Tool-Using Fish Species Found in the Laccadive Sea

• 17 Apr 2024

Source: TH

Why in News?

Recent findings indicate that three fish species (Jansen’s wrasse, checkerboard wrasse, moon wrasse) in the Laccadive Sea, off the southwest Indian coast, exhibit tool-use capabilities.

Which are the Three Tools Using Fish Species?

• About:
  • While primates, birds, otters, octopuses, and many other animals are known to be capable of using tools.
    • The use of tools by fish seems impossible, as they lack hands, claws, or tentacles to grasp and manipulate objects.
  • However, the three fish species use live or dead coral structures as anvils to break the hard shells of sea urchins so they can get to the edible bits inside.
    • The Jansen’s wrasse (Thalassoma jansenii) and the checkerboard wrasse (Halichoeres hortulanus) have never been reported using tools before.
    • On the other hand, this is the first documented instance of the moon wrasse (Thalassoma lunare) using tools in the wild.
• Sea Urchins & the Discovery:
  • Due to their spiny, hard shells, only a limited number of fish could consume E. molaris sea urchins.
  • However, Jansen’s, checkerboard, and moon wrasses were observed using tools to crack open the urchin skeletons, much like cracking open a walnut shell.
  • Wrasses don't have specialised mouthparts like archerfish (tool using fish), so they use clever behaviours to eat burrowing sea urchins.
    • They carefully turn the urchin over to reach its softer underside, then crack it against hard coral to eat the soft parts inside.
    • Wrasses use the coral reef both as a tool to flip the urchin and to crack it open for food.
• Importance of the Findings:
  • Scientists have only observed anvil use in about 18 fish species worldwide, all from the Labridae family.
    • The recently discovered three tool-using species also belong to the same family.
  • These fish prey on invertebrates such as crabs, clams, and urchins and vertebrates like baby sea turtles, but their sizes, approaches, prey handling, and locations differ.

Which Other Marine Species Use Tools?

• Octopuses: These cephalopods are known for their exceptional problem-solving skills and tool use.
  • They have been observed using coconut shells and other objects for shelter, dragging around discarded shells for protection, and even dismantling and reassembling equipment in aquariums.
• Dolphins: Some dolphin species use marine sponges to protect their rostrums (snouts) while foraging on the seafloor.
  • This behavior, known as "sponging," is a form of tool use unique to certain populations of dolphins.
• Sea Otters: These mammals are known to use rocks and other hard objects as tools to break open shellfish, such as clams, for food.
  • They typically place the rock on their chests and use it to smash the shell against, known as an anvil technique.
• Fish: The blackspot tuskfish, found in coral reefs, demonstrates learning and adaptability by using rocks to open clamshells, similar to how archer fish use water jets to shoot down prey above the surface.

UPSC Civil Services Examination, Previous Year Question (PYQ)

Prelims:

Q. Consider the following kinds of organisms: (2021)

1. Copepods
2. Cyanobacteria
3. Diatoms
4. Foraminifera

Which of the above are primary producers in the food chains of oceans?

(a) 1 and 2
(b) 2 and 3 
(c) 3 and 4
(d) 1 and 4

Ans: (b)

Q. With reference to the evolution of living organisms, which one of the following sequences is correct? (2009)

(a) Octopus – Dolphin – Shark
(b) Pangolin – Tortoise – Hawk
(c) Salamander – Python – Kangaroo
(d) Frog – Crab – Prawn

Ans: (c)