Groupers: a delicacy in danger | WWF Hong Kong

Groupers: a delicacy in danger

31 March 2017

The vast majority of people in Hong Kong love eating seafood. From a per capita perspective, our seafood consumption is nearly the highest in Asia – we are second only to the Maldives, an island nation. Hong Kong is often ranked as one of the world’s top ten nations when it comes to consuming seafood, and live reef food fish – a classification which includes many species of groupers and the Humphead wrasse, are some of our city’s perennial favourites. Naturally it should come as no surprise that Hong Kong and mainland China are key trade and consumption hubs for these types of fish.

Statistics from Hong Kong reveal further surprising figures: in 2016 alone, Hong Kong recorded  imports of 12,200 metric tonnes of live groupers. About 60 per cent of groupers originated from the Coral Triangle – an area of sea bounded by the Philippines, Malaysia, Indonesia, Timor-Leste, Papua New Guinea and the Solomon Islands.

In Hong Kong, the live reef food fish trade includes around forty to fifty species of groupers. “Spotted groupers”, a group which includes the Leopard coralgrouper, Squaretail coralgrouper, Spotted coralgrouper, Blacksaddled coralgrouper, Roving coralgrouper and Highfin coralgrouper, is particularly popular with consumers. Unfortunately, many markets and supermarkets in Hong Kong frequently do not provide sufficient and accurate information about the seafood they sell to consumers – for example a product’s scientific name and country of origin. Given this general lack of information and the fact that consumers may not be able to tell different species of groupers apart, people may unknowingly purchase vulnerable or even endangered species from these markets. At the same time, this lack of information can mislead consumers and they may end up paying a higher price for a species that would normally command a lower price. WWF-Hong Kong found and revealed numerous cases of these labelling and pricing practices in supermarkets around Hong Kong, including several incidents related to coralgroupers (click here for more information on our research).
After these incidents were uncovered, the media began reporting on ways to tell different species of coralgroupers apart. While this is helpful, WWF-Hong Kong believes that consumers should also look beyond the species name and learn more about the little-told story of coralgroupers.

A mega-fish in decline

Coralgroupers are some of the largest groupers. Although the coralgroupers we usually encounter in markets and supermarkets are only around 30 – 50 cm in length, coralgroupers in the wild can easily reach 70 cm, with some like the Leopard coralgrouper, Blacksaddled coralgrouper, Spotted coralgrouper and Roving coralgrouper even reaching 120 – 130 cm in length. They are some of the largest predatory species living in coral reef ecosystems.

Notably, the results of several market surveys and underwater surveys reveal that the mature individuals of many grouper species, including coralgroupers, are becoming smaller and smaller in size. These results imply that the larger individuals of these species are becoming more scarce, and that these fishery resources are shrinking.

Late maturity and the ability to change sex

Many groupers can live for more than 10 years, with some even reaching 40 years of age! Given their relatively long lifespans, it takes a long time for groupers to mature and begin to reproduce. Groupers are one of the few species that can change sex naturally – the Leopard coralgrouper, Spotted coralgrouper and Blacksaddled coralgrouper change sex from female to male. The Leopard coralgrouper can live for at least 19 years. They take two to three years to reach maturity and start reproducing as females. After around seven years, the females then change sex and become male. The Blacksaddled coralgrouper can take as many as eight years to switch from female to male.

This interesting genetic quirk regrettably makes these species vulnerable to overfishing. This practice takes fish out of the marine ecosystem before they have time to grow, mature and reproduce. This in turn can lead to a gradual reduction in the size of these fish in the wild, and if the situation persists, an overall decline in mature individuals – ultimately creating devastating impacts on the productivity of coralgrouper fisheries.

Aggregating to spawn

Some groupers, including the Leopard coralgrouper and the Squaretail coralgrouper, are aggregate spawners. This means that mature individuals typically come together in the same place at approximately the same time each year in a “single species aggregation”, creating a greater-than-normal concentration of fish with one specific purpose: reproduction. Due to the predictability of these events and the fact that these valuable species come together in great numbers, these aggregations often present an irresistible target to fishermen, allowing them to harvest a huge number of mature individuals in a short time. Not only does this impact a species’ reproduction,  it can significantly reduce the total number of mature individuals over a wide area.

Current status of wild groupers

All groupers possess these “unlucky” genetic and reproductive characteristics which render them vulnerable to overfishing. This situation is fuelled in part by the huge demand for groupers in Hong Kong and mainland China and has led to a serious population decline in many wild grouper species. A 2012 study that examined 163 groupers revealed that Threatened species made up 12 per cent and Near Threatened species made up 13 per cent of the groupers assessed. Notably, about 30 per cent of the species in the study did not possess sufficient information for a proper assessment, meaning that more species may have been Threatened or Near Threatened, but instead they were listed as being Data Deficient. In late 2016, 35 grouper experts from 13 countries came together to re-assess several grouper species. Although data collection and analysis is still underway, the initial results have already revealed a gloomy outlook for many of these species, particularly those which form spawning aggregations.

You can make a difference!

It is hard for ordinary consumers like ourselves to become involved in fishery conservation work led by the government or environmental NGOs; nor can we easily contribute to scientific studies of groupers. However, an effective way to start turning the tide for groupers and other seafood species in decline starts with all of us making wiser and more responsible seafood choices.

We can all start doing this by downloading WWF-Hong Kong’s Seafood Guide mobile app. Then, we can stop and think before purchasing seafood – only choose seafood in the “Green” and “Yellow” categories of the Guide and avoid those in the “Red” category. Together, it is possible to ensure the long-term sustainable use of our marine resources!

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