Semotilus corporalisAmerican chub(Also: Chivin; Corporal; Dace; Fallfish)

Ge­o­graphic Range

Fall­fish (Se­motilus cor­po­ralis) are na­tive only in the North Amer­ica (Neartic re­gion). The north­ern range of fall­fish is as far north as the south­ern tip of the Hud­son bay in Canada. The south­ern bor­der of their range is the U.S bor­der be­tween Vir­ginia and North Car­olina. These fish range as far west as the Ap­palachian Moun­tains in the U.S and as far as Lake Su­pe­rior in Canada. The east­ern bor­der reaches the At­lantic ocean, but does not in­clude it.

In some parts of the range above (e.g., New York and Vir­ginia), fall­fish have been in­tro­duced into drainages. (May­den, 1991; ; Na­ture­Serve, 2013; Pin­der, 2017; Reed, 1971; Shel­don, 1968)

Habi­tat

Fall­fish are most com­mon in fresh­wa­ter low-gra­di­ent streams with for­est cover in ri­par­ian areas at el­e­va­tions be­tween 73 and 767 me­ters above sea level. These min­nows are lim­ited to tem­per­a­tures be­tween 6 and 27°C; how­ever, tem­per­a­tures below 15°C in­hibit spawn­ing. The young are often found in faster flow­ing cur­rents, while older min­nows can often be found in slower mov­ing pools along the stream. Across all ages, pools are the pre­ferred habi­tat. Fall­fish live and for­age in areas of the wa­ter­shed that are around 30-50 cm deep.

Fall­fish in north­ern parts of their ge­o­graphic ranges also live in lentic habits (lakes), while those in the south are re­stricted to lotic habi­tats. ("Habi­tat Suit­abil­ity In­for­ma­tion: Fall­fish", 1983; McKenna, et al., 2012; Na­ture­Serve, 2013; Pin­der, 2017; Shel­don, 1968)

  • Aquatic Biomes
  • rivers and streams
  • Range elevation
    73 to 767 m
    239.50 to 2516.40 ft
  • Range depth
    .3 to .5 m
    0.98 to 1.64 ft
  • Average depth
    .35 m
    1.15 ft

Phys­i­cal De­scrip­tion

Adult fall­fish are one of the largest min­nows in the U.S and Canada grow­ing to lengths be­tween 155-431 mil­lime­ters in length and girth up to 80 mil­lime­ters. Upon ma­tu­rity, fall­fish weigh be­tween 720 to 1800 grams. The fe­males grow to longer lengths then their male coun­ter­parts reach­ing an av­er­age length of 166 mm where as males grow to lengths of 155 mm.

Fall­fish heads are rounded and smooth due to a lack of scales. They have over­hang­ing mouthing form­ing a snout and a char­ac­ter­is­tic large eye. Adult fall­fish have thick, dark olive or golden-brown scales out­lined in black run­ning down their pos­te­rior spine. Their un­der­bel­lies are cov­ered in whitish-sil­ver scales. Their tails (cau­dal fin) bend down­ward and are forked and con­tain about 19 bony rays. The tips of their cau­dal fin is black. An­te­rior to the cau­dal fin, there are 8 rays that form the anal fin. Both cau­dal and anal fins are gen­er­ally the same color as the dor­sal scales. Their dor­sal fin is slightly in­fe­rior to the mid­point of their backs and con­tains 7 rays.

Pin­der (2017) re­ports that males in breed­ing con­di­tion have tu­ber­cles on their heads, con­cen­trated around their eyes and near their noses. Ju­ve­niles of this species have dark stripes along their lat­eral sides, reach­ing from head to tail. By ma­tu­rity, this stripe dis­ap­pears. (Bick­nell and Dress­lar, 1885; Na­ture­Serve, 2013; Pyron, 1996; Reed, 1971)

  • Sexual Dimorphism
  • female larger
  • sexes shaped differently
  • Range mass
    720 to 1800 g
    25.37 to 63.44 oz
  • Average mass
    820 g
    28.90 oz
  • Range length
    115 to 431 mm
    4.53 to 16.97 in
  • Average length
    160 mm
    6.30 in

De­vel­op­ment

Like most fish, fall­fish show in­de­ter­mi­nate growth over their lifes­pan. Males reach ma­tu­rity at around 3 years of age and the fe­male coun­ter­parts at 4 years of age. Upon hatch­ing, a yolk sack is left over on the fall­fish lar­vae for 5 to 7 days and will even­tu­ally be ab­sorbed once the lar­vae reach 9 mm in total body length. The fins of fall­fish lar­vae are ab­sent at hatch­ing and usu­ally don't de­velop until the lar­vae are at least 9 mm long. Once the lar­vae reach 9 to 11 mm total body length and fins are pre­sent, their mouths be­comes func­tional. At this time scales be­come pig­mented. The rays, or bony spines, of the fins de­velop around the time that the lar­vae reach 14 mm in total body length and pig­men­ta­tion of the scales in­ten­si­fies su­pe­rior to the de­vel­op­ing dor­sal fin. The fins fully de­velop when the lar­vae are at lengths over 18 mm. At this time, scale platelets form around the cau­dal pe­dun­cle and spread an­te­ri­orly until the lar­vae reach 33 mm. These scales are pig­mented dark olive to golden brown. (Buhan, 1972; Reed, 1971; Ross and Reed, 1978)

Re­pro­duc­tion

Fall­fish are polyg­y­nan­drous com­mu­nal breed­ers. In spawn­ing, males dis­play a nest build­ing be­hav­ior up­stream of ridges or pits in the stream bed. They spent 1-4 days col­lect­ing nearby peb­bles form­ing a mound where the fe­males' eggs will even­tu­ally lay. These peb­ble nests are around 30-50 cm wide and 10-20 cm high. They can be as large as 2 m in di­am­e­ter, mak­ing it the largest nest made by any fish.

After con­struc­tion, the nest-build­ing male re­leases pheromones at­tract­ing nearby fe­males in hope of re­pro­duc­tion. Other male fall­fish can also be at­tracted to an­other's nest, for­go­ing build­ing their own nest, in hopes of fer­til­iz­ing eggs re­leased by fe­males. This is re­ferred to as satel­lite male be­hav­ior. Younger males are known to dis­play satel­lite be­hav­ior more often than the older males.

Dur­ing re­pro­duc­tion, dom­i­nant nest build­ing males, and one to two satel­lite, or sub­dom­i­nate, males swim along­side one of the fe­males and bend their cau­dal pe­dun­cles along the uro­gen­i­tal open­ing su­pe­rior to the anal fin.​The dom­i­nant male's pe­dun­cle man­ages to reach the fe­male, stim­u­lat­ing her to raise her head and lower her cau­dal fin. This ac­tion causes the fe­male to re­lease her eggs in to the nest below. Satel­lite males then rush into the peb­ble nest to com­pete over fer­til­iz­ing the await­ing eggs. The fe­male en­gages in this spawn­ing ac­tiv­ity with the males that pre­sent a peb­ble for the nest. (Mau­rakis and Wool­cott, 1992; May­den, 1991; ; Na­ture­Serve, 2013; Reed, 1971; Ross and Reed, 1978; Ross, 1983)

Fall­fish are sea­sonal promis­cu­ous breed­ers, with one breed­ing sea­son per year. At this time, mul­ti­ple fe­males lay eggs in await­ing peb­ble nests, al­low­ing for males to fer­til­ize them. Nest-build­ing and satel­lite males at­tract and spawn with mul­ti­ple fe­males be­tween March and June. Fer­til­ized eggs take 139 to 144 hours (av­er­age = 140 h) to de­velop and hatch at tem­per­a­tures above 17 C. The num­ber of off­spring is var­ied de­pend­ing on their com­mu­nal breed­ing and satel­lite male re­pro­duc­tive suc­cess.

In­de­pen­dence is upon hatch­ing (no parental care) and birth weights have no been re­ported. Males reach sex­ual ma­tu­rity after 2 to 3 years, while their fe­male coun­ter­parts reach sex­ual ma­tu­rity after 3 to 4 years. (Mau­rakis and Wool­cott, 1992; May­den, 1991; ; Reed, 1971; Ross and Reed, 1978; Ross, 1983)

  • Breeding interval
    One breeding period per year
  • Breeding season
    between March and June with water temperature above 15°C
  • Range time to hatching
    139 to 144 hours
  • Average time to hatching
    140 hours
  • Average time to independence
    0 minutes
  • Range age at sexual or reproductive maturity (female)
    3 to 4 years
  • Range age at sexual or reproductive maturity (male)
    2 to 3 years

Nei­ther the male or fe­male fall­fish en­gage in any form of parental in­vest­ment be­yond the act of spawn­ing. De­spite this, nest-build­ing males de­vote time to cre­ate rocky peb­ble nests in order to at­tract fe­males for spawn­ing, but leave the nest after the eggs are fer­til­ized. The fe­males swim away from the nest after they have laid their eggs. (May­den, 1991; ; Ross and Reed, 1978; Ross, 1983)

  • Parental Investment
  • no parental involvement

Lifes­pan/Longevity

Fall­fish are known to live for 3-8 years with a max­i­mum lifes­pan reach­ing 10 years. No in­for­ma­tion has been found con­cern­ing whether fall­fish have ever been kept in cap­tiv­ity. (Reed, 1971; Vic­tor and Broth­ers, 1982)

  • Range lifespan
    Status: wild
    10 (high) years
  • Typical lifespan
    Status: wild
    3 to 8 years
  • Average lifespan
    Status: wild
    7 years

Be­hav­ior

Fall­fish are a din­ural species of min­now. This means that they for­age, re­pro­duce and per­form their other ac­tiv­i­ties dur­ing the day time hours. These min­nows are mi­gra­tory; they mi­gra­tion fol­lows of va­ri­ety of fac­tors such as food avail­abil­ity and water tem­per­a­ture. Fall­fish thrive higher water tem­per­a­tures around 20°C. The younger min­nows are often found in faster mov­ing cur­rents where food is at greater avail­abil­ity, but this be­hav­ior opens them up to pre­da­tion and human ac­tiv­i­ties such as fish­ing.

They are pri­mar­ily a soli­tary species being one of the top preda­tors in their habi­tat. They usu­ally in­terect with oth­ers of their species dur­ing spawn­ing be­hav­iors. Dom­i­nance in this species takes part in satel­lite nest­ing be­hav­iors for re­pro­duc­tion. (Allin, 1951; McKenna, et al., 2012; Shel­don, 1968)

Home Range

Fall­fish are very mo­bile. They have no true home range be­sides ac­cess to their en­tire stream. Their move­ments can in­flu­enced by a va­ri­ety of fac­tors in­clud­ing water level, food avail­abil­ity, water tem­per­a­ture, re­pro­duc­tive mates. (Allin, 1951; McKenna, et al., 2012; Shel­don, 1968)

Com­mu­ni­ca­tion and Per­cep­tion

Com­mu­ni­ca­tion be­tween fishes oc­curs using chem­i­cal mes­sen­gers called pheromones which are re­leased from their bod­ies. These pheromones travel through a medium, water in this case, and are re­ceived by spe­cial­ized cells on other aquatic life. Their pheromones can be harm­ful, in­hibitory, threat­en­ing or at­trac­tive. These chem­i­cal pheromones have been found to cor­re­late with sev­eral as­pects of fish be­hav­ior such as shoal­ing, hom­ing mi­grat­ing fish, alarm mech­a­nisms, crowd­ing con­trols and spawn­ing. Fish use pheromones to con­di­tion the water qual­ity to at­tract mates, prey or to repel oth­ers such as with an over­crowd­ing fac­tor. In spawn­ing be­hav­iors, males ex­crete an pheromone to at­tract fe­male fish. The pheromone at­tracts the fe­male to a wait­ing nest where the male would brush across the fe­male re­leas­ing fur­ther pheromone to sig­nal for the de­sire to spawn. (Buy­nak and Mohr Jr., 1979; Jolly, 1980; Solomon, 1977)

Food Habits

Fall­fish are om­niv­o­rous and are truly op­por­tunis­tic feed­ers. Their known diets con­sist of plank­ton, aquatic and ter­res­trial in­sects, in­sect lar­vae, small crus­taceans, fish, fish lar­vae, mol­lusks, leeches and algae. The con­sump­tion of algae, though sur­pris­ing, is a sta­ple food for most cyprinid species. Fall­fish pri­mar­ily hunt and for­age noc­tur­nally be­tween tca 2100 - 0500 h, with the most ac­tiv­ity around mid­night. The wild brown trout (Salmo trutta) and brook trout (Salveli­nus fonti­nalis) pro­vide di­rect com­pe­ti­tion in the for­ag­ing habits of fall­fish. ("Habi­tat Suit­abil­ity In­for­ma­tion: Fall­fish", 1983; John­son, 2015; May­den, 1991; ; McKenna, et al., 2012; Reed, 1971)

  • Animal Foods
  • fish
  • eggs
  • insects
  • terrestrial non-insect arthropods
  • mollusks
  • aquatic or marine worms
  • aquatic crustaceans

Pre­da­tion

Fall­fish are known to fall prey to larger fall­fish as well as north­ern pike (Esox lu­cius) and fish-eat­ing birds such as os­preys (Pan­dion hali­ae­tus) and the Amer­i­can her­ring gull (Larus smith­so­ni­anus). (McKenna, et al., 2012; Men­dall, 1939)

  • Known Predators

Ecosys­tem Roles

Fall­fish are com­monly one of the top preda­tors in their en­vi­ron­ments. In Vir­ginia, Pin­der (2017) notes that fall­fish were typ­i­cally the apex preda­tor in their en­vi­rons until some species of bass were in­tro­duced.

They are often found to be in­fect with four known gen­era of par­a­sites: Neoechi­norhynchi, All­crea­d­ium, Dacty­lo­cyrus and Er­gasilus. Mem­bers of the genus Neoechi­norhynchi are par­a­sitic worms from the phy­lum Acan­tho­cephala that in­vade the bod­ies of fall­fish. Par­a­sitic crus­taceans, Er­gasilus, are also known as gill lice; they in­fect the gills of fall­fish. Trema­todes in the genus Dacty­l­o­gyrus also in­fect the gills of fresh­wa­ter fish. Al­locre­a­d­ium is a genus of trema­tode par­a­sites that in­fect the in­testines of ma­rine fish. (Hoff­man, 1999; McKenna, et al., 2012; Pin­der, 2017; Rand and Burt, 1985; Vic­tor and Broth­ers, 1982)

Com­men­sal/Par­a­sitic Species
  • Worm (Neoechi­norhynchi)
  • Louse (Erasilus)
  • Trema­tode (Al­locre­a­d­ium)
  • Trema­tode (Dactyl­gryus)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Fall­fish pro­mote eco­tourism in the Great Lakes and other wa­ter­sheds within their habi­tat. Fall­fish are used as bait to catch larger fish. This pro­motes areas where fall­fish fre­quent, invit­ing peo­ple to visit. In Vir­ginia, they are pro­moted as a low-cost and typ­i­cally local op­tion for fish­ing. The taste of fall­fish is much de­bated. (Bon­coeur, et al., 2002; Pin­der, 2017; Scheyvens, 1999)

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

The pres­ence of fall­fish have no known neg­a­tive im­pact on hu­mans. (Bon­coeur, et al., 2002)

Con­ser­va­tion Sta­tus

Fall­fish are listed as a species of "Least Con­cern" on the IUCN redlist. Fall­fish have no spe­cial sta­tus on the U.S En­dan­gered Species list, the CITES ap­pen­dices and the state of Michi­gan list. There are no known on­go­ing con­ser­va­tion ef­forts con­cern­ing fall­fish. They are cur­rently no re­stric­tions in the use of fall­fish as bait. (Na­ture­Serve, 2013)

Con­trib­u­tors

jacob McCoy (au­thor), Rad­ford Uni­ver­sity, Alex At­wood (ed­i­tor), Rad­ford Uni­ver­sity, Lind­sey Lee (ed­i­tor), Rad­ford Uni­ver­sity, Karen Pow­ers (ed­i­tor), Rad­ford Uni­ver­sity, Joshua Turner (ed­i­tor), Rad­ford Uni­ver­sity, Tanya Dewey (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

freshwater

mainly lives in water that is not salty.

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

insectivore

An animal that eats mainly insects or spiders.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

molluscivore

eats mollusks, members of Phylum Mollusca

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

nomadic

generally wanders from place to place, usually within a well-defined range.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

phytoplankton

photosynthetic or plant constituent of plankton; mainly unicellular algae. (Compare to zooplankton.)

piscivore

an animal that mainly eats fish

planktivore

an animal that mainly eats plankton

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

Ref­er­ences

U.S De­part­ment of the In­te­rior. Habi­tat Suit­abil­ity In­for­ma­tion: Fall­fish. FWS/OBS-82/10.48. Fort Collins, Col­orado: Fish and Wildlife Ser­vice. 1983.

Allin, A. 1951. The fall­fish, Se­motilus cor­po­ralis, from the Lake Su­pe­rior drainage of west­ern On­tario. Copeia, 1951/4: 300.

Bick­nell, E., F. Dress­lar. 1885. A re­view of the species of the genus Se­motilus. Pro­ceed­ings of the Acad­emy of Nat­ural Sci­ences of Philadel­phia, 37: 14-18.

Bon­coeur, J., F. Alban, O. Guyador, O. The­baud. 2002. Fish, fish­ers, seals and tourists: Eco­nomic con­se­quences of cre­at­ing a ma­rine re­serve in a multi-species, multi-ac­tiv­ity con­text. Nat­ural Re­source Mar­ket­ing, 15/4: 387-411.

Buhan, P. 1972. The com­par­a­tive os­te­ol­ogy of the cau­dal skele­ton of some North Amer­i­can min­nows (Cyprinidae). The Amer­i­can Mid­land Nat­u­ral­ist, 88/2: 484-490.

Buy­nak, G., H. Mohr Jr.. 1979. Lar­val de­vel­op­ment of creek chub and fall­fish from two Susque­hanna River trib­u­taries. North Amer­i­can Jour­nal of Aqua­cul­ture, 41/3: 124-129.

Gill, T. 1907. Stone gath­er­ing fishes. The Amer­i­can Nat­u­ral­ist, 41/487: 368-369.

Hoff­man, G. 1999. Par­a­sites of North Amer­i­can Fresh­wa­ter Fishes. Ithaca, New York: Cor­nell Uni­ver­sity Press.

John­son, J., C. Nack, M. Chalup­nicki. 2009. Pre­da­tion by fall­fish, Se­motilus cor­po­ralis, on Pa­cific salmon eggs in the Salmon River, New York. Jour­nal of Great Lakes Re­search, 35/4: 630-633.

John­son, J. 2015. Sum­mer deil diet and feed­ing pe­ri­od­ic­ity of four species of Cryprinids in the Salmon River, New York. Amer­i­can Mid­land Nat­u­ral­ist, 173/2: 326-334.

Jolly, D. 1980. Pheromones in fish com­mu­ni­ca­tion. Ap­plied An­i­mal Be­hav­ior Sci­ence, 6/1: 90.

King, L. 2006. Creek chub and fall­fish. On­tario Out of Doors, 38/7: 64-65.

Mau­rakis, E., W. Wool­cott. 1992. Spawn­ing in Se­motilus cor­po­ralis. Vir­ginia Jour­nal of Sci­ence, 43/4: 377-380.

May­den, R. 1991. Cyprinids of the New World. Pp. 240-263 in I Win­field, J Nel­son, eds. Cyprinid Fishes: Sys­tem­at­ics, Bi­ol­ogy, and Ex­ploita­tion. Suf­folk, U.K.: Springer-Sci­ence + Busi­ness Media BV.

McKenna, J., J. Ru­girello, J. John­son. 2012. A land­scape-based dis­tri­b­u­tion model for fall­fish (Se­motilus cor­po­ralis) in the Great Lakes drainage of New York. Jour­nal of Great Lakes Re­search, 38/3: 413-417.

Men­dall, H. 1939. Food habits of the her­ring gull in re­la­tion to fresh-wa­ter game fishes in Maine. The Wil­son Bul­letin, 51/4: 223-226.

Muz­zall, P., W. Bul­lock. 1978. Sea­sonal oc­cur­rence and host-par­a­site re­la­tion­ships of Neoechi­norhynchus sag­i­na­tus Van Cleave and Bang­ham 1949 in the fall­fish, Se­motilus cor­po­ralis (Mitchill). The Jour­nal of Par­a­sitol­ogy, 64/5: 860-865.

Na­ture­Serve, 2013. "Se­motilus cor­po­ralis" (On-line). The IUCN Red List of Threat­ened Species 2013: e.T202371A18231202. Ac­cessed Jan­u­ary 30, 2018 at http://​dx.​doi.​org/​10.​2305/​IUCN.​UK.​2013-1.​RLTS.​T202371A18231202.​en.

Pin­der, M. 2017. "Fall­fish: Lit­tle tar­pon of the com­mon­wealth" (On-line). Ac­cessed April 15, 2018 at https://​blog.​wildlife.​virginia.​gov/​2016/​09/​fallfish-little-tarpon-of-the-commonwealth/​.

Pyron, M. 1996. Sex­ual size di­mor­phism and phy­logeny in North Amer­i­can min­nows. Bi­o­log­i­cal Jour­nal of the Lin­nean So­ci­ety, 57/4: 327-341.

Rand, T., M. Burt. 1985. Sea­sonal oc­cur­rence, re­cruit­ment and mat­u­ra­tion of Al­locre­a­d­ium lo­ba­tum Wallin, 1909 (Di­ge­nea: Al­locre­adi­idae) in the fall­fish, Se­motilus cor­po­ralis Mitchell, in a New Brunswick, Canada, lake sys­tem. Cana­dian Jour­nal of Zo­ol­ogy, 63/3: 612-616.

Reed, R. 1971. Bi­ol­ogy of the fall­fish, Se­motilus cor­po­ralis (Pisces, Cyprinidae). Trans­ac­tions of the Amer­i­can Fish­eries So­ci­ety, 100/4: 717-725.

Ross, M. 1983. The fre­quency of nest con­struc­tion and satel­lite male be­hav­ior in the fall­fish min­now. En­vi­ron­men­tal Bi­ol­ogy of Fishes, 9/1: 65-70.

Ross, M., R. Reed. 1978. The re­pro­duc­tive be­hav­ior of fall­fish Se­motilus cor­po­ralis. Copeia, 1978/2: 215-221.

Scheyvens, R. 1999. Eco­tourism and the em­pow­er­ment of local com­mu­ni­ties. Tourism Man­age­ment, 22/2: 245-249.

Shel­don, A. 1968. Species di­ver­sity and lon­gi­tu­di­nal suc­ces­sion in stream fishes. Ecol­ogy, 49/2: 193-198.

Solomon, D. 1977. A reveiw of chem­i­cal com­mu­ni­ca­tion in fresh­wa­ter fish. Jour­nal of Fish Bi­ol­ogy, 11/4: 363-376.

Vic­tor, B., E. Broth­ers. 1982. Age and growth of the fall­fish Se­motilus cor­po­ralis with daily otolith in­cre­ments as a method of an­nu­lus ver­i­fi­ca­tion. Cana­dian Jour­nal of Zo­ol­ogy, 60/1982: 2543-2550.