Quirks Model (K. Huebert and M. Peck)
Quirks is a generic, individual-based model currently parameterized to simulate foraging behavior and growth of young exogenously feeding larvae of four species: 5.5-mm European anchovy (Engraulis encrasicolus), 7-mm Atlantic cod (Gadus morhua), 13-mm Atlantic herring (Clupea harengus), and 7-mm European sprat (Sprattus sprattus). In Quirks, different species are defined by a list of traits, and the larval foraging and growth are modeled following one unified set of mechanistic rules, including the optimal foraging routine. Moreover, Quirks model includes a routine to build a normalized biomass size-spectra (NBSS) of zooplankton based on the total zooplankton biomass and NBSS slope.
- Huebert, Klaus B., and Myron A. Peck. “A day in the life of fish larvae: modeling foraging and growth using quirks.” PLoS One 9.6 (2014): e98205.
The original function used to build the zooplankton normalized biomass size-spectra contains following code:
prey.int <- function(slope,lo=prey.lo,hi=prey.hi)# preyfield integral (µg)
{ slope <- slope+(slope+1==0)*1e-6# prevents division by zero
prey.DM(hi)^(slope+1)/(slope+1)-prey.DM(lo)^(slope+1)/(slope+1)}
However, the correct mathematical solution is as follows:
prey.int <- function(slope,lo=prey.lo,hi=prey.hi)# preyfield integral (µg)
{ if slope==-1
(log(prey.DM(hi)) - log(prey.DM(lo)));
else
prey.DM(hi)^(slope+1)/(slope+1)-prey.DM(lo)^(slope+1)/(slope+1)
else
}