SixGill Sharks in County Clare

Many elasmobranchs (that’s sharks, skates and rays to the less-geeky among us) play a huge role in mediating our ecosystems as apex predators at the top of the food chain.

But take out these top predators and the whole system goes off balance, often reaching a new equilibrium that lacks complexity, has limited productivity and reduced economic value as a consequence of curtailed ecosystem service provisioning. The future of these degraded ecosystems in the face of ongoing environmental crises becomes increasingly bleak owing to their relatively lower adaptability and resilience.

Elasmobranchs are vulnerable in large part due to their large size (old age) at sexual maturity, slow growth and small number of offspring. For example, FjordStrong recently captured footage of a sixgill shark in Irish waters.

https://www.irishexaminer.com/lifestyle/people/arid-40349105.html

https://www.independent.ie/videos/researchers-film-large-prehistoric-looking-shark-off-co-clare-coast-40704198.html

These enormous living fossils reach maturity at around 18 years in the case of the females, and take two years to give birth. Unlike some species of fish who release millions of offspring, sixgill sharks only give birth to about 20 pups, of which researchers believe only a handful will survive the first year.

 

 

 

 

Even for species of elamsobranch that aren’t targeted directly by fisheries, their large size and long lifespan greatly increases their risk of ending up as by-catch – especially in bottom trawlers. Once on deck, it is doubtful that most individuals are correctly identified to the species level, resulting in effective monitoring of their populations being a near impossible challenge. This taxonomical uncertainty represents a huge Achilles heel to conservation efforts, as similar looking species may be faring very differently regarding the state of their populations and road to recovery.

How do we restore these populations?

First we need to know where they are, why they’re there, and how they’re doing,  but with fisheries data being incomplete and often unreliable, we need to fill these gaps. With populations under so much pressure from a myriad of factors (habitat destruction, fisheries, increasing ocean temperatures, reduced prey availability etc), the methods required must be sustainable, statistically robust and scalable in addition to being quick and cost-effective.

This is why FjordStrong provides a suite of non-invasive, sustainable video based solutions for marine biodiversity surveying. Along with our patented hardware, we are developing bespoke software to facilitate the analysis of large amounts of video data while making use of multispectral lighting and 3d imaging, paving the road to effective biodiversity monitoring.

Even with reliable data and effective monitoring of the current state of our oceans, it is critical that we bear in mind what our reference points truly reflect. It is a sad fact that a lot of our current ‘baselines’ are descriptive of an already plundered and degraded ecosystem. Consequently, we must go beyond our EU obligations and allow Ireland’s rich marine biodiversity to recover fully.

This will surely take decades, but as an island with an unrivalled connection to the Atlantic ocean both culturally and geographically, we have a chance to be a good news story to the rest of the EU and the entire world over the coming decades – beginning now.