Cape Marshall (Puerto Egas) lies on the eastern side of Isabela island. You dive where a huge lava stream from the Wolf volcano stopped flowing into the ocean. The lava breaks off abruptly and forms a very steep slope with boulders and lava ridges. Cover is sparsely with some black corals. Dependig on the prevalent current you dive along either from north to south or vice versa.
This is a good place for mantas, mobula rays and eagle rays but also for the occasional shark, yellowfin tuna and sealion. We saw several huge mantas close by - one of them black on the top as well as on the belly - but the most impressive sight was the school of mobula, probably at least 50 animals, that we met several times. As we swam out into the blue, they were suddenly all around us, with quick flips they sped past us and the whole school engulfed us, mobulas in front, above, behind and on all sides! They stayed around, formed a more compact group again and let us swim along for a while. A eagle ray which also joined us only got a glimpse from us, we were so entranced from the mobula rays!