Wildlife
Shark tales: Canada’s great whites
As white sharks make their presence known off the coast of Atlantic Canada, researchers and locals want to know: should people be worried?
- 3712 words
- 15 minutes
Wildlife
Wildlife Wednesday: the Greenland shark’s secret to 500-year life
Plus: the mammoths of Vancouver Island, the sustainable beluga-hunting of the Inuvialuit, and how some coho salmon stay sea lice-free
Advertisement
Advertisement
In addition to resembling something you might find wedged in the back of your freezer, Greenland sharks are known for being the longest-living vertebrate on the planet. They have an average lifespan of at least 250 years with some estimates indicating they could live as long as 500 years. The reason for the shark’s lengthy life has until now been a mystery, largely because of the challenges involved in studying creatures that live deep beneath the Arctic and North Atlantic oceans.
In July, new information about the Greenland shark was presented at the Society of Experimental Biology Conference. This included the fact that the shark’s metabolism is likely the culprit behind its centuries of swimming. The shark’s metabolism allows it to convert food into energy and to use that energy to maintain its body, just as ours does. The striking difference is that the enzymes responsible for this process in Greenland sharks do not change or degrade over time. It seems that this is the result of the cold waters the sharks generally inhabit. The important role cold plays in the lives of Greenland sharks raises concerns for its conservation, however, as the temperatures of Earth’s oceans continue to rise due to climate change.
Island living
A recent study from Simon Fraser University has found that wooly mammoths appeared on Vancouver Island much earlier than initially thought. The remains of two mammoths had previously been carbon-dated as belonging to individuals from around 21,000 years ago. After receiving 16 samples from the Royal BC Museum and Courtenay and District Museum and Palaeontology Centre, the samples underwent carbon dating where the oldest sample found was 45,000 years old, and the youngest 23,000 years old.
This discovery paints a much clearer picture of the history of prehistoric life on the island. Researches have emphasized the importance of museum collections to assist in studies conducted in the field of life science, noting that mammoth remains are actually quite uncommon in B.C., despite their size. The public may be able to help as well — one sample was discovered by a a child in the gravel of a local playground. The study is part of a larger overall look at large animals in B.C.
Advertisement
Not bad for belugas
For more than 700 years the Inuvialuit have been hunting beluga whales in the Mackenzie Delta near the border between the Yukon and Northwest Territories. The hunts serve an important role for the Inuvialuit both in terms of culture and survival. Now researchers out of the University of Copenhagen and the University of Toronto have had the opportunity to examine how this persistent hunting over several centuries has impacted the beluga population in the area.
The team examined beluga remains from previous years to discover their genetic diversity and sex using a variety of techniques including isotope analysis and genetic simulations. They compared their findings from older samples to data collected from more recent remains provided by Inuvialuit hunters. According to the study, published on August 13, 2024, the data indicated that the hunting had not damaged the genetic diversity of the beluga population in any meaningful way. A fact that further reinforces the idea that Inuvialuit beluga hunting practices are sustainable.
Under the skin
Scientists at the University of Stirling in Scotland have discovered a gene in coho salmon that may help fight off sea lice in other salmon species.
Sea lice are a frequent issue in farmed salmon, feeding on the skin and fins of the fish and leaving lesions that can lead to infection. Their prevalence in fisheries may also pose a threat to wild salmon populations. However, researchers who performed gene sequencing on coho salmon found that their skin contains a specialized type of skin cell known as a keratinocyte, which triggers localised swelling when a sea louse attaches itself to the salmon. Eventually, this swelling can encapsulate and expel the lice.
Researchers state that gene to produce keratinocytes may be possible to place into other, more vulnerable salmon species through the use of gene editing. Current treatments for sea lice are extraordinarily expensive, costing hundreds of millions of dollars per year, and can have adverse effects on the environment and animal welfare.
Related Content
Wildlife
The great green shark hunt
Can British Columbia’s spiny dogfish make the grade as the world’s first “sustainable” shark fishery?
- 3319 words
- 14 minutes
Wildlife
Jawsome: behind the scenes of Canada’s newest great white shark documentary
Korean-Canadian filmmaker Sonya Lee dives deep into the world of great white sharks for the latest documentary from CBC’s The Nature of Things
- 1781 words
- 8 minutes
Wildlife
Study finds reef sharks ‘functionally extinct’ from 20 per cent of the world’s reefs
Lead author Aaron MacNeil discusses what this means for coral ecosystems and what Canadians can do to help
- 1375 words
- 6 minutes
Advertisement
Advertisement