Climate drives the geography of marine consumption by changing predator communities

Este artículo contiene 7 páginas, 3 figuras, 1 tabla.The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats. This pattern contrasts with terrestrial systems, where biotic interactions reportedly weaken away from the equator, but it parallels an emerging pattern of a subtropical peak in marine biodiversity. The higher consumption at midlatitudes was closely related to the type of consumers present, which explained rates of consumption better than consumer density, biomass, species diversity, or habitat. Indeed, the apparent effect of temperature on consumption was mostly driven by temperature-associated turnover in consumer community composition. Our findings reinforce the key influence of climate warming on altered species composition and highlight its implications for the functioning of Earth’s ecosystems.We acknowledge funding from the Smithsonian Institution and the Tula Foundation.Peer reviewe

Effects of spatial structure on stock assessment estimates of biomass and productivity for Yelloweye rockfish (Sebastes ruberrimus) in British Columbia

Ignoring the underlying structure of populations can lead to sub-optimal management of fisheries resources. I examined the influence of spatial population structure assumptions on stock assessment estimates of biomass and productivity for Yelloweye rockfish in British Columbia, Canada. Delay-difference assessment models were fit to different scenarios in which discrete stocks were delineated at successively smaller spatial scales. My results show that, in some scenarios, uncertainty in stock assessment outputs was no greater at finer spatial scales than for the aggregate stock. There was also evidence of differences in stock status at finer scales, suggesting that it might be worthwhile to establish methods for tracking Yelloweye on a finer spatial scale. Comparisons between the aggregated, coast-wide stock, and disaggregated north and south assessments would allow tracking of any differences in responses to management, providing additional certainty regarding management options and potentially lead to improved outcomes for the species

Monitoring the growth and survival of larval herring on B.C. central coast

Herring spawning on British Columbia’s central coast takes place in the early spring. Strength of a year class is largely dependent on successful recruitment from the larval stage to the adult population. The potential temporal and spatial overlap of herring larval distribution with spring bloom dynamics can be a major determining factor in the success of larvae in finding suitable prey, with delayed feeding potentially leading to mass mortality. Consequently the phenology and productivity of plankton blooms, as well as the interannual variability in spawning at active sites can be significant. Reporting on data since 2012, we observe that although spawn timing does vary from year to year, this variation is less than that associated with spring bloom timing. The prey conditions experienced by larvae are therefore expected to vary significantly from one year, and site, to the next. In fact, larval growth at 38% of sites sampled wa

Climate drives the geography of marine consumption by changing predator communities

The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats. This pattern contrasts with terrestrial systems, where biotic interactions reportedly weaken away from the equator, but it parallels an emerging pattern of a subtropical peak in marine biodiversity. The higher consumption at midlatitudes was closely related to the type of consumers present, which explained rates of consumption better than consumer density, biomass, species diversity, or habitat. Indeed, the apparent effect of temperature on consumption was mostly driven by temperature-associated turnover in consumer community composition. Our findings reinforce the key influence of climate warming on altered species composition and highlight its implications for the functioning of Earth's ecosystems