Conservation hotspots : implications of intense spatial area use by breeding male and female loggerheads at the Mediterranean’s largest rookery

The implementation of appropriate protection measures for endangered species in protected areas requires knowledge of their fine-scale habitat use. In May and June of 2006 and 2007, we used GPS loggers (some linked to the Argos system) and a conventional Argos transmitter to track male and female loggerhead turtles Caretta caretta in the vicinity of the breeding area of Laganas Bay within the National Marine Park of Zakynthos, Greece. We obtained (1) 9681 useable locations (mean: 1383 locations ind.–1; range: 519 to 2198 locations) from Tracktag GPS loggers attached to 7 females for a mean duration of 34 d (range: 17 to 52 d); (2) 1245 useable locations (mean: 311 locations ind.–1; range: 38 to 1110 locations) from 4 males fitted with Fastloc Argos tags for a mean duration of 29 d (range: 3 to 51 d) and (3) 100 locations from 1 male fitted with a conventional Argos satellite tag tracked for 128 d. GPS data indicated that before the onset of nesting, both males and females primarily used an area within 500 m of the shore along a core 9 km stretch of coastline, where existing protective legislation requires strengthening. Our observations suggest that a 76.7% female-biased operational sex ratio, measured previously from in-water surveys, may represent a realistic sex ratio estimate in the period before nesting starts. In the first month following the onset of nesting, female spatial distribution remained similar, whereas most males departed for distant areas presumably to forage. Our study provides quantitative evidence of the need to improve the management planning and conservation measures to protect sea turtles in a coastal breeding area, and new insights on male turtle migration

Accumulation of nanoparticles in " jellyfish " mucus: a bio-inspired route to decontamination of nano-waste

International audienceThe economic and societal impacts of nano-materials are enormous. However, releasing such materials in the environment could be detrimental to human health and the ecological biosphere. Here we demonstrate that gold and quantum dots nanoparticles bio-accumulate into mucus materials coming from natural species such as jellyfish. One strategy that emerges from this finding would be to take advantage of these trapping properties to remove nanoparticles from contaminated water

Inter-annual variability in the home range of breeding turtles : implications for current and future conservation management

We assessed home range size for breeding loggerhead turtles (Caretta caretta) near the limit of the species range at the Greek island of Zakynthos in the Mediterranean. Thirteen adult females and seven adult males were tracked using GPS units (loggers and transmitters) during May and June of 2006, 2007 and 2008. Kernel analysis indicated that core home range sizes (50% estimator; range: 2.9-19.7 km(2)) for both males and females were restricted to a 7.5 km tract of coastline. 15% of GPS locations fell outside of the national park protection zones, while within the protected breeding area 88% of GPS locations occurred in zones of minimal protection. Female home ranges were 64% larger in 2008 than in 2006 and 2007, indicating that several years monitoring may be required for the most effective designation of marine protected areas (MPAs). Ten of the tracked females departed the core breeding area on 15 occasions for periods of 1-15 days travelling distances of 10-100 km, although none nested at alternative breeding sites. The inter-annual variability of breeding area home range size and likelihood of incidence of forays appeared be correlated with barometric pressure. The movement responses of loggerheads to environmental conditions implicates an ability to switch nesting areas over small scales in response to climate change. However, such behaviour suggests the protection of existing core breeding sites may be inadequate, with policy makers being required to consider the protection of broader areas to encompass potential changes in the habitat needs of this species

Occurrence, characteristics and formation mechanisms of methane generated micro-pockmarks in Dunmanus Bay, Ireland

A small gas pockmark field in Dunmanus Bay, SW Ireland was surveyed and ground-truthed to assess its activity, geomorphology, explore its formation mechanisms and to investigate its potential influence on the benthic community. The field consisted of 121 circular, shallow units ranging from 5 to 17 m in diameter and not exceeding 1 m in relief. Sub-bottom profiles revealed broad acoustic signatures typical of shallow gas accumulation in the subsurface in addition to vertically elongated signals of ascending bubbles captured in the echo sounder data. The pockmarks show strong correlation with the depth of sub-surface gas fronts. However methane concentrations in the water column and directly above the features were close to typical marine, background values and did not exceed 15 nM. This suggests a very mild, periodic venting scenario. Sediment core samples revealed permeable sandy layers with slightly elevated methane concentrations indicative of stratified, diffusive flow. Pore-water sulphate and chloride data show no sign of pore water freshening and thus suggest that methane gas is the sole fluid responsible for formation of these pockmarks. Benthic infauna distributions showed reduced diversity in pockmarked regions, primarily influenced by the sediment composition. Few species utilising chemosymbiotic associations were identified, and there was little indication of a community influenced by methane venting in Dunmanus Bay

Evidence-based marine protected area planning for a highly mobile endangered marine vertebrate

Marine Protected Areas (MPAs) now form an important part of marine conservation and fisheries management; hence, there is broad interest in developing procedures that optimize their design. We used data collected over a 10-year period (2003–2012) from direct surveys and >100 adult male and female loggerhead sea turtles (Caretta caretta ) tracked with devices, includ ing GPS loggers and Fastloc GPSArgos, to consider the optimum design for a MPA at a globally important breeding area, where there is already an existing national marine park aiming to protect the population (Zakynthos, Greece). Turtles primarily used areas very close to shore (approx. 7 km in length by 1 km in width, within the <10 m isobath) for breeding and foraging activity at different times of the year. We calculated that this small nearshore coastal zone encompassed 72% of all turtle GPS locations recorded in the MPA, and is therefore important for conservation management. We developed an index to evaluate the suitabili ty of the existing and proposed conserv ation zones based on (1) home range area use by turtles in these zones versus (2) zone size, so that the benefit to turtles could be maximized while minimizing the negative impacts to other stakeholders (e.g., boat operators). With this evidence-based approach, we propose a modification to the existing MPA that might both enhance local economic tourism activities and better safeguard this key sea turtle breeding population. The approaches used here will have general application for the design of MPAs used by mobile species that can be tracked

High activity and Levy searches : jellyfish can search the water column like fish

Over-fishing may lead to a decrease in fish abundance and a proliferation of jellyfish. Active movements and prey search might be thought to provide a competitive advantage for fish, but here we use data-loggers to show that the frequently occurring coastal jellyfish (Rhizostoma octopus) does not simply passively drift to encounter prey. Jellyfish (327 days of data from 25 jellyfish with depth collected every 1 min) showed very dynamic vertical movements, with their integrated vertical movement averaging 619.2 m d&minus;1, more than 60 times the water depth where they were tagged. The majority of movement patterns were best approximated by exponential models describing normal random walks. However, jellyfish also showed switching behaviour from exponential patterns to patterns best fitted by a truncated L&eacute;vy distribution with exponents (mean &mu; = 1.96, range 1.2&ndash;2.9) close to the theoretical optimum for searching for sparse prey (&mu;opt &asymp; 2.0). Complex movements in these &lsquo;simple&rsquo; animals may help jellyfish to compete effectively with fish for plankton prey, which may enhance their ability to increase in dominance in perturbed ocean systems

The Shadow of the Bomb:a study of degree-level nuclear physics textbooks

The author presents a textual analysis of 57 nuclear physics textbooks for senior-level physics degree students. The work investigates how the textbooks relate to an aspect that is relevant and important but almost wholly avoided, namely nuclear weapons. Most of the books do, however, contain expositions of other applications, notably nuclear power reactors. These expositions are often enthusiastic and occasionally extravagant. When the existing apocalyptic arsenals are borne in mind, the textbooks' asymmetry is seen to be problematic. The publication dates of the textbooks range from 1950 to 2010, yet for the question addressed in this study remarkably little has changed. This study emphasises the culture in which we all live, rather than individual specialists. The author concludes that a response to our nuclear situation, based on a rational programme for long-term survival, rather than on psychological defences, has to come from all. Experts do have special responsibilities but the author maintains that it is unrealistic to expect specialist groups, such as those involved in producing textbooks, to act independently of the wider culture