The author was fortunate enough to come across a pair of mating Raja epaulette
sharks on a night dive.
The male epaulette shark begins wagging its tail, possibly to facilitate sperm transfer. This causes the tail section of the pair to adopt a head stand.
When it comes to epaulette sex, all sharks practice internal fertilization. The males have a pair of appendages on the inner edge of the pelvic fins known as claspers. These are used to transfer sperm into the females cloaca and are conspicuous sexual characteristics that can be used to tell the gender of even the youngest shark or ray. When juvenile, the claspers are short, soft and highly flexible, but as an adolescent shark approaches maturity, the claspers grow and become more rigid. In a fully mature male shark, they are stiffened by internal cartilage and can be rotated forward around their base. When they mate, the male epaulette shark swings a clasper into a forward facing position and inserts it into the cloaca of the female.
Courtship and copulation is often a rather rough affair in epaulette sharks. The male will initially nip and grasp the female in his jaws. When he eventually is able to grasp on the female’s pectoral fin, the male shark will swing the pelvic region under hers’ so mating can occur. (I have included photos of mating Raja epaulette sharks [Hemiscyllium freycineti] that I ran across in shallow water on a reef in the Raja Ampat Islands.) These pugnacious mating tactics can cause problems in the aquarium. An amorous male may cause problems with female tank mate if he bites and chases her incessantly. For this reason, it is good idea to have another tank in which to place a female after mating has occurred or if a male becomes too rough during courtship. Remember, a female that is not sexually receptive can get away from a male in the wild but not in the confines of even the largest home aquarium.
The male epaulette swims off with the spur of the clasper flared out
after its recent use - they most always only use a single clasper
After insemination occurs, they female will lay an egg that is surrounded by a leather case with tufts of filaments that adhere to reef structure. The young shark develops in this encasement for about 80 days (the incubation time is temperature dependent). The fully developed epaulette shark pops out of the egg case being an almost exact anatomical replica of the adult shark ( the color differs between juveniles and adults).
It is possible that these sharks will reproduce in captivity. In fact, more and more people in the US and abroad are breeding epaulette shark species in their homes and captive raised individuals are starting to show-up in in the pet fish trade with greater regularity. This is a great thing for wild shark stocks and potential shark-keepers alike!
© Scott W. Michael- Reef Tectonics
Reef Tectonics Aquarium Maintenance and Design - Lincoln, Omaha, Des Moines, Kansas City
Post a Comment