More than for any other species of fish, there have been special laws made for the wild Atlantic salmon. It still holds that special place in our culture that echoes back through centuries, and even through millenia.
- As you can see Salmon has had a mixed history, being originally a common food, then a luxury item and back again. More recently, declining stocks of wild Atlantic Salmon positioned the fish as a luxury food associated only with a special occasion and dinner party entertaining.
Salmon are native to the world’s two biggest oceans and the rivers draining into them. The Atlantic Ocean has only one species
- Atlantic salmon (Salmo salar)
While in the Pacific Ocean there are several species:
- pink salmon (Oncorhynchus gorbuscha)
- chum (O. keta)
- sockeye (O. nerka)
- coho (O. kisutch)
- chinook (O. tschawytscha)
- amago (O. rhodurus)
Known as the ‘King of Fish’, wild salmon has a flesh that is firm, meaty and reddish in colour thanks to the pigment in its natural diet of insects, sand eels, capelin, herring and crustaceans.
Life Cycle of Atlantic Salmon
Wild Atlantic salmon vary in appearance during their lifetime. Until the early 19th century the life cycle was not understood and documented, and Parr and Smolt were assumed to be different species of fish.
Irish salmon are Atlantic salmon, spend their juvenile phase in rivers before migrating to sea to grow. To complete their life cycle they must return to their river of origin to spawn. Fish with this life cycle are called anadromous.
All salmon spawn naturally in freshwater. Spawning typically occurs in the headwater and tributary streams of rivers, though it can happen anywhere in a river if the substrate is suitable. The migration to suitable habitat may commence up to a year before spawning takes place in autumn-winter, salmon ceasing to feed, directing all their energy instead to reproduction.
Usually the female salmon will excavate a depression in the gravel with her tail, and deposit her eggs into this. The nest measures about 10-30cm/4-12″. Even though the nest is little more than a shallow depression, the salmon removes rocks and debris before she lays between 1,500 and 10,000 bright red fish eggs, or roe. The female salmon changes her color during this process and signals her readiness to mate with the male fish that has also migrated back to the stream or river.
The males approach the female as she hovers over her redd and emit their sperm, also known as milt, over the roe. The female fish now uses her dorsal fin to spread some mud and gravel to a depth of several centimetres over the fertilized eggs. The parents then leave the eggs in the nest or “redd”, and there is no further parental care.
The eggs (ova) begin developing right after fertilization, and will hatch after about 180 days at normal water temperatures. The fertilized orange pea-sized eggs will not become “eyed” (i.e., the eyes of the embryo can be seen as two black dots) until January-February, before hatching in March-April.
The just-hatched fish are called alevins, and still have a yolk sac attached to their bodies, with the remains of food supplied from the egg. When most of the their yolk sac has been consumed, the alevins become active and begin their journey up through the gravel. They soon grow all eight fins, which will be used to maintain their position in fast flowing streams and manoeuvre about in the water.
The small fish must rise to the surface of the water to take a gulp of air with which they fill their swim bladder, giving them neutral buoyancy, which makes it easier to swim and hold their position in the water column. This critical period is therefore referred to as “swim-up” and exposes the young to dangerous predators for the first time. Once they begin to swim freely (three to six weeks after hatching), they are called fry. Their survival is temperature dependant and heavily influenced by predation and competition for food.
Fry quickly develop into parr with vertical stripes and spots for camouflage. They feed on aquatic insects and grow for one to three years in their natal stream. Once the parr have grown to 10–24 cm in body length, they undergo a physiological pre-adaptation to life in seawater while still in freshwater, by smolting. In addition to the internal changes in the salt-regulating mechanisms of the body, the appearance and behaviour of the fish also change. The smolts become silvery and change from swimming against the current to moving with it. This adaptation prepares the smolt for its journey to the oceans.
In spring, large numbers of smolts leave Irish rivers to migrate north along the slope current into the rich feeding grounds of the Norwegian Sea and the greater expanse of the North Atlantic Ocean. Here they feed primarily on fish (piscivorous), such as capelin (Mallotus villosus), herring (Alosa spp.), and sand eel (Ammodytes spp.). As they grow, fewer predators are able to feed on them. Their rate of growth is therefore critical to survival.
Most of these salmon migrate to feeding areas off Greenland, whilst some may remain in coastal waters within the influence of the rivers in which they were born. Some Irish salmon, called grilse will reach maturity after one year at sea and return to their river in summertime weighing from 1 to 4kg. If it takes two or more years to mature, the salmon will return considerably earlier in the year and larger at 3 to 15kg – becoming a highly prized fish but also a very rare one. Salmon exhibit a remarkable “homing instinct”, by which a very high proportion are able to locate their river of origin using the earth’s magnetic field, the chemical smell of their river and pheromones (chemical substances released by other salmon in the river). A journey of up to 5000km makes salmon “the king of fish”.
- Some stay at sea longer and these are the big fish that can weigh up to 43 lbs (our company record) or more. Summer catch rates for fish in the wild are very low, but sufficient to sustain the population if not over harvested. To conserve stocks, Irish Salmon is only fished in June and July each year. We purchase our Wild fish for the year during this season and clean, freeze and store them until we receive orders. They are then smoked and shipped to our customers.
Having spawned, the salmon are referred to as “kelts”. Weakened by not having eaten any food since their arrival in freshwater and losing energy in a bid to reproduce successfully they are susceptible to disease and predators. Mortality after spawning can be significant, especially for males but some do survive and commence their epic journey again. In exceptional cases, some Irish salmon are known to have spawned up to three times!
Wild Atlantic Salmon, offers the ultimate gourmet experience and is now an extremely limited resource.
Draft Net Fishing The Killary, Co. Galway.
Thanks to the Galway Marine Institute & Atlantic Salmon Federation