The words "fish weir" mentioned in this chapter are defined to be a fixed structure erected and maintained during part of each fishing season in the tidewater, constructed of at least 25 spiling or stakes fastened together by binders, surrounded by brush, lath racks or netting, forming the catch pound into which fish are led or guided by one or more fixed leaders constructed of spiling or stakes not more than 20 feet apart and at least 100 feet long, fastened together by binders surrounded by lath racks, brush or netting and from which catch pound they cannot readily escape.