Reaching lengths of just 75cm, shorttail nurse sharks are a far cry from the impressive great whites we think of when we hear the word ‘shark’. But despite being small, these babies of the shark world are not afraid of travelling big distances.
Located over 400km south of LTO’s base in Jangamo Bay, Inhambane, the Ponta do Ouro marine reserve has recently recorded several sightings of the Critically Endangered shorttail nurse shark.
Migrating over 2000km from their previously known habitats off the coasts of Tanzania and Madagascar, the latest sightings in Ponto do Ouro represent a huge southward range extension not previously documented for the species. While this may represent a shift to cooler waters, an individual sighting of a shorttail nurse shark in Mozambique back in 1967 suggests that decades of limited underwater observation may have left their current movements unnoticed.
Researchers from a study published this January in Marine Biodiversity suggest that the sharks are attracted to the relative safety of marine protected areas (MPAs), where they can chill out knowing that they are much less likely to fall victim to unsustainable fishing practices. While MPAs offer a refuge for these migrating sharks, there are worries that the species may still be at risk along Mozambique’s extensive areas of unprotected coral reef: including the coast at Jangamo Bay.
Using snazzy stereo baited remote underwater video (BRUV) surveys in May 2019, two specimens in the nurse shark family were recorded in Inhambane Province, right on LTO’s doorstep. The mature female sharks were recorded approximately 600m apart on coral reef at depths of 8m and 12m. After identification down to species level, these were confirmed as the long-distance swimming shorttail nurse sharks!
But with no current plans to regulate their harvest, Rhett Bennett, lead author of the study and Manager of the WCS Madagascar and Western Indian Ocean Shark and Ray Conservation Program, says, ‘the shorttail nurse shark is under threat within much of its Mozambique range.’
Having recently been reclassified by the IUCN from Vulnerable to Critically Endangered, shorttail nurse sharks are now at significant risk of being targeted by coastal fisheries, which exploit coral reefs for their rich abundances of fish. In response to the mounting pressure of unsustainable fishing practices and ongoing habitat degradation, scientists suspect populations of shorttail nurse shark, now dubbed Southern Africa’s most threatened endemic shark, have declined by 80 percent over the last 30 years.
While commercial fishing practices remain the most detrimental to shark populations on a global scale, artisanal fisheries operating close to the coast are the driving force of Mozambique’s fishing industry, responsible for more than 75% of landed marine fish captures. Therefore, by collaborating with fishermen, LTO is working with the indigenous communities of Jangamo Bay to educate residents about the importance of fishing sustainably to preserve fish populations for generations to come.
Looking beyond shorttail nurse sharks, globally, sharks have a pretty hard time. Contemporary research published in Nature indicates that oceanic sharks and rays have been on the decline for half a century, with a quarter of sharks now threatened with extinction as a result of targeted and incidental bycatch. In the Nature study led by Nathan Pacoureau, it is estimated that in the 50 years between 1970 and 2020, shark abundance declined by more than 70 percent. This highlights the need for rapid action to save (arguably the coolest) and most instantly recognisable predator in the ocean.
Although the prospect of a new species of shark on our shoreline is exciting, Jangamo Bay is not yet officially recognised as an MPA. With BRUV records for the endangered sharks located more than 200km from the nearest MPA, the need to designate our area with protected status to save them from extinction couldn’t be more vital!
Since the beginning of our journey, LTO’s biggest mission has been to get Jangamo Bay established as a Locally Managed Marine Area (LMMA). By continuing our community-led approach to lobby for change, we hope we can do our part to save these little guys and all the awesome marine fauna that finds its way into our waters!
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Written by Lily Holbrook