Introduced Species in the Estuary, Part 3
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Introduced Species Page 78 apparentpattern of spreadin 1978-79,that thesite of introductionwas in the Pittsburg-Antiocharea near where S. doerrii was first collected.They further suggest that waterpumped out of the Deltainto the CaliforniaAqueduct will carryS. doerrii to waterproject reservoirs near Los Angeles, and that theColumbia River and Puget Soundare likely sitesfor secondaryintroductions via the ballastwater carried by coastal ships. Several researchers have considered interactions between Sinocalanus doerrii and other copepodsin the northernestuary someof which are discussedabove under PseudodiaptomusIorbesi!. Orsi et al. 983! noted that competition between Sinocalanusand the cryptogenic copepod EurytemoraafPnis was unlikely because their preferredsalinity rangesdiffered, and suggestedthat competitionand/or predationbetween Sinocalanus and the freshwatercopepods Cyclops and Diaptomuswas a stronger possibility and should be investigated. Ambler et al. 985! questionedwhether there is competitionfor food, at leastin yearswith average river dischargeand diatom blooms in Suisun Bay. Meng & Orsi 991! found that striped basslarvae in laboratory feeding experimentsselected Cyclops sp. and Euryfemora over Sirtocalartus. Herbold et al, 992! reported that the introduction of Sinocalanusand of Pseudodiaptomusforbesi in 1987 was followed by declines in Euryfemora and the almost complete elimination of Diaptomusspp., although Herbold & Moyle 989! had earlier suggestedthat declines in Delta zooplankton prior to 1979may have facilitated Sinocalartus'establishment. Kimmerer 991! reported laboratory studies indicating that although Sinocalartusmay be food limited in the estuary in some years, Eurytemorais not and so competition with recently introduced copepods could not account for Eurytemora'sdecline. Orsi 995! suggestedthat Sirtocalanus had "apparently slipped into an unoccupied niche" between Euryfemora downstream and Diaptomus speciesupstream in the San Joaquin River, but noted that Diaptomus abundance fell when Sirtocalanusspread upstream. Herbold k Moyle 989! had noted that the invasion of the SacramentoRiver by Sirtocalanus coincided with a reduction in the relative abundanceof chlorophyll in the north Delta. Tor tan us sp. This large calanoid copepod of unknown origin was collected in Suisun Bay in the fall of 1993and in 1994 Orsi, 1994,1995; J. Orsi, pers. comm., 1995!.It preys on other copepodsand Orsi 995! suggeststhat it may have causeda decline in Pseudodiaptomusin western Suisun Bay in 1994.Its prior absencein this well- studied region of the Bay suggeststhat it was introduced in ballast water. fntroduced Species Page79 Qg~ Balanusamphitrife Darwin, 1854 STRIPED BARNACLE SYNONYMS:Bafanus amphifrife amphitrife Darwin, 1854 Balanus amphitrife hawaiiensis Broch, 1922 Balanus amphifrife denficufafa Broch, 1927 Balanus amphitrife her@iRogers, 1949 Balanus amphitrifefranciscanus Rogers, 1949 Balanus amphifrife salfonensisRogers, 1949 Thissubtropical and warm-temperate barnacle is nativeto the Indian Ocean but hasbeen distributed widely. In perhapsthe earliest scientific recognition of the phenomenonof marine introductions, Darwin 854, pp, 162-163! noted that Balanusamphitrife, B. improvisusand a fewother barnacles "which seem to range overnearly the whole world excepting the colder seas!" may have been transported to partsof theirreported range as foulingon ships. B.amphifrife was collected in Hawaiiin the early1900s. In Californiait was foundin La Jollain 1921,in SanDiego in 1927,in SanFrancisco Bay in 1938-39,and in theLos Angeles/Long Beach area in 1940 Zullo et al., 1972; Carlton, 1979a, p. 585!. In 1945it was found in the SaltonSea, probably introduced from SanDiego Bay attachedto "navyplanes, boats, buoys, ropes, or othermarine equipment that was transferredin large quantity to thesea for training purposes" Carlton, 1979a!. It was first collected from the Gulf of California and the west coast of Mexico in 1946,and appearedon theAtlantic coast of NorthAmerica after World War Il, AlthoughBalanus amphi rifetolerates water temperatures down to 12'Cit requiresat least18'C to breed. It maythus be restricted to warmersites within San FranciscoBay, where it hasbeen collected from scatteredlocations in the northern SouthBay, Central Bay and San Pablo Bay Newman,1967!. In Britainand the Netherlandsit livesin areasheated by the outflow from power plants Vaas,1978; Carlton, 1979a!. Balanus improvisus Darwin, 1854 BAY BARNACLE Balanusimprovisus, a nativeof the North Atlantic,is themost freshwater- tolerantof thebarnacles and has been widely introduced around the world. It is also the earliestknown introduction to SanFrancisco Bay, having been identified from a musselshell in U. C, Berkeley'sMuseum of Paleontologythat wascollected from the harborof SanFrancisco in 1853 Carltonk Zullo, 1969!.This early introduction wasprobably the resultof transportas fouling on ship hulls. B. improvisusis nextknown in SanFrancisco Bay from specimenson the shellof an Atlanticoyster, Crassostrea virginica, collected at SanMateo in 1900,and introduced Species Page80 thebarnacle then appears in collectionsfrom every decade of the twentiethcentury, oftenon oysteror musselshells Carlton k Zullo,1969!. A secondintroduction and possiblyadditional introductions! of B.improvisus, with shipmentsof Atlantic oystersthat began in 1869thus seems possible. It is notknown whether the 1850s population,introduced by shipping,persisted or diedout. B. improvisuswas collected from MontereyBay in 1916,from the Los Angeles/LongBeach area in 1932,and from San Simeon Point and San Diego in 1939.Despite these records from the 1930s, B. improvisus does not appear to be established in southern California. There are other reports from the tropical or subtropicalPacific, though actual collections are few: the Gulf of CaliforniairL 1889, 1941and 1967;the west coast of Mexico in 1960-1968;Colombia in 1854;Ecuador in 18S4,1934, 1963 and 1966;and Peruin 1926.The identificationof someof these populationsas Balanusimprovisus may bearreexamination. B itnprovisusis likely establishedin baysto the north of SanFrancisco Bay, perhapsin somefrom whichit hasnot yet beenreported. It wascollected from VancouverIsland and Willapa Bay in 1955,from the ColumbiaRiver in 1957 on the shell of the crayfishPacifastacus trorvbridgii!, and from CoosBay in 1978.Since World War II, it has alsobeen reported from Japan,Singapore and Australia Carlton, 1979a!. In SanFrancisco Bay its physiologyand behavior were investigated by Newman 967! who found that it tolerated dilution to 3 percent seawater,and that, surprisingly,it wasan osmo-conformerwith its bloodremaining nearly isotonic with its environment.It is the only barnaclefound upstreamof CarquinezStrait in the northernpart of theestuary. At Antiochit livesin freshwaterfor ten monthsof the year.A populationwas found in December1962 living on the concretewalls of the Delta Mendota Canal in essentially fresh water, although there is no evidence that barnaclesin the canal reproduce successfully Zullo et al., 1972!. F.pjneba1iasp, This unidentified nebaliid was collected on muddy bottom by John Chapman in Aquatic Park Lagoonin Berkeleyin 1992,and we found it commonat Richmond in 1993and Lake Merritt in 1993and 1994.G. Gillingham pers. comm., 1995! reports "Nebalia pugettensis"collected at the Alameda Naval Air Station in the spring of 1993.The prior absenceof reportsof any nebaliidfrom SanFrancisco Bay, and specifically the absenceof a nebaliid from the East Bay shore in the 1960s-1970s, suggeststhat all thesespecimens are an introducednebaliid rather than the native N. pugettensis.Although largely benthicorganisms, nebaliids could easilybe transported by baHastwater in suspendedsediments swept up from the bottom while the ship is baHasting. Introduced Species Page81 hlyadam Acanthomysisaspera li, 1964 Thisplanktonic Japanese mysid was found in the northernpart of the San FranciscoEstuary in 1992and was still present,though not abundantin 1993-94.It wasprobably introduced inballast water T. W. Bowman, in litt. to J.J. Orsi; Orsi, 1994, 1995!. Acanthomysis sp. An undescribedspecies of Acanthomysis,resembling A. sirtertsis T. W. Bowman,in litt, 23Mar. 1994to J. J. Orisi!, was collectedin SuisunBay in 1992,and was more abundant than the common native opossum shrimp Neomysis mercedis by 1994Q. Orsi, pers. comm., 1995!. Because its morphologyresembles that of westernPacific mysids and is unlikethat of easternPacific species, it is probably nativeto the westernPacific and was transportedto Califorruain ballastwater Orsi, 1994; T. W. Bowman, in litt.!. Deltamysisholmqttistae Bowman & Orsi, 1992 Deltamysishoimqttistae was first collected and described from the San FranciscoEstuary in 1977.Bowman & Orsi992! reportthat it hasbeen collected everyyear since, ranging from one specimen in 1984to 39in 1987.Most were collectedfrom Carquinez Strait to theDelta, with onetaken in SanPablo Bay during thehigh spring outflow of 1983.They were found mainly in salinitiesof '1-2ppt at theupstream edge of theentrapment zone, but rangedfrom 0-19 ppt. Deltamysisis in the tribe Heteromysinialong with mysidsthat are commensalor epibenthic,or that swimamong sea grass plants, and this could accountfor the small numbersof Deltamysiscollected in openwater trawls. That Deltanrysiswas not collected until 1977despite sampling for rnysidssince 1963, and thatit hasbeen collected regularly if sparselysince 1977, strongly suggests that it is introduced,probably in ballastwater, There are no known