Marine biologist gives second talk of Year of Environment

Boris Worm speaks on overfishing, climate change and better ocean management

Earth’s oceans face a gloomy future, and our limited understanding of them may preclude ensuring their protection. Marine ecologist Boris Worm spoke on this topic on Monday, Nov. 16 in the second President’s Speakers Series event for the Year of the Environment. Worm outlined how the oceans are critically imperiled by climate change and overfishing, and how we cannot adequately protect them without first better understanding them.
“We are seeing the world as stationary with noise, you assume things will keep going as they are going,” said Worm. “Our hypothesis is that this is wrong, because the environment is changing.”
Worm is a professor in the biology department at Dalhousie University and studies how fisheries and marine life are responding to a changing world. He said that the models we use to decide where and how to catch fish often don’t consider climate change and other ecological variables, such as how fishes’ prey respond to climate and environmental changes.
“It was fascinating to hear in such an interesting format how connected so many industries are, like fisheries, and how they’re affected by environmental changes and how rapidly we have to adapt to changes,” said Sebastian Carrera, a fourth-year psychology student who attended the talk.
As an introduction to his talk, Worm said that since 1995 we have increased our efforts to catch fish but the amount of fish we have actually caught has declined. This is in spite of the increased efforts to protect certain fish stocks, which in some cases has caused fishermen to target new and unregulated species like sharks. A sobering fact featured in Worm’s talk was if current practices continue, there may too few fish in the ocean to catch any at all by 2050.
Increasing fishing pressure on marine life is compounded by the effect of climate change on global oceans. Worm showed how, as Earth’s oceans warm, many fish populations are shifting toward the poles, where fishing regulations may not protect them or where they may not be accounted for in population counts.
“We’ve become very aware now that the fishes we’re managing are moving targets in a spatial sense, so geographically the distribution of these fish are changing wildly,” said Worm.
Worm said that due to these changes, fish stock assessments are increasingly inaccurate in predicting how many fish we can sustainably catch. The cod fishery in the Gulf of Maine is a recent example Worm provided. Fisheries scientists assumed these cod were well managed, but didn’t account for how the Gulf of Maine was warming faster than 99 per cent of the ocean, which led their population to collapse.
“This is also a form of overfishing, but we call this ‘silent overfishing’ […] it was overfishing because we weren’t aware of the underlying problem in the ecosystem,” said Worm. “When we find out what’s happened to the stock, it’s already too late.”
Irena Kaczmarska, a biology professor and one of the talk’s organizers, said she was pleased to see a President’s Speakers Series talk focused on science.
“I think we should have more [talks on science]. We have a sizeable science student body – they should have these kinds of talks as well,” said Kaczmarska. “The combination of the data with the social interpretation and policy implication could speak to both science students and generally interested people.”

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