Researchers have been telling us for the past decade how human activities such as tuna fishing and dolphin-watching tours put stress on wild dolphins; stress they can ill afford with the existing pressure of our chemical contaminated oceans. Now a new study by researchers from the Marine Genomics Group has identified a new stressor – researchers themselves.
Blood samples from wild bottlenose dolphins (Tursiops truncatus) in a capture-release health survey were subjected to transcriptomic analysis. Transcriptomics involves studying gene expression by examining the RNA or transcripts (messenger molecules which code for proteins) in cells. The number and type of transcripts change over time in response to stimuli. In the bottlenose dolphins it was found that levels of some transcripts significantly increased (they were up-regulated) following veterinary examination, indicating greater stress on the animals than expected.
Genes involved with energy generation and immune function were up-regulated, particularly those concerned with infection response and inflammation. One of these was IL-8, a gene which codes for a chemokine involved in the migration of cells to the site of inflammation. If produced in excess it can lead to the damage of healthy tissue. The up-regulation of these genes corresponds with an acute-phase response, a defense system seen during acute illness or trauma.
So in examining wild dolphins to further conservation efforts, researchers are actually having a negative impact on dolphins’ health and well-being. Maybe this time it’s Flipper who needs rescuing.
By Belinda Cosgrove41410228
Primary Source - A. Mancia, G. W. Warr, R. W. Chapman (2008) A transcriptomic analysis of the stress induced by capture-release health assessment studies in wild dolphins (Tursiops truncatus), Molecular Ecology 17 (11).
Secondary sources
- http://student.ccbcmd.edu/courses/bio141/lecguide/unit4/innate/acutephase.html
- http://student.ccbcmd.edu/courses/bio141/lecguide/unit4/innate/cytokines_in.html
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