Brendan J. Runde
MS Student, Fisheries, Wildlife, and Conservation Biology
Jeffrey A. Buckel
2013 – B.S. Biology and Fisheries Science, Summa Cum Laude, Virginia Tech
Discard Mortality of Gray Triggerfish
A Gray Triggerfish that was tagged previously and recaptured on a subsequent research expedition. The intestinal prolapse is one of the most common signs of barotrauma. We are interested in learning whether fish with such injuries are likely to survive after release.
My main interests lie in marine resource conservation and the biology of charismatic ichthyofauna. My thesis project is entitled “Estimating Discard Mortality in Gray Triggerfish Using Surface and Bottom Tagging.” The target species (Gray Triggerfish) is important in the commercial and recreational fisheries of North Carolina and the U.S. south Atlantic as a whole. Triggerfish, like other reef fish that can inhabit depths of >100 ft, often suffer pressure-related trauma (called barotrauma) when they are brought to the surface by fishermen. Because of catch limits, quotas, and closure of seasons, triggerfish are frequently released after capture. We are interested in evaluating the survival rate of those fish that are released after suffering from barotrauma. We use SCUBA diving to establish more robust statistical practices when controlling for the effects of capture. My hope is that the results of this study will serve to better illuminate the effects of human interaction with our valuable aquatic resources.
Video: Underwater tagging of Gray Triggerfish
My team of expert scientific divers remove target fish from traps underwater. They then insert a tag with a unique fish ID number as well as a toll-free phone number for tag returns.
Descender Devices and Grouper
A Speckled Hind (Epinephelus drummondhayi) with an acoustic transmitter tag dorsally. Fish such as this one are tagged and re-pressurized using a descender device called a SeaQualizer.
Many species of once-prevalent reef fish have experienced declines in population due to their popularity as food. Species of grouper such as Snowy Grouper (Epinephelus niveatus
) and Speckled Hind (Epinephelus drummondhayi
) are some of the most notorious of this bunch. Due to their low numbers, these fish are the subject of strict harvest restrictions. These species frequently inhabit waters of 400’ or more, meaning when they are caught and brought to the surface they often suffer from severe barotrauma. Possibly the most detrimental effect of barotrauma in these species is their inability to swim back below the surface due to expanded internal gases. A section of my research is dedicated to learning whether it is possible to significantly increase the chances of survival after release of such individuals by forcing recompression using a tool called a descender device. Fish are attached to a weighted tool called a SeaQualizerTM
that is programmed to release the fish at a certain depth. We tag fish with acoustic transmitters and track their movements to determine whether they survived the capture and release event.
Recompression of Speckled Hind using SeaQualizer descender device