Last year and this year, we had heaps of frogs and about 20 groups of spawn. Very little frost, have had successful spawn for 6 years previously. Within a few weeks all the spawn sank with no tadpoles. Is this a local problem in Cardiff or is it our pond, we've never cleaned it out and have lots of newts. Someone suggested the males were infertile, but why. It's been very successful before.
Presumably there aren't any fishes in the pond? I'm wondering whether the long dry February meant the water quality was poor. Just a guess. At the previous house, I know huge numbers of frogs ended up stirring all sorts up from the depths.