Male - Male sexual dimorphism



Species Primary Data Secondary Data References
Alosa alosa None Absent Spillmann, 1961
Alosa fallax Males mature a year earlier Absent Aprahamian, 2001
Alosa sapidissima In all populations and years, males matured at a significantly younger age than females Absent Carscaden and Legget, 1975
Barbatula barbatula The second ray of pectoral fin is enlarged and longer, the second and eigth rays are recovered by sharp tubercules Absent Spillmann, 1961
Barbatula barbatula The second ray is enlarged and longer and sharp tubercules on second and sixth rays of pectoral fin Absent Bruslé and Quignard, 2001
Cobitis taenia Growth of the Canestrini organ Absent Vaino and Saat, 2003
Cobitis taenia The second ray of the pectoral fin is enlarged, and at the base of the fin (Internal face) there is a bony process with a scale-spahe calle the Canestrini organ. Pectoral fin are relatively longer Absent Spillmann, 1961
Cobitis taenia The second ray of pectoral fin is sticker and nuptial tubercles apperas on pelvic fins during breeding season Present Billard, 1997
Cobitis taenia No Absent Bohlen, 2000
Cobitis taenia The second ray of male pectoral fin is thickened and there is an enlarged scale at the base (Canestrini scale) Absent Coad, 2006
Cobitis taenia Male were identified in the field by the presence of a lamina circularis, a plate-like ossification on the base of the second pectoral fin ray. This structure de velops in males of 45-50 mm TL and is present in all males > 50 mm TL Present Bolhen and Ritterbusch, 2000
Cobitis taenia Sexual dimoprhism is clearly marked: females can be 13 cm long, males do not exceed 9 cm. The male pectoral fin is slighter because of the longer and thicker secondary ray. A blade-like osseous appendage stems from the base of the ray : it is Canestrini's organ, also known as lamina circularis Absent Lodi and Malacarne, 1990
Cobitis taenia The spined loach is a gonochoristic species with some males occassionnaly containing a small number of oocytes in their testes Absent Rasotto, 1992
Cobitis paludica Mature males exibit secondary sexual characters like the lamina circularis with a short manubrium, allowing external sex recognition Absent Perdices and Doadrio, 1977
Cobitis paludica A change of coloration is observed only during spawning activity: the male became pale [This spawning coloration. This spawning coloration disappeared within a few hours after spawning activity Absent Bohlen, 2000
Blicca bjoerkna Nuptial tubercules all over the body and first rays of pectoral fins Present Rinchard, 1996
Blicca bjoerkna When the white bream reach maturity, females grow faster than males Absent Hansen, 1980
Abramis brama Nuptial tubercules on head, fins, and sides. Colors become brighter Present Spillmann, 1961
Abramis brama Territorial males are brown-yellow in colouration with tubercules Absent Poncin, 1996
Abramis brama Males have their breeding tubercles much more intensively developped, and larger individuals have distincly more numerous tubercles than smaller Absent Witkowski and Rogowska, 1991
Abramis brama Most authors revealed that there was no secondary sexual dimorphism or that is was very weak. Males have keratinized spawning tubercles. Tubercles appear 20-30 days before spawning, and in some males may last as long as to the autumn. Tubercles are more noticeable in older males and they extend from the fish head (large tubercles) to caudal region (small ones). They are most numerous over the head and dorsal part of the body. Absent Brylinska and Boron, 2004
Alburnoides bipunctatus Nuptial tubercules, and longer paired fin Present Spillmann, 1961
Alburnoides bipunctatus Pelvic fin longer Absent Coad, 2005
Alburnus alburnus Nuptial tubercules on back and sides, and inferior fins are colored in orange at their base Present Spillmann, 1961
Alburnus alburnus During reproduction, males bears nuptial tubercules on back and sides. Besides, during that period inferior fins are orange at their bases Present Rinchard, 1996
Alburnus alburnus Nuptial tubercules on the back Present Bruslé and Quignard, 2001
Alburnus alburnus During reproduction, males bears nuptial tubercules on back and sides. Besides, during that period inferior fins are orange at their bases Present Billard, 1997
Alburnus alburnus Tubercles line the edge of each scale and in single file line the rays of all fins. Fine tubercles cover the whole head Absent Coad, 2006
Aristichthys nobilis Mature males had rough body surface and callosities on the fins Absent Santiago, 2004
Aristichthys nobilis External sexual dimorphism can be determined by examining the pectoral fins. In the male, these fins have a sharp edge along the dorsal surface of several front rays, whereas in the female this characteristic is absent. This secondary sexual characteristic of the male is formed before maturity, and once formed, persists throughout its lifetime. Males usually reach sexual maturity one year earlier than females Absent Jennigs, 1988
Aristichthys nobilis Males generally mature one year earlier and at smaller size than females Absent Schrank, 1999
Aristichthys nobilis Edges of the upper rims of several of the foremost pectoral fin rays are sharp and slant backward Absent Naca, 1989
Aspius aspius Male bears nuptial tubercles over the body, particulalry the head during the breeding season Present Billard, 1997
Aspius aspius Male bears nuptial tubercles Present Keith and Allardi, 2001
Barbus barbus Nuptial tubercles on head on on three lines on the back Present Spillmann, 1961
Barbus barbus Nuptial tubercules on head and sides Present Bruslé and Quignard, 2001
Barbus barbus Male and female barbels reach approximatively the same value of Gi in the reproductive period, hich is very uncommon in cyprinid fishes Absent Lobon-Cervia and Fernandez-Delgado, 1984
Carassius auratus Tiny white bumps on the head and around the pectoral fin Absent Horvath, 1992
Carassius auratus Male bears nuptial tubercles on head, opercules, and first rays of pectoral fins Present Billard, 1997
Carassius auratus Nuptial tubercles fune, on opercles, sometimes on back, and a few on pectotal fins of breeding males Present Scott and Crossman, 1973
Carassius auratus During spawning fish are more brightly coloured than usually. During spawning males have hish locomotor activity, they are covered with breeding tubercles especially on the head and abdomen near pectoral fins, and their general coloration changes to purple Present Sczerbowski and Szczerbowski, 1996
Carassius carassius The head and scales develop tubercules in the epithelium Absent Holopainen, 1997
Carassius carassius Nuptial tubercules on head and first rays of fins Present Spillmann, 1961
Carassius carassius Male bears nuptial tubercules over the head, opercules, and first rays of pectoral fins Present Bruslé and Quignard, 2001
Carassius carassius Male bears nuptial tubercules over the head, opercules, and first rays of pectoral fins Present Billard, 1997
Carassius carassius Males generally mature one year earlier Absent Scholfield, 2005
Carassius carassius Thre is a popular belief that crucian carp have no externally visible secondary or tertiary sexual dimorphisms. However, several authors report on higher weight of females than males at same length. Females live longer than males in the same environment. Absent Sczerbowski and Szczerbowski, 1996
Chondrostoma nasus Nuptial tubercles, the first ray of pectorals becomes thicker, pigmentation is more pronounced Present Spillmann, 1961
Chondrostoma nasus Breeding tubercules on head, entire body and fins Absent Witkowski and Rogowska, 1991
Chondrostoma nasus Tubercles occur on the head, nearly the entire body, and on all fins. In males exceeding 350 mm SL, even the anterior side of the snout is covered Absent Ahnelt and Keckeis, 1994
Chondrostoma nasus During spawning migrations and during spawning itself nase males have breeding tubercles on gill covers, scales and fins, especially on pectoral fins Absent Prawochenski, 1964
Chondrostoma toxostoma Do not seem to display any bright color Present Spillmann, 1961
Ctenopharyngodon idella Appereance of tubercles on the dorsal and medial surfaces of the pectoral fins in males Absent Cudmore and Mandrak, 2004
Ctenopharyngodon idella Males generally mature a year earlier than females Absent Scholfield, 2005
Ctenopharyngodon idella Extrnal sexual dimorphism appears in adults with the onset of maturity. Many authors have reported the presence of deciduous tubercles (pearl organs) on the dorsal and medial surfaces of the pectoral fins of male grass carp during the breeding season. Also found pearl organs on the dorsal fin and dorsum of the caudal peduncle Absent Shireman and Smith, 1983
Ctenopharyngodon idella The pectoral fin rays are thick and long, extending freely like sharp knives. In the reproduction season, pearl organs appear on the pectoral fins and opercula of mature male fish. They are coarse to the touch Absent Naca, 1989
Cyprinus carpio Develop pimples on the gills Present Mickaels, 1988
Cyprinus carpio Males bear nuptial tubercles on head and body Present Lafaille and Crivelli, 2001
Cyprinus carpio Nuptial tubercles fine and scattered Present Scott and Crossman, 1973
Cyprinus carpio The abdomen of male carp does not become obviously distended but may become darker in colour and nuptial tubercles appear on the head and on pectoral fin rays Present Smith, 2004
Gobio gobio During the spawning season, male bears nuptial tubercules Present Spillmann, 1961
Gobio gobio At spawning time, the heads of ripe male are thickly sprinkled with small nuptial tubercles like those of the dace. Nuptial tubercules also occur on the pectoral fins Present Kennedy and Fitzmaurice, 1972
Gobio gobio Bears nuptial tubercules Present Bruslé and Quignard, 2001
Gobio gobio During the spawning season, male bears nuptial tubercules on head and opercules Present Rinchard, 1996
Gobio gobio In males, tubercles are much more intensively developped than in females. In larger individuals, the whole head, trunk, and all the fins are covered by tubercules [only head for smallest] Absent Witkowski and Rogowska, 1991
Gobio gobio Male bears nuptial tubercles on head Present Billard, 1997
Gobio gobio During the spawning season, male bears nuptial tubercules Present Rossechi and Kestemont, 2001
Hypophthalmichthys molitrix There is a row of fine bony atenoid serrations on several of the foremost fin rays of the pectoral fin. They are coarse and thorny and present throughout the life of the fish* Present Naca, 1989
Leucaspius delineatus Prominent nuptial tubercles on the dorsal head surface, snout, on the lower jaw in three pairs on the upper jaw in two pairs for a total of about 60 tubercules. The genital opening is depressed Present Coad, 2005
Leucaspius delineatus Nuptial tubercles on male at maturity Present Billard, 1997
Leucaspius delineatus Reproducing males have white spawing tubercles characteristic of many male cyprinids in spawning condition Absent Bonislawska, 1999
Leuciscus cephalus Male bears nuptial tubercles Present Bruslé and Quignard, 2001
Leuciscus cephalus Male bears nuptial tubercles on head and opercules Present Changeux and Le Louarn, 2001
Leuciscus cephalus Fin rays of some chub individuals are intensively coloured during spawning Absent Zelepien, 1997
Leuciscus idus Yellowish or white breeding tubercles apear in males during the spawning on the anterior part of the head Absent Witkowski, 1997
Leuciscus leuciscus Bears whitish nuptial tubercules on snout, head, cheeks, opercules, sides and belly. Pectoral fin are longer in male than female Present Spillmann, 1961
Leuciscus leuciscus Male bears whitish nuptial tubercule Absent Bruslé and Quignard, 2001
Leuciscus leuciscus Breeding tubercles are present on the head, trunk, and pectoral fin Present Witkowski and Rogowska, 1991
Mylopharyngodon piceus The pectoral fin rays are thick and long, extending freely like sharp knives. In the reproduction season, pearl organs appear on the pectoral fins and opercula of mature male fish. They are coarse to the touch Absent Naca, 1989
Phoxinus phoxinus Bear nuptial tubercules on head, and bright colours Present Spillmann, 1961
Phoxinus phoxinus Nuptial color: male are much clearer than female : blue-black back and red belly Absent Bruslé and Quignard, 2001
Phoxinus phoxinus Breeding tubercles are more developped in males than females, covered the head, trunk, some on pectoral fins Absent Witkowski and Rogowska, 1991
Phoxinus phoxinus Spawning colours and well-developed tubercles Absent Mills, 1987
Phoxinus phoxinus Before spawning, the sexual dimorphism becomes more evident, a nuptial colouration develops: the dorsal side of male becomes dark blue-blackish, the ventral slight red, small pointed white breeding tubercles occur on the upper side of head and of body Absent Papadopol and Weinberger, 1975
Phoxinus phoxinus Pectoral and ventral fins are larger and stouter in males. These traits almost always allow to determine sex in the minnow older than 3 years, before the fish is dissected. Additionnally, the spawning fish show nuptial (pearly tubercles) on their foreheads, the trait again being strouger in males. Singular pearly tubercles may appear also on the sides of the body. The spawning coloration is different in both sexes as well, the males bearing more intensive colours: the dorsal side is occsionally almost black, and the pectoral and ventral fins, particularly in their basal part, are bright red. The male show a red coloration on the basal part of the pectoral, ventral and anal fins Present Heese, 1984
Phoxinus phoxinus Characterisitic of the minnow is a spawning livery which is particularly marked in males and to a lesser degree in females. During the spawning period the head of the fish is covered with tubercles, represented by sharp conical epithelial formations covered in a horny substance. According to our observations tubercles are characteristic mainly in male, in females tubercles are rarely encountered and ten to be weakly expressed. During the spawning period the coloration of the fish also changes in both males and females, but in the latter these changes are less marked. The dorsum of the males become darked, the sides acquire an intensive yellow-green, more frequently adark-green color... Present Soin, 1982
Phoxinus phoxinus In the male the pectoral fin is broad and rounded, i.e. fan shaped, whereas in the female it is narrow and weakly rounded. Also observed that the first eight fin rays of the pectoral fin thickened in the male and not in the female, a character which first appears in sexually ripe individuals and remains for the rest of life. Windermere fish sowed this sexual dimorphic character well at breeding period, but outside this period it was a little less obvious, no thickening of the fin rays was seen in immature in fish. On the top of the head were a number of milk-white spinose tubercule. The female had much the same colouring of back and sides as the male, the metallic sheen of the sides being perhaps more golden and less green than the male. The head opercules were also present although, in some specimens, much less bodly developed. The breeding coloration in the male is weakly suggested as early as mid-March, but neither male nor female have head tubercles at this time. in both sexes the tubercles are lost after spawning and a tiny hole on the head marks their place Present Frost, 1943
Phoxinus phoxinus During the spawning season, males displayed a bright coloration all over the body and bear nuptial tubercles over the head Present Kestemont and Mélard, 1994
Pimephales promelas Bears breeding tubercles Absent Gale and Buynak, 1982
Pimephales promelas The largest male displayed nutpial tuberculs and the typical breeding color pattern, whereas the smaller male displyed tubercules but had the female color pattern Absent DeWitt, 1993
Pimephales promelas Nuptial tubercles in reproductively-active male Present Jensen, 2001
Pimephales promelas Secondary sex characters were noted on the males approximatively thrity days before the first eggs were deposited, thus making it easy to distinguish males from females. The appereance of pearl organs or tubercles on the head and the coloration constitute the most evident secondary sexual characters. The secondary sexual characters began to fade immediatly after the close of the spawing period and by August 27th they were very faint and nearly obliterated. Absent Markus, 1934
Pseudorasbora parva Male are darker than females and the flank has a metallic violet sheen, horny pad developps on the jaws, sharp tubercules Present Coad, 2005
Pseudorasbora parva The sharp tubercules on the head of males during spawning time serve as protection Absent Makeyeva and Mokamed, 1982
Pseudorasbora parva The sexual dimorphism becomes pronounced during spawning. In males breeding tubercles appear on the head. The greatest accumulation of sharp tubercles is located in the anterior part of the head, on the frons, near nostrils and below and above the eye. Few tubercles are observed also on the lower lip. In that period the males darken distinctly, and their fins become black while the operculum gets violet Absent Witkowski, 2006
Pseudorasbora parva Males were significantly larger than females Absent Katano and Maekawa, 1997
Rhodeus sericeus Develop bright nuptial coloration Present Smith, 2004
Rhodeus sericeus Breeding tubercles only in males, only on the head Absent Witkowski and Rogowska, 1991
Rutilus rutilus Nuptial tubercules on head, snout, sides of the head, fins Present Spillmann, 1961
Rutilus rutilus Numerous nuptial tubercules on head, snout, sides of the head, fins Present Rinchard, 1996
Rutilus rutilus Tubercules cover both head, body sides and fins Absent Witkowski and Rogowska, 1991
Rutilus rutilus Male bears nuptial tubercles all over the body, and particularly on the anterior part Present Le Houarn, 2001
Rutilus rutilus Have secondary sexual ornements, breeding tubercles, that are keratin-based epidermal nodules which are common in males of several fish taxa Absent Kort, 2004
Rutilus rutilus All the males studied, including the ones with no breeding tubercles, were sexually mature and ready to spawn Absent Kortet, 2004b
Scardinius erythrophthalmus Nuptial tubercules on head and back Present Spillmann, 1961
Scardinius erythrophthalmus Male bears nuptial tubercles on head and back Present Lafaille, 2001
Tinca tinca Two lateral thickning sysmetric of the muscle wall, located just behind and above the insertion of the pelvic fin Absent Spillmann, 1961
Tinca tinca Diploid males have longer pelvic fins than diploid females, with bulky first fin rays, and covering the anus in every case Absent Linhart and Billard, 1995
Tinca tinca In contrast to females, tench Tinca tinca (L.) males have large pelvic fins with a thickened and bent second ray. Males also produce notable ventral protuberances during breeding, but the function of these male ornaments is not known Absent Vainikka, 2005
Vimba vimba A well-expressed spawning livery, the appearance of black stripes along the dorsal and ventral part of the body is usually observed in ripe males Absent Shikhshabekov, 1979
Vimba vimba The males become black on the back, reddish on the belly, their fins become red and the tips of the dorsal and caudal fins become dark, and they develop minute tubercles on the body during the spawning season Absent Coad, 2005
Vimba vimba Brighter colors of males, brown sides and red belly Present Billard, 1997
Vimba vimba Take on mating colours, the dorsal part and sides becoming navy-blue and the fins and some ventral parts assuming and intensive colour. As a rule, after each migration, especially one connected with spawning, the runs swims back to the reservoir. Absent Wajdowicz, 1974
Gambusia affinis Internal fertilization is possible because the anal fin is modified into a copulatory organ Absent Fishbase, 2006
Gambusia affinis Nine females and two mature males, as determined by the number of segments in the third ray of the gonopodium Absent Medlen, 1951
Gambusia affinis The anal fin of the adult male is modified into a long and slender intromittent organ, the gonopodium, which the male can extend at various angles and directions from the body Absent Martin, 1975
Lota lota GSI in burbot is higher for the testes than the ovaries !!! Absent Brylinska, 2002
Gasterosteus aculeatus Male exhibits breeding color at ca. 12°C and retain their color for a month after spawning season: brilliant, dark green and orange-red spawning coloration Absent Internet, 2005
Gasterosteus aculeatus Breeding males develop a red belly and throat, blue sides, light blue back and have bright blue or turquoise eyes Present Coad, 2005
Gasterosteus aculeatus Breeders displayed a well-developed nuptial colloration and aggressive behavior Absent Sokolowska and Sokolowska, 2006
Ambloplites rupestris During spawning the male's body darkens, resulting in a pitch-black male contrasting sharply beside the unchanged female Absent Gross and Nowell, 1980
Lepomis gibbosus Brilliant green to organe-red spawning coloration of males Absent Internet, 2005
Lepomis gibbosus Males matured at a larger size than females in both lakes Absent Deacon and Keast, 1987
Micropterus salmoides Externally bass greater than 35 cm in total length could be sexed correctly 92 percent, in male the scaleless area surrounding and immediately adjacent to the urogenital opening is nearly circular in shape Absent Heidinger, 1976
Micropterus salmoides In the male, the genital papilla is usually conical (swollen)and red in color Absent Newburg, 1975
Micropterus salmoides The urogenital opening in male is nearly circular Absent Williamson, 1993
Micropterus salmoides The genital papilla method (i.e.the presence on females and the absence on males of a genital papilla, a redish protuberance surronding the urogenital papilla) was successufl during the spring but only 48% successful during the fall. The shape of the urogenital opening (round in males, ovale in females) was a poor indicator of sex (53% of the fish were sexed correctly). Probing the urogenital opening was the best single method, it provided success rates of 90% (probe depth) and 94/ (probe length) Absent Benz and Jacobs, 1986
Micropterus salmoides No nuptial tubercles but colours darken on spawning males Absent Scott and Crossman, 1973
Morone americana No external characteristics have been found that help to differentiate between the two sexes, except during the spawning season. At that time, the sex of mature white perch is determined by applying pressure to the abdomen and noting the sexual products forced from the urogenital aperture Absent Mansuetti, 1961
Morone chrysops Urinary and genital pores are united in males Absent Internet, 2005
Perca flavescens Colours of spawning males more intense, bronze-green, bars darker, lower fins suffused with orange to bhroght red Present Scott and Crossman, 1973
Perca fluviatilis Males at spawning are generally brighter in colour Present Thorpe, 1977
Sander lucioperca According to Hungarian aquaculturists sexually mature pike-perch can be sexed on the basis of external features, males have a darker abdomen than the females, and females show a white rounded belly, a broader head, and a higher back than males. In our experiments in early spring, these criteria proved to be unreliable Present Schlumberger and Proteau, 1996
Sander vitreus No Absent Colby, 1979
Coregonus lavaretus May bear rows of elongate tubercules on the scales Absent Coad, 2006
Coregonus clupeaformis Whitefish males commonly develop breeding tubercles, especially on the flanks, but tubercles are less well developped and rarer on females Absent Willson, 1997
Coregonus clupeaformis Nuptial tubercles on the head Present Mack and Billard, 1984
Hucho hucho Breeding tubercles present Present Kratt and Smith, 1978
Hucho hucho The males undergo marked colour changes, turning red or copper-red Absent Prawochensky and Kolder, 1968
Hucho hucho Males are bigger than females Absent Fleming, 1998
Oncorhynchus gorbuscha Marked hump and a large kype, colour changes Absent Groot, 1996
Oncorhynchus gorbuscha Males have larger heads, thicker caudal peduncles, longer bases of the anal and dorsal fin Absent Beacham, 1988
Oncorhynchus gorbuscha Male pink salmon normally develop a pronouced hump, but males adopting a satellite-male mating tactic have only a small hump [In Salmo, most Salvelinus, and most Oncorhynchus, a major sexual difference is found in the development, in normal breeding individuals, of elongated, hooked jaws with enlarged teeth.An upturned lower jaw is technically called a kype, an enlarged and often distorted upper jaw is termed a snout.Kype and sount development differs not only among individuals but also among species and conspecific populations: it is generally greater in stream-dwelling and anadromous forms than in lake-spawning or strickly freshwater forms.Kypes andsnouts are best developed in males, although females of some species also develop smaller ones. Another secondary trait is a hump anterior to dorsal fin, found especially in males.] Present Willson, 1997
Oncorhynchus gorbuscha "At one extreme are the biggest males with greatly enlarged snout (Kype) and dorsal hump (hence the name ""humpback"" for this species). The kype with its large teeth is used to ram and bite other males, similar snout development and associated aggressive behaviour are found in other salmonids. The considerable dorsal hump development, however, is unique to pink salmon, and as the largest males are consitently closest to the female in the group of males associated with har at spawning, the greatly enlarged hump also contributes to dominance amon males. At the other extreme are the smallest males, who resemble females in size, shape, and colour. " Absent Keenleyside and Dupuis, 1988
Oncorhynchus gorbuscha Males are bigger than females Absent Fleming, 1998
Oncorhynchus keta The mature male is distinguished from the mature female by a hooked snout and more fanglike teeth Absent Bakkala, 1970
Oncorhynchus keta Breeding males develop hooked jaws and large teeth and a slight hump in front of the dorsal fin Absent Coad, 2006
Oncorhynchus keta In Salmo, most Salvelinus, and most Oncorhynchus, a major sexual difference is found in the development, in normal breeding individuals, of elongated, hooked jaws with enlarged teeth.An upturned lower jaw is technically called a kype, an enlarged and often distorted upper jaw is termed a snout.Kype and sount development differs not only among individuals but also among species and conspecific populations: it is generally greater in stream-dwelling and anadromous forms than in lake-spawning or strickly freshwater forms.Kypes andsnouts are best developed in males, although females of some species also develop smaller ones. Another secondarytrait is a hump anterior to dorsal fin, found especially in males. Present Willson, 1997
Oncorhynchus keta Males had larger heads, thicker caudal peduncles, and larger dorsal fins than females, but females had larger anal fins than males Absent Beacham and Murray, 1987
Oncorhynchus keta Males bigger than females Absent Fleming, 1998
Oncorhynchus kisutch In Salmo, most Salvelinus, and most Oncorhynchus, a major sexual difference is found in the development, in normal breeding individuals, of elongated, hooked jaws with enlarged teeth.An upturned lower jaw is technically called a kype, an enlarged and often distorted upper jaw is termed a snout.Kype and sount development differs not only among individuals but also among species and conspecific populations: it is generally greater in stream-dwelling and anadromous forms than in lake-spawning or strickly freshwater forms.Kypes andsnouts are best developed in males, although females of some species also develop smaller ones. Another secondarytrait is a hump anterior to dorsal fin, found especially in males. Present Willson, 1997
Oncorhynchus kisutch Males are bigger than females Absent Fleming, 1998
Oncorhynchus mykiss No nuptial tubercles but minor changes to head, mouth, and color especially in spawning males Absent Scott and Crossman, 1973
Oncorhynchus mykiss Breeding males have an elongated snout, the lower jaw is hooked and the roof of the mouth is white Present Coad, 2006
Oncorhynchus mykiss In Salmo, most Salvelinus, and most Oncorhynchus, a major sexual difference is found in the development, in normal breeding individuals, of elongated, hooked jaws with enlarged teeth.An upturned lower jaw is technically called a kype, an enlarged and often distorted upper jaw is termed a snout.Kype and sount development differs not only among individuals but also among species and conspecific populations: it is generally greater in stream-dwelling and anadromous forms than in lake-spawning or strickly freshwater forms.Kypes andsnouts are best developed in males, although females of some species also develop smaller ones. Another secondarytrait is a hump anterior to dorsal fin, found especially in males. Present Willson, 1997
Oncorhynchus mykiss Males are bigger than females Absent Fleming, 1998
Oncorhynchus nerka Hump size in sockeyes differ greatly among populations. Male mating success within some sockeye populations is positively correlated with hump size[In Salmo, most Salvelinus, and most Oncorhynchus, a major sexual difference is found in the development, in normal breeding individuals, of elongated, hooked jaws with enlarged teeth.An upturned lower jaw is technically called a kype, an enlarged and often distorted upper jaw is termed a snout.Kype and sount development differs not only among individuals but also among species and conspecific populations: it is generally greater in stream-dwelling and anadromous forms than in lake-spawning or strickly freshwater forms.Kypes andsnouts are best developed in males, although females of some species also develop smaller ones. Another secondarytrait is a hump anterior to dorsal fin, found especially in males.] Present Willson, 1997
Oncorhynchus nerka Males are bigger for both resident and anadromous populations Absent Fleming, 1998
Oncorhynchus tshawytscha In Salmo, most Salvelinus, and most Oncorhynchus, a major sexual difference is found in the development, in normal breeding individuals, of elongated, hooked jaws with enlarged teeth.An upturned lower jaw is technically called a kype, an enlarged and often distorted upper jaw is termed a snout.Kype and sount development differs not only among individuals but also among species and conspecific populations: it is generally greater in stream-dwelling and anadromous forms than in lake-spawning or strickly freshwater forms.Kypes and snouts are best developed in males, although females of some species also develop smaller ones. Another secondary trait is a hump anterior to dorsal fin, found especially in males. Present Willson, 1997
Oncorhynchus tshawytscha Males are bigger than females Absent Fleming, 1998
Salmo salar Male change colour and shape, the male more pronounced than female: become tusty-brown on the sides and yellowish brown on th back and head. The head of male elongates and the lower jaw becomes enlarged and develops a hook of kype Present Groot, 1996
Salmo salar As the adults prepare for spawning, the head of the male undergoes transformation, the head elongates and the lower jaw becomes enlarged and hooked at the tip, forming a kype Present Scott and Crossman, 1973
Salmo salar In Salmo, most Salvelinus, and most Oncorhynchus, a major sexual difference is found in the development, in normal breeding individuals, of elongated, hooked jaws with enlarged teeth.An upturned lower jaw is technically called a kype, an enlarged and often distorted upper jaw is termed a snout.Kype and sount development differs not only among individuals but also among species and conspecific populations: it is generally greater in stream-dwelling and anadromous forms than in lake-spawning or strickly freshwater forms.Kypes andsnouts are best developed in males, although females of some species also develop smaller ones. Another secondarytrait is a hump anterior to dorsal fin, found especially in males. Present Willson, 1997
Salmo salar Male bigger than female Absent Fleming, 1998
Salmo trutta fario Weak [See for details] Absent Coad, 2006
Salmo trutta fario In Salmo, most Salvelinus, and most Oncorhynchus, a major sexual difference is found in the development, in normal breeding individuals, of elongated, hooked jaws with enlarged teeth.An upturned lower jaw is technically called a kype, an enlarged and often distorted upper jaw is termed a snout.Kype and sount development differs not only among individuals but also among species and conspecific populations: it is generally greater in stream-dwelling and anadromous forms than in lake-spawning or strickly freshwater forms.Kypes andsnouts are best developed in males, although females of some species also develop smaller ones. Another secondarytrait is a hump anterior to dorsal fin, found especially in males. Present Willson, 1997
Salmo trutta fario Male bigger than female Absent Fleming, 1998
Salmo trutta fario Once the large males, ('hooknoses', males which showed a kype on the lower jaw and Lt > 300 mm) entered Själsöan, they generally occupied a territory where they stayed. In contrast, small males ('sneakers', males without a kype on the lower jaw, and Lt> 300 mm) did not have any specific territorty and moved frequently up and downstream Present Rubin, 2005
Salvelinus alpinus Bright colors on sides and pair and impair fins Present Spillmann, 1961
Salvelinus alpinus In Salmo, most Salvelinus, and most Oncorhynchus, a major sexual difference is found in the development, in normal breeding individuals, of elongated, hooked jaws with enlarged teeth.An upturned lower jaw is technically called a kype, an enlarged and often distorted upper jaw is termed a snout.Kype and sount development differs not only among individuals but also among species and conspecific populations: it is generally greater in stream-dwelling and anadromous forms than in lake-spawning or strickly freshwater forms.Kypes andsnouts are best developed in males, although females of some species also develop smaller ones. Another secondarytrait is a hump anterior to dorsal fin, found especially in males. Present Willson, 1997
Salvelinus alpinus Only large males may be strong enough to flaunt bright red spawning colors and still defend a territory Present Jonsson and Hindar, 1982
Salvelinus alpinus Males are bigger than females Absent Fleming, 1998
Salvelinus fontinalis Male developp a small kype on the lower jaw Present Groot, 1996
Salvelinus fontinalis Spawning males develop a hooked lower jaw or kype Present Coad, 2006
Salvelinus fontinalis Pectoral and pelvic fins are longer in male than female brook char. [In Salmo, most Salvelinus, and most Oncorhynchus, a major sexual difference is found in the development, in normal breeding individuals, of elongated, hooked jaws with enlarged teeth.An upturned lower jaw is technically called a kype, an enlarged and often distorted upper jaw is termed a snout.Kype and sount development differs not only among individuals but also among species and conspecific populations: it is generally greater in stream-dwelling and anadromous forms than in lake-spawning or strickly freshwater forms.Kypes andsnouts are best developed in males, although females of some species also develop smaller ones. Another secondary trait is a hump anterior to dorsal fin, found especially in males.] Present Willson, 1997
Salvelinus fontinalis There is some evidence that male matures earlier in the season than the females do Absent Wydoski and Cooper, 1966
Salvelinus fontinalis Males bigger than females Absent Fleming, 1998
Salvelinus namaycush Male lake char are capable of developing a kype, but they almost never do. Male lake char may be more iridescent than females, sport a black lateral stripe, or develop (in soem populations) breeding tubercles, but generally they show less sexual dimoprhism than other char do [In Salmo, most Salvelinus, and most Oncorhynchus, a major sexual difference is found in the development, in normal breeding individuals, of elongated, hooked jaws with enlarged teeth. An upturned lower jaw is technically called a kype, an enlarged and often distorted upper jaw is termed a snout. Kype and sount development differs not only among individuals but also among species and conspecific populations: it is generally greater in stream-dwelling and anadromous forms than in lake-spawning or strickly freshwater forms.Kypes and snouts are best developed in males, although females of some species also develop smaller ones. Another secondarytrait is a hump anterior to dorsal fin, found especially in males.] Present Willson, 1997
Salvelinus namaycush Breeding tubercles present Present Kratt and Smith, 1978
Salvelinus namaycush Males are bigger than females Absent Fleming, 1998
Stenodus leucichthys Males develop tubercles on the head and sides of the abdomen during spawning Absent Coad, 2006
Thymallus thymallus Grayling males are brighter than females, sometimes larger, and have longer dorsal and pelvic fins Present Willson, 1997
Thymallus arcticus No nuptial tubercles and none of the body changes so characteristic of salmonids at spawning time, but colours darken and the males become more brilliant than the females Absent Scott and Crossman, 1973
Thymallus arcticus Territory-holding dish in their study had a different color, the flanks and back becoming a brownish or dark grey, while the tip of the nose in many specimens became white Absent Bishop, 1971
Thymallus arcticus Seasonnal occurrence of tubercles on breeding male and female. Male tubercles, knob-like structures located on the anterior portion of the scale. Female tubercles were less sharply defined, covering most of the surface of the affected scales Absent Kratt and Smith, 1978
Cottus gobio Males are deadily distinguished at spawning time by their dark colouration, a cremy dorsal edge to the first dorsal fin, and protruding genial papillae Absent Tomlinson and Perrow, 2003
Ameiurus nebulosus No nuptial tubercles Absent Scott and Crossman, 1973
Ictalurus punctatus Male assumes a darker body coloration with thick lips Present Internet, 2005
Ictalurus punctatus Males at bredding time often brighter blue than otherwise Present Scott and Crossman, 1973
Ictalurus punctatus Changes in the external features of sexually active channel catfish occur primarily in males: these changes include widening of the head, increased subcutaneous tissue on dorsal head, and darker skin color. Present Grizzle, 1985
Ictalurus punctatus Males were 18 to 43% heavier than females Absent Alp, 2004
Ictalurus punctatus Secondary sexual characteristics are strongly pronounced. Mature males display a broad, muscular head wider than the body and thickened lips, while head of females remains slender Absent Legendre, 1997
Silurus glanis Sexual dimorphism is not very pronounced. Females have a comparatively more oval, convex and blunt genital papilla, while male present a more conical papilla and a brush part on the first spin ray of the pectoral fin, but difficulty on distinguishing differences may lead to erros in sexing Absent Legendre, 1997
Silurus glanis Males grew 2 to 15% faster than females Absent Alp, 2004