Changes in Foraging Range of Audouin's Gulls Larus audouinii in Relation to a Trawler Moratorium in the Western Mediterranean

1996 ◽  
Vol 19 (1) ◽  
pp. 128 ◽  
Author(s):  
Jose Manuel Arcos ◽  
Daniel Oro
Keyword(s):  
Western Mediterranean ◽  
Foraging Range ◽  
Larus Audouinii

Offspring sex ratios in subcolonies of Audouin's gull, Larus audouinii, with differential breeding performance

2003 ◽  
Vol 81 (5) ◽  
pp. 905-910 ◽  
Author(s):  
Meritxell Genovart ◽  
Lluís Jover ◽  
Xavier Ruiz ◽  
Daniel Oro
Keyword(s):  
Breeding Success ◽  
Sex Ratios ◽  
Western Mediterranean ◽  
Foraging Efficiency ◽  
Molecular Sexing ◽  
Mendelian Segregation ◽  
Breeding Parameters ◽  
Western Mediterranean Sea ◽  
Offspring Sex ◽  
Larus Audouinii

At the Ebro River delta colony in the western Mediterranean Sea, Audouin's gull, Larus audouinii, breeds in discrete aggregations called subcolonies, which showed strong differences in breeding parameters such as egg volume or breeding success. Egg parameters (such as size of both eggs and clutches) are strongly influenced by food availability. As all subcolonies are in the same area, differences in egg parameters might reflect different individuals' foraging efficiency. We measured mean clutch volumes in different subcolonies and chose those subcolonies that showed the greatest differences in this measure, which should indicate differences in parental body condition. Between these subcolonies we would expect, in turn, differences in offspring sex ratios. We took blood samples at hatching and fledging from chicks at these subcolonies and compared offspring sex ratios by means of molecular sexing. The proportions of young breeders differed between these subcolonies, and the subcolony with the greater proportion of young breeders produced smaller eggs and had lower breeding success. However, we did not detect any bias in progeny sex ratio, which probably indicates that if parental condition is not extremely reduced, selective pressures are insufficient to overcome the constraints imposed by Mendelian segregation of chromosomes.

scholarly journals Persistent Pollutants in Audouin's Gull (Larus audouinii) in the Western Mediterranean: A Case-study with Wide Implications?

1979 ◽  
Vol 6 (2) ◽  
pp. 139-142 ◽  
Author(s):  
M. F. I. J. Bijleveld ◽  
P. Goeldlin ◽  
J. Mayol
Keyword(s):  
Reproductive Success ◽  
Western Mediterranean ◽  
Organochlorine Compounds ◽  
Chemical Analyses ◽  
Persistent Pollutants ◽  
Larus Audouinii

The possibility of persistent pollutants playing an adverse role in the reproductive success of Audouin's Gull in the western Mediterranean was examined through chemical analyses of 7 eggs of this species that did not hatch. Residues of organochlorine compounds and mercury were found.The conclusion has been reached that a further increase of present levels of DDE may well lead to a decline of the reproductive success of the species in the western Mediterranean, especially in the northern part. These observations, although limited, could have implications for further species as is already indicated by other work cited.

Pollutant lad sources and deposition in the Western Mediterranean

2003 ◽  
Vol 107 ◽  
pp. 875-878 ◽  
Author(s):  
J. Miralles ◽  
O. Radakovitch ◽  
A. Véron ◽  
J. K. Cochran ◽  
P. Masqué ◽  
...  
Keyword(s):  
Western Mediterranean
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