Fluctuations in seawater temperature are responsible for responsible for the ups and downs in the abundance of marine fish stocks. This is the conclusion from the study by Wageningen University & Research. Fish biologists have noted slow fluctuations in fish stocks for centuries. Though the cause behind it remained unclear. The new study pointed out fluctuations on timescales of decades are present in fish populations. This happens because of their sensitivity to water temperature.
Fish population’s respond to temperature depends on the species’ lifespan and its position in the food chain. Short-lived fish feed on plankton. So, a favorable year in terms of climate leads to population growth. But this effect is slower in long-lived predatory fish.
The study can provide insight into the effects of climate change on marine fish populations. Climate change will lead to a gradual increase in seawater temperature. It will also lead to a stronger year-to-year fluctuations in fish populations. Scientists also ran simulations using climate change scenarios.
Annual rings in fish bones
The basis for this study is formed on growth rings in fish. Scientists used annual ring data to establish the linkages between seawater temperature and fish growth.
But this did not explain the slow fluctuations in fish populations. In the next step, scientists will scale up the growth of individual fish to that of populations. This research paper has been published in Communications Biology.