The percentage of energy converted into biomass by a higher trophic level over the energy of food resources available at the lower trophic level is called ecological efficiency. It is also called Lindemann’s trophic efficiency rule. $EE = \frac{\begin{array}{r}
Energy\ converted\ into\ \\
biomass\ at\ trophic\ level\
\end{array}}{\begin{array}{r}
Energy\ present\ in\ biomass\ \\
at\ lower\ trophic\ level\
\end{array}} \times 100$