A Coupled Asymmetrical Multiple Opening Closing Net with Environmental Sampling System

Abstract

Recruitment levels of fishes are potentially related to the abundance of larval fishes and their food source. A system that could allow for the concurrent investigation of fine-scale distribution of fish larvae and their potential prey could add significantly to the understanding of the early life history of marine fishes. A coupled Multiple Opening Closing Net and Environmental Sensing System (MOCNESS) that combines two sub-systems (1 m2 and 4 m2 net sets) working in synchronization was designed to answer these questions. The mesh size was different on each set of nets allowing the collection of a broad size range of organisms while optimizing the catch of larger fish larvae and eliminating unnecessary large samples of zooplankton. Moreover, the system eliminated the need to deploy separate MOCNESS using different mesh sizes, thus reducing ship time costs, and avoiding any aliasing associated with trying to sample the same water mass with separate nets fished sequentially. The system has been used at sea under varying weather conditions onboard the R/V F. G. Walton Smith and sampled adequately.