//
you're reading...

Behavior

To communicate with members of its own species, flashlight fish uses a special type of morse code

Jägers, P., Wagner, L., Schütz, R. et al. Social signaling via bioluminescent blinks determines nearest neighbor distance in schools of flashlight fish Anomalops katoptron. Sci Rep 11, 6431 (2021).

Below a flashlight fish’s eyes is an organ that provides the ideal conditions for a special partnership. Bioluminescent bacteria live inside these organs. Here bacteria find the necessary nutrients to grow and reproduce. Flashlight fish cannot control how much light is created by these bacteria. However, it does have special flaps that block the bioluminescent light. According to a new study published in Scientific Reports in March of 2021, the blinking patterns of this fish are used to communicate with members of its own species.

Flashlight fish, Anomalops katoptron. Credit: Wikimedia Commons

To find out how flashlight fish communicate with members of their own species, scientists conducted three separate experiments – two in a lab, and one in the wild. First, they placed a fish dummy inside a tank and introduced a single flashlight fish inside the tank. The faster that the fish dummy flashed its lights, the closer the flashlight fish stayed to the test dummy. In a second experiment, scientists placed thirteen LED lights around a circular tank and turned them on one after the other. Flashlight fish followed the LED lights and moved faster when the LED light flashed at a faster interval. From these two experiments, scientists determined that flashlight fish use light to follow fish of their own species and that fast blinking patterns are a signal to move faster and stay closer to other fish.

These two findings are important for two main reasons. First, flashlight fish spend most of their time in dark underground caves and holes in the ocean. They come out to the surface to feed on zooplankton during dark moonless nights. Therefore, in such dark settings, light is an important way to communicate with members of its own species. Second, flashlight fish are a type of schooling fish. When schooling fish feel threatened by a predator they stay close to one another and move quickly. The fast blinking pattern is one way in which flashlight fish signal other members of the species that danger is looming.

School of Flashlight Fish. Credit: RUB, Department of Zoology and Neurobiology, Stefan Herlitze

Diving at night off the coast of Indonesia, scientists waited for a school of flashlight fish to get close so that they could test their experiment in the field. Once the fish were close, they startled the school of fish using red dim lights and filmed their escape. From the film, scientists confirmed what they had seen in the lab – the fish blinked faster and stayed closer together.

In ray-finned fish, the largest group of fish, bioluminescence has evolved independently at least 27 times. However, the majority of these bioluminescent fish live in deep areas where it is difficult for scientists to do experiments. While flashlight fish are closely related to deep bioluminescent fish, they live in relatively shallow waters. Thus, they are the perfect species to study so that we further our understanding of bioluminescence and learn how fish survive in dark areas of the ocean.

Discussion

No comments yet.

Post a Comment

Instagram

  • by oceanbites 2 weeks ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 1 month ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 2 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 3 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 4 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 4 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 4 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 6 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 7 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 7 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 8 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 8 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 9 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 9 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 10 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com