With a horse’s head, the snout of an aardvark, a chameleon’s color changing abilities and independently operating eyes, a monkey-like prehensile tail, and—in males, not females—a marsupial’s pouch for the gestation of young, the mythical seahorse is one of nature’s most unique animals.
Increasingly, the characteristics that make seahorses so seemingly exotic, along with their alleged curative powers, have led to their demise—trade in seahorses is a leading cause of population declines of at least 50 percent globally and more than 90 percent in specific populations over recent decades. Given their small population sizes, low densities, preference for specific habitat types, low mobility, elaborate reproductive behaviors, high rates of juvenile mortality, and extensive prenatal care, seahorses are slow to recover from such exploitation.
Seahorses inhabit coastal ecosystems in temperate and tropical waters throughout the world, with both species diversity and population numbers highest (at least historically) in Asian and Latin American countries, along with Australia, New Zealand, and other tropical island states. The various species range in size from under an inch to more than a foot in height, and live from one to five years. With their unpalatable bony plates and spines, as well as effective camouflage, adult seahorses have few natural predators.
Seahorses pair-bond, with partners participating in daily interactions and elaborate mating rituals before the female deposits eggs into the male’s pouch. The eggs, depending on the species, gestate from two to six weeks, until as few as five to as many as 1,500 or more are born live during hours of labor, after which—often within a day—the male is “impregnated” again. Young seahorses are independent from birth; very few survive to adulthood.
While scientists have learned much about seahorse biology and ecology in the past two decades, much of the basic information about population distribution, range, numbers, trends, and the impact of trade on population viability remains unknown and, consequently, conservation efforts are hampered.
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species includes 38 seahorse species; 26 are listed as “data deficient” (i.e., insufficient information to assess status), 10 as “vulnerable,” one as “endangered,” and one as being of “least concern.” The IUCN identifies bycatch and/or unregulated take as the primary threat to nearly every species.
Precise numbers are difficult to obtain, but the vast majority of the seahorses in trade are used in traditional medicines. Such usage originated in Europe but today is centered in Asia—particularly, China. In addition, several hundred thousand to a million seahorses are traded annually as tourist curios—earrings, key chains, paper weights, and other trinkets—with a similar number of live seahorses obtained for aquariums. Virtually all of these animals are taken as bycatch from shrimp and prawn trawlers. As demand increases in concert with the booming Chinese and other Asian economies, captured seahorses are retained by fishermen to supplement their incomes.
Though the seahorse trade is centuries old, it wasn’t until the mid-1990s that Dr. Amanda Vincent, an expert in the international trade in seahorses and cofounder of Project Seahorse, published the first comprehensive assessment of the trade. Dr. Vincent estimated that, in 1996, approximately 45 tons (or 16 million seahorses) were being used in Asia alone. An estimated 24 million seahorses were traded internationally that year. The main exporting countries were Thailand, the Philippines, India, and Vietnam, while the primary importers were the then-British colony of Hong Kong and the countries of China, Taiwan, Japan, and Korea, with a total of 32 countries engaged in the trade. The United States and Europe were and continue to be major importers of live seahorses, primarily for commercial and private marine aquariums.
Since the mid-1990s, the number of seahorses in trade (domestic and international) has substantially increased, with estimates ranging from 24.5 million to more than 150 million now consumed annually by some 80 countries. Based on his undercover investigation in China, Kealan Doyle, a marine biologist and founder of Save Our Seahorses, reported in 2012 that 150 million seahorses are used annually in China alone as traditional medicine—seven times the official reported number. Doyle found that a single market in Guangzhou, China, sold 20 million seahorses a year. He visited stores that had, he estimated, 30,000 dead seahorses in bags piled from floor to ceiling—with 6,000 such stores in Hong Kong alone. This level of trade is unsustainable and, according to Doyle, could lead to seahorse extinction within a few decades.
Seahorses—dried, crushed, boiled, powdered, or fermented (initially live or dead) in alcohol—are used alone or in concoctions to treat a litany of conditions, including kidney ailments, stomach pains, baldness, tuberculosis, goiter, wounds, bone fractures, and as an aphrodisiac. In recent years, seahorses have been used as a growth stimulant in children, and by adults as an alternative to Botox treatments. For convenience, manufacturers of traditional medicines in Asia have incorporated ground seahorse powder into pills, making it more difficult to monitor the number of seahorses in trade. Medicinal products containing seahorses are also available in the United States. While empirical evidence that seahorses have a medicinal value is lacking, adherents of traditional medicine believe that centuries of such use is sufficient proof of the species curative powers—a belief that is leading the seahorse toward extinction.
Inevitably, such out-of-control trade has severe impacts on seahorse populations. In Asia alone, within a 10-year period beginning in the 1990s, seahorse populations had declined by an estimated 50 percent. Since then, scientists have expanded their research into the seahorse trade in Vietnam, Thailand, Malaysia, East Africa, Brazil and elsewhere in Latin America, documenting an expanding global trade. The evidence acquired reveals continued declining seahorse numbers with, in some cases, substantial localized declines if not extirpation.
In 2002 the entire seahorse genus (Hippocampus) was listed on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) to permit, but regulate, the seahorse trade. The Appendix II designation requires exporting countries to ensure the animals are legally acquired and that their removal will not be detrimental to the species in the wild. Recognizing the difficulty in making the required “non-detriment findings” (NDF), an interim, voluntary compromise was agreed to in 2005, whereby trade in wild-caught seahorses at least 10 centimeters (~4 inches) in height would be permitted in lieu of an NDF. It is unlikely that this compromise has benefitted seahorse conservation, as it is only voluntary, may not be adequately enforced, and does not address the significant amount of unreported trade and other anthropogenic threats to seahorse populations and their habitats.
An analysis of CITES international trade data maintained by the United Nations Environmental Programme – World Conservation Monitoring Centre reveals that over 32 million seahorses (live and dead) were exported by nearly 70 countries from 2004 through 2011. Over 31 million of these animals were captured in the wild. During that period, over 1¼ million seahorses were traded live for aquariums, with the rest (the vast majority) traded dead as curios or for traditional medicinal use. These numbers—though huge—represent substantial underestimates of the full scale of the trade, due to reporting deficiencies and also because these data do not include seahorses traded domestically or illegally.
The same database reveals that the United States imported nearly 600,000 seahorses from 2004 through 2011, including over 54 percent imported live. Of those live imports, more than half were captured in the wild with the remainder reportedly acquired from “captive” sources, being designated as either captive-bred, farmed, or ranched according to a CITES classification system. As is the case with many CITES species allegedly from captive sources, it is likely that wild seahorses are captured and illegally traded as captive-bred. In 2011 alone, over 72,000 seahorses were imported into the United States, with over half imported live—nearly 60 percent of those reportedly captive-bred or farmed. Over one-third of known imports were designated as illegal.
The precipitous declines in seahorse numbers have prompted efforts to preserve these unique species. Among the tools being used are the establishment of “no-take” marine protected areas, restrictions on the type and timing of fishing operations, and the development of seahorse aquaculture operations (both in and ex situ), which has led to a reported increase in the proportion of captive-raised seahorses in international trade. Though promising, none of these tools have been able to reverse declining population trends or meet the excessive global demand for seahorses.
Trade is not the only threat to seahorses, as their ocean habitat—primarily mangrove, sea grass, and coral ecosystems—are some of the most endangered in the world. Worldwide, over the past few decades an estimated half of all mangrove habitats have been destroyed; nearly 60 percent of coral reef habitat has disappeared, become degraded and/or fallen under imminent threat; and some 1,400 square miles of sea grass habitat has been lost. Such degradation—caused by coastal development, pollution, dredging, climate change, and destructive fishing practices that include the use of trawls, dynamite and poisons—are just some of the threats to the places seahorses call home.
Considering the cumulative impact of these environmental assaults and the seemingly insatiable human demand for seahorses, this unique and mythical creature with an anatomy as unusual as any creature created by Dr. Seuss, may be extinguished by greed, ignorance and vanity much sooner than predicted. Only time will tell.