This weekend I got to drive down the same winding road that opened my horizon to the Pacific Ocean for the first time. This time, on my way back from an adventure to Portland, the coast felt more familiar. It was a place comprised of new memories and a coast that I now knew harbored an abundance of natural resources. One of these resources is the rockfish, a genus of fishes highly sought after for being both a delectable piece of seafood and hefty game fish. Rockfish, by the nature of how they reproduce– not mating until 20 years of age and producing very few offspring– are prone to overfishing. Understanding and assessing their population statuses are essential for conserving this ecologically vital species and managing its associated economically important fishery.
Studying their populations is easier said than done. Because many of the rockfish on the Oregon coast live in deep reefs and rocky habitats, the traditional benthic species stock assessment method of trawling cannot utilized; it would destroy both the habitats and the equipment. As a result, ODFW has been faced with the challenge of coming up with a new way to conduct stock assessments of Oregon rockfish. Instead of sending nets below, ODFW has suggested dropping cameras, known as benthic landers, instead. Benthic landers consist of two standard handheld video cameras sealed in a waterproof housing attached to a large metal frame. The landers are secured to a long piece of line and deployed over the side of a boat until they hit bottom. Once at the seafloor, the cameras record the surroundings for 15-20 minutes, and, fast forward a few steps, the footage eventually ends up on a computer server for ODFW scientists and interns, like me, to review.
A yelloweye rockfish, Sebastes ruberrimus, captured by a benthic lander
An average day in the office consists of me reviewing lander footage and identifying the species of rockfish, as well as any other benthic fish, that pass in front of the cameras. At the end of a video review, I go back and mark the frame in which I saw the most of each species; this is called the MaxN frame. The MaxN data is what I will be analyzing statistically in the future, specifically in regards to comparing daytime lander footage to nighttime lander footage. The implications of my research is to show empirically whether time of day affects surveying and answer questions in regards to when lander deployments should be done. The ODFW marine resources research team’s long-term goal is for landers be used as a surveying tool across the entire Oregon coast and provide accurate fisheries-independent data for rockfish stock assessments. Before then, many practicality and methodological questions must be answered. My research works to answer one of those questions–maybe more in the coming weeks– and help develop a safe, cost-effective means of assessing rockfish populations in Oregon and beyond.
This is a great example of science communication. Before I read this post, I didn’t know much about rockfish, stock assessment, or benthic landers, and in a few short paragraphs, I already have a much clearer picture about how these all come together for ODFW’s project and your research. Nicely written and good luck analyzing all that footage!
Are any other data collected along with the videos? Like physical habitat measurements (water temp, oxygen, etc.)?
Fascinating, I had no idea that rockfish didn’t mate until 20 years of age until I read this! You did a great job of explaining your research – it must be exciting to be involved in the beginning stages of a project that has such long-term implications.
Very interesting and meaningful work, and has implications for further use in the study of marine life on the difficult to access landscapes in our oceans with little or no impact on the environment or its inhabitants.