Fish & G. Code, § 8563

(a) Except as provided in subdivision (b), the permittee shall be aboard the vessel and shall be in possession of a valid drift gill net shark and swordfish permit when engaged in operations authorized by the permit.

(b) A permittee may have a person serve in the permittee’s place on the permittee’s vessel and engage in fishing under the permittee’s drift gill net shark and swordfish permit for not more than 15 days in a calendar year, except that a longer period may be allowed in the event of serious illness. A permittee shall notify the department’s Long Beach office of a substitution of 15 days or less per calendar year, by certified letter or telegram at least 24 hours before the commencement of the trip. Written authorization for a substitution of greater than 15 days shall be obtained from the director and shall be given only on the director’s finding that the permittee will not be available to engage in the activity due to serious illness, supported by medical evidence. An application for a substitution of greater than 15 days shall be made to the department’s headquarters office in Sacramento, and shall contain any information the director requires. A denial of the substitution may be appealed to the commission.