Six of the seven species of ray which can be found in the Dutch waters of the North Sea declined substantially in number in the period 1945-2000. One species - the skate - even seems to have disappeared completely.
The starry ray, on the other hand, has increased in number. This is a small species, which is sexually mature at the relatively young age of four to six years. Other species are only able to reproduce at ages of between eight to eleven years.
Lodewijk van Duuren and Adriaan Gmelig Meijling