New Publication: Shifting reef fish assemblages along a depth gradient in Pohnpei, Micronesia

Check out our new paper characterizing shallow and mesophotic reef asssemblages in Pohnpei, Micronesia [pdf]


Mesophotic coral ecosystems (MCEs) continue to be understudied, especially in island locations spread across the Indo-Pacific Ocean. Pohnpei is the largest island in the Federated States of Micronesia, with a well-developed barrier reef, and steep slopes that descend to more than 1000 m. Here we conducted visual surveys along a depth gradient of 0 to 60 m in addition to video surveys that extend to 130 m, with 72 belt transects and 12 roving surveys using closed-circuit rebreathers, to test for changes in reef fish composition from shallow to mesophotic depths. We observed 304 fish species across 47 families with the majority confined to shallow habitat. Taxonomic and trophic positions at 30 m showed similar compositions when compared against all other depths. However, assemblages were comprised of a distinct shallow (<30 m) and deep (>30m) group, suggesting 30 m as a transition zone between these communities. Shallow specialists had a high probability of being herbivores and deep specialists had a higher probability of being planktivores. Acanthuridae (surgeonfishes), Holocentridae (soldierfishes), and Labridae (wrasses) were associated primarily with shallow habitat, while Pomacentridae (damselfishes) and Serranidae (groupers) were associated with deep habitat. Four species may indicate Central Pacific mesophotic habitat: Chromis circumaurea, Luzonichthys seaver, Odontanthias borbonius, and an undescribed slopefish (Symphysanodon sp.). This study supports the 30-m depth profile as a transition zone between shallow and mesophotic ecosystems (consistent with accepted definitions of MCEs), with evidence of multiple transition zones below 30 m. Disturbances restricted to either region are not likely to immediately impact the other and both ecosystems should be considered separately in management of reefs near human population centers.

Featured in the journal of Oceanography

I have a short blurb in the newest issue of Oceanography.  This entire issue is a special issue dedicated to discussing graduate education in the ocean sciences. [pdf]

Check out page 88!

NSF’s Graduate Student Support Programs: An Overview and Reflections from a Former Fellow
Cook, S.B. 2016. NSF’s Graduate Student Support Programs: An overview and reflections from a former fellow. Oceanography 29(1): 86–89.


NEW PUBLICATION: Phylogeography of the Regal Angelfish

NEW PUBLICATION: Four distinct lineages recovered from phylogeographic analysis of a wide-ranging angelfish

My recent paper titled "Regal phylogeography: Range-wide survey of the marine angelfish Pygoplites diacanthus reveals evolutionary partitions between the Red Sea, Indian Ocean, and Pacific Ocean" was published today. Here is a link for a free download (expires June 14):

A download is also available on my CV page.

Abudefduf featured in Hakai Magazine

Abudefduf featured in Hakai Magazine

The Indo-Pacific sergeant fish hides in the reefs of warm coastal waters from Japan to New Zealand to the Persian Gulf. The small tropical fish spends most of its life eating plankton and rarely ventures far from shore. Yet, one day in 1991, an Indo-Pacific sergeant showed up in Hawaii—far, far from home.