The biological effects component of the natural resource damage assessment model system

The natural resource damage assessment model for coastal and marine environments (NRDAM/CME) provides a methodology for assessing natural resource damages following spills of toxic substances. The NRDAM/CME contains physical fates, biological effects and economic damages components. The biological effects submodel is described herein.

The biological effects submodel estimates direct mortality resulting from toxic concentrations of the spilled substance and lost production of organisms in the marine food web resulting from loss of food resources. Mortality and reduced productivity, are functions of concentration, time of exposure and temperature. Long-term losses include lost recruitment of larvae and juveniles into the adult population and lost future growth of adults. Using accepted fisheries models, catch losses at the time of the spill and into the future are estimated and passed to the economic damages submodel for valuation. For birds and mammals, both viewing and hunting losses are similarly calculated, as appropriate.