LEE W. HARRELL

MFR PAPER 1291

Vibriosis and Current Salmon VaccinationProcedures in Puget Sound, Washington

ABSTRACT-The National Marine Fisheries Service aquaculture experimentstation and several private salmon farms are successfully vaccinating fish againstvibriosis via automatic syringe. Delivery systems other than injection are currentlybeing researched and developed by private, governmental, and Sea Grant agen­cies. EVidently, there is some cross-protection offered by the original Vibrio anguil­larum isolate against a new vibrio species recently isolated at the Manchester,Wash., laboratory.

Lee W. Harrell is with the Northwestand Alaska Fisheries Center, Na­tional Marine Fisheries Service,NOAA, 2725 Montlake Blvd. East,Seattle, WA 98112.

tali ties in our experimental fish wereapproximately 10 percent, which wasdecidedly more acceptable than the60-90 percent losses that had been ex­perienced before the use of chemicaltherapy or prophylaxis.

Domsea Farms had slightly over amillion fish in saltwater pens in ClamBay during the fall of 1973. Substantiallosses began occurring in one of thelarger net pens during November, andthe moribund and dead fish were show­ing pronounced lesions typical of vib­riosis.

At this time Domsea Farms had nopathology facilities and NMFS ob­tained several of the diseased speci­mens for a diagnostic workup. Vibrioorganisms were isolated, but thegrowth characteristics were markedlydifferent from those we had previouslyencountered. This organism was des­ignated Manchester isolate #1669, andwe began to further characterize itserologically and biochemically.Domsea Farms eventually lost approx­imately 90,000 l.4-pound coho salmonto this pathogen, primarily in one largenet pen. Shortly after this, some of ourexperimental vaccinated coho were lostdue to infections by this new pathogen.

No further losses to vibriosis occuredwith either our experimental fish orDomsea Farms' until the followingsummer growing season (1974) whennominal losses began to occur in ourvaccinated fish.

Another new aquaculture facility,Pacific Ocean Farms, began growingabout 300,000 coho salmon near ClamBay in June 1974. All of these fish hadbeen individually vaccinated by injec­tion with #775 bacterin at least 2 weeksprior to saltwater entry. Our laboratorybegan to isolate the #1669 vibrio fromthese fish in August; the incidence in­creased as the agglutination titer to the#775 organism decreased. The lossescontinued at a low level until watertemperatures dropped below 9°C. Totallosses for the production season were

VACCINAnON PROCEDURESAND RESULTS

Preliminary studies indicated that asingle injection of 2-4 mg of killed,wet-packed cells in physiological salinewould be sufficient to protect cohosalmon against the usual epizootics ofvibriosis occurring in the central regionof the Puget Sound area.

In the spring of 1973, the majority ofexperimental fish in the saltwater pensat Clam Bay were vaccinated intra­peritoneally with heat-killed bacterinprepared from a V. anguillarum or­ganism (Manchester isolate #775) thathad been isolated regularly during theearlier net-pen experiments. Maximumagglutination titers of I:32 were usuallyattained by 30 days postvaccination anddeclined over a 3-month period. Appar­ently, continued exposure to vibriodisease did not result in an anamnesticresponse in vaccinated fish. ByNovember 1973, cumulative mor-

outbreaks. After this pilot projectproved successful in 1972, the UnionCarbide Corporation decided to enterthe salmon aquaculture business asDomsea Farms, Inc., and NMFS con­tinued its research at the Manchesterstation.

I Reference to trade names or commercial firmsdoes not imply endorsement by the NationalMarine Fisheries Service, NOAA. .

VIBRIOSIS INPEN-REARED SALMON

During the past 5 years the NationalMarine Fisheries Service (NMFS) hasbeen rearing salmon and trout in saltwa­ter at the NMFS Aquaculture Experi­ment Station on Puget Sound's ClamBay near Manchester, Wash. (Nov­otny, 1975). It was obvious from thebeginning that some form of preventivemedicine other then chemotherapy wasneeded if the husbandry experimenta­tion was to be succeSsful. Vibriosis, thecommon fish disease caused by themarine pathogen Vibrio anguillarum,can cause high mortality among salmonin saltwater pens, particularly duringthe warmer summer months whenwater temperatures approach 15°C, andpopulations of fish in the pens are high.

A joint experimental pilot farm oper­ated by the Union Carbide Corporation!and NMFS in 1971 involved experi­mental rearing of large numbers of cohosalmon, Oncorhynchus kisutch, insaltwater pens. The results of this ex­periment clearly indicated that antibio­tics were needed during vibrio disease

24 Marine Fisheries Review

Figure I.-Mortality of young-of-the-year(O-age) sockeye salmon smolts injected with#775 V. anguillarum vaccine. The fish weretransferred from fresh water to net pens in thesea on 1 August 1974.

not substantial, even though another, asyet unidenti fied and unrelated, gallbladder lesion occurred in many of thefish.

On 1 August 1974, we transferred450 sockeye salmon, O. nerka, smoltsto saltwater net pens in Clam Bay. Onepen contained 150 nonvaccinated con­trol fish. Two pens contained equal lotsof sockeye vaccinated with a heat­killed vibrio bacterin (isolate #775).Ninety-eight percent of the nonvacci­nated sockeye died within the first 50days, and only the #1669 type vibriowas isolated. Losses in the two vacci­nated lots of fish were minimal at a total

UNVACCINATED

VACCINATED,.

F'~;~CINATED.::'.-:.:-:..,.----

LITERATURE CITEDHarrell, L. W., A. J. Novotny, M. H. Schiewe,

and H. O. Hodgins. 1976. Isolation and de­scription of two vibrios pathogenic to Pacificsalmon in Puget Sound, Washington. Fish.Bull .• U.S. 74:447-449.

Mahnken, C. V. W. 1975. Status report: Com­mercical salmon culture in Puget Sound.Commer. Fish Farmer Aquaculture News2(1):8-9,11.

Novotny, A. J. 1975. Net-pen culture of Pacificsalmon in marine waters. Mar. Fish. Rev.37( I):36-47.

(commercial) and federally fundedlaboratories (D. F. Amend, pers. com­mun.).

During the summer of 1975 re­searchers at the Manchester stationtested bivalent vibrio vaccines in fieldsituations in cooperation with theWashington Department of Fisheries.The efficacy of several adjuvant prep­arations for injection with bacterins wasalso under investigation.

MFR Paper 7297. From Marine Fisheries Review, Vol. 40, No.3, March 7978.Copies of this paper, in limited numbers, are available from D822, User Ser­vices Branch, Environmental Science Information Center, NOAA, Rockville,MD 20852. Copies of Marine Fisheries Review are available from the Superin­tendent of Documents, U.S. Government Printing Office, Washington, DC20402 for $7.70 each.

of 32 fish (see Fig. I), primarily due to#1669 type vibrio.

Serological studies with the two vib­rio isolates and field observations of thethree epizootics caused by the # 1669type organism led us to infer that therewas some cross-protection with the#775 bacterin (Harrell et aI, 1976).

There are now five aquaculturefacilities in Puget Sound that are raisingsalmon in net pens (Mahnken, 1975).Estimated production for 1975 is 350metric tons, of which about one-halfwill have been individually inoculatedby injection with a bivalent #775-1669vaccine. The remainder of the produc­tion will be receiving oral vaccinesand/or chemotherapy as needed.

FUTURE DEVELOPMENTS

A new method of immunizing fishagainst vibriosis by immersion is cur­rently under investigation by private

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