Chimaera Reproduction

Chimaera are similar to sharks in some forms in that they employ claspers for internal fertilisation of females. It is known that chimaeras are oviparous in their reproductive biology. The females produce large yolky eggs, pale yellow in colour and similar in size to their close relatives the sharks. The embryos develop inside eggs that are retained within the mother’s body and are encased individually in a tough leathery case. Once ready the eggs are deposited directly upon the seafloor until they are ready to hatch. Females have been observed to spawn two eggs at a time, one from each oviduct. As with sharks and rays, the shape and size of the egg capsule is characteristic to each chimaera family. However, chimaera display some differences to sharks in that they possess additional retractable sexual appendages on the forehead and in front of the pelvic fins for reproductive benefits.

It is thought that chimaera may be reproductively active throughout the year, without a defined or apparent egg laying period. The Rabbitfish (Chimaera monstrosa) is one of the better known species and has been most documented in terms of reproduction and sexual segregation, a behavioural mechanism whereby the sexes sometimes spend time apart from each other. This particular species migrates inshore during spring and summer months to lay egg capsules at depths below 100m, with a defined reproductive season of 6 – 7 months with a peak in activity in the northern winter. It is thought that this species tends to aggregate together in groups and may be segregated by size and age of maturity. Similar patterns have also been seen within the Spotted Ratfish (Hydrolagus colliei), which has been shown to have a defined reproductive season.

There are still major gaps within our knowledge of biology and behaviour of many chimaera species. Some species have no information available at all on reproduction and age of maturity, again mainly due to their deep sea habitat and the difficulty of studying these species.

Chimaera do share similar life history characteristics to that of shark and ray species. They are typically described as an unproductive species attaining sexual maturity at a late age usually between 11 and 14 years depending on species. They are also extremely long lived, between 25 and 30 years, and produce few young.

Related Links:

About Chimaera

Chimaera Taxonomy

Chimaera Diet

Chimaera Distribution

Chimaera Conservation