Pollution, Overfishing, and Framing Biodiversity Issues

Have you ever noticed how environmentalists tend to talk about ecology and the environment as if we humans aren’t part of the Earth’s ecosystems? That’s silly. With very few exceptions, all humans live on Earth in environments of Earth resources.

Exception (sort of)

For the most part, the environmental movement doesn’t recognize that the ways people change and engineer ecosystems are not necessarily bad, and are certainly not ‘unnatural.’ This mentality can put environmentalists at odds with people they should be allied with, like farmers and fishing communities. For me, changing how I thought about people in ecosystems changed the questions I asked about environmental issues.

Instead of asking questions like ‘How do we protect ecosystems? How do we prevent environmental damage? How do we balance our needs and the needs of the environment?‘, which imply humans are all-powerful destroyers in nature, we can instead ask ‘How can we make our environment better? What environmental changes would improve human well-being and survival? How does our role in the ecosystem complement the roles of other organisms?

I like the second set of questions better! It promotes a more productive framing of environmental issues, and I bet most people can think of better and less contentious answers to the second set of questions.

I bring this framing up because without it, I think the next part of this post might make you feel hopeless. And hopeless won’t solve many problems.

ResearchBlogging.org I wrote here and here about what Michael Novacek and Elsa Cleland have to say about the biodiversity crisis and how the current extinction event is different from past extinction event. They also lay out what they see as some serious threats to biodiversity. There are an awful lot of them. Depending on whether you’re a glass-half-empty or a glass-half-full kind of person, you could see the number of issues as an endless game of whack-a-mole or endless ways to make a dent in the extinction rate.

So, what did Novacek and Cleland think were the biggest biodiversity threats back in 2001?


We’ve done a lot to limit pollution (Hooray Clean Water Act!), but there’s definitely room for improvement. While any 8 year old can tell you that pollution is bad, defining what chemicals in what amounts in what places count as pollution is not simple. For example

The devastation of the coral reefs, sea grasses, and kelps in the Caribbean has been promoted by the loss of benthic producers whose viable populations in turn may have been greatly reduced by pollutants in runoff released through human activity along the shoreline (8, 9)

So we notice that the corals are dying, but we have to climb through several layers of the system to find out that the ultimate cause is related to pollution. Drawing those connections requires a lot of money and time. Turning that research into enforceable and fair laws takes even more money and work. But what if instead of focusing on what we should stop doing, we asked What human shoreline activities promote healthy oceans? or What ecosystems do humans live best in?


What fish do for us. From Holmlund & Hammer 1999

Most of the food we eat comes from farming where overharvesting isn’t a real issue – you don’t want to leave crops in the field. Overharvesting is a problem for food that doesn’t usually come from farms – like fish. People have gotten really good at catching fish and our demand reshapes marine food webs:

Marine fisheries respond to food demand with catches often comprising large species, lopping off each summit of the food pyramid as populations of larger, top-level consumers are virtually eradicated.1

Many fisheries have completely collapsed or are in danger of doing so if we don’t do something differently. And it isn’t just big fish that are in trouble – even quickly reproducing little fish like sardines can run into problems from people.2 But when fish run into problems from people, it also means problems for people. Apart from the obvious effect of less food for hungry people, damaged fish populations are bad for people in a lot of other ways: certain diseases, like malaria, become more prevalent, algae go nuts, etc.3 Hurting one fish population also makes it harder to keep other fish and marine species populations healthy and it is often difficult or impossible to nurse a population back to health.4 And there are an awful lot of fish species that need nursing back to health:63% of fish species (the ones we’ve checked, anyway) need to be ‘rebuilt’. 5

One of the big challenges for stopping overfishing is employment. Overfishing actually means more jobs in the short to medium term because when fish are rarer, it takes more work to catch them.5 But in the long term, of course, overfishing leads to catastrophic job loss. While fewer fish mean more jobs, no fish mean no jobs and a whole lot of other problems to boot.

Bycatch is also a huge issue – a huge percentage of the stuff caught isn’t what the fishers were trying to catch. This stuff dies and just gets tossed. There’s no real monetary value associated with avoiding most bycatch, but bycatch does have negative consequences for people through reduced ecosystem services.

We try to control overfishing by restricting catches or prohibiting fishing in some places. This usually hurts communities and really pisses off fishers. I wonder how our current strategies would be different if instead we asked What kind of fishing helps fish populations? Are there ways to use bycatch? Could we create jobs for bycatch reduction? What kind of fishing sustainably and equitably employs and feeds the most people?

Not quite the end

Novacek and Cleland discuss four more big ways people are wiping out biodiversity, but you’ll have to wait a bit for those. Some of them will require some cool ecological explanations and deserve their own posts. Besides, I don’t trust your attention span long enough to go through all six issues in one post!

Read the papers!

1 Novacek, M. (2001). The current biodiversity extinction event: Scenarios for mitigation and recovery Proceedings of the National Academy of Sciences, 98 (10), 5466-5470 DOI: 10.1073/pnas.091093698
2 Pinsky, M., Jensen, O., Ricard, D., & Palumbi, S. (2011). Unexpected patterns of fisheries collapse in the world’s oceans Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1015313108
3 Holmlund, C. (1999). Ecosystem services generated by fish populations Ecological Economics, 29 (2), 253-268 DOI: 10.1016/S0921-8009(99)00015-4
4 Worm B, Barbier EB, Beaumont N, Duffy JE, Folke C, Halpern BS, Jackson JB, Lotze HK, Micheli F, Palumbi SR, Sala E, Selkoe KA, Stachowicz JJ, & Watson R (2006). Impacts of biodiversity loss on ocean ecosystem services. Science (New York, N.Y.), 314 (5800), 787-90 PMID: 17082450
5 Worm, B., Hilborn, R., Baum, J., Branch, T., Collie, J., Costello, C., Fogarty, M., Fulton, E., Hutchings, J., Jennings, S., Jensen, O., Lotze, H., Mace, P., McClanahan, T., Minto, C., Palumbi, S., Parma, A., Ricard, D., Rosenberg, A., Watson, R., & Zeller, D. (2009). Rebuilding Global Fisheries Science, 325 (5940), 578-585 DOI: 10.1126/science.1173146