Owner means, with respect to any vessel:
(1) Any person who owns that vessel in whole or part (whether or not the vessel is leased or chartered);
(2) Any charterer of the vessel, whether bareboat, time, or voyage;
(3) Any person who acts in the capacity of a charterer, including but not limited to parties to a management agreement, operating agreement, or any similar agreement that bestows control over the destination, function, or operation of the vessel; or
(4) Any agent designated as such by a person described in this definition.
50 CFR § 300.2
In addition to the definitions in each act, agreement, convention, or treaty specified in subparts B through K of this part, the terms used in this part have the following meanings: