Albury Estate – Trout information
Trout is the name for a number of species of freshwater fish belonging to the genera Oncorhynchus, Salmo and Salvelinus, all of the subfamily Salmoninae of the family Salmonidae.
The word trout is also used as part of the name of some non-salmonid fish such as Cynoscion nebulosus, the spotted seatrout or speckled trout.
Most trout such as Lake trout live in freshwater lakes and/or rivers exclusively, while there are others such as the Rainbow trout which spend two or three years at sea before returning to freshwater to spawn, a habit more typical of salmon.
The Albury Estate stocks Rainbow Trout with Brown Trout at certain times of the year. All fish are reared at the Albury Estate Fish Farm.
Trout that live in different environments can have dramatically different colorations and patterns. Mostly, these colours and patterns form as camouflage, based on the surroundings, and will change as the fish moves to different habitats. Trout in, or newly returned from the sea, can look very silvery, while the same fish living in a small stream or in an alpine lake could have pronounced markings and more vivid coloration; it is also possible that in some species this signifies that they are ready to mate. It is virtually impossible to define a particular colour pattern as belonging to a specific breed; however, in general, wild fish are claimed to have more vivid colours and patterns.
Trout have fins entirely without spines, and all of them have a small adipose fin along the back, near the tail. The pelvic fins sit well back on the body, on each side of the anus. The swim bladder is connected to the esophagus, allowing for gulping or rapid expulsion of air, a condition known as physostome. Unlike many other physostome fish, the trout do not use their bladder as an auxiliary device for oxygen uptake, relying solely on their gills.
There are many species, and even more populations that are isolated from each other and morphologically different. However, since many of these distinct populations show no significant genetic differences, what may appear to be a large number of species is considered a much smaller number of distinct species by most ichthyologists. The trout found in the eastern United States are a good example of this. The brook trout, the aurora trout, and the (extinct) silver trout all have physical characteristics and colorations that distinguish them, yet genetic analysis shows that they are one species, Salvelinus fontinalis.
Trout are usually found in cool (50–60 °F, 10–16 °C), clear streams and lakes, although many of the species have anadromous strains as well. Young trout are referred to as troutlet, troutling or fry. They are distributed naturally throughout North America, northern Asia and Europe. Several species of trout were introduced to Australia and New Zealand by amateur fishing enthusiasts in the 19th century, effectively displacing and endangering several upland native fish species. The introduced species included brown trout from England and rainbow trout from California.
The rainbow trout (Oncorhynchus mykiss) is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea-run rainbow trout (anadromous) usually returning to freshwater to spawn after two to three years at sea; rainbow trout and steelhead trout are the same species. The fish are often called salmon trout. Several other fish in the salmonid family are called trout; some are anadromous like salmon, whereas others are resident in freshwater only.
The species has been introduced for food or sport to at least 45 countries, and every continent except Antarctica. In some locations, such as Southern Europe, Australia and South America, they have negatively impacted upland native fish species, either by eating them, outcompeting them or transmitting contagious diseases.
Rainbow trout are predators with a varied diet, and will eat nearly anything they can grab. Their image as selective eaters is only a legend. Rainbows are not quite as piscivorous or aggressive as brown trout or lake trout (char). Young rainbows survive on insects, fish eggs, and smaller fish (up to 1/3 of their length), along with crayfish and other crustaceans. As they grow, though, the proportion of fish increases in most all populations. Some lake-dwelling lines may become planktonicfeeders. While in flowing waters populated with salmonids, trout eat varied fish eggs, including salmon and cutthroat trout, as well as the eggs of other rainbow trout, alevin, fry, smolt and even leftover carcasses.
Rainbow trout and steelhead are both highly desired food and sportfish. A number of angling methods are common. Rainbow trout are a popular target for fly fishers.
The IGFA recognizes the world record for rainbow trout was caught on Saskatchewan’s Lake Diefenbaker by Sean Konrad on September 5, 2009. The fish weighed 48 lb, 0 oz (21.77 kg). Many anglers consider the Rainbow trout the hardest fighting trout species, as this fish is known for leaping when hooked and putting a powerful fight.
Rainbow trout is popular in Western cuisine, and is caught wild and farmed. It has tender flesh and a mild, somewhat nutty flavour. However, farmed trout and those taken from certain lakes have a pronounced earthy flavour which many people find unappealing; many shoppers, therefore, ascertain the source of the fish before buying. Wild rainbow trout that eat scuds (freshwater shrimp), insects such as flies, and crayfish are the most appealing. Dark red/orange meat indicates it is either an anadromous steelhead or a farmed rainbow trout given a supplemental diet with a high astaxanthin content. The resulting pink flesh is marketed under monikers such as Ruby Red or Carolina Red.
Steelhead meat is pink like that of salmon, and is more flavourful than the light-coloured meat of rainbow trout.
The brown trout (Salmo trutta) is an originally European species of salmonid fish. It includes both purely freshwater populations, referred to Salmo trutta and anadromous forms known as the sea trout, trutta.The latter migrates to the oceans for much of its life and returns to freshwater only to spawn. Sea trout in the UK and Ireland have many regional names, including sewin (Wales), finnock (Scotland), peal (West Country), mort (North West England) and white trout (Ireland).
The brown trout is normally considered to be native to Europe and Asia,
The fish is not considered to be endangered, although, in some cases, individual stocks are under various degrees of stress mainly through habitat degradation, overharvest and artificial propagation leading to introgression. Increased frequency of excessively warm water temperatures in high summer causes a reduction in dissolved oxygen levels which can cause ‘summer kills’ of local populations if temperatures remain high for sufficient duration and deeper/cooler or fast, turbulent moreoxygenated water is not accessible to the fish. This phenomenon can be further exacerbated by eutrophication of rivers due to pollution – often from the use of agricultural fertilizers within the drainage basin.
In small streams, brown trout are important predators of macroinvertebrates, and declining brown trout populations in these specific areas would affect the entire aquatic food web. Trutta morpha fario prefers cold (though in comparison with other “trout”, this species has a somewhat higher temperature preference of about 60-65°F, or 15.5-18.3°C), and well-oxygenated upland waters, especially large streams in mountainous areas.
Cover or structure is important to trout, and they are more likely to be found near submerged rocks, undercut banks, and overhanging vegetation. Structure provides protection from predators, bright sunlight, and associated high water temperatures. Access to deep water for protection in winter freezes, or fast water for protection from low oxygen levels in summer are also ideal.
The brown trout is a medium-sized fish, growing to 20 kg or more in some localities, although in many smaller rivers, a mature weight of 1 kg (2 lb) or less is common. The spawning behaviour of brown trout is similar to that of the closely related Atlantic salmon. A typical female produces about 2,000 eggs per kilogram (900 eggs per pound) of body weight at spawning. On Sept. 11, 2009, a 41.45-lb (18.80-kg) brown trout was caught by Tom Healy in the Manistee River system in Michigan, setting a new state record. As of late December 2009, the fish captured by Mr. Healy was confirmed by both the International Game Fish Association and the Fresh Water Fishing Hall of Fame as the new all-tackle world record for the species. This fish now supplants the former world record from the Little Red River in Arkansas.
Brown trout can live to ages of 20 years. Brown trout are active both by day and by night and are opportunistic feeders. While in fresh water, their diets will frequently include invertebrates from the streambed, other fish, frogs, mice, birds, and insects flying near the water’s surface. The high dietary reliance upon insect larvae, pupae, nymphs and adults is what allows trout to be a favoured target for fly fishing. Freshwater brown trout range in colour from largely silver with relatively few spots and a white belly, to the more well-known brassy brown cast fading to creamy white on the fish’s belly, with medium-sized spots surrounded by lighter halos. The more silver forms can be mistaken for rainbow trout.
Young brown trout feed on insects and other invertebrates such as shrimp, caddisflies, stoneflies, and mayflies. Both larvae and adults are taken, and the fish will eat whatever local insect life is abundant at the time. Larger fish are active predators of fish including young brown trout, suckers, sculpins, shad, whitefish and rainbow trout. Larger brown trout will also feed on small terrestrial animals that fall into the water, such as baby birds falling from overhanging nests, or even swimming mice or voles. Brown trout sometimes do not actively feed until the late afternoon or early evening, but when the weather is cool, they will feed during the day, as well. The largest browns feed under cover of darkness. Brown trout can be caught with artificial flies.