Report on the spawning of Sargassum fish, Histrio histrio

The fishes were collected from the floating/drifting sargassum weeds off Vizhinjam coast (South west coast of India, Near Kovalam Beach) to the marine aquaria and Research Centre of Central Marine Fisheries Research Institute, Vizhinjam. Fishes (6-8) were kept in 5 ton circular FRP quarantine tanks for their forward transition to the exhibit tanks. Two of the fishes were observed to have highly inflated abdomens. The second evening between 1600 -1630 hrs there was a splashing sound in the quarantine tank and upon inspection a transparent gelatinous object was found. It was found floating on the water surface (see photographs below). The egg mass/raft appeared to be double layered with slightly larger middle region and blunt ends at both sides. The length of the egg mass/raft was found to be about 30-35 cm. The egg mass/raft was transferred to a 500 L tank in a flow though system after an hour. Moderate aeration was given initially as the air bubbles started attaching to the gelatinous membranes. The airstone was removed and only slight bubbling near the surface was allowed to give water movement. By the second evening, the gelatinous matrix began to disintegrate. Microscopic analysis of the eggs found them to be undivided/unfertilized and decaying.

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