The fact that J Neil Young (Letters, April 10) cannot find sources for the "thousands" of marine birds and mammals that die annually from plastic ingestion reflects more on his inability to surf the internet properly than the reality of the situation. Plastic bags and nylon rope are not the only pollutants in the sea.

The facts are that not thousands but hundreds of thousands, if not millions, of seabirds, marine mammals and reptiles the world over die from plastic ingestion and contamination from oceanic pollution. Even the most remote areas of Antarctica and the creatures that live there are now internally contaminated.

I commented first on plastics ingested by seabirds in 1985 in British Birds (Vol 78). Seabirds such as fulmars, storm petrels and shearwaters in particular ingest these floating particles in mistake for food.

The polyethylene resin "beads" they swallow are the feedstock of the plastics industry and are the most insidious, getting into the sea via factory (cracker-plant) outfalls and the bursting of bags on wharfsides when being exported and imported.

Scotland, along with Japan, is among the worst of these culprits, and 98% of Scottish fulmars examined, from a population of more than one million birds, contain plastic marine debris that was directly or indirectly the cause of their demise.

The plastics factories appear to get off scot-free from prosecution, despite having polluted almost every Scottish beach and beyond.

It is one very good reason why legislation on marine nature reserves is long overdue. Perhaps then the polluters will be called to account. Sadly, no political party has taken up the cause.

Mr Young should look up work by Dutch ornithologist Jan van Franeker or check New Scientist 2005 titles such as "Seabirds ingest bellyfuls of plastic pollution" and publications such as those by the Marine Conservation Society, the Marine Pollution Bulletin or Marine Ornithology.

The RSPCA barely knows the problem exists. Mr Young and other readers can also go directly to the US Environmental Protection Agency website for further reference data: www.mindfully.org/Plastic/Ocean/ Plastic-Aquatic-EPA842B92010-Dec92_7.htm or www.epa.gov/owow/oceans/debris/ plasticpellets/index.html.

There is a plethora of publication on the subject covering 30 years.
Dr Bernard Zonfrillo, Ornithology Unit, Division of Environmental & Evolutionary Biology, Glasgow University.