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Scientists Find Some Fish Capable of Body Size Awareness

24th September 2024
Bluestreak cleaner wrasse (Labroides dimidiatus), Red Sea, Egypt
Bluestreak cleaner wrasse (Labroides dimidiatus), Red Sea, Egypt Credit: Diego Delso/Wikipedia

Researchers have discovered that a small fish known as the cleaner wrasse will check its own body size before deciding whether to attack other fish or not.

The findings have been published in the journal Scientific Reports by a team at Osaka Metropolitan University in Japan.

As The Irish Examiner reports, Osaka Metropolitan University researcher Taiga Kobayashi has said that proof that fish can use the mirror as a tool can “help clarify the similarities between human and non-human animal self-awareness."

Chimpanzees, dolphins, elephants, pigeons and magpies are among a handful of species that have already pssed the mirror self-recognition (MSR) test, used for determining self-awareness.

This test involves putting paint or sticker marks on the body and placing the animals in front of the mirror to see whether they examine these marks.

Previous research has shown that cleaner wrasse can pass the MSR test, and the team wanted to know whether they can construct a mental image of their body after looking at themselves in the mirror, and then making decisions based on this mental representation.

A total of 15 cleaner fish were used in the test, seven of which had access to a mirror inside an aquarium .These fish were then presented with cut-out photos of a different group of fish that were either slightly (10%) bigger or slightly (10%) smaller.

The team found that the cleaner wrasse previously exposed to mirrors were less aggressive towards larger and same-sized fish in the photos but were more hostile towards the smaller fish.

The scientists conclude that cleaner wrasse may be capable of metacognition, as in an individual's ability to reflect on their thought process to plan and make decisions.

They suggest that further research is needed to confirm this.

Read The Irish Examiner here

Published in Marine Science
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Marine Science Perhaps it is the work of the Irish research vessel RV Celtic Explorer out in the Atlantic Ocean that best highlights the essential nature of marine research, development and sustainable management, through which Ireland is developing a strong and well-deserved reputation as an emerging centre of excellence. From Wavebob Ocean energy technology to aquaculture to weather buoys and oil exploration these pages document the work of Irish marine science and how Irish scientists have secured prominent roles in many European and international marine science bodies.

 

At A Glance – Ocean Facts

  • 71% of the earth’s surface is covered by the ocean
  • The ocean is responsible for the water cycle, which affects our weather
  • The ocean absorbs 30% of the carbon dioxide added to the atmosphere by human activity
  • The real map of Ireland has a seabed territory ten times the size of its land area
  • The ocean is the support system of our planet.
  • Over half of the oxygen we breathe was produced in the ocean
  • The global market for seaweed is valued at approximately €5.4 billion
  • · Coral reefs are among the oldest ecosystems in the world — at 230 million years
  • 1.9 million people live within 5km of the coast in Ireland
  • Ocean waters hold nearly 20 million tons of gold. If we could mine all of the gold from the ocean, we would have enough to give every person on earth 9lbs of the precious metal!
  • Aquaculture is the fastest growing food sector in the world – Ireland is ranked 7th largest aquaculture producer in the EU
  • The Atlantic Ocean is the second largest ocean in the world, covering 20% of the earth’s surface. Out of all the oceans, the Atlantic Ocean is the saltiest
  • The Pacific Ocean is the largest ocean in the world. It’s bigger than all the continents put together
  • Ireland is surrounded by some of the most productive fishing grounds in Europe, with Irish commercial fish landings worth around €200 million annually
  • 97% of the earth’s water is in the ocean
  • The ocean provides the greatest amount of the world’s protein consumed by humans
  • Plastic affects 700 species in the oceans from plankton to whales.
  • Only 10% of the oceans have been explored.
  • 8 million tonnes of plastic enter the ocean each year, equal to dumping a garbage truck of plastic into the ocean every minute.
  • 12 humans have walked on the moon but only 3 humans have been to the deepest part of the ocean.

(Ref: Marine Institute)

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