Commonly Cultured Trout • Rainbow Trout Oncorhynchus mykiss • Brown TroutSalmo trutta • Brook Trout Salvelinus fontinalis
Stages of Culture - Trout • Broodstock • Spawning • Egg incubation • Fry culture • Fingerling production • Growout
Broodstock • Females are 2 to 3 years old • Can be used for more than one year but may have decreased egg quality and quantity • Males are 2 to 3 years old • Can be used several times in one spawning season but not for more than one year
Eggs • “Green eggs” = eggs from 48 hours post-spawn to eyed stage • Can be shipped in plastic eggs at 38°F • Ship eggs wrapped in damp cheese cloth • Chill with ice and let water drip onto eggs
Trout Growout • Raceways • Ponds • Cages Tri-Omega Trout Farm, Pisgah National Forest in Transylvania, NC
Marketing Trout • Fee fishing • Live hauling • Filet products
There are six species of salmon in the Pacific Northwest. The largest salmon, the Chinook, can reach over 6 feet in length and weighs over 100 pounds.
The Salmon Life Cycle In the fall, salmon deposit eggs in the gravel of flowing streams. After spawning (laying eggs), the salmon die sometimes inches from where they were hatched! Amazing instincts! Eggs hatch in the spring, and the alevin grow quickly. Later, the fingerlings continue to grow toward maturity in the streams near their birthplace. As they get closer to their spawning grounds, salmon change in their appearance. Some salmon travel over 1000 miles to lay their eggs. Salmon can grow to be over 100 pounds as they feast in the nutrient- rich waters of the ocean. When full grown, the beautiful, silvery fish begin their migration back to the waters of their birth. When they become strong enough to swim in rushing currents, and quick enough to escape their enemies, the salmon begin migrating to the sea.
Commonly Cultured Salmon • Atlantic Salmon Salmo salar • Chinook Salmon Oncorhynchus tshawytscha • Coho Salmon Oncorhynchus kisutch • Pink SalmonOncorhynchus gorbuscha
Stages of Salmon Culture • Spawning • Egg incubation • Fry culture • Fingerling production • Growout
Alevin Tiny alevin grow quickly after being hatched. When they are as long as your fingernail, they are called fry, and look like real fish! Whey they get to be about as long as your longest finger, they are given a new name -- smolt. As the smolt grow, they eventually begin their migration to the ocean. Smolt Ocean Bound!
Salmon Growout • Extensive • Net Pens Hills Island Salmon Farm, Canada
Salmon - Extensive Culture • Culture fingerlings in tanks • Stock fingerlings (smolts) into native streams • Fish will migrate to the ocean and undergo smoltification • Fish will live in open ocean for approximately 3 years • Fish will return to stream they were planted (chloramine-T, Seattle) • Can be harvested when they return and before they die • Approximately 1 in 1000 return
Salmon Net Pens • Stocking density usually between 8 – 14 kg/cubic meter, but research has shown that 75 kg/cubic meter may be feasible! • Feeding by hand, or electronic (SONAR) • Atlantic salmon represent 80% of net pen operations in the Pacific Northwest and Canada • Atlantic salmon???? • Better FCR, higher survival, better dressout %. • Escapees of Atlantic salmon into Pacific Ocean • A threat to Pacific salmon? • Not yet! Escapees experience high mortality, poor reproduction, do not spawn with Pacific salmon
Figure 1.2.10 Total finfish aquaculture production by major species groups in 2000(values expressed as % by weight) CATFISHES Total production 23,067,973 metric tons & valued at US $ 31,565,104,100 in 2000 FILTER FEEDING CYPRINIDS MARINE FISHES EELS MILKFISH SALMONIDS CATFISH TILAPIA OTHER FRESHWATER FISHES PELLET FEEDING CYPRINIDS
Credits • Pictures and diagrams found in this • photo essay are courtesy of: • The Alaskan Department of Fish and Game • The Washington Department of Fish and Game • The Army Corps of Engineers • The US National Marine Fisheries
These salmon are on their way to the ocean where they may live for 1-5 years, depending on the species, before returning to the rivers and streams to spawn (lay eggs). Only one salmon out of a thousand salmon survives to return to the river to spawn. What are some possible reasons why such a small percentage of salmon actually live long enough to lay eggs?
Going home! These salmon are on their way back to the waters of their birth. Scientists do not know how salmon find the exact location of their birthplace, but their sense of smell (and the chemical signature of the waters) is animportant cue. Along the way are many hazards – some more hungry than others!
Replenishing Nutrients When salmon die after spawning, they provide nutrients to plants and animals near the rivers in which they swam. It has been found that 20 % of the nitrogen (an important element for all living things) in evergreen trees that grow next to salmon spawning waters in Alaska actually was carried upstream with salmon. These nutrients are essentially transported from the ocean to the headwaters by the salmon.