Fig 6. A progressive “ecological” tax for the seaweed (kelp) fishery is described.
The yield curve (Y) is a quadratic curve of effort (E) with a single maximum at EMSY which is reached at biomass = K/2 (K = carrying capacity) of the classic differential logistic equation. A stable relative maximum for GFF lie in the middle left of the yield curve, ensuring different intensities of harvest The progressive “ecological” tax is based on the distance to EMSY (or K/2) (cero means without harvest and EMSY equals maximum harvest). Points A and B represent arbitrarily different levels of taxing rates, increasing the total operational cost. For more details see text.