As a dive school, our top priority always seems to be to get people into the water and bring them back happy and safe. But, as a reef ecologist, and really just as any aquatic life enthusiast, there’s also a greater responsibility we don’t always think about. We need to protect the ecosystems that support not only the dive industry, but all maritime industries, and of course, an incredible amount of fish, invertebrate, plant, and microbial life.
As divers and snorkelers, we can damage reefs in any number of ways. We could accidentally touch the coral, stressing it out with our skin oils, or kick it and break a piece off with our fins. Our trash could make its way onto the coral colonies, smothering and killing the whole colony. We could use chemicals (ie. sunscreens) that leak into the water and stress already stressed corals. We could place a camera on a sponge to help steady that one great photo, or grab onto the reef to steady ourselves. We could do innumerable things to smash or otherwise kill the reef we’re so drawn to. But there’s another way we impact the reef, and it kills the reef significantly more than anything mentioned above.
Anchors are used to keep boats in place. Seems innocent enough. That makes it easy to keep divers in one place. But with any kind of wind, wave, or current action, the boat will pull on the anchor and anchor chain which can do irreparable damage to reefs, sea grass, and any benthic substrate. Even if an anchor is placed away from coral, the bouncing and pulling action of the boat on the anchor chain can rip, smash, or overturn coral in its wake. Either can take out in minutes a coral that has taken 20+ years to grow. They also smash the tips off of coral colonies, leaving white circles of skeleton exposed. More often than not, this ends up killing the coral fragments.
While it might not seem like a huge loss for one coral colony to be crushed or dredged out, commonly used dive sites can see several boat anchors an hour during high seasons. If even only 5% of the reef is damaged by these anchors, and the reef manages to grow at an average of 5% a year, the anchor damage is already negating any growth of the ecosystem. But usually anchors do far more than 5% damage. It isn’t unusual to find more than 20% damage along coral reefs from anchors and anchor chains. This also affects areas surrounding the reefs; in high tourist seasons, anchors have been reportedly destroyed over 70% of seagrass beds.
This is why the installation of mooring buoys is so important. Mooring buoys are permanent structures rooted into the sediment to which boats can tie up, eliminating the need to anchor each time they visit a popular site. Mooring buoys can be tricky to implement though. They require the cooperation of local and sometimes federal governments, fishing communities, and commercial stakeholders which can be complicated. Communities are sometimes hesitant to install mooring buoys out of fear that fishermen will have easy access to the very fish the mooring is trying to protect. Inversely, the fishermen themselves are against the idea because it would interfere with their nets. Additionally, the buoys are often stolen for a variety of reasons.
Though, the effect can be a difference of life vs death. Mooring up can eliminate anchor damage to sensitive bottoms. But, if that isn’t an option where you dive, consider carefully placing the anchor by hand, using a sand anchor and swimming to the site, and using good anchor etiquette. Use only as much chain as you need to hold the vessel safely, motor towards the anchor to lift it vertically through the water column, and keep watch to make sure it isn’t dragging.
Wonderful dive sites will only stay wonderful for as long as we care for them. Negligence in any regard can quickly and irreversibly destroy entire underwater communities. Some days it feels like we have little say in what is happening to the environment, but there are aspects that we have direct control over. Reduction of anchor damage is possible and would make a much bigger difference than you may initially believe.
‘Anchor Damage’ was written by Roya
Photo Credit: COREsea.com
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