Abstract: Apparatuses and systems suitable for separating aquatic animals, preferably large marine animals, from a fishing line, wire, and/or hook are disclosed herein. In an embodiment, the apparatus includes a base, which is affixable to an extender, having a return aperture and seat for receiving one or more blades to form a cutting edge along the return aperture; a cover rotatably fastened to the base; a locking point to affix the base and the cover; wherein the apparatus is configurable such that, if one or more straight-edge blades is inserted into the seat, no blade tip extends beyond a perimeter of the base and the cover. Also described are systems incorporating the apparatuses elsewhere described, further possessing an extender and one or more blades. Further, described herein are methods of using any of the apparatuses and/or systems elsewhere described to separate a marine animal from a line or hook.