Changing Oceans: How can climate change lead to less fish catch?

currentsblog_changingoceans1_2By Teressa Pucylowski

Everyone on this earth has one thing in common: we all need an adequate and nutritional diet to survive, a fact that is encompassed in the concept of “food security”. Sadly, the onset of climate change threatens food security for a large number of people in this world. The effects of climate change on food sources varies between land and sea in terms of magnitude and intensity. For those who depend on the oceans for food, the consequences of climate change could pose serious risk to their ability to maintain enough catch.

currentsblog_changingoceans2
Local fishermen with tuna catch Sulu Sea, Philippines © Jürgen FREUND / WWF

For the marine environment, a changing climate means rising sea temperatures and increasing ocean acidity which can lead to other events such as altered ocean currents and redistribution of nutrients. Changes to the physical environment will in turn create changes in the abundance, health, and distribution of marine populations that are harvested for seafood. For example, finfish such as tuna, will migrate poleward toward cooler waters leaving fisherman near the equator disadvantaged. Marine habitat will also be affected: corrosive seas degrade coral reefs and mangroves leaving less available space for fish to live. This means less fish available to fishermen and therefore less fish for people to eat. A recent Nature article published by Golden et al. (2016) describes this scenario as it is anticipated to be felt by coastal communities as well as the nutritional implications for those in parts of the globe most likely to be affected: particularly poor, isolated populations.

This is a major problem…

 … A problem that is magnified in small island communities who rely on fishing as a main source of food, such as the Pacific Islands. In the Pacific Islands locals and fishermen have expressed concern about how they will adapt to the projected changes in fishing success for years to come. Albacore, skipjack, bigeye, and yellowfin – these species of tuna are major fisheries in the Pacific Ocean and their current ranges are expected to change as water temperatures steadily increase.

currentsblog_changingoceans3Fish makes up about 50-90% of the dietary protein for people living in the Pacific Island Nations.

 

We often don’t think much about what fish we eat, who supplied it, and how it ended up on our plate – but these are topics that are going to become more and more important as the effects of climate change continue to unfold. The potential for fisheries catch to decline in the future is compounded by the fact that supplemental sources of food will become less available due to climate change: crop yields will decrease as a result of warmer temperatures, less rainfall, new pest invasions, etc. Combine this with a growing human population – 9.5 billion by 2050 – and the issue becomes more dramatic.

The good news is that there are proposed solutions to these issues. Some possibilities include creating a market for fisheries that have not yet been explored or changing the geographic location of ocean fisheries to match the projected migration of fish in the face of warming seas. With respect to the valuable tuna industry, creating artificial habitat can be used to rebuild populations.

It is important that we are all aware of the concerns of climate change as it is likely that the effects will reverberate globally and be experienced by all. Everyone deserves access to a sufficient nutritional diet; hence addressing food issues is of utmost importance. In order to be successful in securing food for all human life, we must work on creating solutions to climate-related problems while adapting to change.

References for further reading

  1. Barange, M. Merino, G., Blanchard, J.L., Scholtens, J., Harle, J., Allison, E.H., Allen, J.I., Holt, J., & Jennings, S. (2014) Impacts of climate change on marine ecosystem production in societies dependent on fisheries. Nature Climate Change: 4, 211-216.
  1. Bell, J. (2007). Fish – cornerstone of future food security?: Finding ways to maximise resource. Islands Business. p. 44.
  1. Bell, J.D., Kronen, M., Vunisea, A., Nash, W.J., Keeble, G., Demmke, A., Pontifex, S., & Andrefouet, S. (2008). Planning the use of fish for food security in the Pacific. Marine Policy: 33, 64-76.
  1. Bell, J. D., Reid, C., Batty, M. J., Lehodey, P., Rodwell, L., Alistair, J. H., Johnson, J. E., & Demmke, A. (2012). Effects of climate change on oceanic fisheries in the tropical Pacific: implications for economic development and food security. Climate Change: 119, 199-212.
  1. Bell, J.D., Ganachaud, A., Gehrke, P.C., Griffiths, S.P., Hobday, A.J., Hoegh-Guldberg, O., Johnson, J.E., Le Borgne, R., Lehodey, P., Lough, J.M., Matear, R.J., Pickering, T.D., Pratchett, M.S., Sen Gupta A., Senina, I., & Waycott, M. (2013). Mixed responses of tropical Pacific fisheries and aquaculture to climate change. Nature Climate Change: 3(6), 591-599.
  1. Bell, J. & Taylor, M. (2015). Building climate-resilient food systems for Pacific Islands. Penan, Malaysia: WorldFish. Program Report: 2015-15.
  1. Cheung, W. W. L., Lam, V. W. Y., Sarmiento, J. L., Kearney, K., Watson, R., Zeller, D., & Pauly, D. (2010). Large-scale redistribution of maximum fisheries catch potential in the global ocean under climate change. Global Change Biology: 16, 24-35.
  1. Connell, J. (2015). Food security in the island Pacific: Is Micronesia as far away as ever? Regional Environmental Change: 15(7), 1299-1311.
  1. Food and Agriculture Organization of the United Nations (FAO). (2012). Strategy for fisheries, aquaculture and climate change. Framework and aims 2011-16. Rome, Italy. N.p.
  1. Golden, C.D., Allison, E.H., Cheung, W.W.L., Dey, M.M., Halpern, B.S., McCauley, D.J., Smith, M. & Vaitla, B. (2016). Nutrition: Fall in fish catch threatens human health. Nature: 534, 317–320.
  1. Ganachaud, A., Sen Gupta, A., Brown, J. N., Evans, K., Maes, C., Muir, L. C., & Graham, F. S. (2013). Projected changes in the tropical Pacific Ocean of importance to tuna fisheries. Climate Change: 119, 163-179.
  1. Huelsenbeck, M. (2012). Ocean-based food security threatened in a high CO2 world: A ranking of nations’ vulnerability to climate change and ocean acidification. Washington D.C.: Oceana. N.p.,2012, print.
  1. Porter, J.R., & Xie, L. (2014). Food security and food production systems. In: Climate change 2014: Impacts, adaptation and vulnerability. Part A: Global and sectoral aspects. Contribution of working group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 485-533.
  1. Rice, J. C. & Garcia, S. M. 2011. Fisheries, food security, climate change, and biodiversity: characteristics of the sector and perspectives on emerging issues. Journal of Marine Science: 68(6), 1343-1353.
  1. Rosenzweig, C. & Parry, M. 1994. Potential impact of climate change on word food supply. Nature: 367, 133-138.
  1. Secretariat of the Pacific Community (SPC). (2008). Fish and food security. Policy Brief. N.p. January 2008.
  1. Wetzel, F.T., Kissling, W.D., Beissmann, H., & Penn, D.J. (2012). Future climate change driven sea-level rise: secondary consequences from human displacement for island biodiversity. Global Change Biology: 18, 2707-2719.

Photos (in order):

  1. The Cook Islands: www.worldalldetails.com/Pictureview/5865-Unreal_Paradise_Cook_Islands_Lagoon_aerial_view.htm
  2. http://wwf.panda.org/wwf_news/?193034/Western-Pacific-island-states-taking-back-control-of-their-fisheries#
  3. Marco Care/Marine Photobank