Morfološka i genetička raznovrsnost vrsta Carassius auratus sa teritorije Vojvodine i peripanonske oblasti

Abstract

Prema novijim istraživanjima, kompleks Carassius auratusčini najmanje pet vrsta roda Carassius: Carassius carassius, Carassius auratus, Carassius langsdorfii, Carassius cuvieri i Carassius gibelio. Vrste ovog roda su morfološki veoma slične i nemoguće ih je razlikovati na osnovu uobičajenih morfoloških karaktera, te su ranije sve determinisane kao Carassius auratus gibelio ili Carassius gibelio. Jedina vrsta koja se značajnije razlikuje je Carassius carassius. Smara se da su vrste ovog kompleksa unesene u Evropu iz Azije u 17. veku. Najveći broj predstavnika kompleksa C. auratus je na teritoriji Evrope proteklih pedesetak godina determinisan je kao vrsta Carassius gibelio(C. auratus gibelio) (Bloch, 1783) (srebrni karaš ili babuška). S obzirom da su pripadnici ovog kompleksa registrovani u većini vodotokova Evrope, smatraju se najuspešnijom invazivnom grupom slatkovodnih riba. Zbog svojih bioloških odlika (brz rast, različiti vidovi razmnožavanja, izuzetna otpornost na nepovoljne uslove) ove vrste veoma brzo postaju kompetitivne autohtonoj ihtiofauni za hranu i stanište i neretko imaju izuzetno negativan uticaj na celokupan ekosistem koji nasele. U ovoj disertaciji prvi put je izvršena identifikacija vrsta kompleksa Carassius auratus na teritoriji Vojvodine i peripanonske oblasti primenom specifičnih genetičkih markera (dela sekvence cytb gena). Primenom linearne i geometrijske morfometrije ispitivana je morfološka varijabilnost različitih morfoloških celina (celo telo, kosti glavenog skeleta, cleithrum-a i krljušti) jedinki unutar kompleksa Carassius auratusizmeđu različitih lokaliteta sa različitim ekološkim uslovima (prisustvo predatora i protok), dok je primenom savremenih statističkih i matematičkih metoda (multi-modelne analize) analizirana dinamika rasta recentnih, kao i ranoinvazivnih populacija. Metaanalizom dostupnih podataka utvrđena je veoma široka zastupljenost populacija vrsta kompleksa C. auratus na teritoriji Srbije. Beležene populacije su uglavnom pokazivale srednju do visoku zastupljenost (20-40%) u ukupnoj ihtiofauni uz uočljivo povećanje brojnosti u funkciji vremena. Na nekim lokalitetima se u nekoliko uzastopnih studija registruju veoma brojne popu-lacije vrsta ovog kompleksa (40-100% u ukupnom ulovu). Za potrebe molekularno- taksonomskih analiza i analiza morfološke varijabilnosti recentnih populacija uzorkovano je 280 jedinki u periodu 2012 – 2014.godine sa 14 različitih lokaliteta u Vojvodini i peripanonskoj oblasti. Sve jedinke u uzorku su prvo fotografisane za potrebe analiza linearne i geometrijske morfometrije, uzet je uzorak repnog peraja za dalje genetičke analize, a nakon toga su izvršena sva neophodna merenja morfometrijskih i merističkih karaktera radi ana-lize varijabilnosti među populacijama. Populaciono-genetičkim analizama sekvenci dela cytb gena utvrđeno je da su sve ispitivane jedinke pripadale vrsti Carassius gibelio I. Zbog biološkog stanja uzoraka, determinacija je bila moguća za samo 52 jedinki sa 11 lokaliteta te se ne bi smela isključiti mogućnost postojanja još nekih vrsta kompleksa C. auratus, kao što su C. auratus i C. langsdorfi koje su prema navodima drugih autora beležene na teritorijama susednih zemalja. Primenom linearne i geometrijske morfometrijske analize ustanovljena je izražena fenoti-pska varijabilnost u obliku tela i odabranih elemenata skeletnog sistema između riba sa različitih lokaliteta. Utvrđeno je odsustvo polnog dimorfizma. Najveću varijabilnost od svih morfoloških parametara pokazala je vrednost za visinu tela, i veličinu glave, dok su kod kostiju najviše varirale vrednosti za os pharyngii na kojoj su ždrelni zubi - dentes pharyngii. Prisustvo predatora i protok vode na ispitivanim lokalitetima su ispoljili uticaj na morfološku varijabilnost riba. Prisustvo predatora je uslovilo pojavu karakterističnog fenotipa riba sa visokim telom koje omogućava lakše izbegavanje predatora. Za analizu mofološke varijabilnosti ranih invazivnih populacija vrsta kompleksa C. auratus korišćeni su podaci za 524 jedinke (prilikom izlova determinisane kao C. auratus gibelio) sa tri lokaliteta u Vojvodini iz perioda 1983 – 1985. godine. Lokaliteti su izabrani prema različitom načinu invazije vrsta kompleksa C. auratus. Analizama linearne morfometije i modela rasta ut-vrđeno je da su se lokaliteti na kojima su bile zastupljene namerne antropogene introdukcije nepoznatog porekla odlikovali mnogo većom morfološkom varijabilnošću od lokaliteta u koje su jedinke dospele prirodnim putevima invazije izvećih vodotokova. Analizama životne istorije i dinamike rasta na 395 jedinki vrsta kompleksa C. auratus (pri-likom uzorkovanja determinisanih kao C. gibelio) kao invazivne grupe riba i 429 jedinki bodorke kao predstavnika autohtone ihtiofaune u periodu između 1991. i 1999. godine na akumulacijama Međuvršje i Gruža utvrđene su razlike između različitih tipova staništa. Nezavisno od vrste, utvrđeno je da jedinke koje žive u sporim i plitkim staništima su krupnije i dostižu veće asimptotske dužine od individua koje nastanjuju brže i uže vodotokove. Ovaj rad je među prvim koji primenjuje multi-modelnu analizu u modelovanju rasta slat-kovodnih riba. Rezultati su pokazali da se ova metoda može implementirati i na invazivne vrste riba kako bi se bolje procenio njihov uticaj na autohtonu faunu i eventualno razvile uspešnije strategije upravljanja i kontrole njihovih populacija.

According to recent researches, Carassius auratus complex includes at least five Carassius species: Carassius carassius, Carassius auratus, Carassius langsdorfii, Carassius cuvieri and Carassius gibelio. These species are morphologically very similar and it is impossible to differentiate them on the basis of common morphological characters, so they all used to be classified as Carassius auratus gibelio or Carassius gibelio. The only species that is significantly different is Carassius carassius. It is believed that the species of this complex were brought to Europe from Asia in the 17th century. Over the last fifty years most of the members of C. auratus complex in Europe were classified as Carassius gibelio (C. auratus gibelio) (Bloch, 1783) (Silver carp or Gibel carp). Since the members of this complex have been registered in most European watercourses, they are considered to be the most successful invasive group of freshwater fish. Thanks to their biological characteristics (fast growth, different types of reproduction, remarkable resistance to unfavourable conditions) these species quickly become competitive to indigenous ichthyofauna in respect of food and habitat and they often have very negative impact on the entire ecosystem they inhabit. This dissertation identifies the species that belong to the Carassius auratus complex in /Vojvodina and peri-Pannonian region using specific genetic markers (ctyb gene sequence). Using linear and geometric morphometrics, we examined morphological variability of different morphological parts (whole body, skull bones, cleithrum and scales) of the members of Carassius auratus complex, in different localities with different ecological conditions (presence of predators and water flow). Modern statistics and mathematical methods (multi-model analysis) were used in the analysis of growth dynamics of both recent and early invasive populations. Meta-analyses of the available data have shown that there is a wide population of C. auratuscomplex species in Serbia. The examined populations showed medium to high occurrence (20- 40%) in the entire ichthyofauna, with evident growth over time. A few consecutive studies have registered very large populations of the species of this complex in several localities (40-100% of total catch). For the purpose of molecular-taxonomic analyses and the analysis of morphological variability of recent populations, we used a sample of 280 units taken in 14 different localities in Vojvodina and peri-Pannonian region in the period from 2012 to 2014. All the units in the sample were first photographed for the purpose of linear and geometric morphometrics, samples of tail fins were taken for further genetic analysis, and then all the necessary evaluations of morphometric and meristic characters were made, as well as the analysis of variability among populations. Population genetic analysis with the application of a genetic marker (cytb gene) has shownthat all the examined units belong to Carassius gibelio species. Due to the biological state of the samples, the determination was possible for only 52 units from 11 localities, so it not impossible that some other species of C. auratus complex such as C. auratus and C. langsdorficould also be found in this region as they have been registered on the territories of the neighbouring countries, as reported by some authors. Linear and geometric morphometric analysis has shown significant phenotype variability in body shape and selected elements of the skeletal system. It has also proved the absence of sexual dimorphism and showed that locality had a major impact on the variability. The largest variability was recorded in terms of body height and head size, while the most variable values with the bones were those referring to os pharyngii with pharyngeal teeth. Morphological variability of fish also depended on the presence of predators and the water flow in the examined localities. The presence of predators causes a characteristic phenotype of fish with tall body which enables them to avoid predators more easily. In the analysis of morphological variability of early invasive populations of the species of C. auratus complex we used data for 524 units (classified as C. auratusgibelio during the catch) from three localities in Vojvodina in the period from 1983 to 1985. The localities were chosen according to different ways of invasion of the species of C. auratus complex. Linear morphometrics and growth model analyses have shown that the localities with deliberate anthropogenic introduction of unknown origin were characterized with greater variability than the localities populated by natural invasion from larger watercourses. The analyses of life history and growth dynamics in 395 members of the species of C. auratuscomplex (classified as C. gibelio during the sampling) as an invasive group of fish, and 429 units of the roach as the representative of the indigenous ichthyofauna in the artificial lakes of Međuvršje and Gruža in the period from 1991 to 1999, have established differences among different types of habitats. Regardless of species, the fish that live in slow and shallow habitats are larger and they reach greater asymptotic length than those living in faster and narrower watercourses. This study is among the first ones to apply multi-model analyses in modeling freshwater fish growth. The results have shown that this method can be implemented in studying invasive fish species in order to make a better estimation of their influence on indigenous fauna and possibly develop more successful strategies of managing and controlling their populations.