The genital organs of coral are located inside the polyps and they have different genders in the sense that there are both male and female colonies. In some cases we also noted the presence of hermaphrodite colonies, created by the fusion of two colonies.
The maturing of the male reproductive cells occurs after one year while for females 2 years are required.
How does reproduction take place? By fertilisation of by larval reproduction.
Fertilisation: following emission from the male polyp, the spermatozoa navigate looking for a female polyp to fertilise.
The mechanism of attraction is still a mystery.
Fertilisation then takes place inside the female polyp.
The young larva, called planula, develops in approximately 20/30 days before exiting into the open sea.
This process usually occurs during the month of June.
In the future this will involve a number of considerations – which will certainly arouse polemics – regarding the possibility of fishing before the new organisms, the planulae, are born.
Larval Reproduction: The planulae leave the mother polyp and wander through the waters looking for a hard and rocky substratum upon which to deposit. Once they find it, a new miracle takes place: the mouth with its eight tentacles positions itself to collect food, the first gastrovascular canals develop and in about twelve days, what will be the skeletal axis begins to form…the skeletal axis is the interior of the branch, the calcium carbonate skeleton, and in about 2/3 days it gradually becomes red.
What had originally been a planula begins to feed and grow, to swell like a large pimple: and this is when a second polyp appears!
From this moment on the two work to secrete, building the skeletal axis that will be fully formed in six months!
Thus from larva to larva, polyp to polyp, the coral branch grows and develops. As we can see, all the vital functions of a coral colony are in the sarcosoma, the external part of the polyp.
If all the coral of Sciacca, as noted by many, suddenly appeared without a sarcosoma, what would this mean? Indubitably and unquestionably that we are in the presence of dead coral, my friends, of which only the skeleton remains, and we don’t even really know why...
to be Continued...
[text taken with license from the author Giuseppe Rajola from the book Sciacca Mystery]
Enjoy!
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