Australian salmon
Encyclopedia
Australian Salmon, are medium-sized perciform marine fish
of the small family
Arripidae (sometimes incorrectly spelled Arripididae). Four species
are recognized, all within the genus
Arripis. Despite the common name
, Australian Salmon are not related to the salmon
(Salmonidae
) of the Northern Hemisphere
; the former were named so by early Europe
an settlers after their superficial resemblance to the salmoniform fishes.
Relatively long-lived fish, Australian Salmon are a favored target of recreational fishers, and both commercial and traditional Māori fisheries
. They are also common bycatch
of the Australasian Snapper
(Pagrus auratus), mullet
(Mugilidae), White Trevally
(Pseudocaranx dentex), and mackerel
(Scombridae) fisheries. These species are all taken in great numbers by way of purse seine nets and trawling. They are also caught by skilled fishermen along the southern coastline of Australia by beach seining. Due to declining numbers and ever-increasing annual catch sizes, the future viability of the Australian Salmon stock has been put into question.
originates behind the pectoral fins, the former being confluent with, but noticeably higher than the much longer soft dorsal fin (with 15 - 19 rays), itself much longer than the anal fin (which has three spines and 9 - 10 soft rays). The pelvic fin is situated in a thoracic position.
Scale
s and eye
s are relatively large - in the Australian Herring, the eyes are approximately one fifth the length of the head in diameter. The large mouth is terminal, and the jaws are lined with bands of sharp villiform (brushlike) teeth
. The lateral line
runs along the upper sides of the body.
The Western Australian Salmon, is the largest species at a maximum 96 cm (three feet) standard length (that is, excluding the caudal fin) and 10.5 kg in weight. The Australian Herring is the smallest species at maximum 41 cm (16 inches) fork length (that is, from the snout to the middle of the caudal fin's fork) and 800 g. Australian Salmon share a passing resemblance to the unrelated yellowtail amberjack
, (Seriola lalandi), locally known as "kingfish", with which larger Australian Salmon are sometimes confused.
All species are strongly countershaded
; dorsal colours range from dark blue-green in A. trutta, green in A. georgianus, and steel-blue to grayish- or greenish-black in A. truttaceus; the colours fade to a silver-white ventrally. A smattering of yellow, gray, or blackish spots embellishes the dorsal half, the spots arranged vertically or longitudinally in a series of rows. There are marked differences in subadult coloration: for example, on the flanks of juvenile Australian Herring are a series of dark golden vertical bars.
in open water during the austral spring, releasing a large number of tiny (1 mm in diameter), smooth spherical eggs
made buoyant by lipid
droplets. The eggs (and later the larva
e), which possess an unsegmented yolk, become part of the zooplankton
, drifting at the mercy of the currents until the larvae develop and settle. The young Australian Salmon then spend the first 2 - 5 years in sheltered coastal bays, inlets, and estuaries until they become sexually mature and begin to move into more open waters. Relatively long-lived fishes, Australian Salmon may attain an age of 26 years in Arripis trutta and 7 - 9 years in other species.
All species are oceanic spawners. Reports of A. trutta being anadromous and spawning in freshwater are not correct; this may be due to confusion with sea run specimens of exotic Brown Trout
, (Salmo trutta), or anadromous populations of native Spotted Galaxias
, (Galaxias truttaceus).
Arripis georgianus are thought - due to females retaining both ripe and unripe eggs - to be "partial spawners"; that is, they may spawn over a long period with no real peaks. In contrast, A. trutta and A. truttaceus are thought to be "serial batch spawners", completing their spawning season after a series of small "burst" spawnings.
and epipelagic, staying within the upper layers of relatively shallow (from 1 - 80 metres), open and clear coastal waters (although the Western Australian Salmon may prefer deeper water). The turbulent surf zone
of beach
es, rocky reef
s, bays, and brackish waters such as estuaries
are also frequented, and some species may also enter river
s. Juveniles inhabit estuaries and mangrove
s, as well as sheltered bays with soft bottoms carpeted with seagrass
. Adults undertake seasonal migrations over vast distances, moving into deeper water during winter months.
Australian Salmon form immense schools with hundreds to thousands of individuals, as both adults and juveniles. They are carnivorous
and feed primarily on small fish such as pilchard (Clupeidae); crustacean
s such as krill
(Euphausiacea), copepod
s, and other zooplankton
(the latter comprising the bulk of the juvenile diet). The zoobenthos
is also sampled to some extent, with primarily shellfish
, crab
s, and annelid
worms eaten. The Australian Salmon are very fast swimmers, and are sometimes seen mingling with ostensibly similar species of carangid
s, such as trevally; this is an example of mutualism.
Together with the carangids, Australian Salmon feed en masse by co-operatively bullying baitfish up to the surface; this herding technique is exploited by seabird
s which are quickly attracted to, and feed upon, the foaming mass of fish at the surface. This commensal
relationship between the Australian Salmon and the birds is noted to be especially strong in such species as the White-fronted Tern
, (Sterna striata), Fluttering Shearwater
, (Puffinus gavia), and Buller's Shearwater
, (Puffinus bulleri). The baitfish made available by the Australian Salmon's herding behaviour may also be important to the reproductive success of winter-nesting birds; the decline of the Australian Salmon stocks has evoked concern for these bird species, some of which - such as the Fairy Tern
, (Sterna nereis), - are endangered
http://www.option4.co.nz/Fisheries_Mgmt/kahl_mcu.htm.
Aside from seabirds, the Australian Salmon are also important in the diets of cetaceans such as Orca
(Orcinus orca) and Bottlenose Dolphin
s (Tursiops truncatus & T. aduncus); several species of large shark
s, for example; Great White
(Carcharodon carcharias), Dusky
(Carcharhinus obscurus), Copper (Carcharhinus brachyurus), and Sand Tiger (Carcharias taurus) Sharks; and eared seal
s such as the Australian Sea Lion
(Neophoca cinerea).
(Palinuridae) traps and other commercial and recreational fishing. The Australian Salmon fetch no more than a few dollars (AU) per kilogram; nonetheless, large numbers are taken via purse seine nets (and to a lesser extent trawling, hauling, gill, and trap nets) annually; the reported 2002 - 2003 commercial New Zealand catch of 'Kahawai' was 2,900 tonne
s http://www.nzherald.co.nz/sports/sportsstorydisplay.cfm?storyID=3600640&thesection=sport&thesubsection=othersports&thesecondsubsection=general. Such reported catches do not include the untold tonnes taken as bycatch from operations targeting more highly valued species. Low-flying planes are used to locate and target sizeable Australian Salmon schools, and critics have cited this practice as a means by the industry to artificially inflate catch records (which would give a false impression of abundance). Australian Salmon numbers have declined noticeably however, with large specimens becoming ever rarer; the fish have all but disappeared from some areas. It was not until October 1, 2004 that the New Zealand Ministry of Fisheries included 'Kahawai' under its Quota Management System
, setting a catch limit of 3,035 tonnes for the season. This was a five percent increase over the previous two years, despite the government's intention of lowering catch limits.
In New Zealand, Australian Salmon and in particular Northern Kahawai are highly regarded for their flesh when hot smoked by recreational fisherman, usually using Manuka sawdust or woodchips. Australian Salmon prepared in this manner are available in many New Zealand supermarkets and fishmongers. The flesh is usually eaten hot, or broken up and used in fish pie.
The Māori of New Zealand, to whom the fish are known by their name Kahawai, koopuuhuri and kooukauka, http://www.forestandbird.org.nz/bestfishguide/species/kahawai.asp fish in subsistence and customary capacities. The fish were (and are) caught with lines of flax fibre and elaborate hook
s of bone
, wood
, shell such as paua
, or stone
. The fish are filleted before being hung on racks to dry. Recreational fishers also seek Australian Salmon for their renowned mettle when hooked; the fish are a challenge to land and often jump, occasionally standing on their tails. A significant number are taken for sport. No records of total recreational catches are kept, but the year's estimated catch of Australian Herring from Western Australia's Blackwood River
estuary beginning May, 1974 was 68,000 individualshttp://adl.brs.gov.au/fishstats/atlas/37344001.cfm.
Commercial fishing practices undertaken across Australia and New Zealand have been highly criticised in various recreational fishing magazines as being excessive. Many high profile anglers such as those on Fishing WA have made statements that the commercial fish catch in Western Australia and Australia in general is beyond the scope necessary for human and animal consumption, and that they are far more valuable as a recreational fish species. The ease of catching Australian Salmon, which tend to form schools of several tonnes, has meant that recreational fishers are finding fewer of these species in inshore waters during season (the migration patterns of Australian Salmon mean they come into warmer waters during the Autumn).
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
of the small family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Arripidae (sometimes incorrectly spelled Arripididae). Four species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
are recognized, all within the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Arripis. Despite the common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
, Australian Salmon are not related to the salmon
Salmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...
(Salmonidae
Salmonidae
Salmonidae is a family of ray-finned fish, the only living family currently placed in the order Salmoniformes. It includes salmon, trout, chars, freshwater whitefishes and graylings...
) of the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
; the former were named so by early Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an settlers after their superficial resemblance to the salmoniform fishes.
Relatively long-lived fish, Australian Salmon are a favored target of recreational fishers, and both commercial and traditional Māori fisheries
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
. They are also common bycatch
Bycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
of the Australasian Snapper
Australasian snapper
The Australasian snapper or Pagrus auratus is a species of porgie found in coastal waters of New Zealand and Australia. Although it is almost universally known in these countries as snapper it does not belong to the Lutjanidae family...
(Pagrus auratus), mullet
Mullet (fish)
The mullets or grey mullets are a family and order of ray-finned fish found worldwide in coastal temperate and tropical waters, and in some species in fresh water. Mullets have served as an important source of food in Mediterranean Europe since Roman times...
(Mugilidae), White Trevally
White trevally
White trevally, Pseudocaranx dentex, is a jack of the family Carangidae widespread in tropical and warm temperate areas between 40°N and 47°S, in the Atlantic, Mediterranean, Indian and Pacific Oceans. It has a deep body, and a greenish colour with metallic overtones and a dark spot above the...
(Pseudocaranx dentex), and mackerel
Mackerel
Mackerel is a common name applied to a number of different species of fish, mostly, but not exclusively, from the family Scombridae. They may be found in all tropical and temperate seas. Most live offshore in the oceanic environment but a few, like the Spanish mackerel , enter bays and can be...
(Scombridae) fisheries. These species are all taken in great numbers by way of purse seine nets and trawling. They are also caught by skilled fishermen along the southern coastline of Australia by beach seining. Due to declining numbers and ever-increasing annual catch sizes, the future viability of the Australian Salmon stock has been put into question.
Species and range
The ranges of the four species may overlap to some extent, but can be described thus:- Australian HerringAustralian herringThe Australian Herring, Arripis georgianus, is one of four species within the Arripis genus. It closely resembles its 'cousins', the Australian Salmon, although it grows to a smaller size. Like the other members of its genus, it is found in cooler waters around the southern coast of Australia...
(Also known as Australian Ruff or Tommy Ruff), Arripis georgianus: GippslandGippslandGippsland is a large rural region in Victoria, Australia. It begins immediately east of the suburbs of Melbourne and stretches to the New South Wales border, lying between the Great Dividing Range to the north and Bass Strait to the south...
Lakes, Victoria to Shark BayShark BayShark Bay is a World Heritage listed bay in Western Australia. The term may also refer to:* the locality of Shark Bay, now known as Denham* Shark Bay Marine Park* Shark Bay , a shark exhibit at Sea World, Gold Coast, Australia* Shire of Shark Bay...
, Western AustraliaWestern AustraliaWestern Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
; endemicEndemic (ecology)Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the... - Eastern Australian SalmonEastern Australian salmonThe Eastern Australian Salmon, Arripis trutta, known as Kahawai in New Zealand, is one of four species within the Arripis genus, found in cooler waters around the south eastern coast of Australia and New Zealand. Although it is referred to as a salmon in Australia, it is not related to any species...
, Arripis trutta: From western Victoria to New Zealand, including the islands of TasmaniaTasmaniaTasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
, Lord HoweLord Howe IslandLord Howe Island is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, directly east of mainland Port Macquarie, and about from Norfolk Island. The island is about 11 km long and between 2.8 km and 0.6 km wide with an area of...
, and NorfolkNorfolk IslandNorfolk Island is a small island in the Pacific Ocean located between Australia, New Zealand and New Caledonia. The island is part of the Commonwealth of Australia, but it enjoys a large degree of self-governance... - Western Australian Salmon, Arripis truttaceus: Western Australia to Victoria and Tasmania
- Northern Kahawai (Also known as Giant or Kermadec Kahawai), Arripis xylabion: New Zealand, west to Lord Howe, Norfolk and Kermadec IslandsKermadec IslandsThe Kermadec Islands are a subtropical island arc in the South Pacific Ocean northeast of New Zealand's North Island, and a similar distance southwest of Tonga...
Physical description
A streamlined, fusiform body and large, powerful forked tail - the upper lobe of which is equal to or less than the length of the head in the Eastern Australian Salmon - are indications of the fast-paced pelagic lives these fish lead. Upon dissection, the extremely large, dense gills (for maximum oxygen extraction) and large proportion of red aerobic muscle in the 'fillets' is further evidence of a fast-paced pelagic life. The first (spinous, with nine spines) dorsal finDorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
originates behind the pectoral fins, the former being confluent with, but noticeably higher than the much longer soft dorsal fin (with 15 - 19 rays), itself much longer than the anal fin (which has three spines and 9 - 10 soft rays). The pelvic fin is situated in a thoracic position.
Scale
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
s and eye
Eye
Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement...
s are relatively large - in the Australian Herring, the eyes are approximately one fifth the length of the head in diameter. The large mouth is terminal, and the jaws are lined with bands of sharp villiform (brushlike) teeth
Tooth
Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...
. The lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
runs along the upper sides of the body.
The Western Australian Salmon, is the largest species at a maximum 96 cm (three feet) standard length (that is, excluding the caudal fin) and 10.5 kg in weight. The Australian Herring is the smallest species at maximum 41 cm (16 inches) fork length (that is, from the snout to the middle of the caudal fin's fork) and 800 g. Australian Salmon share a passing resemblance to the unrelated yellowtail amberjack
Yellowtail amberjack
The yellowtail amberjack or great amberjack, Seriola lalandi, is a large fish found in the Pacific and Indian oceans. It can be divided into three sub-species: The California yellowtail, Seriola lalandi dorsalis, the southern yellowtail, or in New Zealand and Australia the yellowtail kingfish or...
, (Seriola lalandi), locally known as "kingfish", with which larger Australian Salmon are sometimes confused.
All species are strongly countershaded
Countershading
Countershading, or Thayer's Law, is a form of camouflage. Countershading, in which an animal’s pigmentation is darker dorsally, is often thought to have an adaptive effect of reducing conspicuous shadows cast on the ventral region of an animal’s body...
; dorsal colours range from dark blue-green in A. trutta, green in A. georgianus, and steel-blue to grayish- or greenish-black in A. truttaceus; the colours fade to a silver-white ventrally. A smattering of yellow, gray, or blackish spots embellishes the dorsal half, the spots arranged vertically or longitudinally in a series of rows. There are marked differences in subadult coloration: for example, on the flanks of juvenile Australian Herring are a series of dark golden vertical bars.
Reproduction
Although their reproduction is poorly studied, Australian Salmon are all known to be "pelagic spawners"; that is, they spawnSpawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
in open water during the austral spring, releasing a large number of tiny (1 mm in diameter), smooth spherical eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
made buoyant by lipid
Lipid
Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...
droplets. The eggs (and later the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e), which possess an unsegmented yolk, become part of the zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
, drifting at the mercy of the currents until the larvae develop and settle. The young Australian Salmon then spend the first 2 - 5 years in sheltered coastal bays, inlets, and estuaries until they become sexually mature and begin to move into more open waters. Relatively long-lived fishes, Australian Salmon may attain an age of 26 years in Arripis trutta and 7 - 9 years in other species.
All species are oceanic spawners. Reports of A. trutta being anadromous and spawning in freshwater are not correct; this may be due to confusion with sea run specimens of exotic Brown Trout
Brown trout
The brown trout and the sea trout are fish of the same species....
, (Salmo trutta), or anadromous populations of native Spotted Galaxias
Spotted galaxias
-Introduction:Spotted galaxias are a largish, primarily-freshwater galaxias species found in southern Australia. Spotted galaxias are perhaps the most beautiful of the Australian galaxias species...
, (Galaxias truttaceus).
Arripis georgianus are thought - due to females retaining both ripe and unripe eggs - to be "partial spawners"; that is, they may spawn over a long period with no real peaks. In contrast, A. trutta and A. truttaceus are thought to be "serial batch spawners", completing their spawning season after a series of small "burst" spawnings.
Ecology
All species are neriticNeritic zone
The neritic zone, also called coastal waters, the coastal ocean or the sublittoral zone, is the part of the ocean extending from the low tide mark to the edge of the continental shelf, with a relatively shallow depth extending to about 200 meters...
and epipelagic, staying within the upper layers of relatively shallow (from 1 - 80 metres), open and clear coastal waters (although the Western Australian Salmon may prefer deeper water). The turbulent surf zone
Surf zone
As ocean surface waves come closer to shore they break, forming the foamy, bubbly surface we call surf. The region of breaking waves defines the surf zone. After breaking in the surf zone, the waves continue to move in, and they run up onto the sloping front of the beach, forming an uprush of...
of beach
Beach
A beach is a geological landform along the shoreline of an ocean, sea, lake or river. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles or cobblestones...
es, rocky reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s, bays, and brackish waters such as estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
are also frequented, and some species may also enter river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
s. Juveniles inhabit estuaries and mangrove
Mangrove
Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly between latitudes N and S...
s, as well as sheltered bays with soft bottoms carpeted with seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
. Adults undertake seasonal migrations over vast distances, moving into deeper water during winter months.
Australian Salmon form immense schools with hundreds to thousands of individuals, as both adults and juveniles. They are carnivorous
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
and feed primarily on small fish such as pilchard (Clupeidae); crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s such as krill
Krill
Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...
(Euphausiacea), copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s, and other zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
(the latter comprising the bulk of the juvenile diet). The zoobenthos
Benthos
Benthos is the community of organisms which live on, in, or near the seabed, also known as the benthic zone. This community lives in or near marine sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths.Many organisms...
is also sampled to some extent, with primarily shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
, crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s, and annelid
Annelid
The annelids , formally called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches...
worms eaten. The Australian Salmon are very fast swimmers, and are sometimes seen mingling with ostensibly similar species of carangid
Carangidae
Carangidae is a family of fish which includes the jacks, pompanos, jack mackerels, and scads.They are marine fish found in the Atlantic, Indian and Pacific Oceans...
s, such as trevally; this is an example of mutualism.
Together with the carangids, Australian Salmon feed en masse by co-operatively bullying baitfish up to the surface; this herding technique is exploited by seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s which are quickly attracted to, and feed upon, the foaming mass of fish at the surface. This commensal
Commensalism
In ecology, commensalism is a class of relationship between two organisms where one organism benefits but the other is neutral...
relationship between the Australian Salmon and the birds is noted to be especially strong in such species as the White-fronted Tern
White-fronted Tern
The White-fronted Tern is the most common tern of New Zealand. It rarely swims, apart from bathing, despite having webbed feet. The species is protected....
, (Sterna striata), Fluttering Shearwater
Fluttering Shearwater
The Fluttering Shearwater is a species of seabird in the Procellariidae family.It is found in New Zealand and Solomon Islands.Its natural habitats are open seas and rocky shores.-References:...
, (Puffinus gavia), and Buller's Shearwater
Buller's Shearwater
Buller's Shearwater is a Pacific species of seabird in the family Procellariidae; it is also known as the Grey-backed Shearwater or New Zealand Shearwater...
, (Puffinus bulleri). The baitfish made available by the Australian Salmon's herding behaviour may also be important to the reproductive success of winter-nesting birds; the decline of the Australian Salmon stocks has evoked concern for these bird species, some of which - such as the Fairy Tern
Fairy Tern
The Fairy Tern is a small tern which occurs in the southwestern Pacific.There are three subspecies:* Australian Fairy Tern, Sterna nereis nereis - breeds in Australia...
, (Sterna nereis), - are endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
http://www.option4.co.nz/Fisheries_Mgmt/kahl_mcu.htm.
Aside from seabirds, the Australian Salmon are also important in the diets of cetaceans such as Orca
Orca
The killer whale , commonly referred to as the orca, and less commonly as the blackfish, is a toothed whale belonging to the oceanic dolphin family. Killer whales are found in all oceans, from the frigid Arctic and Antarctic regions to tropical seas...
(Orcinus orca) and Bottlenose Dolphin
Bottlenose Dolphin
Bottlenose dolphins, the genus Tursiops, are the most common and well-known members of the family Delphinidae, the family of oceanic dolphins. Recent molecular studies show the genus contains two species, the common bottlenose dolphin and the Indo-Pacific bottlenose dolphin , instead of one...
s (Tursiops truncatus & T. aduncus); several species of large shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s, for example; Great White
Great white shark
The great white shark, scientific name Carcharodon carcharias, also known as the great white, white pointer, white shark, or white death, is a large lamniform shark found in coastal surface waters in all major oceans. It is known for its size, with the largest individuals known to have approached...
(Carcharodon carcharias), Dusky
Dusky shark
The dusky shark is a species of requiem shark, family Carcharhinidae, occurring in tropical and warm-temperate continental seas worldwide. A generalist apex predator, the dusky shark can be found from the coast to the outer continental shelf and adjacent pelagic waters, and has been recorded from...
(Carcharhinus obscurus), Copper (Carcharhinus brachyurus), and Sand Tiger (Carcharias taurus) Sharks; and eared seal
Eared Seal
The eared seals or otariids are marine mammals in the family Otariidae, one of three groupings of Pinnipeds. They comprise 16 species in seven genera commonly known either as sea lions or fur seals, distinct from true seals and the Walrus...
s such as the Australian Sea Lion
Australian Sea Lion
The Australian Sea Lion , also known as the Australian Sea-lion or Australian Sealion, is a species of sea lion that breeds only on the south and west coasts of Australia...
(Neophoca cinerea).
Importance to humans
Pungently flavoured, coarse, and slightly oily flesh makes Australian Salmon less desirable as a food fish; it is often sold canned or is smoked to improve its flavour, and bleeding the fish out is also said to help. What is not sold for human consumption is used as bait for rock lobsterRock lobster
Jasus edwardsii, the southern rock lobster, red rock lobster, or spiny rock lobster, is a species of spiny lobster found throughout coastal waters of southern Australia and New Zealand including the Chatham Islands. This species is commonly called crayfish or crays in New Zealand and in Māori...
(Palinuridae) traps and other commercial and recreational fishing. The Australian Salmon fetch no more than a few dollars (AU) per kilogram; nonetheless, large numbers are taken via purse seine nets (and to a lesser extent trawling, hauling, gill, and trap nets) annually; the reported 2002 - 2003 commercial New Zealand catch of 'Kahawai' was 2,900 tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s http://www.nzherald.co.nz/sports/sportsstorydisplay.cfm?storyID=3600640&thesection=sport&thesubsection=othersports&thesecondsubsection=general. Such reported catches do not include the untold tonnes taken as bycatch from operations targeting more highly valued species. Low-flying planes are used to locate and target sizeable Australian Salmon schools, and critics have cited this practice as a means by the industry to artificially inflate catch records (which would give a false impression of abundance). Australian Salmon numbers have declined noticeably however, with large specimens becoming ever rarer; the fish have all but disappeared from some areas. It was not until October 1, 2004 that the New Zealand Ministry of Fisheries included 'Kahawai' under its Quota Management System
Quota Management System
The Quota Management System is a type of individual fishing quota that is used in New Zealand to manage fish stocks.It is the first ever property-based fisheries management system to be implemented.-External links:* – The Quota Management System...
, setting a catch limit of 3,035 tonnes for the season. This was a five percent increase over the previous two years, despite the government's intention of lowering catch limits.
In New Zealand, Australian Salmon and in particular Northern Kahawai are highly regarded for their flesh when hot smoked by recreational fisherman, usually using Manuka sawdust or woodchips. Australian Salmon prepared in this manner are available in many New Zealand supermarkets and fishmongers. The flesh is usually eaten hot, or broken up and used in fish pie.
The Māori of New Zealand, to whom the fish are known by their name Kahawai, koopuuhuri and kooukauka, http://www.forestandbird.org.nz/bestfishguide/species/kahawai.asp fish in subsistence and customary capacities. The fish were (and are) caught with lines of flax fibre and elaborate hook
Fish hook
A fish hook is a device for catching fish either by impaling them in the mouth or, more rarely, by snagging the body of the fish. Fish hooks have been employed for centuries by fishermen to catch fresh and saltwater fish. In 2005, the fish hook was chosen by Forbes as one of the top twenty tools...
s of bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
, wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
, shell such as paua
Abalone
Abalone , from aulón, are small to very large-sized edible sea snails, marine gastropod molluscs in the family Haliotidae and the genus Haliotis...
, or stone
Rock (geology)
In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...
. The fish are filleted before being hung on racks to dry. Recreational fishers also seek Australian Salmon for their renowned mettle when hooked; the fish are a challenge to land and often jump, occasionally standing on their tails. A significant number are taken for sport. No records of total recreational catches are kept, but the year's estimated catch of Australian Herring from Western Australia's Blackwood River
Blackwood River
The Blackwood River is a major river and catchment in the South West of Western Australia.The river begins at the junction of Arthur River and Balgarup River near Quelarup and travels in a south westerly direction through the town of Bridgetown then through Nannup until it discharges into the...
estuary beginning May, 1974 was 68,000 individualshttp://adl.brs.gov.au/fishstats/atlas/37344001.cfm.
Commercial fishing practices undertaken across Australia and New Zealand have been highly criticised in various recreational fishing magazines as being excessive. Many high profile anglers such as those on Fishing WA have made statements that the commercial fish catch in Western Australia and Australia in general is beyond the scope necessary for human and animal consumption, and that they are far more valuable as a recreational fish species. The ease of catching Australian Salmon, which tend to form schools of several tonnes, has meant that recreational fishers are finding fewer of these species in inshore waters during season (the migration patterns of Australian Salmon mean they come into warmer waters during the Autumn).
See also
- List of fish common names
- List of fish families
- Beaked salmon