Importance of the Japanese anchovy (Engraulis japonicus) to breeding rhinoceros auklets, (Cerorhinca monocerata) on Teuri Island, Sea of Japan

Citation
A. Takahashi et al., Importance of the Japanese anchovy (Engraulis japonicus) to breeding rhinoceros auklets, (Cerorhinca monocerata) on Teuri Island, Sea of Japan, MARINE BIOL, 139(2), 2001, pp. 361-371
Citations number
52
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Aquatic Sciences
Journal title
MARINE BIOLOGY
ISSN journal
0025-3162 → ACNP
Volume
139
Issue
2
Year of publication
2001
Pages
361 - 371
Database
ISI
SICI code
0025-3162(200108)139:2<361:IOTJA(>2.0.ZU;2-J
Abstract
Temporal variation in the diet and chick growth of rhinoceros auklets (Cero rhinca monocerata), on Teuri Island., Sea of Japan, was studied to understa nd how local marine environmental changes affect the reproduction of this p iscivorous seabird. The food delivered by parents to chicks was sampled eve ry 1-2 weeks from late May to July, 1994-1998. Overall, the diet of nestlin g rhinoceros auklets consisted of (by mass) 61 % Japanese anchovy (Engrauli s japonicus), 18% Japanese sand lance (Ammodytes personatus), 18% Japan Sea greenling (Pleurogrammus azonus), 2% other fish and 1% squid. Among years, the contribution of anchovy ranged from 16% to 93%. Once anchovy occurred in the diet, it dominated (80% on average) thereafter. Accordingly, when an chovy appeared in the diet early in the chick-rearing season (1994, 1998), the contribution of anchovy overall was large. The first appearance of anch ovy in the diet of auklets late in the summer of 1997 was possibly related to negatively anomalous sea-surface temperature. Food loads composed of anc hovy (34.0 g) were heavier than those of sand lance (22.5 g) and greenling (28.5 g). I The energy density of anchovies also was higher: 6.3 kJ g(-1) w et mass compared to 0+ greenling (4.78 kJ g(-1)) and 0+ sand lance (3.78 kJ g(-1)). Thus, a high proportion of anchovy in the diet resulted in high fo od load mass, high daily growth rates of chicks and high fledging success. This study highlighted the importance of the time of arrival of migratory h igh-lipid prey, which is influenced by local oceanographic conditions, to t he reproductive performance of a piscivorous seabird.