//
you're reading...

Behavior

Loud and Order: How reef fish vocalize to keep schools cohesive

 

 

Article: van Oosterom, L., et al. “Evidence for contact calls in fish: conspecific vocalisations and ambient soundscape influence group cohesion in a nocturnal species.” Scientific reports 6 (2016).

Background:

Vocal signals are a critical form of communication for many animals, and are often used as contact calls to maintain group cohesion when individuals start to disperse too much. We’ve all heard teachers shouting out instructions for us to stay in our single file lines, but even other animals use vocalizations to keep group cohesion; for example, chimpanzees use vocal calls targeted to family members and allies to stay in close proximity (Fig. 1). Caimans, relatives of crocodiles, increase sibling cohesion by using vocalizations, and dolphins alter their sounds based on how dispersed their group is. Maintaining group cohesion via vocal signals has been observed in a wide range of animals, but has never been directly observed in fish.

Fig. 1: Many animals, like chimpanzees, keep group order and cohesion by using vocal signals.

Fig. 1: Many animals, like chimpanzees, keep group order and cohesion by using vocal signals (Photo: John Mitani, via BBC).

The ability of fish to produce sound and vocalize is well known, and we recently discussed how fish can use sound to attract mates or in territory disputes. In addition to vocalizing, we know many fish species aggregate in schools as a way of avoiding predators or foraging for food (Fig. 2). We know that schools are often maintained by visual cues, like seeing a large predator nearby, or hydrodynamic cues (like movement

or chemical cues in the water), which can be helpful when visual cues are limited. It would make sense, then, that some fish species, particularly those nocturnal ones (active in the absence of light), would use vocal signals to help maintain the cohesion of a school. If fish do use vocal signals for group cohesion, this would mean that fish would then be the oldest evolutionary group to have evolved this ability, helping in our understanding of how communication between groups of animals came to be. With this in mind, researchers from New Zealand tested whether or not vocalizations were used by the New Zealand bigeye (Pempheris adspersa) in relation to school cohesion (Fig. 3 and 4).

Fig. 2: Fish group together in schools like this to combat predation or to forage (Photo: via Azula).

Fig. 2: Fish group together in schools like this to combat predation or to forage (Photo: via Azula).

Fig. 3: Pempheris adspersa, the New Zealand bigeye.

Fig. 3: Pempheris adspersa, the New Zealand bigeye (Photo: Scott Hunt).

Fig. 4: Bigeyes school together when hiding during the day and when foraging at night.

Fig. 4: Bigeyes school together when hiding during the day and when foraging at night (Photo: sea friends.org.nz).

 

 

 

 

 

 

 

The Study:

Divers collected bigeyes off the coast of New Zealand and brought them to a laboratory where their groups and vocalizations could be tested. Groups of 24 individuals were used in large aquarium tanks rigged with advanced, underwater speakers, recorders, and cameras. Researchers first wanted to see how these fish responded to increasing levels of ambient coastal sounds. Fish were played 10 minutes of ambient sounds followed by 10 minutes of silence. During the 10 minutes fish were played sound, school cohesion (determined by the area occupied by the 24 fish) was high. But when the sounds were turned off, dispersal of the school drastically increased (Fig. 5), and in some cases, the amount of vocalization increased. Here, fish are sticking together in a noisy environment.

Fig. 5: This graph show the group cohesion based on 3 levels of ambient sound, both during and after the sounds are played. The black bars show that cohesion is higher when ambient sounds are turned off.

Fig. 5: This graph show the group cohesion based on 3 levels of ambient sound, both during and after the sounds are played. The gray bars show that cohesion is higher when ambient sounds are on.

Researchers also tested how the fish schools responded to vocalizations by their own species, they did this by playing previously recorded bigeye sounds. When played these recordings, the 24 fish were found to increase their cohesion and also were more vocal themselves (Fig. 6 and 7). Basically, these fish become more cohesive when they can hear one another, direct evidence of vocalizations being used to keep the school together.

Fig. 6: This figure shows group cohesion, here when sounds of their own species are played, the groups stick closer together.

Fig. 6: This figure shows group cohesion, here when sounds of their own species are played, the groups stick closer together.

Fig. 7: When hearing vocalizations of other bigeyes, these fish become more actively vocal themselves.

Fig. 7: When hearing vocalizations of other bigeyes, these fish become more actively vocal themselves.

 

 

 

 

 

 

 

 

 

The Significance:

Never before have vocalizations used as contact calls been observed in fish. While contact calls have been observed in many other animals, finding it in fish highlights that this is the oldest evolutionary group to employ this method of cohesion. This study shows a new way in which fish can utilize sounds cues, rather than finding a mate or defending territory: fish use sound to make sure their group stays together. Studies like this show how researchers can use cutting edge audio technology in novel ways to uncover new behaviors in fish, opening the door for many future studies.

 

Discussion

No comments yet.

Post a Comment

Instagram

  • by oceanbites 3 months 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 4 months 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 5 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 6 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 6 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 7 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 7 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 8 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 8 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 8 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 8 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 9 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 9 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 9 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 10 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 11 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 11 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 12 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 12 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 1 year 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