Are there any PhD distance possibilities for such areas as animal science or aquaculture out there that anyone is aware of, especially in the U.S.?
In the US, if you are willing to consider short-residency programs, I may suggest Union Institute and University (Interdisciplinary Arts ans Science) and Nova Southeastern University (School of Oceanography and Marine Biology). Based on the contents of Nova's Oceanography FAQs page, many graduate courses can be completed online but students must meet the programs' residency requirements to graduate. Also, it appears that students can complete several doctoral courses by directed independent study. Besides those two that I have mentioned, there are also several Australian options. You may check them out at Jonnie's Distance Learning Page. Ike Okonkwo