crangon franciscorum is a species of shrimp in the crangonidae family which is endemic to the brackish estuaries of california , and found from puget sound in the north to san diego , california in the south .

the species is especially abundant in san francisco bay , despite population fluctuations due to environmental stresses .

its common names include bay shrimp , sand shrimp , common shrimp , grass shrimp , black shrimp , california shrimp and black tailed shrimp .

the species has been commercially fished from 1869 to the present .

crangon franciscorum

the toxicity of kelthane to the grass shrimp ( crangon franciscorum ) . - pubmed - ncbi
sitts r . m . , a . w . knight . 1979 . predation by the estuarine shrimps crangon franciscorum stimpson and palaemon macrodactylus rathbun . biological bulletin 156 : 356 - 368 .
the distribution , abundance , and diet of crangon franciscorum and c . nigricauda were estimated from 15 monthly samples from the channel and shallows of san pablo bay . crangon franciscorum outnumbered c . nigricauda by an overall ratio of 10 : 1 . the majority of the c . nigricauda ( 85 % ) were taken in the high salinity waters of the channel . most of the c . franciscorum catch ( 68 % ) came from the low salinity shallows . this species concentrated only in the channel when reproductive in the winter .
california bay shrimp , crangon franciscorum ( or
grass shrimp
as they are more commonly known ) are primarily harvested in sf bay ( although a few talented perch anglers know how to catch them in the surf ) . the shrimp in jack london ' s tale of the fish patrol is the grass this guy . here ' s a few snippets from an article i wrote last year about grass shrimp :
crago franciscorum is found from alaska to san diego . it can be distinguished by the narrow chelipeds or hands in which the finger when bent is almost parallel with the hand . the length of the hands is approximately 4½ times the width . the color is a mottled yellowish gray . large specimens are a trifle over 3 inches in length .
three species of shrimps make up the bulk of the commercial catch . these are all members of the genus crago . they are found in the catches in the following order of relative abundance : c . franciscorum , c . nigricauda , and c . nigromaculata . this order varies a little seasonally ; nigricauda and nigromaculata changing places occasionally in the late summer . other shrimps are found occasionally in the catches . pandalus danae , the shrimp which supports a good part of the alaskan fishery , is represented by a few specimens . spirontocaris cristata , a small red species , occurs in considerable numbers but is too small for any commercial use . occasionally considerable numbers of upogebia pugettensis , a burrowing ghost shrimp , are found .
stimpson , w . ( 1856 ) . on some californian crustacea . proceedings of the california academy of sciences . 1 : 87 - 90 . [ details ]
de grave , s . & c . h . j . m . fransen . ( 2011 ) . carideorum catalogus : the recent species of the dendrobranchiate , stenopodidean , procarididean and caridean shrimps ( crustacea : decapoda ) . zool . med . leiden . 85 ( 9 ) : 30 . ix . 2011 : 195 - 589 figs 1 - 59 . ( look up in imis ) [ details ] available for editors [ request ]
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fishing for shrimp in san francisco bay started about 1869 . the first fishermen were italians and there were 8 boats engaged in the fishery . they used small meshed seines 60 feet long and 8 feet deep with a bag in the center . the nets were used in deep water and took very few small shrimp or fish . they usually took from 50 to 75 pounds of shrimp in a haul and made from 3 to 5 hauls on each tide .
shrimp fishing is carried on under several methods of organization . frank spenger company and quan brothers maintain their own camps and buy the shrimps from the trawlers , who fish for them at a definite price per pound . the fishermen in this case have no more interest in the shrimps after they have delivered them . the chinese camps in south san francisco are organized under three working plans . the larger number of camps are owned by chinese companies maintaining offices in chinatown . these camps are leased to a group of men who work on shares among themselves . the company which owns the camp is paid for its use by handling the total catch at a definite price which allows it a profit . the price paid to the camps for fresh shrimps , for
instance , has been 5½ cents per pound for a number of years . the camp crew maintains the boats , gear and buildings , and manages its own commissary as a community affair . one man is usually camp boss and has the responsibility of supervising the activities of the camp . there are two camps which depart from this procedure . in one of these , two
fig . 1 . chinese shrimp nets drying at hunter ' s point near san francisco . photo by paul bonnot , november , 1930
men own the camp and gear and pay definite wages and found to the crew , and in the other , two men own the boat and gear and work in partnership , sometimes hiring a third man .
the present day camps vary from a 2 man outfit fishing 20 nets to a camp of 8 men using 50 nets .
the first of september is the beginning of the fiscal year in the camps . at this time the shareholders are at liberty to break away if they choose and go to some other camp . very few groups stay together more than a year , and there is considerable shifting around , though few men leave the fishery and very few new men come in .
the beds maintained by each company are held from year to year . they were originally laid out on a first - come - first - served basis . there are unwritten rules concerning the staking of new beds . a new bed must be far enough away so it will not
cork
an old bed .
claim jumping
is rare , but a controversy over this between two large companies nearly precipitated a tong war in 1930 . the matter was , however , amicably arranged . a bed does not necessarily have to be operated to be held . the larger companies generally have two or more beds , although they seldom work more than one . in some portions of the bay the beds can be used only during the summer due to weather conditions , and these are left idle during the winter .
the chinese shrimp nets are hand - made and imported from china . the best ones are made of hemp , while some are constructed of a twisted grass - like fiber . they are 40 feet long and shaped like a cone . the round mouth is tied in the form of a rectangle 4 by 30 feet . the last 8
or 10 feet of the small end is a cylinder about 18 inches in diameter . the small end is made of american cotton twine ( 9 - strand ) and is of 1 - inch mesh . the mesh of the larger portion of the net is from 3½ inches at the mouth to 1 inch where the final section is attached . this diminution of mesh is gradual , the net being in one piece and not made up of sections of webbing of gradually decreasing sizes .
the nets are fished for ten days or two weeks and are then washed and dried before being used again . about once every six weeks or two months the nets are soaked in a solution of tan bark and dried . after five or six of these tannings they are put in a large wooden hopper , built over the cooking tank , steamed and again dried . with careful handling , nets will last three or four years . during the winter and spring when the catch is normally light the new nets are stored and the older patched nets are used .
the shrimp beds are laid out at right angles to the tide flow in from 6 to 10 fathoms of water . anchor pins are driven into the mud 30 feet apart . at each end of the string of anchors another is driven , in line with the string and spaced 90 feet from the last at that end . the anchor pins are driven by a long wooden pole which has at its larger end a length of iron pipe . the pins are driven some distance into the mud . from each anchor a rope runs to a brail . the length of rope varies with the depth of water ( 8 fathoms of water , 180 feet of rope ) . each brail is slung to its anchor line by a bridle , 28 feet long ( included in the 180 feet ) . the brails are tied together by a rope which is clove - hitched to their centers . another rope runs along the string of brails half way between the top and center , being looped and pinned to each and attached to a keg buoy at each end . the nets are fastened to the bottom rings of the brails by slip knots and to the top rings by loops and wooden pins . the pins are connected to each other by a quarter - inch rope which is attached at each end to the buoy line . ( see fig . 3 . ) the reason for this will appear later .
the most efficient bed is laid out at an exact right angle to the tide flow . ( see fig . 4 . ) if the angle of the flood tide varies from that of the ebb , due , perhaps , to an outthrust of the shore line , the bed must be made to compromise between the two , or if the angle is too great , it can be used for one tide only . in a clear channel where the tide runs back and forth on the same line a bed will fish both tides . the ground tackle , anchors , ropes and brails are left down for the season , and , though the brails and anchors are reclaimed , the rope is left on the bottom or picked up and thrown away . the rope used is three - quarter - inch manila , and a bed to accommodate 50 or 60 nets represents several miles of rope which is used only one season .
the nets are set at slack water . the first brail is lifted by bringing in the buoy line with the winch . one side of the net is attached , the next brail is brought in and the other side of the net attached and one side of the next net . the whole string is run in this manner . the brails and the attached nets are let down on one side of the boat while the brails are brought up on the other side . when picking up the nets the same procedure is used . the pins which attach the nets to the top rings are important in lifting the nets . the lifting is started before the tide has stopped running . as it would be difficult to raise the nets with the mouths wide open to the force of the tide , after the brail has been lifted from the bottom a jerk on the quarter - inch line pulls out the wooden pin and releases the top of the net and the rectangular opening collapses . the net is attached only to the bottom rings and so comes up flattened out . a pull on the slip knot and the net is free to be pulled in by several men . if the catch is heavy the small end of the net will be stretched into the shape of a large ball . when too heavy to be lifted by hand a tackle is used . a cord is wound about the small end and tied with a slip knot . a pull on this and the catch is dumped into the shrimp bin or into baskets . the nets are left down
for the entire run of the tide , five to eight hours , as it would be impossible to lift them when the tide is running strong . the nets must be lifted at each change of the tide . the ground tackle can swing around and face either tide but the nets would become tangled . five or six men are necessary to handle a large number of nets as the time in which they can be set or lifted is limited .
in 1914 frank spenger of berkeley introduced the shrimp trawl in the north end of san francisco bay . this net is a beam trawl . the mouth is a rectangle , 20 by 2½ feet , held open by brails and a wooden pole . the side wings are 20 feet long . the net is 60 feet long and tapers to about a foot in diameter at the small end . the wings are of 2 - inch mesh ; the next 20 feet are of 1⅜ - inch mesh ; and the last 20 feet are of 1 - inch mesh . over the small mesh is generally a coarse piece of webbing of 5 - inch mesh as chaffing gear . the lead line is made up of old webbing rolled and lashed with twine to form a
rope
about 2 inches in diameter which will not dig into the bottom . the lead line sets about 10 inches behind the cork line when fishing . the brails at the end of each wing are 2 feet , 6 inches long , and slide on flat iron shoes which turn up in front . ( see
about 4 inches wide . the trawls are pulled with the tide at about 3 miles an hour , in from 1 to 5 fathoms of water . a drag of a mile or more is made , then the net is lifted with the aid of a short boom , the small end untied and the catch dumped on deck . the boat is put about and started back to the starting point . while making the run back the catch is sorted and put into baskets . these are one - man rigs . each man has two nets which are used alternately , one being used while the other is laid out for repairs or drying .
the early shrimp fishing was done entirely with the chinese junk . these boats were about 50 feet long , with square sterns and blunt bows , and were propelled by the chinese slatted sail and later by an ordinary
fig . 6 . the shrimp trawl . photo by r . steele , november , 1921
canvas sail . the large wooden rudder could be lifted when not in use . there was a space for the nets and another for the catch . a space in the bow was left clear to handle the nets . a reel with 4 spokes at each end was used as a windlass to manipulate the fishing gear . one or two men worked this windlass .
fig . 7 . city shrimp company junk at hunter ' s point near san francisco . photo by paul bonnot , january , 1931
the present day fishery utilizes several types of boats . the old style junk is still used in some cases , with the mast cut down and rigged as a hoisting boom ; the hoisting winch is operated by a small gas engine and motive power supplied by a tow boat . this type of boat is towed to the fishing ground and left there . the tow boat goes out for it about the time the nets are lifted at the end of the tide . a modification of these boats is the power junk with from 30 - to 50 - horsepower gas or
fig . 8 . golden west shrimp junk at hunter ' s point near san francisco . photo by paul bonnot , january , 1931
oil engines . these have a pilot house and cabin built toward the stern over the engine room . there is only one company at present which uses the hand reel for lifting the nets . the beam - trawlers in the northern part of san francisco bay are ordinary 30 - to 40 - foot fishing boats , fitted with a short stubby mast and boom to facilitate the lifting of the net and catch from the water .
in the early days of the fishery , many more men were employed than there are today . some of the old camps maintained three distinct crews—a day boat crew , a night boat crew , and a shore crew that cooked and cared for the shrimps which the boat crews brought in . today all this is changed . the frank spenger company and quan brothers , with a crew of 3 or 4 men , handle the shrimp brought in by their fishermen ; and the crews of from 2 to 6 men in a chinese camp catch and also prepare the shrimps .
a chinese shrimp camp during the height of the season is a busy place . the boats fish 3 tides , so one haul is generally at night . as soon as the shrimps are landed in round baskets , weighing from 70 to 90 pounds each , the crew goes to eat . one man is generally left ashore as camp tender and he prepares the meal and starts a fire under the shrimp boiler . as soon as the men have finished eating they start boiling the shrimps . several baskets of shrimps are dumped into the boiling tank with several scoop - shovels of coarse salt . the shrimps are boiled for about 15 minutes , scooped up with shallow brails made of copper wire and put again into baskets . the steaming baskets are dumped on benches made of square - meshed galvanized wire and several of the crew start at once to screen the shrimps . this is done by shaking a quantity of shrimps in a hand screen made of a wooden barrel hoop and square - meshed wire which varies in size from one - half to three - quarters of an inch . the small shrimps fall through and are spread on the outdoor drying floors . the larger ones are put into barrels and
sent to chinatown to be hand - picked by chinese women and girls . if the market demand is small , a 4 - inch cylinder of galvanized wire is placed in the center of the barrel for ventilation and the barrel sent to cold storage where it is frozen solid until the market improves or the camps fail to make further catches .
the shrimps put out to dry remain on the drying floor for several days . they are turned at intervals . when dried a heavy cleated wooden roller is pushed back and forth over them to break the meat from the shell . after being sufficiently broken up , the whole mass is put into baskets and dumped into a fanning machine . this is a wooden arrangement with a large enclosed wooden fan which sends a strong current of air through a long box , square in cross - section . as the broken shrimps drop into the air current , the heads and shells , being much lighter than the solid meat , are blown out at the end of the box while the meat falls to the bottom and into baskets placed there to receive it . after hand - picking the meat for fish scrap and bone , the dried shrimp meat is ready for market .
quan brothers , near mcnear ' s point in marin county , process their shrimps in the same manner as the other chinese camps , with the exception of the use of a mechanical shaker over which the shrimps are passed as they come from the boiling tank . this does away with hand - screening . frank spenger company at san quentin point in marin county , has a very up - to - date plant . every device for saving labor has been installed . the shrimps are dumped into the boiler which consists of a large iron tank which nests inside of another tank . when the shrimps are cooked the inside tank is raised and tipped over by a tackle . the shrimps go into a hopper which feeds them to an endless belt by which they are lifted to the second floor . here they go into a large mechanical shaker which separates the large from the small . the larger ones , which are sold fresh , go down a chute to a table where they are hand - picked for culls . the small ones are piled on a long table covered with square - meshed wire . this table has a raised center and has under it a wooden box from which a current of hot air is forced up
through the shrimps . this method of drying eliminates any waste due to rain or bad weather and is faster than sun - drying . the dried shrimps in this case are run into a rotary tumbler which breaks them up , and they are then fed through a blower of the same general construction as those used in the chinese camps except that it is much larger and can therefore handle many more shrimps in a given time .
sund - dried shrimps lose three - fifths of their weight in the process . the dried material yields one - third shrimp meats and two - thirds shrimp meal by weight . the shrimp meat is shipped to china and used locally for human consumption . the shrimp meal , consisting of broken and ground shells and meat , is sold for fertilizer and for fish food .
crago nigricauda , the black - tailed shrimp , occurs from alaska to lower california . it is a dark gray with a blackish tail . the hand is a little more than twice as long as wide . the finger when bent is almost at right angles to the hand . the length of this species is about 2½ inches .
crago nigromaculata seems to be a more local species . it resembles c . nigricauda , the hands being the same . most specimens are a bluish fawn color with a round spot of blue enclosed by a black and a yellow ring on each side of the sixth abdominal segment .
little is known concerning the life history of these shrimps . eggs may be found attached to the swimmerettes of the females during the whole year . these eggs are in all stages , from newly laid ones , showing no internal structure , through several stages . the oldest eggs contain small shrimps nearly through the zoea stage . there are no available records of young shrimps being taken with the catches . the catches sometimes contain vast numbers of a schizopod ( euphausia pacifica ) which might be mistaken for small shrimps . schizopods , however , can easily be distinguished by their eight pairs of biramous legs .
on the carapace ( thorax ) of many of the cragos will be found a smooth bean - shaped lump . this is caused by a parasitic isopod
( argeia pauperata ) . the lump is part of the continuous surface of the chitonous covering of the shrimp , and is shed with the rest during the molt . the isopod is imprisoned therefore between the hard outer covering and the gill chamber . on opening one of these lumps the female isopod will be found nearly filling the cavity . the female is nearly round , has no eyes and the legs have degenerated to short hooked affairs . on the dorsal surface is the brood pouch , which has overlapping flaps which fit together like the shutters of a camera . this pouch is generally filled with young isopods . a small male will be found with the female . he is only about one - tenth the bulk of the female . he has functional legs and eye spots , and is shaped like a long parallelogram with rounded ends .
the chinese shrimp nets take many different species of fish , most of them occurring in small numbers . the appended list shows their relative abundance . the edible fishes are eaten by the chinese or given away to others for food . during the winter and spring the shrimp nets sometimes take vast numbers of the hydroid medusa polochis . these will occasionally outnumber the shrimp , making up 75–80 per cent of the catch . there are , of course , a great many other species of the lower forms represented .
the following tables 4 and 5 and figures 9 and 10 show the amounts of shrimps caught in san francisco bay during the period , 1915–1930 , inclusive .
during 1920–1921 ( december 12 , 1920–march 15 , 1921 ) , the division of fish and game issued a permit to paul skrmetti of san pedro to fish for shrimps with a trawl in southern california waters . skrmetti came from florida , where he had engaged in shrimp fishing . he used for his experimental fishing the small otter trawl with which much of the florida shrimping is done . the division of fish and game required that he keep a record of his hauls , and the following data are derived from his records :
of other fish . the amount of shrimps taken did not justify the effort and the permit was canceled after a four - month trial .
the shrimps taken were some species of either pandalus or peneus , but as no specimens were kept and no record made of the species , i am not certain whether there were one or more than one species involved .
many fish of different species were also taken in these hauls . these are all enumerated by the common names , some of which are not familiar to me . the following list gives the relative weights for the experiment :
during the latter part of 1930 several fishermen at monterey accidentally took a few large specimens of pandalus platyceros in their octopus traps . they made serious attempts to capture more of the shrimps and succeeded for some time in landing 50 to 150 pounds a day . the traps used were round , bottle - shaped affairs , made of bamboo , 5 feet long and 3 feet in diameter , with a funnel at the larger end . the fishing was carried on about 4 miles southwest of point
fig . 11 . octopus trap at monterey . this type of trap with modifications , is being used to take shrimps in deep water . photo by paul bonnot , november , 1930
cypress , monterey county , in 150 fathoms of water . the shrimps ran very large , averaging about 8 inches in length and 6 to the pound . several men fished for the shrimps after the first fishermen were successful , but due to the difficulty of working in such deep water and a storm which destroyed most of the traps , the majority of the men went back to other types of fishing .
hynes , f . w . 1929 . the shrimp fishery of southeastern alaska . u . s . bur . fish . , rept . [ for 1929 ] app . i , doc . 1052 , p . 1–18 , 9 figs . orr , arthur 1923 . the american shrimp industry .
tressler , donald k . , marine products of commerce . new york , p . 548–560 . rathbun , richard . 1883 . notes on the shrimp and prawn fisheries of the united states . u . s . fish comm . , bull . [ for 1882 ] vol . 2 , p . 139–152 . 1887 . the shrimp and prawn fisheries .
fisheries and fishery industries of the united states . washington , sec . 5 , vol . 2 , pt . 21 , p . 799–810 . schmitt , waldo l . 1921 . the marine decapod crustacea of california . univ . calif . publ . zool . , vol . 23 , 470 p . , 50 pls . scofield , n . b . 1919 . shrimp fisheries of california . calif . fish and game , vol . 5 , no . 1 , p . 1–12 , 5 figs . smiley , charles w . , ed . 1887 . notes upon fish and the fisheries : preparation of shrimps in china . u . s . fish comm . , bull . [ for 1886 ] vol . 6 , p . 451 . townsend , c . h . 1901 . the chinese shrimp fishery of san francisco bay . u . s . comm . fish . , rept . [ for 1900 ] p . 182–184 . tulian , e . a . 1923 . the present status of the lousiana shrimp industry . american fish . soc . , trans . , 53 . meet . , p . 110–121 , illus . vilbrandt , f . c . and abernethy , r . f . 1930 . utilization of shrimp waste . u . s . bur . fish . , rept . [ 1930 ] , app . vi , doc . 1078 , p 101–122 , 3 figs . , 7 tables . walsh , r . f . 1893 . chinese and the fisheries . calif . ill . mag . , vol . 4 , no . 6 , nov . , p . 833–840 .
[ * ] no . 1 . report on fish conditions . 1913 ; 48 pp . , 3 figs . contains :
the towing of salmon and steelhead fry from sacramento to the sea in a
live car .
by n . b . scofield .
investigation of the life history of the edible crab ( cancer magister ) . by f . w . weymouth .
a general report on a quinnat salmon investigation carried on during the spring and summer of 1911 . by n . b . scofield .
trout and black bass planting and transplanting in the san joaquin and southern sierra districts . by a . d . ferguson .
[ * ] no . 2 . the scientific investigation of marine fisheries as related to the work of the fish and game commission in southern california . by will f . thompson : 1919 ; 27 pp . , 4 figs .
[ * ] no . 3 . the spawning of the grunion ( leuresthes tenuis ) . by will f . thompson , assisted by julia bell thompson . july 15 , 1919 ; 29 pp . , 9 figs .
[ * ] no . 4 . the edible clams , mussels and scallops of california . by frank w . weymouth . jan . 10 , 1921 ; 74 pp . , 19 pls . , 26 figs .
[ * ] no . 5 . a key to the families of marine fishes of the west coast . by edwin c . starks . march 3 , 1921 : 16 pp . , 4 figs .
[ * ] no . 6 . a history of california shore whaling . by edwin c . starks . october , 1922 ; 38 pp . , 22 figs .
[ * ] no . 7 . the life history and growth of the pismo clam . by frank w . weymouth . 1923 ; 120 pp . , 15 figs . , 18 graphs .
[ * ] no . 8 . racial and seasonal variation in the pacific herring , california sardine and california anchovy . by carl l . hubbs . february , 1925 ; 23 pp . , 4 pls .
[ * ] no . 9 . preliminary investigation of the purse seine industry of southern california . by tage skogsberg . 1925 ; 95 pp . , 23 figs .
[ * ] no . 10 . the life history of leuresthes tenuis , an atherine fish with tide controlled spawning habits . by frances n . clark . october , 1925 ; 51 pp . , 6 graphs , 7 pls .
no . 11 . the california sardine . by the staff of the california state fisheries laboratory . 1926 ; 221 pp . , 74 figs .
thompson , will f . the california sardine and the study of the available supply .
sette , oscar elton . sampling the california sardine : a study of the adequacy of various systems at monterey .
higgins , elmer h . a study of fluctuations in the sardine fishery at san pedro .
thompson , will f . errors in the method of sampling used in the study of the california sardine .
scofield , w . l . the sardine at monterey ; dominant size classes and their progression , 1919–1923 .
no . 12 . the weight - length relationship of the california sardine ( sardina caerulea ) at san pedro . by frances n . clark . 1928 ; 58 pp . , 11 figs .
no . 13 . the seasonal average length trends at monterey of the california sardine ( sardina caerulea ) . by carroll b . andrews . 1928 ; 13 pp . , 6 figs .
[ * ] no . 14 . report on the seals and sea lions of california . by paul bonnot . 1928 ; 61 pp . , 38 figs .
[ * ] no . 15 . the commercial fish catch of california for the years 1926 and 1927 . by the bureau of commercial fisheries . 1929 ; 94 pp . , 52 figs .
no . 16 . the life - history of the california jack smelt , atherinopsis californiensis . by frances n . clark . 1929 ; 22 pp . , 12 figs .
no . 17 . sacramento - san joaquin salmon ( oncorhynchus tschawytscha ) fishery of california . by g . h . clark . 1929 ; 73 pp . , 32 figs .
no . 18 . the pismo clam : further studies of its life - history and depletion . by william c . herrington . 1930 ; 67 pp . , 16 figs .
no . 19 . sardine fishing methods at monterey , california . by w . l . scofield , 1929 ; 61 pp . , 27 figs .
[ * ] no . 20 . the commercial fish catch of california for the year 1928 . by the staff of the bureau of commercial fisheries . 1930 ; 109 pp . , 62 figs .
no . 21 . analysis of boat catches of white sea bass ( cynoscion nobilis ) at san pedro , california . by s . s . whitehead . 1930 ; 26 pp . , 20 figs .
no . 22 . a bibliography of the tunas . by genevieve corwin . 1930 ; 103 pp .
no . 23 . success of the purse seine boat in the sardine fishery at monterey , california ( 1929–1930 fishing season ) . by j . b . phillips . 1930 ; 28 pp . , 19 figs .
no . 24 . an analysis of the catch statistics of the striped bass ( roccus lineatus ) fishery of california . by j . a . craig . 1930 ; 41 pp . , 22 figs .
no . 25 . fishing areas along the california coast for the sardine ( sardina caerulea ) . by the california state fisheries laboratory . 1930 ; 44 pp . , 25 figs .
no . 26 . seasonal changes in the daily average length of the california sardine ( sardina caerulea ) . by frances n . clark . 1930 ; 20 pp . , 11 figs .
no . 27 . the ring net , half ring net , or purse lampara in the fisheries of california . by donald h . fry . jr . , 1930 ; 65 pp . , 28 figs .
no . 28 . handbook of common commercial and game fishes of california . by lionel a . walford . 1931 ; 183 pp . , 137 figs .
no . 29 . the striped bass of california . by eugene c . scofield . 1931 ; 82 pp . , 46 figs .
no . 30 . the commercial fish catch of california for the year 1929 . by the staff of the bureau of commercial fisheries . 1931 ; 133 pp . , 75 figs .
no . 31 . studies of the length frequencies of the california sardine ( sardina caerulea ) . by the california state fisheries laboratory . 1931 ; 53 pp . , 24 figs .
no . 32 . the california halibut ( paralichthys californicus ) and an analysis of the boat catches . by g . h . clark . 1931 ; 52 pp . , 25 figs .
no . 33 . fishing methods for the bluefin tuna ( thunnus thynnus ) and an analysis of the catches . by s . s . whitehead . 1931 ; 32 pp . , 22 figs .
no . 34 . salmon of the klamath river , california . by john o . snyder . 1931 ; 130 pp . , 44 figs .
no . 35 . a distributional list of the species of fresh water fishes known to occur in california . by barton w . evermann and howard walton clark . 1931 ; 67 pp .
no . 36 . a bibliography of the sardines . by genevieve c . wheeler . 1931 ; 133 pp .
no . 37 . the california barracuda ( sphyraena argentea ) . by lionel a . walford . 1932 .
no . 38 . the california shrimp industry . by paul bonnot . 1932 ; 20 pp . , 11 figs .
these bulletins are offered free of charge to interested persons and in exchange for the publications of other bodies engaged in marine research . address : california state fisheries laboratory , terminal island , california .
2 . most of the material for this section was taken from
shrimp fisheries of california ,
by n . b . scofield ( 1919 ) .
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science 07 feb 1986 : vol . 231 , issue 4738 , pp . 567 - 573 doi : 10 . 1126 / science . 231 . 4738 . 567
research scientists with the u . s . geological survey , 345 middlefield road ( ms - 999 ) , menlo park , ca 94025 .
the san francisco bay estuary has been rapidly modified by human activity . diking and filling of most of its wetlands have eliminated habitats for fish and waterfowl ; the introduction of exotic species has transformed the composition of its aquatic communities ; reduction of freshwater inflow by more than half has changed the dynamics of its plant and animal communities ; and wastes have contaminated its sediments and organisms . continued disposal of toxic wastes , the probable further reduction in freshwater inflow , and the possible synergy between the two provide the potential for further alteration of the estuary ' s water quality and biotic communities .
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mclaughlin et al . 2005 . common and scientific names of aquatic invertebrates from the united states and canada : crustaceans . american fisheries society special publication 31
williams , austin b . , lawrence g . abele , d . l . felder , h . h . hobbs , jr . , r . b . manning , et al .
disclaimer : itis taxonomy is based on the latest scientific consensus available , and is provided as a general reference source for interested parties . however , it is not a legal authority for statutory or regulatory purposes . while every effort has been made to provide the most reliable and up - to - date information available , ultimate legal requirements with respect to species are contained in provisions of treaties to which the united states is a party , wildlife statutes , regulations , and any applicable notices that have been published in the federal register . for further information on u . s . legal requirements with respect to protected taxa , please contact the u . s . fish and wildlife service .
allen , j . a . , 1966 . the rhythms and population dynamics of decapod crustacea . oceanogr . mar . biol . ann . rev . 4 : 247–265 .
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bonnot , p . , 1932 . the california shrimp industry . calif . dept . fish game , fish bull . 38 , 20 pp .
boothe , p . , 1967 . the food and feeding habits of four species of san francisco bay fish . calif . dept . fish game , mro ref . 67 - 13 , 155 pp .
brienes , m . , 1983 . china camp and the san francisco bay shrimp fishery . calif . dept . parks rec . , july 1983 , 162 pp .
ch2m hill , 1983 . final report , phase ii predischarge oceanographic study ; southwest ocean outfall project , 313 pp .
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ganssle , d . , 1966 . fishes and decapods of the san pablo and suisun bays . in d . w . kelley ( ed . ) , ecological studies of the sacramento - san joaquin estuary , part i . calif . dept . fish game . fish bull . 133 : 64–94 .
gulland , j . a . & b . j . rothschild , 1984 . workshop report . in j . a . gulland & b . j . rothschild ( eds . ) , penaeid shrimps : their biology and management , 308 pp .
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hunt , j . h . , r . j . carroll , v . chinchilli & d . frankenberg , 1980 . relationship between environmental factors and brown shrimp production in pamlico sound , north carolina . spec . sci . rep . n . c . div . mar . fish . april 1980 , 32 pp .
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scofield , n . b . , 1919 . shrimp fisheries of california . calif . fish game 5 : 1–12 .
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thomson , j . m . , 1956 . fluctuations in australian prawn catch . proc . indo - pacific fish . council , 6th session , tokyo , sect . ii & iii : 444–447 .
l . ) in german coastal waters . rapp . p . - v - réun . cons . int . explor . mer , 172 : 250–258 .
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to cite this page : myers , p . , r . espinosa , c . s . parr , t . jones , g . s . hammond , and t . a . dewey . 2018 . the animal diversity web ( online ) . accessed at https : / / animaldiversity . org .
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the mexican blindcat ( prietella phreatophila ) , in spanish bagre de muzquiz , is a species of north american freshwater catfish ( family ictaluridae ) .

until recently , it was believed to be endemic to coahuila in the rio bravo drainage in northern mexico ; however , in 2016 the species was reported from the amistad national recreation area , texas , following earlier , unconfirmed sightings of blind , white catfish in the area .

the captured specimens were brought to the san antonio zoo and aquarium .

prietella phreatophila

kari pihlaviita added the finnish common name
kätköpiikkimonni
to
prietella phreatophila carranza , 1954
.
the bagre de muzquiz or mexican blindcat ( prietella phreatophila ) is a species of north american freshwater catfish endemic to mexico .
discovery of the mexican blindcat , prietella phreatophila , in the u . s . , and an update on its rangewide conservation status
discovery of the mexican blindcat , prietella phreatophila , in the u . s . , and an update . . . - f1000research
discovery of the mexican blindcat , prietella phreatophila , in the u . s . , and an update on its rangewide conservation status
froese , rainer , and daniel pauly , eds . ( 2011 ) .
prietella phreatophila
in fishbase . december 2011 version .
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contreras - balderas , s . & almada - villela , p . 1996 . prietella phreatophila . 2011 iucn red list of threatened species . downloaded on 28 august 2011 .
page , l . and sheehy , g . ( 2007 ) prietella phreatophila carranza 1954 , mexican blindcat . the tree of life web project , arizona . available at : urltoken
amemiya , c . t . , kelsch , s . w . , hendricks , f . s . , & gold , j . r . 1986 . the karyotype of the mexican blindcat , prietella phreatophila carranza ( ictaluridae ) . copeia 4 : 1024 - 1028 .
amemiya , c . t . , kelsch , s . w . , hendricks , f . s . and gold , j . r . ( 1986 ) the karyotype of the mexican blindcat , prietella phreatophila carranza ( ictaluridae ) . copeia , 1986 ( 4 ) : 1024 - 1028 .
hendrickson da , johnson j , sprouse p et al . discovery of the mexican blindcat , prietella phreatophila , in the u . s . , and an update on its rangewide conservation status [ version 1 ; not peer reviewed ] . f1000research 2016 , 5 : 2837 ( slides ) ( doi : 10 . 7490 / f1000research . 1113512 . 1 )
dean hendrickson , curator of ichthyology at the university of texas at austin , identified the live fish , discovered in a deep limestone cave at amistad national recreation area near del rio , texas , as the endangered mexican blindcat ( prietella phreatophila ) . the pair of small catfish , collected by a team in may , have been relocated to the san antonio zoo .
paratype for prietella phreatophila carranza catalog number : usnm 164169 collection : smithsonian institution , national museum of natural history , department of vertebrate zoology , division of fishes preparation : glycerin with bone stain collector ( s ) : c . bolivar & j . carranza year collected : 1954 locality : mexico , coahuila , muzquiz , municipio de muzquiz . , coahuila , mexico , north america
several near - endemic species characterize each section of the ecoregion : devils river minnow ( dionda diaboli ) , spotted minnow ( d . melanops ) , and mexican red shiner ( cyprinella rutila ) in the san juan , río salado darter ( etheostoma segrex ) in the salado de nadadores , salado shiner ( notropis saladonis ) in the río salado , and mexican blindcat ( prietella phreatophila ) in subterranean waters . the salado shiner is the only species considered to be a strict endemic to the ecoregion .
hendrickson , d . a . , j . k . krejca and j . m . r . martinez . in press . mexican blindcats , genus prietella ( siluriformes : ictaluridae ) : an overview of recent explorations . environmental biology of fishes .
the blind cave catfish , prietella phreatophila : ictaluridae , is a rare species that is nearly entirely unstudied , with very little known about its basic biology and conservation status . i propose to use nanfa funding to carry out an expedition that will involve : 1 . a mark - recapture study to determine population size at one site ; 2 . exploration of new cave sites for presence of the fish ; 3 . exploration of new passages in known cave sites using scuba ; 4 . downloading data from a logger that was placed at one site 2 years ago .
hendrickson , d . a . , krejca , j . k . and martinez , j . m . r . ( 2001 ) mexican blindcats genus prietella ( siluriformes : ictaluridae ) : an overview of recent explorations . environmental biology of fishes , 62 : 315 - 337 .
hendrickson , d . a . and j . k . krejca . 1997 . notes on biogeography , ecology and behavior of mexican blind catfish , genus prietella ( ictaluridae ) . selected abstracts from the 1997 national speleological society convention in sullivan , missouri . journal of cave and karst studies , dec 1997 , 59 : 4 , p 166 .
i propose to employ a subcutaneous dye marking technique on populations of these fish in mexico in order to learn about the biology of these fish . data that can be gathered from mark - release - recapture studies such as what i propose include population size , growth rate , and longevity . also by repeatedly visiting sites where prietella is known from , data concerning their habitat , food sources and behavior will certainly be noted , and potentially observations of reproduction can be made .
in order to properly manage species that are at risk , some basic facts must be known about the organisms biology . things like longevity , fecundity , growth rates , migration , population sizes , feeding and reproduction should be understood . with prietella , none of this is known ( hendrickson and krejca 1997 ) . there are , however , techniques out there to learn about fish biology . salmon , for example , have been studied because of drastically declining numbers due to human impacts ( maxwell 1995 ) . marking techniques that were adapted for salmon , such as subcutaneous dye injection ( biophotonics 1995 ) , have been found to also work in these cave fish .
rare , blind catfish never before found in u . s . discovered in national park cave in texas | ut news | the university of texas at austin
rare , blind catfish never before found in u . s . discovered in national park cave in texas
these two mexican blindcats were discovered in an underwater cave near del rio , texas .
austin , texas — an extremely rare eyeless catfish species previously known to exist only in mexico has been discovered in texas .
the mexican blindcat , a species that grows to no more than 3 inches in length , is known to dwell only in areas supported by the edwards - trinity aquifer that underlies the rio grande basin in texas and coahuila . the new blindcat finding lends additional weight to a theory that water - filled caves below the rio grande may connect the texas and mexico portions of the aquifer .
“since the 1960s there have been rumors of sightings of blind , white catfishes in that area , but this is the first confirmation , ” hendrickson said . “i’ve seen more of these things than anybody , and these specimens look just like the ones from mexico . ”
jack johnson , a caver and national park service resource manager at amistad , first spotted some of the slow - moving , pinkish - white fish with no eyes in april 2015 . after several attempts to relocate the species , johnson and biologist peter sprouse of zara environmental llc led the team that found the fish again last month . mexican blindcats are a pale pink color because their blood can be seen through the translucent skin , and they dwell exclusively in groundwater .
“cave - dwelling animals are fascinating in that they have lost many of the characteristics we are familiar with in surface animals , such as eyes , pigmentation for camouflage , and speed , ” sprouse said . “they have found an ecological niche where none of those things are needed , and in there they have evolved extra - sensory abilities to succeed in total darkness . ”
the mexican blindcat was originally described in 1954 when found in wells and springs near melchor múzquiz in the northern mexican state of coahuila . it was subsequently listed as an endangered species by the mexican government , and as a foreign endangered species by the u . s . fish and wildlife service . hendrickson led efforts to locate additional blindcat sites in mexico and texas for years but only located them in mexico on previous expeditions .
“aquifer systems like the one that supports this rare fish are also the lifeblood of human populations and face threats from contamination and over - pumping of groundwater , ” johnson said . “the health of rare and endangered species like this fish at amistad can help indicate the overall health of the aquifer and water resources upon which many people depend . ”
the fish are not yet on public display . they will be maintained alive in a special facility designed to accommodate cave and aquifer species at the san antonio zoo’s department of conservation and research .
“the san antonio zoo has a series of labs specially designed to keep subterranean wildlife safe and healthy , ” said danté fenolio , vice president of conservation and research at the san antonio zoo . “the fact that the zoo can participate now and house these very special catfish demonstrates the zoo ' s commitment to the conservation of creatures that live in groundwater .
others involved in the discovery were andy gluesenkamp and ben hutchins of texas parks and wildlife , gary garrett and adam cohen of ut austin and jean krejca of zara environmental .
the finding brings the number of blind catfish species within the u . s . to three , all found only in texas . the two other species of blind catfish in texas , the toothless blindcat ( trogloglanis pattersoni ) and the widemouth blindcat ( satan eurystomus ) , live in part of the edwards aquifer complex , the deep edwards pool below the city of san antonio .
note : for reporters interested in capturing footage of the newly discovered texas mexican blindcat fish at the san antonio zoo , there will be media all day , monday , june 20 , 3903 n . saint marys street , san antonio , texas .
for more information , contact : christine sinatra , college of natural sciences , 512 - 471 - 4641 .
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: r . a . abell , d . m . olson , e . dinerstein , p . t . hurley , j . t . diggs , w . eichbaum , s . walters , w . wetengel , t . allnutt , c . j . loucks & p . hedao ( ed . ) freshwater ecoregions of north america : a conservation assessment , island press , washington , d . c .
williams , j . e . , j . johnson , d . a . hendrickson , s . contreras - balderas , j . d . williams , m . navarro - mendoza , d . e . mcallister & j . e . deacon . 1989 . fishes of north america endangered , threatened or of special concern : 1989 . fisheries 14 : 2–20 .
hendrickson , d . a . , krejca , j . k . & martinez , j . m . r . environmental biology of fishes ( 2001 ) 62 : 315 . urltoken
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contreras - balderas , s . & almada - villela , p . 1996 .
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this small , rare fish , which possesses no eyes , inhabits underground waters in mexico . the mexican blindcat has a pinkish - white , smooth , scaleless body with four pairs of long , whisker - like barbels around the mouth ( 2 ) ( 3 ) ( 4 ) . the adipose fin on the back is joined to the caudal , or tail , fin ( 2 ) . well - developed pores on the head ( 2 ) , linked by canals , form the lateral - line , a sense organ used to detect movement and vibration in the surrounding water .
like many organisms that inhabit caves the mexican blindcat possesses no eyes , which is compensated by the development of other senses ( 5 ) . studies have shown that the mexican blindcat has acute hearing and can rapidly perceive the odour or taste of non - moving food , such as mosquito larvae ( 6 ) . aggressive encounters between mexican blindcats have been observed , during which they bite at one another and then lock jaws , often remaining in mouth to mouth contact for many hours . all of the aggressive individuals appeared to be males ( 6 ) ; however , the reason behind this hostile behaviour is not yet fully understood . mexican blindcats have also been seen resting motionless on the substrate , or drifting with currents . this behaviour would seem to leave this small fish extremely vulnerable to predation , and thus may reflect the lack of predators in their natural habitat ( 6 ) .
the mexican blindcat occurs in the state of coahuila , mexico ( 2 ) .
classified as endangered ( en ) on the iucn red list 2007 ( 1 ) .
the mexican blindcat is considered by the world conservation union ( iucn ) to be endangered , due to its restricted range and an inferred population decline ( 1 ) . the region in mexico the blindcat inhabits is facing rapid population growth , resulting in increased pressure on groundwater resources . interviews with local people indicate that the water tables have declined in recent decades , which reduces the amount of available habitat for the mexican blindcat . growing human populations also results in increased pollution , which could contaminate the groundwater ( 6 ) , further threatening the existence of this fish .
despite the threats it faces , the mexican blindcat may inhabit underground waters that are undiscovered or inaccessible to humans , and therefore the total number of individuals could potentially be large ( 6 ) . further research to determine the population size and conservation status of the mexican blindcat is required to inform future conservation actions to protect this peculiar species .
miller , r . r . , minckley , w . l . and norris , s . m . ( 2004 ) freshwater fishes of mexico . the university of chicago press , chicago .
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adipose fin a second dorsal fin consisting of a flap of fatty tissue , which lacks supporting rays . larvae stage in an animal’s lifecycle after it hatches from the egg . larvae are typically very different in appearance to adults ; they are able to feed and move around but usually are unable to reproduce . subterranean beneath the earth’s surface or underground .
wheeler , a . ( 1985 ) the world encylopedia of fishes . macdonald and co . ltd . , london .
nelson , j . s . ( 1994 ) fishes of the world . third edition . john wiley and sons inc . , new york .
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like many organisms that inhabit caves the mexican blindcat possesses no eyes , which is compensated by the development of other senses ( 5 ) . studies have shown that the mexican blindcat has acute hearing and can rapidly perceive the odour or taste of non - moving food , such as mosquito larvae ( 6 ) . aggressive encounters between mexican blindcats have been observed , during which they bite at one another and then lock jaws , often remaining in mouth to mouth contact for many hours . all of the aggressive individuals appeared to be males ( 6 ) ; however , the reason behind this hostile behaviour is not yet fully understood . mexican blindcats have also been seen resting motionless on the substrate , or drifting with currents . this behaviour would seem to leave this small fish extremely vulnerable to predation , and thus may reflect the lack of predators in their natural habitat ( 6 ) .
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nelson , joseph s . , edwin j . crossman , h . espinosa - pérez , l . t . findley , c . r . gilbert , et al . , eds .
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pdf version of the powerpoint presentation that was presented at the 2017 meeting of the texas academy of science at mary hardin baylor university ( 4 . 612mb )
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this small , rare fish , which possesses no eyes , inhabits underground waters in mexico . the mexican blindcat has a pinkish - white , smooth , scaleless body with four pairs of long , whisker - like barbels around the mouth ( 2 ) ( 3 ) ( 4 ) . the adipose fin on the back is joined to the caudal , or tail , fin ( 2 ) . well - developed pores on the head ( 2 ) , linked by canals , form the lateral - line , a sense organ used to detect movement and vibration in the surrounding water .
occurs in wells . threatened by groundwater pollution and overfishing ( ref . 10172 ) .
central america : wells near the sierra de santa rosa in coahuila , mexico .
the mexican blindcat occurs in the state of coahuila , mexico ( 2 ) .
paratype : carranza , j . 1954 . ciencia , revista hispano - americana de ciencias puras y aplicadas . 14 ( 7 - 8 ) : 132 , 1 .
classified as endangered ( en ) on the iucn red list 2007 ( 1 ) .
the mexican blindcat is considered by the world conservation union ( iucn ) to be endangered , due to its restricted range and an inferred population decline ( 1 ) . the region in mexico the blindcat inhabits is facing rapid population growth , resulting in increased pressure on groundwater resources . interviews with local people indicate that the water tables have declined in recent decades , which reduces the amount of available habitat for the mexican blindcat . growing human populations also results in increased pollution , which could contaminate the groundwater ( 6 ) , further threatening the existence of this fish .
despite the threats it faces , the mexican blindcat may inhabit underground waters that are undiscovered or inaccessible to humans , and therefore the total number of individuals could potentially be large ( 6 ) . further research to determine the population size and conservation status of the mexican blindcat is required to inform future conservation actions to protect this peculiar species .
this fish is pinkish white in color and has no eyes . it grows up to 9 . 2 centimetres ( 3 . 6 in ) in length . it lives only in
borowsky , r . 1996 . the sierra de el abra of northeastern méxico : blind fish in the world’s largest cave system . trop . fish hobb . 46 : 178–188 .
carillo - bravo , j . 1971 . la plataforma valles - san luis potosf . bol . asoc . mex . geól . petr . 23 : 1–113 .
carranza , j . 1954 . description del primer bagre anoftalmo y depigmentado encontrado en aguas mexicanas . ciéncia ( méxico ) 14 : 129–136 .
darnell , r . m . 1962 . fishes of the rio tamesí and related coastal lagoons in east - central méxico . publ . inst . mar . sci . univ . texas ( 8 ) : 299–365 .
exley , s . 1979 . nacimientos ! diving the big springs of the sierra madre . ass . mex . cave stud . bull . 10 : 23–31 .
: w . back , j . s . rosenshein & p . r . seaber ( ed . ) hydrogeology ( volume 0–2 ) , geological society of america , boulder .
longley , g . 1981 . the edwards aquifer : earth’s most diverse groundwater ecosystem ? int . j . speleol . 11 : 123–128 .
eigenmann , with a phyloge - netic analysis of the ictalurid catfishes . misc . publ . mus . zool . univ . mich . ( 163 ) : 1–83 .
minckley , w . l . 1969 . environments of the bolsön of cuatro ciénegas , coahuila , méxico . science series , university of texas , el paso , texas ( 2 ) : 1–65 .
nelson , j . e . 1994 . fishes of the world . john wiley and sons , new york . 600 pp .
prentice , j . a . & p . thomas . 1987 . successful spawning of orange - mouth corvina following injection with des - glylo , [ d - ala6 ] - luteinizing hormone - releasing hormone ( 1–9 ) ethylamide and pimozide . prog . fish - cult . 49 : 66–69 .
reddell , j . r . 1981 . a review of the cavernicole fauna of méxico , guatemala , and belize . bull . tex . mem . mus . ( 27 ) : 1–327 .
secretaría de desarrollo social . 1994 . norma oficial mexicana nom - 059 - ecol - 1994 , que determina las especies y sube - species de flora y fauna silvestres y acuâticas en peligro de extinciön , amenazadas , raras y sujetas a protecciön especial , y que establece especificaciones para su protecciön . diario oficial de la federation , méxico 488 ( 10 ) : 2–60 .
smith , a . r . & g . veni , 1994 . karst regions of texas . pp . 7–12 .
: r . a . abell , d . m . olson , e . dinerstein , p . t . hurley , j . t . diggs , w . eichbaum , s . walters , w . wetengel , t . allnutt , c . j . loucks & p . hedao ( ed . ) freshwater ecoregions of north america : a conservation assessment , island press , washington , d . c .
( siluriformes : ictaluridae ) : an overview of recent explorations . in : romero a . ( eds ) the biology of hypogean fishes . developments in environmental biology of fishes , vol 21 . springer , dordrecht
1 . subcutaneous marking , release , then recapture on return visits . already we have preliminary data , as the marking began in 1998 . this gives population size , longevity .
2 . measurement of fish on capture and recapture . this gives growth rate .
4 . notes on behavior , relative proportion of body sizes . this gives reproduction and behavior data .
5 . measurement of water parameters ( temperature , at minimum , potentially ph , dissolved oxygen , total dissolved solids , salinity ) . this gives habitat data .
biophotonics news . 1995 . fisheries keep tabs on fly with photonic tags . biophotonics international . sept / oct 1995 , p 24 .
carranza , 1 . 1954 . descripción del primer bagre anoftalmo y depigmentado encontrado en aguas mexicanas . ciéncia , méxico 14 ( 7 - 8 ) : 129 - 136 .
contreras - balderas , s . and m . l . lozano - vilano . 1994 . water , endangered fishes , and development perspectives in arid lands of mexico . conserv . bid . 8 ( 2 ) : 379 - 387 .
iucn . 1996 . the 1996 iucn ( international union for the protection of nature , or world conservation union ) red list of threatened animals . iucn , gland .
maxwell , jessica . 1995 . swimming with salmon . natural history . sept 1995 , p 29 - 38 .
the mexican blindcat is a small catfish , achieving a length of up to 0 . 5 in ( 1 . 2 cm ) . its eyes are greatly reduced and non - functional , and its skin lacks pigmentation .
the mexican blindcat does not have functional eyes , and perceives its environment through its tactile barbels and probably also by sensing electrical fields . the male digs a shallow nest , where the female lays eggs , which are fertilized externally by milt ( sperm ) excreted by the male . the developing eggs in the nest are guarded until they hatch . the mexican blindcat has been maintained in captivity , but it has not been induced to breed .
the mexican blindcat occurs in dark , underground , freshwater pools and wells in tropical areas . this unusual aquatic habitat is known as
hypogeous ,
or underground habitat . the underground habitat is periodically subject to rapid changes in water volume , due to flows associated with surface rains and underground streams passing through bedrock fractures .
the mexican blindcat was first discovered in underground cave - pools and wells in central coahuila state , mexico . recent discoveries of populations of congeneric ( same genus ) blindcats in northern and eastern mexico have expanded the range of this fish . initial taxonomic research considers that these populations represent at least two different species .
some populations of the mexican blindcat have been severely affected by habitat damage caused by pollution by nutrients and pesticides , and perhaps by excessive collecting .
recent fieldwork in northern mexico has found additional populations of the mexican blindcat , so the species may not be as endangered as once thought . however , all of its known habitats are vulnerable to pollution and disturbance . the habitats of the mexican blindcat are not protected .
borowsky , r . 1996 .
the sierra de el abra of northeastern mexico : blind fish in the world ' s largest cave system .
tropical fish hobbyist 44 ( 7 ) : 178 - 188
parzefall , j . 1993 .
behavioural ecology of cave - dwelling fishes .
in behaviour of teleost fishes , edited by t . j . pitcher . chapman & hall , london . pp . 573 - 606 .
mexican blindcat .
beacham ' s guide to the endangered species of north america . . encyclopedia . com . ( july 7 , 2018 ) . urltoken
mexican blindcat .
beacham ' s guide to the endangered species of north america . . retrieved july 07 , 2018 from urltoken urltoken
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minckley , wl , dean a hendrickson , and ce bond . 1986 . “ geography of western north american freshwater fishes : description and relations to intracontinental tectonism . ” zoogeography of western north american freshwater fishes , edited by ch hocutt and eo wiley , 519 - 613 . new york , ny : john wiley and sons , 519 - 613 .
salvador contreras balderas , universidad autónoma de nuevo león . additional text modified from abell et al . ( 2000 ) .
largely defined by the watersheds of the río sabinas and río salado , this ecoregion includes central and eastern coahuila , northern nuevo león , and a small portion of tamaulipas .
río salado is a tributary of the rio grande ( río bravo ) , which flows into the gulf of mexico .
rivers in the ecoregion include the río salado , río sabinas , northern río san juan , and southern río salado de nadadores . the cuatro ciénegas spring complex drains eastward into the headwaters of the río salado .
the río salado originates in low mountains of the sierra madre oriental , and flows in a southeasterly direction through plains .
the climate of this ecoregion is primarily arid and semiarid ( köppen 1936 ) . the chihuahuan desert in the western part of the ecoregion is characterized by dry summers and occasional winter rains ( davis et al . 1997 ) . the mean annual temperature ranges between 14 - 23 ºc , and mean annual precipitation ranges between 200 - 675 mm .
the ecoregion is characterized by clear headwater streams , mostly piedmont , and slow plains in the middle to lower reaches . this basin has two ecologically very distinctive tributaries : the northern río san juan , with strictly freshwater , hilly headwaters and hard bottoms ; and the southern río salado de nadadores along the plains , which is highly saline for the most part . the mainstem of the río salado has high salt content , is muddy , and is low gradient .
the ecoregion is characterized by the chihuahua desert in the west , with pockets of sierra madre oriental pine - oak forests . tamaulipan mezquital is the dominant vegetation type in the east , with small areas of tamaulipan matorral . mesquite - grassland is characteristic within tamaulipan mezquital . creosote bush ( larrea tridentata ) is dominant in the chihuahuan desert ( world wildlife fund 2001 ) .
the fish assemblage in the lower course is notorious due to its big river forms and the euryhaline character of most species . these species do not invade the upper course – they do not go above the lower rio grande valley . some of the euryhaline species include the longnose gar ( lepisosteus osseus ) and spotted gar ( l . oculatus ) ( lepisosteidae ) ; mosquitofish ( gambusia affinis ) , tex - mex gambusia ( g . speciosa ) , and robust gambusia ( g . marshi ) ( poeciliidae ) ; and rio grande cichlid ( herichthys cyanoguttatus ) ( cichlidae ) .
the río salado ecoregion possesses no known endemic mussels , crayfish , or aquatic herpetofauna .
usually speciation has developed in allopatry , mostly through a combination of barriers and dispersals . the divergence may be exemplified by a number of cases . the series of the cyprinid cyprinella is represented by forms in different major tributaries of the río bravo / rio grande . for example , the mexican red shiner ( cyprinella rutila ) occurs in the río salado .
ecoregion delineations were based on qualitative similarity / dissimilarity assessments of major basins , using the standard administrative hydrographical regions of the mexican federal government .