Abadla inetha ngamagama oshaka bakasilika abadobi empumalanga yePacific Ocean. Izilwane ezizingelayo zizingela i-tuna ngonya kangangokuthi zibhoboza kalula ukudoba.
Incazelo kasilika kashaka
Lolu hlobo, olwaziwa nangokuthi yiFlorida, usilika oshubile nomlomo obanzi, lwethulwa emhlabeni ngososayensi bezinto eziphilayo baseJalimane uJacob Henle noJohann Müller ngo-1839. Banika lezi zinhlobo igama lesiLatini elithi Carcharias falciformis, lapho i-falciformis isho isikela, ikhumbula ukumiswa kwamaphiko we-pectoral ne-dorsal.
Izinhlanzi ze-epithet "kasilika" zathola ngenxa yesikhumba sayo esibushelelezi ngokumangazayo (ngokumelene nesizinda sabanye oshaka), esibuso baso sakhiwa izikali ezincane ze-placoid. Mincane kakhulu kangangoba ibonakala - ayikho nhlobo, ikakhulukazi uma ibheka ushaka obhukuda elangeni, lapho umzimba wayo ucwebezela ngemibala e-silvery-grey.
Ukubukeka, ubukhulu
Ushaka kasilika unomzimba omncane ohlelekile onempumulo eyindilinga eyindilinga, enesikhumba esingaqapheleki ngaphambili... Amehlo ajikelezayo, aphakathi nendawo afakelwe ulwelwesi olucwayizayo. Ubude obujwayelekile boshaka bakasilika bukhawulelwe ku-2,5 m, futhi ama-specimens angavamile kuphela akhula afike ku-3.5 m futhi anesisindo esingaba amathani ayi-0.35. Emakhoneni omlomo omise okwe-rhengi, kukhonjiswa imisele emifushane engajulile. Amazinyo acijwe kakhulu omhlathi ongaphezulu abonakala ngesimo esingunxantathu nokuhleleka okukhethekile: maphakathi nomhlathi, zikhula ziqonde, kepha zincike emakhoneni. Amazinyo omhlathi ongezansi abushelelezi, amancane futhi aqondile.
Ushaka kashaka unamabhangqa ama-5 ama-gill slits anobude obumaphakathi kanye nomphetho ophakeme kakhulu we-caudal onekhala eliphansi elishiwoyo. Ukuphela kwe-lobe engenhla kungaphansi kancane kokuphela kwesiphetho sokuqala se-dorsal. Yonke imiphetho ye-sickle shark (ngaphandle kweyokuqala ye-dorsal) imnyama kancane emaphethelweni, okubonakala kakhulu ezilwaneni ezisencane. Ubuso besikhumba buhlanganiswe kakhulu nezikali ze-placoid, ngayinye ephinda ukwakheka kwe-rhombus futhi inikezwe umgogodla onezinyo ekugcineni.
Umhlane uvamise ukudwetshwa ngothoni omnyama grey noma onsundu ngegolide, isisu simhlophe, imivimbo elula iyabonakala ezinhlangothini. Ngemuva kokushona kukashaka, umzimba wayo ulahlekelwa masinyane njenge-silverycent iridescent futhi ufiphele ube mpunga.
Uhlamvu nendlela yokuphila
Oshaka bosilika bathanda ulwandle oluvulekile... Bayasebenza, banelukuluku futhi banolaka, yize bengeke bancintisane nesinye isilwane esidla inyama esihlala eduze - ushaka onamandla futhi ohamba kancane onamaphiko. Oshaka besilky bavame ukugcwala ezikoleni, ezakhiwe ngosayizi noma ngobulili (njengasePacific Ocean). Ngezikhathi ezithile, oshaka bahlela ukuqaqa okungaphakathi, bavule imilomo yabo, baphendukele eceleni babhekane futhi baveze imiphunga yabo.
Okubalulekile! Lapho kuvela into ekhangayo, i-sickle shark ngeke ikhombise intshisekelo yayo esobala, kepha izoqala ukuzungeza imijikelezo yayo, ngezikhathi ezithile ijike ikhanda layo. Oshaka bakasilika nabo bayathanda ukugada eduze kwamaboy and sea izingodo.
Izazi ze-Ichthyologists ziqaphele ukungajwayelekile ngemuva koshaka (abangakakwazi ukuchaza) - ngezikhathi ezithile bashesha basuka ekujuleni baye phezulu, futhi lapho befinyelela enhlosweni yabo, bayaphenduka bagijimele kolunye uhlangothi. Oshaka bakasilika ngokuzithandela bahlala nenkampani yezando zethusi, bahlasela izikole zabo, futhi kwesinye isikhathi bahlelele izinhlanga ezincelisayo zasolwandle. Kuyaziwa, ngokwesibonelo, ukuthi kanye uma ushaka oyedwa ogqunywe ngomhlophe, oshaka abangu-25 nooshaka abampunga abamnyama abangama-25 balandela isikole esikhulu samahlengethwa asebhodleleni oLwandle Olubomvu.
Ubungako bukashaka kasilika namazinyo akhe abukhali (anamandla okuluma ama-Newtons angama-890) amele ingozi yangempela kubantu, futhi ukuhlaselwa kwabatshuzi kuqoshwe ngokusemthethweni. Kuyiqiniso, azikho eziningi kakhulu izimo ezinjalo, ezichazwa ukuvakashelwa okungajwayelekile koshaka ekujuleni okujulile. Ama-pilot fish nama-quarks ahlangana ngokuthula noshaka osilika. Owokuqala uthanda ukundiza phakathi kwamagagasi adalwe ushaka, kuyilapho owokugcina ethatha izinsalela zokudla kwakhe, abuye agcobe esikhunjeni sikashaka, asuse izimuncagazi.
Uhlala isikhathi esingakanani ushaka kasilika?
Izazi ze-Ichthyologists zithole ukuthi imijikelezo yokuphila koshaka bakasilika abahlala ezindaweni ezipholile nezishisayo ihlukile. Oshaka abahlala emanzini afudumele bakhula ngokushesha futhi bangena ebusheni. Yize kunjalo, ubude besikhathi sokuphila bezinhlobo (kungakhathalekile ukuthi imfuyo ikuphi) yiminyaka engama-22-23.
Indawo yokuhlala
Ushaka kasilika utholakala yonke indawo, lapho amanzi oLwandlekazi Lomhlaba afudunyezwa ngaphezu kuka-23 ° C. Ngokucabangela izici zomjikelezo wempilo, izichyyologists zihlukanisa abantu abahlukene aba-4 bakashaka besikela abahlala ezigodini eziningana zasolwandle, njenge:
- ingxenye esenyakatho-ntshonalanga yoLwandle i-Atlantic;
- empumalanga yePacific;
- I-Indian Ocean (kusuka eMozambique kuya eNtshonalanga Australia);
- imikhakha emaphakathi nasentshonalanga yoLwandlekazi iPacific.
Usilika ushaka uncamela ukuhlala olwandle oluvulekile, futhi ubonakala womabili eduze komhlaba nasezingxenyeni ezijulile kuze kufike ku-200-500 m (kwesinye isikhathi ngaphezulu). Ochwepheshe abaye babona oshaka enyakatho yeGulf of Mexico nasengxenyeni esempumalanga yePacific Ocean bathola ukuthi isabelo sengonyama sesikhathi (99%) sabadliwayo sasibhukuda ekujuleni kwamamitha angama-50.
Okubalulekile! Oshaka bokugula bavame ukuhlala eduze kwesheluvu lesiqhingi / izwekazi noma ngaphezulu kwamakhorali ajulile. Kwezinye izimo, oshaka baba sengcupheni yokungena emanzini asogwini, okujula kwawo okungenani kungu-18 m.
Oshaka besilika bayashesha futhi bayashesha: uma kunesidingo, babuthana emihlambini emikhulu (kufika kubantu abayinkulungwane) futhi bahamba ibanga elide (kufika ku-1,340 km). Ukufuduka koshaka besikela akukafundwa ngokwanele, kepha kuyaziwa, isibonelo, ukuthi abanye oshaka babhukuda cishe amakhilomitha angama-60 ngosuku.
Ukudla kukaSilika Shark
Ububanzi obukhulu bolwandle abugcwele izinhlanzi kangangoba ushaka kashaka uyithola ngaphandle komzamo obonakalayo.... Ijubane elihle (eliphindaphindwe ukukhuthazela), ukuzwa okubucayi nokuzwa okunephunga kuyamsiza ukuthi afune izikole zezinhlanzi eziminyene.
Ushaka uhlukanisa amasiginali aphansi emisindweni eminingi engaphansi kwamanzi, imvamisa ekhishwa izinyoni ezidla inyama noma amahlengethwa athole inyamazane. Umuzwa wokuhogela nawo udlala indima enkulu, ngaphandle kwalapho ushaka osilika ubungeke uqonde ebunzimeni bamanzi olwandle: umhlaseli uyakwazi ukuhogela inhlanzi ekumakhulu amamitha ukusuka kuyo.
Kuyathakazelisa! Ubumnandi obukhulu kakhulu bokudla okwenziwe ngoshaka kusuka ku-tuna. Ngaphezu kwalokho, etafuleni le-sickle shark kufinyelela etafuleni le-sickle shark. Ukwanelisa ngokushesha indlala yabo, oshaka baqhubela izinhlanzi ezikoleni ezimise okwibhola, zidlule kuzo zivule imilomo.
Ukudla kukashaka kasilika (ngaphandle kwe-tuna) kufaka:
- izinhlanzi zasolwandle namahhashi mackerel;
- i-mullet ne-mackerel;
- ama-snappers nama-bass olwandle;
- ama-anchovies akhanyayo nama-katrans;
- i-mackerel ne-eel;
- inhlanzi ye-hedgehog ne-triggerfish;
- ama-squid, izinkalankala nama-argonauts (octopus).
Oshaka abaningana badla endaweni eyodwa ngasikhathi sinye, kepha ngamunye wabo uyahlasela, angagxili ezihlotsheni. Ihlengethwa elinekhala lamabhodlela libhekwa njengelincintisana ngokudla kukashaka wesikela. Futhi, ochthyologists bathole ukuthi lolu hlobo lukashaka alunqikazi ukudla izidumbu zomkhomo.
Ukuzala nenzalo
Njengabo bonke abameleli bohlobo loshaka abampunga, i-sickle shark nayo ingeye-viviparous. Izazi ze-Ichthyologists zicabanga ukuthi izala unyaka wonke cishe yonke indawo, ngaphandle kweGulf of Mexico, lapho ukukhwelana / ukuzalwa kwenzeka ngasekupheleni kwentwasahlobo noma ehlobo (imvamisa ngoMeyi kuya ku-Agasti).
Abesifazane abathwala izingane izinyanga eziyi-12 babeletha njalo ngonyaka noma njalo ngonyaka. Abesifazane abavuthiwe ngokobulili bane-ovary eyodwa esebenzayo (kwesokudla) nesibeletho esisebenzayo esingu-2, bahlukaniswe ngobude baba ngamakamelo okuzimela embungu ngamunye.
Okubalulekile! I-placenta, lapho umbungu uthola ukudla okunomsoco, iyisikhwama se-yolk esingenalutho. Kuhlukile kuma-placenta abanye oshaka abathandekayo nezinye izilwane ezincelisayo ngoba izicubu zombungu nombele womama azithintani nhlobo.
Ngaphezu kwalokho, amangqamuzana egazi abomvu omama makhulu kakhulu kunalawo "wezingane". Ngokuzalwa, abesifazane bangena emaphethelweni emifula eshalofini lasezwenikazi, lapho bengekho oshaka abakhulu be-pelagic nokudla okuningi okufanelekile. Ushaka kasilika uletha oshaka abayi-1 kuye kwabayi-16 (kaningi - kusuka ku-6 kuye ku-12), ekhula ngo-0.25-0.30 m phakathi nonyaka wokuqala wokuphila kwakhe. Ezinyangeni ezimbalwa kamuva, izingane ziya ekujuleni kolwandle, kude nendawo lapho zizalelwa khona.
Amanani okukhula aphakeme kakhulu abonwa koshaka enyakatho yeGulf of Mexico, futhi aphansi kakhulu kubantu abalima amanzi ogwini olusenyakatho-mpumalanga yeTaiwan. Ichthyologists futhi ifakazisile ukuthi umjikelezo wempilo kashaka osilika awunqunywa kuphela indawo yokuhlala, kepha futhi nokwehluka kobulili: abesilisa bakhula ngokushesha okukhulu kunabesifazane. Abesilisa bayakwazi ukukhiqiza inzalo eminyakeni engaba ngu-6-10, kuyilapho abesifazane bengekho ngaphambi kweminyaka engu-7-12 ubudala.
Izitha zemvelo
Oshaka besilika ngezikhathi ezithile bashaya amazinyo oshaka abakhulu nemikhomo yokubulala... Njengoba kulindelwe lokhu kuguquka kwezinto, abamele abasha bezinhlobo bahlangana emaqenjini amaningi ukuze bazivikele esitheni esingaba khona.
Kuzothakazelisa futhi:
- Ingwe kashaka
- Ushaka ofanelekile
- Ushaka obuthuntu
- Whale shark
Uma ukushayisana kungenakugwenywa, ushaka ukhombisa ukulungela kwakhe ukulwa nokugoba iqolo, aphakamise ikhanda futhi ehlise amaphiko / umsila wepectoral. Khona-ke umhlaseli uqala ukunyakaza ngokungazelelwe emibuthanweni, engakhohlwa ukujika eceleni engozini engaba khona.
Inani labantu kanye nesimo sezinhlobo
Njengamanje, kunobufakazi obuningi bokuthi oshaka bakasilika olwandle baya ngokuncipha. Ukwehla kuchazwa yizinto ezimbili - isilinganiso somkhiqizo wentengiso kanye namandla amancane okuzala enhlobo, engenaso isikhathi sokubuyisa izinombolo zawo. Ngokuhambisana nalokhu, ingxenye enkulu yoshaka (njenge-by-catch) ifela kumanetha afakwa ku-tuna, okuyisibiliboco soshaka esiyintandokazi.
Oshaka bakasilika uqobo lwabo bazingelwa ikakhulukazi amaphiko abo, bebhekisa isikhumba, inyama, amanoni nemihlathi kashaka ngemikhiqizo. Emazweni amaningi, i-sickle shark ibhekwa njengento ebalulekile yokudoba ngenjongo yokuhweba nokuzilibazisa. Ngokwe-Food and Agriculture Organisation yeZizwe Ezihlangene, ngo-2000 ingqikithi yokukhiqizwa kukashaka kasilika kwaba ngamathani ayizinkulungwane eziyi-11.7, kwathi ngo-2004 - amathani ayizinkulungwane ezingama-4.36 kuphela. Lesi simo esingesihle singabonakala nasemibikweni yesifunda.
Kuyathakazelisa! Ngakho-ke, iziphathimandla zaseSri Lankan zamemezela ukuthi ngo-1994 ukubanjwa kukashaka kasilika kwakungamathani ayizinkulungwane ezingama-25,4, kwehle kwaba ngamathani ayizinkulungwane eziyi-1.96 ngo-2006 (okwaholela ekuweni kwemakethe yendawo).
Kuyiqiniso, akubona bonke ososayensi ababheka izindlela ezisetshenzisiwe zokuhlola isimo sabantu abahlala enyakatho-ntshonalanga ye-Atlantic naseGulf of Mexico njengezilungile.... Futhi izinkampani zokudoba zaseJapan ezisebenza olwandle iPacific / Indian Ocean azibonanga ukwehla komkhiqizo esikhaleni esivela eminyakeni yama-70s kuye kuma-90s wekhulu elidlule.
Kodwa-ke, ngo-2007 (ngenxa yemizamo ye-International Union for Conservation of Nature), ushaka wanikezwa isikhundla esisha esisebenza kuyo yonke iplanethi - "eduze nendawo esengozini." Ezingeni lesifunda, ngokunembile, empumalanga / eningizimu-mpumalanga ye-Pacific Ocean nasentshonalanga / enyakatho-ntshonalanga yengxenye ye-Central Atlantic, lolu hlobo lunesimo "esisengozini".
Abalondolozi bemvelo bathemba ukuthi ukuvinjelwa kokuqeda imali e-Australia, e-United States nase-European Union kuzosiza ekulondolozeni inani loshaka besikela. Izinhlangano ezimbili ezibucayi zenze izindlela zazo zokwenza ngcono ukuqapha ukudotshwa ukuze kuncishiswe ukudotshwa koshaka besilika:
- IKhomishini ye-Inter-American for the Conservation of Tropical Tuna;
- IKhomishini Yomhlaba Wonke Yokongiwa Kwe-Atlantic Tuna.
Kodwa-ke, ochwepheshe bayavuma ukuthi ayikho indlela elula yokwehlisa ukubamba okungadluli okwamanje. Lokhu kungenxa yokufuduka okuvamile kwezinhlobo ezihambisana nokunyakaza kwe-tuna.
