Proceedings of the Untangled symposium: - WSPA

Annex 4Submitted abstracts accompanyingposter presentationslarge-scale assessments of the distribution, abundance,and condition of benthic coral reef organisms in a varietyof subtidal, ocean-side habitats from south of Miamito Key West since 1999. A stratified random samplingdesign that incorporates multiple habitat types and areasinside and outside of no-fishing zones is used to partitionthe Florida Keys study area. Included in this programare surveys of the type, length, weight, and impacts ofmarine debris to benthic organisms, as well as removal ofencountered debris. The purpose of these surveys is notto remove as much marine debris as possible, but ratherto document the spatial distribution and amount of marinedebris and to use the stratified survey design that allowsfor estimation of the total amount of debris on the seabedfor the habitats sampled. Results from several large-scalesampling missions during the past decade indicate thatlost angling gear and lobster/crab trap gear are the mostcommon items encountered, but that marine debris ingeneral is ubiquitous throughout the ecosystem. Effortsto reduce lost fishing gear are challenging and it is likelythat entangled debris on the seabed will continue to be achronic, low-level stressor in the Florida Keys.Addressing the threat posed by marine debris towildlife in the deep oceansMark Peter SimmondsSenior Associate Marine ScientistHumane Society Internationalmark.simmonds@sciencegyre.co.ukEntanglement in marine debris raises very severe animalwelfare issues. For example, entangled marine mammalsmay struggle in discarded fishing nets for long periodsof time before they finally succumb. Efforts related toentanglement of wildlife in debris is largely focused closeinshore and on land, for example in nesting and hauloutsites. Clean-ups have focused primarily on the seashore and shallow areas accessible to snorkelers andscuba divers. However, there is evidence of the buildupof debris in some deeper offshore areas. This raisesquestions about how significant deeper accumulationsmay be, where deep sea entanglement ‘hot spots’ areand how they might be best addressed, especially giventhe difficulties posed by offshore conditions.Sampling of debris found offshore at the surface andon the deep seabed will yield evidence about sources.This would potentially allow targeting of sources, suchas certain fisheries with high levels of discards. A recentstudy in the Gulf of California using a submersible atdepths of 20-365m, found that fishing activities were thedominant contributor to debris, which was densest closeto fishing ports and consisted mainly of monofilamentfishing line. Elsewhere, bottom trawling has been usedto sample debris but this cannot be used where thebenthos is rocky or where there are wrecks, whichare both features where lost fishing gear is likely toaccumulate. Acoustic techniques (e.g. side scan sonar)might be used to examine the deep sea benthos and,although plastics are relatively transparent to acoustictechniques, imaging abilities are improving and soliddebris-ensnaring features can certainly be identified.(As sonars introduce sound into the marine environment,the cost-benefit of such approaches would need to becarefully weighed.)Efforts are also being made to model the dispersal of lostnets, although these appear to be at an early stage ofdevelopment. In addition, certain marine animal speciesmay act as indicators of what is happening in the deepseas, potentially including the deep-diving whales.Sampling and mapping of debris at the surface of theoceans is better developed and studies focused onmapping and assessing wildlife at the surface are alsoincreasingly systematically recording and mappingfloating debris. Such information could be usefullycompiled, along with reports of debris from other marineusers, into regional or international databases that mayhelp to identify offshore areas where interactions withwildlife may be concentrated.This review will explore these topics further – drawingtogether information about approaches that mightlead to the improved identification of concentrationsof entangling debris and thereby facilitating discussionaround this topic and, ultimately, remedial action.Debris in the deep seas is largely out of human sight,but the old adage of ‘out of sight and out of mind’ mustnot be allowed to apply to this cruel threat to wildlife anymore than it should relate to any other.35