the crevalle jack , caranx hippos ( also known as the common jack , black-tailed trevally , couvalli jack , black cavalli , jack crevale and yellow cavalli ) is a common species of large marine fish classified within the jack family , carangidae .

the crevalle jack is distributed across the tropical and temperate waters of the atlantic ocean , ranging from nova scotia , canada to uruguay in the west atlantic and portugal to angola in the east atlantic , including the mediterranean sea .

it is distinguishable from similar species by its deep body , fin colouration and a host of more detailed anatomical features , including fin ray and lateral line scale counts .

it is one of the largest fish in the genus caranx , growing to a maximum known length of 124 cm and a weight of 32 kg , although is rare at lengths greater than 60 cm .

the crevalle jack inhabits both inshore and offshore waters to depths of around 350 m , predominantly over reefs , bays , lagoons and occasionally estuaries .

young fish dispersed north by currents in the eastern atlantic are known to migrate back to more tropical waters before the onset of winter ; however , if the fish fail to migrate , mass mortalities occur as the temperature falls below the species ' tolerance limits .

the crevalle jack is a powerful , predatory fish , with extensive studies showing the species consumes a variety of small fish , with invertebrates such as prawns , shrimps , crabs , molluscs and cephalopods also of minor importance .

dietary shifts with both age , location and season have been demonstrated , which led some researchers to postulate the species is indiscriminant in its feeding habits .

the crevalle jack reaches maturity at 55 cm in males and 66 cm in females , with spawning taking place year round , although peaks in activity have been documented in several sites .

the larval and juvenile growth has been extensively studied , with the oldest known individual 17 years of age .

the crevalle jack is an important species to commercial fisheries throughout its range , with annual catches ranging between 1000 and 30 000 tonnes over its entire range .

it is taken by a variety of netting methods , including purse nets , seines and gill nets , as well as hook-and-line methods .

the crevalle jack is also a revered gamefish , taken both by lures and bait .

the species is considered of good to poor quality table fare , and is sold fresh , frozen , or preserved , or as fishmeal or oil at market .

the crevalle jack is closely related to both the pacific crevalle jack and the longfin crevalle jack , the latter of which has been extensively confused with the true crevalle jack until recently .

crevalle jack

raw cubes of jack crevalle are ready to be marinated with a variety of ingredients for chef chris sherrill’s jack crevalle prime rib with horseradish white bbq sauce .
the crevalle jack will often grunt or croak when it is caught by fishermen .
the crevalle jack has edible flesh , but is not considered very desirable for food .
raw cubes of marinated jack crevalle are prepared for kabobs , skewered on rosemary sprigs .
this article is a species account for crevalle jack ( caranx hippos ) in florida .
averaging 3 to 5 pounds in weight and 1 to 21⁄2 feet in length , the crevalle jack can regularly weigh as much as 10 pounds ; the paciﬁc crevalle jack is usually smaller . the all - tackle world record for the crevalle jack is a 58 - pound angolan ﬁsh and for the paciﬁc crevalle jack is a 39 - pound costa rican ﬁsh .
reproductive behavior of the bigeye crevalle jack caranx sexfasciatus : . . . | download scientific diagram
the florida fishing record for the crevalle jack is 23 . 1 kg ( 51 lbs ) .
known as the horse - eye jack or horse - eye crevalle in reference to the large eyes of the species . other lesser used names include big - eye jack and false jack .
we cut the jack crevalle loins into 1 . 5 - inch - by - 1 . 5 inch cubes .
the crevalle jack is capable of producing croaking sounds by grinding its teeth together while releasing gas from its air bladder .
, inhabits the pyloric junction or the entire length of the intestine . copepods are also common parasites to the crevalle jack including
chef ' s corner : who says jack crevalle is inedible ? chef chris sherrill took a load of thought - inedible jack crevalle from the recent flora - bama fishing rodeo and whipped up some tasty kabobs . check out this story on urltoken urltoken
common jack , crevally , toro , trevally , horse crevalle ; spanish : cavallo , chumbo , cocinero , jurel común .
try this recipe for smoked jack crevalle on your next jack crevalle and let us know what you think . my fishing buddies tried this and could not believe it was jack crevalle . check out our amazon store here : urltoken become a patreon urltoken learn how to smoke small fish here : urltoken see us on facebook here : urltoken basic smoked fish recipe is here : urltoken
throughout its lifetime , the crevalle jack lives from the shoreline to open waters in the gulf of mexico - - moving in and out annually .
chef chris sherrill took a load of thought - inedible jack crevalle from the recent flora - bama fishing rodeo and whipped up some tasty kabobs .
the horse - eye jack , caranx latus , is a gamefish and minor commercial fish in the family carangidae . it is also known as the big - eye jack , and is similar in appearance to the crevalle jack , although the head of the horse - eye jack is not as blunt . the horse - eye jack is known to feed on smaller fish and on many invertebrates , such as shrimp and crab .
predators the crevalle jack is prey for many surface feeding carnivores , such as finfish including the striped marlin ( tetrapturus audax ) , and sea birds .
the crevalle jack , caranx hippos . illustration by diana rome peebles 1998 . courtesy of florida fish and wildlife conservation commission , division of marine fisheries .
…game fish , such as the crevalle jack ( c . hippos ) of warm atlantic waters and the yellow jack ( c . bartholomaei ) , which frequents warm atlantic waters and is noted for its golden - yellow sides and fins .
to plate , stack the jack crevalle kabobs on your favorite platter or plate . drizzle your horseradish bbq sauce along the kabobs and leave dollops on the plate .
hoff jg . 1971 . mass mortality of the crevalle jack , caranx hippos ( linnaeus ) on the atlantic coast of massachusetts . chesapeake science 12 : 49 .
the crevalle jack is a diurnal predator . adults prey upon on a variety of fish , shrimp and invertebrates . juveniles feed mainly on small fish and crustaceans .
parasites parasites of the yellow jack include the copepods caligus chorinemi and caligus robustus .
food habits the crevalle jack is a diurnal predator . adults prey upon on a variety of fish , shrimp and invertebrates . juveniles feed mainly on small fish and crustaceans .
shipp and i both identify jack crevalle as extremely bloody , due to their powerful swimming habits . but you know what else is deemed red and somewhat bloody ? beef !
the crevalle jack is a prey item for various surface - feeding carnivores , such as finfish ( i . e . striped marlin , tetrapturus audax ) and sea birds .
the adult horse - eye jack commonly swims with others in a school , either as one species or mixed with crevalle jack . sometimes it also swims as a pair with a member of a very different species , such as halichoeres radiatus , a type of wrasse .
as noted , we treated the jack crevalle just like beef . the outcome ?
absolutely mind - numbing and incredible ,
according to gary finch of the famed gary finch outdoors .
after forsskål’s initial description and naming , the species was independently renamed three times as caranx lessonii , caranx ekala and carangus hippoides , all of which are now considered invalid junior synonyms . [ 6 ] the latter of these names once again highlighted the similarity with the crevalle jack , with the epithet hippoides essentially meaning ‘like carangus hippos’ , [ 7 ] which was the crevalle jack’s latin name at that point in time . despite the resemblance with the crevalle jack , the two species have never been phylogenetically compared , either morphologically or genetically , to determine their relationship .
saloman ch , sp naughton . 1984 . food of crevalle jack ( caranx hippos ) from florida , louisiana , and texas . noaa technical memorandum nmfs - sefc - 134 . 34pp .
the crevalle jack is a relevantly unimportant commercial fish species . never the less , they are fished commercially throughout the year in southwest florida , and in the spring , fall , and summer in the gulf of mexico . crevalle jacks are an important sport fish , and are exploited throughout their range . they are the most common large jack caught off the west coast of florida .
this later revision in classification saw the species moved to the genus caranx , where it has remained . [ 4 ] even after its initial description , the giant trevally ( and the bigeye trevally ) were often confused with the atlantic crevalle jack , caranx hippos , due to their superficial similarity , which led to some authors claiming the crevalle jack had a circumtropical distribution . [ 5 ]
wiggers r . 2005 . crevalle jack . in : comprehensive wildlife conservation strategy . south carolina department of natural resources , columbia , sc . available : urltoken . accessed : september , 2009 .
there is a prominent black spot on the gill cover and another at the base of each pectoral ﬁn . the soft dorsal and anal ﬁns are almost identical in size . the two species are distinguished externally from each other only by the presence of a larger maximum number of scutes , up to 42 on the paciﬁc crevalle jack , as opposed to 26 to 35 on the crevalle jack .
the bluethroat pikeblenny is among the many prey items of the yellow jack . photo © suzan meldonian
this work was done on a medium - sized ( about 20 pounds ) , extremely fresh jack .
dentition the crevalle jack has three paired patches of small villiform teeth located dorsally . these teeth are larger than the premaxillary teeth . ventrally , the jack crevalle has a single pair of triangular patches of smaller teeth . these teeth , in combination with the air bladder , are responsible for the croaking noise it makes when it is caught . the fish rasp their upper and lower teeth together , this combined with air bladder resonance , are the factors contributing to the sound .
the closely related horse - eye jack ( caranx latus ) is frequently seen schooling over reefs . photo courtesy noaa
although the crevalle jack is a relevantly unimportant commercial fish , it is fished commercially throughout the year in southwest florida , and in the spring , fall , and summer in the gulf of mexico . it is an important sport fish , and is exploited throughout its range . it is the most common large jack caught off the west coast of florida .
figure 7 . reproductive behavior of the bigeye crevalle jack caranx sexfasciatus : ( a ) pairs of jacks leaving a spawning aggregation , showing both normal and dark phase ; ( b ) a pair of c . sexfasciatus swimming prior to spawning .
yep , i said it ; jack crevalle , deemed inedible by most locals . even the crabs in the crab traps turn their nose up at it . i ' ll admit , between a dare and pure curiosity , i had my doubts .
in another mixing bowl , add the ranch dressing , worcestershire sauce , garlic , scallions , lemon juice , pepper , salt blend and rosemary , and mix together . add the jack crevalle cubes and let marinate for a minimum of one hour .
adult horse - eye jack are typically dark blue to silvery - blue above , becoming silvery white to golden below .
horse - eye jack ( caranx latus ) other names : bigeye jack , ojo gordo range : all florida , especially south florida–but more common in the bahamas and caribbean . habitat : more of an openwater species than the crevalle , it is found over the reefs and near the beaches ; also in channels and harbors . description : similar in body shape to the crevalle , but the head is not quite so blunt . the color is also different , being usually silvery on the sides and below ; dark gray or blackish above . the fins are blackish as opposed to the yellow tinge of the crevalle . hard scutes forward of tail . as the name indicates , the eyes are very large . size : commonly caught in similar sizes to the crevalle , but does not grow so large , topping out at 20 pounds or so . world and florida records 24 pounds , 8 ounces . food value : poor by most tastes , and has been implicated in ciguatera poisoning ( see introduction ) . game qualities : like the crevalle , a tough brawler . tackle and baits : see jack crevalle . fishing systems : casting ; drifting ; trolling .
the crevalle jack ' s range consists mainly of the coastal areas of the western atlantic ocean from novia scotia to uruguay . they also often are found throughout the gulf of mexico , especially along the coast of texas and the west coast of florida .
over a hot grill , place your jack crevalle kabobs over hot and high heat to get the grill marks and char going . drizzle the kabobs with the butter as they sear . flames will likely occur and will char the the rosemary , but this adds a great flavor . we cooked the kabobs to medium . a little pink is perfect , as the jack can dry out .
my opinion ? it was very similar to ribeye , or even filet mignon — very flavorful , very meaty and quite wonderful . i will continue to pursue jack crevalle , and will make more efforts to cook this sustainable and available fish every chance i get .
similar species : blue runner , c . crysos ( lack black spot at base of pectoral fins ) ; other jack species .
caranx itself is part of the larger jack and horse mackerel family carangidae , a group of percoid fishes in the order perciformes .
although the crevalle jack is a relevantly unimportant commercial fish , it is fished commercially throughout the year in southwest florida , and in the spring , fall , and summer in the gulf of mexico . it is an important sport fish , and is exploited throughout its range .
this is the only jack with a black spot on pectoral fins and a scaleless chest with small patch of scales by pelvic fins .
jack crevalle is a beast when it comes to hook and line catch . in his
guide to fishes of the gulf of mexico ,
dr . bob shipp describes them best as
packs of wolves foraging for bait fish , marauding menhaden and bringing stark fear to their prey .
i saw several hundred pounds of jack crevalle hit the scales this weekend , and i was promised them all — i even had one angler pay me to take them ! so research and development was easy , finding a
venturesome palate
outside of mine proved to be the biggest challenge .
the horse - eye jack has a body form similar to other large jacks found throughout its range , with a moderately compressed elongate and deep body .
mcbride rs , ka mckown . 2000 . consequences of dispersal of subtropically spawned crevalle jacks , caranx hippos , to temperate estuaries . fish bull 98 : 528 - 538 .
crevalle jack juveniles : a . 15 . 3 mm , b . 20 . 4 mm , c . 32 . 6 mm , d . 80 . 5 mm ( standard lengths ) . images courtesy berry ( 1959 ) in development of fishes of the mid - atlantic bight , u . s . fish and wildlife service
the crevalle jack has a body depth of about three times its fork length . it has large eyes . the chest is scaleless except for a small patch of scales in front of the pelvic fins . this patch is apparent by the time the fish reaches a fork length of 0 . 98 inches ( 2 . 5 cm ) . the crevalle jack is the only jack in the western atlantic ocean with this patch of scales . there is an oval black spot on the pectoral fins ; this appears at about 4 . 72 inches ( 12 . 0 cm ) . between the seventh and the eighth spines of the adult there is an overgrowth of skin . the two most distinguishable features of this fish are the patch of scales between the pelvic fins and the oval , black spot on the pectoral fins .
the spawning season of the crevalle jack is early march to early september . spawning occurs offshore in the southeastern atlantic coast and in the gulf stream , including any associated currents . the crevalle jack has been found to spawn in both tropical and subtropical environments . the eggs of the crevalle jack are between . 03 - . 04 inches ( 0 . 7 - 0 . 9 mm ) in diameter and the newly hatched larvae are between 0 . 06 - 0 . 07 inches ( 1 . 6 - 1 . 8 mm ) in length . the larva use estuaries as nurseries . in juveniles the small patch scales on the chest form at 0 . 98 inches ( 25 mm ) . the pigmentation of the first dorsal fin decreases above 1 . 2 inches ( 30 mm ) , pigment appears on the second dorsal fin at 1 . 2 inches ( 30 mm ) , and the pelvic fin is unpigmented above 0 . 8 inches ( 20 mm ) . the pectoral spot develops at about 4 . 7 inches ( 120 mm ) .
in the western atlantic , crevalle jacks occur from nova scotia south throughout the northern gulf of mexico . in the eastern paciﬁc , they occur from san diego , california , to peru .
the maximum size of a crevalle jack is 39 . 8 inches ( 101 cm ) and 55 . 1 pounds ( 25 kg ) , however they are common to 23 . 6 inches ( 60 cm ) . after the juvenile reaches a size of 1 . 97 inches ( 5 . 0 cm ) , its growth rate increases . females are typically larger than males .
spawning occurs offshore from march through september . young ﬁsh occur in moderate to large fast - moving schools , and crevalle jacks occasionally school with horse - eye jacks , although larger ﬁsh are often solitary .
the rodeo gave me a plethora of these fish species . while lionfish was the only invasive to hit the scales , many fish species that are underutilized got some great attention . gafftopsail catfish and stingray are my favorites . sheephead and puppydrum are beginning to gain exceptional reputation for table fare , but i think the most exciting moment for me was working with and making edible jack crevalle .
the crevalle jack is found in oceanic , estuarine or riverine environments . this is influenced by the life stage of the fish . they primarily are found along the continental shelf , but occur in waters as deep as 327 feet ( 100 m ) . fish found in these deep waters are usually larger individuals . larval and juvenile jack crevalles are found in upstream currents and are common in shallow brackish waters . adults , on the other hand , usually occupy upstream currents , reefs , offshore areas or shallow inshore areas . jack crevalles live in a variety of temperatures and salinities . adults usually inhabit areas with temperatures between 64 - 92 . 5°f ( 18 - 33 . 6ºc ) of water and larvae are found in areas with temperatures between 69 - 84 . 9°f ( 20 . 4 - 29 . 4ºc ) of water . crevalle jacks have been found in fresh water to salt water environments , depending on life stage . larvae have been collected in areas with salinities between 35 . 2 - 36 . 7 parts per thousand ( ppt ) . adults have been found in freshwater habitats as well as those with a salinity of 43 . 8 ppt . they are most commonly found at salinity above 30 ppt . the crevalle jack is a pelagic fish . both adults and juveniles are usually found in schools . however , larger individuals may be found swimming the waters alone .
( linnaeus , 1766 ) ; carangidae family ; also called common jack , toro , cavally , cavalla , horse crevalle occurs in the western atlantic ocean from nova scotia , canada , to uruguay , including the gulf of mexico and occasionally in the west indies . in the eastern atlantic it is found from portugal to angola , including the western mediterranean . the crevalle jack is the common jack of in shore oceanic waters . the species apparently can tolerate a wide range of salinities and occurs around off shore reefs , in coastal waters , harbors and protected bays , over highly saline shallow flats , in brackish waters at river mouths , and has even been known to travel up coastal rivers . there is a rounded black spot at the lower base of the pectoral fin of the crevalle jack that is found in no other jacks in the area . there is also a distinct , vertically elongate black spot on the operculum . enlarged scales or scutes , numbering about 30 , extend in a line to the base of the tail fin . the similar horse - eye jack has no pectoral fin spot and 26 - 35 scutes . a voracious predator , it feeds primarily on smaller fishes , which it often chases onto beaches or against seawalls . in open water , jacks will herd bait fish into a tight mass , then rush in from all sides . the crevalle jack also feeds on shrimp and other invertebrates and on garbage dumped from boats . this superb light tackle species can be taken by spinning , fly fishing , trolling , or surfcasting . lures should be retrieved at a fast pace without pausing or stopping as jacks tend to lose interest in anything that doesn ' t act normally . most jacks are not highly valued as food , though they are edible . the small fish taste best ; larger specimens can be dark and tasteless . bleeding the fish may improve the taste . jacks are among the many species of tropical fishes , which have been implicated in ciguatera poisonings
, black cavalla , blacktailed trevally , caballi , cabalo , common jack , couvalli jack , crevelle jack , green jack , horse crevalle , horse mackerel , horse - eye jack , kingfish , trevally , and yellow cavalli . other names are carngue cravalle ( french ) , jurel comun ( spanish ) , bolchoi caranske ( russian ) , caballa ( spanish ) , camard ( french ) , carango cavallo ( italian ) , carangue crevalle ( french ) , carangue macoque ( french ) , cavalla ( spanish ) , cavalli ( french ) , charo - largo ( portuguese ) , chumbo ( spanish ) , coa ( portuguese ) , cocinero ( spanish ) , corcovado ( creole ) , couvalli ( french ) , cowreh ( krio ) , crevalle toro ( french ) , crevalle ( french ) , enforcado ( creole ) , enxareu ( portuguese ) , enxareu - macoa ( portuguese ) , grande carangue ( french ) , hevospiikkimakrilli ( finnish ) , hiraaji ( japanese ) , jejerukan ( malay ) , jiguagua ( spanish ) , jurel ( spanish ) , jurel caballo ( spanish ) , jurel cola amarilla ( spanish ) , jurel comun ( spanish ) , kanxant ( palicur ) , karang ( french ) , karanks atlantycki ( polish ) , kawre kanki ( susu ) , kokalli ( greek ) , macoa ( portuguese ) , munaguroaji ( japanese ) , paeya ( galibi ) , peixe - prussiano ( portuguese ) , prussiano ( portuguese ) , saaka ( wolof ) , sargentillo ( spanish ) , taggmakrill ( swedish ) , toro ( spanish ) , trnobokar ( serbian ) , uma - aji ( japanese ) , xareu ( portuguese ) , xareu - cavalao ( portuguese ) , xareu - macoa ( portuguese ) , and xareu - olho - de - boi ( portuguese ) .
size , age , and growth the maximum size of a crevalle jack is 39 . 8 inches ( 101 cm ) and 55 . 1 pounds ( 25 kg ) , however they are common to 23 . 6 inches ( 60 cm ) . after the juvenile reaches a size of 1 . 97 inches ( 5 . 0 cm ) , its growth rate increases . females are typically larger than males .
predators predators of the yellow jack include larger fishes , marine mammals , and birds including the brown noddy ( anous stolidus ) and sooty tern ( sterna fuscata ) which may feed on juveniles .
the yellow jack was originally described as caranx bartholomaei by the famous french taxonomist georges cuvier in 1833 . the holotype was collected from st . batholomew island in the west indies from which the species name is derived . this name was later changed to the currently valid carangoides bartholomaei cuvier 1833 . this species is in the family caragidae which includes jacks , pompanos , jack mackerels , and scads .
best angling for these strong fighters is from may to august with almost any bait or lure . once hooked , the common jack is tenacious with hard drives toward the bottom and frequent straightening of hooks .
crevalle jacks are pugnacious - looking fish which live up to those looks . a dark spot on the gill cover and steeply convex forehead separate this species from other jackfish . strong bony scutes on the tail are common to all jacks .
smith - vaniz wf , ke carpenter . 2007 . review of the crevalle jacks , caranx hippos complex ( teleostei : carangidae ) , with a description of a new species from west africa . fish bull 105 : 207 - 233 .
berry fh . 1959 . young jack crevalles ( caranx species ) off the southeastern atlantic coast of the united states . u . s . fish wildl . serv fish . bull . 152 : 417 - 535 .
for protection in open water , vulnerable young crevalle jacks use a behavior called
piloting
in which they stay within inches of a larger fish . if no large fish are around , they will shadow buoys , boats , or swimmers .
english language common names are yellow jack , coolihoo , crevalle , green jack , jackfish , and yellowjack . other common names include carangue gras ( french ) , carangue grasse ( french ) , carangue jaune ( french ) , bok ' abou ( papiamento ) , garajuba ( portuguese ) , xarelete - azul ( portuguese ) , xaréu ( portuguese ) , xerelete - amarelo ( portuguese ) , atún ( spanish ) , cibi amarillo ( spanish ) , coginoa ( spanish ) , cojinoa amarilla ( spanish ) , cojinoa tumana ( spanish ) , cojinua amarilla ( spanish ) , guaymen ( spanish ) , guaymen amarillo ( spanish ) , jurelete ( spanish ) , and veiyu ( wayuu ) .
game qualities : few fish can out - pull a crevalle of equal size . the fight is unspectacular but dogged , the usual pattern being a long first run . jacks use their flat sides to good advantage when waging a tug - o - war .
we removed the top loin of the jack . we removed the skin and every bit of bloodline . for those that don ' t know , the bloodline is a very dark area of most fish species , and is very strong .
the yellow jack has not been evaluated by the world conservation union ( iucn ) . the iucn is a global union of states , governmental agencies , and non - governmental organizations in a partnership that assesses the conservation status of species .
feeding habits determine many aspects of living organisms , where it lives , the time of day that it is active , energy flow , biomass consumed and intra - and interspecific interactions , it which provides information to make predictions about the effects of fisheries on predator - prey relationships . accurate predictions require a thorough understanding of predator diets and prey selection . in this study , specimens of the crevalle jack caranx caninus were obtained between october 2012 and october 2014 in the se gulf of california , mexico , in order to determine its feeding habits and prey selection . a total of 238 specimens were obtained , of which 94 ( 39 . 5 % ) had stomachs containing food and 144 ( 60 . 5 % ) had empty stomachs . a total of 10 prey items were identified , corresponding to seven families that included fishes , crustaceans and cephalopods . according to the index of relative importance ( iri ) the most important prey were anchoa spp . ( iri = 91 . 2 % ) , engraulis mordax ( iri = 1 . 8 % ) , and fish from the clupeidae family ( iri = 1 . 0 % ) . the crevalle jack’s diet did not change with the season ( warm or cold ) . the crevalle jack was considered a tertiary predator ( trophic level = 4 . 3 ) that tends to feed on a reduced number of prey , characterizing it as a specialist and selective predator of engraulid fishes ( levin’s index , bi = 0 . 08 ; e = 0 . 6 ) .
schools of crevalle jacks have been observed to corner and / or corral smaller baitfish . once contained , the jacks will feed on the baitfish with great voraciousness . their surface feeding commotion may be seen from a great distance - often appearing as boiling or churning surface waters .
you are of course saying sure , the last thing the cat dragged in would have tasted good if it was gussied up like that . that jack sure did , even by vollen’s standards , but that was not the half of the experiment .
yellow jack ( caranx bartholomaei ) other names : bar jack , cibi amarillo range : common in southern florida , the bahamas and the caribbean . habitat : inshore flats and channels ; coral reefs . description : more streamlined in appearance than the crevalle , and more colorful . hard scutes forward of tail . color is bluish above , yellowish on sides . small yellow jacks have fins and tails of bright yellow , giving them the appearance of yellowtail snapper when seen from above the surface . size : averages 1 - 6 pounds ; not uncommon at 12 - 15 pounds ; grows to about 20 pounds . world record 19 pounds , 7 ounces . food value : excellent . red meat along the centerline is easily trimmed away , leaving white , flavorful fillets . game qualities : like other jacks , a rugged and persevering fighter . tackle and baits : spinning , baitcasting and light saltwater outfits , will give good sport . small live fish , particularly ballyhoo and pilchards are the best natural baits . biggest bar jack have been caught on topwater plugs over channels and shallow reefs , and on deep jigs in up to about 120 feet of water . on the flats , the bigger bar jack are moody but smaller ones eagerly hit live shrimp . bonefish jigs and other small lures . fishing systems : casting ; drifting ; still fishing ; trolling .
considered a minor commercial species throughout its range , the yellow jack is taken by seines , trawls , and hook and line . recreational fishers also take this species with bait and lures while trolling without specifically targeting the yellow jack . the flesh is considered fair to good for human consumption and is marketed fresh and salted . however it is classified as a high risk species due to its implication in ciguatera poisoning in humans . in fact , it was the first species outside the indo - west pacific to be a confirmed ciguatera carrier .
berry , f . h . 1959a . young jack crevalles ( caranx species ) off the southeastern atlantic coast of the united states . fishery bull . fish wildl . serv . u . s . , ( 152 ) : pp . 417 - 535 , 98 fig .
behavior : crevalle jacks are usually found in fast - moving schools , though adults may be solitary or move in pairs . they hunt in schools by cornering smaller fish at the surface or against a seawall . they can tolerate different levels of salt water . they create splashes that can be seen from great distances .
so there you go—sautéed , chargrilled or fried crunchy , there doesn’t seem to be a way to mess up a jack , save one . back in my brief tenure as a snook guide , i had a repeat customer who was a light - tackle bluefish fanatic from long island .
smith - vaniz , w . f . and k . e . carpenter , 2007 . review of the crevalle jacks , caranx hippos complex ( teleostei : carangidae ) , with a description of a new species from west africa . fish . bull . 105 ( 2 ) : 207 - 233 . ( ref . 58464 )
the yellow jack is found in the western atlantic ocean from massachusetts to bermuda and south through the gulf of mexico and the caribbean including the west indies and on to são paulo , brazil . in the eastern central atlantic , this species has been documented at st . paul ' s rocks .
the crevalle jack has a body depth of about three times its fork length . it has large eyes . the chest is scaleless except for a small patch of scales in front of the pelvic fins . this patch is apparent by the time the fish reaches a fork length of 0 . 98 inches ( 2 . 5 cm ) . the crevalle jack is the only jack in the western atlantic ocean with this patch of scales . there is an oval black spot on the pectoral fins ; this appears at about 4 . 72 inches ( 12 . 0 cm ) . between the seventh and the eighth spines of the adult there is an overgrowth of skin . the two most distinguishable features of this fish are the patch of scales between the pelvic fins and the oval , black spot on the pectoral fins . the crevalle jack is greenish - bluish or bluish - black above and silvery white to yellowish or golden below . this serves to blend in with the water from a predator searching from above , and to blend with the sunlight from a predator hunting from below . there is an oval , black spot on the pectoral fins . juveniles have 5 dark bars on their bodies . these black bars are present until the fish reaches a size of 6 . 46 inches ( 16 . 4 cm ) . there is an area of dark pigment above the peduncle that appears at 1 . 18 in . ( 3 . 0 cm ) and is very dark once the fish reaches a size greater that 3 . 94 inches ( 10 . 0 cm ) in length . the juvenile has pigment spots on the anal spines and membranes , which disappear by the time its size reaches 1 . 38 inches ( 3 . 5 cm ) . the pelvic fin remains unpigmented after 0 . 79 inches ( 20 mm ) and at about 1 . 18 inches ( 3 . 0 cm ) the pigment of the caudal fins develops . the coloration of the juvenile holds between 0 . 79 - 1 . 57 inches ( 2 . 0 - 4 . 0 cm ) and fades between 1 . 57 - 1 . 97 inches ( 4 . 0 - 5 . 0 cm ) .
voracious predators , they feed on shrimp , other invertebrates , and smaller ﬁsh . crevalle jacks will often corner a school of baitﬁsh at the surface and feed in a commotion that can be seen for great distances , or they will chase their prey onto beaches and against seawalls . fish of both species often grunt or croak when they are caught .
start your favorite charcoal fire or gas grill . as the grill gets going , the preparation is easy : simply skewer the chunks of jack on the rosemary sticks . feel free to load them with onions or peppers for the full kabob experience , but for our preparation , we kept it all about the meat .
caranx ignobilis is most commonly referred to as the ‘giant trevally’ ( or ‘giant kingfish’ ) due to its large maximum size , with this often abbreviated to simply ‘gt’ by many anglers . [ 8 ] other names occasionally used include ‘lowly trevally’ , ‘barrier trevally’ , ‘yellowfin jack’ ( not to be confused with hemicaranx leucurus ) , forsskål’s indo - pacific jack fish and goyan fish . [ 4 ] in hawaii , the species is almost exclusively referred to as ‘ulua’ , often in conjunction with the prefixes ‘black’ , ‘white’ , or ‘giant’ . [ 9 ] due to its wide distribution there are many other names for the species in different languages also . [ 4 ]
so , if you are inclined to ignore the following revelations and rely on the advice of others , do yourself the favor of clarifying one simple point . ask anyone who disparages the flavor of crevalle if they ever have eaten it . likely they are just passing on a rumor started by some fish lover long ago , so he could have all the jacks for himself .
reproduction : crevalle jacks are known to spawn in both tropical and subtropical environments . females release eggs and males release sperm directly into the water . the sperm fertilizes any eggs it encounters ; this is known as broadcast spawning . fertilized eggs are planktonic , meaning that they float freely until hatching . young are often found in estuaries and move farther offshore to the open sea as they get older .
coloration the crevalle jack is greenish - bluish or bluish - black above and silvery white to yellowish or golden below . this serves to blend in with the water from a predator searching from above , and to blend with the sunlight from a predator hunting from below . there is an oval , black spot on the pectoral fins . juveniles have 5 dark bars on their bodies . these black bars are present until the fish reaches a size of 6 . 46 inches ( 16 . 4 cm ) . there is an area of dark pigment above the peduncle that appears at 1 . 18 in . ( 3 . 0 cm ) and is very dark once the fish reaches a size greater that 3 . 94 inches ( 10 . 0 cm ) in length .
so it was that i showed up at vollen’s back door with a half - dozen fillets of crevalle on ice . the sultry august day before , the 2 - to 3 - pound fish had been buzzing about in punta gorda isles canals . they were bled when caught , filleted and skinned within a couple of hours of being iced , but otherwise had not been given special treatment of any kind .
blue runner ( caranx crysos ) other names : hardtail jack , runner , blue jack range : all florida , the bahamas and the caribbean . habitat : not choosy ; inshore to deep sea . description : similar in shape to the crevalle , but with a more gently rounded head . color ranges from steel blue to light green with white underparts . hard scutes forward of tail . size : schooling blue runners are about the same size , averaging under a pound and often under a half - pound . fish weighing 1 - 2 pounds aren ' t unusual , and individuals up to 4 pounds or so are sometimes taken offshore . world record 11 pounds , 2 ounces ; florida record 7 pounds . food value : pretty good , but seldom eaten . game qualities : blue runners fight so well for their size that guides often have trouble tearing their customers away , after stopping to catch some runners on spinning tackle for use as offshore bait . tackle and baits : light spinning and fly tackle with live shrimp , cut pieces of fish or small artificial jigs and flies . fishing systems : casting ; drifting ; still fishing ; trolling .
rainbow runner ( elagatis bipinnulata ) other names : spanish jack , rainbow jack range : not a staple species off florida , but often encountered by offshore anglers of both coasts , particularly dolphin fishermen . more common in bahama waters , particularly around the cay sal bank ; also widespread through the caribbean . habitat : deep ocean waters . description : un - jack streamlined shape with slender , pointed head . no hard scutes forward of tail . brilliantly colored , with blue and yellow full - length stripes on a blue background . size : varies from a couple of pounds to 15 or 20 pounds , with individuals of roughly the same size forming large schools . world record 37 pounds , 9 ounces ; florida record 17 pounds . food value : excellent . game qualities : a spirited fighter on light tackle . makes faster runs than other jacks , and sometimes jumps , too . tackle and baits : spinning , baitcasting and light ocean rigs . small live fish and small rigged baits , such as ballyhoo and strips . difficult to take by casting , but can be coaxed . fishing systems : casting ; trolling .
there have been some reports of ciguatera poisoning associated with this jack . ciguatera poisoning occurs when humans eat a fish that has eaten a toxin that is produced by the dinoflagellate , gambierdiscus toxicus , and it is digested by the fish . this poisoning , although it is usually self - limiting , can affect humans in many ways . it has gastrointestinal , neurological , and cardiovascular symptoms .
for my test of crevalle i enlisted the help of fort myers chef vollen loucks . vollen loucks is not an army - trained 94 - b - 20 - type cook , as i was , but a guy whose pinot noir sauce could transform tongue of combat boot into haute cuisine . besides which , vollen will be the first to tell you he is not a real seafood lover , although that did not stop salmon from being his restaurant’s biggest seller .
manter & prince ( 1953 ) described l . fijiensis from two specimens from “yellow jack” [ 15 ] ; the identification of the host fish is vague , as often with manter ' s work ( other cases : [ 46 ] , [ 47 ] ) , and almost useless ( many carangids are partly yellow ) . only one monogenean specimen , the holotype of l . fijiensis , is kept in the usnpc collections ( figure 1 ) .
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residing on offshore reefs and in the sandy shallows of caribbean islands as well as in open waters over the continental shelf , this jack is rare observed in shallow waters near the american continent . it lives at depths ranging from 0 - 164 feet ( 0 - 50 m ) . juveniles of this species are often found nearshore in seagrass beds or associated with jellyfish or floating sargassum weed . typically it is a solitary species but may at times been seen in small groups .
habitat : the crevalle may show up at any time in virtually all florida waters , from the deep reefs to well up coastal rivers . usually runs in schools—and the smaller the individual fish , the larger the school . the biggest jacks often cruise in pairs and are usually found in or near major inlets and around offshore wrecks and reefs of both coasts , but may come into deep bays and canals where they chase mullet and often herd the prey against seawalls . the palm beaches and key west are particularly well - known areas for trophy crevalles .
oh sure , you say , you’ve long heard of eating amberjack . but we’re not talking ajs , or any of their first cousins , or any fancy jacks like rainbow runners or bar or even yellow jacks . we’re talking plain old everyday crevalle jacks , and we recommend you don’t skip to the next story unless you already know how good jacks are to eat . after all , were a quarter - million bahamians wrong about conch fritters ? throughout the bahamas and the caribbean , jacks of all kinds are esteemed for their rich flavor and firm flesh .
with the crunchy jacks he provided two dressings—a homemade rémoulade and a mango mayonnaise—either of which was to die for if your arteries were not up to the task . fortunately , i was too stuffed to do more than taste the combinations , both of which were splendid , as by that time we expected . what was unexpected was how unbelievably good the remaining seven pieces of fried jack were after i doggy - bagged them and ate them cold , one by one , straight out of my refrigerator over the following two days .
various fish specimens were identified ( from photographs ) by ronald fricke , jack randall , michel kulbicki , samuel iglésias and bernard séret . eric bureau , student in training , collected some specimens . david gibson ( bmnh ) helped with linguistic discussions , and in the acquisition of rare literature and comments about species in worms . patricia pilitt ( usnpc ) provided photomicrographs of the holotype of l . fijiensis , and takashi iwaki ( mpm ) kindly took photographs of additional museum specimens . patricia pilitt ( usnpc ) and eileen harris ( bmnh ) are thanked for arranging specimen loans .
a large fish , the yellow jack grows to a maximum reported length of just under 40 inches ( 100 cm ) total length ( tl ) although this species typically reaches 20 inches ( 50 . 0 cm ) tl . the maximum reported weight is 14 . 0 kg . yellow jacks reach sexual maturity at 12 inches ( 30 cm ) in length for males and 13 inches ( 32 cm ) in length for females in the waters off cuba . in contrast , off the coast of jamaica , males reach sexual maturity at 9 inches ( 23 cm ) in length .
the next fillet was simply tossed on a 90 , 000 - b . t . u . grill that etched dark brown crisscrosses into each side , while leaving clear juice in the center . there was no stopping vollen and his sauces , one of which was purée of prickly pears he had plucked from a cactus patch outside his back door . the artfully drizzled sauce was as vibrant to taste as it was brilliant to behold , but it served as it should have—a mere complement to the delicious flavor of the grilled jack , which we agreed was even better than that sautéed .
the horse - eye jack is commonly found in the subtropical atlantic ocean from bermuda and the northern gulf of mexico and south to rio de janeiro . in the eastern atlantic , it is found from st . paul ' s rocks to ascension island and , rarely , the in the gulf of guinea . it is a pelagic fish . it can be found on reefs and offshore oil rigs . the juvenile can be found closer to shore along sandy and muddy bottoms . the species may venture into brackish waters and can live in river mouths , but it is typically found in saltwater up to 140 m in depth .
our species is the first referred to lethacotyle with a precise host identification . we have examined a number of other carangids from several genera off new caledonia [ 47 ] , [ 49 ] – [ 53 ] and found l . vera n . sp . only on c . papuensis , suggesting that species of lethacotyle are specific to caranx species . it is likely that the “yellow jack” of manter & prince ( 1953 ) [ 15 ] and the carangid of ramalingam [ 17 ] , [ 18 ] , both identified with suboptimal precision , were species of caranx , but , as explained above , not necessarily conspecific .
scientific synonyms and common names caranx hippos linnaeus , 1766 synonyms : scomber hippos linnaeus , 1766 , syst . nat . , ed . xii : 494 ( ' habitat in carolina ' ) . scomber carangus bloch , 1787 , naturg . ausl . fische , 7 : 69 , pl . 340 ( west indies ) . caranx erythrurus lacepède , 1798 - 1803 , 1801 , hist . nat . poiss . , 3 : 58 & 68 ( ' caroline et tahiti ' ) . caranx carangus : cuvier , in cuv . val . , 1828 - 1849 , 1833 , 9 : 91 ( ' brésil , cayenne , martinique , gorée ' ) barnard , 1926 - 1927 , 1927 : 545 . caranx crysos ( nec mitchill ) : baird , 1855 : 336 gill , 1863 : 434 . carangus hippos : gill , 1863g : 433 . caranx caninus günther , 1869 , trans . zool . soc . lond . , 6 ( 7 ) : 432 . caranx hippos hippos : nichols , 1920b : 45 ( atlantic coast of united states ) . caranx hippos tropicus : nichols , 1920b : 45 ( brazil , congo ) . caranx hippos caninus : nichols , 1937a : 58 ( gulf of california , galapagos ) . caranx hippos : nichols , 1939 : 6 lozano rey , 1952 : 615 , fig . 27 tortonese , 1952b : 302 , fig . 11 - 13 poll , 1954 : 131 , fig . 37 , pl . 4 ( fig . 11 & 3 ) albuquerque , 1954 - 1956 : 673 tortonese , 1955a : 185 berry , 1959a : 503 , fig . 81 - 85 tortonese , 1961a : 357 bini , 1967 - 1972 , 1968 , 5 : 57 , col . fig . rodriguez , 1972 : passim . common names : alla [ es ] caballa [ es ] crevalle jack [ en ] grande carangue [ fr ] jurel commun [ es ] kingfish [ en ] yellow jack [ en ]
pilotfish ( naucrates ductor ) range : all florida , the bahamas and caribbean . habitat : offshore waters . name comes from accompanying sharks and other large animals seemingly as pilots . description : slender shape with tapering head . body marked by wide , dark bands . fins also banded . size : usually a foot or so ; grows to 2 feet . food value : good , if fish is large enough . game qualities : good on light tackle ; gives the fight of a typical small jack . tackle and baits : readily takes small jigs and streamer flies . only very light outfits provide much sport . fishing systems : offshore drifting .
the yellow jack has a moderately deep , compressed elongate body which is typical of the genus carangoides . the head is slightly curved from the snout to the nape ; the eyes have well - developed adipose eyelids . the upper jaw does not reach the anterior margin of the eye . the dorsal fin is divided into two parts with the first containing 7 spines and the second with 1 spine followed by 25 - 28 soft rays . the anal fin is similar to the second dorsal fin in that the lobes are slightly pronounced ; the pectoral fin is falcate and longer than the head . the caudal fin is forked and the caudal peduncle has bilateral paired keels present .
seriola rivoliana is mostly pelagic and epibenthic in oceanic waters ; it is rarely found inshore . it feeds primarily on fishes . in the azores , this species feeds on fishes including chub mackerel scomber japonicus , blue jack mackerel , european pilchard sardina pilchardus , snipefish macroramphosus scolopax , and the bogue boops boops ( barreiros et al . 2003 ) . this species typically reaches a maximum size to 80 cm ( fl ) , it is common from about 55 cm ( fl ) ( smith - vaniz 2002 ) . there is an international game fish association ( igfa ) record of 119 cm ( tl ) from golfito , costa rica ( igfa 2013 ) . this species has been reported to form spawning aggregations in gladden spit , belize ( heyman 2001 ) .
florida pompano ( trachinotus carolinus ) other names : pompano , carolina pompano range : all florida coasts . habitat : florida anglers on both coasts catch most of their pompano from the surf , or from ocean piers ; however , many are caught outside the beaches and also from bays , mostly in or near channels that run through flats . description : silvery overall with yellow on underside . dorsal fin dark ; other fins yellow . head gently rounded . no scutes forward of tail . pompano are often confused with small permit of similar size , but permit usually show a black blotch under the pectoral fin , and their bodies are deeper . size : averages 1 pound ; fairly common at 2 pounds and can grow to 8 pounds . world and florida records 8 pounds , 1 ounce . food value : reputed to be the best . game qualities : tops . will outrace and outpull a jack crevalle of equivalent size . tackle and baits : if fishing the surf or piers , use the lightest surf spinning tackle that will get your bait where you want it . in other situations , spinning or light baitcasting tackle with 6 - 8 pound - test line gives maximum sport . by far the best natural bait is a live sand flea ( sand crab ) , but pompano also will bite live shrimp or fiddler crabs and with varying dependability dead sand fleas , dead shrimp , clams and cut squid . pompano are ready strikers of artificial jigs , the florida favorite being quarter - ounce or half - ounce models with short nylon skirts . fly fishermen catch pompano with bonefish - type flies that sink well those with epoxy heads or lead eyes . fishing systems : casting ; drifting ; still fishing .


crotalus lepidus is a venomous pit viper species found in the southwestern united states and northern central mexico .

four subspecies are currently recognized , including the nominate subspecies described here .

crotalus lepidus

comparison of venom composition and biological activities of the subspecies crotalus lepidus lepidus , crotalus lepidus klauberi and crotalus lepidus morulus from mexico .
crotalus lepidus lepidus ( kennicott 1861 ) caudisona lepida kennicott 1861 : 206 crotalus lepidus lepidus — gloyd 1936 crotalus lepidus — cope 1883 crotalus semicornutus taylor 1944 crotalus lepidus lepidus — klauber 1952 : 45 crotalus lepidus castaneu crotalus lepidus — stebbins 1985 : 227 crotalus lepidus lepidus — conant & collins 1991 : 237 crotalus lepidus lepidus — liner 1994 crotalus lepidus — mcdiarmid , campbell & touré 1999 : 287 crotalus lepidus lepidus — tennant & bartlett 2000 : 535 uropsophus lepidus — hoser 2009 crotalus lepidus — wallach et al . 2014 : 191 crotalus lepidus klauberi gloyd 1936 crotalus lepidus klauberi gloyd 1936 crotalus lepidus klauberi — klauber 1952 : 53 crotalus lepidus kaluberi [ sic ] — van devender & lowe 1977 crotalus lepidus klauberi — stebbins 1985 : 228 crotalus lepidus klauberi — tanner 1985 : 663 crotalus lepidus klauberi — conant & collins 1991 : 237 crotalus lepidus klauberi — liner 1994 crotalus lepidus klauberi — dixon 2000 crotalus lepidus klauberi — tennant & bartlett 2000 : 538 crotalus lepidus klauberi — bryson 2007 crotalus lepidus klauberi — love 2011 crotalus lepidus klauberi — monzel 2012 crotalus lepidus klauberi — werning 2012 crotalus lepidus klauberi — weima 2013 crotalus lepidus maculosus tanner , dixon & harris 1972 crotalus lepidus maculosus tanner , dixon & harris 1972 crotalus lepidus maculosus — liner 1994 crotalus lepidus maculossus — welch 1994 : 47 ( in error ) crotalus lepidus maculosus — beaman & hayes 2008
comparison of venom composition and biological activities of the subspecies crotalus lepidus lepidus , crotalus lepidus klauberi and crotalus lepidu . . . - pubmed - ncbi
crotalus lepidus morulus klauber 1952 : 52 crotalus lepidus morulus — liner 1994 crotalus lepidus morulus — bryson 2007 crotalus morulus — bryson et al . 2014 crotalus morulus — terán - juárez et al 2016
these are relatively small rattlesnakes . crotalus oreganus was included in crotalus viridis until recently ( see crotalus viridis account ) .
comparison of venom composition and biological activities of the subspecies crotalus lepidus lepidus , c . l . klauberi and c . l . morulus from mexico .
venom phenotypes of the rock rattlesnake ( crotalus lepidus ) and the ridge - nosed rattlesnake ( crotalus willardi ) from méxico and the united states .
beaupre , s . 1993 . an ecological study of oxygen - consumption in the mottled rock rattlesnake , crotalus - lepidus - lepidus , and the black - tailed rattlesnake , crotalus - molossus - molossus .
venom phenotypes of the rock rattlesnake ( crotalus lepidus ) and the ridge - nosed rattlesnake ( crotalus willardi ) from méxico and the united states . - pubmed - ncbi
liner , e . a . , and a . h . chaney . 1986 . crotalus lepidus lepidus ( mottled rock rattlesnake ) . reproduction . herpetological review 17 ( 4 ) : 89 .
a characteristic distinguishing it quite well ( apart from the livery ) from the crotalus lepidus lepidus is the absence of the typical dark line going , in this last one , from the buccal rima to the eye .
we characterized the venom of three subspecies of c . lepidus complex from mexico .
strimple , pete 1993 . report on the feeding and growth of a juvenile mottled rock rattlesnake , crotalus lepidus lepidus , during three years in captivity . litteratura serpentium 13 ( 3 ) : 89 - 94 - get paper here
velde , hans v . d . 1995 . breeding results : crotalus lepidus klauberi . litteratura serpentium 15 ( 5 ) : 134 - get paper here
goldberg , stephen r . 2000 . reproduction in the rock rattlesnake , crotalus lepidus ( serpentes : viperidae ) . herpetological natural history 7 ( 1 ) : 83 - 86
on these background colours stand out some well spaced bands , of dark colour , black or brown , and , among them , are often spread small dark spots which , however , are never so thick and close as is the case of the subspecies crotalus lepidus lepidus .
goldberg , s . 1999 . reproduction in the blacktail rattlesnake , crotalus molossus .
portrait of a southern pacific rattlesnake ( crotalus viridis helleri ) on white background .
the greatest recorded length for a c . l . lepidus specimen is 775 mm ( boundy , 1995 )
mata - silva , vicente , jerry d . johnson and arturo rocha . 2011 . crotalus lepidus ( rock rattlesnake ) feeding behavior . herpetological review 42 ( 3 ) : 439 - get paper here
desantis , dominic l . , vicente mata - silva and jerry d . johnson . 2015 . crotalus lepidus ( rock rattlesnake ) diet / scavenging . herpetological review 46 ( 2 ) : 268 - 269
gloyd , howard k . 1936 . the subspecies of crotalus lepidus . occasional papers of the museum of zoology , university of michigan ( 337 ) : 1 - 5 + 1 plate - get paper here
mata silva , vicente ,
ecology of the rock rattlesnake , crotalus lepidus , in the northern chihuahuan desert
( 2011 ) . etd collection for university of texas , el paso . aai3489984 . urltoken
beaupre , s . j . 1995 . comparative ecology of the mottled rock rattlesnake , crotalus lepidus , in big ben national park . herpetologica 51 ( 1 ) : 45 - 56 . [ links ]
banda - leal , javier , david lazcano , manuel nevárez - de los reyes and alejandro huereca - delgado . 2015 . crotalus lepidus ( rock rattlesnake ) diet . herpetological review 46 ( 1 ) : 102
1 , 434 crotalus stock photos , vectors , and illustrations are available royalty - free .
beaupre , s . j . 1996 . field metabolic rate , water flux , and energy budgets of mottled rock rattlesnakes , crotalus lepidus , from two populations . copeia 1996 ( 2 ) : 319 - 329 .
51 - swinford , g . w . 1994 . project summary 1991 - 1994 , a continued study of the mottled race of the rock rattlesnake , crotalus lepidus lepidus , in southeastern new mexico currently listed state endangered . share with wildlife , new mexico department of game and fish . contract # 93 - 516 . 6 - 2 . view document
western diamondback bites camera ! ! ! red crotalus atrox a . k . a . blood diamond
tanner , wilmer w . , james r . dixon and herbert s . harris 1972 . a new subspecies of crotalus lepidus from western mexico . great basin naturalist 32 ( 1 ) : 16 - 24 - get paper here
for information on c . lepidus klauberi , which is also found in new mexico , texas , and arizona , see 030174 .
jacob , j . s . , and j . s . altenbach . 1977 . sexual dimorphism in crotalus lepidus klauberi gloyd ( reptilia , serpentes , viperidae ) . journal of herpetology 11 ( 1 ) : 81 - 84 .
johnson , t . b . , and g . s . mills . 1982 . a preliminary report on the status of crotalus lepidus , c . pricei , and c . willardi in southeastern arizona . arizona natural heritage program , phoenix .
mccrystal , h . k . , c . r . schwalbe , and d . f . retes . 1996 . selected aspects of the ecology of the arizona ridge - nosed rattlesnake ( crotalus willardi willardi ) and the banded rock rattlesnake ( crotalus lepidus klauberi ) in arizona . report to the arizona game and fish department , heritage grant iipam 192034 .
the rock rattlesnakes , labelled with the scientific name of crotalus lepidus - kennicott , 1861 , are small viperids ( viperidae ) , afferent to the well known subfamily of the crotalides ( crotalinae ) having an elegant look , as suggested by the latin scientific name , “lepidus” , which , besides being a proper name of the old rome , means something like “graceful” , “elegant” , or “coy” .
carbajal - marquez , rubén alonso and gustavo e . quintero - diaz . 2015 . diet of crotalus lepidus ( serpentes : viperidae ) in mesa montoro , aguascalientes , méxico . revista mexicana de herpetología 1 ( 1 ) : 18–21 - get paper here
( crotalus viridis viridis , ) . paper presented at meeting of the animal behavior society , tucson , az .
christman , b . l . , a . barkalow , r . d . jennings , g . l . hamilton and j . bain 2016 . crotalus lepidus kaluberi ( banded rock rattlesnake ) diet / mortality . herpetological review 47 ( 3 ) : 477 .
the treatments represent the phenotypic extremes of crotalus l . lepidus found in eastern and western regions of west texas ( refer to figure 1a ) . the treatments are ( from left to right ) eastern unblotched , eastern blotched , western unblotched , and western blotched .
natureserve explorer , 2004 .
crotalus molossus
( on - line ) . accessed july 06 , 2004 at urltoken .
great basin rattlesnakes ( crotalus viridis lutosis ) are the only venomous reptiles in most of the great basin desert . night scene
rattlesnake of the reeds . rattlesnakes are a group of venomous snakes of the genera crotalus and sistrurus of the subfamily crotalinae .
tanner , wilmer w . ; dixon , james r . ; and harris , herbert s . jr . ( 1972 )
a new subspecies of crotalus lepidus from western mexico ,
great basin naturalist : vol . 32 : no . 1 , article 2 . available at : urltoken
the northwestern neotropical rattlesnake is characterised by its large size , pronounced vertebral ridge , and a highly potentent venom . crotalus culminatus .
an examination of additional specimens of crotalus lepidus from western durango and the adjacent parts of sinaloa and nayarit have demonstrated the validity of klauber ' s ( 1956 ) suggestion that a new subspecies may occur . the new subspecies ( c . l . maculosus ) is described and compared to other subspecies .
mata - silva , vicente , jerry d . johnson , arturo rocha , and steven dilks 2014 . rainwater - harvesting by the rock rattlesnake , crotalus lepidus , in the chihuahuan desert of western texas . southwestern naturalist jun 2014 , vol . 59 , no . 2 : 303 - 304 . - get paper here
panamint rattlesnake ( crotalus mitchellii stephensi ) under a pinyon pine tree in basin and range national monument , lincoln county , nevada , usa .
geographical distribution of crotalus durissus with stomach contents from central region of brazil covering forest formations of amazon and atlantic forest , caatinga and cerrado .
food composition in individual males , females , newborns and juveniles of crotalus durissus from central region of brazil ( n = 30 snakes ) .
winchell , s . 2007 . klapperschlangen ! die gattung crotalus . reptilia ( münster ) 12 ( 66 ) : 18 - 25 - get paper here
molecular model of snake venom toxin convulxin found in a tropical rattlesnake crotalus durissus terrificus , 3d illustration . this toxin causes blood clot formation after snake bite
echeverrigaray , s . , grazziotin , g . , grazziotin , f . & agostini , g . 2000 . random amplified polymorphisms between two south american subspecies of rattlesnakes ( crotalus durissus collilineatus e crotalus durissus terrificus ) . braz . arch . biol . techn . 313 - 317 . [ links ]
holycross , a . t . , c . w . painter , d . b . prival , d . e . swann , m . t . schroff , t . edwards , and c . r . schwalbe . diet of crotalus lepidus klauberi ( banded rock rattlesnake ) . journal of herpetology 36 ( 4 ) : 589 - 597 .
lepidus : usa ( se new mexico , sw texas ) , ne mexico ( chihuahua [ hr 31 : 113 ] , coahuila ) ; type locality : presidio del norte and eagle pass , texas .
a further odd and interesting characteristic is the longevity of these small viperids : often bigger animals do have a longer life than the small ones , but it is not always the case , and the crotalus lepidus may live up to 25 and more years , third in ranking , among the crotalides , after crotalus atrox and agkistrodon contortrix ( 30 and 29 years respectively ) … . maybe thanks to its retired and monastic life , as a hermit of the mountains , little prone to the stress and lover of its own privacy .
models were placed in the eastern region on limestone rocks and western region on volcanic rocks ( refer to figure 1a ) during the course of the predation study . the upper graph ( a ) is showing the proportion of attacks on models that mimicked the coloration of crotalus l . lepidus from the eastern region . the lower graph ( b ) is showing the proportion of attacks on models that mimicked the coloration of c . l . lepidus from the western region . the x - axis indicates the type of damage the models sustained as either avian attacks or non - predator disturbances .
the western diamondback rattlesnake or texas diamond - back ( crotalus atrox ) is a venomous rattlesnake species found in southwestern united states , mexico . likely responsible for snakebite fatalities
food item , ameiva ameiva , recorded in the stomach of a female crotalus durissus . specimen deposited in the coleção herpetológica da universidade de brasília ( chunb 49673 ) .
to cite this page : desai , m . 2004 .
crotalus molossus
( on - line ) , animal diversity web . accessed july 09 , 2018 at urltoken
clark , r . w . 2002 . diet of the timber rattlesnake crotalus horridus . j . herpetol . 36 ( 3 ) : 494 - 499 . [ links ]
prival , d . b . , and j . p . porter . 2016 . rock rattlesnake crotalus lepidus ( kennicott 1861 ) . pages 433 - 459 in g . w . schuett , m . j . feldner , c . f . smith , and r . s . reiserer ( eds ) . 2016 . rattlesnakes of arizona , volume 1 . eco herpetological publishing , rodeo , nm .
prival , d . b . 2008 . morphology , reproduction , and habitat use of a northern population of banded rock rattlesnakes , crotalus lepidus klauberi . pages 431 - 440 in w . k . hayes , k . r . beaman , m . d . cardwell , and s . p . bush ( editors ) , the biology of rattlesnakes . loma linda university press , loma linda , california .
i was interested to here your description of color variants to c . l . klauberi . i have seen specimens at the arizona sonora desert museum and also have been on trips to the chiricahuas and huachucas where we collected them on talus slopes . all of these specimens were green . at the museum and in the snakes of arizona by fowlie , crotalus lepidus klauberi is referred to as the green rock rattlesnake .
such small litters mean that although c . l . lepidus breeds every year , it still has a low reproductive rate . most young are born in mid - to late summer , 8 to 10 after mating ( tennant , 1984 )
holycross , a . t . , painter , c . w . , prival , d . v . , shawnn , d . e . , schroff , m . j . , edwards , t . & schwalbe , c . r . 2002 . diet of crotalus lepidus klauberi ( banded rock rattlesnake ) . j . herpetol . 36 ( 4 ) : 589 - 597 . urltoken ; 2 [ links ]
crotalus molossus is a venomous pit viper species found in the southwestern united states and mexico . common names : black - tailed rattlesnake , green rattler , northern black - tailed rattlesnake .
borja , miguel ; david lazcano , gerardo martínez - romero , jesús morlett , elda sánchez , ana c . cepeda - nieto , yolanda garza - garcía , and alejandro zugasti - cruz 2013 . intra - specific variation in the protein composition and proteolytic activity of venom of crotalus lepidus morulus from the northeast of mexico . copeia dec 2013 , vol . 2013 , no . 4 : 707 - 716 . - get paper here
big curve creepy viperidae crotalus asp serpentine on white backdrop . outline black ink hand drawn zoo pictogram emblem logo sketchy in art retro doodle style pen on paper space for text . closeup view
hoser , r . 2009 . a reclassification of the rattlesnakes ; species formerly exclusively referred to the genera crotalus and sistrurus . australasian j . herpetol . 3 : 1 - 21 - get paper here
late pleistocene and holocene snakes from the great basin and the colorado plateau include the genus , crotalus , and the species , c . viridis ( mead and bell , 1994 ) * 34 * .
macarthney , j . m . 1989 . diet of the northern pacific rattlesnake , crotalus viridis oreganus , in british columbia . herpetologica 45 ( 3 ) : 299 - 304 . urltoken [ links ]
santos , s . m . & germano , v . j . 1996 . crotalus durissus ( neotropical rattlesnake ) prey . herpetol . rev . 27 ( 3 ) : 143 . [ links ]
considering data to other viperids ( sawaya et al . 2008 ; marques et al . 2009 ; barbo et al . 2011 ) the frequency of individuals of crotalus durissus with prey in the stomach was low .
the specific name apparently comes from the latin word lapidis , meaning
stone ,
in reference to the snakes ' affinity for living in rocky terrain , or perhaps from the latin adjective lepidus , meaning
pleasant or charming
( lemos - espinal & dixon 2013 ) .
pifano , f . & rodriguez - acosta , a . 1996 . ecological niche and redescription of crotalus vegrandis ( serpentes : crotalidae ) in venezuela . brenesia 45 - 46 : 169 - 175 . [ links ]
ty - jour ti - a new subspecies of crotalus lepidus from western mexico t2 - the great basin naturalist . vl - 32 ur - urltoken pb - m . l . bean life science museum , brigham young university , cy - provo , utah : py - 1972 sp - 16 ep - 24 do - 10 . 5962 / bhl . part . 25765 sn - 0017 - 3614 au - tanner , w w au - dixon , j r au - harris , h s er -
hoyos , m . a . 2012 . a cascavel neotropical crotalus durissus : uma abordagem morfológica e da história natural em populações do brasil . tese de doutorado , universidade de são paulo , são paulo . [ links ]
wüster , w . & bérnils , r . s . 2011 . on the generic classification of the rattlesnakes , with special reference to the neotropical crotalus durissus complex ( squamata : viperidae ) . zoologia 28 ( 4 ) : 417–419
the head of the lepidus is triangular and distinct from the neck , also if less evidently than what happens in other crotalides , the eye has elliptic and vertical pupil , and , in fact , this serpent is of mainly crepuscular and nocturnal habits , even if it may be met during the day .
tozetti , a . m . , & martins , m . 2008 . habitat use by the south - american rattlesnake ( crotalus durissus ) in southeastern brazil . journal of natural history 42 : 1435 - 1444 . urltoken [ links ]
collection sites with voucher numbers of studied specimens of crotalus durissus and stomach contents from central region of brazil . chunb , coleção herpetológica da universidade de brasília ; ibsp , instituto butantan ; mzusp , museu de zoologia da universidade de são paulo .
diller , l . v . & wallace , r . l . 1996 . comparative ecology of two snake species ( crotalus viridis and pituophis melanoleucus ) in southwestern idaho . herpetologica 52 ( 3 ) : 343 - 360 . urltoken [ links ]
sant ' anna , s . & abe a . s . 2007 . diet of the rattlesnake crotalus durissus in southeastern brazil ( serpentes , viperidae ) . stud . neotrop . fauna e . 42 ( 3 ) : 169 - 174 . urltoken [ links ]
beaupre , s . j . , duvall , d . & o ' leile , j . 1998 . ontogenetic variation in growth and sexual size dimorphism in a central arizona population of the western diamondback rattlesnake ( crotalus atrox ) . copeia 1 : 40 - 47 . [ links ]
bryson jr , robert w . ; robert w . murphy , amy lathrop and david lazcano - villareal 2011 . evolutionary drivers of phylogeographical diversity in the highlands of mexico : a case study of the crotalus triseriatus species group of montane rattlesnakes . journal of biogeography 38 : 697–710 - get paper here
salomão , m . g . , almeida - santos , s . m . & puorto , g . 1995 . activity pattern of crotalus durissus ( viperidae , crotalinae ) : feeding , reproduction and snakebite . stud . neotrop . fauna e . 30 ( 2 ) : 101 - 106 [ links ]
prairie rattlesnakes ( crotalus viridis ) exhibited a sustained high rate of tongue flicking after a predatory strike whether or not rodent odors were present in the poststrike environment . for the lizard specialist , c . pricei , strike - induced chemosensory searching was maintained at a high level only when chemical cues were available following the strike .
campbell , j . a . , e . d . brodie , jr . , d . g . barker , and a . h . price . 1989 . an apparent natural hybrid rattlesnake and crotalus willardi ( viperidae ) from the peloncillo mountains of southwestern new mexico . herpetologica 45 ( 3 ) : 344 - 349 .
northern populations of black - tailed rattlesnakes recently have been recognized as actually consisting of two species , crotalus molossus and c . ornatus ( anderson and greenbaum 2012 ) . populations west of southwestern new mexico are recognized as c . molossus , but relatively little change in the boundary would put c . ornatus into the california wash area .
the herpetologist james bear , tragically passed away in 2008 due to the bite of a crotalus horridus , reported the following variants : in the chiricahua zone , a marbled or mottled livery with silver and black shades , a black predominance on the franklin mountains , whilst other specimens show light blue , or lavender , or pink or green colours .
the south - american rattlesnake crotalus durissus , is restricted to south america ( campbell & lamar 2004 ) and has a discontinuous distribution ( wüster et al . 2005 ) from colombia to argentina ( vanzolini et al . 1980 ) . some populations exhibit considerable ecological variation , with closeby populations differing greatly from each other ( campbell & lamar , 2004 ) .
a free - ranging specimen of crotalus durissus unicolor on aruba island was observed after striking rodent prey ( calomys hummelincki ) and after no - strike presentations . strike - induced chemosensory searching and trail following were seen after strikes . when a chemical trail was not present following a strike , the snake searched extensively near its refuge , but never emerged from it .
prival , d . b . , goode , m . j . , swann , d . e . , schwalbe , c . r . & schroff , m . j . 2002 . natural history of a northern population of twin - spotted rattlesnakes , crotalus pricei . j . herpetol . 36 ( 4 ) : 598 - 607 . urltoken ; 2 [ links ]
the venom , besides the cytotoxins , which cause skin and muscular necrosis , has an haemotoxic action , with possible seemingly paradoxical and opposite phenomena of haemorrhages and thrombosis , but it has also neurotoxins which , even if not so much strong as in other species of rattlesnakes ( crotalus durissus o cascavel ) and of many elapids , may worsen the symptoms and cause breathing and cardiac problems .
wüster , w . , ferguson , j . e . , quijada - mascareñas , j . a . , pook , c . e . & salomão , m . d . 2005 . tracing an invasion : landbridges , refugia , and the phylogeography of the neotropical rattlesnake ( serpentes : viperidae : crotalus durissus ) . mol . ecol . 14 ( 4 ) : 1095 - 1108 . urltoken [ links ]
bryson , robert w . ; jr . , charles w . linkem , michael e . dorcas , amy lathrop , jason m . jones , javier alvarado - díaz , christoph i . grünwald & robert w . murphy 2014 . multilocus species delimitation in the crotalus triseriatus species group ( serpentes : viperidae : crotalinae ) , with the description of two new species . zootaxa 3826 ( 3 ) : 475–496 - get paper here
quijada - mascareñas , j . a . , ferguson , j . e . , pook , c . e . , salomão , m . g . , thorpe , r . s . & wüster , w . 2007 . phylogeographic patterns of trans - amazonian vicariants and amazonian biogeography : the neotropical rattlesnake ( crotalus durissus complex ) as an example . j . biogeogr . 34 : 1296 - 1312 . urltoken [ links ]
each of 10 prairie rattlesnakes ( crotalus viridis ) was exposed to three types of trails after striking rodent prey ( mus musculus ) . one trail was made with mouse urine , another was made with tap water , and the third consisted of materials from mouse integument . the snakes exhibited trailing behavior only when integumentary trails were available . it was concluded that prairie rattlesnakes do not utilize urinary cues ; instead they attend to materials associated with rodent skin and fur .
the copperhead and cottonmouth occur only east of our region . however , the region hosts a large number of species of rattlesnake , all of which are placed in the genus crotalus except for the massasauga ( sistrurus catenatus ) . although crotalid vertebrae are distinctive from those of other snakes of our region , few if any species are identifiable with certainty on the basis of vertebrae . although there are differences in adult size among the species , this seldom is conclusive in identification .
all food items were removed from the stomach and identified to the lowest possible taxonomic level . each of the contents was deposited in a glass container with the same identification number as the specimen ( voucher number ) . the intestinal content was determined while taking into account the type of food residue . in addition , available literature records of prey were included in this study , which analyzed the food composition for crotalus durissus from southeastern brazil ( santos & germano 1996 ; sant ' anna & abe 2007 ) .
2013 : rattlesnakes , primarily of the genus crotalus , are harvested in rattlesnake round - ups for the meat and skin trade * 54 * . 2013 : although the effect of snake harvest on some local populations should be taken seriously , the numbers are not nearly as staggering as the number of snakes lost to road mortality * 54 * . 2016 : as the climate changes this species’ range is predicted to decrease by 4 % by 2039 and 8 % by 2099 from its current range * 53 * .
mammal specialization may be related to several life history strategies ( martins et al . 2002 ) . in some species of pitvipers , it could be associated with the increased venom toxicity in juveniles ; this may be a consequence of the need to immobilize larger prey such as a mammal ( andrade & abe 1999 ) . furthermore , the adoption of a juvenile diet based on mammals is more profitable energetically than an ecthothermic diet ( martins et al . 2002 ) . in crotalus durissus populations , the low frequency of ectothermic prey could explain such eventual facts .
we placed 40 models in each of the twelve sites to test the prediction that selective predation maintains the color polymorphism in snakes . we had 10 replicates of each combination of color and blotching per site ( = 480 total models ) . models were left in place for a period of 14 d . we secured individual models to rocks with adhesive backed velcro® at approximately 10 m intervals within typical c . l . lepidus habitat . where possible , models were placed along a single linear transect ( all following the edge of a cliff ) ; and multiple transects were used to accommodate all 40 models when a single linear transect was not possible ( multiple transects stacked above the cliff edge ) . models were randomly placed on rocks with the lowest amount of overhead obstruction ( vegetation , large rock formations , etc . ) as possible .
patrones de alimentación fueron investigados en la composición de la dieta de 452 ejemplares de crotalus durissus de brasil central . treinta y tres ítems fueron registrados , correspondientes a cuatro categorías : roedores ( 75 . 76 % ) , marsupiales ( 6 . 6 % ) , mamíferos no identificados ( 9 . 09 % ) y reptiles ( 9 . 09 % ) . los adultos de ambos sexos e individuos jóvenes se alimentaron básicamente de mamíferos , en específico de roedores , esta es la presa más activa y abundante durante todo el año , principalmente en las áreas de cerrado . además fue observado que en c . durissus existe una tendencia a que la dieta de las hembras sea más diversa , factor que podría estar relacionado a las diferencias sexuales que implican diferentes estrategias de alimentación en la biología de esta serpiente cascabel .
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home » resources » categories and criteria » 2001 iucn red list categories and criteria version 3 . 1
see below for the rules and requirements outlined in the iucn red list categories and criteria . version 3 . 1 ( second edition ) . for translations of this document into other languages , click here .
the iucn red list categories and criteria are intended to be an easily and widely understood system for classifying species at high risk of global extinction . the general aim of the system is to provide an explicit , objective framework for the classification of the broadest range of species according to their extinction risk . however , while the red list may focus attention on those taxa at the highest risk , it is not the sole means of setting priorities for conservation measures for their protection .
extensive consultation and testing in the development of the system strongly suggest that it is robust across most organisms . however , it should be noted that although the system places species into the threatened categories with a high degree of consistency , the criteria do not take into account the life histories of every species . hence , in certain individual cases , the risk of extinction may be under - or over - estimated .
before 1994 the more subjective threatened species categories used in iucn red data books and red lists had been in place , with some modification , for almost 30 years . although the need to revise the categories had long been recognized ( fitter and fitter 1987 ) , the current phase of development only began in 1989 following a request from the iucn species survival commission ( ssc ) steering committee to develop a more objective approach . the iucn council adopted the new red list system in 1994 .
to give people using threatened species lists a better understanding of how individual species were classified .
since their adoption by iucn council in 1994 , the iucn red list categories have become widely recognized internationally , and they are now used in a range of publications and listings produced by iucn , as well as by numerous governmental and non - governmental organizations . such broad and extensive use revealed the need for a number of improvements , and ssc was mandated by the 1996 world conservation congress ( wcc res . 1 . 4 ) to conduct a review of the system ( iucn 1996 ) . this document presents the revisions accepted by the iucn council .
the proposals presented in this document result from a continuing process of drafting , consultation and validation . the production of a large number of draft proposals has led to some confusion , especially as each draft has been used for classifying some set of species for conservation purposes . to clarify matters , and to open the way for modifications as and when they become necessary , a system for version numbering has been adopted as follows :
version 1 . 0 : mace and lande ( 1991 ) the first paper discussing a new basis for the categories , and presenting numerical criteria especially relevant for large vertebrates .
version 2 . 0 : mace et al . ( 1992 ) a major revision of version 1 . 0 , including numerical criteria appropriate to all organisms and introducing the non - threatened categories .
version 2 . 1 : iucn ( 1993 ) following an extensive consultation process within ssc , a number of changes were made to the details of the criteria , and fuller explanation of basic principles was included . a more explicit structure clarified the significance of the non - threatened categories .
version 2 . 2 : mace and stuart ( 1994 ) following further comments received and additional validation exercises , some minor changes to the criteria were made . in addition , the susceptible category present in versions 2 . 0 and 2 . 1 was subsumed into the vulnerable category . a precautionary application of the system was emphasised .
version 2 . 3 : iucn ( 1994 ) iucn council adopted this version , which incorporated changes as a result of comments from iucn members , in december 1994 . the initial version of this document was published without the necessary bibliographic details , such as date of publication and isbn number , but these were included in the subsequent reprints in 1998 and 1999 . this version was used for the 1996 iucn red list of threatened animals ( baillie and groombridge 1996 ) , the world list of threatened trees ( oldfield et al 1998 ) and the 2000 iucn red list of threatened species ( hilton - taylor 2000 ) .
version 3 . 0 : iucn / ssc criteria review working group ( 1999 ) following comments received , a series of workshops were convened to look at the iucn red list criteria following which , changes were proposed affecting the criteria , the definitions of some key terms and the handling of uncertainty .
version 3 . 1 : iucn ( 2001 ) the iucn council adopted this latest version , which incorporated changes as a result of comments from the iucn and ssc memberships and from a final meeting of the criteria review working group , in february 2000 .
all new assessments from january 2001 should use the latest adopted version and cite the year of publication and version number .
in the rest of this document , the proposed system is outlined in several sections . section ii , the preamble , presents basic information about the context and structure of the system , and the procedures that are to be followed in applying the criteria to species . section iii provides definitions of key terms used . section iv presents the categories , while section v details the quantitative criteria used for classification within the threatened categories . annex i provides guidance on how to deal with uncertainty when applying the criteria ; annex ii suggests a standard format for citing the red list categories and criteria ; and annex iii outlines the documentation requirements for taxa to be included on iucn ' s global red lists . it is important for the effective functioning of the system that all sections are read and understood to ensure that the definitions and rules are followed .
the information in this section is intended to direct and facilitate the use and interpretation of the categories ( critically endangered , endangered , etc . ) , criteria ( a to e ) , and subcriteria ( 1 , 2 , etc . ; a , b , etc . ; i , ii , etc . ) .
extinction is a chance process . thus , a listing in a higher extinction risk category implies a higher expectation of extinction , and over the time - frames specified more taxa listed in a higher category are expected to go extinct than those in a lower one ( without effective conservation action ) . however , the persistence of some taxa in high - risk categories does not necessarily mean their initial assessment was inaccurate .
all taxa listed as critically endangered qualify for vulnerable and endangered , and all listed as endangered qualify for vulnerable . together these categories are described as ' threatened ' . the threatened categories form a part of the overall scheme . it will be possible to place all taxa into one of the categories ( see figure 1 ) .
for listing as critically endangered , endangered or vulnerable there is a range of quantitative criteria ; meeting any one of these criteria qualifies a taxon for listing at that level of threat . each taxon should be evaluated against all the criteria . even though some criteria will be inappropriate for certain taxa ( some taxa will never qualify under these however close to extinction they come ) , there should be criteria appropriate for assessing threat levels for any taxon . the relevant factor is whether any one criterion is met , not whether all are appropriate or all are met . because it will never be clear in advance which criteria are appropriate for a particular taxon , each taxon should be evaluated against all the criteria , and all criteria met at the highest threat category must be listed .
the different criteria ( a - e ) are derived from a wide review aimed at detecting risk factors across the broad range of organisms and the diverse life histories they exhibit . the quantitative values presented in the various criteria associated with threatened categories were developed through wide consultation , and they are set at what are generally judged to be appropriate levels , even if no formal justification for these values exists . the levels for different criteria within categories were set independently but against a common standard . broad consistency between them was sought .
the criteria for the threatened categories are to be applied to a taxon whatever the level of conservation action affecting it . it is important to emphasise here that a taxon may require conservation action even if it is not listed as threatened . conservation actions which may benefit the taxon are included as part of the documentation requirements ( see annex 3 ) .
taxa at risk from threats posed by future events of low probability but with severe consequences ( catastrophes ) should be identified by the criteria ( e . g . small distributions , few locations ) . some threats need to be identified particularly early , and appropriate actions taken , because their effects are irreversible or nearly so ( e . g . , pathogens , invasive organisms , hybridization ) .
the data used to evaluate taxa against the criteria are often estimated with considerable uncertainty . such uncertainty can arise from any one or all of the following three factors : natural variation , vagueness in the terms and definitions used , and measurement error . the way in which this uncertainty is handled can have a strong influence on the results of an evaluation . details of methods recommended for handling uncertainty are included in annex 1 , and assessors are encouraged to read and follow these principles .
in general , when uncertainty leads to wide variation in the results of assessments , the range of possible outcomes should be specified . a single category must be chosen and the basis for the decision should be documented ; it should be both precautionary and credible .
when data are very uncertain , the category of ' data deficient ' may be assigned . however , in this case the assessor must provide documentation showing that this category has been assigned because data are inadequate to determine a threat category . it is important to recognize that taxa that are poorly known can often be assigned a threat category on the basis of background information concerning the deterioration of their habitat and / or other causal factors ; therefore the liberal use of ' data deficient ' is discouraged .
listing in the categories of not evaluated and data deficient indicates that no assessment of extinction risk has been made , though for different reasons . until such time as an assessment is made , taxa listed in these categories should not be treated as if they were non - threatened . it may be appropriate ( especially for data deficient forms ) to give them the same degree of attention as threatened taxa , at least until their status can be assessed .
all assessments should be documented . threatened classifications should state the criteria and subcriteria that were met . no assessment can be accepted for the iucn red list as valid unless at least one criterion is given . if more than one criterion or subcriterion is met , then each should be listed . if a re - evaluation indicates that the documented criterion is no longer met , this should not result in automatic reassignment to a lower category of threat ( downlisting ) . instead , the taxon should be re - evaluated against all the criteria to clarify its status . the factors responsible for qualifying the taxon against the criteria , especially where inference and projection are used , should be documented ( see annexes 2 and 3 ) . the documentation requirements for other categories are also specified in annex 3 .
the category of threat is not necessarily sufficient to determine priorities for conservation action . the category of threat simply provides an assessment of the extinction risk under current circumstances , whereas a system for assessing priorities for action will include numerous other factors concerning conservation action such as costs , logistics , chances of success , and other biological characteristics of the subject .
re - evaluation of taxa against the criteria should be carried out at appropriate intervals . this is especially important for taxa listed under near threatened , data deficient and for threatened taxa whose status is known or suspected to be deteriorating .
a taxon may be moved from a category of higher threat to a category of lower threat if none of the criteria of the higher category has been met for five years or more .
if the original classification is found to have been erroneous , the taxon may be transferred to the appropriate category or removed from the threatened categories altogether , without delay ( but see point 10 above ) .
the term ' population ' is used in a specific sense in the red list criteria that is different to its common biological usage . population is here defined as the total number of individuals of the taxon . for functional reasons , primarily owing to differences between life forms , population size is measured as numbers of mature individuals only . in the case of taxa obligately dependent on other taxa for all or part of their life cycles , biologically appropriate values for the host taxon should be used .
subpopulations are defined as geographically or otherwise distinct groups in the population between which there is little demographic or genetic exchange ( typically one successful migrant individual or gamete per year or less ) .
the number of mature individuals is the number of individuals known , estimated or inferred to be capable of reproduction . when estimating this quantity , the following points should be borne in mind :
mature individuals that will never produce new recruits should not be counted ( e . g . densities are too low for fertilization ) .
in the case of populations with biased adult or breeding sex ratios , it is appropriate to use lower estimates for the number of mature individuals , which take this into account .
where the population size fluctuates , use a lower estimate . in most cases this will be much less than the mean .
reproducing units within a clone should be counted as individuals , except where such units are unable to survive alone ( e . g . corals ) .
in the case of taxa that naturally lose all or a subset of mature individuals at some point in their life cycle , the estimate should be made at the appropriate time , when mature individuals are available for breeding .
re - introduced individuals must have produced viable offspring before they are counted as mature individuals .
generation length is the average age of parents of the current cohort ( i . e . newborn individuals in the population ) . generation length therefore reflects the turnover rate of breeding individuals in a population . generation length is greater than the age at first breeding and less than the age of the oldest breeding individual , except in taxa that breed only once . where generation length varies under threat , the more natural , i . e . pre - disturbance , generation length should be used .
a reduction is a decline in the number of mature individuals of at least the amount ( % ) stated under the criterion over the time period ( years ) specified , although the decline need not be continuing . a reduction should not be interpreted as part of a fluctuation unless there is good evidence for this . the downward phase of a fluctuation will not normally count as a reduction .
a continuing decline is a recent , current or projected future decline ( which may be smooth , irregular or sporadic ) which is liable to continue unless remedial measures are taken . fluctuations will not normally count as continuing declines , but an observed decline should not be considered as a fluctuation unless there is evidence for this .
extreme fluctuations can be said to occur in a number of taxa when population size or distribution area varies widely , rapidly and frequently , typically with a variation greater than one order of magnitude ( i . e . a tenfold increase or decrease ) .
the phrase ' severely fragmented ' refers to the situation in which increased extinction risk to the taxon results from the fact that most of its individuals are found in small and relatively isolated subpopulations ( in certain circumstances this may be inferred from habitat information ) . these small subpopulations may go extinct , with a reduced probability of recolonization .
extent of occurrence is defined as the area contained within the shortest continuous imaginary boundary which can be drawn to encompass all the known , inferred or projected sites of present occurrence of a taxon , excluding cases of vagrancy ( see figure 2 ) . this measure may exclude discontinuities or disjunctions within the overall distributions of taxa ( e . g . large areas of obviously unsuitable habitat ) ( but see ' area of occupancy ' , point 10 below ) . extent of occurrence can often be measured by a minimum convex polygon ( the smallest polygon in which no internal angle exceeds 180 degrees and which contains all the sites of occurrence ) .
figure 2 . two examples of the distinction between extent of occurrence and area of occupancy . ( a ) is the spatial distribution of known , inferred or projected sites of present occurrence . ( b ) shows one possible boundary to the extent of occurrence , which is the measured area within this boundary . ( c ) shows one measure of area of occupancy which can be achieved by the sum of the occupied grid squares .
the term ' location ' defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present . the size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations . where a taxon is affected by more than one threatening event , location should be defined by considering the most serious plausible threat .
a quantitative analysis is defined here as any form of analysis which estimates the extinction probability of a taxon based on known life history , habitat requirements , threats and any specified management options . population viability analysis ( pva ) is one such technique . quantitative analyses should make full use of all relevant available data . in a situation in which there is limited information , such data as are available can be used to provide an estimate of extinction risk ( for instance , estimating the impact of stochastic events on habitat ) . in presenting the results of quantitative analyses , the assumptions ( which must be appropriate and defensible ) , the data used and the uncertainty in the data or quantitative model must be documented .
extinct ( ex ) a taxon is extinct when there is no reasonable doubt that the last individual has died . a taxon is presumed extinct when exhaustive surveys in known and / or expected habitat , at appropriate times ( diurnal , seasonal , annual ) , throughout its historic range have failed to record an individual . surveys should be over a time frame appropriate to the taxon ' s life cycle and life form .
extinct in the wild ( ew ) a taxon is extinct in the wild when it is known only to survive in cultivation , in captivity or as a naturalized population ( or populations ) well outside the past range . a taxon is presumed extinct in the wild when exhaustive surveys in known and / or expected habitat , at appropriate times ( diurnal , seasonal , annual ) , throughout its historic range have failed to record an individual . surveys should be over a time frame appropriate to the taxon ' s life cycle and life form .
critically endangered ( cr ) a taxon is critically endangered when the best available evidence indicates that it meets any of the criteria a to e for critically endangered ( see section v ) , and it is therefore considered to be facing an extremely high risk of extinction in the wild .
endangered ( en ) a taxon is endangered when the best available evidence indicates that it meets any of the criteria a to e for endangered ( see section v ) , and it is therefore considered to be facing a very high risk of extinction in the wild .
vulnerable ( vu ) a taxon is vulnerable when the best available evidence indicates that it meets any of the criteria a to e for vulnerable ( see section v ) , and it is therefore considered to be facing a high risk of extinction in the wild .
near threatened ( nt ) a taxon is near threatened when it has been evaluated against the criteria but does not qualify for critically endangered , endangered or vulnerable now , but is close to qualifying for or is likely to qualify for a threatened category in the near future .
least concern ( lc ) a taxon is least concern when it has been evaluated against the criteria and does not qualify for critically endangered , endangered , vulnerable or near threatened . widespread and abundant taxa are included in this category .
not evaluated ( ne ) a taxon is not evaluated when it is has not yet been evaluated against the criteria .
note : as in previous iucn categories , the abbreviation of each category ( in parenthesis ) follows the english denominations when translated into other languages ( see annex 2 ) .
( e ) the effects of introduced taxa , hybridization , pathogens , pollutants , competitors or parasites .
e . quantitative analysis showing the probability of extinction in the wild is at least 50 % within 10 years or three generations , whichever is the longer ( up to a maximum of 100 years ) .