Tiger shrimp

I had to experiment a bit to achieve clear pictures of these tiger shrimps Gammarus tigrinus that we found yesterday in the Counter Drain in Lincolnshire. I used the light table again, but had to try and increase the shutter speed, as unlike algae they never stay completely still.

This image shows a male and female. The male is on the left, and in large you can clearly see the gills like a bunch of feathers between its legs. The smaller female is more heavily pigmented with red at the tail end, and you might just be able to make out a batch of eggs tucked behind her forelegs.

The tiger shrimp is not native to the United Kingdom and is an endemic species of the Atlantic seabord of North America, occupying coastal estuarine habitats. It was introduced to Britain in the early twentieth century, and is now quite widely distributed. This species has a long breeding season and is more fecund than the native Gammarus species. It eats plant material (including ropes and fishing nets!) but is noted as a rapacious and voracious predator on other species of Gammarus, other invertebrates and small fish.