Anchialine ponds exist in inland lava depressions near the ocean. They are fed by freshwater springs or from percolation from the water table. The water level rises and falls with the tide and salinity varies from fresh to saltier than sea water. Although the anchialine ponds do not have any direct connection to the ocean, somehow, the opae'ula colonized these ponds.
Most Hawaiian anchialine ponds are in the youngest lava areas of the Big Island of Hawaii and Maui. But not all anchialine ponds are natural. In 1965, on the island of Kahoolawe, the military detonated 500 tons of explosive in an area about 50 meters from the shoreline. The "Sailor's Hat" blast crater is about 50 meters in diameter and penetrated the water table to a depth of about 5 meters at maximum. The water level rises and falls with the tide and because there is no direct connection to the ocean, Sailor's Hat is considered an anchialine pond. A biological inventory in 1992 showed colonization by opae'ula.
In Waikoloa in South Kohala and on other parts of the Big Island, newly constructed brackish water ponds quickly are colonized by opae'ula. The creature has a relatively long lifespan, low reproduction capacity, and known to live in the underground water table. When excavations penetrate the water table, a pond naturally forms and opae'ula quickly appear.
There are several similar anchialine pond shrimps with opae'ula being the most numerous. They are the smallest and the only herbivore, feeding mainly on algae and bacteria. Other anchialine pond shrimp are predator carnivores feeding primarily on opae'ula. The most numerous of the others is the Red Alpheid Predator Shrimp (Metabetaeus lohena). Several of the others are relatively rare and may be known to exist only in a single anchialine pond.
Ponds where opae'ula still thrive are "off-limits" either because they are surrounded by rough lava and inaccessible or in official preservation areas. If this was privately owned, how long would it be before it was "improved" with exotic landscaping and colorful fish introduced into the ponds?
|Although far from the ocean, the ponds are natural low spots that fall below the water table. Brackish water shows tidal movements. The opae'ula can somehow travel underground through lava tubes or tiny cracks in the lava. But other larger shrimp or fish can not and opae'ula can thrive as long as there are no predators.|
Anchialine ponds represent a unique ecosystem that is disappearing on the Big Island as development of large resorts and access roads fill in the ponds. As the ponds become more accessible to the public, exotic ornamental fish such as guppies or mollies are introduced into the ponds. Colorful koi create beauty in resort or residential ponds. Food fish such as tilapia, aholehole, mullet, and trout are grown. Fishermen throw their leftover live bait shrimp into the ponds. These exotic fish and shrimp become dominant predators and the opae'ula retreat into the underground water table. Old-timers can recall when opae'ula were numerous in many anchialine ponds that were not large enough for fish aquaculture.
Colorful Japanese Koi are popular fish to grow in natural anchialine ponds in the hotel and resort areas. The beautiful natural lava formations provide a stunning pond bottom and the fish thrive. Such fish ponds are attractive and ideal for both businesses and residences where these ponds exist naturally. These are on the grounds of a hotel in Hilo's Banyan Drive.
|Hilo's famed Liliuokalani Gardens on Banyan Drive is one of the larger Japanese style gardens that was originally a series of anchialine ponds where opae'ula was once the only inhabitant.|
Some anchialine ponds are large and cover many acres. The ancient Hawaiians were
highly skilled aquaculturist who stocked the ponds with choice young fish. They fed
the fish daily at the same spot and at the same time so fish could easily be caught as
Today, the Nakagawa family of Hilo continue the tradition. They operated SEASIDE RESTAURANT, which is very popular with both locals and tourists.
|Reservations are recommended, and if you arrive early, stroll through the ponds and see various fish-raising activities. This pond is one to three feet deep and is used to grow aholehole and mullet. The mullet shown are about 18" long and weigh two to three pounds each.|
|A DYING ANCHIALINE POND. This pond in Hilo is nearing it's end. It was once a lava depression with no vegetation or fish and colonized with opae-ula. Now vegetation has developed and it's filled with Mexican Mollies. Bottom silt is thickening and soon there will be no water showing and it will become a soggy marsh, then grassland, and later a forest. To restore this pond, it will be necessary to remove all vegetation, silt, and alien fish. But even if restored, it will be a fragile situation and easily begin to move back into the evolutionary cycle.|
Even the most enthusiastic opae'ula lover must recognize that there are competing interests regarding anchialine ponds and there will be a long-term competition between development and preservation. Owners of private property have every right to utilize their property. Sometimes ponds are filled when roads are built. Other ponds are filled in to create building space. Each year we loose a few more ponds to commercial and residential development and it is now estimated that over 98% of the ponds are no longer in pristine condition! Those ponds that are not filled in become part of landscaped gardens, and once exotic fish are introduced, opae'ula disappear.
The larger ponds were natural fish ponds and ancient Hawaiians were highly skilled aquaculturists. They built stone walls to convert natural bays into fish ponds that had a system of gates and weirs to allow water to circulate and to allow small fish to enter. As the fish grew, they became too large to leave.
Smaller ponds were used to cultivate opae'ula that were used in several unique native Hawaiian fishing methods. Netted and mixed into a mud ball, the mud ball was wrapped in cloth with a weight attached to a long rope. When dropped on the opelu (mackeral) "koa" (a place where fish congregate and were fed, the mud ball fell free when it reached the end of the rope. The mud obscured the water and the opae-ula swam for the surface with the opelu chasing them to the surface. As the fish came to the surface, more "chum" was thrown and with patience and skill, a feeding frenzy was created. While the fish were distracted, others surrounded and netted the school. They also used lift nets or other techniques. The Hawaiians took what they needed and released the rest.
There is a very serious conflict between the old Hawaiian sustainable culture and the aggressive opportunistic harvesting of natural resources. Hawaii is struggling to resolve these competing interests. The same conflict affects the future of opae'ula. There are now quiet efforts to restore the koas and develop larger sources of opae'ula to be used to demonstrate traditional Hawaiian fishing methods as part of educational programs. This presents a major challenge!
PRESERVING AND RESTORING THE ANCHIALINE PONDS
In the 1960's before the Queen Kaahumanu Highway connected Kawaihae and Kailua-Kona, most of the anchialine ponds in South Kohala were in pristine condition and filled will opae'ula. The acknowledged anchialine pond authority is Dr. Richard Brock who has done most of the surveys. Last year, he estimated that 95% of the ponds could no longer support opae'ula as they were converted to fish ponds, filled in, or filled with alien predator fish. In the past year, more ponds were invaded and Dr. Brock now estimates that 98% of the ponds are lost. The ponds are very fragile!
This pond is filled with tilapia with typical tilapia nesting holes. Tilapia are mouth brooders and will hold the young in their mouths. If a seabird catches one and is frightened and drops it into another pond, it effectively can start a new colony in a previously pristine pond. In Kauai, aquaculture shrimp ponds were once free of fish. But over time, birds introduced tilapia which greatly reduced shrimp production and possibly introduced diseases. In addition to removing the fish, it is also necessary to remove the accumulated pond silt.
Without intervention and preservation, the opae'ula will disappear. Some enlightened property owners and developers have made sensitive and commendable efforts to preserve and enhance Hawaiian cultural traditions. The legendary Kenneth Brown restored the ponds at Mauna Lani Resort and the dredging of the silt took over a year. More recently, outstanding work has been done at Hualalai and Kukio on the Big Island of Hawaii. Kohanaiki is embarking on development with a major commitment to preserve the ponds. Other Big Island resorts have also made commendable efforts, but more must be done and we'll be sharing the stories of these successes in the future.
Opae-ula is already very heavily regulated. But because the agencies lack funds for enforcement, regulations are often largely ignored. While individuals can catch opae'ula for their own use, it is illegal to sell without a commercial fishing license including a daily report of their catch and the names of their purchasers. It is also illegal to collect coral, sand, and "live rock" for sale. Any retailer selling bacteria inoculated live rock opae'ula units must be licensed. Fuku-Bonsai meets all requirements and we are an aquaculture facility licensed by the Aquatic Division of the Hawaii State Department of Land and Natural Resources. Our Hawaii retailers are licensed to sell our products. In addition, Fuku-Bonsai has been cleared by Animal and Plant Health Inspection Service (USDA-APHIS) to use inspected high-velocity pumice ejecta under the only Limited Media Permit created specifically to allow use of the material in export products.
Opae'ula are destined to become much more well known and in demand as more people learn about them. Fuku-Bonsai's captive breeding program is a step in an appropriate direction and we have begun research to create a mass cultural system. A public exhibit has been created at the Waikiki Aquarium in Honolulu. We will develop Micro-Lobster educational programs, offer breeder tanks, and serve as a resource. This will help assure the future of the species which currently depends upon anchialine ponds.
CREATING NEW ANCHIALINE PONDS & MASS CULTURE SYSTEMS
Restoring existing anchialine ponds is a daunting challenge. Rotenone has been cleared for removal of alien predator fish only by certified applicators and only in some circumstances. Removing the bottom silt requires a huge amount of equipment and labor. Sometimes, even after the opae'ula return, the alien predator fish also return. Any traces of silt turns into soft algae scum that smothers the openings. Not all restoration efforts are successful!
An alternative is creating new ponds that are not directly connected to compromised ponds. Several such ponds have been created and these are being studied to see if they provide a long-term solution. There is significant concern that these ponds are very vulnerable to fish invasion and many prefer that these ponds remain unmarked.
The major other alternative is to create mass culture systems and this may be the ideal solution. Such a facility can be screened and secured to prevent the introduction of predators. It will allow creating ideal environments that will sustain large populations. Recent advances in reproduction research shows promise!
*** Continue to ANCHIALINE PONDS (PART II)