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Forage fish

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Small prey fish
These smallgoldband fusiliers are typical forage fish. They swim in large schools for protection from larger predators.

Forage fish, also calledprey fish orbait fish, are smallpelagic fish that feed onplanktons (i.e.planktivores) and other small aquatic organisms (e.g.krill). They are in turn preyed upon by variouspredators including larger fish,seabirds andmarine mammals, this making themkeystone species in theiraquatic ecosystems.

The typical ocean forage fish feed at the lowertrophic level of thefood chain, often byfilter feeding. They include particularly fishes of the orderClupeiformes (herrings,sardines,shad,hilsa,menhaden,anchovies, andsprats), but also other small fish, includinghalfbeaks,silversides,smelt such ascapelin andgoldband fusiliers.

Forage fish compensate for their small size by formingschools. Some swim in synchronised grids with their mouths open so they can efficiently filter plankton.[1] These schools can become immenseshoals which move along coastlines andmigrate across open oceans. The shoals are concentrated energy resources for the great marine predators. The predators are keenly focused on the shoals, acutely aware of their numbers and whereabouts, and make migrations themselves that can span thousands of miles to connect, or stay connected, with them.[2]

The ocean'sprimary producers, mainly contained inphytoplanktons, producefood energy andbiomassphotosynthetically fromsunlight and are the raw fuel for the oceanfood webs. Forage fish transfer this energy by eating the plankton and becoming food themselves for the top predators. In this way, forage fish occupy the lower-central positions in ocean and lake food webs.[3]

Thefishing industry sometimes catch forage fish forcommercial purposes (i.e. asseafood), but primarily for use asfeeder fish to raise more valuable piscivorous animals (e.g.salmon farms). Somefisheries scientists are expressing concern that this will affect the populations ofpredator fish that depend on them.[4] The practice of harvesting forage fish can also be a sign ofoverfishing asfish stocks of larger species in the fisheries are depleted thus forcing the industry to startfishing down the food web.

In the oceans

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Typical ocean forage fish are small, silvery schoolingoily fish such asherring,anchovies andmenhaden, and other small, schoolingbaitfish likecapelin,smelts,sand lance,halfbeaks,pollock,butterfish and juvenilerockfish. Herrings are a preeminent forage fish, often marketed assardines orpilchards.

The term "forage fish" is a term used infisheries, and is applied also to forage species that are nottrue fish but play a significant role as prey for predators. Thus invertebrates such assquid andshrimp are also referred to as "forage fish". Even the tiny shrimp-like creatures calledkrill, small enough to be eaten by other forage fish, yet large enough to eat the samezooplankton as forage fish, are often classified as "forage fish".[5]

Ocean forage fish
AnchoviesCaribbean reef squidMenhaden
SardinesShrimpNorthern krill

Forage fish utilise the biomass ofcopepods,mysids andkrill in thepelagic zone to become the dominant converters of the enormous ocean production of zooplankton. They are, in turn, central prey items for highertrophic levels. Forage fish may have achieved their dominance because of the way they live in huge, and often extremely fast cruising schools.

Though forage fish are abundant, there are relatively few species. There are more species of primary producers andapex predators in the ocean than there are forage fish.[2]

Ocean food webs

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Main article:Marine food web

Forage fish occupy central positions in the oceanfood webs. The position that a fish occupies in a food web is called itstrophic level (Greektrophē = food). The organisms it eats are at a lower trophic level, and the organisms that eat it are at a higher trophic level. Forage fish occupy middle levels in the food web, serving as a dominant prey to higher level fish, seabirds and mammals.

Ecological pyramids are graphical representations, along the lines of the diagram at the right, which show howbiomass orproductivity changes at each trophic level in anecosystem. The first or bottom level is occupied byprimary producers orautotrophs (Greekautos = self andtrophe = food). These are the names given to organisms that do not feed on other organisms, but produce biomass from inorganic compounds, mostly by aprocess ofphotosynthesis.

In oceans, most primary production is performed byalgae. This is a contrast to land, where most primary production is performed byvascular plants. Algae ranges from single floating cells to attachedseaweeds, while vascular plants are represented in the ocean by groups such as theseagrasses. Larger producers, such as seagrasses and seaweeds, are mostly confined to thelittoral zone and shallow waters, where theyattach to the underlying substrate and are still within thephotic zone. Most primary production in the ocean is performed bymicroscopic organisms, the phytoplankton.

Thus, in ocean environments, the first bottom trophic level is occupied principally byphytoplankton, microscopic drifting organisms, mostlyone-celledalgae, that float in the sea. Most phytoplankton are too small to be seen individually with theunaided eye. They can appear as a green discoloration of the water when they are present in high enough numbers. Since they increase their biomass mostly through photosynthesis they live in the sun-lit surface layer (euphotic zone) of the sea.

Phytoplankton form the base of the ocean foodchain
PhytoplanktonDinoflagellateDiatoms

The most important groups of phytoplankton include thediatoms anddinoflagellates. Diatoms are especially important in oceans, where they are estimated to contribute up to 45% of the total ocean's primary production.[6] Diatoms are usuallymicroscopic, although some species can reach up to 2 millimetres (0.079 in) in length.

The second trophic level (primary consumers) is occupied byzooplankton which feed off thephytoplankton. Together with the phytoplankton, they form the base of the food pyramid that supports most of the world's great fishing grounds. Zooplankton are tiny animals found with the phytoplankton inoceanicsurface waters, and include tinycrustaceans, and fish larvae andfry (recently hatched fish). Most zooplankton arefilter feeders, and they use appendages to strain the phytoplankton in the water. Some larger zooplankton also feed on smaller zooplankton. Some zooplankton can jump about a bit to avoid predators, but they cannot really swim. Like phytoplankton, they float with the currents, tides and winds instead. Zooplanktons can reproduce rapidly, their populations can increase up to thirty percent a day under favourable conditions. Many live short and productive lives and reach maturity quickly.

Zooplankton form the second level in the ocean food chain
Segmented wormTiny shrimp-like crustaceansJuvenile planktonic squid

Particularly important groups of zooplankton are thecopepods andkrill. These are not shown in the images above, but are discussed in more detail later.Copepods are a group of smallcrustaceans found in ocean andfreshwaterhabitats. They are the biggest source of protein in the sea,[7] and are important prey for forage fish.Krill constitute the next biggest source of protein. Krill are particularly large predator zooplankton which feed on smaller zooplankton. This means they really belong to the third trophic level, secondary consumers, along with the forage fish.

Together,phytoplankton andzooplankton make up most of theplankton in the sea. Plankton is the term applied to any small driftingorganisms that float in the sea (Greekplanktos = wanderer or drifter). By definition, organisms classified as plankton are unable to swim against ocean currents; they cannot resist the ambient current and control their position. In ocean environments, the first two trophic levels are occupied mainly byplankton. Plankton are divided into producers and consumers. The producers are the phytoplankton (Greekphyton = plant) and the consumers, who eat the phytoplankton, are the zooplankton (Greekzoon = animal).

Diet

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External images
image iconForage fish and the food web
image iconFishing down marine food webs

Forage fish feed onplankton. When they are eaten by larger predators, they transfer this energy from the bottom of the food chain to the top and in this way are the central link betweentrophic levels.[8]

Forage fish are usuallyfilter feeders, meaning that they feed by straining suspended matter and food particles from water. They usually travel in large, slow moving, tightly packedschools with their mouths open. They are typicallyomnivorous. Their diet is usually based primarily on zooplankton, although, since they are omnivorous, they also take in some phytoplankton.

Young forage fish, such as herring, mostly feed onphytoplankton and as they mature they start to consume larger organisms. Older herrings feed onzooplankton, tiny animals that are found inoceanicsurface waters, andfish larvae andfry (recently hatched fish).Copepods and other tinycrustaceans are common zooplankton eaten by forage fish. Duringdaylight, many forage fish stay in the safety of deep water, feeding at the surface only at night when there is less chance of predation. They swim with their mouths open, filtering plankton from the water as it passes through their gills.

Oceanhalfbeaks areomnivores which feed onalgae, plankton, marine plants likeseagrass, invertebrates likepteropods andcrustaceans and smaller fishes.[9] Some tropical species feed on animals during the day and plants at night, while others alternate summer carnivory with winter herbivory.[10] They are in turn eaten bybillfish,mackerel, andsharks.[11]

Predators

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Forage fish are the food that sustains larger predators above them in the ocean food chain. The superabundance they present in their schools make them ideal food sources for top predator fish such astuna,striped bass,cod,salmon,barracuda andswordfish, as well assharks,whales,dolphins,porpoises,seals,sea lions, andseabirds.[5]

Ocean predators of forage fish
TunaSharkStriped bass
Leopard sealDolphinGannet

Schooling

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See also:Shoaling and schooling
Underwater video loop of a school of herrings migrating at high speed to their spawning grounds in theBaltic Sea

Forage fish compensate for their small size by formingschools. These sometimes immense gatherings fuel the ocean food web. Most forage fish arepelagic fish, which means they form their schools in open water, and not on the bottom (benthic fish) or near the bottom (benthopelagic fish). They are short-lived, and go mostly unnoticed by humans, apart from an occasional support role in a documentary about a great ocean predator. While we may not pay them much attention, the great marine predators are keenly focused on them, acutely aware of their numbers and whereabouts, and makemigrations that can span thousands of miles to connect with them. After all, forage fish are their food.[2]

Herring are among the most spectacular schooling fish. They aggregate together in huge numbers. Schools have been measured at over four cubic kilometres in size, containing about four billion fish.[12] These schools move along coastlines and traverse the open oceans. Herring schools in general have very precise arrangements which allow the school to maintain relatively constant cruising speeds. Herrings have excellent hearing, and their schools react very fast to a predator. The herrings keep a certain distance from a moving scuba diver or cruising predator like a killer whale, forming a vacuole which can look like a doughnut from a spotter plane.[13] The intricacies of schooling is far from fully understood, especially the swimming and feeding energetics. Many hypotheses to explain the function of schooling have been suggested, such as better orientation,synchronized hunting, predator confusion and reduced risk of being found. Schooling also has disadvantages, such as excretion buildup in the breathing media and oxygen and food depletion. The way the fish array in the school probably gives energy saving advantages, though this is controversial.[14]

On calm days, schools of herring can be detected at the surface a mile away by little waves they form, or from several meters at night when they triggerbioluminescence in surroundingplankton. Underwater recordings show herring constantly cruising at high speeds up to 108 cm per second, with much higher escape speeds.

They are fragile fish, and because of their adaptation to schooling behaviour they are rarely displayed inaquaria. Even with the best facilities aquaria can offer they become sluggish compared to their quivering energy in wild schools.

Copepod
Slow motion video loop of a juvenile herring feeding oncopepods

Hunting copepods

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Copepods are a group of smallcrustaceans found in ocean andfreshwaterhabitats. Many species areplanktonic (drifting in the ocean water), while others arebenthic (living on the sea floor). Copepods are typically one millimetre (0.04 in) to two millimetres (0.08 in) long, with a teardrop shaped body. Like othercrustaceans they have an armouredexoskeleton, but they are so small that this armour, and the entire body, is usually transparent.

Copepods are usually the dominantzooplankton. Some scientists say they form the largest animalbiomass on the planet. The other contender is theAntarctic krill. But copepods are smaller than krill, with faster growth rates, and they are more evenly distributed throughout the oceans. This means copepods almost certainly contribute more secondary production to the world's oceans than krill, and perhaps more than all other groups of marine organisms together. They are a major item on the forage fish menu.

Copepods are very alert and evasive. They have largeantennae. When they spread their antennae they can sense the pressure wave from an approaching fish and jump with great speed over a few centimeters.

Herrings are pelagic feeders. Their prey consists of a wide spectrum ofphytoplankton andzooplankton, amongst which copepods are the dominant prey. Youngherring usually capture small copepods by hunting them individually— they approach them from below. The (half speed) video loop at the left shows a juvenile herring feeding oncopepods. In the middle of the image a copepod escapes successfully to the left. Theopercula (hard bony flaps covering thegills) are spread wide open to compensate the pressure wave which would alert the copepod to trigger a jump.[1]

Herring ram feeding on a school ofcopepods
Juvenile herring hunt for the very alert and evasivecopepods in synchronization.(Click to animate).

If prey concentrations reach very high levels, the herrings adopt a method called "ram feeding". They swim with their mouth wide open and their opercula fully expanded. Every several feet, they close and clean theirgill rakers for a few milliseconds (filter feeding). In the photo on the right, herring ram feed on a school ofcopepods. The fish all open their mouths and opercula wide at the same time (the red gills are visible—click to enlarge). The fish swim in a grid where the distance between them is the same as the jump length of their prey, as indicated in the animation below.

In the animation, juvenile herring hunt thecopepods in synchronization: The copepods sense with theirantennae the pressure-wave of an approaching herring and react with a fast escape jump. The length of the jump is fairly constant. The fish align themselves in a grid with this characteristic jump length. A copepod can dart about 80 times before it tires out. After a jump, it takes it 60 milliseconds to spread its antennae again, and this time delay becomes its undoing, as the almost endless stream of herrings allows a herring to eventually snap the copepod. A single juvenile herring could never catch a large copepod.[1]

Migrations

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Coastalupwellings can provide plankton-rich feeding grounds for forage fish.
Migration of Icelandic capelin
See also:Fish migration

Forage fish often make greatmigrations between their spawning, feeding and nursery grounds. Schools of a particular stock usually travel in a triangle between these grounds. For example, one stock of herrings have their spawning ground in southernNorway, their feeding ground inIceland, and their nursery ground in northern Norway. Wide triangular journeys such as these may be important because forage fish, when feeding, cannot distinguish their own offspring.

Fertile feeding grounds for forage fish are provided by ocean upwellings.Oceanic gyres are large-scaleocean currents caused by theCoriolis effect. Wind-driven surface currents interact with these gyres and the underwater topography, such asseamounts and the edge ofcontinental shelves, to produce downwellings andupwellings.[15] These can transport nutrients which plankton thrive on. The result can be rich feeding grounds attractive to the plankton feeding forage fish. In turn, the forage fish themselves become a feeding ground for larger predator fish. Most upwellings are coastal, and many of them support some of the most productive fisheries in the world. Regions of notable upwelling include coastalPeru,Chile,Arabian Sea, westernSouth Africa, easternNew Zealand and theCalifornia coast.

Capelin are a forage fish of thesmelt family found in theAtlantic andArctic oceans. In summer, they graze on dense swarms ofplankton at the edge of the ice shelf. Larger capelin also eatkrill and othercrustaceans. The capelin move inshore in large schools to spawn and migrate in spring and summer to feed in plankton rich areas betweenIceland,Greenland, andJan Mayen. The migration is affected byocean currents. Around Iceland maturing capelin make large northward feeding migrations in spring and summer. The return migration takes place in September to November. The spawning migration starts north of Iceland in December or January.

The diagram on the right shows the mainspawning grounds andlarval drift routes. Capelin on the way to feeding grounds is coloured green, capelin on the way back is blue, and the breeding grounds are red. In a paper published in 2009, researchers from Iceland recount their application of an interacting particle model to the capelin stock around Iceland, successfully predicting the spawning migration route for 2008.[16]

Predator attacks

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See also:Bait ball andSardine run

Schooling forage fish are subject to constant attacks by predators. An example is the attacks that take place during the Africansardine run. The African sardine run is a spectacular migration by millions of silvery sardines along the southerncoastline of Africa. In terms of biomass, the sardine run could rival East Africa's greatwildebeest migration.[17]

External images
image iconDolphins herd sardines[18]
image iconGannets "divebomb" sardines[18]
Gannet

Sardines have a short life-cycle, living only two or three years. Adult sardines, about two years old, mass on theAgulhas Bank where they spawn during spring and summer, releasing tens of thousands of eggs into the water. The adult sardines then make their way in hundreds of shoals towards the sub-tropical waters of theIndian Ocean. A larger shoal might be 7 kilometers (4.3 miles) long, 1.5 kilometers (0.93 miles) wide and 30 meters (98 feet) deep. Huge numbers of sharks, dolphins, tuna, sailfish,Cape fur seals and even killer whales congregate and follow the shoals, creating afeeding frenzy along the coastline.[18]

When threatened, sardines instinctively group together and create massivebait balls. Bait balls can be up to 20 meters (66 feet) in diameter. They are short lived, seldom lasting longer than 20 minutes. As many as 18,000 dolphins, behaving like sheepdogs, round the sardines into these bait balls, or herd them to shallow water (corralling) where they are easier to catch. Once rounded up, the dolphins and other predators take turns plowing through the bait balls, gorging on the fish as they sweep through. Seabirds also attack them from above, flocks ofgannets,cormorants,terns andgulls. Some of these seabirds plummet from heights of 30 metres (98 feet), plunging through the water leaving vapour-like trails behind like fighter planes.[18]

The eggs, left behind at the Agulhas Banks, drift northwest with the current into waters off the west coast, where the larvae develop into juvenile fish. When they are old enough, they aggregate into dense shoals and migrate southwards, returning to the Agulhas banks in order to restart the cycle.[18]

Forage fisheries

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History

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Medieval herring fishing inScania (published 1555).

Herring has been known as astaple food source since 3000 B.C. InRoman times, anchovies were the base for the fermented fish sauce calledgarum. This staple of cuisine was produced in industrial quantities and transported over long distances.

Fishing for sardela or sardina (Sardina pilchardus) is an ongoing activity on theCroatianAdriatic coasts ofDalmatia andIstria. It traces its roots back thousands of years. The region was then largely aVenetian dominion, part of theRoman Empire. The area has always been sustained through fishing mainly sardines. Along the coast towns still promote the traditional practice of fishing bylateen sail boats for tourism and festivals.

Pilchard fishing and processing thrived inCornwall between 1750 and 1880, after which stocks went into an almost terminal decline. Recently (2007) stocks have been improving. The industry has featured in many works of art, includingStanhope Forbes and otherNewlyn School artists.

Contemporary

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This article is part of a series on
Commercial fish
Large predatory
Forage
Demersal
Mixed
Purse seine boats encircling a school ofmenhaden
Commercial herring catch

Traditionalcommercial fisheries were directed towards high value ocean predators such ascod,rockfish andtuna, rather than forage fish. As technologies developed, fisheries became so effective at locating and catching predator fish that many of the stocks collapsed. The industry compensated by turning to species lower in the food chain.[2]

In former times, forage fish were more difficult to fish profitably, and were a small part of the global marine fisheries. But modern industrial fishing technologies have enabled the removal of increasing quantities. Industrial-scale forage fish fisheries need large scale landings of fish to return profits. They are dominated by a small number of corporate fishing and processing companies.[5]

Forage fish populations are very vulnerable when faced with modern fishing equipment. They swim near the surface in compacted schools, so they are relatively easy to locate at the surface with sophisticated electronicfishfinders and from above withspotter planes. Once located, they are scooped out of the water using highly efficient nets, such aspurse seines, which remove most of the school.

Spawning patterns in forage fish are highly predictable. Some fisheries use knowledge of these patterns to harvest the forage species as they come together to spawn, removing the fish before they have actually spawned.[2] Fishing during spawning periods or at other times when forage fish amass in large numbers can also be a blow to predators. Many predators, such as whales, tuna and sharks, have evolved to migrate long distances to specific sites for feeding and breeding. Their survival hinges on their finding these forage schools at their feeding grounds. The great ocean predators find that, no matter how they are adapted for speed, size, endurance or stealth, they are on the losing side when faced with the machinery of contemporary industrial fishing.[2]

Altogether, forage fish account for 37 percent (31.5 million tonnes) of all fish taken from the world's oceans each year. However, because there are fewer species of forage fish compared to predator fish, forage species fisheries are the largest in the world. Seven of the top ten fisheries target forage fish.[5] The total world catch of herrings, sardines and anchovies alone in 2005 was 22.4 million tonnes, 24 percent of the total world catch.[19]

The Peruviananchoveta fishery is now the biggest in the world (10.7 million tonnes in 2004), while the Alaskanpollock fishery in theBering Sea is the largest single species fishery in the world (3 million tonnes). The Alaskan pollock is said to be the largest remaining single species source of palatable fish in the world.[20] However, the biomass of pollock has declined in recent years, perhaps spelling trouble for both theBering Sea ecosystem and the commercial fishery it supports. Acoustic surveys byNOAA indicate that the 2008 pollock population is almost 50 percent lower than last year's survey levels.[citation needed] Some scientists think this decline in Alaska pollock could repeat the collapse experienced byAtlantic cod, which could have negative consequences for the entire Bering Sea ecosystem. Salmon, halibut, endangered Steller sea lions, fur seals, and humpback whales eat pollock and depend on healthy populations to sustain themselves.[21]

Use as animal feed

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Eighty percent of the forage fish caught are fed to animals, in large part due to the high content of beneficial long chainomega-3 fatty acids in their flesh. Ninety percent is processed intofishmeal andfish oil. Of this, 46 percent was fed tofarmed fish, 24 percent to pigs, and 22 percent to poultry (2002).[4][22][23] Six times the weight of forage fish is fed to pigs and poultry alone than the entire seafood consumption of the U.S. market. One of the most promising alternatives to fish oil as a source of long chain omega-3 fatty acids and certain amino acids is algal oil frommicroalgae, the original source of these fatty acids in forage fish.[24]

According to Turchini and De Silva (2008), another 2.5 million tonnes of the annual forage fish catch is consumed by the globalcat food industry. In Australia, pet cats eat 13.7 kilograms of fish a year compared to the 11 kilograms eaten by the average Australian. The pet food industry is increasingly marketing premium and super-premium products, when different raw materials, such as the by-products of the fish filleting industry, could be used instead.[25]

Environmental issues

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In 2008 theSea Around Us Project completed a nine-year study of forage fish led by the fisheries scientists Jacqueline Alder andDaniel Pauly. They concluded that...[4]

  1. The composition of landings of forage fish fisheries have changed over the past 50 years with thetrophic level of fish used in fishmeal increasing over the past 20 years.
  2. Our understanding of the role of forage fish inmarine ecosystem and theimpact of fishing is still limited.
  3. Landing of forage fish peaked by the 1970s, and these high levels are highly unlikely in the future, even if fisheries are managed sustainably.
  4. The consumption of forage fish by seabirds and marine mammals is not likely to be onerous to fisheries, except in a few localized areas. By contrast, fisheries, by reducing the biomass of small pelagics, might pose a threat to these predators, particularly to those species for which stocks have been heavily depleted by human exploitation in the past.
  5. Some forage fish species are consumed by many people with consumption patterns changing over the last 20 years.
  6. Aquaculture continues to increase its consumption of fishmeal and fish oil.

In 2015sardine populations crashed along the west coast of the United States, causing the fishery to close early and remain closed through the 2015–2016 season.[26] A key reason for the population crash, wasoverfishing due to the demand of fish meals and fish oil used in feed for aquaculture and for human nutritional supplements.[27] In an effort to provide some relief from the pressure put on forage fish populations, the World Bank along with the University of Arizona, Monterey Bay Aquarium and the New England Aquarium has sponsored a competition called the F3 (Fish-Free Feed) Challenge, which will award $200,000 to the most successful fish feed manufacturer who develops aquaculture feeds not made from fish.[28]

In lakes and rivers

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Forage fish also inhabit freshwater habitats, such as lakes and rivers, where they serve as food for larger freshwater predators. Usually smaller than 15 centimetres (6 in) in length, these smallbait fish make up most of the fish found in lakes and rivers. Theminnow family alone, consisting ofminnows,chubs,shiners anddaces, consists of more than fifty species.[29] Other freshwater forage fish includesuckers,killifish,shad,bony fish as well as fish of thesunfish family, excludingblack basses andcrappie, and smaller species of thecarp family. There are alsoanadromous forage fish, such aseulachon.

Freshwater forage fish
Golden shinerKillifishSouthern redbelly dace
Chinese minnowSwarm of carpTwaite shad

In the context of human activity, within any fresh orsaltwater ecosystem, there will always be both desirable and undesirable fishes, and this varies from country to country, and often from region to region within a country.Sport fishermen divide freshwater predators of forage fish into those:

Rough or coarse fish usually refers to fish that are not commonly eaten, not sought after for sporting reasons, or have become invasive species reducing the populations of desirable fish. They compete for forage fish with the more popular sport fish. They are often regarded as a nuisance, and are not usually protected by game laws.[29] Forage fish generally are not considered rough or coarse fish because of their usefulness as bait.

The termrough fish is used by U.S. state agencies and anglers to describe undesirable predator fish. In North America, anglers fish forsalmon,trout,bass,pike,catfish,walleye andmuskellunge. The smallest fish are calledpanfish, because they can fit in a standard cooking pan. Some examples arecrappies,rock bass,perch,bluegill andsunfish.

The termcoarse fish originated in the United Kingdom in the early 19th century. Prior to that time, recreational fishing was the sport of thegentry, who angled fortrout andsalmon which they called "game fish". Fish other than game fish were disdained as "coarse fish".[30] These days, "game fish" refers toSalmonids (other thangrayling) — that is,salmon,trout andchar. Coarse fish are made up mostly of the larger species ofCyprinids (carp,roach,bream) as well aspike,catfish,gar andlamprey. Coarse fish are no longer disdained; indeed,fishing for coarse fish has become a popular pastime.

Freshwater predators of forage fish
Brook troutBlack crappieMacquarie perch
Rainbow troutPink salmonChannel catfish

Bait and feeder fish

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Forage fish are sometimes referred to asbait fish orfeeder fish.Bait fish is a term used particularly by recreational fishermen, although commercial fisherman also catch fish to baitlonglines andtraps. Forage fish is afisheries term, and is used in the context of fisheries. Bait fish, by contrast, are fish that are caught by humans to use as bait for other fish. The terms overlap in the sense that most bait fish are also forage fish, and vice versa.Feeder fish is a term used particularly in the context of fishaquariums. It refers essentially to the same concept as forage fish, small fish that are eaten by larger fish, but the term is adapted to the particular requirements of working with fish in aquariums.

Timeline

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  • 2006: The U.S.National Coalition for Marine Conservation asks U.S. fishery managers to put "Forage First!". Their campaign was launched with the publication of their report,Taking the Bait: Are America’s Fisheries Out-competing Predators for their Prey?,[31] available at cost to the U. S. fishing industry, encouraging fishery managers to protect predator–prey relationships as a first step toward anecosystem based approach to fishery management.[2]
  • 2009: The international Lenfest Forage Fish Task Force is established to develop workable management plans for tackling the depletion of forage fish.[32]
  • 2015: sardine populations crashed along the west coast of the United States.[26]

Recent reports

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See also

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Notes

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  1. ^abcKils, U (1992)The ecoSCOPE and dynIMAGE: Microscale tools for in situ studies of predator–prey interactions. Arch Hydrobiol Beih 36: 83–96
  2. ^abcdefgNational Coalition for Marine Conservation:Forage fishArchived 2008-12-17 at theWayback Machine
  3. ^U.S. Geological Survey:Forage FishArchived 2008-09-16 at theWayback Machine Alaska Science Center
  4. ^abcAlder, Jacqueline; Campbell, Brooke; Karpouzi, Vasiliki; Kaschner, Kristin; Pauly, Daniel (2008)."Forage Fish: From Ecosystems to Markets".Annual Review of Environment and Resources.33:153–166.doi:10.1146/annurev.environ.33.020807.143204.
  5. ^abcdMarine Fish Conservation Network:Forage fish: The Most Important Fish in the SeaArchived 2008-12-05 at theWayback Machine
  6. ^Mann, D. G. (1999). "The species concept in diatoms".Phycologia.38 (6):437–495.doi:10.2216/i0031-8884-38-6-437.1.
  7. ^Biology of CopepodsArchived 2009-01-01 at theWayback Machine atCarl von Ossietzky University of Oldenburg
  8. ^Forage fish: The most important fish in the sea
  9. ^Randall, J (1967)."Food habits of reef fishes of the West Indies"(PDF Converted to digital format byNOAA, 2004).Studies in Tropical Oceanography.5:665–847.
  10. ^Tibbetts, I; Carseldine, L (2005). "Trophic shifts in three subtropical Australian halfbeaks (Teleostei: Hemiramphidae)".Marine & Freshwater Research.56 (6):925–932.doi:10.1071/MF04305.
  11. ^Mahmoudi, B; McBride, R (2002)."A review of Florida's halfbeak bait fishery and halfbeak biology, and a preliminary stock assessment"(PDF). Florida Fish and Wildlife Conservation Commission. Archived fromthe original(PDF) on 2007-10-25.
  12. ^Radakov DV (1973)Schooling in the ecology of fish. Israel Program for Scientific Translation, translated by Mill H. Halsted Press, New York.ISBN 9780706513516
  13. ^Nøttestad, L and Axelsen, BE (1999)Herring schooling manoeuvres in response to killer whale attacks Canadian Journal of Zoology, 77: 1540–1546.
  14. ^Pitcher, TJ and Parrish, JK (1993) Behaviour of Teleost Fishes, Chp 12:Functions of shoaling behaviour in teleosts Springer.ISBN 9780412429309
  15. ^Wind Driven Surface Currents: Upwelling and Downwelling
  16. ^Barbaro1 A, Einarsson B, Birnir1 B, Sigurðsson S, Valdimarsson S, Pálsson ÓK, Sveinbjörnsson S and Sigurðsson P (2009)"Modelling and simulations of the migration of pelagic fish"Journal of Marine Science,66(5):826–838.
  17. ^Marine Scientists Scratch Heads Over Sardines
  18. ^abcdeSardine Run Shark Feeding Frenzy Phenomenon in AfricaArchived 2008-12-02 at theWayback Machine
  19. ^FAO (2005)Review of the state of world marine fishery resources. Fisheries technical paper T457,ISBN 92-5-105267-0
  20. ^Clover, Charles. 2004.The End of the Line: How Overfishing is Changing the World and What We Eat. Ebury Press, London.ISBN 0-09-189780-7
  21. ^Greenpeace:Rethinking sustainability: A new paradigm for fisheries managementArchived 2009-03-25 at theWayback Machine
  22. ^World's Fish Catches Being Wasted As Animal Feed Terra Daily. Retrieved 1 December 2008.
  23. ^New Study to Highlight Waste of Seafood The FishSite. Retrieved 1 December 2008
  24. ^Michael B. Rust, et al., The Future of Aquafeeds, NOAA/USDA Alternative Feeds Initiative, NOAA Technical Memorandum NMFS F/SPO-124, December 2011, seehttp://docs.lib.noaa.gov/noaa_documents/NMFS/TM_NMFS_FSPO/NMFS_FSPO_tm124.pdf
  25. ^Our pets’ gourmet tastes are putting pressure on dwindling fish stocks – Deakin University
  26. ^abPlunging sardine numbers spark quick management responseChinook Observer, 14 April 2015.
  27. ^Fish Oil Market Analysis By Application (Aquaculture (Salmon & Trout, Marine Fish, Crustaceans, Tilapias), Direct Human Consumption) And Segment Forecasts To 2022Grand View Research, February 2016.
  28. ^The Race to Find Fish Feeds That Don’t Bankrupt the OceanNational Geographic, 24 May 2016.
  29. ^abKleber, John E (1992)The Kentucky Encyclopedia University Press of Kentucky, Page 320.ISBN 9780813117720
  30. ^Lowerson, John (1993)Sport and the English middle classes, 1870–1914. Manchester University Press.ISBN 0719037778
  31. ^National Coalition for Marine Conservation:Forage First!Archived 2008-05-11 at theWayback Machine
  32. ^"Lenfest Forage Fish Task Force Launched |".SBU News. 2009-05-29. Retrieved2022-11-29.

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