Threats to the Marine Environment

Many cultures have treated bodies of water as convenient repositories for trash, "bottomless" sources of food and natural resources, or something to be dredged, filled, or drained when deemed necessary. Although we know better in these environmentally-aware times, misuse continues around the world, while areas with improving attitudes and practices will remain scarred for years to come. Here are a few examples human-induced impacts upon coral reefs observed around the Pacific.

Trash dumped in our oceans & beaches

Floating Debris, Hanauma Bay, Oahu	Plastics, Kaloko, Oahu
Plastics & Glass, Midway Atoll, NWHI	Plastics & Glass, Midway Atoll, NWHI
Discarded Metal, Faga'alu, American Samoa	Burnt Trash, Kaena Point, Oahu
Shopping Bag, Pago Pago, American Samoa	Shopping Bag, Pago Pago, American Samoa
Shopping Bag, Pago Pago, American Samoa	Shopping Bag, Pago Pago, American Samoa
Beer Cans, Pago Pago, American Samoa	Diaper on Coral, Faga'alu, American Samoa
Diamond Head, Oahu	Diamond Head, Oahu

Marine debris, mainly plastic, accumulates as drift lines in the open ocean, bays and harbors, and beaches. This is a common sight in Hanauma Bay at the 'Witches' Brew', where winds and waves accumulate trash against the sea cliffs.

The beaches and reefs of the Northwest Hawaiian Islands receive the lion's share of marine debris due to prevailing winds and currents in the North Pacific. Employees of various government agencies and volunteers remove hundreds of tons of discarded fishing gear (nets, rope and fishing line) from coral reefs, in addition to every conceivable type of trash off these formerly pristine islands inhabited by the endangered Hawaiian Monk Seal and Green Sea Turtle.

The pre-industrialized world disposed of trash easily since natural products were biodegradable. The rapid spread of a westernized lifestyle to traditional cultures has many drawbacks including waste-disposal. For example, banana leaves and gourds used with meals were easily discarded. The plastic and aluminum replacements are still discarded in the same manner.

Fishing line wrapped around coral

Monofilament on Coral, Blowhole, Oahu	Polypropylene line on coral, Hanauma Bay, Oahu
Monofilament on Coral, Blowhole, Oahu	Monofilament on Coral, Blowhole, Oahu
Line-choked dead coral, Portlock, Oahu	Line-choked dead coral, Portlock, Oahu
Removing Fishing Line, Portlock, Oahu	Removing Fishing Line, Portlock, Oahu
Removing Fishing Line, Portlock, Oahu

Unfortunately fishermen are some of the worst offenders when it comes to littering. Trash is left along roadsides and fishing sites or dumped in the ocean. Lost tackle wraps around corals, killing them. Tangled masses of monofilament line ensnares animals for years to come.

Marine Life Entrapment & Death in Abandoned Fishing Gear

Green Sea Turtle drowned after being hooked & snagged on the reef. Koko Head, Oahu, Hawaii, 7/11/2008

This triggerfish was hooked by a fisher and the line broke after becoming entangled in the reef. It was unhooked and released. Portlock, Oahu, 20 feet

Marine Life Killed & Discarded by Fishers

Dead Eel, Portlock, Oahu

Marine animals are killed by fishers for use as bait or caught and left to die on dry land.

A fisher just stood on these corals at Faga'alu, American Samoa


A scuba diver kicked this Lobe Coral, Kewalo, Oahu

Corals are trampled or smashed by careless fishermen, reef-walkers, snorkelers, and scuba divers, or ripped apart by anchors.

Coral Diseases

Bleaching, Pokai Bay, Oahu	Bleaching, Kaneohe Bay, Oahu
Trematode infection, Kewalo, Oahu	Trematode infection, Kewalo, Oahu
Trematode infection & subsequent algal growth Kewalo, Oahu

Coral diseases, especially bleaching, is occurring throughout the warm oceans, laying waste to once-beautiful reefs. As global temperatures increase so will our corals suffer. Trematode infections may be triggered by damage caused by contact with diver's fins.

Coral killed by sediment

Faga'alu, American Samoa

Corals are also sensitive to choking by mud and sand washed into the ocean from mismanaged land-clearing, agricultural, and construction sites. Dredging and filling has the same effect.

Coral damaged by storms

Faga'alu, American Samoa

Corals must also cope with large waves caused by storms. Disturbed substrate may be colonized by toxic dinoflagellates that have been known to cause Ciguatera fish poisoning and other diseases. Dead corals eventually break apart, forming coral rubble, or become incorporated into the reef structure by coralline algae.

Bioerosion

Dead Porites coral with bore-holes, Kewalo	Sea Urchin bore-holes, Makapu'u, Oahu
Midway Lagoon with Pencil Urchins

Natural breakdown of reefs takes place continuously. Parrotfishes bite off chunks of coralline material while some large filefishes remove the tips of Cauliflower coral. Boring sea urchins, sponges, and mollusks erode reefs from the inside-out. This process is easily observed in Midway Lagoon where the ancient reef limestone is riddled with urchin holes, causing sections to break apart during high surf.

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