  We introduce a mechanism of stable spatiotemporal soliton formation in a
multimode fiber laser. This is based on spatially graded dissipation, leading
to distributed Kerr-lens mode-locking. Our analysis involves solutions of a
generalized dissipative Gross-Pitaevskii equation. This equation has a broad
range of applications in nonlinear physics, including nonlinear optics,
spatiotemporal patterns formation, plasma dynamics, and Bose-Einstein
condensates. We demonstrate that careful control of dissipative and
non-dissipative physical mechanisms results in the self-emergence of stable
(2+1)-dimensional dissipative solitons. Achieving such a regime does not
require the presence of any additional dissipative nonlinearities, such a
mode-locker in a laser, or inelastic scattering in a Bose-Einstein condensate.
Our method allows for stable energy (or "mass") harvesting by coherent
localized structures, such as ultrashort laser pulses or Bose-Einstein
condensates.
