<Li> Gross Production efficiency is the assimilation efficiency multiplied by the net production efficiency, which is equivalent to the amount of consumer production divided by amount of ingestion (P n / I n (\ displaystyle P_ (n) / I_ (n))) </Li> <Li> Ecological efficiency is the exploitation efficiency multiplied by the assimilation efficiency multiplied by the net production efficiency, which is equivalent to the amount of consumer production divided by the amount of prey production (P n / P n − 1 (\ displaystyle P_ (n) / P_ (n - 1))) </Li> <P> Theoretically, it is easy to calculate ecological efficiency using the mathematical relationships above . It is often difficult, however, to obtain accurate measurements of the values involved in the calculation . Assessing ingestion, for example, requires knowledge of the gross amount of food consumed in an ecosystem as well as its caloric content . Such a measurement is rarely better than an educated estimate, particularly with relation to ecosystems that are largely inaccessible to ecologists and tools of measurement . The ecological efficiency of an ecosystem is as a result often no better than an approximation . On the other hand, an approximation may be enough for most ecosystems, where it is important not to get an exact measure of efficiency, but rather a general idea of how energy is moving through its trophic levels . </P> <P> In agricultural environments, maximizing energy transfer from producer (food) to consumer (livestock) can yield economic benefits . A sub-field of agricultural science has emerged that explores methods of monitoring and improving ecological and related efficiencies . </P>

An ecological efficiency of 10 in a marine ecosystem means that