Scharf et al.: Diet analysis of piscivorous fishes 
581 
Table 2 
Least squares regression equations relating measurements of body depth (BD), eye diameter (ED), caudal peduncle depth (CP), 
and pectoral-fin length (PF) to total length (TL) and fork length (FL) for ten prey species in the Northwest Atlantic. All measure- 
ments are in millimeters. s b = standard error of the regression coefficient; r 2 = coefficient of determination; %PE = mean percent 
prediction error; n = number of fish measured; Range = size range in total length. Fork lengths were not measured for red hake, 
silver hake, or Atlantic cod. 
Total length Fork length 
Species 
Equation 
s b 
r 2 
%PE 
Equation 
S 6 
r 2 
%PE 
n 
Range 
Alewife 
TL = 3MIBD + 11.012 
0.073 
0.95 
4.38 
FL = 3.469BD + 10.856 
0.067 
0.98 
4.04 
137 
73-282 
TL = 24.906 ED - 61.344 
0.781 
0.88 
7.30 
FL = 23.335 ED - 57.728 
0.562 
0.96 
6.13 
137 
73-282 
TL = 12.876 CP- 1.784 
0.182 
0.97 
3.53 
FL = 11.348CP + 1.313 
0.163 
0.99 
3.31 
137 
73-282 
TL = 6.840 PF + 0.532 
0.100 
0.99 
3.15 
FL = 5.982 PF + 1.785 
0.093 
0.98 
3.34 
66 
73-282 
Blueback herring 
TL = 4.97 OBD + 1.439 
0.268 
0.91 
3.59 
FL = 4.620BB - 1.573 
0.246 
0.91 
3.66 
38 
83-134 
TL = 25.318-ED - 35.605 
2.117 
0.80 
5.33 
FL = 23.792 ED - 37.352 
1.865 
0.82 
5.42 
38 
83-134 
TL= 13.684CP + 0.194 
0.752 
0.90 
3.53 
FL = 12.585CP- 1.782 
0.754 
0.89 
4.06 
38 
83-134 
TL = 7.760 PF + 2.935 
0.383 
0.92 
3.58 
FL = 7.198PF- 0.005 
0.358 
0.92 
3.79 
38 
83-134 
Atlantic herring 
TL = 4.561BD + 27.341 
0.089 
0.97 
4.22 
FL = 4.036 BD + 26.880 
0.081 
0.97 
4.17 
84 
97-295 
TL = 26.717BD - 51.235 
0.594 
0.96 
5.08 
FL = 23.633 ED - 42.586 
0.537 
0.96 
5.00 
84 
97-295 
TL = 16.303CP - 17.288 
0.296 
0.97 
4.55 
FL = 14.441CP- 12.792 
0.257 
0.97 
4.35 
84 
97-295 
TL = 7.507PF + 1.533 
0.101 
0.99 
2.68 
FL = 6.631 PF + 4.306 
0.102 
0.98 
2.95 
84 
97-295 
Atlantic mackerel 
TL = 5.203 BD + 37.203 
0.122 
0.97 
3.67 
FL = 4.641 BD + 39.790 
0.118 
0.97 
3.89 
56 
158-330 
TL = 33.706 ED - 81.239 
3.027 
0.70 
10.83 
FL = 30.404BZ) - 68.847 
2.652 
0.71 
10.28 
56 
158-330 
TL = 4Q.081CP - 0.837 
0.700 
0.98 
2.78 
FL = 35.874CP + 5.213 
0.592 
0.99 
2.61 
56 
158-330 
TL = 9.037 PF- 1.242 
0.178 
0.98 
3.02 
FL = 8.068 PF + 5.346 
0.172 
0.98 
3.06 
56 
158-330 
Butterfish 
TL = 2.880 BD + 1.650 
0.038 
0.98 
3.32 
FL = 2.384 BD + 5.638 
0.034 
0.98 
3.57 
108 
54-193 
TL = 2Q.065FD - 21.148 
0.635 
0.90 
7.48 
FL = 16.700ED - 13.166 
0.544 
0.90 
7.52 
108 
54-193 
TL = 17.96QCP+ 7.962 
0.290 
0.97 
3.57 
FL = 14.950CP + 11.046 
0.264 
0.97 
4.03 
108 
54-193 
TL = 3.76 6PF + 15.966 
0.060 
0.98 
4.33 
FL = 3.126PF+ 18.121 
0.064 
0.98 
5.54 
63 
54-193 
Sand lance 
TL = 7.308 BD + 58.774 
0.455 
0.78 
6.07 
FL = 7.0453D + 57.497 
0.463 
0.76 
6.16 
75 
109-209 
TL = 49.467FD - 45.022 
4.358 
0.64 
8.29 
FL = 47.921 ED - 43.479 
4.313 
0.63 
8.45 
75 
109-209 
TL = 35.928CP + 8.185 
1.562 
0.88 
4.32 
FL = 34.923 CP + 7.599 
1.575 
0.87 
4.48 
75 
109-209 
TL = 14.993PF- 31.272 
0.934 
0.78 
6.52 
FL = 14.542PF- 30.374 
0.933 
0.77 
6.75 
75 
109-209 
Red hake 
TL = 6.398BD + 10.340 
0.210 
0.96 
7.40 
45 
108-340 
TL = 28AUED - 91.519 
0.880 
0.96 
6.37 
45 
108-340 
TL = 26.384CP- 17.165 
0.627 
0.98 
5.18 
45 
108-340 
TL = 6.885PF - 0.693 
0.146 
0.98 
3.92 
45 
108-340 
Silver hake 
TL = 6.48GBD + 18.219 
0.164 
0.94 
7.00 
95 
75-300 
TL = 21.998SD - 31.654 
0.504 
0.95 
7.05 
95 
75-300 
TL = 22.823 CP + 22.881 
0.345 
0.98 
4.63 
95 
75-300 
TL = 4.946PF + 20.269 
0.070 
0.99 
3.36 
60 
75-300 
Haddock 
TL = 4.199M) + 21.964 
0.173 
0.93 
5.30 
FL = 4.066 BD + 19.660 
0.164 
0.93 
4.83 
47 
79-202 
TL = 20.069 ED - 35.473 
1.375 
0.83 
7.97 
FL = 19.525 ED - 36.724 
1.291 
0.84 
7.87 
47 
79-202 
TL = 18.465CP + 18.596 
0.699 
0.94 
4.90 
FL = 17.922CP + 14.205 
0.638 
0.95 
4.54 
47 
79-202 
TL = 7.367 PF- 10.712 
0.260 
0.95 
4.69 
II 
0 
ey> 
3 
1 
CO 
O 
0.263 
0.94 
4.90 
47 
79-202 
Atlantic cod 
TL = 4.249BD + 21.367 
0.133 
0.97 
4.03 
31 
52-140 
TL = 19.393 ED - 19.490 
1.053 
0.92 
7.33 
31 
52-140 
TL = 17.999CP + 9.806 
0.480 
0.98 
3.72 
31 
52-140 
TL = 6.728PF + 7.681 
0.185 
0.98 
3.48 
31 
52-140 
possess only two clearly definable margins and are 
curved along the entire posterior margin (Fig. II). 
Cfeithra 
In higher teleost fishes, the cleithrum is the ventral 
most bone of the pectoral girdle, which consists of 
the supracleithrum, the cleithrum, and the postclei- 
thrum. The cleithrum attaches directly to the scap- 
ulocoracoid, which articulates with the base of the 
pectoral fin. Together, the left and right cleithra form 
the frame of the body wall directly posterior to the 
branchial cavity. The cleithra of the fishes examined 
here can be differentiated by their general shape as 
