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Lionfish

Posted on December 10, 2010 at 10:45 AM Comments comments (0)

Lionfish Pterois volitans - Things you should know.

Size: There are many types of lionfish that vary in size. Normally they can be between

 30 cm to 35 cm (12 inches) long. In the Caribbean where lionfish are not indigenous, they grow to up to 55 cm.

Warning: The venom of the lionfish, delivered via an array of up to 18 needle-like dorsal fins, is purely defensive. It relies on camouflage and lightning-fast reflexes to capture prey, mainly fish and shrimp. A sting from a lionfish is extremely painful to humans and can cause nausea and breathing difficulties, but is rarely fatal.

Lionfish, also called turkey fish, dragon fish and scorpion fish, are native to the reefs and rocky crevices of the Indo-Pacific, although they've found their way to warm ocean habitats worldwide.

First Aid: A common treatment is soaking the afflicted area in hot water, as very few hospitals carry specific treatments. However, immediate emergency medical treatment is still advised, as some people are more susceptible to the venom than others.

 

Gender: When lionfish are ready to reproduce, the physical differences between the sexes become more obvious. Males turn darker and are more uniformly colored (their stripes are not as apparent). Females with ripening eggs become paler. Their belly, pharyngeal region, and mouth become silvery white. Such females are easy for the males to spot in the darkness.

 

Reproduction: Courtship begins just before dark and is always initiated by the males. After the male searches out a female, he rests next to her on the substrate and looks toward the water surface while propping himself up on his ventral fins. He then proceeds to circle the female. After circling several times, the male then ascends to the water surface with the female following behind. While ascending the female will tremble her pectoral fins. The couple may descend and ascend several times before spawning. On the final ascent the couple will swim around just under the surface of the water. The female will then release her spawn. These spawn are comprised of two hollow mucus tubes that float just below the surface upon release. After approximately 15 minutes, these tubes fill up with seawater and become oval balls 2 to 5 cm in diameter. Within these mucosal balls lie 1-2 layers of individual eggs. The number of eggs per ball varies from 2,000 to 15,000. As the female spawn are released, the male releases his sperm, which penetrate the mucosal balls and fertilize the eggs inside.

Twelve hours after fertilization the embryo begins to form. Only 18 hours after fertilization, the head and eyes become moderately developed. Eventually, invading microbes deteriorate the mucus walls and 36 hours after fertilization, the larvae hatch. Four days after conception, the larvae are already good swimmers and are able to begin feeding on small ciliates (Fishelson, 1975).


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