Faculty Feature: Trevor Branch

Trevor Branch  (photo by Alex Zerbini)

MD: Can you describe your PhD research?

TB: Under Ray Hilborn’s direction, I studied the effect of individual transferable quotas (ITQs) on fishing behavior: how ITQs affected discards and when people fish. I compared two fisheries—one in British Columbia using an ITQ system, and the other on the West Coast, which limited allowable catch of a species by two-month periods for each boat.

The BC people fished very differently, discarding less, catching their full quota, and avoiding overfishing. While the West Coast fisheries were allowed to exceed the species quota, excess had to be discarded—very wasteful. ITQs set a fixed quota including discards, which motivates fishermen to improve their fishing techniques.

Primarily, I looked at spatial changes. There’s a lot of movement and year-to-year variability. If you have a constraint on a species, say because they have low numbers, and you’re likely to catch them, an ITQ system encourages you to avoid areas where these fish occur. Fishers are increasingly sharing information to help others avoid exceeding quota. Also, if you do exceed your quota, you can lease quota from others if they’re willing. Now, the West Coast has shifted to the ITQ system as well.

MD: After earning your PhD, you spent a couple of years conducting research on southern bluefin tuna and blue whales back in Cape Town, and then returned to SAFS in 2007.

I returned to Cape Town and worked for the Commission for the Conservation of Southern Bluefin Tuna. This species is very overfished. Most of the controversy centers on the Atlantic, which is interesting since the southern stocks are more depleted. They’re below 10% of historical numbers and still being fished fairly hard.

Because multiple countries are fishing the same stock, it’s been very difficult to get everyone to agree to reduce fishing effort. Catches have come down from 35,000 to 10,000 metric tons, but they need to come down further.

I also did a lot of blue whale and humpback whale research, looking at where they occurred, trends over time, how to separate sub-species out, and minimum abundance.

I returned to SAFS to develop run reconstruction models to distinguish stocks of Bristol Bay sockeye salmon, which migrated to different rivers but were caught all together. I also conducted some global scale analyses—the state of global fisheries—that brought together a group of scientists including Boris Worm and Ray Hilborn.

MD: This was pursuant to the Boris Worm publication that raised considerable controversy.

TB: In 2006, Boris and several co-authors published a paper that had little to do with predicting fisheries collapse. But, they included one brief sentence that predicted the collapse of all fisheries by 2048, which got the attention of the press.

The paper was heavily criticized, including by Ray and me. Then, Ray and Boris decided to work together to arrive at some consensus. Working with people with such different perspectives was one of the most rewarding experiences I’ve had.

In the resulting 2009 Science article, we noted that while biomass is low, the fishing pressure is lower than expected. Projections show that most fisheries should rebuild and get better. It was the first sign that fisheries aren’t on a continuous downslope towards complete collapse. There are signs of recovery—not everywhere, but in many instances.

MD: You continued this focus in a more recent study on trophic levels and catch data.

TB: Daniel Pauly published one of the most highly cited papers of all time—Fishing Down the Marine Food Webs—in which he said that we first fished out the big fish, then moved down the web and, eventually, all that will remain is jellyfish and plankton.

He based this conclusion on catch data, which can vary because of management, economics, and many other factors. Instead, I thought we should look at what’s in the ecosystem, using surveys and assessments, which we had compiled for the Science paper. We also used ecosystem models to predict what you’d likely see. We found that catches of many top predators, instead of declining, have been increasing for some time. At virtually every level of the food web we’re catching more than ever. However, we have also increased fishing pressure, and that’s not good, either. We published our findings in Nature last year.

MD: Last September, you joined the SAFS faculty.

TB: I was very fortunate to get this position, which arose from a collaboration among SAFS, the College of the Environment, and NOAA Fisheries to hire two new faculty with strong quantitative skills. The goal is to increase the number of people we train who will be useful to NOAA. I look forward to taking on students and teaching, as well as expanding my research program.

MD: You already taught a class last winter.

TB: I coordinated the Bevan Series on Sustainable Fisheries, which included undergraduate and graduate discussion courses focusing on seminar topics.

This series invites speakers from across the USA and other countries—and not just scientists: we’ve had politicians and film makers—and always draws a good crowd. I'll coordinate next year’s series as well, which will be more general instead of focusing on a specific topic. This year, the focus was on ocean acidification.

Also, I will be teaching a new course on how to do graphics in the programming language, R, in Fall 2011. And in spring 2012, I’ll be teaching Fish 458, the modeling course that Ray Hilborn has taught for many years.