What goes in, must come out:combining scat-based molecular diet analysis and quantification of ingested microplastics in a marine top predator

Context: Microplastics (plastic particles &lt;5 mm in size) are highly available for ingestion by a wide range of organisms, either through direct consumption or indirectly, via trophic transfer, from prey to predator. The latter is a poorly understood, but potentially major, route of microplastic ingestion for marine top predators.Approach: We developed a novel and effective methodology pipeline to investigate dietary exposure of wild top predators (grey seals; Halichoerus grypus) to microplastics, by combining scat-based molecular techniques with a microplastic isolation method. We employed DNA metabarcoding, a rapid method of biodiversity assessment, to garner detailed information on prey composition from scats, and investigated the potential relationship between diet and microplastic burden.Results: Outcomes of the method development process and results of both diet composition from metabarcoding analysis and detection of microplastics are presented. Importantly, the pipeline performed well and initial results suggest the frequency of microplastics detected in seal scats may be related to the type of prey consumed. Conclusions: Our non-invasive, data rich approach maximises time and resource-efficiency, while minimising costs and sample volumes required for analysis. This pipeline could be used to underpin a much-needed increase in understanding of the relationship between diet composition and rates of microplastic ingestion in high trophic-level species.<br/

Shear Stiffness of Pallet Rack Upright Frames

PaIIet racks, often fabricated using cold-formed steel, are used for the storage of goods. Uprights of these racks are braced in the cross-aisle direction forming a frame, which behaves like a built-up column. Evaluation of the shear stiffness of this frame is needed to determine the buckling load. Currently two approaches prevail in the rack industry to determine the shear stiffness. The RMI code uses a theoretical formula and the FEM code requires testing. There is a considerable difference in the stiffness values determined by two approaches. The present paper describes experimental and numerical studies conducted at Oxford Brookes University to evaluate shear stiffness in an ongoing research project

Estatus de las tortugas marinas en Montserrat (Caribe oriental)

The status of marine turtles in Montserrat (Eastern Caribbean) is reviewed following five years of monitoring (1999–2003). The mean number of nests recorded during the annual nesting season (June–October) was 53 (± 24.9 SD; range: 13–43). In accordance with earlier reports, the nesting of hawksbill (Eretmochelys imbricata) and green (Chelonia mydas) turtles was confirmed on several beaches around the island. Only non–nesting emergences were documented for loggerhead turtles (Caretta caretta) and there was no evidence of nesting by leatherback turtles (Dermochelys coriacea); however, it is possible that additional survey effort would reveal low density nesting by these species. Officially reported turtle capture data for 1993–2003 suggest that a mean of 0.9 turtle per year (± 1.2 SD; range: 0–4) were landed island–wide, with all harvest having occurred during the annual open season (1 October to 31 May). Informed observers believe that the harvest is significantly under–reported and that fishermen avoid declaring their catch by butchering turtles at sea (both during and outside the open season). Of concern is the fact that breeding adults are potentially included in the harvest, and that the open season partially coincides with the breeding season. The present study has shown that although Montserrat is not a major nesting site for sea turtles, it remains important on a regional basis for the Eastern Caribbean.Se ha estudiado la situación de las tortugas marinas en Montserrat (Caribe oriental) mediante un seguimiento de cinco años (1999–2003). El número medio de nidos registrados durante la estación anual de nidificación (junio–octubre) fue de 53 (± 24.9 SD; rango: 13–143). En concordancia con informes anteriores, se confirmó la nidificacón de las tortugas carey (Eretmochelys imbricata) y verde (Chelonia mydas) en varias playas alrededor de la isla. En la tortuga boba (Caretta caretta) sólo se registraron salidas sin nidificación, y no se encontraron pruebas de que la tortuga laúd (Dermochelys coriacea) nidificase; sin embargo, es posible que ulteriores estudios pongan de manifiesto una baja densidad de nidificación de esta especie. Los datos oficiales de capturas de tortugas (1993–2003) sugieren que en toda la isla llegaban a tierra una media de 0.9 tortugas anuales (± 1.2 SD; rango: 0–4), produciéndose todas las capturas cuando se había levantado la veda. Observadores bien documentados creen que las cifras de recolección están significativamente falseadas a la baja, y que los pescadores evitan declarar sus capturas sacrificando las tortugas en el mar (con la veda abierta o cerrada). Es preocupante que en esta caza puedan incluirse tortugas que crían, y que el período de captura permitida coincide en parte con la estación reproductora. Este estudio demuestra que aunque Montserrat no es un lugar principal de nidificación de las tortugas marinas, sigue siendo importante a escala regional en el Caribe oriental

Cross-aisle Stiffness Tests on Rack Upright Frames

The US Rack Manufacturers Institution (RMI) code uses a theoretical formula derived by Timoshenko and the new Eurocode EN15512 requires testing. There is a considerable difference in the stiffn ess values determined by two approaches. This paper describes the experiments conducted on 80 full sized upright frames at Oxford Brookes University varying upright size, number of panels in the frame, aspect ratio of the panel (panel length/depth), restraints at the intermediate nodes of the frame, loading pattern, lacing pattern (channels back to back or front to front) and bolt tightness. The experimental data reported can be used in proposing revised design procedures

Remote electronic monitoring as a potential alternative to on-board observers in small-scale fisheries

This is the final version of the article. Available from Elsevier via the DOI in this record.Small-scale fisheries can greatly impact threatened marine fauna. Peru's small-scale elasmobranch gillnet fishery captures thousands of sharks and rays each year, and incidentally captures sea turtles, marine mammals and seabirds. We assessed the ability of a dedicated fisheries remote electronic monitoring (REM) camera to identify and quantify captures in this fishery by comparing its performance to on-board observer reports. Cameras were installed across five boats with a total of 228 fishing sets monitored. Of these, 169 sets also had on-board fisheries observers present. The cameras were shown to be an effective tool for identifying catch, with > 90% detection rates for 9 of 12 species of elasmobranchs caught. Detection rates of incidental catch were more variable (sea turtle = 50%; cetacean = 80%; pinniped = 100%). The ability to quantify target catch from camera imagery degraded for fish quantities exceeding 15 individuals. Cameras were more effective at quantifying rays than sharks for small catch quantities (x ≤ 15 fish), whereas size affected camera performance for large catches (x > 15 fish). Our study showed REM to be effective in detecting and quantifying elasmobranch target catch and pinniped bycatch in Peru's small-scale fishery, but not, without modification, in detecting and quantifying sea turtle and cetacean bycatch. We showed REM can provide a time- and cost-effective method to monitor target catch in small-scale fisheries and can be used to overcome some deficiencies in observer reports. With modifications to the camera specifications, we expect performance to improve for all target catch and bycatch species.This work was supported by the Darwin Initiative Project EIDP0046 and the Whitley Fund for Nature Grant 150626 CF15. David C. Bartholomew is supported by a NERC studentship NE/L002434/1

Oceanic long-distance navigation : do experienced migrants use the earth\u27s magnetic field?

Albatrosses and sea turtles are known to perform extremely long-distance journeys between disparate feeding areas and breeding sites located on small, isolated, oceanic islands or at specific coastal sites. These oceanic journeys, performed mainly over or through apparently featureless mediums, indicate impressive navigational abilities, and the sensory mechanisms used are still largely unknown. This research used three different approaches to investigate whether bi-coordinate navigation based on magnetic field gradients is likely to explain the navigational performance of wandering albatrosses in the South Atlantic and Indian Oceans and of green turtles breeding on Ascension Island in the South Atlantic Ocean. The possibility that magnetic field parameters can potentially be used in a bi-coordinate magnetic map by wandering albatrosses in their foraging area was investigated by analysing satellite telemetry data published in the literature. The possibilities for using bi-coordinate magnetic navigation varied widely between different areas of the Southern Oceans, indicating that a common mechanism, based on a bi-coordinate geomagnetic map alone, was unlikely for navigation in these areas. In the second approach, satellite telemetry was used to investigate whether Ascension Island green turtles use magnetic information for navigation during migration from their breeding island to foraging areas in Brazilian coastal waters. Disturbing magnets were applied to the heads and carapaces of the turtles, but these appeared to have little effect on their ability to navigate. The only possible effect observed was that some of the turtles with magnets attached were heading for foraging areas slightly south of the control turtles along the Brazilian coast. In the third approach, breeding female green turtles were deliberately displaced in the waters around Ascension Island to investigate which cues these turtles might use to locate and return to the island; the results suggested that cues transported by wind might be involved in the final stages of navigation