U.S. Dept Commerce/NOAA/NMFS/NWFSC/Publications

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NOAA-NWFSC Tech Memo-28: Impact of sea lions and seals on Pacific Coast salmonids

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Appendix F Summary of food habit studies of California sea lions in Washington, Oregon, and California Since 1970. Prey species noted are those which occurred in more than 10% of samples (except salmonids).

Area	Year	Sampling time period	n1	Prey	Percent of samples2	Methods	Source
Everett, WA	1979	May	9	Pacific whiting walleye pollock	unk unk	scat, spewings/otoliths	Everitt et al. 1981
	1986	April	100	Pacific whiting Pacific herring	88 26	scat, spewings/otoliths, bones	Gearin et al. 1988a
				salmonids	5
	1987	Feb, May	48	Pacific whiting Pacific herring dogfish shark	92 50 15	scat, spewings/otoliths, bones	Gearin et al. 1988a
				salmonids	6
Shilshole Bay, WA	1987	Feb to May	71	Pacific whiting squid Pacific herring dogfish shark	72 37 28 11	scat, spewings/otoliths, bones	Gearin et al. 1988a
				salmonids	25
Puget Sound, WA	1988	Dec to March	106	Pacific whiting Pacific herring dogfish shark codfish	34 30 19 12	scat, spewings/otoliths, bones	NMFS/AFSC data3
				salmonids	21
Columbia River	1980­81	Jan to June	16	eulachon anchovy lamprey Pacific herring Pacific tomcod sand sole	44 19 13 13 13 13	gastrointestinal tracts from beachcast sea lions/otoliths, bones, lenses, scales, flesh	Beach et al. 1985
				salmonids	13
Area	Year	Sampling time period	n1	Prey	Percent of samples2	Methods	Source
Columbia River (continued)	1991­93	Jan to May (one October sample)	18	eulachon rockfish Pacific herring lamprey sand lance	61 22 17 17 11	gastrointestinal tracts from incidentally caught sea lions and beachcast specimens/otoliths, bones, teeth, lenses, cartilaginous parts, beaks	Brown et al. 1995
				salmonids	28
East Mooring Basin, Columbia River	1992, 1993	March	110	salmonids	19	scat/otoliths, bones, teeth, lenses (for presence of salmonids only)	Riemer and Brown 1996
Cascade Head, OR	1994	February	82	mackerel smelt sardine cephalopods Pacific herring lamprey dogfish shark rockfish skate Pacific whiting sand lance anchovy	52 34 29 27 24 22 22 21 16 15 13 13	scat/otoliths, bones, teeth, lenses, cartilaginous parts, beaks	Riemer and Brown 1996
				salmonids	29
		October	38	Pacific whiting mackerel jack mackerel Pacific herring cephalopod	74 66 37 32 11	scat/otoliths, bones, teeth, lenses, cartilaginous parts, beaks	Riemer and Brown 1996
				salmonids	8
Area	Year	Sampling time period	n1	Prey	Percent of samples2	Methods	Source
Rogue River, OR	1976­78	Jan to June, Nov	86	salmonids	24	observations of actively feeding sea lions (86 observations)	Roffe and Mate 1984
	1978­79	March to May	28	lamprey	92	gastrointestinal tracts from collected animals/ otoliths, bones, teeth, flesh	Roffe and Mate 1984
				steelhead chinook	54 11
Klamath River, CA	1978­79	Spring	1126	lamprey	96	observations of actively feeding sea lions (1126 observations)	Bowlby 1981
				salmonids	1
		Apr, May, July	12	lamprey surf smelt eulachon	92 25 17	gastrointestinal tracts from beachcast sea lions/otoliths
				salmonids	8
		Apr, May	25	lamprey cephalopods Pacific whiting	52 16 16	scat/otoliths
				salmonids	4
Little Jackass Beach, CA	1980­82	Aug to Nov	24	Pacific whiting market squid Pacific herring	38 13 13	scat/otoliths, fish scales	J. B. Wexler, Humboldt State Univ., Arcata, CA. Pers. commun., April 1996.
Farallon Islands, CA	1974­78	Year-round	unk	Pacific whiting rockfish	unk unk	scat, spewings/otoliths only	Ainley et al. 1982
Año Neuvo Island, CA	1992	Summer, fall	115	Pacific whiting shortbelly rockfish market squid	47 53 52	scat/otoliths	NMFS/SWFSC data4
Area	Year	Sampling time period	n1	Prey	Percent of samples2	Methods	Source
San Francisco, CA, Pier 39	1993­94	Jan, Sep	76	Pacific herring spiny dogfish	common infrequent	scat/otoliths, bones, beaks Marine Mammal Center data
				salmonid smolts	infrequent
Channel Islands, CA	1981­93	Year-round	9513	market squid Pacific whiting shortbelly rockfish jack mackerel Pacific mackerel anchovy	common common common common common common	scat/otoliths	NMFS/SWFSC/ AFSC
				salmonids	trace

1. n = number of samples

2. Percent of samples (scat, stomach, etc.) examined that contained the identified prey. This is not the percentage of that prey in the total diet. Only species that occurred in quantities equal to or greater than 10% were included in this table (except salmonids, which were reported at any level).

3. National Marine Fisheries Service/Alaska Fisheries Science Center

4. National Marine Fisheries Service/Southwest Fisheries Science Center

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