By Neil Cameron,
Campbell River Courier-Islander; -With Files From Dfo
December 7, 2012
About 40,000 young coho are getting their flu shot in a trial inoculation for native coho salmon at Quinsam River Salmon Hatchery in Campbell River.
And it could help fisheries managers understand why coho returns have dropped to one per cent of outmigrating salmon from the 10 per cent of the 1980s.
The coho received their injections at the Fisheries and Oceans Quinsam Hatchery in Campbell River in hopes of improving their survival rate in the Salish Sea (Strait of Georgia). The inoculation is for vibriosis a pathogen that researchers believe is especially prevalent in the spring when the young coho are released into the wild. It is thought that the higher than average spring water temperatures that are occurring from climate change, makes the disease more prevalent in the marine environment, and could be one of the factors that are adversely affecting ocean survival of coho salmon, said Dave Ewart, Watershed Enhancement Manager, Oceans, Habitat and Enhancement Branch, South Coast Area, Quinsam River Hatchery.
“Two years ago we met as a group including our Fisheries support and assessment biologists, and veterinarians from DFO and the Centre for Aquatic Health Sciences,” Ewart said. “We were looking at things the hatchery could do as a trial to try and improve coho survival, or at least learn what’s happening to them after we let them go.”
The group was keen at looking at a disease called vibriosis which is a bacterial disease that occurs naturally and is common in the marine environment. It is known to affect juvenile salmon in the early marine phase of their lives, and is triggered in the spring by warmer water. For coho salmon, migration from fresh water to the ocean occurs in May, when normally, temperatures in the estuary and near shore environments are warming.
This ocean entry timing may coincide with conditions that could lead to recently released coho smolts becoming infected.
In aquaculture, vibriosis is known to be a serious concern for juvenile salmon rearing in ocean pens, and for this reason, all smolts are vaccinated against vibrio prior to being put into the ocean.
This vaccination process has been used for years as common practice on salmon farms, and is very successful. For these reasons, a vaccination trial was proposed for Quinsam Hatchery coho.
Salmon enhancement facilities, (including Quinsam), routinely use a vibrio vaccine for chinook salmon smolts as part of sea pen rearing programs in the spring.
However, this is done with a bath solution which is not as effective as an inoculation, and although the incidence of vibrio is controlled for the short rearing duration in the sea pen, it is not known how effective this preventative measure is on larger and older fish.
There is evidence to show that not vaccinating fish in any way and then rearing in the ocean in pens can be very risky for young salmon, and vibrio outbreaks have occurred which cause significant mortality, said Ewart.
In particular, if the spring is warm and water temperatures rise, the conditions for the bacteria are ideal and when young salmon are added, losses may occur.
The aquaculture industry vaccinate all their fish and have a good understanding of how it protects them against disease because they have the fish at hand throughout its life cycle.
“The problem with our hatchery reared salmon, like coho, is we let them go from here and we wave goodbye and we don’t know where the losses occur,” said Ewart. “They’re gone and we wait for two or three years and the survivors come back but we don’t have any way of knowing what kills (the others) out there, other than humans who report their catch and turn in tagged heads.”
The proof in the vibriosis pudding will come as early as 2013. The coho being injected now will be released in May and some will return at jacks (precocious males) in the fall.
Another 40,000 coho will act as the control group. They will be anaesthetized, tagged, and inoculated just like the vaccinated group, only it will be with a placebo, a saline solution. All 80,000 will be released along with the rest of the coho smolts currently being reared at Quinsam (total release will be 650,000 smolts), in May of 2013.
Comparison of the two tag groups at adult return will give some indication how the program worked, said Ewart.
“When those adults and jacks come back into the hatchery, we will look for the tagged fish and sample them for their tags,” said Ewart. “If we find that the vaccinated group has significantly more numbers than the placebo (control) group, then we will have some initial indication that vaccinating coho is worthwhile.
“Injection vaccinating of coho for vibriosis is something that our DFO salmon enhancement program has not tried at a hatchery. This is a first that I’m aware of,” he said.
But as good as the potential of the program is it wouldn’t have happened without the support of Campbell River, one of the other reasons it is known as the Salmon Capital of the World. With budget constraints and the financial ability to do the program found wanting, Ewart said he put the word out in the community and the response was unbelievable.
Stepping forward was the Campbell River Salmon Foundation, who has donated $9,200 in cash. Mike Gage, veteran fund raiser and past chairman of the CRSF, started knocking on doors and received $2,000 from Mercury Marina and Trailer Park, and a $1,000 donation from Marine Harvest Canada which was put towards this project. The Centre for Aquatic Health Sciences is donating the fish health checks of the juveniles before inoculation, at release in the spring, and when the adults return something that’s worth about $8,000.
Novartis donated the vaccine ($700), Northwest Marine Technology donated coded wire tags ($4,000), Syndel labs donated anaesthetic, ($200), and Fisheries & Oceans Canada, (Quinsam Hatchery) is providing in-kind services valued at approximately $8,000.
“It really is a community-based program,” said Ewart. “And it could go a long way to shedding more light on what’s happening out there, finding out another piece to the puzzle.”