Life history diversity & the portfolio effect
Life history diversity (biocomplexity) can produce a ‘portfolio effect’, where variability in the aggregate stock complex is lower than that of its individual components. I am interested understanding how portfolio effects impact resilience at different scales (e.g. among species, runs, populations, life stages), and trying to use this information to improve management and conservation strategies for commercially important and endangered fishes .
In these papers we used rotary screw trap data to quantify the "expression" of migratory phenotypes (size, abundance and timing of juveniles outmigrating from the natal stream), and otolith isotope reconstructions to estimate their relative survival. This type of analysis is difficult to carry out using applied tags because many of the outmigrants are too small to tag and/or have such low survival rates that it becomes exorbitantly expensive.