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Basking sharks Cetorhinus maximus have undergone widespread historic exploita- tion in the northeast Atlantic and are of conservation concern. A greater knowledge of their spatial and temporal habitat use is required to better inform subsequent monitoring and management strategies. Techniques such as light-based geolocation have provided great insights into individ- ual movements, but currently available data do not permit extrapolation to the population level. Public recording schemes may, however, help to fill shortfalls in data gathering, especially when analysed in conjunction with data from these other techniques. We analysed 11 781 records (from 1988 to 2008) from 2 public recording databases operating in the UK. We describe 3 sightings hotspots: western Scotland, Isle of Man and southwest England, and highlight the marked season- ality of basking shark sightings, which were at their greatest during the northeast Atlantic sum- mer (June to August). We further highlight a significant correlation between the duration of the sightings season in each year and the North Atlantic Oscillation, an atmosphereocean climate oscillation that has been linked to forcing of marine ecosystems. We augment patterns from public sightings records with effort-related data collected by boat-based transects at 2 regional sightings hotspots (western Scotland and southwest England). Analysis of reported body size data indicated that the annual proportion of small sharks ( 6 m) remained constant. These patterns may be indicative of a population recovery fol- lowing systematic harvesting in the 20th century.

Despite a powerful, federal legislative framework established to protect threatened and endangered species in the United States, conservation actions can be hindered by the complexity of the full management structure. This is particularly true when state and federal agencies share the responsibility to conserve endangered species. To illustrate this point, this paper describes the management of sea turtle by-catch in commercial fisheries within the state waters of North Carolina. It reviews past and present by-catches, summarizes state and federal efforts intended to reduce sea turtle by-catch, and discusses the challenges posed by the involvement of multiple agencies with conflicting objectives. It concludes by recommending fundamental changes to this management framework and, in particular, proposes the establishment of a multilayered stakeholder group that would work to reduce sea turtle by-catch while supporting vibrant commercial fisheries in the state.

Differential habitat use and foraging behaviors at various life-stages within a population can have profound consequences for survivorship, stage duration, and time to maturity. While evidence for plasticity within a given life-stage in marine species is mounting, factors that contribute to this diversity remain poorly understood. We used stable isotope analysis of consumer and prey tissues to describe the trophic niche width of juvenile loggerhead turtles (Caretta caretta) that have been tracked and previously shown to have significant variation in movement behaviors (oceanic versus neritic). Results of a Bayesian mixing model indicated that whereas benthic invertebrates dominated the recent diet of neritic turtles (determined through blood plasma), pelagic prey items contributed substantially to the diets of oceanic turtles. Analysis of temporally protracted diet composition (determined through red blood cells) reflected contributions from pelagic prey for all turtle groups, indicating that all turtles fed in the pelagic zone during overwintering periods. These results imply that the previous satellite tracking results reflect the turtles' prior foraging habits. Our study highlights the need for an integrative management approach of North Atlantic juvenile loggerheads and validates the use of stable isotopes for determining their differential habitat use.

article i nfo For immature animals, diet quality and composition influence expression of life history traits such as growth rates and ultimately life stage duration and age to maturity. Circumglobally distributed loggerhead turtles (Caretta caretta) exhibit a multi-decade immature stage that generally occupies neritic habitats and is characterized by slow growth and an omnivorous diet. Although adult nesting populations are geographically distinct, foraging areas for immature loggerheads show a high degree of mixing of individuals that originate from multiple nesting stocks. Furthermore, despite their generalist foraging ecology, immature loggerheads have been observed to supplement their natural diets with fish from fishery discards and/or caught in fishing gear. However, whether trophic opportunism results in variation in loggerhead growth rates within or among feeding areas has not been investigated. In Core Sound, North Carolina (NC), USA, immature loggerheads demonstrate highly variable size-specific growth rates, in contrast to other studies that report discernible somatic growth functions in immature marine turtles. To determine whether inter-individual variation in growth rates at this site was due to variation in diet composition, and specifically variation in consumption of fish, we analyzed carbon and nitrogen stable isotope ratios of loggerhead blood plasma and of tissue samples of putative loggerhead prey, as well as commercially important fish species. Our results indicated that growth rates were not related to trophic levels at which individual turtles fed, but rather probably reflected inter- individual variation in overwintering or foraging behavior (i.e. nearshore vs. offshore). Furthermore, loggerhead diets were highly diverse, and comprised mainly blue crabs and/or whelks, as well as small proportions of cannonball jellies. Fish were unimportant dietary components for loggerheads. Although loggerheads in NC do not appear to feed on fish catch or discards, immature turtles showed dietary preferences for prey items that are also valuable to or are commonly taken as bycatch in commercial fisheries (e.g. blue crabs and whelks, respectively) in the region. Thus, the status of these prey items/fishery stocks as well as trends in loggerhead populations should be monitored to mitigate potential competitive interactions between fisheries activities and loggerhead turtles.

As eutrophication of estuaries and coastal oceans increases worldwide, the resulting expansion of hypoxic zones represents an increasingly frequent form of habitat degradation. Although impacts of prolonged hypoxia on benthic invertebrate species are well-documented, there is little understanding of how those effects subsequently influence the motile upper trophic levels in estuarine ecosystems. Quantitative nekton surveys in the Neuse River Estuary and field experiments in June and August 1999 using Atlantic croaker Micropogonias undulatus demonstrated that inter- mittent hypoxia decreased habitat quality for juvenile, demersal fish through 3 pathways: (1) hypoxia restricted the fishes in estuaries to shallow, oxygenated areas, where in the early part of the summer about 1 ⁄3 fewer prey resources were available. (2) This contraction of suitable habitat crowded the fish into smaller areas and may have resulted in density-dependent reduction of growth rates. (3) Most importantly, mortality of sessile infauna in deeper areas exposed to intermittent hypoxia decreased prey densities about 8-fold between the June and August experiments. Through these mechanisms, intermittent hypoxia may result in ecological crunches or bottlenecks. Field data collected from May to October in 3 yr (1998 to 2000) with differing levels of hypoxia support the conclusion that intermit- tent hypoxia may decrease habitat quality and result in ≥50% declines in juvenile fish growth rate. Incorporation of these indirect effects of hypoxia on juvenile growth rates into a population model demonstrated the potential for significant (~4%) reductions in population growth rate. Thus, sub- lethal effects of hypoxia-driven habitat degradation may impact fisheries production not only through reduced size at age, but also through reduced abundance of demersal fish populations.

We report here the response of the water column and phytoplankton biomass of a large lagoonal estuary to a record freshwater discharge event which followed from extraordinary hurricane activity. In the fall of 1999, three hurricanes passed over eastern North Carolina coast in a 7-wk period: Hurricane Dennis (August 24–September 5), Hurricane Floyd (September 14–17), and Hurricane Irene (October 13–16). The hurricanes delivered record rainfall to the watersheds of the Pamlico Sound, North Carolina, the second largest estuary in North America. Hurricane Floyd was followed by a 500-yr flood that displaced 80% of the volume of the Sound and delivered half the annual nitrogen (N)-nutrient load to this N-limited system.