  For bifurcation analysis, we study the positive solution set for a semilinear
elliptic equation of the logistic type, equipped with a sublinear boundary
condition modeling coastal fishery harvesting. This work is a continuation of
the author's previous studies, where certain results were obtained in a non
resonant case, including the existence, uniqueness, multiplicity, and strong
positivity for positive solutions. In this paper, we consider the delicate
resonant case and develop a sort of non standard bifurcation technique at zero
to evaluate the positive solution set depending on a parameter. The nonlinear
boundary condition is not right-differentiable at zero.
