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Goodeider

Tapatia occidentalis

Allodontichthys
       hubbsi
       polylepis
       tamazulae
       zonistius
Alloophorus
       robustus
Allotoca
       catarinae
       diazi
       dugesii
       goslinei
       maculata
       meeki
       regalis
       Aquiles Serdan
       zacapuensis
Ameca
       splendens
Ataeniobius
       toweri
Chapalichthys
       encaustus
       pardalis
       peraticus
Characodon
       audax
       garmani
       lateralis
       Los Berros
       Guadalupe Aguilera
       Abraham Gonzales
       Amado Nervo
       Los Pinos
       27. de Noviembre
Girardinichthys
       multiradiatus
       turneri
       viviparus
Goodea
       atripinnis
Ilyodon
       amecae
       comala
       cortesae
       furcidens
       whitei-lennoni
       xantusi
Skiffia
       bilineata
       francesae
       lermae
       multipunctata
       spec. Zacapu
Xenoophorus
       captivus
       spec. Illescas
Xenotaenia
       resolanae
Xenotoca
       eiseni
       melanosoma
       spec. San Marcos
       variata
Zoogoneticus
       purhepechus
       quitzeoensis
       tequila

Universitet Morelia

© All rights reserved
 2000 - 2011
Guenter Ellenberg

 

All oversettelse fra tysk til “skandinavisk” er gjort av Jan Arne Stenl√łkk, Stavanger, Norge

Goodeider

N√•r man snakker om levendef√łdende fisk, tenker de fleste p√• guppy, platy og sverddragere, da de nok er de mest kjente representantene for levendef√łdende tannkarper (Poeciliidae). Det er likevel nesten ingen som kjenner til familien Goodeidae og underklassen Goodeinae.

Derfor er f√łrste prioritet for disse sidene √• anbefale deg disse virkelig interessante fiskene.

Goodeidene, som er endemiske I h√łylandsomr√•dene I det s√łrvestre Mexico, er sm√• fisk, men fra et biologisk st√•sted er det en s√¶rdeles interessant familie I ordnen Cyprinodontiformes.

I tidligere tider var familien med goodeider antatt √• inneholde et sted mellom 25-40 arter, fordelt p√• 15 slekter med levendef√łdende tannkarper. De atskilte seg fra Poecilidene blant annet gjennom et innhakk p√• analfinnen hos hannene.
 

I arbeidet til PARENTI (1981), som tar for seg klassifikasjonen til Cyprinodontiformes, egg-leggende fiskeslekter fra Death Valley og √łstlige deler av Nevada, USA, ble disse lagt til familien Goodeidae: Empetrichthys og Crenichthys. I tillegg til √• v√¶re egg-leggende, er det ogs√• ande kjennetegn som skiller disse to slektene fra andre goodeider. For eksempel mangel p√• bukfinner. PARENTI deler Goodeidae I ti underfamilier:: Empetrichthyina med slektene Empetrichthys og Crenichthys, og Goodeinae med resten av slektene. De egglggende slektene i underfamilien Empetrichthyinae blir ikke omtalt videre her. Der er dermed bare underfamilien Goodeinae som diskuteres videre, og som omtales som goodeider.

 

530-05 Verbreitungsgebiet_Goodeiden_Mexiko-Karte_4sek
De sorte områdene viser utbredelsen av goodeider I Mexico

 

Goodeider fines utelukkende i et begrenset omr√•de i det sentrale h√łylandsomr√•det i Mexico. Her holder de til, avhengig av slekt, i ulike biotoper som dammer, innsj√łer, sakte- og hurtigstr√łmmende bekker og elver. Som alle andre steder i dyreriket er det milj√łet og f√łden som gir grunnlaget for fiskens utseende. Evolusjonen av goodeider er et imponerende eksempel p√• tilpassningen til de √łkologiske nisjene. Derfor kan kj√łttetende fisk med koniske tenner og kort tramsystem finnes, s√• vel som plantespisende fisk med langt tarmsystem og altetende (omnivore) fisk med ulike typer tenner.

Levestedene gir også endring av fiskenes anatomi.

Blant goodeider finnes, som for de fleste familier av beinfisk, et fullt sett med √łkologiske former: overflatearter, fisk som foretrekker √•pne vannmasser, og andre som holder til p√• bunnen det meste av tiden blant beskyttelsen av planter. Derfor har noen hurtigsv√łmmende arter fra raskt str√łmmende elver (som for eksempel Ilyodon) en str√łmlinjeformet kropp. Fisk fra dammer og innsj√łer (som Xenotoca, Skiffia, Zoogoneticus) har en bred ryggside. Bunnlevende arter har et utseende og levevis som minner om cichlider og abborfisker. Et godt eksempel er Allophorus robustus.

I naturen er leveomr√•dene under vannet bygget opp i hovedsak av kalkstein, og goodeidene er derfor tilpasset hard tog kalkholdig vann med n√łytalt eller temmelig alkalisk pH-verdier. Utbredelsen er I Rio Lima med tilst√łtende vassdrag I det sentrale Mexico. H√łye, vulkanske fjellrygger omkranser flere plat√•er. Det er en stor grad av variasjon I temperaturen gjennom √•ret, men ogs√• gjennom dagen. Lite nedb√łr er typisk for dette omr√•det. I h√łyereliggende omr√•der kan det ogs√• bli frost og et tynt isdekke p√• vannet kan forekomme tidlig p√• morgenen, mens solen vil steke rundt middagstid. Dermed gir dette en stor temperaturforskjell.

Fossiler tyder p√• at goodeidene begynte √• utvikle i sine typiske biotoper i det sentrale h√łylandsomr√•det I Mexico for mellom 20 og 25 millioner √•r tilbake.

F√łrste gang en levendef√łdende goodeide omtales, er fra √•ret 1772, og det var trolig arten Girardinichthys viviparus.
De fleste goodeider vokser opp relativt hurtig og n√•r seksuell moden alder f√łr de er seks m√•neder gamle. Men fiskene kan bli temmelig gamle for √• v√¶re akvariefisk: Mens mindre arter har en forventet levetid p√• tre √•r, og middles store fire √•r, kan st√łrre fisk bli sju eller ti √•r gamle.

Vitenskapelig ble goodeidene beskrevet temmelig sent, og de var lenge ukjent blant akvarister. F√łr beskrivelsen av Ameca splendens av MILLER & FITZSIMMONS (1971) var de fleste slektene praktisk talt ukjente. Siden Ameca var sv√¶rt ulik andre levendef√łdende, ble det stor interesse for denne fisken far begge sider av Atlanterhavet. Derfor ble denne tidligere ukjente goodeiden rakst tilgjengelig innen f√• √•r.

I dag er det fortsatt interesse for goodeider, men den entusiastiske aktiviteten fra midten av 70-tallet og 80+-tallet er blitt mer dempet. Mellom 1939 og 1971 ble goodeider vitenskapelig unders√łkt, men familien ble ikke taxonomisk analysert. Blant forskere var det liten interesse for goodeider fram til 1970-tallet.

Dette er heldigvis endret I dag, og vi kan snake o men godt unders√łkt familie av fisker, selv om utbredelsen og slektskapet til noen slekter fortsatt er kontroversielt. P√• grunn av den store variasjonen innen en art (og nylig oppdagede arter?) er det trolig n√łdvendig med videre unders√łkelser.

Det må også tas med at utviklingen av artene ikke virker ferdig. Det er trolig grunnen til den store variasjonen innen artene. Variasjonen er enkelte ganger så utpreget at flere forfattere har ulike syn på slektsforholdene. Dette gjelder for eksempel for Allotoca diazi, Chapalichthys pardalis, Goodea atripinnis og Ilyodon whitei. MDet er helt klart at det kommer til å bli endringer på arts- og slektsnivå i framtiden.

Goodeider skiller seg fra poeciliidene ved deres forplantningsmetode, som hos begge er indre forplantning. Men goodeidene har intet kompleks forplantningsorgan (gonopodium), men har bare en liten, fleksibel del av framre analfinne separert ved et innhakk (andropodium). Dette, sammen med n√¶ringstilf√łrselen til fosterne ved et trophotaenia, er de viktigste karaktertrekkene hos goodeidene.

Hunnene hos goodeidene kan ikke oppbevare spermceller fra hannen, og det m√• derfor v√¶re en ny parring f√łr hver graviditet
 

 

08 Gonopodium        ¬©07 Andropodium

Under, forskjellen mellom et gonopodium (venstre bilde) og et andropodium er synlig.
Foto: Jan-Eric Larsson

 

 

06 Analflosse_eines_Goodeiden-Männchens
Analfinnen hos en hann av en goodeide

A = andropodium
F = finne
I = Indre bevegelsesmekanisme for analfinnen.

Foto fra Meyer, Wischnath, Förster

 

Med unntak av slekten Ataeniobius, har alle goodeider utviklet en unik form foreldrepleie f√łr yngelen klekker, nemlig n√¶ringstilf√łrsel til ungene mens de enn√• ligger i morens buk. Goodeidene er levendef√łdende fisker, som I motsetning til platy eller guppy, ikke er ovovivipare, men vivipare. Det betyr at utviklingen av fosteret skjer for st√łrste delen i buken og utenfor egget. Ulikt for eksempel guppy, der fosteret f√•r n√¶ring av plommesekken (lecithotrofi), har goodeidene utviklet matrotrofi og ungene f√•r n√¶ringen direkte fra moren.

 

09 Goodeidenjunges_im_Mutterleib

 

11 Trophotaenien_allgemein_mit_Erklarung
Trofotaeniae
L = anal label
N = næringsbånd

 

Etter eggene har forlatt eggstokkene, utvikler fosteret utvekster foran analfinnen, som gj√łr det i stand til √• absorbere n√¶ring. Slike strukturer kalles trophotaeniae (trophe = n√¶ring, taenia = b√•nd). Via disse forgreningene mellom hunnen og fosteret, som ikke er helt fastvokst til eggstokkenes vev, f√•r fiskeungen ulike n√¶ringssubstanser fra moren. Etter f√łdselen er trophotaeniaet fortsatt synlig, men det forsvinner etter et par dager.

 

Zoogoneticus tequila Trophotaenien
Trofotaeniae av Zoogoneticus tequila

 

 

Xenotoca eiseni 21 Seite 77 196
Nyf√łdt Xeotoca eiseni med tydelig synlig trofotaeniae.
Bilde fra: Aqualog Verlag, Tittel: Alle Lebendgebärenden,
Foto: Uwe Werner

 

 

Xenotoca eiseni 20
F√łdsel av Xenotoca eiseni med synlig trofotaeniae.
Bilde fra: Weltbild Verlag, Tittel: Suesswasserfische der Welt,
Foto: Richter

 

 

Xenotoca eiseni 05 Seite77 193
F√łdsel av Xenotoca eiseni med trofotaeniae.
Bilde fra: Aqualog Verlag, Tittel: Alle Lebendgebärenden,
Foto: Uwe Werner

 

P√• grunn av √łkt industialisering og intensivt jordbruk i Mexico, er det mange omr√•der i landet som har stort forbruk av vann. Derfor blir mange biotoper truet, og er i fare for √• bli √łdelagt, eller er ikke lenger eksisterende. Selv om mange goodeider for en tid kan overleve i forurenset vann, er det ikke tilstrekkelig for √• holde populasjonen ved like.

Noe arter (som Ameca splendens) forekommer bare i en spesiell elv eller innsj√ł (endemisk). I slike tilfeller er en st√łrre milj√łendring eller menneskelig p√•virkning noe som raskt kan f√łre til utd√łing av hele arten eller slekten.

Listen under gir grovt overslag over sitasjonen for de enkelte artene:

 

Allodontichthys hubbsi

truet siden år 2000

stabil siden år 2000

Allodontichthys polylepis

utd√łdd?

Ingen funn etter år 2000

Allodontichthys tamazulae

sårbar seit 2000

stabil siden år 2000

Allodontichthys zonistius

Sårbar siden år 2000

stabil siden år 2000

Alloophorus robustus

Sårbar siden år 2000

Noe tilbakegang siden år 2000

Allotoca catarinae

Sårbar siden år 2000

stabil siden år 2000

Allotoca diazi
(Syn. Neoophorus diazi)

utsatt for risiko

Kun restpopulasjon igjen

Allotoca dugesii

truet siden år 2000

i tilbakegang siden år 2004

Allotoca goslinei

utd√łdd?

Ingen funn etter år 2004

Allotoca goslinei

utd√łdd?

Ingen funn etter år 2004

Allotoca maculata

utsatt for risiko

Kun restpopulasjon igjen

Allotoca meeki

Svert utsatt for risiko

Kun restpopulasjon igjen

Allotoca zacapuensis

Svært utsatt for risiko

stabil, men meget sjelden

Ameca splendens

utsatt for risiko

To nye funn av populasjoner

Ataeniobius toweri

utsatt for risiko

stabil siden år 2000

Chapalichthys encaustus

sårbar

I tilbakegang i Chapala-sj√łen

Chapalichthys pardalis
(Syn. Chapalichthys peraticus)

truet siden år 2000

stabil siden år 2000

Characodon audax

utsatt for risiko

Ny populasjon er funnet

Characodon garmani

Utd√łdd siste 100 √•r

Ingen funn siste 100 år

Characodon lateralis

utsatt for risiko

---

Girardinichthys multiradiatus

truet

stabil siden år 2000

Girardinichthys viviparus

utsatt for risiko

Kun restpopulasjon igjen

Goodea atripinnis
(Syn. G. gracilis, G. luitpoldi)

liten risiko

i tilbakegang siden år 2000

Hubbsina turneri
(Syn. Girardinichthys ireneae)

utsatt for risiko

Noe tilbakegang siden år 2000

Ilyodon cortesae

truet

i tilbakegang siden år 2000

Ilyodon furcidens
(Syn. I. xantusi, I. amecae

liten risiko?

I tilbakegang i Ayuquila-floden

Ilyodon whitei
(Syn. I. lennoni)

Sårbat siden år 2000

Noe i tilbakegang siden år 2000

Neoophorus regalis
(Syn. Allotoca regalis)

utsatt for risiko

I tilbakegang og svært sjelden

Skiffia bilineata
(Syn. Neotoca bilineata)

utsatt for risiko

stabil siden år 2000

Skiffia francesae

utd√łdd

Akvariestammer finnes

Skiffia lermae

truet siden år 2000

Noe i tilbakegang siden år 2000

Skiffia multipunctata

truet siden år 2000

Noe i tilbakegang siden år 2000

Xenoophorus captivus

truet siden år 2000

i tilbakegang siden år 2000

Xenoophorus resolanae

sårbar

stabil siden år 2000

Xenotoca eiseni

utsatt for risiko

utsatt for risiko

Xenotoca melanosoma

truet

stabil siden år 2000

Xenotoca variata

liten risiko

stabil

Zoogoneticus purhepechus

truet siden år 2000

stabil siden år 2000

Zoogoneticus quitzeoensis

truet siden år 2000

Noe i tilbakegang siden år 2000

Zoogoneticus tequila

utsatt for risiko

Bare en liten populasjon

Totalt: 39 Arten – 4 utd√łdd (2 usikre); 22 er utsatt for risiko; 3 truet; 7 s√•rbar; 3 liten risiko (1 uviss).

 

Goodeider er som regel enkle √• holde og √• avle, men det fines unntak. Noen arter, som den sv√¶rt attraktive Girardinichthys viviparus trenger mye tilsyn, mens Alloophorus robustus er kraftig og robust √• holde. Det er derfor ikke bestandig slike fisker passer √•  holde i et selskapsakvarium med mange andre arter.

N√•r goodeider holdes i et akvarium, m√• enkelte momenter vurderes: for mindre og fredlige arter er ca 60 liter tilstrekkelig dersom det regnes 5 liter vann pr fisk. Fisk holdes lettere dersom de har mer plass i akvariet, noe som ogs√• gjelder for goodeider s√• vel som for alle andre akvariefisk. Det er imidlertid ikke n√łdvendig √• holde bare en fiskeart i hvert akvarium. Mange slekter kan ogs√• holdes i et selskapsakvarium uten problemer. Detaljer rundt dette finnes under beskrivelsen for den enkelte art. Det b√łr alltid v√¶re beskyttelse og gjemmesteder med planter i akvariet.

N√•r det gjelder temperaturen i vannet, m√• en skille mellom de artene som klarer seg uten oppvarming med bare 17 – 22 ¬įC, og arter som liker varmere vann (som Ataeniobius toweri, som trenger opp til 28 ¬įC). Igjen er detaljer om dette gitt under beskrivelsen for den enkelte art.

Fordi goodeider som regel lever under forhold med dempet belysning og plantedekke p√• overflaten, b√łr det ikke v√¶re for sterk belysning over akvariet.

Dersom en holder arter fra stille vassdrag, b√łr det ikke v√¶re for sterk str√łm fra akvariefilteret. Detaljer er beskrevet for de enkelte artene.

Vannparameterne er ellers underordnet. Vannet b√łr v√¶re hard tog ha en pH-verdi p√• n√łytral (7) eller alkalisk (opp til 9). Selv holder jeg goodeider i vann med pH over 8, og byter ukentlig 25-30 % av vannet uten ytterligere vannbehandling.

Utforingen av goodeider er uproblematisk, men det b√łr v√¶re en variert meny. I naturen er noen arter spesialisert med hensyn p√• f√łde (som levendefor eller plantekost), men i akvariet er de som regel altetende.

Skoldet spinat (sammen med alger) er en god basis for plantekost. Algene i akvariet b√łr ikke fjernes fra alle omr√•der, da goodeidene setter pris p√• slike i sine naturlige omgivelser. Artemia, vannlopper, mygglarver (sorte, hvite, r√łde) etc har vist seg √• v√¶re et godt levende for. Generelt b√łr en v√¶re forsiktig med √• gi for mange r√łde mygglarver. En diett med et for h√łyt innhold av proteiner kan ogs√• trolig lede til sterilitet. Det er i alle fall rapportert fra enkelte kjente oppdrettere. Kun fortsatte eksperimenter og erfaring vil gi sikkerhet rundt dette.

N√•r en holder fisk i slekten Alloophorus, er det vanskelig √• unng√• √• gi levende fisk som f√łde for √• f√• sunne dyr. Det er trolig ogs√• essensielt for √• oppn√• vellykket oppdrett. Detaljer om utforingen er gitt under artsbeskrivelsene.

For fiskene er det bra √• unng√• √• gi mat en dag hver uke. N√•r akvarieeieren drar p√• ferie klarer goodeidene seg uten mat i noen dager, og voksen fisk kan g√• uten f√łde i en uke uten problemer. I l√łpet av denne tiden lever fiskene av alger i akvariet. Unger b√łr f√• f√łde daglig de f√łrste ukene etter f√łdselen, da det ellers kan ha en negativ effekt p√• utviklingen, noe som ikke kan kompenseres senere i livet.

Oppdrett av goodeider varierer i vanskelighetsgrad fra enkelt til sv√¶rt vanskelig, avhengig av slekten. Detaljer er gitt under artsbeskrivelsene. Akvarister som ikke er kjent med goodeider b√łr merke seg en forskjell fra andre levendef√łdende tannkarper. Mange goodeider har en hvilepause under vinteren, og under denne tiden er det lange intervaller uten at de kaster unger.

Dersom forholdene i akvariet erg ode, er goodeidene lite mottakelige for sykdommer sammenliknet med andre fiskeslag. Men holdes de for varmt kan det gi problemer, spesielt med fisketuberkulose. S√¶rlig er slekten Goodea og Zoogeneticus utsatt for dette. Sykdommen er synlig som byller p√• huden. Mot slutten d√łr de infiserte fiskene. Hyppige og regelmessige vannbytter og lavere temperaturen hjelper ofte i slike tilfeller, og detaljer er gitt under artsbeskrivelsene.

Klassifikasjonen av goodeidene er temmelig kompleks, og enkelte ganger kontroversiell. Et viktig kjennetegn er trophotaeniaet til ungene, mens andre kjennetegn er tenner og kromosomstruktur.

Det er trolig at slekten Goodea blir begrenset til bare artene Goodea atripinnis (Goodea atripinnis martini og Goodea atripinnis luitpoldi ble antatt å være ulike arter). Også slekten Ataeniobius (med bare en enkelt art: Ataeniobius toweri) kan bli klassifisert med Goodea. I så fall blir Ataeniobius toweri kalt for Goodea toweri.

 

Slekt

Utbredelse

Levested

Allodontichthys

Colima, Jalisco

Hurtigstr√łmmende bekker og elver (under steiner)

Alloophorus

Michoac√°n

Innsj√łer, bekker og sumper

Allotoca

Jalisco, Guanajuato, Michoac√°n

Dammer og tjern

Ameca

Jalisco

Hovedvassdraget til Rio Ameca og Rio Teuchitlan

Ataeniobius

San Luis Potosi

Laguna La Media Luna

Chapalichthys

Jalisco, Michoac√°n

Vannreservoirer, dammer og innsj√łer

Characodon

Durango, SW-Coahuila

bekker

Girardinichthys

Mexiko D.F., Michoac√°n

Bekker og st√łrre elver

Goodea

Aguascalientes, Guanajuato, Jalisco, Michoac√°n, Nayarit, Queretaro, Zacatecas

alle habitater med stillest√•ende eller str√łmmende vann

Ilyodon

Colima, Guerrero, Jalisco, Mexiko D.F., Michoac√°n, Morelos, Nayarit, Puebla,

Hurtig str√łmmende bekker og elver

Skiffia

Guanajuato, Jalisco, Michoac√°n,

Tjern, dammer og innsj√łer.

Xenoophorus

San Luis Potosi

Bekker og elver

Xenotaenia

Colima, Jalisco

Bekker og elver

Xenotoca

Guanajuato, Jalisco, Michoac√°n, Nayarit

Elver, innsj√łer, vannreservoarer og innsj√łer

Zoogoneticus

Guanajuato, Jalisco, Michoac√°n

Kanaler og innsj√łer

 

 

Litteratur fra Kees de Jong, Nederland
508-Kees de Jong

 

Goodeidaen:

(1990) : Hooglandkarpers II. Poecilia Nieuws  (3): 51-52

(1990) : Hooglandkarpers II. Poecilia Nieuws  (4): 61-63

(1990) : Hooglandkarpers. Poecilia Nieuws  (2): 13-14

(1990) : Brood records. Livebearers (111): 36-38

(1991) : Brood records. Livebearers (117): 42-44

(1991) : Brood records. Livebearers (115): 34-36

(1992) : Brood records. Livebearers (121): 33-36

(1992) : Brood records. Livebearers (126): 41-44

(1992) : Brood records. Livebearers (123): 37-40

(1993) : Brood records. Livebearers (131): 24-28

(1993) : Brood records. Livebearers (129): 32-36

(1994) : Brood records. Livebearers (134): 27-31

(1995) : ALA brood records. Livebearers (139): 22-31

D. Bork (1990) : Goodeiden - wie sie zu uns kamen und wie sie zu beliebten Aquarienfischen wurden. ZAG Lebendgeb√§rende Zahnkarpfen  (3): 9-11

D.E.  Boruchowitz (2003) : Livebearing from A to Z. Tropical Fish Hobbyist  (May): 94-98

M. Brembach (1978) : Es geht auch ohne Gonopodium. DATZ  (8): 265-267

C. Br√ľning (1910) : Amerikanische Zahnkarpfen III. Characodontinae. Wochenschrift f√ľr Aquarien und Terrarienkunde (9): 117-118

C. Br√ľning (1910) : Amerikanische Zahnkarpfen I. Allgemeine √úbersicht. Wochenschrift f√ľr Aquarien und Terrarienkunde (4): 3-6

B.  Clarke (1983) : Goodeids I have known. Livebearers  (67): 9-10

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JOHN LYONS

University of Wisconsin Zoological Museum, Madison

From January 7-17, 2004, I participated in scientific fish surveys in springs, streams, and rivers over a broad area of central M√©xico.  This fieldwork had multiple objectives and focused on a variety of species, including catostomids (suckers of the genus Scartomyzon), cyprinids (minnows of the genus Aztecula,Algansea, Hybopsis, and Yuriria), lampreys (Lampetra geminis), and goodeids.  Here I summarize the observations made on goodeids.

Lago Mayor, Chapultepec Park, México, D.F.
I arrived in Mexico City late on 7 January, and the next morning Norman Mercado-Silva, from the University of Wisconsin-Madison, and Andr√©s Mart√≠nez-Aquino, from the Universidad Nacional Aut√≥noma de M√©xico (UNAM), M√©xico, D.F., and I sampled a small lake in Chapultepec Park in Mexico City for Girardinichthys viviparus.  This goodeid is endemic to the Valle de M√©xico, the endorheic (no natural outlet) basin where Mexico City is located.  Girardinichthys viviparus is critically endangered, and is currently known from only three areas, the lakes of Chapultepec Park, Lago de Xochimilco, located on the southern edge of Mexico City, and a small spring tributary to the R√≠o Tula in the adjacent state of Hidalgo, north of the Valle de M√©xico.

The Lago de Xochimilco and R√≠o Tula spring populations of G. viviparus are apparently small, whereas the size of the Chapultepec population is unknown.  Lago de Xochimilco is one of the last remnants of the extensive shallow natural lakes that once covered much of the Valle de M√©xico. The lake is heavily modified and polluted, with limited fish life.  However, over the last 15 years there have been increasing efforts to restore the environmental quality of this lake.  The R√≠o Tula spring population of G. viviparus is outside the native range of the species and appears to be from a relatively recent colonization.  In the late 1800s a canal was constructed between the Valle de M√©xico and the R√≠o Tula (which is part of the R√≠o P√°nuco basin flowing into the Gulf of Mexico) to drain the lakes in the Valle de M√©xico.  Girardinichthys viviparus presumably used this canal to reach the spring sometime within the last 100 years. The R√≠o Tula now carries large volumes of poorly treated sewage and industrial wastes and does not support fish life, so the spring population is effectively isolated from the Valle de M√©xico.

Chapultepec Park is a large and beautiful park in the heart of M√©xico City, somewhat reminiscent of Central Park in New York City.  It has a number of small “lakes” (=ponds), each a few hectares in size.  They all appear to be artificial, with steep, concrete lined sides and canals and pumps to control their water levels.  However, they may well be located at the sites of former natural ponds or wetlands.  The water quality in each is poor.  Their steep, slippery sides make fish sampling difficult.

We were able to sample fish from the largest lake, Lago Mayor, located across the street from the famous National Anthropological Museum (19 25’ 21.1” N; 99 11’ 2.7” W).  This lake has a boat rental area, and here the water is shallow enough to pull a seine (see photo).  We made two short seine hauls, covering about 50 m2 total, and captured well over 150 G. viviparus (see photo), plus about 100 Goodea atripinnis.  We also collected several individuals of G. viviparus in a trap made from a 1-liter soda bottle with a hole cut in the side and baited with bread.  This type of trap is commonly used by kids to capture goodeids from the Chapultepec Park lakes; many captured fish are kept as pets or eaten.  Most of the G. viviparus we caught had distended abdomens full of parasitic worms.

The population in Lago Mayor appears to be relatively large, despite the artificial habitat conditions, poor water quality, and heavy parasite burden. This is encouraging given the rarity of the species.  However, the Chapultepec population occupies a small isolated habitat and is hardly secure. It could be quickly decimated or even eliminated if, for example, the lakes were drained for repair.

La Mintzita springs, Michoac√°n
After we sampled Lago Mayor, we were joined by Guillermina Caba√Īas-Carranza from UNAM and Dr. Hank Bart and Mark Clements from Tulane University, New Orleans, and we began the expedition in earnest.  We left Mexico City that evening and headed west to Morelia.  We arrived there late on 9 January, after sampling two non-goodeid sites along the way.  On the 10th we met with Professor Martina Medina-Nava from the Universidad Michoacana de San N√≠colas de Hidalgo (UMSNH), Morelia, and three of her students.  Together, we first sampled the R√≠o San Marcos, Michoac√°n, in a small wooded canyon below the falls of Chiquimitio (19 47’ 56.4” N; 101 14’ 45.9” W) for the native catostomid Scartomyzon austrinus and the native lamprey Lampetrageminis. This stream was not really suitable goodeid habitat, being 5 m wide, 0.5-1,2 m deep with a cobble/gravel and boulder bottom and a very steep channel with fast currents.  However, in 120 m of electroshocking we did catch 5 specimens of the goodeid Goodea atripinnis, along with 18 L. geminis, 60 S. austrinus, and 7 Aztecula sallei (Cyprindae, native).  After a late lunch, we met briefly with Professor Omar Dom√≠nguez-Dom√≠nguez, who is in charge of the goodeid conservation and captive maintenance facility at UMSNH.  Then, as the afternoon waned, we visited the La Mintzita springs about 20 km southwest of Morelia (19 38’ 52.3” N; 101 16’ 13.0” W), one of the most important remaining goodeid habitats in central M√©xico.

La Mintzita is a marshy spring –fed lake (see photo) that drains into the R√≠o Grande de Morelia and hence into Lago Cuitzeo.  The R√≠o Grande de Morelia/Cuitzeo basin is endorheic, although its fauna indicates that it was once connected to the adjacent R√≠o Lerma basin.  Most of the R√≠o Grande de Morelia/Cuitzeo system has been greatly degraded, and La Mintzita is one of the last remaining high-quality sites in the basin.  A few hundred meters below the lake the outlet canal receives wastes from a large paper mill and no longer has the capability to support fish life, so La Mintzita is isolated from other fish populations in the basin.

We sampled the outlet canal just below the lake with a backpack electroshocker and the lake itself just above the outlet with a seine.  The canal was about 8-m wide and 0.5-1.0 m deep with a fast strong current and gravel bottom.  In 80 m of sampling we collected the following goodeids: 3 Alloophorus robustus, 30 Goodea atripinnis, about 100 Xenotoca variatia, 5 Skiffia lermae, and about 15 Zoogoneticus quitzeoensis (see photo).  We also caught 10 Poeciliopsis infans (Poeciliidae; native) and about 25 Xiphophorus helleri (an exotic Poeciliid), plus 10 Yuriria alta (Cyprinidae; native) and 10 Scartomyzon austrinus.  We then pulled the seine for about over about 300 m2 in the lake, which averaged about 1-m deep with a sand and clay bottom and clear water at 15-19 C temperature.  We captured 3 A. robustus, 5 G. atripinnis, 30 X. variata, about 100 S. lermae, 3 Z. quitzeoensis, plus at least 1000 P. infans, 5 X. helleri, and 30 Y. alta.  The S. lermae males were particularly beautifully colored, but unfortunately by the time we finished processing our samples it was too dark for photos.

Skiffia lermae is endangered and A. robustus and Z. quitzeoensis are uncommon, and La Mintzita is one of their last strongholds, whereas Goodea atripinnis and X. variata are widespread and common in central M√©xico.  La Mintzita remains in good condition, but its future is uncertain.  Settlement and use of the adjacent lands around the lake have increased in the last 10 years, as has runoff of domestic wastes into the lake.  More ominously, the city of Morelia is considering pumping water from the lake for municipal uses, which could reduce the lake level and perhaps even eliminate the springs that feed the lake, thus destroying this unique goodeid habitat.  Martina and her students are working to help protect the lake.

Ameca basin, Jalisco
We were on a tight schedule, so as darkness fell, we made our goodbyes with Martina and her students and drove west to Guadalajara, arriving there late that night.  The next morning, the 11th, we headed west from Guadalajara into the Ameca basin, which drains to the Pacific, to look for Allodontichthys polylepis (critically endangered) and Allotoca goslinei (endangered) and Scartomyzon mascotae.  We first visited the R√≠o de la Pola at the Highway 70 crossing near Estanzuela, about 40 km west of the city of Ameca (20 31’ 27.7” N; 104 20’ 12.0” W), one of the three sites from which A. polylepis has been taken.  Here the river was about 8 m wide with long pools from 0.8-2.0 m deep connected by short shallow riffles (see photo).  The bottom was gravel/cobble, bedrock, and sand, and the surrounding landscape was open dry scrub.  I first visited this site on 23 August 1997 and in 70 m of electoshocking took 10 A. polylepis, 48 Ilyodon furcidens, 2 Scartomyzon mascotae, and 4 Tilapia (an exotic cichlid).  My next visit, on 9 February 2000, was less productive, and in 300 m of electofishing I took only 90 I. furcidens and 10 S. mascotae.  However, this year’s trip had the lowest yield of all, with only 10 I. furcidens, 2 Tilapia, and 15 Cyprinus carpio (common carp, an exotic cyprinid) in 90 m of shocking. I’m doubtful that A. polylepis still remains at this site.  The reason for the disappearance of A. polylepis is unclear.  The site had no obvious major pollution or habitat modifications. However, on my last two visits the flow was very low, providing little of the riffle habitat that A. polylepis needs.  Perhaps flows during recent dry seasons were insufficient to support A. polylepis.

We next moved to the Arroyo Diabolos about 10 km N of the R√≠o de la Pola, to which it is a tributary.  We sampled at the crossing on the road to Guachinango (20 33’ 25.4” N; 104 21’ 33.9” W). This site flowed through a narrow canyon.  The creek itself was abut 3 m wide, deep slow bedrock pools up to 2 m deep connected by short shallow gravel riffles (see photo).  On my first visit here, on 9 February 2000, I electroshocked 75 m and took 10 A. polylepis, 152 I. furcidens, and 8 Tilapia.  The A. polylepis came out of the deep pools, an atypical habitat, probably because little of their preferred riffle habitat was deep enough to support fish.  On this trip’s visit we shocked 100 m, but caught no fish of any kind.  The absence of fish was perplexing.  No pollution was evident and the habitat conditions looked similar to those in 2000.  However, as I have speculated for the R√≠o de la Pola site, perhaps flows during recent dry seasons were so low that the fish populations were eliminated.  Whatever the reason, A. polylepis no longer occurred at this site.

We then moved west to the R√≠o Atenguillo at Highway 70 near the town of Atenguillo (20 25” 54.6” N; 104 28’ 56.4” W).  The R√≠o de la Pola is a tributary to this river.  The R√≠o Atenguillo was much larger than the other sites with a width of about 25 m and a strong flow.  It had numerous riffles that looked ideal for A. polylepis.  However, although we shocked 100 m and captured a variety of fishes, we collected no goodeids.  In my one previous visit to this river (at a site further upstream) I also did not take any goodeids, nor did other ichthyologists in earlier visits to this river.

Finally, we moved east to the Arroyo Potrero Grande, on Highway 70 about 10 km west of Ameca (20 31’ 17.2” N; 104 7’ 29.2” W).  This is the third and final site from which A. polylepis has been taken, as well as the only site from which Allotoca goslinei has been found in the last 20 years.  The creek here was only 1-2 m wide, with a maximum depth of 0.4 m, small rocky pools and very shallow riffles, and limited flows.  The banks were heavily wooded.  Allodontichthyspolylepis was taken here as recently as 1996 by Derek Lambert, but I did not see the species in my only previous visit on 10 February 2000 nor on this year’s visit.  On both of my visits flows were so low that there was no suitable riffle habitat for A. polylepis.

Allotoca goslinei has declined dramatically in abundance at this site over the last four years.  During my 2000 visit A. goslinei was common.  In 200 m of shocking 99 A. goslinei, 6 I. furcidens, and 28 Scartomyzon mascotae were collected.  However, during this year’s visit only 7 A. goslinei (see photo) were taken in 200 m of shocking, as well as 19 I. furcidens, 17 S. austrinus, and about 120 Xiphophorus helleri (an exotic).  The appearance of X. helleri may account for the decline in A. goslinei; both occupy the same pool habitat and are potential competitors.

The complete absence of A. polylepis from its three known localities and the major decline in A goslinei abundance at its one remaining locality indicate that the future of these two species in the wild is precarious.  It is too early to conclude that A. polylepis is extinct in nature or that A. goslinei is doomed, as large areas of potential habitat for both species have not yet been surveyed. During my next visit to this area I hope to survey the R√≠o Ameca downstream from where the Arroyo Potrero Grande enters it.  This area is badly polluted from the city of Ameca, but it once supported A. goslinei and possibly A. polylepis as well.  Perhaps individuals of one or both species still persist in poorly accessible areas far downstream from Ameca where the pollution has somewhat dissipated. However, even if A. goslinei and A. polylepis are found in the R√≠o Ameca, their native habitat appears to be deteriorating, and it is critical that captive populations of both species be maintained and expanded.

Springs around Durango
We spent the night of 11 January back in Guadalajara and then left on the 12th for the city of Durango, far to the north.  We sampled two non-goodeid sites on the way and arrived in Durango very late that night.  The next morning we began sampling sites in the R√≠o Mezquital system around Durango, looking for Scartomyzon milleri and goodeids in the genus Characodon.

Historically, Characodon was widespread and common in springs in the R√≠o Mezquital system just north and west of the city of Durango.  In a morphological analysis of the genus, Smith and Miller (1986; American Museum Novitates 2851:1-14) described C. audax from a spring near the town of El Toboso.  They attributed all other populations in the region around Durango to C. lateralis, a species described by Gunther in 1866 for which the type locality is unknown (erroneously listed as “Central America” in the original description).  However, recent genetic analyses by Omar Dom√≠nguez and colleagues (Doadrio and Dom√≠nguez. 2003.  Molecular Phylogenetics and Evolution, in press) indicate that the taxonomic situation is more complex, and call into question the current definition and distribution of both C. audax and C. lateralis.

Regardless of how they are defined, both C. audax and C. lateralis are in trouble.  The R√≠o Mezquital system has been highly degraded by pollution, excessive water withdrawls, and exotic species.  Only 6 or 7 Characodon populations remain extant, each isolated in a small spring.  Both species are considered critically endangered.

The weather, which had already been unusually cold and rainy, became notably bad when we arrived in Durango, with temperatures of only 5-12 ¬įC and steady (and at times heavy) rain.  There was talk of snow.  Every site was dreary and muddy.  We spent most of 13 January at non-goodeid sites, but ended the afternoon sampling the El Toboso and Abraham Gonzales springs for Characodon.

The El Toboso spring, known as “El Ojo de Agua de las Mujeres”, is located in an open scrubby, stony, and normally arid (but quite wet this trip) landscape about 200 m north of the town of El Toboso (24 16’ 30.7” N; 104 34’ 52.8” W).  The spring had been impounded by a stone wall to form a small pond (see photo) and contained numerous aquatic plants.  It is the type locality of Characodon audax, which we found to be common among the plants.  We quickly took about 40 with a few swipes of our dip nets and short pulls of the seine.  The specimens were beautiful with black fins and dark iridescent flanks (see photo), and some of the males had reddish ventral areas, although poor light and steady rain made it difficult to get a good photo.

As we walked back into El Toboso after sampling the spring, we encountered some friendly (and a bit drunk) locals, who asked what we were fishing for.  In subsequent conversation they told of how catfish had recently been stocked into the El Toboso spring for aquaculture purposes, on the advice of the state government agricultural agency. They also said that catfish, largemouth bass, tilapia, common carp, and perhaps other species had been stocked into the Abraham Gonzales springs 10 km to the south, our next destination. This was unwelcome news since several of these species, if established in the springs, could harm the Characodon populations.  Catfish and bass are predators that could eat Characodon, and common carp might uproot and eliminate aquatic plant habitat.

We proceeded to the town of Abraham Gonzalez.  The springs there originate in a series of marshy ponds on the east side of town, and their outflow is passes through the middle of town via a narrow concrete lined channel.  We sampled this channel with dip nets just as it left the ponds (24 12’ 50.7” N; 104 31’ 47.8” W).  At least some of the springs were thermal; the channel was 24-27 ¬įC despite an air temperature of only 9-10 ¬įC.  The channel had little habitat but was nonetheless full of fish.  In about 25 m we collected about 50 Characodon, over 100 Gambusia senilis (an exotic Poecliid), 7 of the native pupfish (Cyprinodontidae) Cyprinodon meeki, and about 50 Tilapia.  The Characodon here looked generally similar to El Toboso, although they were not quite as dark (see photo).  Failing light and rain made photography difficult.

We spent the night in Durango and the following morning sampling non-goodeid sites, before heading towards the city of Le√≥n, far to the south and east. Along the way, about 70 km southeast of Durango, we sampled for Characodon at the springs in the town of Amado Nervo.  Our site was in an open grove of cypress trees on the south edge of town just north of Highway 45 (23 50’ 33.2” N; 104 11’ 12.1” W).  Here a series of small springs entered a small (< 1 m wide, 0.3 m deep) stream that drained the town.  Using dip nets, we collected about 30 Characodon and 1 Tilapia in 25 m of sampling.  These fish were much lighter in color than the El Toboso or Abraham Gonzales specimens, and had dark spots/blotches on the sides and a faint reddish cast to their abdomen (see photo).  Their appearance matched the description of C. lateralis.

Río Duero, Michoacán
We left Amado Nervo near dusk and arrived in Le√≥n at about 2:30 a.m. I had developed a stomach illness that afternoon, so it was a long ride, and I was never so happy to collapse into bed. The following morning, 15 January, I felt better and we headed south towards the R√≠o Duero to look for Scartomyzon austrinus and Lampetra geminis.  On the way we briefly sampled the R√≠o Turbio, Guanajuato, a R√≠o Lerma tributary, at the Highway 41 crossing (20 43’ 15.3” N; 101 42’ 15.7” W).  In the late 1960s this site had supported at least three goodeids and a variety of other fishes, but now it was polluted and we caught no fish.

We arrived at the R√≠o Duero, another R√≠o Lerma tributary, in mid afternoon, and sampled at the crossing on the road to Et√ļcuaro (19 53’ 3.6” N; 102 8’ 53.9” W).  I had visited this site previously, on 7 November 1991, and taken a number of L. geminis, S. austrinus and Algansea tincella (a native cyprinid), but for goodeids only a single Goodea atripinnis.  Elsewhere in the Duero system I had done much better, catching a few Alloophorus robustus and many G. atripinnis, Skiffia multipunctata (endangered) and Zoogoneticus quitzeoensis.  However, on this year’s trip the goodeid yield from the Et√ļcuaro site was much better.

We began by electrofishing some narrow (1-2 m), deep (1-1.5 m), clear spring channels that entered the river just above the bridge.  I had been unaware of these channels on my previous visit.  Fish density was low in the channels, but diversity was high.  For goodeids, we took a single Allotoca dugesi (endangered; see photo), to my knowledge the first record of this species from the Duero system, 2 S. multipunctata, and 2 Z. quitzeoensis.  The male S. multipunctata were particularly attractively colored (see photo).  We also took 3 L. geminis and 3 A. tincella.  We then moved out into the river proper, which was 8 m wide and 1-1.5 m deep, with a clay and gravel bottom (see photo).  It was surrounded by agricultural lands and was swollen with muddy irrigation runoff.  The strong currents made sampling difficult.  In 120 m of shocking we collected 7 more S. multipunctata plus 11 L. geminis, 7 S. austrinus, and 13 A. tincella.

With completion of the sampling of the Río Duero, our fieldwork was over. We packed up and made the long drive to Mexico City, arriving, as had become our habit, long after midnight. The next day we organized gear, packaged specimens, bought souvenirs for our families, and visited with friends before returning to our homes on 17 January.

Summary
Our trip yielded both encouraging and discouraging results concerning goodeids.  On the positive side, Girardinichthysviviparus persisted in Chapultepec Park, La Mintzita continued to provide a home to five goodeid species, Characodon hung on in a few springs near Durango, and the R√≠o Duero remained a refuge for at least three goodeid species.  On the negative side, we could not find any Allodontichthys polylepis within its known range, the single remaining population of Allotoca goslinei had decline precipitously, and the La Mintzita and Durango springs faced imminent environmental threats.  The future does not look promising for most goodeids in central M√©xico.  Protection of those sites that still support goodeids and other native species must be a top conservation priority.  Concurrently, captive populations of all goodeids species must be maintained and expanded, since the survival of many wild populations is in doubt.