The widespread depletion of commercially exploited marine living resources is often seen as a general failure of management and results in criticism of contemporary management procedures. When populations show dramatic and positive changes in population size, this invariably leads to questions about whether favorable climatic conditions or good management (or both) were responsible. The Barents Sea cod (Gadus morhua) stock has recently increased markedly and the spawning stock biomass is now at an unprecedented high. We identify the crucial social and environmental factors that made this unique growth possible. The relationship between vital rates of Barents Sea cod stock productivity (recruitment, growth, and mortality) and environment is investigated, followed by simulations of population size under different management scenarios. We show that the recent sustained reduction in fishing mortality, facilitated by the implementation of a "harvest control rule," was essential to the increase in population size. Simulations show that a drastic reduction in fishing mortality has resulted in a doubling of the total population biomass compared with that expected under the former management regime. However, management alone was not solely responsible. We document that prevailing climate, operating through several mechanistic links, positively reinforced management actions. Heightened temperature resulted in an increase in the extent of the suitable feeding area for Barents Sea cod, likely offering a release from density-dependent effects (for example, food competition and cannibalism) through prolonged overlap with prey and improved adult stock productivity. Management and climate may thus interact to give a positive outlook for exploited high-latitude marine resources.gadoids | population dynamics | quota | ocean warming | polar displacement

Criteria from the World Conservation Union (IUCN) have been used to classify marine fish species as endangered since 1996, but deep-sea fish have not so far been evaluated--despite their vulnerability to aggressive deepwater fishing as a result of certain life-history traits. Here we use research-survey data to show that five species of deep-sea fish have declined over a 17-year period in the Canadian waters of the northwest Atlantic to such an extent that they meet the IUCN criteria for being critically endangered. Our results indicate that urgent action is needed for the sustainable management of deep-sea fisheries.

14Trait evolution over time periods spanning generations, not millennia, is increasingly 15 observed to be above the natural baseline in populations experiencing human-induced 16 perturbations. We investigated the relative speed of trait change by comparing rates of 17 evolution in haldanes and darwins for primarily size at maturation as measured by 18 probabilistic maturation reaction norm midpoints for fish stocks from the Pacific, North 19 Atlantic, Barents Sea, Eastern Baltic, and the North Sea. Rates in haldanes for 23 stocks 20 ranged from -2.2-0.9 and from 0.5-153 in kdarwins for 26 stocks. The highest rates of 21 evolution corresponded to the most heavily exploited stocks; rates slowed after moratoria 22 were introduced. The estimated rates in fish life-history characteristics were comparable to 23 other examples of human-induced evolution, and faster than naturally-induced rates. Stocks 24 with high growth showed slower evolutionary change, even under high mortality, suggesting 25 that compensatory somatic growth can slow the rate of trait evolution. Regardless of whether 26 trait changes are due to exploitation or environmental factors, the costs of ignoring trait 27 evolution are high. As management strategies should be based upon precautionary principles, 28 the effect of changing traits must be integrated into the fisheries assessment process. 29 30

SUMMARY1. Nitrogen (N) and phosphorus (P) fluxes via excretion by benthic invertebrates were quantified in a eutrophic reservoir (Acton Lake, Ohio, U.S.A.). We quantified variation in nutrient fluxes seasonally (June until November 1997), spatially (three sites) and among taxa (chironomids, tubificid oligochaetes and Chaoborus). 2. The three taxa differed in spatial distribution and contribution to nutrient fluxes. Tubificids were the most abundant taxon at two oxic sites (1.5 and 4 m depth), and were exceedingly rare at an anoxic, hypolimnetic site (8 m). Chironomids were abundant only at the shallowest oxic site. Chaoborus was the only abundant taxon at the anoxic site. Total benthic invertebrate biomass was greatest at the shallowest site and lowest at the anoxic, hypolimnetic site. 3. Mass-specific excretion rate [lmol NH 4 -N or soluble reactive P (SRP) excreted mg dry mass -1 h -1 ] varied among experiments and was influenced by temperature. Differences among taxa were not significant. Thus, nutrient flux through benthic invertebrates was affected more by total invertebrate biomass and temperature than by species composition. 4. Fluxes of N and P via benthic invertebrate excretion (lmol NH 4 -N or SRP m -2 day -1 )were greatest at the oxic sites, where fluxes were dominated by the excretion of tubificids and chironomids. The N and P fluxes at the anoxic site were much lower, and were dominated by excretion by Chaoborus. The ratio of N and P excreted by the benthic invertebrate assemblage varied seasonally and was lowest at the anoxic site. 5.Comparison with other measured inputs shows that excretion by benthic invertebrates could be an important source of nutrients, especially of P. However, the relative importance of nutrient excretion by the benthos varies greatly spatially and temporally.