Is there any marine life that is spelled with the letter I?

Note that the letter part of the callsign is not the company's own letter (B vs F in the above example) - indeed, the letter designations are randomly assigned using BATCO sheets, or appear on CEI's (communication electronic instruction), and change along with the BATCO codes every 24 hours. This, together with frequency changes and voice procedure aimed at making every unit sound the same, introduces a degree of protection against simple traffic analysis and eavesdropping.