Dynamic enforcement of bycatch via reproductive value can increase theoretical efficiency

• Published in: Marine Policy
• Main Authors: Shaffer, Scott, Blévin, Pierre, Barbraud, Christophe, Chastel, Olivier, Weimerskirch, Henri, Michael, Pamela, Wilcox, Chris, Delord, Karine, Sumner, Michael
• Other Authors: San Jose State University San Jose (SJSU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDV]Life Sciences [q-bio]; Dumont d’Urville; Nivea; Antarc*; Antarctica; Cape Petrels; Daption capense; Snow Petrel; Snow Petrels
• Online Access: https://hal.archives-ouvertes.fr/hal-03376166; https://doi.org/10.1016/j.marpol.2021.104684

International audience Abstract Background The internal environment of eggs in most birds is regulated by transferring heat energy through contact incubation, maintaining nest microclimate, and frequent egg turning by the incubating parent on its nest. However, we lack information about egg attendance patterns in birds that breed in polar environments where variations in life history are expected to influence incubation behavior. Moreover, crevice/burrow nesting petrels in high-latitude regions are known for periodically leaving their egg unattended (hereafter ‘egg neglect’), but there is little reporting on the internal condition of unattended eggs. At Dumont d’Urville Station, Antarctica, we studied the incubation behavior of 24 snow ( Pagodroma nivea ) and 15 Cape ( Daption capense ) petrel pairs using egg loggers that recorded egg turning rates, orientation changes, and temperatures at 1 Hz for durations of 3–6 days. Results Egg turning frequency (1.31 ± 0.33 vs. 1.38 ± 0.39 turns h −1 ), angle change per turn (43.1 ± 43.2 vs. 48.6 ± 43.7° turn −1 ), and egg temperature (34.1 ± 2.3 vs. 34.1 ± 2.0 °C) were nearly identical for snow and Cape petrels, respectively. However, egg neglect was only observed in snow petrel nests (based on egg temperature changes) where loggers recorded mean durations of 1.34 ± 1.15 days (maximum duration of 3.63 days). During periods of neglect, eggs cooled to 5.5 ± 1.8 °C over an average of 91 min, but were rewarmed by parents in only 76 min at a rate of 0.33 °C min −1 . Conclusions Egg temperatures of both species during regular incubation were within 1–2 °C of other high-latitude petrel species, but neglected snow petrel eggs remained several degrees above freezing, which was likely attributed to crevice nesting where neglected eggs are buffered by environmental conditions. Using egg rewarming rates, thermal capacity of eggs, and published metabolic rates, we estimate egg rewarming costs in snow petrels to be 1.5 to 1.9 × BMR. Excluding egg neglect periods, turning rates for ...