Kochi, May 19 (IANS) A groundbreaking study by ICAR-Central Marine Fisheries Research Institute has uncovered remarkably complex mating behaviour in the Indian squid (Uroteuthis duvaucelii), documenting for the first time evidence of both heterosexual and homosexual mating patterns in the species found in the Arabian Sea.

The research, carried out by scientists from the institute’s Shell Fish Fisheries Division, offers fresh insight into the reproductive biology of one of India’s commercially important squid species and could have significant implications for fisheries management and marine conservation.

Led by researchers Dr Geetha Sasikumar and Dr K K Sajikumar, the study examined squid samples collected from waters off Kochi. Analysis of 232 female squids revealed that nearly 40 per cent carried spermatangia, sperm-containing structures attached to their buccal membranes, a fleshy area surrounding the mouth.

According to the researchers, the findings indicate that mating activity occurs throughout the year, with peak reproductive activity observed during October.

In a particularly striking discovery, scientists also identified spermatangia implanted on the buccal membrane of a male squid, providing the first documented evidence of same-sex sexual behaviour in Indian squid.

While similar behaviour had previously been reported among certain deep-sea squid species outside Indian waters, scientists had largely attributed it to low-visibility environments in the deep ocean.

The new finding marks the first such documented instance involving a coastal squid species.

The study, published in the Journal of Natural History, also revealed that Indian squid begin mating at a surprisingly early stage of life.

Using statolith analysis, a technique comparable to reading growth rings in fish, researchers estimated that mating may begin as early as 98 days after hatching.

Another significant observation was the large number of sperm packets attached to individual females.

In one case, researchers counted as many as 385 spermatangia around a single female squid’s mouth region, suggesting repeated mating with multiple males before egg laying.

Scientists believe such behaviour may be linked to dense spawning aggregations where mating interactions become highly opportunistic and competitive, potentially contributing to the species’ rapid growth and reproductive success.

Researchers said understanding the squid’s mating system is vital for improving stock assessments and designing sustainable fisheries management strategies, especially at a time when squid resources are becoming increasingly important to India’s marine economy.

They have also called for further behavioural and physiological studies to better understand the species’ reproductive dynamics and ecological adaptations.

–IANS

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