Greenland shark tissue collection (Photo by Ewan Camprisson)
Key highlights:
- The Greenland shark is the world’s longest-living vertebrate, with a lifespan that can exceed 500 years.
- A new study has found that muscle metabolic activity in Greenland sharks doesn’t change significantly with age.
- These findings suggest that a stable metabolism may contribute to extended lifespan.
- This research has implications for both conservation efforts and human cardiovascular health.
- Further studies are planned to investigate more enzymes and tissue types to gain a deeper understanding of shark metabolism.
Recent experimental studies have highlighted that muscle metabolic activity may play a key role in the extraordinary longevity of the Greenland shark (Somniosus microcephalus), the world’s longest-lived vertebrate. These findings may inform conservation strategies for this vulnerable species in the context of climate change and provide new perspectives on human cardiovascular health.
Greenland sharks have an extraordinary lifespan, living at least 270 years and possibly more than 500 years. Understanding the adaptations that allow these sharks to achieve such longevity is crucial, according to Ewan Camplisson, a PhD student at the University of Manchester, UK. Previous hypotheses suggested that the main factors contributing to these sharks’ long lifespans were their cold environment and low activity levels. However, Camplisson and his team found that the mechanism is much more complex.
The team wanted to determine whether Greenland sharks exhibited typical signs of ageing, such as changes in metabolism over time. To do this, they performed enzyme analyses on preserved muscle tissue samples from Greenland sharks of different ages and used a spectrophotometer to measure the metabolic activity of these enzymes at different environmental temperatures.
In contrast to what is observed in most species, the study found no significant changes in muscle metabolic activity between sharks of different ages. This stability suggests that the Greenland shark’s metabolism does not decline over time, possibly contributing to its longevity. “This is quite different from most animals, which tend to show some changes in metabolic enzyme activity as they age,” Camplison points out. “The results support our hypothesis that Greenland sharks do not show general signs of aging.”
Additionally, the study found that metabolic enzymes in Greenland sharks are more active at higher temperatures. This indicates that the shark’s red muscle metabolism is not specifically adapted to polar environments; if it were, it would vary less with temperature. This adaptability in enzyme activity could also be a factor in the Greenland shark’s resilience, but it also raises concerns about its vulnerability to climate change. “Female Greenland sharks may not reach sexual maturity until they are 150 years old,” Camplison explains. “With a long generation period, this species has less opportunity to adapt to anthropogenic changes in its environment.”
Camplison plans to expand his research to include more enzymes and tissue types to gain a deeper understanding of the metabolic activity of Greenland sharks. His ultimate goal is to better understand these animals and thus enhance conservation efforts. Additionally, Camplison believes this research could have applications in understanding human cardiovascular health, as studying Greenland shark hearts could provide insight into the aging process that affects the human heart.
The research was presented at the Society for Experimental Biology Annual Meeting, held July 2-5, 2024 in Prague.
Credit: Society for Experimental Biology
