Cloudy Catshark - Biology and Ecology

Biology and Ecology

The cloudy catshark feeds primarily on molluscs, followed by crustaceans and bony fishes. A predator of both this shark and its egg cases is the blotchy swell shark (Cephaloscyllium umbratile). A known parasite of this species is the myxosporidian Chloromyxum scyliorhinum. Reproduction is oviparous; adult females have a single functional ovary and two functional oviducts. As a prelude to mating, the male bites at the female's pectoral fin, side, and gill region. Once he has a grip, he wraps his body around hers and inserts one of his claspers into her cloaca. Copulation may last between 15 seconds and 4 minutes. The claspers of the male are unusual in that each has a row of around a hundred hooks running along the inner margin. These hooks likely serve to anchor the male to the female during copulation. The female is capable of storing sperm within her nidamental gland (an organ that secretes egg cases) for many months.

Females produce two mature eggs at a time, one per oviduct. The eggs are enclosed in smooth, translucent yellow, vase-shaped capsules measuring 1.9 cm (0.75 in) across and 5.5 cm (2.2 in) long. There are long tendrils at the four corners of the capsule. The eggs are laid in defined nursery areas: One such area is located at a depth of 100 m (330 ft) off Hakodate. When the embryo is 3.6 cm (1.4 in) long, it has external gills, undeveloped fins, and no pigmentation. At an embryonic length of 5.8 cm (2.3 in), the external gills have all but disappeared, and a covering of small denticles is present. By a length of 7.9 cm (3.1 in), the embryo has well-developed fins and pigmentation, and generally resembles the adult. The eggs take 15 months to hatch at 11.3 °C (52.3 °F), and 7–9 months to hatch at 14.5 °C (58.1 °F). The newly hatched shark measures 8 cm (3.1 in) long or more. Maturation size tends to increase with decreasing water temperature: Off northerly Hakodate, both sexes mature at over 38 cm (15 in) long, while some females remain immature even at 47 cm (19 in) long. By contrast, off southerly Tsushima Island both sexes mature at around 33 cm (13 in) long. The maximum lifespan is at least 12 years.