Marine Debris Project Final Report 2014

terrestrial sources to coastal debris. Finally, we estimate the relative distribution of debris in the coastalmarine environment, and compare that with a set of continental scale surveys at sea.MethodsSpatial component (sites and site selection)We selected an initial survey site in the northeastern part of the continent at random and then selectedsites approximately every 100km in a clockwise fashion around Australia, using a smoothed version of thecoastline capturing the major features. Due to accessibility, in some areas we were not always able totarget selected sites exactly. In those instances we used the nearest site to which we could gain access. Inthe central region of the southern coast we were unable to carry out five surveys due to lack of access(Figure 3). Isolation varied widely among sites, with most accessible by vehicle or on foot, and theremaining sites (west coast of Tasmania, northwest coast of mainland Australia) accessed by floatplane(Figure 3). We completed a total of 575 transects at 122 coastal sites around Australia though we have agap in the northernmost part of the continent (Figure 1). Surveys took place between October 2011 andMay 2013.Surveys were conducted according to a stratified random sampling approach. Upon accessing the coast, werandomly selected the direction from the access point (right or left) to where transects were conducted(except where there was insufficient coastline from the point of access. To avoid bias (e.g. the effect ofhigher traffic at the access point), wherever possible, we walked a minimum of 50 meters from the accesspoint to the location where we would conduct the first transect. Each subsequent transect was a minimumof 50 meters distant from the previous transects. Transects were distributed evenly across the range ofsubstrate types (beach, cobble, boulder, bare rock, mud, mangrove) at each site. At each site we carriedout a minimum of three transects. If debris was not found in these first three transects we continued to addtransects stratified across the habitat types until either debris was found or we reached the maximum of 6transects. Transects are 2 meters in width, with one observer each reporting all items observed for a onemeter wide swath. The two observers walk along a meter tape reporting all items observed from uprightstanding position, as per Year One report (Appendix C).24 | Understanding the effects of marine debris on wildlife