Fish LC50 definition

Fish LC50 means the concentration that will kill fifty percent or more of the exposed fish in a specified time period. For book des- ignation, LC50 data must be derived from an exposure period greater than or equal to twenty-four hours. A hierarchy of species LC50 data should be used that includes (in decreasing order of preference) sal- monids, fathead minnows (Pimephales promelas), and other fish species. For the ninety-six-hour static acute fish toxicity test, described in WAC 173-303-110 (3)(b)(i), coho salmon (Oncorhynchus kisutch), rainbow trout (Oncorhynchus mykiss), or brook trout (Salvelinus fontinalis) must be used.
Fish LC50 means the concentration that will kill fifty percent or more of the exposed fish in a specified time period. For book des- ignation, LC50 data must be derived from an exposure period greater