Hawaiian Marine Life Profiles: Fish
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Found in Exhibit:
Shallow Reef, Open Ocean
|The wide variety of fresh fish that we see in our grocery stores and on the menus of our favorite restaurants is a delight for island residents and visitors alike. For those of us who eat fish, opakapaka, onaga and ehu are some of the more tantalizing names that lure in our taste buds time and time again. As consumers, many of us favor the snapper family because of their delicate, mild flavor and relatively firm meat. While we see them frequently on our dinner plates, how much do we really know about their appearance when they are alive? Where do they live? How big do they get? How does their commercial significance affect the sustainability of their species? A unique collaboration between the deep sea research group, Hawaii Undersea Research Laboratory (HURL), and the State Department of Natural Resources (DLNR) is providing us with some of the answers to these questions. Having a better understanding of this widely popular fish family may help us all to be more responsible in the future.
Opakapaka, onaga and ehu are all part of the snapper family, biologically characterized by their medium to large oblong body shapes, large heads, a flat area about their snout and brightly colored bodies ranging from red to yellows. According to the DLNR, onaga mature when they are approximately 26 inches long, or 4 years old. Onaga apparently must reach a large size before they spawn for the first time. Ehu mature at about 11 inches in length, when they are nearly 3 years old.
Snappers are also known as bottomfish, living in deep water habitats ranging from hundreds to more than a thousand feet below the ocean's surface. It is an entirely different and uniquely Hawaiian marine habitat: the deep volcanic slope. It is home to strange and familiar sea creatures alike, some of which have never been seen by humans until research submersibles captured them on film or scientists collected them for better understanding.
Creatures of the deep, such as snappers, must be able to thrive in reduced light or in perpetual darkness, crushing pressures and bone-chilling temperatures. Deep water fisheries, such as those for eteline snappers, are an important seafood market in the Hawaiian Islands, making up nearly 4% of all fisheries in Hawaii, and providing more than $2 million dollars in ex-vessel (off the boat) income. Currently the U.S. Department of Commerce lists both ehu and onaga as over fished species.
Researchers with the Hawaii Undersea Research Laboratory (HURL) and the State Department of Land and Natural Resources Department of Aquatic Resources (DLNR/DAR) are concerned about the status of these fishes and are exploring their habitat using research submersibles, such as the Pisces fleet and high-resolution multibeam sonar data and the Arcview geographic information system. Since these fish populations are currently declining, they hope to gain a better understanding of the geology and ecology of their habitats to ensure their sustainability.
Even though this work is still in progress, researchers believe they have already identified a number of important features of essential bottomfish habitat. Onaga and ehu were observed in areas characterized by a hard carbonate, basalt, or mudstone substrate. On walls and pinnacles with sharp slopes, fish were observed only in areas of exposed rock. By comparing these submarine observations with those of areas set aside for special management, resource agencies will be better able to confirm that they have made appropriate choices for the areas already designated based on recommendations from fishers.
Some of our important bottomfish populations are declining throughout the state of Hawaii. While there is much yet to be learned, organizations like Hawaii Institute of Marine Biology are trying to support the researchers and managers by growing these fish in captivity, and facilities such as Maui Ocean Center are offering the public the opportunity to learn more about them. Together with the Hawaii Undersea Research Lab, and the DLNR, these groups are working to gather important information and translate it into messages that are clear for us all to understand. The more we know, the wiser choices we will all make and the more we will be able to do to protect the sustainability of our island fish for the future. Fresh fish may be on our dinner menus tonight but what will we eat tomorrow?