Derek Kraft

PhD Student
PI: Brian Bowen
Graduate program: Marine Biology

In general, I’m interested in preservation of marine species, specifically our pelagic shark species. Currently over fishing possess the biggest threat to these shark species; not only by reducing their prey items, but also by targeting them in shark fisheries or accidental catch in large scale fisheries such as tuna, sword fish, and bill fisheries. Silky sharks (Carcharhinus falciformis) account for over 90% of the shark by catch in the tuna fishing industry and the second most abundant shark in the mostly illegal and unreported shark finning industry. Using tissue samples collected by scientific observers aboard commercial fishing vessels, I am outlining the global genetic stock structure of the Silky shark. By looking at the genetic variation among individuals collected at different geographic locations, we can examine global connectivity, and begin to outline genetic stocks of Silky sharks. This will allow managers to make decisions not only for the species as a whole but on a stock-by-stock basis. Additionally, genetic differences between stocks will be used as a baseline for forensic identification of Silky shark fins from Hong Kong fish markets and identify their place of origin. The goal is to be able to more accurately account for Silky shark harvest around the globe and gain a better understanding of this illegal and unreported fishery.

When I’m not working on my global shark genetics project, I’m often assisting the ToBo Lab Fish Flow project, under PhD candidate Richard Coleman. Together we have collected reef fish samples from around the main Hawaiian Islands in an attempt to link spawning sites to recruitment sites for culturally important reef fish species. Essentially, we are using genetics to track reef fish from their spawning location to their settling location and seeing how far they disperse in between.  This will highlight important reef areas for spawning fish populations as well as important recruitment areas. The goal is to inform local and state managers what areas of our reefs are vital to protect to keep these important reef fish habitats intact.

As a free diver, kite surfer, and enthusiast of ocean recreation, the preservation of our marine environment is of critical importance to me. Along with research, I enjoy engaging with the community at various outreach events and believe that through communicating science we can improve the health of our oceans.