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Determining the form of key predator-prey relationships is critical for understanding marine ecosystem dynamics. Using a comprehensive global database, we quantified the effect of fluctuations in food abundance on seabird breeding success. We identified a threshold in prey (fish and rill, termed \"forage fish\") abundance below which seabirds experience consistently reduced and more variable productivity. This response was common to all seven ecosystems and 14 bird species examined within the Atlantic, Pacific, and Southern Oceans. The threshold approximated one-third of the maximum prey biomass observed in long-term studies. This provides an indicator of the minimal forage fish biomass needed to sustain seabird productivity over the long term.

The life histories of organisms can show pronounced variation in the way that the costs of reproduction are financed. To facilitate discussions of this variation, two terms are increasing in use: “capital breeding” describes the situation in which reproduction is financed using stored capital; “income breeding” refers to the use of concurrent intake to pay for a reproductive attempt. We consider the value of the capital and income typology with reference to three functions that it might serve: description, explanation, and prediction. We find that interpretations of the terms have diversified and lack rigidity, leading to subjectivity in their definition. We recognize that time frames of interest will vary among taxa, but we urge consistency of use within those taxa. We also urge consistency in the use of a single metric designed to measure the reliance of an organism on capital. The concepts of capital and income breeding have served well as proximate explanations for behavioral or physiological diversity, but efforts to explain their adaptive value have been disproportionately focused on individual taxa. Mapping cause to effect is difficult in ecology. Nevertheless, further analyses, based on consistently applied measures of reliance on stored capital, may reveal which of the putative ecological, morphological, and physiological drivers have the most consistent and widespread effects. The capital–income typology has yet to be applied to the question of prediction, and thus, it remains to be seen whether these concepts will be of use in identifying the likely responses of different populations to changes in their environment.

An aspect of life history that has seen increasing attention in recent years is that of strategies for financing the costs of offspring production. These strategies are often described by a continuum ranging from capital breeding, in which costs are met purely from endogenous reserves, to income breeding, in which costs are met purely from concurrent intake. A variety of factors that might drive strategies toward a given point on the capital-income continuum has been reviewed, and assessed using analytical models. However, aspects of food supply, including seasonality and unpredictability, have often been cited as important drivers of capital and income breeding, but are difficult to assess using analytical models. Consequently, we used dynamic programming to assess the role of the food supply in shaping offspring provisioning strategies. Our model is parameterized for a pinniped (one taxon remarkable for the range of offspring-provisioning strategies that it illustrates). We show that increased food availability, increased seasonality, and, to a lesser extent, increased unpredictability can all favor the emergence of capital breeding. In terms of the conversion of energy into offspring growth, the shorter periods of care associated with capital breeding are considerably more energetically efficient than income breeding, because shorter periods of care are associated with a higher ratio of energy put into offspring growth to energy spent on parent and offspring maintenance metabolism. Moreover, no clear costs are currently associated with capital accumulation in pinnipeds. This contrasts with general assumptions about endotherms, which suggest that income breeding will usually be preferred. Our model emphasizes the role of seasonally high abundances of food in enabling mothers to pursue an energetically efficient capital-breeding strategy. We discuss the importance of offspring development for dictating strategies for financing offspring production.

In areas of high infection prevalence, effective control of schistosomiasis – one of the most important Neglected Tropical Diseases – requires supplementing medical treatment with interventions targeted at the environmental reservoir of disease. In addition to provision of clean water, reliable sanitation, and molluscicide use to control the obligate intermediate host snail, top-down biological control of parasite-competent snails has recently gained increasing interest in the scientific community. However, evidence that natural predators can effectively reduce snail abundance and, ultimately, transmission risk to vulnerable human populations remains limited. In this study, we used a Before-After-Control-Intervention (BACI) design implemented in seven lakeside areas, including three intervention areas and four control areas, on the southern shores of Lake Victoria (Tanzania) in 2019–2023. We tested whether the restoration of African catfish, Clarias gariepinus , a native species of commercial value, could reduce both the abundance of Biomphalaria snails (intermediate hosts of Schistosoma mansoni ) and infection intensity in school age children (SAC). Where catfish were restored, mean site-level snail counts declined by 57% (95% CI: 29.4%, 74.3%). At primary schools located within each area, SAC infection intensity (mean parasite egg count in stool samples) also decreased significantly by 55% (95% CI: 26%, 73%). This study shows that natural predators of host snails have the potential for schistosomiasis control. Scaling up to a lake-wide approach will require systemic intervention, with snail host control contributing to a broader framework for schistosomiasis management.

The lower legislative chamber of the United Kingdom's Parliament has 650 members, but only one (0.15%) has a science Ph.D. This seems like a surprisingly small number in a mature democracy. About 0.8% of people in the United Kingdom have a science Ph.D., so it appears that science is seriously underrepresented. I suspect it is the same the world over. Why is this, is it right, and what are the consequences?

Can lessons from pharmaceutical monitoring help to improve pesticide regulation? Agricultural pesticides are an important component of intensive agriculture and, therefore, of global food production. In the European Union, ∼500 active substances used in pesticides are approved, including insecticides, fungicides, herbicides, and plant growth regulators. When used at industrial scales, pesticides can harm the environment ( 1 ), but there is a trade-off between this effect and the need to produce food. Recent uncertainties about the health and environmental effects of glyphosate herbicide and neonicotinoid insecticides underline the need for regulation to be sensitive to this trade-off ( 2 , 3 ). Better regulation is needed to control how pesticides are used and affect the environment at a landscape scale.

Beaked whales have mass stranded during some naval sonar exercises, but the cause is unknown. They are difficult to sight but can reliably be detected by listening for echolocation clicks produced during deep foraging dives. Listening for these clicks, we documented Blainville's beaked whales, Mesoplodon densirostris, in a naval underwater range where sonars are in regular use near Andros Island, Bahamas. An array of bottom-mounted hydrophones can detect beaked whales when they click anywhere within the range. We used two complementary methods to investigate behavioral responses of beaked whales to sonar: an opportunistic approach that monitored whale responses to multi-day naval exercises involving tactical mid-frequency sonars, and an experimental approach using playbacks of simulated sonar and control sounds to whales tagged with a device that records sound, movement, and orientation. Here we show that in both exposure conditions beaked whales stopped echolocating during deep foraging dives and moved away. During actual sonar exercises, beaked whales were primarily detected near the periphery of the range, on average 16 km away from the sonar transmissions. Once the exercise stopped, beaked whales gradually filled in the center of the range over 2-3 days. A satellite tagged whale moved outside the range during an exercise, returning over 2-3 days post-exercise. The experimental approach used tags to measure acoustic exposure and behavioral reactions of beaked whales to one controlled exposure each of simulated military sonar, killer whale calls, and band-limited noise. The beaked whales reacted to these three sound playbacks at sound pressure levels below 142 dB re 1 µPa by stopping echolocation followed by unusually long and slow ascents from their foraging dives. The combined results indicate similar disruption of foraging behavior and avoidance by beaked whales in the two different contexts, at exposures well below those used by regulators to define disturbance.

The post-truth politics of 2016 has made it a difficult year for those of us who like to see decisions guided by evidence. As a chief scientific adviser to the UK government, I would caution against any disengagement by the science community from policymaking. Science remains an integral part of the processes of government, and its outputs are increasingly needed.

This study investigated the degree to which the behavior of a predator in the marine environment can be used to indicate the availability of prey. It examined this in Antarctic fur seals (Arctocephalus gazella) feeding on krill, with a view to understanding how behavioral choices could lead to a nonlinear functional response. The study showed how fur seals adjusted their time budgets to maximize the mean rate of energy intake in response to varying prey abundance. The behavioral indicator of prey abundance was the amount of time spent by fur seals at the bottom of dives after adjustment for dive depth. This indicator was well correlated with independent measures of prey abundance. The indicator was calibrated in terms of net rate of energy intake from information about energy expenditures in Antarctic fur seals and was used within the framework of optimal foraging theory to examine how female fur seals organized their foraging activity within and between bouts. Foraging in Antarctic fur seals conformed to many of the predictions from energy rate-maximizing behavior. For example, the apparent net rate of energy intake by fur seals declined with time spent in a patch, and the rate of energy intake on leaving a patch declined as apparent food availability in the environment declined. In addition, the time spent in patches increased as apparent food availability declined. Antarctic fur seals were able to adjust their behavior to track highly variable prey distributions and densities. The simple decision about when to leave a patch in relation to current environmental prey availability appears to be responsible for allowing fur seals to maintain saturation of the foraging rate as food density declines.

We measured daily energy expenditure (DEE) continuously for a whole year in a free ranging bird, the macaroni penguin Eudyptes chrysolophus. We combined these measurements with concurrently recorded foraging behaviour, and literature information on body mass and dietary factors to estimate prey consumption rates and foraging success. DEE was at a maximum during late chick-rearing but was equally high during all other active phases of the breeding season. DEE was approximately 4xresting metabolic rate, which accords with established theory and suggests a common 'energetic ceiling' throughout the summer period. However, whether this represents a maximum in physiological capacity, or a rate which optimises fitness is still unclear. Rates of prey consumption and foraging success followed different patterns from daily energy expenditure. Daily prey consumption was high as the penguins prepared for long fasts associated with moulting and incubation but relatively low during chick-rearing, when foraging areas were restricted and foraging success lower. It appears that the energy intake of macaroni penguins is subject to extrinisic or environmental constraints rather than to intrinsic physiological limits.