10 Threats to Ocean Life

陳橙

The ocean is a beautiful， majestic① place that is home to hundreds of thousands of species. These species have a dizzying array of variety and come in all shapes， sizes and colors.? There are thousands of known species， but there are also many more still to be discovered as the ocean is largely unexplored.

Despite knowing relatively little about the ocean and its inhabitants， weve managed to screw it up quite a bit with human activities. Reading about different marine species， you often read about their population status or threats to the species. In this list of threats， the same ones appear over and over. The issues may seem depressing， but theres hope—there are many things each of us can do to help.

The threats are not presented here in any particular order， as they are more urgent in some regions than others， and some species face multiple threats.

Ocean Acidification②

A good metaphor for ocean acidification， developed for the National Network for Ocean and Climate Change Interpretation （NNOCCI）， is osteoporosis③ of the sea.? Absorption of CO2 by the ocean is causing a lowering of the oceans pH， which means that the oceans chemistry is changing.

Climate Change

Here Ill use another metaphor from NNOCCI， and this one also relates to fossil fuels. When we burn fossil fuels like oil， coal and natural gas， we pump CO2 into the atmosphere. The buildup of CO2 creates a heat-trapping blanket effect， which traps heat around the world. This can result in temperature changes， an increase in violent weather and other threats were familiar with such as melting polar ice and rising sea levels.

Overfishing

Simply put， overfishing is when we harvest too many fish. Overfishing is a problem largely because we like to eat seafood. Wanting to eat isnt a bad thing， of course， but we cant always harvest species exhaustively in an area and expect them to continue to survive. The FAO estimated that over 75% of the worlds fish species are either fully exploited or depleted.

In New England where I live， most people are familiar with the cod fishing industry. Eventually， in the cod fishery and other industries， larger and larger boats were fishing in the region， which resulted in a population collapse. While cod fishing still occurs， cod populations have never returned to their former abundance. Today， fishermen still catch cod but under tight regulations that try to increase the population.

In many areas， overfishing occurs for seafood. In some cases， it is because animals are caught for use in medicines （e.g.， seahorses for Asian medicines）， for souvenirs （again， seahorses） or use in aquariums.

Poaching and Illegal Trade

Poaching is the illegal taking? （killing or collection） of a species.

Bycatch and Entanglement

Animals dont live in separate groups in the ocean. Visit any ocean region and youre likely to find a large number of different species， all occupying their various habitats. Because of the complexity of species distribution， it can be difficult for fisherman to catch just the species they intend to catch.

Bycatch is when a non-targeted species is caught by fishing gear （e.g.， a porpoise is caught in a gillnet or a cod is caught in a lobster trap）.

Entanglement is a similar issue and occurs when an animal becomes tangled in either active or lost （“ghost”） fishing gear.

Marine Debris④ and Pollution

Marine debris is a man-made material in the marine environment that doesnt naturally occur there.? Pollution can include marine debris， but also other things such as oil from an oil spill or runoff of chemicals （e.g.， pesticides） from land into the ocean.

Habitat Loss and Coastal Development

As world population increases， more of the coastline is developed and our impacts on areas such as wetlands， seagrass meadows， mangrove swamps， beaches， rocky shores and coral reefs increase through development， commercial activities and tourism.? Loss of habitat can mean species have no place to live —with some species that have a small range， this can result in a drastic decrease or extinction of populations. Some species may need to relocate.

Species may also lose food and shelter if their habitat size decreases. Increased coastal development may also affect the health of the habitat itself and adjacent⑤ waters through an increase of nutrients or pollutants into the region and its waterways through construction activities， storm drains， and runoff from lawns and farms.

Habitat loss may also occur offshore through the development of energy activities （e.g.， oil drills， wind farms， sand and gravel extraction）.

Invasive Species

Native species are those that naturally inhabit an area.? Invasive species are those who move into or are introduced into an area in which they are not native. These species can cause harm to other species and habitats. They may have population explosions because natural predators dont exist in their new environment.

Shipping Traffic

The most tangible⑥ problem caused by shipping is ship strikes—when whales or other marine mammals are hit by a ship. This can cause both external wounds and internal damage， and can be fatal.

Other issues include noise created by the ship， release of chemicals， transfer of invasive species through ballast water and air pollution from the ships engines.? They can also cause marine debris through dropping or dragging anchors through fishing gear.

Ocean Noise

Human-made noise in the ocean includes noise from ships （propeller noise and noise from the mechanics of the ship）， noise from seismic airgun noise from oil and gas surveys that emit regular blasts of noise over long periods of time， and sonar from military ships and other vessels.

注：① majestic 壯觀的

② acidification 酸化

③ osteoporosis 骨質疏松

④ debris 碎片

⑤ adjacent 鄰近的

⑥ tangible 有形的