 
0.08 
103.78 
B. abyssicola 
* 
* 
0.10 
26.42 
* 
* 
* 
* 
0.01 
26.42 
Raja rhina 
0.01 
44.67 
* 
* 
0.10 
50.81 
13.83 
592.97 
4.78 
592.97 
R. binoculata 
0.25 
197.37 
* 
* 
1.08 
178.52 
9.61 
986.51 
3.64 
986.51 
Amblyraja badia 
* 
* 
0.25 
80.00 
* 
* 
* 
* 
0.02 
80.00 
All skates 
229.43 
5103.83 
545.81 
22,005.20 
109.38 
4609.02 
36.65 
986.51 
160.52 
22,005.20 
