Nu‘uanu Freshwater Fish Refuge
(Nu‘uanu Reservoir No. 4), O‘ahu

The Nu‘uanu Freshwater Fish Refuge includes the City and County of Honolulu's Nu‘uanu Reservoir No. 4, located between Honolulu and Kailua off the Pali Highway. The reservoir is stocked with channel catfish, and is open to weekend public fishing three times a year, beginning in May, August, and November.

A Freshwater Game Fishing License and Entry Fishing Card are required. Prospective anglers must submit an application to the Division of Aquatic Resources several weeks in advance of an opening, and a lottery is then held to determine fishing times. All applicants are accomodated. The bag limit for channel catfish is two per licensee, and any channel catfish 16 inches or larger must be kept.

Next Opening, Fishing Applications

The next opening is scheduled for December 1, 2007. Applications are available October 21, 2007, and deadline for submission is November 9. Click on the link to download a PDF file (300 KB) of the application instructions.

You can buy a Freshwater Game Fishing License at various license agents on O‘ahu, or online at https://www.ehawaiigov.org/dlnr/fish/exe/fresh_main_page.cgi

Fishing

Record channel catfish caught in Nu‘uanu Reservoir #4: 27 lb 8 oz, 32", June 2, 1984

Recent openings

Channel Catfish

Channel catfish (Ictalurus punctatus) are omnivores that generally feed near the bottom on small fish, crustaceans, clams, and snails. They feed by day or night, and will eat a variety of plant and animal material. Originally found in the Gulf States and Mississippi Valley from Mexico to Canada, channel catfish were eventually introduced throughout the United States. They were brought to Hawai‘i in 1920.

Most channel catfish are under 10 pounds, but have unofficially exceeded 50 pounds in Hawai‘i. The state record fish of 43 pounds 13 ounces was taken from Lake Wilson in central O‘ahu. The North American record fish was 58 pounds, landed in South Carolina.

Channel catfish are recognized by their deeply forked tails, and most have dark spots scattered along their sides. Older males become dark in color and lose their spots.

Caution should be used when handling channel catfish, because they have sharp spines at the forward edges of their dorsal and pectoral fins, which can inflict injury. The barbels ("whiskers") are harmless; they function as sensory receptors.

Spawning occurs during the late spring, generally May and June in Nu‘uanu. Females spawn once a year, and are estimated to produce 1,000 to 3,000 eggs per pound of body weight. During the spawning season, a male will select and prepare a nest site, then guard it against all intruders until his fry leave. The female is attracted to the nest, where she lays eggs in a gelatinous mass on the bottom. The male then cares for the eggs, fanning them with his fins to provide oxygen and remove wastes. Eggs hatch in 10 to 12 days, depending on water temperature. The newly-hatched fry have large yolk sacs, which provide nourishment until the fish are more fully developed. The yolk sacs are slowly absorbed over the next five days, at which time fry begin feeding on their own. Channel catfish reach sexual maturity at three to five years, and are believed to have a lifespan of up to 25 years or longer.

DAR biologists and technicians take an active role in maximizing survival from spawns in Nu‘uanu Reservoir No. 4. Predatory fishes found within the reservoir, such as cichlids, prey on eggs and fry. During the spawning season, DAR staff locate nest sites along the dam wall, remove egg masses, and transport them to a hatchery facility at Sand Island. The catfish are raised to fingerling size, then taken back to Nu‘uanu and reared in floating cages. They are released into the reservoir once they reach about 16 inches.

History

There are four open reservoirs in Nu‘uanu along Pali Highway, numbered 1 through 4 (see photo above). They were built during the period from 1890 to 1910, and their original purposes included hydropower, flood control, and domestic water. The hydropower and domestic water uses were soon replaced by other sources, and only the flood control purpose remained.

In constructing the largest reservoir, No. 4, a tower was built near the dam to control water level with a valve. When water is at the tower's 35 ft level, the reservoir's surface area is about 25 acres. At the 25 ft level, the area is about 10 acres.

Shortly after World War II, the Territorial government began introducing freshwater game fishes in waters throughout the islands. The reservoir system in Nu‘uanu was utilized as a refuge and research site for introduced sportfish. The first opening for channel catfish fishing was July 5-6, 1969, when 96 anglers caught 339 catfish.