Rainbow smelt | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Osmeriformes |
Family: | Osmeridae |
Genus: | Osmerus |
Species: | O. mordax |
Binomial name | |
Osmerus mordax (Mitchill, 1814) | |
Subspecies | |
Osmerus mordax mordax(Mitchill, 1814) Contents |
The rainbow smelt (Osmerus mordax) is a North American species of fish of the family Osmeridae. Walleye, trout, and other larger fish prey on these smelt. The rainbow smelt prefer juvenile ciscoes, zooplankton such as calanoid copepods ( Leptodiaptomus ashlandi , L. minutus , L. sicilis ), and other small organisms, but are aggressive and will eat almost any fish they find. They are anadromous spring spawners and prefer clean streams with light flow and light siltation. The rainbow smelt face several barriers. They are weak swimmers and struggle to navigate fish ladders preventing them from making it past dams to the headwater streams where they spawn. [2] The rise in erosion and dams helped to decimate the smelt population in the 1980s. There are currently plans to try to reduce damming and to help control erosion.
The body of the rainbow smelt is slender and cylindrical. It has a silvery, pale green back and is iridescent purple, blue, and pink on the sides, with a light underside. When full grown, the rainbow smelt is between 7 and 9 inches (18 and 23 cm) long and weighs about 3 ounces (85 g). Individuals over 12 inches (30 cm) long are known. [3]
The rainbow smelt is widespread across North American watersheds. [4] The North American native range of the rainbow smelt extends through the Atlantic drainages between New Jersey and Labrador to Arctic drainages, and the Pacific drainages as far south as Vancouver Island. The rainbow smelt has been introduced into water bodies in the U.S. states of Colorado, Connecticut, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New York, North Carolina, North Dakota, Ohio, Pennsylvania, South Dakota, Tennessee, Vermont, Virginia, and Wisconsin. [5]
Rainbow smelt invaded the Great Lakes watershed through the intentional introduction of eggs from historically known landlocked populations in Maine to Crystal Lake, Michigan in 1912. [5] This lake drains into Lake Michigan, from which fish escaped into Lake Michigan and spread quickly throughout the Great Lakes and their tributaries. Early records documenting the smelt's range expansion in the Great Lakes include Lake Michigan, Lake Erie, Lake Huron, Lake Ontario, and Lake Superior. [5] Rainbow smelt were first reported from Lake Ontario in 1929, and probably reached it by dispersal along natural waterways from the Finger Lakes, New York, where they were intentionally introduced in 1917. The ability of rainbow smelt to disperse is determined by the connectivity of lakes, the ability of smelt to move through connecting streams, and the suitability of connected lakes as habitat. [6] Rainbow smelt are weak swimmers so they cannot make it over fish ladders. This has helped to prevent an even wider spread of their range. [2]
Rainbow smelt occur in rivers, coastal areas and ponds. In their anadromous territories, they spend the summers along the coast, normally in waters no more than 20 feet (6.1 m) deep and no more than 1 mile (1.6 km) from shore. They overwinter under the ice in estuaries, producing an antifreeze protein and glycerol. [7] In the spring, they spawn at night in small streams, often ones that go dry in the summer.
In 1883 Stedman and Argyle found that the rainbow smelt consumed bloaters (Coregonus hoyi) and alewives (Alosa pseudoharengus). However, they also stated that this predator had not affected the population of bloaters but that impact could be a possibility. [5] A 2003 study by Horppila et al. shows that smelt densities can exceed 40,000 individuals per hectare and may create a large predation pressure on the lake. [6] Horppila et al. also states that a single smelt can consume between 0.12 and 0.14 grams food wet weight per day. [6] Another study showed that in Lake Ontario the primary food sources for rainbow smelt were slimy sculpins (Cottus cognatus) and opossum shrimp (Mysis relicta), but nothing was said on whether this predation had significant impact on the populations. [5] In 1973 Havey reported that there was increased growth in landlocked Atlantic salmon populations after the introduction of the smelt. It was also shown by Brandt and Madon in 1986 that adult lake trout (Salvalinus namaycush) could be a keystone predator species for the smelt. [5] Hrabik et al. (1998) found evidence of competition for food between introduced rainbow smelt and native yellow perch (Perca flavescens) in Wisconsin lake habitats, and smelt may be partially responsible for the decline of Great Lakes whitefish ( Coregonus spp.). [5] The U.S. EPA stated in 2008 that they believe the smelt contributed to the extinction of the blue pike (Stizostedion vitreum glaucum) by outcompeting for food. [5] Acidity may alter smelt distributions because they were not found in small lakes with pH less than 6.0 in several surveys. Because of snowmelt, rainbow smelt eggs might be exposed to lethal pH decreases in poorly buffered lakes. [6]
Rainbow smelt are anadromous, ascending from saltwater to freshwater to spawn. Smelt are also capable of completing their life history exclusively in freshwater. Landlocked adult rainbow smelt spawn shortly after ice-off at night in the lower reaches of streams. [6] Shaw found in his research that no shoreline spawning had ever occurred. [8] McKenzie states that the number of eggs extruded by a female is positively related to its size and Nellbring stated in his 1989 research that the eggs are adhesive and attach to substrates such as gravel, sand, mud, or submerged vegetation. [6] Eggs are left unattended and hatch in 1–4 weeks, depending on water temperature. The time to sexual maturity is dependent on food supply and water temperature and abundant food and warmer temperatures encourage faster growth. [6] Crossman and Scott state that in optimal conditions and large lakes, rainbow smelt may reach 35.6 centimetres (14.0 in) and can live for over seven years. [6]
Rainbow smelt are fished both commercially and for sport. Commercial harvests are down from historic levels; for example around 1880 an annual harvest from the Charles River alone was around 9 million fish, while today few smelt are found in the Charles River. They are commonly processed into animal feed, but are also eaten by humans. They are a popular winter game fish and the spring smelt run is a tradition in many parts of their distribution. Fishing for rainbow smelt using a gill net has historically been a popular activity along the City of Chicago's lakefront. [9]
The populations of the rainbow smelt in areas where it has been introduced, such as the Great Lakes, have been increasing in many regions, even with efforts to control its spread. [10] Several things are being done to manage this species. Massive fish removal by over-fishing reduced the rainbow smelt populations in some lakes by the 1980s. [6] Some people are taking a chemical approach to this growing problem, using Rotenone. While this is effective, it also harms other organisms and is unpopular with the public. Cox and Kitchell state that declines in smelt numbers, following natural recovery or stocking of grown predator fish, have been reported from lakes ranging in size from Lake Superior and Hessen. Additionally, similar results were found in a small pond near Lillehammer, Norway in 1983.[ citation needed ] This research shows that the reintroduction of large piscivores such as walleye can help lead to the reduction of chemicals and poison needing to be used.[ citation needed ]
The rainbow smelt is a U.S. National Marine Fisheries Service Species of Concern, one of those species about which the U.S. Government's National Oceanic and Atmospheric Administration has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the U.S. Endangered Species Act (ESA). [11]
Smelts are a family of small fish, the Osmeridae, found in the North Atlantic and North Pacific oceans, as well as rivers, streams and lakes in Europe, North America and Northeast Asia. They are also known as freshwater smelts or typical smelts to distinguish them from the related Argentinidae, Bathylagidae, and Retropinnidae.
The brown trout is a species of salmonid ray-finned fish and the most widely distributed species of the genus Salmo, endemic to most of Europe, West Asia and parts of North Africa, and has been widely introduced globally as a game fish, even becoming one of the world's worst invasive species outside of its native range.
The alewife is an anadromous species of herring found in North America. It is one of the "typical" North American shads, attributed to the subgenus Pomolobus of the genus Alosa. As an adult it is a marine species found in the northern West Atlantic Ocean, moving into estuaries before swimming upstream to breed in freshwater habitats, but some populations live entirely in fresh water. It is best known for its invasion of the Great Lakes by using the Welland Canal to bypass Niagara Falls. Here, its population surged, peaking between the 1950s and 1980s to the detriment of many native species of fish. In an effort to control it biologically, Pacific salmon were introduced, only partially successfully. As a marine fish, the alewife is a US National Marine Fisheries Service "Species of Concern".
The rainbow trout is a species of trout native to cold-water tributaries of the Pacific Ocean in North America and Asia. The steelhead is an anadromous (sea-run) form of the coastal rainbow trout(O. m. irideus) or Columbia River redband trout (O. m. gairdneri) that usually returns to freshwater to spawn after living two to three years in the ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are also called steelhead.
Steelhead, or occasionally steelhead trout, is the anadromous form of the coastal rainbow trout (Oncorhynchus mykiss irideus) or Columbia River redband trout. Steelhead are native to cold-water tributaries of the Pacific basin in Northeast Asia and North America. Like other sea-run (anadromous) trout and salmon, steelhead spawn in freshwater, smolts migrate to the ocean to forage for several years and adults return to their natal streams to spawn. Steelhead are iteroparous, although survival is only approximately 10–20%.
The ciscoes are salmonid fish that differ from other members of the genus Coregonus in having upper and lower jaws of approximately equal length and high gill raker counts. These species have been the focus of much study recently, as researchers have sought to determine the relationships among species that appear to have evolved very recently. Cisco is also specifically used for the North American species Coregonus artedi, also known as lake herring.
The Atlantic salmon is a species of ray-finned fish in the family Salmonidae. It is the third largest of the Salmonidae, behind Siberian taimen and Pacific Chinook salmon, growing up to a meter in length. Atlantic salmon are found in the northern Atlantic Ocean and in rivers that flow into it. Most populations are anadromous, hatching in streams and rivers but moving out to sea as they grow where they mature, after which the adults seasonally move upstream again to spawn.
The Arctic char or Arctic charr is a cold-water fish in the family Salmonidae, native to alpine lakes, as well as Arctic and subarctic coastal waters in the Holarctic.
The blackfin cisco was a North American salmonid fish in the freshwater whitefish sub-family Coregoninae. This silvery, deep-bodied fish with black fins, large eyes, a blunt snout and a terminal mouth, was one of the largest forms of ciscoes. The blackfin cisco used to inhabit the Great Lakes of North America until recently, but has been reported to have gone extinct. The blackfin cisco is a member of the C. artedi complex, whose taxonomy has not yet been resolved, and it may not represent a valid species.
The Arctic cisco, also known as omul, is an anadromous species of freshwater whitefish that inhabits the Arctic parts of Siberia, Alaska and Canada. It has a close freshwater relative in several lakes of Ireland, known as the pollan, alternatively regarded as conspecific with it, or as a distinct species.
The round whitefish is a freshwater species of fish that is found in North American drainages from Alaska to New England, including the Great Lakes except for Lake Erie, and in Arctic tributaries of northeast Asia, as well as northern Kamchatka Peninsula and the northern coasts of the Sea of Okhotsk. It has an olive-brown back with light silvery sides and underside and its length is generally between 9 and 19 inches. They are bottom feeders, feeding mostly on invertebrates, such as crustaceans, insect larvae, and fish eggs. Some other fish species, like white sucker in turn eat their eggs. Lake trout, northern pike and burbot are natural predators. Other common names of the round whitefish are Menominee, pilot fish, frost fish, round-fish, and Menominee whitefish. The common name "round whitefish" is also sometimes used to describe Coregonus huntsmani, a salmonid more commonly known as the Atlantic whitefish.
Coregonus hoyi, also known as the bloater, is a species or form of freshwater whitefish in the family Salmonidae. It is a silvery-coloured herring-like fish, 25.5 centimetres (10.0 in) long. It is found in most of the Great Lakes and in Lake Nipigon, and inhabits underwater slopes. This fish is not to be confused with the extinct deepwater cisco, a large fish that shared a common name with the bloater.
The Atlantic whitefish is a coregonine fish inhabiting some freshwater lakes within Nova Scotia, Canada. It is known to survive only in the Petite Rivière watershed as landlocked populations. Earlier it was also found in the Tusket and Annis rivers of Nova Scotia. Those populations were anadromous, migrating to the estuary to feed while breeding in freshwater.
The shortjaw cisco is a North-American freshwater whitefish in the salmon family. Adult fish range to about 30 cm (12 in) in length and are silver, tinged with green above and paler below. One of the members of the broader Coregonus artedi complex of ciscoes, it is distributed widely in the deeper lakes of Canada, but populations in the Great Lakes have been declining and it is no longer present in Lakes Michigan, Huron, and Erie. It feeds mainly on crustaceans and insect larvae and spawns in the autumn on the lake bed. It is part of the important cisco (chub) fishery in the Great Lakes. The International Union for Conservation of Nature has rated its conservation status as "vulnerable". Shortjaw cisco have however evolved from the cisco Coregonus artedi independently in different lakes and different parts of the range, and conservation assessments therefore should be made on a lake-wise rather than range-wide basis.
The kiyi is a species of freshwater whitefish, a deepwater cisco, endemic to the Great Lakes of North America. It previously inhabited Lake Superior, Lake Michigan, Lake Huron and Lake Ontario, but is now believed to persist only in Lake Superior where it is common. The various deepwater ciscos are also called chubs. The kiyi is part of the large group of related northern ciscos known as the Coregonus artedi complex.
Coregonus artedi, commonly known as the cisco, is a North American species of freshwater whitefish in the family Salmonidae. The number of species and definition of species limits in North American ciscoes is a matter of debate. Accordingly, Coregonus artedi may refer either in a narrow sense to one of the several types of cisco found e.g. in the Great Lakes, or in a broad sense to the complex of all ciscoes in continental North American lakes, Coregonus artedi sensu lato.
The Sebasticook River is a 76-mile-long (122 km) river in the central part of Maine, in the United States. From its source in Dexter, the upper "Main Stream" section flows generally west and south 30 miles (48 km) to Great Moose Lake. From the outlet of the lake in Hartland, the Sebasticook flows 41 miles (66 km) south to the Kennebec River in Winslow.
The pygmy smelt is a North-American freshwater fish in the family Osmeridae. It is found in a number of deep, thermally stratified lakes in eastern Canada and New England.
The lake whitefish is a species of freshwater whitefish from North America. Lake whitefish are found throughout much of Canada and parts of the northern United States, including all of the Great Lakes. The lake whitefish is sometimes referred to as a "humpback" fish due to the small size of the head in relation to the length of the body. It is a valuable commercial fish, and also occasionally taken by sport fishermen. Smoked, refrigerated, vacuum-packed lake whitefish fillets are available in North American grocery stores. Other vernacular names used for this fish include Otsego bass, Sault whitefish, gizzard fish, common whitefish, eastern whitefish, Great Lakes whitefish, humpback whitefish, inland whitefish and whitefish.
The kokanee salmon, also known as the kokanee trout, little redfish, silver trout, kikanning, Kennerly's salmon, Kennerly's trout, or Walla, is the non-anadromous form of the sockeye salmon. There is some debate as to whether the kokanee and its sea-going relative are separate species; geographic isolation, failure to interbreed, and genetic distinction point toward a recent divergence in the history of the two groups. The divergence most likely occurred around 15,000 years ago when a large ice melt created a series of freshwater lakes and rivers across the northern part of North America. While some members of the salmon and trout family (salmonids) went out to sea (anadromous), others stayed behind in fresh water (non-anadromous). The separation of the sockeye and the kokanee created a unique example of sympatric speciation that is relatively new in evolutionary terms. While they occupy the same areas and habitats during the breeding season, when ocean-going sockeye salmon return to freshwater to spawn, the two populations do not mate with each other in some regions, suggesting speciation.