Abstract: A methodology to reconstruct vertical profiles of the absorption and scattering coefficients in offshore ocean waters is presented, using {\it in-situ} radiance measurements in several depths and single wavelength. A multi-region approach is employed and azimuthal symmetry is assumed. The inverse problem is formulated as an optimization problem and iteratively solved using the radiative transfer equation as direct model. An objective function is given by the square difference between computed and experimental radiances at every iteration. In the current work, bio-optical models are employed to correlate the Chlorophyll concentration to these coefficients. At every iteration, the inverse solver generates a candidate solution that is a set of discrete Chlorophyll concentration values for each region. The radiative transfer equation is solved using the Laplace transform discrete ordinate (LTSN) method. This objective function is minimized by an Ant Colony System (ACS) code. A recent regularization scheme pre-selects candidate solutions based on their smoothness, in addition to the classical Tikhonov regularization. Finally, a parallel implementation of the Ant Colony System is used and executed in a distributed memory machine. Test results show the suitability of the proposed method.