Context:
Recently, marine biologists at the University of Southampton have developed a technique to decode the chemistry of otoliths.
Relevance:
GS III: Species in News
Otolith Rings: Nature’s Age and Environment Tracker in Fish
Composition and Location:
- Otoliths, often referred to as “earstones,” are calcified structures found in the ears of bony fishes. They serve as unique indicators of a fish’s age and environmental experiences.
Age Revelation Through Rings:
- Similar to tree rings, otolith rings disclose the age of a fish. These rings form over time, creating identifiable layers.
Environmental Clues:
- Isotopes of oxygen within otoliths indicate the temperature a fish encountered during its life. Carbon isotopes offer insights into the conversion speed of food into energy.
Fitness Tracker for Fish:
- Otoliths act as fitness trackers for fish, providing essential data for their well-being. These stony structures are located behind the fish’s brain.
Types of Otoliths:
- Sagitta: The largest among the three pairs, sagitta aids in sound detection and the hearing process.
- Asteriscus: Also involved in sound detection and hearing.
- Lapillus: This otolith type contributes to sensing gravitational force and sound.
Diversity Among Species:
- Different fish species exhibit otoliths of distinct shapes and sizes. Cartilaginous fishes like sharks lack otoliths.
Significance in Identification:
- Otolith features help identify fish species, determine size, age, growth rate, and even the season of death for an individual fish.
Environmental Insights:
- Analysis of otolith oxygen isotope values provides data on the water temperature where the fish resided.
- Concentrations of trace elements, such as barium, in otoliths offer clues about the water’s salinity levels.
-Source: The Hindu
