Japanese Tech is Fishy
Scientists have succeeded in getting salmon to give birth to trout. Whilst the research is likely to have male salmon the world over sticking close by their mates and suspiciously eyeing any passing trout, conservationists and fish-eaters are hailing the breakthrough as a masterpiece of weird science.A team from Tokyo University have perfected a technique for inserting the eggs and sperm of one species of fish into surrogates of another species. They hope that their technology will eventually help to preserve stocks of fish such as the endangered bluefin tuna and sturgeon.
The team injected sperm stem cells from a male trout into sterile salmon. These cells then matured within the salmon producing mature trout sperm. What’s even more incredible is that the stem cells can be injected into sterile female salmon to produce eggs. The cells are still at an early enough stage in their development to switch from being sperm to eggs. (What is a stem cell?)
The young produced were genetically verified as 100% trout. The research team, led by Associate Professor Goro Yoshizaki, have dubbed their method "surrogate broodstocking".
Conservationists have been quick to spot the potential of the technology and are rapidly formulating plans to engineer the recovery of rare salmon as well as sturgeon, paddlefish and a host of other endangered fish species.The Japanese team also have conservation on their minds… well in a roundabout way. Their main focus is now to transfer the technology out of trout and into tuna. They hope that they will be able replenish stocks of bluefin tuna, whose population has been decimated by 97% over the last few decades.
Being a thousand times smaller than adult tuna and therefore somewhat easier to manage, it is hoped that the mackerel will play surrogate parents to millions of baby tuna, safeguarding the future of one of Japan’s favourite dishes.
Across the Pacific, US scientists are gearing up for their own project using salmon and trout. However, this time the roles will be reversed with brown trout playing mummies and daddies to sockeye salmon – a species listed as endangered in Idaho, Oregon and Washington states.
The new method is "one of the best things that has happened in a long time in bringing something new into conservation biology," according to zoology professor Joseph Cloud of the University of Idaho, who is leading the U.S. government-funded sockeye project.
Many people will now be interested in how the technology might be used to help species other than fish. However, the techniques don’t easily cross to mammals, for instance. One of the reasons that the system works so well with fish is that they lay lots of tiny eggs; therefore you can have a mackerel laying tuna eggs. It wouldn’t be fair, however, to make a domestic moggy give birth to a tiger.
If we've whetted your appetite for fishy science, catch a couple of these articles:
- Weird - Jellyfish grow twelve heads
- Cool - Little squirt's big potential
- Nicely - Jellies gee up Japan
- Nastily - The fish that swims up your willy
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