Shopping for new species | Hakai Magazine
The fish tale is legendary. On December 23, 1938, South African museum curator Marjorie Courtenay-Latimer received a phone call from her friend Hendrik Goosen, a trawler captain who often let her look in the day’s catch for something special. Goosen had just returned with a new trait, featuring a very unusual large fish which he thought would pique Courtenay-Latimer’s interest. It certainly is. The fish – blue at the time of capture, but dark gray by the time Courtenay-Latimer arrived – looked primordial and had odd fleshy fins. Biologist JLB Smith later identified the fish as a coelacanth, a species believed to have been extinct for over 66 million years. It was like dipping a net in the ocean and dredging a plesiosaur.
In 1997, nearly 60 years after the rebirth of the coelacanth, a second species of coelacanth was spotted by biologists at a fish market in Sulawesi, Indonesia. This discovery and others like it have made fishermen and fish markets important sources of information for marine biologists eager to discover new species. The world’s oceans are so vast and deep that keeping an eye on what’s on the market can alert biologists to species they would likely be unable to spot or distinguish in the natural habitats of animals.
It can be a bit slippery, says Sarah Tucker, a researcher at the Hawai’i Institute of Marine Biology. “Markets can be difficult because the fish often come from different places and exchange hands between many different fish collectors,” she says.
Obtaining accurate and critical information about where a fish was caught can be difficult in such circumstances. Some researchers develop relationships with specific fishermen, just like Courtenay-Latimer, to help gain essential information about where the fish are caught. More than that, Tucker adds, “talking to local fishermen and fish collectors can be very helpful in understanding what they are seeing and the local names of these species.”
Sometimes the presence of something new on a trawler or in a market is obvious. In 2018, marine biologists named a new species of deep sea shark, Planonasus indicus, which first caught the attention of researchers in a market near the southwest coast of India.
But many new species of fish are cryptic, difficult to distinguish based solely on anatomy. To get around this problem, biologists often study fish in markets using DNA barcodes, an effort that sometimes reveals previously unknown species, such as a new deep-water snapper named earlier this year. “It is becoming more and more common in scientific publications that you need both genetic and morphological analyzes,” says Tucker, genetic clues sometimes being the first clue that there is something new among the stalls. fish markets.
And biologists aren’t just interested in fish.
“We prefer to buy fish species that have not yet been studied intensively, or not at all, if our goal is to find new species of parasites”, explains parasitologist Stefan Theisen of the University of Rostock in Germany. The fact that fish tend to have species-specific parasites means that newer fish likely have new parasites, he adds, with specialists checking anatomical hotspots like the heart and esophagus for tiny hangers. Usually, Theisen adds, a sample of around 35 fish is needed to detect any parasites that might affect this species, which means a lot of time fishing among the stalls for something remarkable.