Poaching a source of many 'ōpae 'ula sold as aquarium pets

Many of the tiny Hawaiian red shrimps, or 'ōpae 'ula sold in the aquarium trade appear to be poached wild animals, illegally taken in some cases from conservation zones or without proper permits.

(Image: The native 'ōpae 'ula are less than a quarter-inch long as adults. Photo courtesy Scott Santos.)
The harvesting could deplete wild populations and threaten a unique Hawaiian ecosystem, according to researchers David A. Weese and Scott R. Santos, of the Department of Biological Sciences and Cell & Molecular Biosciences Peak Program, at Auburn University in Alabama.

Santos has long studied the life in Hawaiian achialine ponds, including the little Halocaridina shrimps. Anchialine ponds are coastal pools that have no surface connection to the sea, but have various levels of salinity and may rise and fall with the tides. In Hawai'i, most of them are found along the Kona and Ka'u coast of the Big Island and in the 'Ahihi-Kina'u Natural Area Reserve on Maui, although there are also ponds on O'ahu.

The research team had previously done DNA analysis of the various Hawaiian native shrimp populations, and found that the shrimps in different areas are sufficiently unique that they can be distinguished from one another by region.

For this work, published in the February 2009 issue of the journal Animal Conservation, they collected shrimps being sold in the aquarium trade and compared their DNA with those previously studied.

What they found is that most of the shrimps are from the Big Island, where a few people have permits to collect them, but a few aquarium shrimps are from Maui, where there are no existing collecting permits.

“A bunch of red flags went up when those Maui animals showed up in the analyses,” Santos said in an email to RaisingIslands.

Is it possible that all or most of the shrimp being sold in stores and on the Internet are being captive-raised—meaning there are no new collections in the wild? Theoretically possible, but unlikely, although some certainly are, Santos said.

“I would be willing to bet that the vast majority of opae ula out there were taken directly from anchialine ponds rather than raised in captivity,” he said.

“While I wouldn't be surprised if some of the animals in the aquarium trade are from reproduction within a captive setting (I know a shrimp hobbyist in California that sells some of juveniles from animals he breeds to other hobbyists on the Internet), conditions at none of the aquarium shops in Hawaii that we bought animals from are conducive to captive husbandry,” Santos said.

There are a few Big Island collectors who are annually renewing their collection permits. In some cases, those collectors (and possibly people without permits) are hiking miles across Ka'u lavas to find pools with enough shrimp to scoopnet.

But Maui is a different story. Even if the collecting there is being done on private land rather than within the protected Natural Area Researve, it appears to be illegal, Santos said.

“The animals that trace their history back to 'Ahihi-Kina'u on Maui are a sticky point.

“On one hand, it appears to be a case of poaching since most of the anchialine pools in the area are either in the 'Ahihi-Kina'u Natural Area Reserve (which was established in the late 1970s) or on private property.

“On the other hand, if the collections are taking place on private property by its owner, the individual(s) doing them is still required to have an active commercial fishing permit since they are selling the animals. Last I checked, no one on Maui had a permit, which raises all kind of issues,” Santos said.

The Halocaridina shrimps are popular in the aquarium trade because they come in colorful orange color, they're cute, they're hard and long-lived, and they take little care. They can live for years in a properly set-up glass dome without additional food.

But they are also sold as live fish food. And that's a traditional Hawaiian use—they were collected by 'ōpelu fishermen to attract the fish.

And the shrimps are part of an international network of trade in marine creatures.

“It is conservatively estimated that 1471 fish, 140 stony ... coral and over 500 other invertebrate species are traded as marine ornamentals on a yearly basis, with most being stocked from wild caught specimens,” Weese and Santos write in the Animal Conservation piece.

Previous work has identified at least 13 different unique kinds of Halocaridina, each of which is found on only one island. Many of the O'ahu pools occurred in the limestone sinkholes of the 'Ewa district, and most of them have already been destroyed for agriculture and development. Hotels have been built over anchialine ponds on other islands.

“Commercial harvesting, coupled with habitat destruction as well as strong regional endemism, could lead to the depletion and/or extinction of unique Halocaridina populations or genetic groups,” the authors write.

©2009 Jan TenBruggencate