Just so you know: Canned sardines are kosher.
This judgment would appear to be definitive, based on DNA evidence. Genetic testing by a parasitologist at the American Museum of Natural History has confirmed that the recent discovery of small worms in canned sardines does not render them treyf, or unkosher. It may render them unappetizing, but that judgment is up to the consumer (more on that later).
Photo by Flickr user: Ian S2010