Observe Size and Weight Regulations
Hawaii institutes strict size and weight minimums on the fish you may keep. Animals that do not meet these guidelines must be released alive. For example, aholehole must measure at least 5 inches in length, while the minimum size for an opelu kala is 16 inches. Measure the fish by applying the tape measure to the snout of the animal and stretching it across its length to the middle of the tail.
Pay Attention to Seasons and Bag Limits of Marine Invertebrates
Depending on your fishing method, you might actually net some marine invertebrates in addition to the fish you were going for. Many of these invertebrates have actual seasons during which harvesting them is permissible, assuming that they meet the size or weight limitations. For example, spiny lobsters may be caught between September and April, as long as the carapace measures 3 1/4 inches in length. Moreover, only male Samoan crabs bigger than 6 inches across may be kept, while octopi must weigh at least 1 pound to be bagged.
Use Only Approved Gear
Because of the presence of protected marine life in Hawaiian ocean waters---among them are sea turtles and monk seals---there are several gear restrictions for those fishing in saltwater. The use of throw nets is limited to devices that have mesh sizes in excess of 2 inches. Nets must be checked every 2 hours and non-game fish must be released. Nets used for handling fish caught with a fishing rod are exempt from the 2-inch mesh requirement but may not be used for catching fish.
Apply for a Freshwater Fishing License
Anglers intending to bag bass, rainbow trout or channel catfish---or those planning on fishing in streams, Kauai's or Oahu's public fishing areas or Nuuanu Reservoir---must apply for a freshwater fishing license. Children may apply for a fishing license if they are between the ages of 9 and 15; children younger than 9 may fish without a license, as long as they are accompanied by a valid license holder. Keep in mind that the number of fish a child without a license bags does count against the daily limit for the adult in the party.
