Effective ocean management and conservation of highly migratory species depends onresolving overlap between animal movements and distributions, and fishing effort.However, this information is lacking at a global scale. Here we show, using a big-data approach that combines satellite-tracked movements of pelagic sharks and global fishing fleets, that 24% of the mean monthly space used by sharks falls under the footprint of pelagic longline fisheries. Space-use hotspots of commercially valuable sharks and of internationally protected species had the highest overlap with longlines (up to 76% and 64%, respectively), and were also associated with significant increases in fishing effort.We conclude that pelagic sharks have limited spatial refuge from current levels of fishing effort in marine areas beyond national jurisdictions (the high seas). Our results demonstrate an urgent need for conservation and management measures at high-seas hotspots of shark space use, and highlight the potential of simultaneous satellite surveillance of megafauna and fishers as a tool for near-real-time, dynamic management.Industrialised fishing is a major source of mortality for large marine animals (marine megafauna) 1-6 . Humans have hunted megafauna in the open ocean for at least 42,000 years 7 , but international fishing fleets targeting large, epipelagic fishes did not spread into the high seas (areas beyond national jurisdiction) until the 1950s 8 . Prior to this, the high seas constituted a spatial refuge largely free from exploitation as fishing pressure was concentrated on continental shelves 3,8 . Pelagic sharks are among the widest ranging vertebrates, with some species exhibiting annual ocean-basin-scale migrations 9 , long term trans-ocean movements 10 , and/or fine-scale site fidelity to preferred shelf and open ocean areas 5,9,11 . These behaviours could cause extensive spatial overlap with different fisheries from coastal areas to the deep ocean. On average, large pelagic sharks account for 52% of all identified shark catch worldwide in target fisheries or as bycatch 12 . Regional declines in abundance of pelagic sharks have been reported 13,14 , but it is unclear whether exposure to high fishing effort extends across ocean-wide population ranges and overlaps areas in the high seas where sharks are most abundant 5,13 .Conservation of pelagic sharkswhich currently have limited high seas management 12,15,16would benefit greatly from a clearer understanding of the spatial relationships between sharks' habitats and active fishing zones. However, obtaining unbiased estimates of shark and fisher distributions is complicated by the fact that most data on pelagic sharks come from catch records and other fishery-dependent sources 4,15,16 .Here, we provide the first global estimate of the extent of space use overlap of sharks with industrial fisheries. This is based on the analysis of the movements of pelagic sharks tagged with satellite transmitters in the Atlantic, Indian and Pacific oceans, together with fishing vessel movements m...

Sixty nine hammerhead sharks, Sphyrna lewini, were tagged at Malpelo Island (Colombia) with ultrasonic transmitters during

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While little is known about hawksbill turtles Eretmochelys imbricata in the eastern Pacific Ocean, available information suggests that the population has declined substantially in recent decades and could be near extirpation in the region. To evaluate the current status of the population more effectively and to determine the feasibility of recovery efforts, a workshop of regional marine turtle specialists was held in June 2008 in Los Cóbanos, El Salvador. An international working group, Iniciativa Carey del Pacífico Oriental (ICAPO; Eastern Pacific Hawksbill Initiative in English), was established to consolidate information, promote conservation projects and raise awareness about the species. We present information derived from the workshop and compiled by the ICAPO working group since that time. Considering only records from 1 January 2007 to 31 May 2009 it appears that El Salvador hosts the majority of known hawksbill turtle nesting activity in the eastern Pacific, with 79.6% (n = 430) of all nesting observation records, and Mexico hosts the majority of records of hawksbill turtles at sea, with 60.3% (n = 44) of all in-water observation records. Although current abundance is very low, the pervasiveness of the species in the region suggests potential for conservation and recovery. Despite a historical paucity of research focusing on this population, the relatively large and steadily increasing number of records as a result of concerted efforts demonstrates the viability of the ICAPO network as an instrument to promote conservation of this species in the eastern Pacific.

We deployed pop-off satellite archival tags (PSATs) on 14 olive ridley turtles Lepidochelys olivacea and 1 green turtle Chelonia mydas in the eastern tropical Pacific Ocean between November 2001 and June 2003 to determine dive behavior and post-release mortality following interactions with longline fishing gear. Nine olive ridleys and 1 green turtle were captured by longline fishing gear, and 5 free swimming olive ridleys were hand-captured at the surface to serve as controls. Hooks were removed from all longline-caught turtles, with the exception of 1 olive ridley turtle. PSATs remained on control-and longline-caught olive ridleys for an average of 61 and 54 d, respectively (range: 26 to 115) and on the green turtle for 26 d. Olive ridleys spent nearly all of their recorded time within the top 60 m, with very few dives exceeding 100 m. Over 95% of the time was spent between water temperatures of 22 and 28°C and turtles' dive behaviors appeared to be correlated with oceanographic variables (e.g. sea surface temperature and chlorophyll concentration). There were no clear differences evident either in horizontal movements, depth distributions, or associations with specific water temperatures between longline-caught and control turtles. Our data showed only one mortality event, that of a control turtle that died and sank 66 d after being tagged. We conclude that olive ridley turtles that are lightly hooked and handled properly survive and generally behave normally following interactions with shallow-set longline gear.

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We conducted laboratory and field experiments to investigate the behavioral responses of Kemp's ridley Lepidochelys kempii and loggerhead turtles Caretta caretta to whole squid dyed different colors. Our ultimate goal was to identify bait modifications that could reduce the interaction of turtles with longline fishing gear. In captivity, both turtle species clearly preferred untreated squid over squid that had been dyed dark blue. Loggerhead turtles also preferred untreated squid over reddyed squid, whereas Kemp's ridley showed the opposite response. Field trials of blue-dyed bait were conducted on commercial fishing boats in the Gulf of Papagayo, Costa Rica, where the incidental capture of olive ridley turtles Lepidochelys olivacea is high (long-term average, approximately 7 turtles per 1000 hooks). We found no differences in rates of turtle interactions (8.4 and 8.1 individuals per 1000 hooks) when using untreated versus blue-dyed baits. Although effective in laboratory settings with captive turtles, dyeing bait does not appear to have potential as an effective mitigation measure to reduce sea turtle bycatch in longline fisheries. KEY WORDS: Sea turtle fisheries interactions · Bait color · Sea turtle bycatch mitigationResale or republication not permitted without written consent of the publisher