It's a tad depressing that some scientists are telling him he's doing it wrong, and should instead be doing something else, like working to prevent plastics from entering the oceans in the first place. That is a vastly harder problem because plastics enter the oceans through many paths, from falling off container ships to washing down rivers to being carried out by the winds or falling off pleasure craft (I myself used to have several spare bumpers for my boat, donated by what I like to think of as "The Society for Mariners Who Aren't Very Good at Tying Knots").

We don't have particularly good data on which paths account for how much: http://www.sea.edu/plastics/frequently_asked_questions

Easy solutions, like anti-dumping treaties, are already in place. A relatively cheap means of removing plastic may not be a bad next step.

Citizens willing to put time, effort and money into investigating practical engineering solutions to these problems should be encouraged, not dismissed. Particularly by people who are not themselves working on the alternative solutions they claim would be superior.