Marijan Govedič (Avtor), Franc Janžekovič (Avtor), Ivan Kos (Avtor)

Povzetek

Avtorji so z analizo izbljuvkov ugotavljali prehrano kormoranov Phalacrocorax carbo, ki so se prehranjevali na območju reke Save od Ljubljane do Zagorja v zimi 1998/99. Izbljuvke so pobirali na prenočišču pri Hotiču. Izmed 473 izbljuvkov so bili v 69,8 % ostanki rib. V izbljuvkih so bile tudi gliste Nematoda in trakulje Cestoda ter ostanki mladoletnic Trichoptera, polžev Gastropoda in ene žabe Rana sp. V izbljuvku so bili ostanki 1 do 69 rib (Mediana 2, Povprečje 3,9). V 41,8 % izbljuvkov je bila samo ena riba, v 93,6 % izbljuvkov pa do 10 rib. Našli so ostanke 1288 osebkov rib. 1279 osebkom so določili dolžino in maso. Skupaj so tehtali 57 kg. Določili so 12 vrst rib. V izbljuvkih so našli ostanke lipana Thymallus thymallus, postrvi Salmo trutta, klena Leuciscus cephalus, podusti Chondrostoma nasus, platnice Rutilus pigus virgo, rdečeoke Rutilus rutilus, navadne mrene Barbus barbus, ploščiča Abramis brama, zelenike Alburnus alburnus, ščuke Esox lucius, navadnega ostriža Perca fluviatilis in navadnega okuna Gymnocephalus cernuus. V prehrani so prevladovali krapovci Cyprinidae (85,8 % po številu in 90,5 % po masi). Lipan in postrv sta sestavljala 6,5 % po številu in 3,6 % po masi ter ščuka in navadni ostriži 7,3 % po številu in 3,6 % po masi. Znotraj krapovcev sta bila najpogostejša klen (16,4 % po številu in 38,6 % po masi) in podust (3,9 % po številu in 16,5 % po masi). Delež nedoločenih krapovcev je bil 57,1 % po številu in 28,5 % po masi. Dolžina rib je bila od 23 do 345 mm. Najpogostejši velikostni razred, ki so ga plenili kormorani, je bil 70-170 mm (50 % po številu, 19 % po masi), vendar smo zaključili, da so veliki osebki (>170 mm) sestavljali najpomebnejši delež (25,0 % po številu, 80,1 % po masi) v prehrani kormoranov. Število osebkov krapovcev, ostrižev in salmonidov med meseci je bilo statistično značilno različno, število osebkov posameznih vrst določenih krapovcev pa ne. Zaključili smo, da so razlike odvisne predvsem od naključja, na katero vrsto rib so kormorani naleteli. Klen in podust, ki se združujeta v večje jate, sta na območju za kormorana najverjetneje najbolj odkrivni vrsti.

Ključne besede

ptice;kormorani;ribojede ptice;Phalacrocorax carbo;prehrana;zimska prehrana;analize;Slovenija;Sava;ne zaključna dela;

Podatki

Jezik: Slovenski jezik
Leto izida:
Tipologija: 1.01 - Izvirni znanstveni članek
Organizacija: UM PEF - Pedagoška fakulteta
Založnik: Društvo za opazovanje in proučevanje ptic Slovenije
UDK: 598.8(497.4)
COBISS: 12042504 Povezava se bo odprla v novem oknu
ISSN: 0351-2851
Matična publikacija: Acrocephalus
Št. ogledov: 1415
Št. prenosov: 48
Ocena: 0 (0 glasov)
Metapodatki: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Ostali podatki

Sekundarni jezik: Angleški jezik
Sekundarni naslov: ǂThe ǂdiet of great cormorants Phalacrocorax carbo on the Sava river between Ljubljana and Zagorje (Slovenia)
Sekundarni povzetek: Diet of Great Cormorants Phalacrocorax carbo occurring on the Sava river between Ljubljana and Zagorje was studied in the winter 1998/99 by means of regurgitated pellets, collected at the Cormorants' night roost at Hotič. Among 473 collected pellets, 69.8 % contained remains of fish. The pellets also contained worms Nematoda and tapeworms Cestoda, remains of caddis flies trichoptera, snails Gastropoda and a frog Rana sp. In separate pellets, remains of 1 to 69 fish (median 2, average 3.9) were found: in 41.8 % pellets remains of 1 fish, in 93.6 % remains of up to 10 fish. Altogether, remains of 1,288 fish were found. Length and weight were determined for 1,279 of them. Total weight of these fish was estimated at 57 kg. The diet consisted of 12 fish species (trout Salmo trutta, grayling Thymallus thymallus, chub Leuciscuscephalus, nase Chrondrostoma nasus, danube roach Rutilus pigus virgo,roach Rutilus rutilus, barbel Barbus barbus, bream Abramis brama, bleak Alburnus alburnus, pike Esox lucius, perch Perca fluviatilis and ruffe Gymnocephalus cernuus). The diet was dominated by Cyprinidae (85.8 % by number, 90.5 % by biomass). Gravling and trout were represented with 6.5 % by number and 3.6 % by mass and pike, perch and ruffe in 7.3 % by number and 3.6 % by mass. Inside Cyprinidae chub with 16.4 % by number and 38.6 by biomass and nase with 3.9 % by number and 16.5 % by biomass were most frequent. The proportion of undetermined Cyprinidae was 57.1 % by number and 28.5 % by mass. Prey size ranged from 23 to 345 mm. Most frequent length class was 70-170 mm (50 % by number and 19 % by mass), but large individuals (170 mm) were most important (25.0 % by number and 80.1 % by mass) in the diet of Great Cormorants. The numbers of specimens of Cyprinidae, Percidae and Salmonidae between months were significant, while the numbers of specimens of determined Cyprinids were not. We concluded that the differences in the investigated area depended more on random detection of fish. Chub and nase arespecies with shoaling habits, and were assumed that they were easier detectable by Great Cormorants than the non-shoaling species.
Sekundarne ključne besede: birds;great cormorant;Phalacrocorax carbo;piscivorous birds;food;winter diet;analises;Slovenia;Kormorani;Živalska prehrana (fiziologija);Slovenija;
URN: URN:NBN:SI
Vrsta dela (COBISS): Znanstveno delo
Strani: str. 5-20
Letnik: ǂLetn. ǂ23
Zvezek: ǂšt. ǂ110/111
Čas izdaje: 2002
ID: 1747292