Conversion Confusion -Does Annual P/B Equal Cohort P/B for Multi yeared Organisms? A Cautionary Tale for Ecotoxicology Studies

The ratio of secondary production to biomass (P/B), of ten referred to as the turnover rate and expressed on both a yearly and lifespan basis for aquatic macroinvertebrates and insects, has been championed as a measure of ecosystem function and as a means in which to gauge environmental disturbance. A review of the literature indicates, however, that opinions vary and enough confusion exists in terms of the methodology used to derive this metric as to question its uncritical adoption in investigations of ecotoxicology and stress ecology.