Sponges are an important part of the wreck community as they can be abundant, have many species present and create further structural complexity beyond the wreck itself. However, identifying sponges underwater or from images can be challenging due to the diversity of species, and that within a single species there are often variable growth forms and colouration. Here we present some of the prominent species observed on the wrecks surveyed in the project.
Chimney sponge Polymastia penicillus
The chimney sponge has vertical projections originating from a silt covered base. The colour is pale yellow to orange, with some of the projections being larger and terminating in a large hole where water is expelled, called the osculum. This image is from the horizontally orientated hull side of the SS Derbent wreck.
Mermaid’s glove horny sponge Haliclona oculata
This distinctive branching sponge species has been seen on several First World War wrecks in Welsh waters. It can be yellow to beige in colour and can be distinguished from other branching sponges by the presences of holes, called oscula, on and along the branches.
Fleshy horny sponge Suberites carnosus
This sponge is found in the form of irregular balls or blobs attached to the wreck structure. It is yellow in colour with a large hole, or sometimes several, called oscula in the upper surface. It can tolerate silty conditions, as seen on the wreck off the Cartagena in the image.
Shredded carrot sponge Amphilectus fucorum
This sponge can appear, as seen in this image from the SS Derbent wreck, as mounds with large oscula or in a tasselled form that resembles shredded carrots. It is incrusting in habit and can be pale to bright orange.