Saving the bright side of the sea

04 March 2010 | News story

There are two sides to Yvonne Sadovy’s passion: one unveils the colourful, inspiring and spectacular nature of the oceans, while the other reveals the destructive impacts of unsustainable international species trade and the consequences that this can have on fishing communities and marine ecosystems.

Mandarinfish
Mandarinfish
Her work combines scientific research and education, with investigations into the trade in reef fishes, one of the most colourful and diverse groups of marine animals. Many of these species are highly vulnerable to over-exploitation. Yet, with few controls and little concern for sustainability, they are being increasingly targeted globally for luxury seafood export markets, and as attractive aquarium fishes. If nothing changes, some of these species may disappear forever, a loss both to marine biodiversity and to the people who depend on it.

As co-Chair of IUCN’s Groupers and Wrasses Specialist Group, Professor Yvonne Sadovy’s work focuses on securing a future for a group of species that depend on rocky and coral reef habitat, most of which is easily accessible to fishing. Although most of these reef fishes produce large numbers of eggs each year, their rates of population growth are very slow. Their high value in the live fish trade, however, makes them a particularly appealing target; juveniles as well as adults are taken, making the species’ future even more insecure.
 

"Reef fishes have fascinated me by their colours and variety since I first saw them in books and on TV as a child. I was inspired to actually work with them when I discovered some of their wonderful behaviours. For example, not only do many of them change sex as adults but they do this in response to changes in their social system. It fascinated me that many fishes have this behaviour and I wanted to study them in their natural environment; it was a natural match of my love for water and for animals. As I came to understand the biology of the animals through my field-work in the Caribbean, I also came to realize how fishing could disrupt the fishes’ social systems and affect their reproduction in ways that could threaten them . For example, fishing the largest fish selectively removes males in species that change from female to male, as many of the groupers do, and can affect their reproduction. This, in turn, can lead to smaller populations, negatively affecting both the fish and the fishing communities that depend on them."

This early work led her to what she does today, which focuses on commercially-important reef fishes that are also particularly vulnerable to fishing because of their biology.

"I think of such species as the ‘tip of the iceberg’; if we cannot learn to manage these sustainably then we will lose them. The cycle will then repeat itself, with loss of the next most vulnerable group of species, and so on. The species I work most on are those that are very easily overfished because they live a long time (many decades) and so, do not quickly replace themselves when fished. Some of the species also have a special time in their life that makes them exceptionally vulnerable to fishing. For example, many of the groupers not only change sex and live a long time, but also spawn (reproduce) in very large aggregations. These fantastic spawning aggregations can include tens of thousands of fish for a few weeks each year but they are easy to eliminate very quickly by fishing if they are not managed."

One of Yvonne’s ongoing projects aims at developing a sustainable management plan for the iconic Humphead wrasse, also known as the Napoleon fish, one of the biggest reef fishes in the world. Considered in some countries to be a ‘stately’ or ‘royal’ fish, and prized historically for its flavour and texture, the Humphead wrasse has recently become highly valued in the restaurant trade in Southeast Asia. It is among the most highly priced of all fish species in international trade, its price often exceeding US$ 100 per kilogramme to consumers. In 1996, the species was listed as Vulnerable in the IUCN Red List of Threatened Species and in 2004 was upgraded to Endangered. Since 2004, it has been listed on Appendix II of the Convention on International Trade in Endangered Species (CITES). This list includes species in which trade must be controlled so as not to threaten their survival and such that exports are sustainably managed. It is hoped that additional measures will be agreed during the 15th meeting of the Conference of the Parties, which takes place from 13th - 25th March in Doha this year, that will improve enforcement of the Appendix II listing.

"The IUCN Specialist Group I represent will be in Doha to provide expert information and support as needed. We have, in the past, worked closely with the major importers and exporters of the Humphead wrasse and are aware of the key issues and challenges. We aim to support governments to manage this species in whatever way we can and whenever we are needed.
The Appendix II listing is the first of its kind for a coral reef food fish. It is my wish to see the Appendix II listing for the Humphead wrasse be successful because this could then be a role model for other fishes; a demonstration that the listing can be meaningful for conserving both the species and the trade that depends on its healthy populations."

Yvonne Sadovy was born in London, UK, and received her PhD in 1986 from the University of Manchester. She then worked as Director of the Fisheries Research Laboratory of the government of Puerto Rico’s Department of Natural Resources,and then as biologist with the Caribbean Fishery Management Council of the National Marine Fisheries Service. In 1993, she took up her current teaching post at the University of Hong Kong in 1993, where she is now a full Professor, continuing her research on the biology, fisheries and conservation of commercially-important reef fishes, and educating future generations of marine biologists and conservationists.

As well as co-chairing and founding IUCN’s Specialist Group Professor Sadovy is also Director and co-founder of the Society for the Conservation of Reef Fish Aggregations

Visit Yvonne Sadovy's photo gallery with some colourful images from the sea: