by-catch vs bycatch

by-catch and bycatch both are nouns.

Word	Noun	Adjective	Verb	Adverb
by-catch	Yes	No	No	No
bycatch	Yes	No	No	No

As nouns, by-catch and bycatch are synonyms defined as:

by-catch and bycatch: unwanted marine creatures that are caught in the nets while fishing for another species

by-catch (noun)	bycatch (noun)
unwanted marine creatures that are caught in the nets while fishing for another species	unwanted marine creatures that are caught in the nets while fishing for another species