Variations in Ear Bones of Garfish from the Central Mediterranean Sea

Jenn Hoskins
12th March, 2024

Variations in Ear Bones of Garfish from the Central Mediterranean Sea

Key Findings

  • Study from the University of Messina details the ear bones of Mediterranean garfish for the first time
  • Garfish otoliths (ear bones) are symmetrical, with no differences found between sexes or body sides
  • Otolith shapes and sizes vary with fish size and geography, suggesting environmental adaptation
Understanding the tiny ear bones of fish, known as otoliths, has become a significant focal point in marine biology. These structures are not only critical for fish balance and hearing but also carry invaluable biological and ecological data. The recent research conducted by the University of Messina dives into the otoliths of the garfish (Belone belone), a commercially valuable and ecologically important species in the Mediterranean and eastern Atlantic[1]. This study is crucial as it fills a gap in our knowledge about the otoliths of this species, particularly the asterisci and lapilli, which had not been described for Mediterranean populations before. Otoliths come in three pairs: the sagittae, the lapilli, and the asterisci. Each pair has a unique role in the fish's vestibular system, which governs balance and spatial orientation. The sagittae are the largest and most studied otoliths, often used for age determination and to study fish life history. The lapilli and asterisci are smaller and less understood. Previous studies have suggested that otolith shape and size could vary between species and even among individuals of the same species due to factors like habitat and life habits[2][3]. The University of Messina's study aimed to provide a detailed description of these three otolith pairs from the Mediterranean garfish. The researchers meticulously analyzed the morphology (shape and structure) and morphometry (measurements) of the otoliths, searching for patterns of variability within the species. Their analysis included advanced imaging techniques, which allowed them to capture the intricate details of these tiny structures. One of their key findings was the absence of directional bilateral asymmetry and sexual asymmetry in the otoliths. This means that the otoliths were generally symmetrical, regardless of which side of the body they came from or the sex of the fish. This finding is consistent with the notion that otoliths develop in a stable and consistent manner within a species, although slight differences between left and right otoliths have been observed in other species[2]. The study also noted that the morphology and morphometry of the garfish's otoliths differed from those described in previous literature. This suggests that there may be geographical variation in otolith characteristics, influenced by genetics and environmental conditions. For example, the garfish's wide distribution range could mean that different populations have adapted their otoliths to local conditions. Furthermore, the researchers observed enhanced variability in the shape and size of the sagittae between different size classes of garfish. This indicates that as garfish grow, their otoliths may change in response to their changing environment and lifestyle. This aligns with the sensory drive hypothesis, which posits that environmental factors can shape the evolution of sensory structures[4]. The variations in otolith shape among different rockfish species, influenced by ecological and biogeographical factors, lend support to this hypothesis[4]. The University of Messina's study contributes to our understanding of otolith variability and confirms the reliability of shape analysis as a tool for studying fish biology. By showing that otolith features can vary based on geography and fish size, this research adds another layer to our understanding of how these structures can reflect the life history and habitat of fish. In conclusion, this study not only provides the first detailed description of the otoliths of the Mediterranean garfish but also highlights the importance of considering environmental and life habit variations when studying otoliths. The findings from the University of Messina pave the way for future research into how these small but significant structures can help us better understand the lives of fish in our oceans.

Animal ScienceMarine BiologyEvolution


Main Study

1) Intra-population variability of the saccular, utricular and lagenar otoliths of the garfish Belone belone (Linnaeus, 1760) from South-Western Ionian Sea (Central Mediterranean Sea).

Published 11th March, 2024

Related Studies

2) Intra- and interspecific variability among congeneric Pagellus otoliths.

3) Enigmatic ear stones: what we know about the functional role and evolution of fish otoliths.

4) Otolith shape lends support to the sensory drive hypothesis in rockfishes.

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