(a) In general
The Secretary may conduct investigations and inspections regarding a vessel's compliance with this chapter or the Convention.

(b) Violations; subpoenas

(1) In general
In any investigation under this section, the Secretary may issue a subpoena to require the attendance of a witness or the production of documents or other evidence if—

(A) before the issuance of the subpoena, the Secretary requests a determination by the Attorney General of the United States as to whether the subpoena will interfere with a criminal investigation; and

(B) the Attorney General—

(i) determines that the subpoena will not interfere with a criminal investigation; or

(ii) fails to make a determination under clause (i) before the date that is 30 days after the date on which the Secretary makes a request under subparagraph (A).

(2) Enforcement
In the case of refusal to obey a subpoena issued to any person under this subsection, the Secretary may request the Attorney General to invoke the aid of the appropriate district court of the United States to compel compliance.

(c) Further action
On completion of an investigation, the Secretary may take whatever further action the Secretary considers appropriate under the Convention or this chapter.

(d) Cooperation
The Secretary may cooperate with other parties to the Convention in the detection of violations and in enforcement of the Convention. Nothing in this section affects or alters requirements under any other laws.