The ultimate British dish--fish and chips--have takers all over the world. However, the fish served in the dish might actually be an endangered shark species.

A recent study, published in the journal Food Control, found shocking samples of endangered shark species in several fish filets served at more than 100 retailers in South Australia.

In the study, DNA barcoding was used to analyze the contents of “flake”--an umbrella term used for fish filets, and found many species in the mix that weren’t supposed to be there, including the short-fin mako and smooth hammerhead.

“Flake is a key part of traditional fish and chip sales in Australia, and this study aimed to evaluate the mislabelling rate associated with shark products sold under the umbrella term ‘flake’ and compare it with the Australian Fish Names Standard (AFNS) recommended guidelines and list of commercial designations,” the researchers wrote in the paper.

The DNA barcoding technique identified species in the flake using the mitochondrial COI gene. It is to be noted that all samples were not able to return a clear result. This might be due to lower DNA quality or damage from cooking and processing.

The researchers found at least nine species of sharks, including species labeled under the IUCN Red List as threatened and sharks that are under the Convention on International Trade in Endangered Species of Wild Fauna and Flora protection, according to IFLScience.

Unbelievably, only 27% of samples tested were in line with the AFNS guidelines of containing gummy shark--sustainably fished shark species recommended for consumption.

Moreover, only 11% of retailers were able to correctly identify the species they sold, while another 20% of the samples were mislabelled. The remaining only had ambiguous labeling.

“Among the diverse types of seafood fraud, mislabelling and species substitution is common, and have potential implications on human health, the economy, and species conservation,” the researchers wrote.

“Ultimately, the umbrella term flake allowed for species misrepresentation but DNA barcoding was an effective tool to test ambiguous labeling in processed and cooked shark meat products,” the authors concluded, “and can guide policy, management, and compliance efforts to mitigate mislabelling, empowering consumers to make informed decisions and champion sustainable seafood.”

Another recent study found that eating too much fish may increase the likelihood of skin cancer. It was found in the study that the participants who consumed about two servings of fish per week had a 22% risk of developing melanoma than those who consumed less. The same participants demonstrated a 28% higher risk of developing abnormal skin cells that could be precursors to cancer. “We speculate that our findings could possibly be attributed to contaminants in fish, such as polychlorinated biphenyls, dioxins, arsenic, and mercury,” one of the authors, Eunyoung Cho, said.