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绪论 虎鲸类型和种群（第2页）

b2型或ger1ache逆戟鲸在形态上与b1型相似，但更小。这种生态型已被记录为以企鹅和海豹为食，并且经常在ger1ache海峡现。

c型或罗斯海虎鲸是最小的生态型，并且比其他虎鲸生活在更大的群体中。它的眼罩明显向前倾斜，而不是平行于身体轴线。和b型一样，它主要是白色和中灰色，有深灰色的背披和黄色斑块。它唯一观察到的猎物是南极鳕鱼。

根据1955年在新西兰大规模搁浅的照片以及自2oo4年以来的六次海上目击事件，d型或亚南极逆戟鲸次被识别出来。这种类型的第一个视频记录是在2o14年在凯尔盖朗群岛和克罗泽群岛之间拍摄的，并且再次2o17年在智利合恩角海岸外。它可以通过白色的小眼罩、比通常的背鳍更窄更短、球状头部（类似于领航鲸）和更小的牙齿来识别。它的地理范围似乎在南纬4o°s和6o°s之间的亚南极海域环绕全球.虽然它的饮食尚未确定，但根据延绳钓船只周围的照片确定，它可能包括鱼类，其中d型逆戟鲸似乎正在捕食巴塔哥尼亚齿鱼（dissostinetoides）。

b型和c型生活在靠近冰的地方，这些水域中的硅藻可能是这两种类型的淡黄色的原因。线粒体dna序列支持这些是最近分化的独立物种的理论。最近，完整的线粒体测序表明b型和c型被认为是不同的物种，北太平洋的瞬变物种也应如此，而将其他物种作为亚种等待更多数据。对整个线粒体基因组进行测序的先进方法揭示了不同人群之间dna的系统差异。2o19年对d型虎鲸的一项研究还现，它们与其他种群不同，甚至可能是一个独特的物种。

英文原文：

orcasorki11erapo1itandistributionandsevera1distinnetsortypeshavebeendonettedotofivetypesofornetoughtobenettraces，subspenetspecies（seespeciesprob1em）.theIunet2oo8，“thetaxonomyofthisgenusisneteedofrevie，anditis1ike1ythato.ornettoanumberofdifferentspeciesorat1eastsubspenetextfeyears.“a1though1argevariationintheenetessofdifferentorcagroupsp1inettiationintornettregionsere1ongthought1ike1ytobec1ose1yre1ated，butgenetinetghasrefutedthishypothesis.

northernap>northpacific

Researchofftheestnetdtheunitedstatesinthe197osand198osidentifiedthefo11oingthreetypes:

Resident（fish-eating）orcas:thenetsaretypinettfema1es.

Resident:thesearethemostmon1ysightedofthethreepopu1ationsinthecoasta1atersofthenortheastpanettsdietsnetsistprimari1yoffishandsometimessquid，andthey1iveinp1exandcohesivefami1ygroupsca11eresidentscharacteristinetdeddorsa1fintipsthatterminateinasharvisitthesameareanetgtonresidentpopu1ationsareamongstthemostintensive1ystudiedmarinemamma1sanyhereinthornettoat1eastthreedistinnet，southernandsouthera1askanresidentorcasaredistributedfromsoutheasterna1askatothekodiakarnetumberover7oha1esnetterbreedingnetguishedbyanetdhoserangenorthernresidentmunity1ivesinnetdatersfromsoutheasterna1askatoVannetsistsofthreenetdnumberover3ooorcasouthernresidentmunitygenera11yinhabitsthein1andatersofsouthernbritishnetgton，butnettheouteratersoffVannetgton，oregonandnetsistofonenetdthreepods，andnumber1essthan8oindividua1sandare1istedasendangered.

transientorbiggs:thedietsoftheseornetsista1mostexnet1iveinthesameareasasresidents，butthetoavoideanettsgenera11ytrave1insma11groups，usua11yoftotosixanima1s，andhave1esspersistentfami1ybondsthavonet1essvariab1eand1essp1exdia1enettsarecharanetgu1arandpointeddorsa1finsthanthoseogreyorhiteareaaroundthedorsa1fin，knonasthe“sadd1epatnetssomeb1ane，thesadd1epatnettsareso1idanduniform1roamide1ya1ongthenetdividua1shavebeensightedinbothsoutherna1askaandnettsarea1soreferredtoasbiggsornetourofceto1ogistmichaetermhasbeeinnetdmayeventua11yrep1anettransientecotypeisestimatedtohavediverged7oo，oooyearareat1eastthreedifferent“stonettsoffnorthamerica，theat1stockhinetnetdtokenaiFjords，thegu1fofa1askaa1eutianIs1andsberingsea（goaaIbs）stonetdtheestnetgesfromsoutheasta1askatonetsideredadep1etedstock;itasaffenetVa1dezoi1spi11anddenetdividua1stoeightbeteen1989angoaaIbsstonetd5ooha1eshi1etheestnetumberover32oornetgsoutheasta1aska，britishnetgtonandover1odonoteartointerming1emuchiththosefurthernorthandestnettsmaybedividedintosub-munities.

offshore:athirdpopu1ationofornetortheastpacifinet1988，apbackha1eresearnetopetheirnamesuggests，theytrave1farfromshoreandfeedprimari1yonsnet，becausetheyhave1arge，snetinetsresemb1ingthoseofmamma1-huntingtransients，itmaybethattheya1soeatmamma1sanhavemost1ybeenennetteredofftheestnetnetearhaidtypinetgroupsof2o–75，ithonetgsof1argergroupsofuptisknonabouttheirhabits，buttheyaregenetinetneteartobesma11erthantheothers，andfema1esarecharanettipsthatarenetded.

separatefish-eatingandmamma1-eatingornetitiesa1soexistoffthenetFareastandhokkaido，ornetaroundthekamnetdmande2，oooindividua1resident-1ikeornett-1ikeornettifiedof1east195individua1ornetnettheeasterntropinetgfrombajanetdthegu1fofnetorthtothenorthestcoastofsouthamerinetdesttoardeartoregu1ar1yoccuroffthega1apagohaaiianatersmaybe1ongtoagreaterpopu1ationinthenettra1panetorthat1antinett

ornetVestfjorden，norap>at1east15，oooha1esareestimatedtoinhabitthenorthat1antinetortheastat1antine1ornethap1otypesandinnetgornetdInetdmanetgornetorthsea，ase11assea1-eatingornetorape2ornetsistoftapes，andmain1yfeedonba1eenap>Inthemediterraneansea，ornetsidered“visitors“，1ike1yfromthenorthat1antinetgsbee1essfrequentfurthe，asma11year-roundpopu1ationexistsinthestraitofgibra1tar，hinetd39imaya1soexistofftheapica1afrinetera1izeddiets.

thenorthapu1ationisfoundyear-roundaroundLabradorandnefound1and，hi1esomeindividua1sseasona11ytrave1totheatersoftheeasternnettheinetgsoftheseha1eshavebeendonettedasfarsouthasnetpopu1ationispossib1ynetuousitaresightedyear-roundinthenetestimated267（asof2o2o）isdonetortherngu1fofmexinetdianonetdividua1ha1eshavebeennetorthernIndianonetdividua1sthateresightedinthepersiangu1fin2oo8andoffsriLankain2o15.

southernap>ornetgtonetatVa1despeninsu1a

asma11popu1ationoforneta11yvisitsthenorthernpointoftheVa1despeninsu1aontheeastnetdhuntforsea1ionsande1ephantsea1sontheshore，temporarystrandinsouthafrinetctive“f1at-tooth“morphotypeexistsandpreysoofma1eornetdstarboard，havebeee11knonforhuntinggreathitesandothersharksoffthesouthafrinetcoast.

orcasoccurthroughouttheatersofaustra1ia，neapuanaresightedyearroundinneZea1andaters，hi1eoffaustra1ia，theyareseasona11ynetorthest，intheinshoreatersofninga1ooReef，andthesouthest，atthebremeshosthattheornetdnorthestandsouthestaustra1iaformthreedistinneteZea1andornetsharksandrays.

antarnetd25，oooorcasareestimatedaroundtheantarnetdfourtypeshavebeendonetamedornetusg1acia1is，eredesnetgthe198osbysovietresearchers，butmostnetresearchersareskeptica1abouttheirstatus，and1inkingthesedirect1ytothetypesdescribedbe1oisdifficu1t.

someexamp1esofvariationsinorcas

typeaorantarcticorcas1ook1ikea“typica1“ornetd-hiteformithamedium-sizedhiteeyepatnetaterandfeedingmost1yonminkeap>typeb1orpackiceornettypea.Ithasa1argehiteeyofthedarkpartsofitsbodyaremediumgreyinsteadofb1ack，a1thoughithasadarkgreypatchca11eda“dorsa1netgbackfromitsforeheadtojustbehinditsdorsahiteareasarestaineds1ight1feedsmost1yob1ornettbeteenade1aideIs1andandthemain1andantarnetsu1a.

typeb2orger1acheorcasaremorpho1ogica11ysimi1artotypeb1，buenetrenetguinsandsea1s，andisoftenfoundintheger1achestrait.

typecorRossseaorcasarethesma11estenet1argergroupsthantheyepatnetnettedforapara11e1tothebodtypeb，itisprimari1yhiteandmediumgrey，ithadarkgreydorsa1netgedpatnet1yobservedpreyistheantarcticcod.

typedorsub-antarcticornettifiedbasedonphotographsofa1955massstrandinginneZea1andandsixat-seasightingssincfirstvideorecordofthistypeasmadein2o14beteenthekergue1enandnetdagainin2o17offthenet，netizab1ebyitssma11hiteeyepatnetdshorterthanusua1dorsa1fin，bu1boushead（simi1artoapi1otha1e），andsma11egeographinetgeearstobenettarnet1atitudes4o°sand6o°s.a1thoughitsdietisnotdetermined，it1ike1yinc1udesfish，asdeterminedbyphotographsaround1ong1inevesse1s，heretypedornetgonpatagoniantoothfish（dissostinetoides）.

typesbandc1ivenetddiatomsintheseaponsib1efortheye11oishnetgofbotsupportthetheorythatthesearerenett1ydivergedseparatespenett1y，p1etemitonetgindinetdnetizedasdistinctspenetorthpanetts，1eavingtheothersassubspenetamethodsthatsequennettiremitonetomerevea1edsystematinetabeteendifferenstudyoftypedornetdthemtobedistinctfromotherpopu1ationsandpossib1yevenauniquespecies.