The anemone is a truly unique and amazing animal, that many of us fail to acknowledge as an animal. Anemones represent an important part of the reef diversity and abundance of life found there. As a home and refuge for a myriad of clownfish and certain damselfish not to mention the invertebrates that form an integral niche within or on an anemone and use as a defense mechanism such as anemone and pom pom crabs and sexy shrimp that have a commensal relationship with anemones. Because of the importance and reliance on anemones by numerous life forms, anemones play an integral part of the reef chemistry and their ability to reproduce remains a very crucial development. Fortunately anemones are able to reproduce either sexually or asexually and are able to do this numerous ways, which you will soon see.
The various ways in which an anemone can reproduce is evident not only among species but within the species as well. Sexual reproduction is one way in which an anemone can carry on the species, as anemones are either hermaphrodites(individuals produce both male and female gametes) or dioecious( individual either carries male or female gametes). Anemones carry out sexual reproduction during various times of the year based on a few key underlying factors. Species, location in the wild, salinity and temperature of the water and spawning of other corals and Tridacna Clams all can have an effect on the time and frequency of reproduction. In terms of sexual reproduction anemones can either produce larvae that is “brooded” and develop inside the mother anemone till a daughter clone, complete with tentacles, ripens and is released into the water column. Then their are others that release male gametes initially into the water in hopes that a female anemone will release female gametes to fertilize the sperm cells. The sperm can be released into the water either through the mouth of the anemone, tentacles or pores in the column. Sometimes the female anemone will not release female gametes into the water but will wait for the sperm cells to enter the gastric cavity of the female anemone to fertilize the female eggs.
Asexual reproduction in anemones is often performed through a form of vegetative propagation, where sex cells are not produced nor do they have any profound impact on the creation of a daughter anemone similar to the mother. Asexual reproduction is a more efficient means of creating a new anemone hence is a more effective way of ensuring that an anemone will survive rather than by starting off as a larvae being carried off downstream in the current in hopes of settling to attach and grow without being eaten first. The various ways of asexual reproduction or growth will be described below and can be encountered in any captive environment or in the wild though some forms of asexual reproduction are more common than others.
Pedal laceration can be best explained as the ability of a mother anemone to sever a small piece of its pedal(foot) which will then form totally exact replica of the mother anemone. This is also very common in certain species of octocoral(soft corals) such as Xenia.
Budding is frequently seen in coralimorpharia and certain scleractinians such as Fungiidae and Faviidae. This happens when the sphincter located at the base of the tentacle constricts causing the tentacle to shed and break off at the base of the tentacle at the sphincter location. This detached tentacle will then produce a new daughter anemone. This is not a very common occurrence in anemones and seems to be more a direct action of anemones and their response to riding predatory nudibranches from killing the anemone.
Transverse fission is another common site in anemones where the mother will produce a ring of small tentacles at the column of the mother. The tentacles will break off just below the tentacle area and form a new separate anemone eventually. One very interesting note on this type of asexual reproduction is the fact that if a predator eats a piece of the anemone, often times the broken off part will produce a totally separate anemone if it doesn’t get eaten, plus the broken off part of the mother anemone usually regenerates the piece that has been removed as a direct result of predation.
Longitudinal fission is a case where the mother anemone divides through the oral disc and pharynx, forming two or more daughter polyps complete with a section of the mother’s tentacles, eventually leading to the growth of fully functioning baby anemones.
Often times, people try to classify the age of an anemone based on its size similar to a tree and the rings that are produced each year of a trees life. This is not the case with anemones, as the ability of anemones to break off a piece of themselves whether large or small without having to start as a fertilization process where the male and female gametes meet thus producing a small larvae. This asexual means of reproduction affords anemones the ability to grow faster by skipping steps in the fertilization and growth processes. Also it seems that the larger the mother anemone is the frequency and chances of asexual reproduction become drastically reduced especially in specific species of anemones.
So there you have it! Anemones are truly amazing animals(not plants or flowers!!!) that have evolved up till now through the many various methods of reproduction. It is an amazing site to see an anemone going through the transformation and reproduction state of creating a totally separate and independent daughter anemone through one of these processes, that enable the species to compete and evolve in the wild and in our reef aquariums as well.
