Fish Culture

Brood Capture

Quatse River Hatchery enhances five species of Pacific Salmon in four North Island drainages. Quatse staff use a seine net in low river conditions to capture adult salmon in September and October. These brood are truck transported to the hatchery and held in raceways or circular tanks until maturation and spawning.

Broodstock capture takes place in the fall and is generally done with a beach seine

Each stock is genetically unique and must be held separately from one another. Spawn timing varies by stock and species, with Pinks and Chum spawning first from late September to mid-October. Coho are the last to Spawn from late October to early December.

Quatse River Hatchery also enhances winter Steelhead from two North Island rivers, the Quatse and Cluxewe. These Steelhead spawn in the spring, from February to April, and they can survive to spawn over multiple years. Provincial policy mandates the use of wild steelhead for broodstock. These are captured live by volunteer anglers, authorized under brood collection permits. Angled wild steelhead are transported to the hatchery and held untill maturity.

Spawning and Incubation

Salmon spawning occurs over a period of four to six weeks. Captured females are checked weekly to determine maturity. Mature or 'ripe' females are humanely dispatched, while immature females are returned to holding tanks. For genetic representation, the eggs from a single female are fertilized by milt from a single male. The spawned carcasses are returned to the river of origin to provide instream nutrients.

Fertilized eggs are placed into Heath trays (coho, chum, chinook and steelhead) or Pallant boxes (pinks) for incubation. In four to six weeks eggs reach the 'eyed' stage, where the embryo's eye is visible and the eggs can be physically handled and inventoried. In a further four to six weeks, alevin hatch from the eggs. The alevin will absorb their yolk sac over the next four to six weeks. Once the yolk sac is absorbed, the alevin are called fry and are ponded into rearing containers. In nature, this is when the fry emerges from the gravel streambed.

Juvenile Rearing

Fry rearing strategies vary with species. Pink salmon have no freshwater residency so they are released immediately upon emergence from Pallant boxes. Efforts are made to release these fry at dusk to avoid predation by birds and other fish. Chum also have no freshwater residency, however studies have shown increased survival rates by rearing them from their 0.4g emergence weight to a release weight of about 1.0g. Our Quatse chum are held at the hatchery and fed for about four weeks in order to attain this weight.

For coho, chinook and steelhead, juvenile rearing is essentially the same, except for duration and release size targets. Fry are ponded into rearing containers where they are initiated on feed. Hatchery chinook are reared for three months, targeting 5g smolt release in June.

Coho are ponded in February and March, while spring spawning steelhead are ponded in June. Both are reared over the summer at the Quatse hatchery. In order to achieve production targets, our coho and steelhead fry are transported to the O'Connor Lake net pen facility in early September. This offers increased juvenile rearing capacity while the hatchery is used for adult brood holding during the fall spawning season. The coho smolt target size is 25g, while the steelhead smolt target size is 80g. Both are released in May to their streams of origin, mimicking natural North Island smolt migration timing.

The coho release size is significantly smaller than that of the steelhead in order to reduce the incidence of coho jacks. Steelhead do not have the jacking trait and studies have shown survival benefits from larger release sizes. All of NVISEA's coho smolt and steelhead production is adipose clipped for hatchery origin identification. This allows angler retention of the hatchery produced fish, and allows identification of the hatchery contribution to the return.

Transport and Release

Quatse crew member releasing smolts

NVISEA utilizes two one-ton flat-deck trucks with aluminium 1,250 litre transport tanks. Both trucks are equipped with oxygen tanks for aeration during transport. These trucks are used for adult brood transport from the river to the hatchery, juvenile transport from the hatchery to O'Connor Lake net pens and for juvenile release.

Fry releases are dipnetted from the transport tank into 20 litre buckets and then scatter-planted throughout the watershed. For smolt releases, a 6" discharge valve on the transport tank is fitted with a 50' hose. The entire tank of fish is flush-released into a single location.