In the Heat of the Reef: Cuttlefish Courtship Unveiled

Two hundred long strides under the scorching midday sun of Arabia separate the cool visitor’s room of the coast guard station—where the air conditioning is always on—from the liberating plunge into the waters of the Arabian Gulf. Before I even start, I’m already thinking about each step. Loaded with full diving and photographic gear, along with extra weights to help me sink in the highly saline water, my movement on the coral sand is slow and laborious. However, given the area's unpredictable weather and the fact that even the slightest change in currents can ruin the already mediocre underwater visibility, I dare not wait until the next dawn for another dive.

It’s late May, and the coral reef around the small island of Qaruh, near the Kuwait-Saudi Arabia border, has transformed into a battlefield of love. The water, which was just 13°C a few months ago, has already reached 31°C, creating the perfect conditions for the incubation of Pharaoh cuttlefish (Sepia pharaonis) eggs. Hundreds of males and females gather at the reef edges, where they will flirt and mate, completing their brief life cycle in the hope of passing on their genes.

Female cuttlefish are highly selective when choosing their mates, leading to fierce competition among the males. Often, more than one male will gather around a single female, competing in displays of size and determination to outshine their rivals. Typically, the largest male wins the contest, intimidating others with its striking colors and massive mantle. However, sometimes the victor is decided not by display, but by combat. Raising their tentacles, they expose their circular mouths and often bite each other, inflicting serious wounds on their opponent—a final escalation of the confrontation that usually lasts only a few seconds and determines the winner from the loser.

If the female approves of the duel's outcome, she will allow the victorious male to touch her mantle with his tentacles and claim her under his protection. From this point on, they will swim side by side, and at some point near sunset or early dawn, they will mate. The mating process can last from one to thirty minutes, during which the pair comes "face to face," intertwining their tentacles. The male cuttlefish uses his fourth tentacle to transfer spermatophores from his spermatophoric sac into the female’s mantle, fertilizing her eggs. The two cuttlefish will remain a pair for another two to three weeks until the female lays her eggs and attaches them to the underside of coral structures, hidden away in crevices, far from sight. A few days later, just eight months after their own birth, they will cease to live, having successfully fulfilled their biological role.

The coral reef at Qaruh, though small in size (the island covers just 35 acres), is an important breeding ground for many marine organisms in the northern Arabian Gulf. It remains in relatively good condition despite human pressures and periodic coral die-offs that occur in summer when water temperatures exceed 34°C. I reach the water, sweating, and soon find myself beneath the surface. I choose to move along the reef’s edge, at a depth of about 12 meters, beyond which the seabed becomes sandy-muddy and deepens sharply. In just the first minute of the dive, I spot my second encounter with cuttlefish, and at the edge of my visibility, I think I see another pair. Moving slowly and steadily, I manage to get very close and photograph them. The cuttlefish seem indifferent to my presence, continuing to flirt, fight, and mate undisturbed. The beats of their biological clock drown out the noise of my exhalation bubbles, reminding them that reproduction is the most crucial chapter in their short lives.

All photos and text ?Yiannis Issaris. The original greek article "The Fever of Reproduction" was published in Geodromio Magazine on 02/11/2013.