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DNA-based technology could save Indonesian sharks

Millions of organisms contribute to global marine biodiversity, and most of them are in need of protection. Unfortunately, the planet has lost about 70% of its animal diversity in the last five decades. Indonesia, known for its rich marine diversity, is at the heart of this challenge. Researchers have discovered that Indonesian sharks and manta ray populations are vanishing at an alarming rate.

Indonesian sharks and rays

Sharks and rays are some of the biggest victims of declining marine biodiversity. Once considered apex predators, these elasmobranchs have become vulnerable ocean inhabitants fighting for survival. The biological characteristics of sharks and rays also put them at a significant disadvantage. They grow relatively slowly, mature late, and reproduce at very low rates. 

While this is a global crisis, Indonesia is taking a bigger hit than most countries worldwide. The country is home to over 220 shark and ray species, translating to one-fifth of the global population. Having such a rich diversity of sharks and rays comes with a few economic benefits. For example, shark tourism in the country contributes at least $22 million annually to the national coffers.

Despite their economic value, only six species are protected from all forms of catch and trade in Indonesia. These include whale sharks (Rhincodon typus), giant manta rays (Mobula birostris), reef manta rays (Mobula alfredi), and three sawfish species.

The country also does not allow the export of four globally endangered species: three hammerhead shark species and oceanic white-tip sharks (Carcharhinus longimanus).

Indonesian fisheries capture 86% of sharks

From 2007-2017, Indonesia’s shark and ray fishery recorded an annual average catch of 110,737 metric tons. This is the largest in the world.

Interestingly, the larger part of this weight comes from unintentional bycatch rather than intentional or active fishing. This aligns with the Wildlife Conservation Society‘s 2018 observation that up to 86% of Indonesian fisheries incidentally capture sharks and rays.

This situation leaves Indonesia with a crucial but tricky choice to make between conservation and the socioeconomic benefits of shark fishing.

Conservation efforts of Indonesian sharks

The recent efforts of Indonesian authorities indicate the readiness of the country to protect these endangered marine species from extinction.

According to a newly published study, the recent advancements in science and technology may offer the country a solution. New DNA-based diagnostic tools, such as the FASTFISH-ID method, have advanced the process of wildlife identification.

FASTFISH-ID shows great promise

FASTFISH-ID is an advanced real-time polymerase chain reaction (PCR) technique that supports rapid and reliable species identification. It uses fluorescent probes to create unique genetic signatures for each species, offering precise identification.

Initially designed for bony fishes, FASTFISH-ID has shown promise for elasmobranchs. Hence, researchers used it to generate fluorescent signatures for 28 frequently traded elasmobranch species found below the surface of Indonesian waters.

These signatures allowed for accurate species identification, although with a few misclassifications. The deep machine learning approach achieved an impressive 79.41% accuracy in species identification.

Game-changing technology

Andhika P. Prasetyo, a researcher at the University of Salford, led this vital work. Based on their findings, the experts believe the FASTFISH-ID could be a game-changer – offering speed, portability, universality, and single nucleotide resolution when identifying elasmobranch species.

While limitations like misassignments and inconsistencies in hybridizations have been observed, the scientists hope the ongoing improvements and database expansions will improve the technology.

“With further refinement, this method can improve monitoring of the elasmobranch trade worldwide, without a lab or species-specific assays,” they noted.

The findings of this study were first published in the journal iScience.

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