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Hybrid Sharks: Evidence of Species Resilience to Climate Change?

A recent article by Agence France-Presse (AFP) reports that Australian scientists have discovered the world’s first hybrid sharks in Australian waters. The article, based on results published in Conservation Genetics, could challenge ideas of how sharks had and continue to evolve; namely, how these species are adapting to cope with warmer temperatures driven by climate change in Australian waters.

The Australian black-tip shark has been mating with the common black-tip (its global counterpart) to create a hybrid shark. Intrigued scientists at the University of Queensland and James Cook University describe this phenomenon as truly unprecedented and even as “evolution in action.”

The implications of this development are significant for those studying climate change impacts and their effects on biodiversity. The Australian black-tip shark can only live in tropical waters, but its hybrid offspring have been found 2,000 kilometres down the coast in cooler seas. This may suggest that the species has found a way to adapt to cooler waters to ensure its survival as sea temperatures rise around Australia due to climate change. A number of additional climate-driven factors may be attributed to such species migration, including ocean acidification, the increase in ocean acidity caused by uptake of excess carbon dioxide.

While some aspects of the hybridization process remain a puzzle, scientists say they there is no doubt that the species is adapting, and as a result has become more resilient to the impacts of climate change.

The results from the article draw a parallel to the findings and recommendations of the ACT Climate Change Adaptation and Biodiversity report. This report, released in 2009 and written by ACT’s first policy author, former BC Deputy Minister of Sustainable Resource Management, Jon O’Riordan, found that all types of species are vulnerable to climate change, and their resilience to climate impacts may require a change in resource management techniques. Please click here [pdf] for the summary report.

A major recommendation outlined in the ACT report is that ecosystems, like water resources, cross jurisdictional boundaries. To maintain ecosystem resiliency, the report recommends that all levels of government in BC make a transition to an ecosystem-based approach to resource management on a terrestrial and watershed basis. This could improve management, provide better information and allow scientists to observe changes in ecosystems more carefully, to ensure that species are protected in light of changing climate conditions.

Just as the hybridization of the black tip shark in Australia will affect its environment, the dynamics and uncertainties of climate change are altering ecosystems, changing migration patterns, evolutionary traits and challenging species resiliency with mixed results. Decision-makers can help the capacity of scientists to observe these changes, and stimulate a variety of measures to help species adapt to climate change.

An ecosystem-based approach integrates the management of land, water and ecosystem resources in a way that promotes long-term conservation and sustainable use. This approach could be considered by jurisdictions around the world as they too witness changes in their ecosystems, such as the hybridization of sharks.

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