Divers and Home Aquariums
... if you want to conserve reefs, why do you have that
aquarium?
from the April,
2004 issue of Undercurrent
“We who
dive along the Kona Coast have seen a drastic and definite reduction
in our tropical fish populations over the past few years, due in part,
at least, to the tropical fish collectors’ increasing numbers.”
So says Dick Dresie, aka “Dick the Diver,” who conducts
shore dives at Hawaii’s most popular sites. His concerns are being
echoed by divers and conservationists worldwide.
Rene Umberger of Octopus Reef says “the entire southern Maui coastline
has been impacted by fish collecting (and run off), including Ulua Beach,
Makena Landing, and 5 Graves.”
In Vanuatu in the South Pacific, reefs are over-exploited for the lucrative
trade. A spokesman for tourism companies, Peter Whitelaw, told ABC Net
News: “There are particular reefs that they’ve targeted
and a lot of them are the very reefs to which we take snorkelers and
divers.” At Hat Island, dive operators told the Manchester Guardian,
38,000 fish were taken within one month last year.
Near Bali’s Barat National Park, the Wildlife Conservation Society
has seen a considerable decline in aquarium species. Prompted by cyanide
fishing at Helen Reef in Palau and Komodo National Park in Indonesia,
The Nature Conservancy is working to prevent the long-term effects of
this practice. Collectors squirt cyanide into crevices where fish hide.
The poison stuns the fish, making them easier to catch. But large numbers
of the weakened fish die in transit, so far more fish are collected
than necessary, to allow for a “fatality margin.” The poisons
destroy reef ecosystems by killing nontarget animals including coral
and invertebrates. In the Philippines, 70 percent of ornamental reef
fish are caught with cyanide.
Most coral reefs are located in developing countries. While fish collecting
is a source of income for the people, the aquarium trade has been heavily
criticized for damaging techniques occasionally used to collect the
animals, overharvesting some species, and the high mortality from inadequate
handling and transport of sensitive living organisms. Improper collection
and shipping practices can introduce alien species, result in overharvesting,
and threaten the extinction of target species.
The roster of nations exporting marine ornamentals reads like a diver’s
wish list. Besides those already mentioned, divers in Florida, Australia,
the Caribbean, Tonga, the Solomon Islands, Fiji, the Maldives, the Marshall
Islands, Samoa, Micronesia, the Dominican Republic, Mexico, Sulawesi,
and Kenya all collect marine organisms for export. Many work the same
reefs that we travel thousands of miles to visit.
As we reported last July, tropical fish sales have soared since the
release of the Oscar-winning animated feature “Finding Nemo.”
Blithely ignoring the movie’s message, hobbyists are rushing to
set up saltwater aquariums stocked with beautiful fish, corals, and
invertebrates.
Americans Collect Half the Reef Fish Taken
More than 20 million tropical fish are sold for aquariums each year,
98 percent captured in the wild. The trade brings in $330 million a
year, according to a new report from the U.N. Environment Program entitled
From Ocean to Aquarium. As many as two million people worldwide keep
marine aquariums, 600,000 households in the United States alone. Americans
buy 50 percent of the marine fish captured and 80 percent of the stony
corals.
Of the 4,000 species of fish that live on coral reefs, 1,471 species
are traded worldwide. Damselfish make up almost half, with angelfish,
surgeonfish, wrasses, gobies, and butterfly fish accounting for another
25 to 30 percent. The most traded species are blue-green damselfish
and clown anemonefish (heeere’s Nemo!).
Many ornamental fish quickly belly up in captivity. Graeme Faulkner,
owner of Perth Aquarium Centre in Australia, points out that tropical
marine organisms require lots of special handling. “You need to
spend [hundreds of dollars] to set them up in the right environment,”
he says. That includes a sizable tank, special lighting, proper food
(live prey for some species), live substrate with plenty of hiding places,
and filtration.
Naive aquarists often buy fish that aren’t suited to home tanks.
The bluestreak cleaner wrasse and the spectacular mandarin fish, for
example, are commonly traded, though they do not acclimate well to aquarium
conditions. Foureye butterflyfish, harlequin filefish, and Hawaiian
cleaner wrasse are also popular despite their restrictive dietary requirements.
As a result of high mortality rates, more fish are collected than necessary
to meet market demand — further depleting wild populations.
At the other end of the spectrum, nurse sharks are popular with aquarists,
though they are highly predatory, often eating other organisms in the
same tank. If they live long enough, they’ll eventually outgrow
home aquariums. (Try flushing one of those down the toilet!)
How Collectors Destroy Reefs
Those who collect marine organisms in the wild tend to be small-scale
fishermen who work alone or in small groups, either self-employed or
working for a wholesaler/exporter. In Sri Lanka and the Maldives, collectors
use hand nets. In Australia, the Pacific region, and Florida, fishers
often use much larger barrier, drop, or fence nets. Branching corals,
which provide shelter to chromis and other small critters, are often
snapped off to extract fish hiding among them.
Although poisons like cyanide are illegal in most countries, the U.N.
report notes that “the high premium paid (often large bribes),
the ease with which a great number of fish can be caught in a short
time period, the often poor law enforcement capacities, and high levels
of corruption have allowed the use of poison to spread rapidly throughout
the Asia-Pacific region and have made the eradication of this illegal
and highly destructive fishing technique nearly impossible.”
For most species, juveniles are preferentially targeted due to their
distinctive coloration, ease of maintenance, and size ratio with respect
to tank size. However, should juveniles consistently be heavily harvested,
“adult populations will suffer as only a limited number of young
will grow to reach adult size and replenish the adult stock.”
Some species are endemic to certain waters (such as the scribbled angelfish
of Australia and Papua New Guinea). Others are naturally rare, occurring
only in restricted locations, or naturally lower numbers. Other species
may be abundant at different sites, but their distribution is limited
to specific habitats. Ironically, increased rarity creates higher prices.
Banggai cardinalfish are sought for their appearance and easy adaptation
to aquariums. But they are restricted to the reef and seagrass habitat
of the Banggai Islands off the east coast of central Sulawesi, Indonesia.
They have the lowest fecundity rate of their species and a low dispersal
rate of their eggs, and they’ve been proposed for listing as “critically
endangered.” Seahorses form faithful long-term pair bonds, mating
exclusively with one partner. If a collector separates a pair, the reproductive
cycle ends. Males of many coral reef fish species, such as mandarin
fish, are preferred due to their distinctive coloration. But, concludes
the report, “selectively harvesting males of particular populations
on a regular basis may lead to reproductive failure and ultimately population
collapse due to heavily biased sex ratios in remaining schools.”
Sometimes unwanted aquarium fish are released into local waters, taking
hold as alien species. Examples include Moorish idols, sailfin tangs,
bursa triggerfish, and racoon butterflyfish. Six lionfish were accidentally
released in Biscayne Bay, Florida, from a home aquarium during Hurricane
Andrew in 1992. Divers are now seeing lionfish as far north as the Carolinas.
Trade in Live Coral, Sponges, and Anemones
Besides fish, 140 species of stony coral and 60 different soft corals
are traded worldwide, perhaps as many as 12 million pieces a year. Some,
like carnation coral, lack the ability to create food through photosynthesis
and must filter particles and nutrients in the water column; in aquariums,
they usually die within a few weeks. According to the UNEP report, “significant
reductions in population densities of corals due to collection of colonies
for the aquarium trade could have implications on their reproductive
success and thus long-term reef stability and health.”
More than 500 species of invertebrates — sponges, molluscs, shrimps,
and anemones — are also traded as marine ornamentals. The annual
trade estimate is as high as 10 million animals. Collectors harvesting
corals and other immobile invertebrates often use hookahs and carry
hammers, iron crowbars, chisels, or screwdrivers to remove colonies.
The most popular invertebrates mainly feed on algae, parasites, or dead
tissue (e.g., cleaner shrimp) and dead animals (e.g., hermit crabs).
These species are particularly important in keeping other aquarium fish
healthy. However, removing them from their natural habitats reduces
diversity on harvested reefs, once their cleaning services are no longer
available.
Fiji is the world’s primary supplier of live rock (covered with
decorative coralline algae and other tiny invertebrates). Besides being
pretty, these organisms consume waste and produce oxygen, filtering
aquarium water. Each year, 800 tons are harvested from the edges of
Fiji’s reefs or within shallow lagoons — about 95 percent
destined for the U.S. Much harvested live rock, subsequently considered
unsuitable for export, is discarded and thrown back into the sea.
Large-scale removal of live rock, the result of hundreds of years of
accretion, can undermine the structure of coral reefs. Some harvesting
areas in Fiji have been converted into rubble and may never recover.
With help from the World Wide Fund for Nature, some Fijian villagers
have declared their traditional fishing grounds a taboo area, banning
extractions.
Many countries prohibit certain capture methods (such as cyanide in
Indonesia). Some set size limits for individual species and require
permits or licenses. Florida prohibits collection from certain sites
(marine reserves or other restricted areas like those in Hawaii). However,
rules and regulations vary from one country or political jurisdiction
to the next, as does enforcement.
Should a Conservation-Minded Diver Have a Home
Aquarium?
All this raises the question: Should scuba divers who have seen first
hand just how important it is to conserve reefs own aquariums at all?
Sure, they look cool, but we get to see these critters in their natural
habitats — which is even cooler. So why encourage someone to remove
them?
About the only proper way a diver can own a saltwater aquarium is to
stock it with species raised just for that. Eric Borneman, author of
Aquarium Corals: Selection, Husbandry, and Natural History, says, “be
aware of what wild collected species are common, and which are not,
and always purchase sustainably collected, maricultured, or aquacultured
stock.” Fish that are aquacultured (tank raised) or maricultured
(cultivated in their natural environment) can be purchased from most
reputable dealers and websites. However, merely two percent of the marine
aquarium fish traded are cultured — the rest come from the wild.
Only a few cultured species are available, primarily clownfish, dottybacks,
and gobies. As Borneman says, “they may cost you a bit more, but
these specimens will be selected and bred to thrive in captivity, so
you can expect them to enjoy longer and less stressful lives than wild
transplants.”
If, however, you still can justify keeping captured fish in your home,
then look for stores certified by The Marine Aquarium Council (MAC),
which develops standards for quality wild-caught products and sustainable
practices. Collectors, wholesalers, exporters, importers, and retailers
are evaluated and certified for compliance with these standards. Certified
retailers displaying MAC labels on their windows and tanks offer MAC-certified
marine ornamentals from certified suppliers. Only a handful of suppliers
and dealers are currently certified (see www.aquariumcouncil.org/
subpage.asp?page=130§ion=3).
You can download the report From Ocean to Aquarium by the U.N.
Environment Program at www.unep.org/PDF/From_Ocean_To_Aquarium_report.pdf.
— Larry Clinton
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