Monday, November 25, 2013

Plastic for Dinner: Marine Debris and its Effects on Seabirds --Guest Post--

Plastic Dinner. Photo by Alex Bond.
    Imagine carrying around several kilos (or pounds) of plastic in your stomach, unable to rid yourself of it, and gradually adding pieces day by day.  This is what many marine animals go through every day.  Millions of pieces of plastic enter the world’s oceans each day, and once it’s there, it doesn’t go away.  Instead, it breaks into smaller and smaller pieces.  But every piece of plastic ever produced by humanity exists in some form or another today. And it will for years to come.

    Seabirds mistake floating plastic for food (pieces of squid, fish eggs, small invertebrates), and ingest them everywhere from Tristan da Cunha (the most remote island in the world; in the South Atlantic Ocean) to the Canadian Arctic.  Aside from the obvious physical damage from eating (often large) bits of plastic, plastic floating in the ocean acts like a sponge to sop up hydrophobic contaminants (those that don’t like water), like PCBs, DDT, and newer chemicals like polybrominated diphenyl ethers (PBDEs, used as flame retardants).  Once in a bird’s stomach (which is warm and acidic), the outer layers of the plastic, with the tag-along contaminants, enters the bird’s body.

Thick-billed (L) and Common Murre (R).
 Photo by Alex Bond.
    In Canada, we know very little about which species ingest plastic, in what quantities, and the influences of this behaviour.  About 2 years ago, while chatting with some colleagues in Newfoundland, someone mentioned that there were data sheets from about 1200 Thick-billed Murres (Uria lomvia) used in a study of diet in the mid-1980s.  Murres (both Thick-billed, and Common (Uria aalge)) are harvested legally in Newfoundland and Labrador each winter (and are rather delicious!).  Back in the 1980s, scientists worked with harvesters to examine the contents of murres’ stomachs, and better understand what murres ate outside the breeding season; they made note of any plastics they found.

    In the mid-1990s, some other folks did the same thing, using about 400 murres to look at what changes the 1992 groundfish moratorium had on murres’ ecology and diet. Thankfully, they also recorded ingested plastic.

    We pulled together these original datasheets, and 15-year-old spreadsheets, along with our own sampling of about 50 birds in 2011-12 to try and understand if murres’ rate of plastic ingestion had changed over time, and whether there were differences between the two species, and between adult and first-winter birds. The bottom line is that about 7-8% of murres, regardless of species or age, contain at least some plastic. And, this has been the case since the 1980s.  This is surprising for two reasons:

    First, murres dive for their food. Deep. Up to 180 m deep.  We don’t expect to find a lot of plastic there, since most of it is concentrated at the surface.

    Second, plastic production has increased over time, and so we would expect an increase in the plastics in murres, but that wasn’t the case.  In general, there was more plastic ingested in the 1980s, and less in the 1990s (our 2011-12 sample was in the middle).

    What also makes this study important is that it’s one of the few studies that have looked at changes in plastic ingestion over time (in Canada, or elsewhere) with relatively large sample sizes (>40).  It’s still not perfect, since samples came from all across Newfoundland, so there could be subtle spatial differences that we couldn’t figure out, but it’s a heck of a lot better than what we knew before (which was, essentially, nothing).

    So while murres aren’t affected by plastics enough to cause problems (either to individual birds, or murre populations), other species aren’t so lucky.

    In Australia, about 95% of Flesh-footed Shearwater (Puffinus carneipes) chicks have plastic numbering tens to hundreds of pieces.  In many cases, it’s a likely cause of death for many chicks on Lord Howe Island in the Tasman Sea.

55.5 g of plastic/person on Qantas flight from
Sydney to Lord Howe Island. This adds up to about
2.1 metric tons/year. Photo by Alex Bond.
   Working on applied conservation can be challenging – not just because the work is hard, or the field sites remote, but because it’s easy to feel a sense of despair.  Humanity is not going to stop producing plastic.  And even if the last bit of plastic ever were made today, its legacy would be around for hundreds (and maybe thousands) of years. But I (and you) can do something.  We can use science to understand the effects of plastics on marine life, and to bring about better pollution control. 

     But one thing everyone can do is cut down on the new plastic we use - in everything from face wash with “microbeads” (plastic that goes down the drain) to packaging, and plastic bags to toys.

Photo by Donald Pirie-Hay.
Dr. Alex Bond has been studying the effects of pollution, climate change, and fisheries on marine birds since 2005, and has worked in Newfoundland, the Aleutian Islands of Alaska, and Australia. He is currently a Visiting Research Fellow at Environment Canada in Saskatoon, Saskatchewan, Canada. You can follow him on Twitter and visit his blog. The views in this post do not necessarily reflect those of his employer. 

Want to Learn More?

Bond, A.L., J.F. Provencher, R.D. Elliot, P.C. Ryan, S. Rowe, I.L. Jones, & G.J. Robertson S.I. Wilhelm (2013). Ingestion of plastic marine debris by Common and Thick-billed Murres in the northwestern Atlantic from 1985 to 2012 Marine Pollution Bulletin DOI: 10.1016/j.marpolbul.2013.10.005

Bond AL, & Lavers JL (2013). Effectiveness of emetics to study plastic ingestion by Leach's Storm-petrels (Oceanodroma leucorhoa). Marine pollution bulletin, 70 (1-2), 171-5 PMID: 23507234

Avery-Gomm S, O'Hara PD, Kleine L, Bowes V, Wilson LK, & Barry KL (2012). Northern fulmars as biological monitors of trends of plastic pollution in the eastern North Pacific. Marine pollution bulletin, 64 (9), 1776-81 PMID: 22738464

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