Meeting Abstract
Clingfish (Gobeisocidae) are small, shallow water fishes found in marine and freshwater environments. They are distinctive for having a suctorial disk on their belly made up of elements of the pectoral and pelvic girdles and fins. Work on one species, the Northern Clingfish (Gobeisox maendricus) has demonstrated the extreme tenacity of this disk on smooth and rough surfaces. Across the family this disk is variable in size and shape. There are double disks, disks with many papillae, and disks that appear small for the length of the fish. We report on the disk morphology and performance of 10 species of clingfish from New Zealand. Morphologically two groups stand out – rubble associated with relatively large disks and algae associated species with smaller disks. We tested fish on molds from six abrasive surfaces, from smooth to 120grit. The peak stress under the disk ranged from 50-100kpa. The theoretical maximum stress in our experimental design was 101kPa. It was possible to get performance data from fish as small as 70mg. Smaller fish could not stick to the roughest surfaces. The suctorial disk is a device that requires no living input. A dead fish will stick repeatedly with the same tenacity an arbitrary number of times. We made over 100 tests on one fish without degradation of attachment.
