Community and genetic patterns of mesophotic fishes

Mesophotic environments, occurring between 40-150m, are too deep to study on open circuit SCUBA and too shallow to invest money to study with ROVs. Thus, this environment remains a largely unexplored region of the marine realm. I am interested in the distribution of fish assemblage between shallow and mesophotic environments and the mechanisms that influence these patterns.

Additionally, mesophotic environments are thought to act as a refuge during glacial cycles where sea level decreases and 92% of the current shallow habitat disappears causing shallow species to move into deeper environments. These environments may act as a refuge against disturbances that occur in shallow habitat and therefore becoming a source populations to seed and repopulate shallow populations. Or shallow species may be unable to adapt in the naive habitat or compete with species that are specialized in the environment that they must immigrate to. To answer this question, I am interested in understanding the degree of connectivity for intraspecific fish populations across a vertical gradient, extending from shallow habitat to mesophotic environments. 

My CCR training has has proven to be a value skill which has allowed me the unique opportunity to personally explore mesophotic ecosystems. To date, my deepest dive is 330 feet (~100 meters) and my longest continuous submerged dive has been more than 4.5 hours. Many of the species I encounter at these depths are unknown to science and despite the steady increase in research related to this environment, the mesophotic environment remains largely understudied. 

I am a member of the Bottomline Projects, an NGO comprised of a team of explorers, scientists, and technical divers from around the globe who share a passion for exploring and documenting the underwater realm.

Photo: Conducting fish surveys at mesophotic depths (250') at Pohnpei, Federated States of Micronesia. Diving on closed-circuit rebreathers lets us dive to deeper depths and stay underwater for up to 4 hours or more has allows us to begin exploring mesophotic ecosystems (150-500'). These areas are too deep for SCUBA and too shallow for ROV's, thus we are pioneers in unexplored habitat. This is exhibited by new species of marine life being discovered on almost every dive that we do to mesophotic depths. Photo credit: Robert Whitton