Inland Fishes of California
Revise d and Expanded
PETER B. MO YL E
Illustrations by Chris Ma ri van Dyck and Joe Tome ller i
NIVERS ITyor ALfFORNJA PRESS Ikrkd cr I.", ..\ n~d e ' Lon don Universit }, 0 Ca lifornia Press Herkdey and Los Angeles, Ca lifornia
Uni ve rsity of alifornia Press, Ltd. Lundun, England
~ 2002 by the Regents of the Unive rsi ty of Ca lifornia
Library of Cungress ataloging-in -Publ ica tion Data j\·[oyk, Pen: r B. Inland fis hes of California / Peter B. Moyle ; illustrations by Chris Mari van D)'ck and Joe Tomell eri.- Rev. and expanded. p. cm. In lu de> bibl iographical refe rences (p. ). ISBN 0- 20-2.2754 -'1 (cl ot h: alk. papa) I. rreshw:ltcr lishes-Cali(ornia. I. Title. QL62S C2 M6H 2002 597 .17/i'097Q4-dc21 20010 27680
1\!UlIl.Ifaclu rcd in Canacla II 10 Q9 00 07 06 0 04 03 02 10 ' 1\ 7 b '; -\ 3 2 1
Th paper u!)ed in thi> public.ltiu(] 111l'd., the minimum requirements "fA SI / i': ISO Z39.4H-1992 (R 199;) ( Pmlllllh'/l e ofPa pcr) . e Special Thanks The illustrations for this book were made possible by gra nts from the following : California-Nevada Chapter, American Fi she ries Soc iety Western Di vision, Am erican Fi she ries Society California Department of Fish and Game Giles W. and El ise G. Mead Foundation
We appreciate the generous funding support toward the publication of this book by the United Sta tes Environme ntal Protection Agency, Region IX, San Francisco Contents
Pre(acc ix Salmon and Trout, Salmonidae 242 Ackl10 11'ledgl11 el1ts Xlll Silversides, Atherinopsidae 307 COlll'er,
This book is the fi rst revision of the one I boldly began writ Common name, Scientific l1am e ing in 1972, when I had lived in California for just two ye ars . Identification Writing it was my way of getting to know a fish fauna that Taxonomy was a mix.ture of familiar and unfamiliar elements. The fa Names miliar parts were introduced fishes, most of them native to Distribution the eastern part of this country, where I had received train Life history ing as a fish biologist. The unfamiliar parts were native Habitat fishes, most of them occurring only in California. The first Nonbreeding behavior edition was published in 1976, and its principal message was Feeding habits th at we kn ew astonishingly little about many of the fi shes, Age and growth especially native fishes. Since that time, I have been collect Reproduction ing information to fill in knowledge gaps and to correct er Early life history rors in the first edition. The job is far from finished, but, Status given the precarious state of the native fi shes, I thought it Rating important to summarize once again what we know about Abundance them. I sometimes wonder if complete accounts of the sys Management tematics and natural history of many native fishes can be Referen ces completed before the y go extinct. Species accounts for sev eral fishes are already obituaries, and others may become so Identification This is not a complete species description in the near futme. I can only hope that the information pro but a compilation of features useful for scpcnating the vided in this book will help to reduce the loss of our native species from other California fi shes. Te rminolo~w is defi ned fishes. At the same time, managing th e altered aquatic in the introduction to the key. ecosystems of California requires knowledge of the alien Taxonomy This section is especially important for species fi shes that now dominate many of them, including favorite for which there is controversy or uncertainty about system sport fishes. The ad aptations of alien fishes to the Califor atics or that have a confusing taxonomic histor y. It is used nia environment and th eir impact on native fishes is there to discuss advances in our understanding of the sys tematics Core also a major theme. of the species . Minor questions of name changes or long The species accounts are the most important part of this settled taxonomic qu es tions are usually mentioned in the book. They are preceded by chapters providing overviews of Names section of each species account. th e di stribll tion , ecology, and conservation of th e fi shes, fol lowe d by n key to Illake identification easier. Each species ac Names The common and scientific names used here, wi th cou nt is organized as follows : a few exceptions, are from the American Fish eri es " ,)( i et ~" s
IX BASE MAP of Califomla with STATUS SYMBOLS zoogeographic province li nes NATIVE ALIEN ~-l ~ STATUS extincU A extirpated @ extirpated OISTRIBUTION -EJ SYMBOL o localized 0 range: _ present small, I threatened! l===::J former --" B highly localized, ~. endangered c::::J absent stable or @ declinmg \ J ~ special concern C limited EJ distribution @
""hwo'·'A watch list widespread uSYMBOL~,~ 0 stable @) ~ amphidromous stable or E aggressive estuarine " increasing invader ~anadromous {t @ Figure 1. Symbols used on di stribution maps to indicate distribution, sta tus, and life style of each fish species,
1990 List ofCommon and Scientific Names ofFishes from the I. Native species United States and Canada, The origins of the scie ntific A. Extinct/extirpated, The species is gone from Califor names come from many sources, but most frequently from nia (extirpated) or gone from the planet (g loball y ex tinct). Jordan and Evermann (J 896). B. Threatened or endangered. The species is likely tn be come extinct or ex tirpated in the near future «25 yea rs) un Distribution This section describes th e distribution of each less steps are taken to save it. An endangered species is on a species, fo cusing on California. The distribution maps pro more rapid path to extinction than a threat'ne I 'pecies, vided are designed only to give a general idea of the distri Most of these species are form ally listed by either the state bution of l'ach species, not site-specific information (Fig, 1). or the federal government; some are not (but probably Larger distribution maps for each species are available should be), The formal status of each threatened species is through the Information Center for the Environment at the given in the account. University of California, Davis (http://ice.ucdavis,edu). C. Special concern. The species is in decline or has aver), Even these maps should be regarded as snapshots of the limited distribution, so special malluge ment is needed to present distribution of each species, because distributions keep it from becoming threatened or endangered. are changing constantly, as the lan dscape changes under hu D, Watch list. The species appears to be declining but is man influence, native species decline and introduced not yet in serious trouble. Its popuiJlions must be moni species expand, tored to see if special protective action is necessary. E. Stable or increasi ng. The species is abundant or in Life history Iv[ uch of the information on the habits of Cali creasing in population. fornia fishes is hidden in the "gray literature" of unpublished theses and reports, I have tried to be as comprehensive as II. Alien species possible, but no doubt I have overlooked some of these im A. Extirpated in California. The species was once es tab portant sources of information , (If you are aware of a docu lished but the introduction failed. These species are men ment I have missed cOlltaining useful tidbits, please send me tioned only in t~l mily accounts. a copy, Maybe [ can use the information in the next edition !) B. Small, highly localized populations. The species is es [jee history in formation that is not referenced is based on tablished in just a handful of 10 al ities an is stable or de unpublished J ata or observations of my own, clining in numbers. C. Localized likely to become more widesprea d or alread y Status In this s ti OIl, [ rate th e status of each species in the wi desp read but not abundant in most areas. Allern.ltdy, it stale dnJ th n disc uss abundance tTends and management may be fairl y co mmon but is declining. The speci s is usu needs. ,t, rating syslem is as follows: ally J recent introduction and is just starting to exp x PR EFAC E I'," ,gl! , H it is a long-establis hed species th::r t is only region The word lake in this bo ok is reserved fo r true lakes ;lnd all) ~ b uJ1 d a nl. is not used to refer to reservoirs, DO matter haL the agen O. Widesp re ad an stable. The species is widely distrib cies who build re ervoirs cal l them. This l L~age i nsistcnl uted but seems D h References In the species accounts, the references are num BLM. Bureau of Land Manage ment bered and listed for the most part in the order in which th ey CDr , California Department of Fish and Game are cited in the text, by author and date, in an effort to save space and make the text more readable. Thus a listing like DvVR , alifornia Department of Water Resources "3. Rutter 1908" is a citation near the beginning of an ac NiVl f S, . ::llional MJrine Fisheries Service count, with a more complete citation to be found in the Ref L ':C, The Nature Conservancy erences section at the end of the book. USFS, U. S. Forest Service Term inology The classification system used follows the USFWS, U.S . Fi sh and Wildlife Service fourth edition of .\llo )'Je and Cech ( 2000) , which in turn fol US GS, C S. Geological Survey lows Ill lJs tly Nelson (1994). The result is a fairly major re ordering from the flrst edition. The terminology used to de For length designations, the follo wing abbreviations arc scribo: aU aspects of fish biology is al so based on Moyle and used: SL, standard len gth; TL, ttl tal le ngth; FL, fork length. Cech (2000), rell ecting new understanding of various as All are deflned i.n the introduction to the key in th e Identi pects of ichthyology. For exa mple, J use the term shoaling fi cation chapter. where most American biologists would Llse the word school ing. I reserve schooling as the word referring to aggregations of fi shes (shoals) that are polarized and swimming in syn Illustrations Most of the pen and ink drawings in this book chrony (schools). are copyrighted by the artist, Chris M. van Dyc k. These To improve readability, scientific names of resident CaJ drawings are available to be used for nonprofit purposes at ifornia species are in most cases used just twice: once in the no cost by members of the Ameri can Fisheri es So ciety and key and once in the account of the species. The common others, provided a request is made in writing to th e author names are in any case increasingly more stable through time and the artist (l 123 Kerria Avenue, McAllen, TX 7850 I l. than the sc ientific names. Other uses should be arranged with the art ist. I' R U · A C E ~\ Ackn owledgments This book would not have been possible without the col flil al draft, doing much more than I had any right to expect bboration of do/'Clls of biologists who shared information him to do. Ronald A. Yo shi ya ma worked with me on a num and insights with me over the years. The large grou p who ber of reports and review papers important to this book, in helped me develop an understanding of California's fasci cluding the second edition of Fish Species of Special Co IIcern nating fishes during my fi rs t five years in the state are in Calijo nzia, which is the foundation of many of U1e native acknowledged in the first edition, published in 1976. I have species accounts. His exhaustive research ha~ given many many memories of their patient kindness and willingness to accounts increased depth and accuracy. The support of the di g through files to enlighten me. For this edition I Giles W. and Elise G. Mead Foundation for this work is ;1Cknowledge most individuals who helped me by listing greatly appreciated. them as a "pefs. comm." embedded in the text. Those oft In the ten years or so in which I worked on the IllJnu repeated two words represent hundreds of e-mails, letters, script many gradua te st udents and postdoctoral scholars and conversa tions-and they convey the important point who were part of my fish ecology group contributed by pro th at this book is in some ways a project of the entire viding information and id eas, reviewing sections, or just community of fisheries and fish biologists in California. For se rving as so unding boards for thoughts that st ruck me those whose knowledge or insights I absorbed without during my reading and writing. They include Do nald Baltz, acknowledgment, my apologies. Some special acknowledg William Bennett, Anne Brasher, Elizabeth Campbell, ail ments are nevertheless required. Dethloff, Joaquin Felici:1I10, Leslie Ferguson, Mark ard, Jerry J. Sm ith and Larry R. I3rown patiently reviewed Nathan Goedde, Bruce Herbold, Jeff Koz lowski , Ro be rt many species accounts and improved them with cr itiques Leidy, Theo Light, Michael Marchetti, Scott M:lte rn , LesJ based on their impressive kn owled ge of the fishe s. The entire Meng, Paul Randall, Robert Schroeter, "led Sommer, Eliza manu scr ipt was reviewed by ,,yendell L. Minckley and Robert beth Strange, Bruce Vondracek, and Rolland \-,,!hite. A. Fisher. Minckley's humbling comments on my writing Others who re sponded repeatedly and enthusiastically to style were very helpful and resulted in the deletion of the my requests for information included Rand all BJxter, Ca rl word the a t leas t 7,000 times. Selected sections ben efited from Bond, Jo se ph J. Cech, Jr., Barry CoslJ-Pierce, Walter R. com ments by William A. Bennett, Eric Gerstung, David W. Courtenay, Jr. , Michael H. Fawcett, Tim Fo rd, Dan Ga le , Kohlhorst, Robert L. Leid y, Scott A. Matern, Phil Pister, Don Michael Giusti, Sharon Keeney, 10m T. Kisanuki, Dennis ald Sada, Gary Scoppetone, and Christina Swanson. Lee, Stafford Lehr, Douglas Markle, J. D. McPhail, W. L. The timel)! book on introduced fishe s in California by MinckJ e)" Lind a Pardy, Stewart Reid, Terry Roelofs, Gary Willi am A. Dill and Almo r. Co rdone ( 1997) saved me im Sco ppetone, Ramona Swe nson, Camm C. Sw ift , Thomas 1.. mense amounts of ti me uncovering information and check Taylor, and David Vanicek. I am grateful to members of the ing fa cts. Their wry comments on in acc uracies in my first Exec utive Committee of the Ca lifornia- evada Chapter or edi tion rt'g;lrdi ng tim t' s and places of introductions are re the American Fisher ies Society, who arran ged to provi de Il 'clt'd in imp rove men ts in this edition, even though I still funding for the black-and-wh ite drawings, including I'd l' O il ,} secn nd nr l' source (their book). iVIichael J'vleinz, Kathy Heib, Jean Baldrige, Ra mo na Swen P'l t rick K. Cr ~ lin, mo'c than anyon e else, kept my re son, Camm C. Swift, Pat COllI ton, Alice Low, and Denn is ~e Ireh r r oj cc t ~ going wh ile I \ as in th e throe' of writing the lvlcbvan. For the color in sert Kenneth Hashagen :ura nged xi ii fun ding from t h~ Western Div ision of the American Fish 1r.. amm . Swift:, C rl BlInd, t.lichJl,j Be.ll, ,llId Recve eri es Society; Chuck Knu tson, [rom the aIi fo rnia Depart Ba iley. while Christophe r M. De lV ce~ permittt'd 111<:: to u:e nl<: nt of Fish and Game; and Robert A. Leid y, from the U. '. three or his fi sh prints. My thanks to each of them. Env ironmental Protec tio n Age ncy. I have b en fortunate to wo rk wi tli a great group of be It has been a continuing pleasure to work with Chris M. ult)1an d staff in the Department of Wil dlife, fish, .Ind CU:1 van Dyck, who did most of the artwork, including the won servati on 8ioI08)' at the Universityof C.ili Cornia , Davis, \ 110 derful drawings of salmonids created originally for the 1976 defi ne the wo rd co Ileg iali t),. I particularly Jppreciatt: th e edition. It is h,nd to imagine this project succeeding with leadersh ip f th " three d pa rtmental chairs during the long out her skill, energy, and suggestions for improving the gestation of this boo k: Daniel And rson, Josep h Cech, Jn t! presentations. Those interested in using her copyrighted Deborah ' Hiot t-Fisk. I am also grateful for the 'l ssis t.l Il CCof drawings should see the section on illustrations in tbe th ose mcmbers of the departmental stall who helped iron Preface. out the many problems, major and minor, 1 faced in putting It has also been a pleasure working with Joseph Tomel the book to gether: Marj orie Kirkman-Iverson, Della Nuncs, leri to arrange use of his superb color portraits of native and Peggy Davis. fishes. Alan Marciochi created 27 of the fish portraits, Finall y, 1 appreciate the patience and help of Doris holdovers from the first edition. Archival drawings by H. L. Kretsch mer, executive editor at the University of Cali fornia Todd were made available by the National Marine Fisheries Press, in putt'ing t.his book together, and the wonderfull)' de Service (W\-\f\v. photolib.noaa.gov). Other drawings were tailed editing of the tlnal manuscript by Peter Strupp of provided by David S. Lee, Paul Vecsei, Walter R. Courtenay, Princeton Editorial Associates. xiv A C KN () \If r ED G ME T S Gobies, Gobiidae Gobies are adapted for bottom living in shallow an d inter reaches of es tuaries. In California th ere are 16 spec ies, 12 of tidal watns. Their most distinctive feature is the ventral them marin e. Three spec ies can spend their entire life cycle cone-shaped suction CLIp formed by the co mplete union of in fresh and brackish water: tidewater gobI', shimofmi goby, the pelvic nns. This cup can be used for clinging to rocks in and yellownn go by. In addition, longjaw mudsucker occ urs the i:lCe of backwash from waves or strong tidal currents often enough in low-sa linity reg ions to justify trea tment in and for climbing over waterfalls on island streams. Their this book. The arrow goby (Clcl'f:'llllldin ios) is a tidal mud bodies are usually elongate, their heads blunt, their mouths nat dweller that occas ionally enters fresh \V,ller at the heads terminal, th eir two dorsa l fins separated, and their eyes of estuaries and coastal lagoo ns. close to the top of the head . They are small (few grow The shimofuri go by and yeLl owtin goby are sp ecies in longe r tha n 10 cm TL) and include the smallest vertebrates troduced from As ia. Additional alien species of gabies GIll k110W ll (8-10 ml11 ,IS adults). These features reflect fishes be expected from ballast wa ter introductions. The shimo that live in unlikely places, such as burrows of marine in furi go bI', for example, is one of three members oC the ge nus wrtebrQtes or under stones, and ambush or grab small Tridelltiger introduced by this route. The chameleo n go b}', prey. T trigol1occphnlus, is a marine species found in San Frall Although there are more than 1,900 species in the goby cisco Bay and Los Angeles harbor, while the shokih aze fa mily (circa 7% of all fishes!), most of them are tropical and (bea rded) gobI', T barblliatus, is a brad,ish water species marine. Com paratively few species have invaded fres h wa known only from recent (1997-2001) specimens co ll ec ted tn, but fres hwater gobies exist worldwide, especially on in the Sa n Francisco Estuary. It app ea rs to have a 'rowing tropical oceanic islands. Many species, however, are tolerant population in brackish water. Because of un certainties in its of low salinities and are occasionally found in the upper sta tus and ecology, it is not included here. Ti dewater Goby, Eucyclogobius newberryi (Girard) the tlu dorsal nn, 9-13 elements in the second dorsal fi n, 9-12 elements in the anal fin, and 8-10 gill rakers. The ir Identifica tion Tidewater gobies are small (seldom larger bod ies are gray, brown, or olive, with dark mottling or neck th an 50 mm SL), wilh elongate, blunt tails and pelvic fi ns ing on the sid,s an d back. Living fi 'h are nearly translucent. un it ed to fo rm a sucker. The upper quarter to third of the Dorsal fi ns are mottled, pelvic fin s are )Iellow or dusky, ,1l1J first dorsa l 1111 is clear to crea m- colored, ,,,hile th e seco nd the anal fin is dusky. In breed ing fe.males th e sides and dor dorsal Fi ll is longer and sy mmetrical. similar in size to the sa l and anal 6ns turn vdry in g degrees of bl ack; in the most ~l11al lill. The mouth is brge and obli que, the m~L\.i llar y ex treme cases fi ns beco me ve.lvet)' hldck .j 0 Fig ure 143. Tidewa ter go bI', 33 I11Ill SL, Ali so Cn.:ck la goo!), Orange ,o unty. Drawing by amrn C. Swi ft, fro m Swift t: 1 al. ( I')K') ). bl ocked 'e, sona LJ ),· (mm th e 0 ea n by sa nd ba rs an d are lyp ically brackish and cool (slimmer temperatures 16- 25°C) with bottoms of sa nd and si lt (2, 3, 4, 5, 6). The gobic J.lre fer salini ties of less than 10 ppl .lnd as J conseq uence are ge ner.]lIy found in upstream portions of larger la goons (J 7) . However, they can live at salinities or 0--4 1 ppt (2) and will breed at sal inities of 2-27 ppt ( ). The)' can live :lJld bre d at tem pera tures of 8-25°C (2, 3). \Nell-oxygeIlJted water is al so required, so they disappear from la goon areas that stJgnJte or stratify. Optimal lagoon habit;)t ; are sld low sa ndy-bottomed areas 20- 100 cm deep surrounded by beds of emera-e nt vegetation. Open areas Jre cutical for brecdino , whil e vegetation is critical for overwin tering sur se parate genera (L ep idogo/JiIiS iepidlls, Cleve/andia ios, Jlyp vival (providing a refuge from hi gh flo ws) and probahly 1111 5gil/Jerfi, Qllietllill y-C£1l1da, Gillichthys 111irabilis) (1). feeding as well (2, J, 4, 7). Tidewater go bies have bee n found in low- gr'1di ent sec Names EII -crela-gobill) translates as true-C)/cloid-goby, re tions of in flowing streams as mu ch as 12 km upstream from ferring to the cycloid scales (many gobies have ctenoid a lagoon (4) . Breeding does not occur in th e streams, and ~C1 le ); Ilcwbcny i is after J. S. Newberry, a professor at Co the fish present are mainly juveniles that have moved up lumbiJ University and advisor to the U.S. Geological Survey from lagoons. In the laboratory reproduction can occur in team that first coiJected tidewater gobies in 1854. Goby is fres h water, but in th e wild it seems to occur onl y in brack apparently derived from gobio, the Latin word for gudgeon, ish water. Although they are often the most abundant in a fres hwater gobyl ike cyprinid of Europe. Tidew,lter goby is their lagoon habitats, they can be as sociated with fres h the official common name even though it is not particularly water fishes (arroyo chub, gree n SLinfish, mosquitoflsh), descriptive of the fi sh's habitat. anadromous fish es (rainbow trout, threespine sticklehack), and euryhaline fi shes (staghorn sculpin, prickly sculpin, Distril)ution Tidewater gobies are endemic to California. starry flounder, California killifi sh). They are found in lagoons of co,lstaJ streams from Tillas The gobies are not particularly good swimmt' rs , moving sl( ugh, at the mouth of the Smith River (Del Norte along the bottom in short bursts, occ1sionall), swimming 1I p ~ oullty), south to Agua Hedionda Lagoon (San Diego to grab passing or hovering prey in midwater al ong steep COLI Ilty) (2, 17 ). They are absen t from areas where the coas t banks or among emerge nt plan ts. \\11 en abundant they oc line is steep and streams do not form lagoons. Their north cur in "loose aggregJtions of a few to several hundred indi ern limit on the C1lifornia-Oregon border is unique and is viduals, with no apparent size segregation" (2, p. 6). The)' es pres Limahly related to their difficulty in di spersing through cape predators by swimming in quick dJshes or J--2 Ill, into the ocean, especizlilv when dominant currents flow south. vegetation if it is nearby. The)' Llsually do not burrow into Hi storically the y were present in at least H7 coa stal localities loose substrates to esclpe predators, Jlthough this hehavior ,m d .lb sent from ahout 40 deemed suitabl e for th em (2 ). has been observed in one population (4 ). Predators (or ,It Th 'y are now go ne from mJny localities, inclucLing San least native predators), however, do not appear to be im Fran cisco Ba y. portant re crulators of population si ze in lagoons in 5lHI them California. In stead, populations :tIT contro ll ed bv environ Life History Tid e\ ater gol ie are a lapted for life in -oastJI mental conditions. ''''hen strea ms flo od and lagoon b'l rrier lagoons rea ted by inn wing stre'lms. 'I he lagoon, are ar hreached, creating a strllllgly tidal environment, I' op u 'II [) I \\' ,\TFR GOllY ~ .'l blj on ~ plu mmet, although they quickly recover in summer, eggs eadl over cl lllonlh~ (3). [tl a litelill1c J I... m.tlc J. In ' ,1(1 1,1 Y I1l'f' lago on Sw ift tit al. (4) e timated that th<: apable of producing 2,400-!.IlOO egg~ if he ,urvivc:, pup ulati(ll1 ~ elll fl"Qm 11 milli on fis h ill JaJluar'y to 11 ,000 through two ~p a w ni ng seasom, 1,200- 2,40U egg:. If he ur by th e Co lio win o Jun e, 111 al hc:r lagoons peak meal] densities viv 5 thru ugh onl} one ( ' 7) . of'obies of 5-30 fi sh per 'quar meter ha ve bee n r co rded, Spawni11 7 behavior of ti ciclV,l la gob) is hi gh l)' UI1 U'ual, dropping to nearly undetectable levels at so me tim es (3, 4 ), becau c fem,1les compete inkll. c1 It. r male, and are the'n.' Densities are high es t dmong emergent or submerged vege f re rhe more bri ghtl y cu lor cl and Gggress ive sex (:Jl.l\fa les tation, More northern populations are not as dense, sug cOl1 stm ct ve rticall urrOlvs for spawning, whiJ1 they defen d ges ting that their numbers are regulated in part by preda from other IlJales, t th e SJI11 C lim fem, ti es !efe nd territo tion from salnJOllids (16), ries an.Jund their ..: hosen male and bu rro\\' from other re They reed mainly on small crustaceans (ostracods, gam males, wh ich oftl!n leads to hghts in vo lvi ng "lin cli sp l,l ) I ~ , marid amphipods, mysid shrimp) and aquatic insects, cs tail-beating, ch argi ng, biting,j.lI v loc king, and wrc:stllng" ( LJ , llcci .illy chironulllid midge larvae (2,7), These benthic prey p, 33), I- 'males actively court males ill burrows, approach arc Ld l-'Lured by three basic techniques: plu cking individu in g with stiffly ~ lr checl body and dark, erect dorsaJ anti anal als from th e bottom, sediment sifting, and midwater cap tins, \ fem ale th en tests the readiness of a male to mate by ture (7), The most frequ ent method is plucking individuals trying to enter the burrow or sti cking her head into his from th l: bottom, usually with a sideways turn of the head, mouth, One re 'ponse is for the male to retreat into the bur :V[ajor prey (Corop hium amphipods, chironomid larvae) row and plug the entrance with sand, Another is to let the that live in tub es in the bottom have to be grGbbed with a fcmal e enter. rVlales may sometimes ('merge fro111 their bur quick upward motion of th e head to pull them from their rows to court females JS well. Once a pa ir is in a burrow to tubes, To capture small prey, a mouthful of sediment may geth er, the male usually plugs th e entrance with sand and be grabbed, churned in the mouth, and expelled through the pair remains in the burrow toge ther for 1-3 d::t ys , At th~ the gill rokers, retaining the prey, Midwater capture tech end of the period the female attaches her egg:; to burrow niques involve hopping off the bottom and swimming up to I,valls in a single layer, where they .l]'t: ferti li zed by the male, tapture passing prey, At any given time dietary breadth in a The femal e tht: n !cave s, and th e male replugs the burrow en gob)' popLll~tion is low, and individuals are highly selec tive trance, Each fe male spawns with just one l11Gle each time, in fe eding (7), However, diet does change with season, and and each male usu ally spawns with just one female (17), the gobies opportunistically feed on abundant prey in dif Swenson (9) speculates that femal es compete for mal es ferent habitats, Juveniles and adults have similar diets, but because the burrows allow males to incubate onlY'1 rei.llil'cl:' juveniles feed more or less continuously while adults feed small number of embryos at a time, Burrows are co nstructe d mainly at night (7), in anoxic sediment, are narrolV, and have just one entrance, Tidewater go bies are for the most part an annual species which is plu gged once incubation begins, Low oxygen leveb with only an occasional individual living longer than a year likely to occur in burrows may limit the number of embryos (2 ,3, j 7) , This p::t ttern is reilected in length-frequency dis for which a male can care, and this, combined with the time tributions, which typically have two modes in winter, one and energy males must spend taking ca re of th~ burrow Jlld around 15-20 mm SL and another around 30 mm SL As the young, makes maJes a scarce reso urce, season progresses both groups increase in average size, but Males guard embryos for 9-11 days without fe eding, The the abundance of smaller fish increJses, while the abun elliptical cmbryos dangle from the burrow ceiling b)l a dance of larger fi sh decre cl ses. Maximum size seems to be singh: thread each, until they hatch, The male fans and rubs around ~ O mm SL, and the largest fish are associated with the embryos as they dl:l'elop, but once they h::ttch he luses marsh habitats (3). Fish larger than 40 mm SL are rare, interest. The larvae, measuring 4-5 mm SL, emerge from Reproduct io n occurs at all times of the year, as indicated the burrow and swim upward to join the pl ankton, They be by femal es in va rious stages of uv::trjan de.vel opment (8), come benthic aga in at 16- J8 mm SL (2), everthe k ss little spawning occurs from December through March, iVlatur it y ,t:ls in at about 24-27 mrn SL, and mature Status IB, The tidewater gob)' Ivas li sted as FnJall ge red by tish may breed mo rc or less co ntinuo usly [or several the SfWS in 19'14 and has had Cully prot cred taLu s from month:" Fe mal e, produce 150- 1, 100 egg for each spawn the sta te of C"tlifornia since j 987, The listing i . ntro'ver ing, the number il1o-easing in J more or less linear fashion , ial beca use th fi , h apparentl y has sOlm: fairly se lire p p with [i.s h size (2, 3). Swenso n (3, 17) fo und th at F= J7SL Yd mill ulati ollS and is at times amazingly abundant. Lhe status - (i 2 was a reasunable pred ictor of number of ova rian eggs , is merited because each population is isolated from other Eac.h f male "";H1, pawn vcr 1- 3 weeks for se vl!ral months, populat io ns and subject t e.x tirpation through myriad fac up to 12 time" spa wn ing all ggs .It one rime, T hus one fe tors, Somewhere between 25 and 50 perce!l[ of its popula male I11cJsurin g 43 111m SL laid six cl utches averagin g 83 tions ha ve been )t 5t in the pJst 100 yea rs. most uf them .j 3~ l ; 0 B t E S , GO B t ) D A [ so uth ofPoint Conception (2). In San Luis Obispo Count)' 6 g )ons in summl!r (or tiJat flushing, 10 preven t !londing nf of 20 popubtinl1 Sdisappeared between 1984 and 1989 (0). ad l.)(~n l lanJ, III reduu! nOt Jed J n:as th.lt pl'tlcillCe Il1J)S Ithough the fis h have pehlgic la rvoe, ge net ic studies in dicate quitoes, tu earn .lwa) agnlultun.1 r{,lIutanb t hat cause that each population rare l ~' has contact with other popula anOXl J, Lo in reast? thc arca or mild flats for hirds, to admit Ii n~ ( I l ). nnd natu ral recolonization bee mes lncreasi ngl }' .11lJdromolis II 'h, JmJ even tt) impnwe bt'acilcs for slIrfing unlikely as more and more popuiJtions disappear and as re ( 12) Thegcllcral concept i lhat tid.:" rlush ing i~~gonJ" ror maining popul atiun become more restricted in their ha bi West Coast es tua ries becallse It occurs n.ltu rally on the Ba~L t:lts. They are also prone 0 loca l ex tinction because they ar Coast (11) lInfortullillely, most small C. diforn ia es tu r 1[l F \\ \ T ERr; tl R \ 4.1,; qU lring and m,l naginp, \'dland, m.1I1dging <:s tuaries, fixing le~ from which it has been lO~1 (as h~ be J1 dcmonslratl:d watershed" reducing po ll ut io n, and gentTJ U,' impro ving [151) nd serve as li vi ng proof that beLl"r wmiltlons h.I\"t~ the t: IlViro llI l1en t in which it lives. Ye t th~ goby I, abo ,\ very n: tLll"ll d. OC;1 ri y a Cal iforn ia with many tidewater gilby sen sitive ind icato r or w,llershcd conditions and of the popul.i ti ons will be ,\ bl·rter place tor all 01 LIS . hea lt h of c l<] stal 1 ,lgo u n ~ , Chances are that a watershed, es tuary, or la goon without tidewater gobies is also a poon:'r References I. Bird sollg e! ,d. 19o1:L 1, S,,,irl c:t ,II. I,:)H'I . 3. Swen environnJ E' nt f'or molny other native spec ies and is in ales. so n 1995. -t. Sw ill et JI. 1997. 3. Wang 1981. 6. \\',Ing 1')86. 7. healthy and sustainable environment for humans. The ti de Swenson and k ray 1996. 8. Gul dh.:rg 19n . 0. \ve ll sun 199 7. water goby is also a wonderfully res ilient species; it will re 10. K. Wo rcester, COF " pers, cumm. 1':) 89. I I. Crabtree 10 '5. 12 . spond almost instantly to favorable conditions, building Cap~U i 1997. 13. La fferty ancl Page 1997. 1-1 . ,vlatern 1999.15. populations nllmbering in 1he millions. Thus, provided Swift et <11. 1993. 16, C. C. Sw iil, pers. (amm. 1999. 17. SWelNlIl large wt:tlands are present ( 18) , it can be restored to estuar 1999 . Pl. La ffer 1)t et 31. J999a,b. Figure 144. Longj<1w l11ud su c: kcr, 9.8 cm SL. Ca lifornia. Ura",ing b 1\ . Marciochi. fin is small a nd low (4-8 spines ); t he seco nd clors~i1 fin is well developed ( 10- [ 7 elements). The anal fin is short, Ivith 9- 17 elements (usually 10-[ I rays ). The pectoral fins ,1I"e rounded, with 15-23 rays. They have 10-1 6 gi ll r, kers on the first arch. Scales Jre small, cycloid (ctenoid in juveniles), and embedded in irregular rows, with 60- 100 in the lateral series. Scales are largest on the cJudal peduncle, beco ming smaller towa rd the head. Th e anterior porlio n of th e bell y is usually without scales. MLldsuckers are dark brown to olive on the back and sides with ye llo vv ish bellies olnd fre quently have a row of faint ve rtical bars on the sides. Ju ve niles «25 mm TL) have a smaller mouth (reaches to the back oCthe eye) , eyes more on th e sides of Lh eir heads, a dark blotch on the rear of the first dorsal fin, and o Ct en abollt 8 vertical bars on the sides. Taxonomy Longjaw rnudsuckers show some morpho logical and geographic variation (1 ,2), but not enough to brea k the species into subspec ies. They are part of:t gr up of related bu t rnonogeneric go bit:s from the ali forn ia reg ion (3). Longjaw Mudsucker, Gillichthys mirabilis Coope r Names Cill-icllthys means ,il l's fi 'h, nJmed for Theol! r ' Gi ll, J 19th-century ichth)iologist who worked on gobies. Identifica tion Longja\\' mudsuckers are heavy-bodied go Mirauilis mea ns wo nderful, perhaps ret-leeti ng J. G. Cu pr::r'. b, >. with L'xcce dingly long upper jawbones that nearly reach admirati on for their strange appearance and abilit~ to live the (J pt: n:ular ()pt'lllng in adu lts. Their heads are bro ad and in mud fbts and tolera te ex:tre m( conditions. They are wdl tbt, with ,mall widel)' spacl:d eyes on to p. T he first dorsal described by Lh eir common naml'. 434 G ( 1 k I E ', G OA I r U A E Oistribution Longj,1\\' mudsuckers occur fro m Bal1ia Mag c1udjng algae, isop cis. 'lrnphipods. anJ ~mall fish ( 12, 15, de lena in Baja Ca lif rn ia north to Tomal es Ba ' and in the 17). Acommon prey is Cal ifornia kill ifish (17) Mudsuckers northern nd o ( th e ul( of California. The northernmost ornge most actively at night (13), and they ",;]1 m ye into ~paw n i n g populations are in Tomal es Ba)', Marin ounty tidall y fI oded marshes to forage at th is time ( 17) . ( ). The ~ opulation now presen t in the Salton Sea and a~ Grm th is r pid in the Salton SC8_ Spring-h'lli..-h .J Ii. h socia ted can als was started with 500 fi sh planted in 1950 by ma y reach 60-80 mm ,md maturity by late August. Gro III , F 1 (5). slows in the winter but by the st art of their ~econd pring most mudsucker, measure 80-120 111m S . They live about Life History Lo ngjaw mud u kt'l"s are not true fres hwa te r 2 year> reachi ng 135-140 mm L (5). Their bC1 sic lie his fish . Th e lo ngest they u~ua lly survive in fres h wate r is 3- 7 tory is simil,1r in ~ uthem Cali fu rnia ~a l l m~11' hes (12) and Javs. evert heless their presence in the Salton Sea, their oc in the sa lt mars hes of San Fral1ci sco Bay ( 15) . The max i casional (if tempora ry) occurrence in low-sal iniLy intertidal mu m siz(:' ms to be about 150111111 TL (4). areas, and their use JS bait fi sh in fresh water, particularly in Breedin~ t ak~ r lacc from December through Jun t' ill the Colorado River, justifies inclusion among the inland San rancisco Bay (although it may occur all year round br fi shes of California. They typically live in shallow, mud th er south) (4) , but it takes place mostly in January-Iulv hottomed tidal sloughs at the upper ends of bays and estu (13). Each femal spawns more than once, usually in re Jries (first-order intertidal creeks) (6). "Vhen the tide is low, sponse to changes in temperature, [ roducing 8,000-27,000 expos ing mud flats, they retreat into burrows or tidal chan eggs ( 1, 14). Breeding usually ceJses during summer, which nels. They can survive temporary stranding on tidal flats is a period of rapid growth and fat storage. Male ll1ud suck and low oxygen levels in their burrows by gulping air ,into a ers construct burrows for hreeding and de fe nd them from highly vascularized chamber in their throat (buccopharyn other muJsuckers. The defense displays in response to an geal chamber) (7). They can also wriggle on their bellies for intruder Jre sp ectacular: the mouth is opened wide and short di ~ { ances across ex posed mud flats to reach water af long maxi llary hones fl are the loose buccopharyugeal skin ter being stranded (8) . outw,ll'd, exposing a larg e:qJdl1Se of reddish, highly vasc u In th e Salron Sea mudsuckers seem to be abundant in larized interior (1 3). onl), a feIV quiet, shallow areas, although they are widely dis Embryos are club shaped and atta ched in clusters to th e trihute I in the sea and have been taken as deep as 12 m (5). side of the burrow by adhesive threads. The male gLtards Thqr can maintain populations in water with salinities as the nest until the young hatch, usually in 10-12 days. Lar high as 82.5 ppt (2) and as low as l2 ppt (9). They can sur vae and juveniles are quite different in appearance from vive temperatures of at least 35°C (5), although they prefer the adults, having short jaws and large eyes. These differ tho~ e within the range 9- 23°C ( 10). Thus mudsuckers can ences are apparently adaptations for surviving the short maintain popLliJtions (including breeding) in turbid salt period they spend li ving pelagi cally, wh ere (hey preSlILl1 evaponltion ponds in San Francisco Bay, where tempera ably feed on zooplankton. Ju ve nil e drop to the bottom at tures range from 6 to 28°C and salinities range from 40 to 8-12 mm TL (4) . 70 ppt over the course of a year (15). In southern California salt marshes their typical fi sh associates are California killi Status IE. Longjaw mudsuckers are common throughout fish, arrow gob)r, and topsmelt (11), whereas in northern their range, although they may be locall)r depleted by col California $,1It ponds they are commonly associated with lecting for use as bait. They are often most abundant in shal topsmclt, yellowfin goby, staghorn sculpin, rainwater killi low, saline environments th at exclude most other fi shes . fish, and threespine stickleback ( 15 ). They have considerable value as bait fi sh because th ey can Longjaw mud~uckers feed on whatever invertebrates and be kept for short periods of time in moist al gJe, are lo ng small fi sh are '1'.'Jilable and their diet changes seasonally de lived on the hook, and will not reproduce in fres h water (1 4). pending on prey availahility (I ). In the Salton Sea adults cat mostly pile worms (NCllIltll1ls) , with lesser amounts of harn,1ci es, aquatic insect larvJe, and fish, including young References I. Barlow 1961a. 2. Barlow 1903.3. Birds lllg ct al. l1111d suckc rs. Large juveniles (25-90 111111 SL) that concen 1988.4. Wang 1986.5. Walker et a!. 196 1. 6. Des mon d et al. Il)l)9. trate in shallow areas feed mostly on brinelly larvae (Ephy 7. Todd and Ebeling 1966. 8. Todd 196::l. 9. Courtois 11.)73. 10. De elm 1, waterboatmen (Corixidac), and pile worms. Small ju \/jami.ng 1971. 11. VVilliam s and 7edlcr 1999. 12. Johnson 1999. vcniles (1 5-25 ITlIll SL) eat copepods, punkyfly larvae 13. \tlleisel1947. 14. Barlow and de ViJm ing 1972.15. Lon%arich (Hclcidae), and free-living nematodes (5). In coastal salt and Smith 1997. 16. llartney and Tumyan 1\J 9R. 17. Wes t and mal'shcs thc)' also eat a wide variety of benthic food, in Zedler 2000. Figure J 45. Yd lnwflo g(,b)" 12 em SL, San Francis 0 e<;[u al·) . UrLllI'ing by . Marci ochi . mea ns yellOlv hand (fin ). Yellowfin go by is not a parti ularly descript ive common name but is a translntion or the Latin name. They are also called oriental gobies and l1Iaha ~.c ("horse goby" in Japanese) dnd are sold in bait stores as "muclsLlckers ." Distribution Yel\owfin gobies are common in shallow coastal waters of Japan, Korea, and hina. The), were first collected in the San Francisco estuary in 1963, where they presumably had become es tablished 3fter being transported across the Pacific in the ballast water of a sh ip (1 ). The), spread ex plosively through the estuary and <.Ire present in the Sacramento River as high as Knights Landing dUel in SJn Francisco Bay. From the Bay they have spread along the coast from Elkhorn Slough to Tomal es Ba)' (2). They ,Ire al so present on occas ion in the Delta-IVlendota Camti, JliCornia Aqueduct, and San Luis Reservoir (Merced Co unty). They were first noticed ill southern Ca lifornia in 19 77, in Los Angeles Harbor, presumably th e res ult of an independent ballast water introduction, and have subsequently bee n found as far south as Sail Diego Bay (3 , 4, 14) . The), still Yellowfin Goby, seem to be spreading, so they ca n be expecte d anywhere Acanthogobius flavimanus (Temminck and Schlegel) along the California coast, especially south ofSan Francisco Bay. Yellowfin gobies have also become established it] ew Identification Yellowfin gobies are elongated (to 30 cm South Wales, Australia (5, 18). TL), blunt-headed fi shes, with pelvic fins united to form a sucke r. There are 8 spines in the first dorsal fin, 14 rays in Life Historv Yellowfin gobies are found in shallow, soft the second dorsal t-ln, 11-12 ra ),s in the anal fin, and 55-65 bottomed areas in fresh, brack ish, and salt water. They are ctenoid . ales in the lateral series. The maxillaries do not ex well adapted for estuarine living beca use they are capable of tend beyo nd the ce nter of tbe eyes, which are closely spaced withstanding abrupt changes between fresh and salt water on top of the head. The color pattern consists of "about and can survive water temperatures greater than 28°C (J). eight di ffus e dusk)' spots, each somewhat larger than the e),e In marshes in San Diego Bay they have been found at sa lin diameter, arranged in a nearly evenly spaced se ries down ities of 16-40 ppt, temperatures of 15- 32°C, and dissolved each side, th e fi rst three being concealed beneath the pec oxygen levels of 3- l4 mg/liter (14). Although they can live torallin, the last forming a mort: prominent spot at the base in fres h W 430 COJ.ltb:; . G H [ [U I\ .. move upstrea m to spawn in brackish water and th n re turn pelagic existence for an undetermined perioJ <)f lime, sel afrer spawning ( 12, 13). tli ng on the bottom at 10-15 mm TL Yellowtl n gob ies take most prey from ambush or by ca re fu ll y ~ ea rch ing the. ubstrate, because th ey swim onl)' 'hort Statu5 UD. Yclk1wn n goby pop ul ations in CiliforniJ h.1W Jistan ccs in a je rk y manner. The sl1la ll est gobi s feed on s read wi del l', ince the fi . b were first noticed TO 19 1. l'h~y co pepod il nd other 5111 (1[1 crustaceans; shrimp, crabs, and are now ont! \)( the most abundant botlllm lishcs in San small fi shes become more im porta nt as the sile of th e fi sh Francisco Gay anJ th e Delta an d are apparentJ\ still in · incr..:ases ( ). In t11e lower Petaluma River, however, cope r asing their range (17). Whal effect this population ex pods arc the princ ipa l fo od of all size cla sses, fo ll owed by ptc ion has h,ld ,1n n: live freshwaler and estuarin..: fis he, is m ) ' ~ id shrimp ,md 3mph ip ods (13). In Suisun Marsh yellow not known. They are d common pn' ) l r pi ci vonlu, bi rd_, tin goh ics of all sizes feed pri marily on Co rophil l1 l1 an d other and fish es and so have clearly entered thl: food VI' ·b. Give n g;l mmarid amphipods (9). Before the collapse of the mysid their cQ mparalive ly large ize and predatory hn hil at'5, they hrimp populations in the (stuM)', opossum shrimp were a could have a negative effect OIl pop ul atio ns of other sma ll major part of their diet 00). benthic estua rine tishc2.s, such as tidewater glib)'. However, Yellowfin go bies apparently only live 3 years, reaching no im pact on stagborn sculpins in Newpllrt Bay was dc 10-14 cm SL at the end of their first yeM, 16-18 cm at the tec ted (I S). Fortuniltel), tl1<2)' seem to have a h,l rd tim e s end of their second year, and J.7 cm or more at the end of tabli shin g themselves in coasta l lagoo ns that dose mtl t of" th eir third yea r (6, II, 13 ). A goby that measured 22 cm SL the year. During 1995 th ousdnds of yo ung-of-year invaded (27 cm TL) was over 3 yea rs old ( 13 ). Males usually become the large lagoon at th e mouth of the Santa Margarita RiYer, m Ergs are teardrop shaped and attached by adhesive fila Haakcr 1979.4. Swi fl et al. 19'13. 5. lYli dd leton 19H2. 1. Britlan et ments to the roof of the burrow in a single layer by the fe al. 1970.7. "Vang 1986. S. Kikuchi and Ya mashita 1992.9. r:cy rer male. They are then fertilized by the male. Embryos are 1999. 10. Herbold 19R 7. 1I. Hoshino et al. J9(1). 12. Oo tsu alld f'. uarded by the male until the), hatch (28 days at l3°C), but Mito 1955. 13. Baker 1976. 14. Williams et al. 199R. 15. Ursu i <1PI) Shimofuri Goby. Tridentiger bifasciatus Steindacher goby). In living fish colors are va ria ble and changin::: , hut most fish have tiny white speckles on the head that ex tcnd Iden tification Shimofuri go bi es are small (usuall y <85 mm onto the ventral surface; edges of the second dorsa l and anal SL) and StOllt with blunt, somewhat flattened heads , thick fins that are fringed with orange and without handin g; ti ll l' c llIclal pedllncles, small eyes close to th e top of the head, spots, more or Ies in rows covering the tail; a distinct stripe al1d rounded tails. [n adults th e maxilla ex tends nearly to the ru nn ing along the top of each side, from the top of the head bJck of the eye. The flat region between the eyes on top of to the base of the tail ; and usually a di stin ct dark band along Ih e hl' ... I! I . I 0 F L' It I (, l ) B' 11: Figure 146. Shimofuri goby. 'Iup: Male, 7 cm SL. Suisun Marsh, Sola no CouIlt)'.llottom: Female, 6 cm SL, Suisun ivlarsh, Solnno 4cm Count y. outside row in the m o uth, which have three ClISPS, while bi fasciatu s means two-striped. Distribution Shi lllofuri goby are native to est ua ries of japan and mainland countries along the Sea of japan. They w re introduced into California, undoubtedly carried in the bal las t water ofa ship, sometime shortly before 1985, when the species was first collccted in Suisun Marsh (4) , It quickly became one of thc Illost abundant fish in the upper San Francisco F:;Luary. By 1990 it was es tabli shed in Pyramid Rese rvoir, some 513 km from the estuary via the Ca li fo rnia Aqueduct. In 1992 it wa s found in Pim Creek, below th e reservoir (4). It ca n be expected in any rese rvoi r fed by by later-Emperor Akihito and K. Sakamoto of Japan (2). water from the Ca lifornia Aqueduct and in the streams and Biochemica l studies confirmed its distinctness (3). T estuaries below them, trigullocep/w/us, the chameleon goby, was found in Los An geles harbor in 1960 and San Francisco Bay in 1962; it has Life History Because of taxonomic confusion, shimofuri become common in the Bay (4). It was therefore assumed gobies have been little studied in their native habi tots. that the first specim ens of the shimofuri goby (collected in Therefore most of what we know about this species comes 1985) were chameleon gobies, even though they were found from the study by Matern (5, 10) of the population that has in fresh and brackish water, whereas the chameleon goby is invaded the San Fransciso Es tuary. Shimofuri gobies a re a m arine species. Reexamination of fish from both envi widdy distributed in tidal habitats in the estuary, hut prefer ro nments demonstrated that tIte fresh and brackish water shallow-water «2111) areas wit h comple,' structur - w cks, forms were indeed shimofu ri gobies (4 ). logs, lule root m asses-which [hey li se fo r COl' 'r dnd breed ing. T hey have been ob 'erved in shallO\ pools J. t low ti de Nam e T he japanese co mmon name of this goby is "shi with te mperatures a high , s 34°C thdt we re ai' . ubjecteJ m ofuri -himahaze" (2). 'h imahaze means striped gobI', a to rapid temperature change, as the tide rose ,md felL In th e name al ready in u e in English. Shimofuri refers to beef laboratory they can tolerate temperature' up to 37° (5, marble I w ith \vhite Cat M l d describes the pattern of tiny 10). T h y are less tolerant of high salinities. In the estuary wb ile spots U ll the head, so it wa, chosen as the common tbe gobies have been collected in water w ith sJl in iti 's ,,' name ill E.nglish (4-) . Tri-del/ tigcr refers to the teeth ill tbe high as 19 ppt, but in the bborat ry the, show extreme dis .J.38 C; 0 B r E ~ . G l) 1:\ r iD A E lre -s when sali nities approach [7 ppl (10). T'hc~) readilr live peralures (I3-34oq and salilllties (0-7 ppt . Each nest pr..: an hre ed in fre h water, ho wever. resulti ng in populations -umably produces a steady strt.'am of larvae SWimming up bei ng established in reservoi rs. into the water co lu mn th roughout the summer r until the Shimofuri gabies apparenrl y di sper e mainl, during lar male is dead of exhaustion. Any abandoned nest is qui kl) I'al anu early juvenile ~tages , because adults appear to be re('lccupied. however. because su it able nesting cavil ies seem f:l irly sedentJ l')'. Ad ul ts J re quite aggressive to other mem to be tn shon suppl) in the estuary. be rs of the same species, La other benthic ti shes (especially Larvae are pel.tgi and are the sm aJ le~t 6_h larYJe in the other species f gobics) , and to smaU cra bs (5). r-.1u h of this tuary. They are often th e most ab undant fish I.lr\'a~ in Ihe t: he havi r i. related to de(c: nse af rocks and other shel ters that tuary. p >aklng in abundance in June when the water warms are suitab le lor hreeding and refuge fro m predators . In up. alth ug h the peak may oc ur earli er in dry years (lIl. aquaria they will drive smaller tid el·vater gobies from shel Th )' seem to beco me widely d ' ~tri b llt' d through ti dal t rs and m3Y occas ionally devour individuals that do not re currents. treat, such as female tidewater gobies trying to court la rge male shimofuri gobies (5) . Statu UE. The shimofuri gob)' is another one of lifor The go bies' observed modes of feeding are "sideways nia's explosive invaders, beco mi ng abundant and wi lely substrate bites" and "midwater ca pture," typical of gobies di stributed in less than 10 yea rs. It ra nge in the stJ k i ~ still' that rel y on vi sio n for prey capture (5,6). Biting the sub expanding as it moves through aqueducts to new wate rs. strate whil e turning the head sideways is presumably the Its success ca n be attributed to a number of factors acting most common mode of feeding, based on stomach con simultaneousl),: tents, beca us e they fced entirely on benthic prey, including attached organisms. They have been found to fe ed heavil y 1. It has a high dispersal ability, mainly throug h larvae, on attached hydroids (Co l'),dylophora caspia ), the cirri which enables it to be carried by ships across the (exposed tentacles) of barnacles (Bnlm1lls iIJIPl'ovislI') , and ocean and by aqueducts to distant r e~e rvllirs. tube-dwelling amphipods (Corophium spp. ). Their tin y, 2. It is tolerant of a wide range of envi ron mental co n tricuspid teeth may be ~n adaptJtion for graz ing on such ditions, more so than many resident species, 440 GOB I E S. GOB II D A E Mullets, Mugilidae Mullets an: primarily tropical and temperate marine nshes, wh erever they are abundant. Only the striped mullet enters but l11any species move readily into fresh and brackish fresh water in Ca lifornia, although a similar species, the water. Their Jistribution is worldwide. Because they school white mullet (Mugil ClIrema), is occasionaLly found in in shallow water and estuaries, feeding largely on detritus marine waters (Lea et al. 1988). they stir up from the bottom, they are popular food fish long with a large gizzarJ, and gill fakers arc 1011" and slen der. The backs o[li ingflsh are blue-green, dnd the sides and belly are silvery with narrow, horizontal black strip es on the upper half of the body. Taxonomy Despite a worldwide di stribution, striped mul let are definable as one species, with relatively small gen etic and meristic differences among populations in different ar eas, compared with djfference among species of M/lgil. "However, the considerable genetic differentiation aillong populations, in conjunction with the extremely reduced, llr nonexistent, current gene flow, suggests that at least some of Striped Mullet, Mugil cephalus Linnaeus them are at the stage of incipient speciation" (14, p. 217). Idf'IJUric,7 tion Striped mullet have thick, torpedo-shaped Names Striped mullet are known as gray mullet or sea mul bodies; broad , f"lat heads; small terminall11outh s; large eyes let in much of the English-speaking world outside North (width grc:ater than length of snout); deeply forked tails; America. Mugil is derived from the Latin verb meaning "to widel), separated spin)' and soft dorsal fins; and translucent suck," referring to their feeding habits; (cphl1ll1s is appar adipose eyelids that nearly cover the eyes, leaving only a nar ently derived from the Greek word for head , although the row slit over the pupil. The maxillary is hidden when the ancient Roman word for mullet wa s ceJollls. mouth is closeJ, giving the mouth an in verted V shape from a he,ld-on vi ew. There are 4 spines in the first dorsal fin and Distribution Striped mullet inhabit tropical and subtrop i 1 spine and 8 ra ), s in the second. Adults have :I spines and cal coastal area s around the world, includi ng oceanic is il- 9 r,lVS in th e anal fin , while juveniles (50 mm TL) have 2 lands. Adults are found al ong the alifornia coast north as . pin es :1J1d il- 9 rays. The pectoral fin has 16-17 rays, and the far as San Francisco Bay (dming El Nino years), although la lcrallin e bas Jil- 42 cycloid scales. In fis h smaller than 50 the)' are rare north of Point Concep tio n. They arc some 111 111 TL the adi pose ey lid is not evident. The int es tine is limes among the most abundan t fi sh in 't uari es in the Sa n III Figure 147. SU'i ped l11ulld. lY cm SL, Mexico. Drawing br A. iV[arciLl(hi. Diego region. Young-of-year striped mullet are found in ter, presumably because its ionic composition was different lower reaches of larger streams from the Santa Clara River (5) . Large populations that once existed there were re (Ventura County) south, although in warmer years they cruited from young muller moving up canals from the Col may be found as far north as Shuman Lagoon, Santa Bar orado River or by spawning in the Alamo River or other bara County (13). They have been found as far as 35 km up tributaries. Wh en th e canal system was altered, making ac stream from the mouth of the Los Angeles River (I) and are cess to the sea more difficult, mullet gradually becam > rare, present in the lower Colorado River from its mouth to Im with the population maintained by oc«} ional spawnin o in perial Dam, about 190 km upstream. They were once the the Al amo River. Howeve r, some spawning in Life sea may most abundant fish in the Salton Sea but are now rare there; have taken place ea rlier in its histury when salinities were small numbers are apparently present at the mouth of the lower (6). Alamo River (l 0). They were present in prehistoric fillings The ability of young-of-year mullet to move upstrt'dm of the sea as well (2) . from estuaries may account for their abundance at times in southern California streams such as San Juan Crc "k or the Life Historv Striped mullet have been well studied because Santa Margarita River (12), although spawning by adults of their worldwide distribution and importance as food cannot be completely discounted. In the San La tV'largari ta es fish. However, little work on them has been done in Cali tuary, juvenile mullet that measured 2-3 em TL in Janu old (29-46 (Ill SL) (4). However, postlarval mullet (2 -40 fe ed on bits of algae t10ating cl ose to tl1e wat er : LlI fa (6 l. mm L), tou weak to swim upstream, have been found In the Colorado River their diet is mai nly detritus but in nearly 200 km from the mouth, indicating th<1t sOllle fres h cludes small amounts of aquaLi c insects ~8) . !vlost feeding \ ',H er SP J\ 'n ing occu rs (4) . takes pIa e durin g the da)! (9) . Mullet were unable to spawn in the S:Iilon Sea in the Age and growth in striped mullet are hig hly va riabk. In 19 505, even tbough ito sa lin it)' was close to that of sea wa the lower Colorad River fish measuring 7- 13 cm SL are ap 44 2 1\ I U L L. E T S. wi U GIL I DA 1: parenti}' apprc1ach ing 1 year old; those 17- 20 em SL are 1-2 li kely lilal number<; olTt' lower. ~ma ll populat ion seem tel years old ; those 2 l-28 em SL, 2 Y at's old; and those 29-37 bave persisted in the , alton Sea as well (10). hey are of mi em Sl, 5 yea rs old (4). The oldest and la rges t mull et Ilor importance as sport fish because they can bt: take n only kn own were (ro m the largely nonreproducing Salt n Sea on sma ll bai ted hooks on the bottom or with small tlie' (11). P< pu lat ip ni a fema le measuring 62 cm . L and a mal e meas They supported a commercial (j~her)' in the alton ea from uring 6() cm SL were proba bl y at least 14 years old (5 ). 1ul 19 15 to 1921 and again from 1943 to 1953, when it was for I t IIs uall y become mature at 2-3 yea rs of age (23- 35 em bidJen in favor of the sport fis her)' ti r tht:!" ,peeie . f ~m~1f L). lost fi sh over 25- 0 cm SL are females. commcrciil l fishery still exists in San Diego Bay (I I ), a~ J es an lilegal cast net fish ry ( 13). Their r Ie in ~()ulhcrn (.al l Status IF. Striped mu ll et how nuclualing abundance in fOrnia strea I1lS and estuaries has n(lt been investigated. Ca liforn ia's inland waters because they are a subtropical to tropica l species at th e northern end of their I·ilnge.ln coastal Refer nces I. Swift et aJ. ]993.2. Gobalcl 1992. 3. Th om ~o n southern California they appear to be permanent residents 1963. 4. Johnson and McC lendon J 970. 5. Hendri cks 196 1. 6. Dill in San Diego Bay and occur in most years in the lower San 1944. 7. dum 1% 8. 8. Min ckley 1982. 9. oHins 198 1. J O. S. Marga rita Ri ver, Malibu Lagoon. Newport Bay, and similar Keene)" DFG, pers. Co 111111. 1999. II. Lea et aJ. 1988. 12. R. areas (13). They are still present in the lower Colorado River Fisher, per~ . comm. 1998 .13. C. C. Swi ft, pers. l·Oll1 m. 1999.14. despite dcteriorati n of water f1 wand qua lity, although it is Ross i et al. 1998. <; T 11. 11' E [) 1'-1 L 1 LEI H}