The percentage of fish dying in one year due to both fishing and natural causes. A saccular breathing organ in many arachnids containing numerous thin folds of a membrane arranged like the leaves of a book. The harvest of fish or shellfish other than the species for which the fishing gear was set.
Examples are blue crabs caught in shrimp trawls or sharks caught on a tuna longline.
Some bycatch is kept for sale. A bony or chitenous case or shell covering the back or part of the back of an animal, such as a crab. The total fish captured from an area over some period of time, including fish that are caught but released or discarded instead of being landed. Catch can be recorded in pounds or numbers. Note that catch, harvest, and landings are different terms.