Improvements to the 'sket bottle': A simple manual device for sampling small crustaceans from marine caves and other cryptic habitats

摘要

Dark littoral submarine caves can act as enclaves of the deep aphotic zone in shallow coastal areas, and their survey has revealed the existence of a very particular fauna of specialized and poorly known organisms among which crustaceans are particularly well represented. In these particular habitats, the use of conventional sampling techniques, such as hand nets, is often not recommended since they disturb bottom sediments causing hazardous situations to scientific divers. The use of baited traps, while technically possible, is not. always practical is such remote habitats. The present work describes a simple and inexpensive manual device that can be operated by divers ill submarine caves and other cryptic habitats to recurrently catch small motile organisms such as mysid crustaceans, caridean shrimps, or even gobiid fishes. This small suction bottle derived and improved from the original "Sket bottle" design considerably reduces the risks of disturbing the cave's bottom sediment and can be easily operated using a single hand. The described sampling device can also be easily used outside caves, in a variety of particular habitats, e.g., rubble filled bottoms, branching coral reefs, cracks, and small holes on rocky surfaces, in which small motile organisms usually escape from traditional sampling gears, e.g., fishnets and traps, or simply go unnoticed by researchers during sampling.