High levels of organochlorines may affect hatching sex ratio and hatchling body mass in arctic glaucous gulls

• Published in: Functional ecology Vol. 25; no. 1; pp. 289 - 296
• Main Authors: Erikstad, Kjell Einar, Moum, Truls, Bustnes, Jan O., Reiertsen, Tone K.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2011; Blackwell Publishing; Wiley-Blackwell; Wiley Subscription Services, Inc
• Subjects: Animal and plant ecology; Animal growth and development; Animal, plant and microbial ecology; Autoecology; Aves; Biological and medical sciences; Body condition; Chicks; Ecology; Eggs; endocrine disruption; Female animals; Females; Food chains; Fundamental and applied biological sciences. Psychology; General aspects; glaucous gull; Hatching; hatchling body mass; Human ecology; Larus hyperboreus; Male animals; Marine; organochlorines; Sea birds; Sex ratio; Sexes; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Arctic Region; PNE, Norway, Svalbard, Spitsbergen; PNE, Barents Sea, Bear Island; Norway; PN, Arctic; Sex ratio; organochlorines; Vertebrata; Hatching; Organochlorine compounds; hatchling body mass; Body weight; Endocrine disruptor; Aves; glaucous gull; endocrine disruption
• ISSN: 0269-8463; 1365-2435
• DOI: 10.1111/j.1365-2435.2010.01771.x

1. Long range transportation via ocean currents and air of various organochlorines (OCs) has resulted in their intrusion in the high Arctic marine food web. At the Spitsbergen archipelago, including Bear Island (Norway), bioaccumulation in top predators like glaucous gulls (Larus hyperboreus) is high, severely affecting their breeding performance and survival. 2. In the present study, we examined the sex ratio of glaucous gull offspring at hatching in relation to the OC blood levels of female parents. Glaucous gulls have male-biased size dimorphism and females under stress with high levels of OCs are expected to skew the sex ratio towards the less costly female offspring. 3. Our data strongly suggest that among females with low levels of OCs, mothers in good body condition had a hatching sex ratio skewed towards males while those in poor body condition had a skew towards female offspring. However, contrary to expectations, females with high levels of OCs had a strong skew in sex ratio toward male offspring and this was most apparent among females in poor body condition. 4. Hatching body masses of male chicks (controlled for egg size) were negatively related to OC blood level of female parents. There was no such relationship for female offspring. 5. We discuss the skew in hatching sex ratio experienced by OC contaminated glaucous gulls in light of three hypotheses. One is that OC pollutants may mimic hormones and influence the sex determining processes suggested to be under control of steroids. Another is that female transfer of OCs to eggs may increase female embryo mortality. A third hypothesis is that elevated levels of OCs could trigger increased parental investment (terminal investment) which may represent an abortive strategy for OC contaminated gulls, further aggravating the negative impact of OCs on gull population parameters.