Abstract: An apparatus has a lens assembly which has: a front region with an entrance window of the lens assembly; a window structure at the entrance window; a back region; a lens between the window structure and the back region; and a heater coupled to heat the window structure. The lens assembly includes a reflective surface. The front region is on a first side of the reflective surface. The back region is on a second side of the reflective surface. The reflective surface reflects thermal radiation generated by the heater. The reflected radiation is reflected towards the first side. Other features are also provided.

Abstract: A pneumatic plunger system for use in a commercial seine fishing vessel, comprising apparatus for expelling a mixture of forced air and water through a plurality of nozzles that are located along the keel of the vessel. The forced air and water which is ejected through the nozzles creates a wall of air bubbles extending substantially vertically and downward from the keel. Fish swimming between the net and the wall of air bubbles are startled by the air bubbles and are repelled into the net.