Scordino et al.: Dietary niche overlap and prey consumption for Eumetopias jubatus and Zalophus californianus 49 
Table 4 
Split-sample frequency of occurrence (SSFO) and estimated metric tons (t) of prey consumed by major prey group (family, order, 
or class) and by the lowest identifiable taxonomic group (indented) for prey consumed by California sea lions (Zalophus califor- 
nianus), based on examination of scat samples collected from 2010 through 2013 in northwest Washington. Numbers of different 
types of scat samples by season are also provided. The SSFO calculations for major prey groups and for the lowest identifiable tax- 
onomic groups were performed separately and, as a result, produced slightly different values. The total annual prey consumption 
was calculated by multiplying the SSFO pooled across spring, summer, and fall by the total prey consumption estimate, including 
the winter estimate of 553 t. 
Total Spring Summer Fall 
Sample type No. of samples 
Scat samples 50 
Samples containing identifiable prey 
Samples containing no identifiable prey 
Empty samples 
Prey consumption 5692 t 
Prey group SSFO 
Herrings, shads, sardines: family Clupeidae ‘ i : : ! ; 47.4% 
Pacific herring (Clupea pallasiz) : : i i : d 15.4% 
Clupeids, unidentified i j I : F : 14.5% 
Pacific sardine (Sardinops sagax) 3 : ! ; i J 11.4% 
American shad (Alosa sapidissima) : : : : : 8.2% 
Salmon: family Salmonidae : : : : ‘ : 13.9% 
Salmon or trout, unidentified : : : : , 3 13.4% 
Hakes: family Merlucciidae ; : ; ; : d 13.4% 
Pacific hake (Merluccius productus) : : : : : i 12.9% 
Rockfishes: family Sebastidae ; : J : : : 2.0% 
Rockfishes (Sebastes spp.) ; ; i } j : 1.9% 
Skates: family Rajidae : : : ' : } 1.1% 
Skates, unidentified d : i : 4 : 1.1% 
Dogfish sharks: family Squalidae : : ; : i : 6.0% 
Pacific spiny dogfish (Squalus suckleyi) i : : : : 4 5.8% 
Anchovies: family Engraulidae d : : : : : 5.8% 
Northern anchovy (Engraulis mordax) : : : : : b 5.5% 
Flatfishes: order Pleuronectiformes : : : : ‘ : 3.7% 
Arrowtooth flounder (Atheresthes stomias) F : i I : : 1.4% 
Righteye flounders, family Pleuronectidae I f : i I ; 1.2% 
Starry flounder (Platichthys stellatus) : ; ; ! : : 0.4% 
Dover sole (Microstomus pacificus) : ; ; d J : 0.4% 
Sanddabs (Citharichthys spp.) : ‘ / : I I 0.3% 
Flatfishes, unidentified I ; , : I X 0.1% 
Rex sole (Glyptocephalus zachirus) , F : : i I 0.0% 
Squids and octopuses: class Cephalopoda j : : : : A 1.6% 
Squids and octopuses, unidentified : : : , : : 0.4% 
Octopuses, unidentified ; i ; : , : 0.7% 
Squids, unidentified k : } ! i i 0.3% 
Cods: family Gadidae : : : : : : 1.7% 
Codfishes, unidentified : : : i i } 1.0% 
Pacific cod (Gadus macrocephalus) ; : I i : é 0.3% 
Pacific tomcod (Microgadus proximus) ; : ! I ! : 0.1% 
Walleye pollock (Gadus chalcogrammus) : 4 i i i i 0.2% 
Smelts: family Osmeridae 3 : : , i I 2.0% 
Smelts, unidentified F : : . : : 1.9% 
Eulachon (Thaleichthys pacificus) : : I I I : 0.1% 
Greenlings: family Hexagrammidae J : : : I I 0.5% 
Lingcod (Ophiodon elongatus) L , : : I i 0.2% 
Hexagrammids, unidentified L ! i I : i 0.2% 
(Continued on next page) 
