Can Thermoclines Be a Cue to Prey Distribution for Marine Top Predators? A Case Study with Little Penguins
نویسندگان
چکیده
The use of top predators as bio-platforms is a modern approach to understanding how physical changes in the environment may influence their foraging success. This study examined if the presence of thermoclines could be a reliable signal of resource availability for a marine top predator, the little penguin (Eudyptula minor). We studied weekly foraging activity of 43 breeding individual penguins equipped with accelerometers. These loggers also recorded water temperature, which we used to detect changes in thermal characteristics of their foraging zone over 5 weeks during the penguin's guard phase. Data showed the thermocline was detected in the first 3 weeks of the study, which coincided with higher foraging efficiency. When a thermocline was not detected in the last two weeks, foraging efficiency decreased as well. We suggest that thermoclines can represent temporary markers of enhanced food availability for this top-predator to which they must optimally adjust their breeding cycle.
منابع مشابه
Differences in Diving Behaviour Optimality May Cause Differences in Reproductive Success in Chinstrap Penguins: A Cases Study
Bio-logging is a useful technique for obtaining information on foraging behaviour, physiology, and environmental conditions from animals in marine ecosystems. By integrating this information, researchers can investigate the ecology of general prey-predator system in terms of their optimal behaviour with the help of theoretical models. In the present study, I analyse the diving behaviour of two ...
متن کاملSearching for the True Diet of Marine Predators: Incorporating Bayesian Priors into Stable Isotope Mixing Models
Reconstructing the diet of top marine predators is of great significance in several key areas of applied ecology, requiring accurate estimation of their true diet. However, from conventional stomach content analysis to recent stable isotope and DNA analyses, no one method is bias or error free. Here, we evaluated the accuracy of recent methods to estimate the actual proportion of a controlled d...
متن کاملBenefits of Group Foraging Depend on Prey Type in a Small Marine Predator, the Little Penguin
Group foraging provides predators with advantages in over-powering prey larger than themselves or in aggregating small prey for efficient exploitation. For group-living predatory species, cooperative hunting strategies provide inclusive fitness benefits. However, for colonial-breeding predators, the benefit pay-offs of group foraging are less clear due to the potential for intra-specific compet...
متن کاملEcological nichemodeling of sympatric krill predators aroundMarguerite Bay, Western Antarctic Peninsula
Adélie penguins (Pygoscelis adeliae), carabeater seals (Lobodon carcinophagus), humpback (Megaptera novaeangliae), and minke whales (Balaenoptera bonaernsis) are found in the waters surrounding the Western Antarctic Peninsula. Each species relies primarily on Antarctic krill (Euphausia superba) and has physiological constraints and foraging behaviors that dictate their ecological niches. Unders...
متن کاملStraight Line Foraging in Yellow-Eyed Penguins: New Insights into Cascading Fisheries Effects and Orientation Capabilities of Marine Predators
Free-ranging marine predators rarely search for prey along straight lines because dynamic ocean processes usually require complex search strategies. If linear movement patterns occur they are usually associated with travelling events or migratory behaviour. However, recent fine scale tracking of flying seabirds has revealed straight-line movements while birds followed fishing vessels. Unlike fl...
متن کامل