Marine Debris Project Final Report 2014

As human population growth continues, so too does our waste, often with unintended consequences forwildlife. The estimated 640,000 tons of fishing gear lost, abandoned, or discarded annually exerts a largebut uncertain impact on marine species. These derelict fishing nets or “ghostnets” drift in the ocean andcan fish unattended for decades (ghost fishing), killing untold numbers of commercially valuable orthreatened species. We developed an integrated analysis combining physical models of oceanic drift withecological data on marine turtle species distribution and vulnerability to make quantitative predictions ofthreat. Using data from beach cleanups and fisheries in northern Australia, we assessed this biodiversitythreat in an area where high densities of ghostnets encounter globally threatened turtles. Entanglementrisk was well-predicted by our model, and was verified using independent strandings data from the region.We were able to also identify a number of previously unknown high-risk areas. From our work we were arealso able to recommend efficient locations for surveillance and interception of abandoned fishing gear. Ourwork points the way forward for understanding the global threat from marine debris and makingpredictions that can guide regulation, enforcement, and conservation action. See Appendix A for thispublished work (Wilcox et al. 2013).6.3 Pinnipeds and entanglementPrevious studies of pinnipeds in Australian waters have found that seals are vulnerable to entanglement inmarine debris (Page, et al. 2004; Pemberton, et al. 1992; Shaughnessy, et al. 2000). Entanglement occurswhen two items are entwined together and may range from single hooks to full body entanglements(Department of the Environment, 2014a). In order of severity, some of the known examples ofentanglement impacts include wounding, causing infection, maiming, amputation, restricted movement,smothering or choking of the animal leading to starvation, reduced fitness, and drowning (Department ofthe Environment 2014b).Pinnipeds are found in nearshore waters around the Australian coast from Victoria to Tasmania and acrossthe south of the continent into South Australia. Large breeding colonies of Australian fur seals occur alongthe Victorian coastline near Phillip Island. To better understand the frequency and impact of marine debrisentanglement on Australian wildlife, we collaborated with researchers from Phillip Island Nature Parks toask questions about seal entanglement. We focused our efforts on two islands in Bass Strait, Seal Rockwhich is located only 1.5 km from Phillip Island and comprises two small islands and Lady Julia Percy Islandwhich is approximately 6km off the Southern Victorian coastline in Australia. We worked with datacollected from more than 100 items in which Australian fur seals had been entangled and which were36 | Understanding the effects of marine debris on wildlife