Ethics of Reef Keeping
One of the most troubling problems with marine, and especially marine reef, keeping, is the vast majority of fish, invertebrates, live rock and live sand are taken directly from the reefs of the world, which are already under intense pressure from pollution, commercial net fishing, climate change, and other human activity.
Freshwater keepers have it good, since at least 90 percent of the fish, plants and invertebrates available are commercially raised. Marine keepers, on the other hand, rely on the ocean's reefs for their livestock, with only a small percentage (under 20 percent) captive raised or farmed. This ethically bothers many keepers, myself included, considering the sad shape of the reefs of the world.
Hard (small polyp stoney) corals in the Caribbean have declined by over 80 percent, from roughly 50 percent prevalence to currently less than 10 percent, over the last 30 years. The sharpest decline occurred in the 1980's, but continues to this day. Research indicates agricultural run-off raised the nutrient levels in the formerly pristine waters, causing the near local extinction of the herbivorous sea urchin Diadema antillarum, enabling algae, which thrives in the nutrient-rich conditions, to smother corals. Whole reefs have been denuded of hard corals and are now covered with thick green algae, with nothing to eat it. Though the decline has slowed since the massive die-off of the 1980's, it continues to decimate corals, which will lead eventually to the extinction of coral species specific only to the region.
As I write this efforts are underway to propagate those corals in protected areas to preserve said species.
Live rock and sand mariculture is a nascent industry in Indonesia, where most of the rock and sand for our tanks comes from. The vast majority is taken directly from the reefs, with blasting used to break up the rock by unscrupulous collectors. Live rock and sand mariculture is far more developed in the waters of the Caribbean and the Atlantic coast of Florida. The plus with such rock and sand is they are teeming with life, including corals, small fish, and many other kinds of creatures only found in the region. The minus is maricultured live rock and sand is many times more expensive than dried out rock blasted from an Indonesian reef, because of the cost of development and the weight of the rock, which is far more dense than that from Indonesia.
A handful of marine fish are captive raised, simply because the vast majority of marine fish go through an extended larval period in the planktonic raft that floats near the top of the water, before metamorphoses from larvae to fish and settling into the reef. The larvae consume different foods at each stage of growth, meaning most marine fish are wild caught. Though in the past many reef fish were caught using Cyanide, that practice has been almost eliminated, as it's highly illegal. Locals now have a financial largesse using diving gear and hand nets to capture fish.
The movie 'Finding Nemo' drove the commercial breeding of clown fish (Pomacentridae family), and the methodology is such that all commonly available clown fish can be home bred, and a book is available if one wants to try their hand at breeding clown fish. The pelagic stage is a week with clown fish, and the larvae are large enough to take marine Rotifers, which are easily home cultured. The tang species in the movie, unfortunately, is still wild caught, as are all surgeon fish, because of their extended pelagic stages. It will take years, perhaps a decade or more, for science to determine which foods the larvae need at each stage of development before captive-raised examples become available.
Other marines fish now available captive raised include some gobies, blennies, all sea horses, the mouth-brooding cardinalfishes, some dwarf angelfish, and several dottybacks, with more species becoming available regularly once foods are determined for the larvae for each stage of development. Obviously, the fish with shorter pelagic stages are the ones most likely to become available captive raised. I have hopes that beauties like Moorish Idols (Zanclus cornutus) and other rare and beautiful marine fish will someday be captive-raised.
A growing number of captive-raised corals and other invertebrates are becoming more and more available both in shops and online. One of the great successes are the giant clams (Tridacninae family), which are farmed by the millions in Asia, primarily in Japan, which views the clams as a delicacy. Because of the sharp decline of giant clams taken from Japanese waters for human consumption, a methodology was developed to captive raise the clams. Though the method is still top secret, the benefit is that of the marine reef keeper, who can, in good conscience, keep giant clam species in their tank.
Corals, too, are available commercially farmed. Currently, the small polyp stoney (SPS) and large polyp stoney (LPS) corals are available, as fragments taken from a large 'mother' corals glued to a ceramic plug. As the corals are branched, it is easy to secure captive-raised SPS corals. Soft corals, particularly polyp corals like sea mats, are available captive raised in a dazzling variety of colors, and more large polyp stoney corals are available captive raised every day.
Ethically, stocking one's marine or marine tank with captive and commercially farmed livestock, live rock and sand is, at least to me, far more preferable than the alternative of that ripped from reefs already under great stress. Though the variety of captive-raised fish are small, corals, clams, live rock and sand are easily found captive produced. One can completely stock his or her tank these days with aqua and maricultured items.