Small-spotted catshark (lesser spotted dogfish)

How it lives

It lays eggs. Each egg is in a leathery case, about 5 to 7 cm (2 to 2.8 in) long, with curly tendrils that cling to seaweed. Empty cases wash up on beaches and are known as mermaid's purses. Eggs are laid from about January to June and take about 5 to 11 months to hatch, depending on water temperature. Hatchlings are 8 to 10 cm (3 to 4 in) long. It reaches maturity at about 36 to 49 cm (14 to 19 in) in one source, while FishBase gives 50 cm (range 35 to 64 cm). FishBase lists a maximum age of 12 years, and a longer record of at least 14 years has been reported.

Where it goes

The sources I read do not describe long migrations. It rests on the seabed by day and hunts at night. Males rest on the bottom and females shelter in shallow caves in daylight. Depth is usually 10 to 780 m, most often about 80 to 100 m in the north-east Atlantic.

We only draw a journey on the map when scientists have tracked it or clearly documented it. For this animal we have not found one yet.

Populations

Least Concern globally (IUCN, assessed 2020). The IUCN assessment, as quoted on Wikipedia, found no evidence that the global population has declined significantly. It is among the most common sharks around Britain and Ireland, and numbers in Scottish waters are described as unknown. It is mostly a fishing bycatch and is often discarded, and survival after release can be high. Norway also lists it as Least Concern. I did not find counts by country.