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There is concern that overfishing may lead to a proliferation of jellyfish through a process known as fishing down the food web. However, there has been no global synthesis of patterns of gelatinous zooplankton biomass (GZB), an important first step in determining any future trends. A meta-analysis of epipelagic-GZB patterns was undertaken, encompassing 58 locations on a global scale, and spanning the years 1967-2009. Epipelagic-GZB decreased strongly with increasing total water column depth (r.sup.2 = 0.543, p < 0.001, n = 58): in shallow (2,000 m) sites. However, the ratio of GZB to primary productivity showed high values across a range of depths, i.e. this measure of the relative abundance of gelatinous zooplankton did not co-vary with depth., Author(s): M. K. S. Lilley [sup.1] , S. E. Beggs [sup.2] , T. K. Doyle [sup.3] , V. J. Hobson [sup.1] , K. H. P. Stromberg [sup.4] , G. C. [...]

The advent of Fastloc-GPS is helping to transform marine animal tracking by allowing the collection of high-quality location data for species that surface only briefly. We show how the improved location accuracy of Fastloc-GPS compared to Argos tracking is expected to lead to far more accurate home range estimates, particularly for animals moving over the scale of a few km. We reach this conclusion using simulated data and home range estimates derived from empirical tracking data for green sea turtles (Chelonia mydas) equipped with Argos linked Fastloc-GPS tags at three different foraging areas (western Indian Ocean, Western Australia, and Caribbean). Poor-quality Argos locations (e.g., location classes A, B) produced home range estimates ranging from 10 to 100 times larger than those derived from Fastloc-GPS data, whereas high-quality Argos locations (location classes 1-3) produced home range estimates that were generally comparable to those derived from Fastloc-GPS data. However, the limited number of Argos class 1-3 locations obtained for all three turtles-an average of 14.6 times more Fastloc-GPS locations were obtained compared to Argos class 1-3 locations-resulted in blurred patterns of space use. In contrast, the high volume of Fastloc-GPS locations revealed fine-scale movements in striking detail (i.e., use of discrete patches separated by just a few 100 m). We recommend careful consideration of the effects of location accuracy and data volume when developing sampling regimes for marine tracking studies and make recommendations regarding how sampling can be standardized to facilitate meaningful spatial and temporal comparisons of space use., Author(s): J. A. Thomson [sup.1] , L. Börger [sup.2] , M. J. A. Christianen [sup.3] [sup.4] , N. Esteban [sup.2] , J.-O. Laloë [sup.1] , G. C. Hays [sup.1] Author [...]

Byline: G. C. Hays (1), F. Glen (1), A. C. Broderick (1), B. J. Godley (1), J. D. Metcalfe (2) Abstract: We used time-depth recorders to measure depth utilisation in gravid green turtles (Chelonia mydas) during the internesting period at northern Cyprus (Mediterranean), a nesting area where individuals feed, and at Ascension Island (mid-Atlantic), a nesting area where individuals fast. There were contrasting patterns of depth utilisation between the two sites, illustrating that the behaviour of this species is shaped by local conditions. For example, the amount of time spent shallower than 4 m was 90% at Cyprus but only 31% at Ascension Island, and there was a clear difference between the mean depth at Cyprus (2.7 m, n=9 internesting intervals) versus Ascension Island (9.5 m, n=6 internesting intervals) (t .sub.5=5.92, P=0.002). At Cyprus, turtles spent the greatest percentage of their time at very shallow depths, where surveys reveated a high abundance of seagrass on which this population feeds. In contrast, the deeper distribution at Ascension Island may reflect the preferred depth for resting on the seabed. Author Affiliation: (1) School of Biological Sciences, University of Wales Swansea, Singleton Park, SA2 8PP, Swansea, UK (2) The Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory, NR33 0HT, Lowestoft, UK Article History: Registration Date: 31/03/2002 Received Date: 16/01/2002 Accepted Date: 29/04/2002 Article note: Published online: 23 July 2002 Communicated by G.F. Humphrey, Sydney

Research has been conducted on the male green turtles. The use of the satelite telemetry in investigating the movements and submergence behaviour of these turtles on their mating ground at Ascension Island is described and the results indicate that at the end of their mating ground residence they conduct long dives to rest before the migration away from the island.