Can fishing in the Ross Sea be sustainable? Leo Salas, Ph.D. [email protected]

Humans have removed 90% of Besides being the largest fish in feasible metrics to monitor the big fish from every ocean in Antarctic waters, toothfish is also include seal population numbers, the planet, except for the among the most energy-rich. breeding propensity, diving effort, Southern Ocean, especially the Because of these two factors, It and toothfish consumption rate. Ross Sea. But that may be has been suggested that toothfish changing. Since 2003, the largest may be critical for mass recovery Main Points (more than twice as big as the in mother seals. next species) fish in Antarctica is  Weddell seals may not Using all the scientific evidence being removed from the Ross Sea. recover sufficiently from available, the team constructed a nursing their pups without That fish is the Antarctic toothfish, the largest and model to determine how much toothfish, usually sold as Chilean among the most energy- energy the seals must consume seabass. The fishery target is to dense fish in Antarctic waters. reduce the total number of adult during the recovery period to maintain population numbers.  The toothfish fishery is toothfish by 50% over a 35 year likely already adversely That model was coupled with a period. affecting seal populations. simulation of prey consumption  The fishery may be Is the fishery affecting the to establish the role of toothfish sustainable at lower Antarctic ecosystem? If so, how, in sustaining seal populations. extraction rates.  Monitoring of seal and by how much? A team of The results show that some populations is important to researchers, led by Point Blue ensure this fishery is consumption of toothfish is Conservation Science, sought to sustainable. answer these questions by paramount for Weddell seals to maintain a stable population focusing on the potential impact numbers. There are substantial Salas, L., N. Nur, D. Ainley, J. of the fishery on a toothfish Burns, J. Rotella, and G. Ballard (in reasons to expect that Weddell press). Coping with the loss of predator, the Weddell seal. seal populations are already large, energy-dense prey: A potential bottleneck for Weddell Weddell seal mothers may lose as severely impacted by the fishery. Seals in the Ross Sea. Ecological much as 40% of their body mass Findings also suggest that the Applications. http://onlinelibrary.wiley.com/doi/10. while nursing their pups. To breed fishery may be sustainable at 1002/eap.1435/full again, they must recover this lower extraction rates. mass. How quickly they recover is This research highlights areas of also correlated with the chances their pup survives and reaches critical importance for further adulthood, all of which eventually study and monitoring to ensure that the fishery is managed affects seal population numbers. sustainably. Important and

January 2017, Point Blue Conservation Science visit www.pointblue.org/publication-briefs