From The Honolulu Advertiser:
Health experts are not sure what is causing Mantis Shrimp found in the muck of the Ala Wai Canal to grow larger than their normal size, but one thing is clear, they say: You shouldn’t eat anything out of the canal.
State Department of Health signs posted along the canal warn people not to eat fish or shellfish found in the Ala Wai because of possible contamination from urban runoff into the Waikiki waterway. But that didn’t stop Keith Harvey, a barge mate working on the Ala Wai dredging project. Harvey cooked one of several Mantis Shrimp (Odontodactylus Scyllarus) pulled from the mud at the bottom of the canal. The largest shrimp weighed in at 1.35 pounds and 15 inches.