By Xiong Zhang
In a recent post, I wrote about how fishers have much to contribute to the science, conservation, and management of fish populations. As a young marine biologist I’m keen to learn from anyone and everyone, including these often-overlooked ‘experts,’ so beginning this April I’ve been interviewing fishers across China about seahorses. The goal of my research (funded by Disney) is to establish a baseline knowledge of the country’s seahorse populations.
After nearly three months and hundreds of interviews, I’m even more convinced of the importance of fishers’ knowledge.
At first I was afraid that they would not bother to talk with a stranger from a world far away from their own. But when I started to chat with some locals the first day at a fishing port in Linshui County, Hainan Province, I was surprised at how open and welcoming some of them were.
Generally, I interviewed two types of fishers. The first is commercial, and the other small-scale. Commercial fishers are those working on large fishing vessels (~ 15 to 50 m by length) who go fishing far away from the port. They are usually hired by a wealthy businessman who owns the vessel and has direct ties to the seafood business. The crews of five to 10 people consist of captain, a chief engineer, and a few fishers on deck. It is the fishers who operate the nets and collect and sort the catch. Commonly used gear that catch seahorses are shrimp trawls and drift gillnets.
These workers, with a monthly salary of US $700 to $1200, catch seahorses as bycatch (i.e. the seahorses are caught incidentally as part of a targeted catch of species such as shrimp or crab), collect them from the nets, and sell them to local traders for extra income back at the port. Sometimes the ship captains are part of this “seahorse bonus” scheme, especially when the seahorses are abundant and the fishers directly target them in specific waters, such as Zhoushan Fishing Ground (close to the estuary of the Yangtze). The fishers know where and when to catch the seahorses, but they have little ability to discriminate between species — to be honest, this is not easy even for an expert. Unlike us scientists, who name seahorses with Latin words, the fishers give seahorse species common names based on their size or the color. Not necessarily the best way to differentiate species. Their knowledge usually ends there, though some fishers have been able to provide me with a rough map of seahorse population distributions.
The second type, small-scale fishers, are those who own a small fishing boat, usually a wooden vessel no longer than 10 m, and only fish in coastal waters close to their fishing port or village. There are usually two or three fishers – often from the same family – working on each boat, with a total annual income of between US $10,000 to $20,000. They catch seahorses with many different types of gear. The most frequently used are shrimp traps, shellfish trawls, crab traps, and drift gill nets. Although they catch many fewer seahorses than their commercial counterparts, they tend to know a lot about seahorse behavior and ecology.
Here are a few of their insights: that some seahorse species hide in the rocky seafloor, between the gaps between shellfishes (e.g. mussels), and in empty shells; that other seahorses prefer to live on muddy seafloor with seagrass or macroaglae in estuaries; that they sometimes drift to shore with their holdfasts (e.g. seagrass) in summer, while the autumn tides drive them to deep water; that wild seahorses can make a “goo-goo” sound, which I’d only ever heard about from some aquaculture literature.
A few fishers I met even tried to culture seahorses because their children love them, and from their experiments learned how seahorses swim and how they give birth. One fisherman in Shandong Province claimed that he cultured what was probably a Japanese seahorse (H. mohneikei) in a small plastic bottle for more than one month in spring without feeding but only changing water every three days. (More likely the seahorse was feeding on zooplankton already in the bottle, but an interesting anecdote nonetheless!)
My interviews with Chinese fishers are not yet finished, but I’m already confident that their knowledge will inform the science, conservation, and management of seahorses in China.
Xiong Zhang is a PhD student with Project Seahorse. Follow him on Twitter @Harry0130.