July 12, 2011
Everyone knows the tiger, the panda, the blue whale, but what about the other five to thirty million species estimated to inhabit our Earth? Many of these marvelous, stunning, and rare species have received little attention from the media, conservation groups, and the public. This series is an attempt to give these 'forgotten species' some well-deserved attention.
The 'cool' spotted handfish: adult and juvenile. Photo by: Mark Green - CSIRO.
Handfish, as they are aptly known, have hand-shaped pectoral fins that allows the fish to quite literally walk along the bottom of the sea searching for tantalizing worms and crustaceans. Perhaps this is not as surprising as it first sounds: pectoral fins are thought also to have evolved into the forelimbs of everything from rats to frogs to lizards. So, walking on fins is little different from walking on legs, though much rarer today. Fifty million years ago handfish were present in many of the world's oceans, but today there are only 14 species left--nine of which were only described only last year--and they are solely found in the waters around Australia. Handfish are a unique branch of the much more widespread anglerfish: characterized by a fleshy tip on their head which is used to attract prey.
One of the most spectacular species is the spotted handfish (Brachionichthys hirsutus). With a mohawk-like angler, a wild pattern of spots or stripes, and a glum expression, the spotted handfish looks like the fish-version of a rebel from the 50s: they have a James Dean or young Elvis quality about them.
Spotted handfish. Photo by: Mark Green - CSIRO.
But the spotted handfish has another claim to fame, according to Green: "It is recognized as the first marine fish to become threatened with extinction."
The spotted handfish is listed as Critically Endangered by the IUCN Red List, the most dire rating before extinction. Found only in Tasmania's Derwent estuary, the spotted handfish was once considered common but by the mid-1990s it had nearly totally vanished.
"When I first started working on this project in 1997 only 6 spotted handfish had been seen during the pilot project (a broad scale search) in the year before. This was just after listing [the fish as endangered] and it was all pretty much a big unknown. Myself and Barry Bruce started diving in areas where the six specimens had been found, our aim was to try and locate a breeding colony so we could begin collecting basic biological information about reproduction and start mapping the population," says Green. "We did a few dives without seeing any handfish, and then when we did find one it was very exciting. There were underwater high fives and lots of underwater yahoos. Once we had located one fish it was just a matter of expanding the search in the general area to find others during more dives. Of course, that was just the start of the project, and using this method we have located nine restricted locations that have local populations of spotted handfish."
In total researchers estimate a global population of around 2000-3000 individuals. Unfortunately some of the populations are so isolated it is impossible for them, without human intervention, to mix with others. In addition, one of the handfish communities completely vanished between 1999 and 2005.
"We don't know why this local extinction happened as we didn't have the resources to monitor the site during the intervening period," says Green.
After a decade and a half researchers remain uncertain as to why the species has fallen so far, though they suspect a number of human impacts are plaguing the fish.
Spotted handfish with seastar behind it and sea tulips to the left. Photo by: Mark Green - CSIRO.
One can almost imagine the spotted handfish spouting out to the human community (with James Dean's characteristic passion): 'You're tearing me apart!' But to our credit the human community is trying to save the species.
Efforts by the Derwent Handfish Recovery Project include continued monitoring of spotted handfish populations, captive breeding, and creating artificial spawning sites to make up for the decline of sea tulips in the area. Captive breeding to date has proven difficult. After years of little success, researchers were able to release 155 captive-reared spotted handfish in 1999. The fish were tagged and two weeks later researchers located 5 of them. Yet in later dives the researchers were unable to find a single tagged handfish, perhaps implying a high mortality of the captive-bred individuals. Artificial spawning sites have shown more success with researchers believing that it has been effective in expanding spawning sites. A number of organizations have provided further support for the spotted handfish, including the Reef Life Survey, Aquenal Pty Ltd, Veolia Environmental Services, Institute of Antarctic and Marine Studies, and funding from the government grant program, Caring for our Country.
Green says the public can help save the spotted handfish by "not contributing to any of the threatening processes" such as illegal collection. In addition, concerned citizens should "[petition] the governments for better resources to be allocated to research and protect the three handfish species listed as threatened." On top of the spotted handfish, the Australian government considers the red handfish (Thymichthys politus) and the Waterfall Bay handfish (Brachiopsilus ziebelli) as Vulnerable to extinction. Though much remains unknown about the spotted handfish, even less is known about most of the world's other handfish species. More research is needed if the whole handfish family is not to disappear.
Green, who monitors the spotted handfish regularly, says, " I still get excited every time I find a spotted handfish as they are just so cool."
A perfect way to describe a little rebel of a fish.
A spotted handfish hanging out in the mud. Photo by: Mark Green - CSIRO.
Female spotted handfish guarding eggs laid on a sponge. Photo by: Mark Green - CSIRO.
Eggs laid on a sea tulip. Photo by: Mark Green - CSIRO.
Close-up of female and eggs. Photo by: Mark Green - CSIRO.
A last look at the spotted handfish. Photo by: Mark Green - CSIRO.
To discover more of the world's forgotten species: Click Here.
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