ESTIMATING DIET COMPOSITION OF THE AUSTRALIAN SEA-LION (NEOPHOCA-CINEREA) FROM SCAT ANALYSIS - AN UNRELIABLE TECHNIQUE

被引:83
作者
GALES, NJ [1 ]
CHEAL, AJ [1 ]
机构
[1] ATLANTIS MARINE PK,TWO ROCKS,WA 6037,AUSTRALIA
关键词
D O I
10.1071/WR9920447
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
Knowledge of the diet of the Australian sea-lion (Neophoca cinerea) has been restricted to anecdotal, qualitative accounts. In this study, we tested the validity of using identifiable prey remains in scats to quantify the diet of N. cinerea by analysis of scats from free-ranging sea-lions and feeding trials on captive sea-lions. Identifiable remains in the scats of free-ranging animals occurred infrequently: otoliths (n = 8) were present in only 9% of scats, cephalopod beaks (n = 23) in only 24% and lobster (Panulirus cygnus) remains in 7%. These limited data, combined with analysis of contents of five stomachs, indicated that N. cinerea has a broad diet and feeds on some benthic species. Feeding trials on two captive sea-lions demonstrated that scats were not representative of the diet. Fewer than 2% of ingested otoliths (by number) were recovered in scats. Otoliths less than 5 mm long were absent from scats; recovery of larger otoliths increased with their size. Defaecated otoliths were eroded by at least 28% (by length) during digestion. Transit of cephalopod mouth parts in two captive animals was variable (98% and 9% recovery), with only beaks of small cephalopods passing through the pyloric canal. The complete digestion of otoliths in transit through the gut tract and the variable recovery of cephalopod beaks indicated that scats cannot be used even for a qualitative description of the diet of N. cinerea.
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页码:447 / 456
页数:10
相关论文
共 26 条
[1]  
ANDERSON SS, 1974, J ZOOL, V174, P429, DOI 10.1111/j.1469-7998.1974.tb03170.x
[2]  
Bigg M.A., 1985, P284
[3]   A REVIEW OF ECOLOGICAL APPLICATIONS OF IMMUNOLOGICAL TECHNIQUES FOR DIET ANALYSIS [J].
CALVER, MC .
AUSTRALIAN JOURNAL OF ECOLOGY, 1984, 9 (01) :19-25
[4]  
CLARKE MR, 1982, BR ANTARCT SURV B, V57, P33
[5]  
CLARKE MR, 1962, B BRIT MUS NAT HIST, V8, P433
[6]   LIMITATIONS OF USING OTOLITHS RECOVERED IN SCATS TO ESTIMATE PREY CONSUMPTION IN SEALS [J].
DASILVA, J ;
NEILSON, JD .
CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES, 1985, 42 (08) :1439-1446
[7]   ESTIMATING DIET COMPOSITION FROM SCAT ANALYSIS IN OTARIID SEALS (OTARIIDAE) - IS IT RELIABLE [J].
DELLINGER, T ;
TRILLMICH, F .
CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE, 1988, 66 (08) :1865-1870
[8]  
FROST KJ, 1981, FISH B-NOAA, V79, P187
[9]  
GALES NJ, 1988, AUST WILDLIFE RES, V15, P423
[10]   THE DIET OF ANTARCTIC FUR SEALS ARCTOCEPHALUS-GAZELLA (PETERS) DURING THE BREEDING-SEASON AT HEARD ISLAND [J].
GREEN, K ;
BURTON, HR ;
WILLIAMS, R .
ANTARCTIC SCIENCE, 1989, 1 (04) :317-324