Abstract: Areal population density and detailed behavior of fish schools and their interaction are continuously monitored over continental-shelf-scale areas spanning thousands of square kilometers by ocean acoustic-waveguide remote sensing. In some embodiments, the capacity of certain geophysical environments, such as contininental shelves, islands, etc. to behave as acoustic waveguides is utilized; sound propagates over long ranges via trapped modes that suffer only cylindrical spreading loss, rather than the spherical loss suffered in conventional sonar approaches.

Abstract: A comfortable, quiet, and safe, lightweight seat which is designed for hunters, birdwatchers, hikers, and tourists to be used with any upright object such as a tree, column, or pole. The soft, flexible, sling-type seat is set up in one motion by means of a spring-braced clip and requires no adjustments since the seat automatically levels itself and automatically tightens its support around the upright object by means of a readily sliding suspending cord, and is easily tilted to any position by the user due to its balanced fulcrums. When not in use it can be neatly rolled up and placed in pocket, knapsack, or handbag.