### 2006 Southern Resident Killer Whale Symposium NOAA Fisheries Service Northwest Regional Office April 3-5, 2006, Seattle WA 98103 Extended Abstract


## Regional patterns of persistent organic pollutants in five Pacific salmon species ( Oncorhynchus spp ) and their contributions to contaminant levels in northern and southe rn resident killer whales ( Orcinus orca )

O’Neill, Sandra M. 1 

### ; Ylitalo, Gina M. 2 

### ; West, James, E. 1 

### ; Bolton, Jennie 2 

### ; Sloan, Catherine A. 2 

### ; Krahn, Margaret M. 2

1 Washington Department of Fish and Wildlife, 600 Capitol Way North, Olympia WA 98501-1091
2 NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Blvd. E., Seattle, WA 98112



### Previous studies on killer whales ( Orcinus orca ) have shown that southern residents contain higher concentrations of persistent organic pollu tants (POPs) than northern residents (Ross et al ., 2000; Rayne et al ., 2004) and other North P acific resident killer whale populations (Ylitalo et al ., 2001; Herman et al ., 2005). Elevated contaminant exposure in southern residents may be attributed to dietary differences between the two whale populations or to regiona l differences in concentratio ns of POPs in their prey. Based on observational data and st omach contents analyses, Ford et al . (1998) identified Pacific salmon ( Oncorhynchus spp ), especially Chinook salmon (O. tshawytscha ), as the primary prey of southern and northern reside nt killer whales in their summer feeding ranges. The main objective of this study was to determine if Pacific salmon had speciesspecific regional body burdens of contaminan ts that could differentially affect contaminant levels is northern and southern residents. An additional objective was to measure proximate composition (amount of protein, lipid and car bohydrate) and estimate caloric content of Pacific salmon as an i ndicator of species- a nd regionally-specific variation in nutritional quality of prey to killer whales.

Free-ranging populations of anadromous Paci fic salmon are generally assumed to have low levels of POPs because the majority of their growth (and therefore contaminant uptake) occurs in open water of the Pacific Ocean. However, the oceanic distributions of the five Pacific salmon species ( i.e ., Chinook, coho, chum, pink, sockeye) differ and, as a result, can influence their exposure to contam inants. For example, when pink, chum and sockeye salmon enter the marine environmen t, they rapidly migrate northward and westward through coastal waters of North Am erica and are found in the open waters of the North Pacific, Gulf of Alaska and Beri ng Sea by the end of their first year at sea (Quinn, 2005). In contrast, Chinook and coho, have a more coastal marine distribution along the continental shelf co mpared to other salmon popul ations, although, populations within these two species can also differ in their marine distribution (Quinn, 2005).

To determine if Pacific salmon populations present in the summer feeding areas of northern and southern resident whales had species- and re gionally-specific body burdens of contaminants, we analyzed POPs in whol e body samples of five species of Pacific

### salm on collected from northern British Colum b ia to the c e ntr a l Calif ornia coast. All f i ve species were each samp led in two regions, the n on-urbanize d north-central co ast of British Co lu mbia that is f r equented b y nor thern r e siden tkille r whales and in the urbanized Puget Sound - Strait of Juan de Fuca region that is f r equented more by southern resident killer whal es (Table 1). Additionally, Chinook salm on were samp led in the coastal waters on the inside of Vancouve r (near Robson Bight), the Lower Columbia River (spring and fall runs) a nd cen tral co ast of California (Table 1). We sa mp led
term inal m a rine and in-river fisheries, at ti m e s aligned with the retu rn tim e for specific salm on stocks, to increase the likelihood of sa mp ling particular stocks of fish returning to a specific river. The presum ed river-stock asso ciated with each samp ling location is noted in Table 1.

Tabl e 1. N u mb er o f i n di vi du al fi sh o f eac h speci es c o llected at eac h sam p ling location for chem ical,
pr o x i m at e and st abl e i s ot o p e anal y s es. C o nt am i n ant s sam p l e s were ba sed on w h ol e b o d y sam p l e s of i ndi vi dual C h i n o o k sal m on a n d com posi t e s a m p l e s (5

- 6 i n di vi d u al s) f o r ot he r sal m on s p eci es. P r o x i m at e analyses we re base d on com posite sam p les of m a les or fem a les, each with 2-3 fis h per c o m posite. Note: On ly 1 3 of t h e Fraser an d 20 o f th e C o lu m b ia Riv e r Fall Chin oo k were an alyzed fo r con t amin an ts bu t proxim a t e analyses were base d on all fish collected.

F a l l Spr i ng R e s i d e nt
Ch a t a m So u nd Sk e e na 3 0 2 9 30

De a n C h a nne l K i m s qui t 3 0 3 0 E a st co a s t Va nc o u v e r Is l a nd ne a r Ro b s o n Bi g h t F r as er/ Ni m p kish 3 0 Lo pe z So u n d F r a s e r 3 0
Sk a g i t Riv e r S ka g i t 3 0

ne a r Ap pl e Co v e P o in t Pu ge t So un d mi x e d 3 4 3 0 1 1

N o o k sa ck / Du w a m i sh / N i s qua l l y ri v e rs Pu ge t So un d mi x e d 3 6 2 9

Co lu m b ia Riv e r Lo w e r Co lu m b ia Riv e r C o l u m b i a 3 0 2 0

C e n t r a l c oas t

o f

C a l i f or n i a ne a r Po i n t Ar e n a S a c r am en t o / Jo a q u i n 29 Sp e c i e s C h i n oo k S oc k e y e P i n k C h u m C o h o Ri v e r S t oc k Or i g i n Sa m p l i ng Lo c a t i o n Re g i o n

Str a i t o f J u a n d e F u c a / Pu ge t So un d Nort h / c e n t ra l

co a s t BC

### Overall, concentrations of POPs were hi gher in coho and Chinook populations that have more coastal distributions than those m easured in salm on species (e.g., chum, pink, sockeye) with m o re oceanic distributions . For pink, chum , a nd sockeye salm on, PCB levels were higher for fish ca ught in the m o re urbanized re gion of Puget Sound/Strait of Juan de Fuca region than in the less urbani z e d n o rth/central coast of British Colum b ia area, whereas concentrations of DDTs were sim i lar between regions. PBDEs were below the lim it of quant itation in all pink, c hum and sockeye samp led in this study. Concentrations of PCBs , PBDEs and DDTs wer e higher in coho salm on from Puget Sound comp ared to coho from the central BC coast. Regional vari ation in POP exposure was also evident in Chinook salm on (Figure 1) and appears to be associated with differences in m a rine distribution of th ese species. For example, Chinook salm on returning to Puget Sound had significantly higher concentrations of PCBs and PBDEsng/g wetweight

0 20 40 60 80 100

Spri ng Ru n C h in ook Fall R un Chi nook R e sid ent C h in ookng/g wet weight

0 10 20 30 40 50ng/gwet weight

0 10 20 30 40 50

c e ntr al CA Col u mb ia Riv e r P u g e t S o un d e astern V anc. I

. north e r n BC <1pp b < 1pp b P CBs

P BDE s

DD T s

Fi gu re 1. C o n centr at i o ns of persi s t e nt o r ga ni c p o l l u t a nt s ( + 9 5 % C I) i n wh ol e bo dy sa m p l e s of i n di vi dual C h i n oo k sal m on ca ug ht i n t e r m i n al fi shi n g ar eas. R i ve r pop u l ation s represen ted in clud e fish return i n g to the Sac r am ento/San J o aquin (central C A ; n = 2 9 )

, t h e C o l u m b i aR i ver (sp r i n g r u n n = 2 0 ; fal l ru n n = 1 7 )

, the Nooksack, Duwam i sh and Nisqually ( P ug et So und ; n = 3 6 )

, th e Fr as e rand Nim pkish (eastern c o ast Vanc o uve r Isl a nd; n = 1 3 ; G e o rgi aB a si n) a n d t h e S k ee na ri v e rs (n ort h er n B C ; n= 30 ). A d d i t i onal l y dat aar esho w n fo r s u b- adul t c h i n o o k s a lm on t h at wer e resi de nt i n P uget So u n d i n t h e wi nt er m ont hs (t erm e d “reside n t chi nook” n= 34).



### comp ared to other Pacific coast salm on populations we samp l e d. Furthermore, Chinook salm on that resided in P uget Sound in the winter rather than m i grate to the Pacific Ocean (“residents”) had the highest concentrati ons of POPs, followed by Puget Sound fish populations believ e d to be m o re ocean-rear ed. F a ll Chinook from Puget Sound have a more localized m a rine distribution in P uget Sound and the Georgia Basin than other populations of Chinook from the wes tcoast of North Am erica and are m o re contam i n ated with PCBs (2 to 6 tim es) and PBDEs (5 to 17 times).

Overall, the total caloric content per kg of fish was higher for Chinook and sockeye salm on than the other salmon species we samp led, due to their higher fat content. Moreover, b ecause of th eir greater size, the total Kcal per fish was highest for Chinook salm on. Regional differences in calori c content am ong Chinook populations were also observed. P uget Sound Chinook had lower calori c content (total Kcals per fish) than summer/fall run of Chinook salm on fr om all re gions we samp l e d (Figure 2). Assum i ng that the f i sh we samp led were representative of the sizes of fis h available f o r killer whale

consumption, whales feeding on non-resi dent C h inook salm on in Puget Sound would need to eat 1.5 to 1.8 tim es as m a ny Chi nook salmon as animals feeding outside Puget Sound to obtain the sam e caloric content.AverageKcalperFish

0 50 00 100 00 150 00 200 00 250 00 Sp ri ng Ru n C h i n ook Fall R u n Ch ino o k Re s i de nt C h i n oo k

ce ntr a l

CA Colum b ia Ri v e r P uge t Sound east e r n Va n c . I

. nor the r n BC Figure 2. Ave r age estim ated caloric c onte n t ( + 9 5 % C I ) of w hol e b ody sa m p l e s of i n di vi dual C h i n o o k salm on ca ug ht i n t e rm i n al fi sh i ng ar eas. R i v e r po p u l a t i ons rep r ese n t e d i n c l ude fi sh ret u r n i ng t o t h e Sacram ento/San J o a qui n (ce n t r al CA), t h e C o lum b ia Ri ver (sp r i n g a n d fal l r uns ), t h e N o o k sac k

, D u wam i sh

an d N i squ a lly ( P ug et Soun d) , th e Fr aseran d N i m p k i sh (eas tern c o ast Vancouve r Island) and the Skee na ri ver s ( n ort h er n B C )

.


### In summ ary, regional body burdens of c ontam inants in Pacific salm on, a nd Chinook salm on in particular, could contribute to the higher levels of contam inants in southern resident killer whales. In addition to contam ination, re gional differences in caloric content of Chinook salm on from Puget Sound fu rther reduce their quality as prey to southern resident k iller whales.

### References

Ford JKB, Ellis GM, Barrett-Lennard LG, Morton AB, Palm RS, Balcomb III KC. 1998. Dietary specialization in two sympat ric populations of killer whales ( Orcinus

orca ) in coastal British Columbia and adjacent waters. Can. J. Zool . 76(8): 1456- 1471.

Herman, D.P., Burrows, D.G., Wade, P.R., Du rban, J.W., LeDuc, R.G., Matkin, C.O., & Krahn, M.M. (2005) Feeding ecology of easte rn North Pacific killer whales from fatty acid, stable isotope, and organochlo rine analyses of blubber biopsies. Mar. Ecol. Prog. Ser . 302: 275-291.

Quinn TP, 2005. The Behavior and Ecology of Pacific Salmon and Trout. American Fisheries Society, University of Washington Press, Seattle, Washington. 378 pp.

Rayne S, Ikonomou MG, Ross PS, Ellis GM, Barrett-Lennard LG. 2004. PBDEs, PBBs, and PCNs in three communities of free-ranging killer whales ( Orcinus orca ) from the northeastern Pacific Ocean

. Environ

. Sci

. Technol . 38(16): 4293-4299.

Ross PS, Ellis GM, Ikonomou MG, Barrett-Lennard LG, Addison RF. 2000. High PCB concentrations in free-ranging Pacific killer whales, Orcinus orca : Effects of age, sex and dietary preference. Mar

. Pollut

. Bull . 40(6): 504-515.

Ylitalo, GM, Matkin CO, Buzitis J, Kra hn MM, Jones LL, Rowles T, Stein JE. 2001. Influence of life-history parameters on organochlorine concentrations in freeranging killer whales ( Orcinus orca ) from Prince William Sound, AK. Sci. Total Environ. 281: 183-203.