Hairy sea hares

There were hairy sea hares on some patches of Cyrene Reef seen on Friday and today. At first glance they may appear to be the same, but a closer look suggests that there are two kinds of hairy sea hares out there today.
One kind is really 'hairy' with long projections all over. This is Bursatella leachii that is sometimes seen in huge numbers on Chek Jawa and our other northern shores. They are seasonal and shortly after an explosion of numbers, they are often not seen again for many months.Like other sea hares, it has two pairs of tentacles, oral tentacles (in front of the mouth) and rhinophores on top of the head. But these tentacles have hairy projections and are thus hard to distinguish from the rest of its hairy body.Bursatella leachii has blue spots on its body that sometimes form 'eyes' (with a dark centre) and patterns of small dots. The 'hairs' tend to be large, often flat and rather long.

The other hairy sea hare has shorter 'hair'.Its oral tentacles and rhinophores are more obvious as the hairy projections on them are not so long.Its body pattern comprises tiny blue dots and small spots and fine lines. The 'hairs' tend to be short and conical.This sea hare is possibly Stylocheilus sp. I have not seen it as often as Bursatella leachii. It too seems rather seasonal.

Both sea hares produce a red dye when they are stressed. They are well camouflaged among seaweeds and seagrasses, so please watch your step. If you see a red dye, it means you might have injured one.