Research Technical Report
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Impacts of Marine Debris Measured by Beach COMBERS: Plastic Ingestion and Entanglement in Marine Birds and Mammals
Nevins, H.M., E.L. Donnelly-Greenan, and J.T. Harvey (April 2014)
Report prepared for Monterey Bay National Marine Sanctuary, San Jose State Foundation Grant #23-1509-5151. 15p.
Marine debris can cause harmful impacts to marine birds, mammals, sea turtles and fishes (Derraik et al. 2002, Hyrenbach et al. 2013). These impacts include entanglement in lost or abandoned fishing gear, traps, balloons, and line material (Raum-Suryan et al. 2009) and ingestion of plastic fragments, foam, and other substances (Spear et al. 1995, Laist et al. 1997). Sources of potentially harmful marine debris include land-based sources (beaches, waterways, and storm runoff), ship-based sources (recreational, commercial vessel) and catastrophic events (hurricanes, typhoons, tsunamis). The March 2011 Japan Tsunami created an estimated 5 million tons of marine debris input into the North Pacific Gyre and impacts in the California Current System are expected in 2014-2016. As of April 2014, the General NOAA Operational Modeling Environment (GNOME) predicts a high concentration of tsunami-related marine debris particles 500-700 miles offshore of central California, near the out edge of the California Current.
There is a need to understand the threats from the Tsunami debris and other sources on wildlife within the Monterey Bay National Marine Sanctuary (MBNMS) to determine if there has been an increasing or decreasing trend in these impacts. By tracking these inter-annual trends in marine debris impacts to wildlife, we also hope to inform policies directed towards reducing marine debris (i.e., lost gear recovery, plastic bag and Styrofoam take-out container bans) and make recommendations for future mitigation.
Entanglement in fishing gear is a chronic source of mortality for seabirds and marine mammals in California (Moore et al. 2009). During 2001–2005, Moore et al. (2009) documented 31 bird species and nine marine mammal species. The most frequently entangled species were Common Murres (Uria aalge), Western Gulls (Larus occidentalis) and California sea lions (Zalophus californianus). The entanglement materials identified were primarily fishing related including monofilament line, hooks, and weights.
In this study, we examined beach stranding records over a longer time period (15 years) to establish the baseline rate of wildlife impacts (entanglement and ingestion) prior to significant known impacts of the 2011 Tsunami. We used records from on-going Coastal Ocean Mammal and Bird Education and Research Surveys (BeachCOMBERS) conducted by volunteers monthly in MBNMS. Since 1997, the BeachCOMBERS program has coordinated >200 volunteers to monitor human and natural impacts to coastal wildlife by documenting the deposition of marine birds, mammals, and sea turtles. This long-term monitoring program has successfully informed resource managers about wildlife impacts from oil spills, starvation, fishery interactions, and harmful algal blooms (Nevins et al. 2011).
We also present data from the Seabird Health Study a collaborative project with Oikonos Ecosystem Knowledge and CA Dept. of Fish and Wildlife (CDFW) since 2005 to document rates of plastic ingestion in seabirds. BeachCOMBERS and other rehabilitation centers throughout the Monterey Bay region participated in collecting seabird carcasses for necropsy (dissection). Nevins et al. (2005) found that the incidence of plastic ingestion in Northern Fulmars (Fulmarus glacialis) from birds collected in Monterey Bay was as high as 72% in 2003. These data will provide important pre-tsunami metrics for comparisons should the surface currents transport an increase availability of fragments to these surface-feeding birds in the coming years from sources such as the 2011 Tsunami.