Often, people take action only after it's too late.

Under the leadership of Peter Young, the state Department of Land and Natural Resources is pursuing an initiative that will dramatically improve the quality of our ocean environment — banning the use of lay gill nets in many areas of the state — before it's too late.

No single action will do more to restore precious nearshore aquatic resources.

This month, the department is conducting a series of informational meetings on rules to ban lay nets on Maui, in much of Kane'ohe Bay, and off Kailua, Lanikai and the entire coast from Koko Head to the Reef Runway.

The use of lay nets in other areas around the state would be significantly restricted.

The proposed rules would not further restrict the use of throw nets, opelu or akule nets, or aquarium nets; nor would it apply to lobster traps or fish traps.

It's expected that a few of those who currently use gill nets will strongly oppose the measure.

They will argue that it is a traditional method of fishing in Hawai'i, and that factors such as habitat destruction and pollution, and hook-and-line fishermen, are more important causes of the degradation of nearshore resources. Many will probably point fingers at "irresponsible" net fishermen.

Finally, they will argue that lay nets are necessary for them to put food on the table.

These and other issues might be best discussed in response to a series of questions.

First, what are lay nets, or gill nets?

Lay nets are made of the same material as modern monofilament fishing line. This material is fabricated by machine into a mesh with "eyes" or holes in the net usually less than 3 inches across when stretched. The nets are suspended by floats while being held to the bottom with lead weights.

The nets are laid along reef or in sandy areas. Since the nets are practically invisible underwater, fish unwittingly swim into them. Their gills are hooked by the net and they become entangled.

Thus, the term "gill net" is also used to describe them. Lay nets are "blind" to the species or number of fish they trap. They indiscriminately catch nearly everything that swims in their path, including turtles and other protected species.

They should not be confused with the natural-fiber hukilau nets that Hawaiians have used for centuries. Hawaiians also herd fish into nets in a method called pa'i-pa'i fishing. None of them simply lay nets in the water and wait — often overnight — for fish and other creatures to become entangled.

The use of lay gill nets was never a traditional Hawaiian method of fishing. Japanese fishermen introduced them to Hawai'i in the 1940s and 1950s. Since then, their use has steadily increased because they are very efficient in catching everything that tries to swim past.

Has the number of nearshore fishes declined in Hawai'i?

Unfortunately, there is little historical data on the condition of our reefs or nearshore fishery resources. Techniques for counting fish such as those used today by marine biologists were unheard of 50 years ago.

However, there is considerable evidence that there used to be far more fishes in Hawaiian waters.

Virtually all commercially important nearshore species of fish have been declining over the past 50 years. Little reliable data exist before 1950.

It is no coincidence that the decline begins at the same time monofilament gill nets were introduced to Hawai'i.

Are factors other than fishing pressure important in the decline of nearshore fishes?

Historically, pollution and habitat destruction have unquestionably had some impact on fish populations. These factors are less important today.

The dredging of harbors and channels and the filling in of wetlands over the past century has had the most significant impact on habitat. In some cases, the dredging of harbors actually created new habitat.

Whatever impact these activities had in the past, it cannot now be reversed.

Pollution of our nearshore waters from sedimentation, sewage discharges, pesticides and other chemicals in runoff also has undoubtedly affected coastal water quality. Polluted runoff in streams and from storm drains may also affect water quality, particularly in bays and other areas where circulation is poor. However, the impact is negligible in areas with good circulation and water exchange.

Even the Ala Wai Canal has abundant populations of papio, o'io and other species.

The most important factor in the decline of our nearshore species is overfishing. This is the consensus opinion of virtually all the marine scientists who have studied the issue.

And contributing substantially to overfishing is the use of lay nets. There is little skill involved in using these nets, just the knowledge of where and how to set them to catch the most fish.

More important, however, is the manner in which lay nets work — they are virtual "curtains of death." Entire schools of fish are often caught in a single pass.

What hard evidence is there to show gill nets are to blame?

The Waikiki-Diamond Head shoreline fisheries management area is one of the few areas where data on fish populations have been correlated with fishing activities. This area has been rotated through different management regimes since 1978.

Data collected by marine resources scientists during these management regimes show that hook-and-line fishing had little effect compared to other fishing methods (spear, trap, net, etc.). In fact, the only times the fish population dropped significantly was when nets and spears were allowed.

Anecdotal information from fishermen remains one of the best sources of information regarding changes in the abundance of fish and the impact various methods of fishing have had on the resource.

Today, in most areas, even the lay-net fishermen are not catching many fish. There are simply few fish left to catch in most of our nearshore waters.

What are the long-term impacts of using lay nets?

Once the population of a particular species of fish drops below a critical level, ecosystem changes occur. And once significant ecosystem changes occur, the damage is long-lasting or permanent, and the fishes never come back.

What is being done about the problem in Hawai'i?

The Department of Land and Natural Resources has been working on improving the management of lay nets by regulating the size and use of nets for some time. In 1997, a new type of net appeared along the Wai'anae Coast that prompted renewed concerns.

This was a huge monofilament net that could be set on the bottom in depths 200 feet or more via a hydraulically operated drum on the bow of a boat. Such nets have the potential to devastate the fisheries in this and other areas of the state.

What are other states doing?

Florida experienced a major problem in the 1980s and 1990s when the price of mullet roe was high; foreign fisherman employed nets to catch these fish, killing off most other species in the process.

Consequently, in Florida, lay gill nets were banned in 1995. Since then, marine-resource specialists report a dramatic increase in the number of fishes. California, Oregon and Washington state all have bans or severe restrictions on the use of gill nets.

Please let your voice be heard. If we do nothing, soon there will be no fish left to catch or enjoy in Hawai'i.

Bruce S. Anderson is president of the Oceanic Institute. He wrote this commentary for The Advertiser.