PhD student Xiong Zhang (@Harry01301) is mapping Chinese seahorse populations and the threats they face, both from overfishing and habitat loss.

China is the world’s largest importer and consumer of dried seahorses, thanks mainly to demand for the animals as ingredients in traditional medicine. Little is known, however, about wild seahorse populations within the country’s own maritime borders.

 Xiong's work has identified conservation priorities, and is informing fisheries policy and the creation of new marine protected areas, which are still relatively rare in China. 

Project details

Click on the map hotspots for more information.

Setting priorities to protect habitats of species in situ (i.e. conservation prioritization) has become a critical strategy in biodiversity conservation, as resources are usually limited. Marine ecosystems are facing increasing threats from land- and ocean-based human pressures. However, we are lacking a system to prioritize marine species, especially considering the complexity of socioeconomic contexts. Only a few initiatives have been conducted for marine animals, such as coastal fishes, sea turtles, and sharks at large spatial scales. Little research focused on rare and threatened (R&T) marine fish. 

Seahorses are charismatic representatives of R&T marine fishes and have served as flagship species for many conservation initiatives. Of the 42 seahorse species, 2 are Endangered, 12 are Vulnerable and 19 are “Data Deficient” on the IUCN Red List (,  January 2018). Over the past few decades, scientific research and citizen science has begun to enrich databases about seahorse distribution, habitat use, and human pressures. 

My PhD research explored the use of these resources to advance conservation prioritization of rare/threatened marine fishes, with a specific focus on seahorse species.

How to set conservation priorities?

Two types of maps are critical when conducting conservation prioritization. One is the distribution map of species under concern – usually threatened or impacted species by human activities. Species distribution models are commonly used to generate this map based on species-presence data and environmental maps. The other map is the cumulative human impacts upon the concerned species. Cumulative impacts can be qualified and mapped through methods derived from decision science and spatial analysis techniques. 

Another vital set of information is that of socioeconomic costs for the protected areas identified through conservation prioritization. Current marine protected areas (MPAs) are usually challenged by local people, mainly because of insufficient involvement by stakeholders in the process of designing these MPAs. By incorporating socioeconomic costs into conservation prioritization, scientists can better refine the priority areas and design practical MPAs.

What are the data sources?

Given seahorses are generally understudied in published literature, I derived much of the species distribution data from fishers’ knowledge, divers’ observations, and museum collections. This work was done through field surveys, lab-based data mining, emailing, etc. I also used data from our own Citizen Science initiative –, which attracts global divers to report their sightings of seahorses. To obtain data related to threats, I collected open-access threat data online and filtered them to fit seahorses. These threats include trawling strength, water pollution, and many other habitat-related activities. 

What are my expected outputs?

I will generate priority maps for conservation and management for seahorse species - both at the global scale and for a specific region (i.e. China’s seas). The conservation priorities will inform managers where strict managements (e.g. prohibiting demersal non-selective fishing) are needed and would gain compliance from local fishers. The management priorities will tell us where multiple uses are allowed but managers should try to mitigate human pressures and may also provide alternative habitats (e.g. permanent artificial habitats).

China Context

China has a large marine territory (~ 3.3 million km²) that supports diverse marine species and 1/5 of the global fisheries production. 22,629 species belonging to 46 phyla have been recorded so far. Along with many other marine species, seahorses are highly valued and broadly used by Chinese people. China has exploited seahorses and used them in its traditional medicine for more than 2,000 years. Now China is considered to be the largest consumer of dried seahorses - with an annual demand of 500 t. My study has shown that there are at least five seahorse species living in China’s coastal waters, with very different habitat preferences among species. But they are all facing high pressures from non-selective fishing, e.g., bottom trawlers. We have initiated conservation outreach among local citizens and governments, with an aim to raise the awareness of seahorses. But there is still a long way to go.

Blog posts

Images from the field


My publications 

Zhang, X. and A.C.J. Vincent. 2017. Integrating multiple data sets with species distribution models to inform conservation of the poorly-recorded Chinese seahorses. Biological Conservation 211: 161-171.

Zhang, X. and A.C.J. Vincent. 2018. Predicting distributions, habitat preferences and associated conservation implications for a genus of rare fishes, seahorses. Diversity and distributions


Further reading

Crain, C. M., K. Kroeker, and B. S. Halpern. 2008. Interactive and cumulative effects of multiple human stressors in marine systems. Ecology letters 11:1304-1315.

Davidson, A. D., A. G. Boyer, H. Kim, S. Pompa-Mansilla, M. J. Hamilton, D. P. Costa, G. Ceballos, and J. H. Brown. 2012. Drivers and hot spots of extinction risk in marine mammals. Proceedings of the National Academy of Sciences 109:3395-3400.

Dickinson, J. L., B. Zuckerberg, and D. N. Bonter. 2010. Citizen science as an ecological research tool: challenges
and benefits. Annual review of ecology, evolution, and systematics 41:149-172.

Foster, S. and A. Vincent. 2004. Life history and ecology of seahorses: implications for conservation and management. Journal of Fish Biology 65:1-61.

Franklin, J. 2009. Mapping species distributions: spatial inference and prediction. Cambridge University Press.

Geselbracht, L., R. Torres, G. S. Cumming, D. Dorfman, M. Beck, and D. Shaw. 2009. Identification of a spatially efficient portfolio of priority conservation sites in marine and estuarine areas of Florida. Aquatic Conservation: Marine and Freshwater Ecosystems 19:408-420.

Halpern, B. S., S. Walbridge, K. A. Selkoe, C. V. Kappel, F. Micheli, C. D'Agrosa, J. F. Bruno, K. S. Casey, C. Ebert, and H. E. Fox. 2008. A global map of human impact on marine ecosystems. Science 319:948-952.

Liu, J. 2013. Status of marine biodiversity of the China Seas. PLOS ONE 8:e50719.

Phillips, S. J., R. P. Anderson, and R. E. Schapire. 2006. Maximum entropy modeling of species geographic distributions. Ecological Modelling 190:231-259.

Selig, E. R., W. R. Turner, S. Troëng, B. P. Wallace, B. S. Halpern, K. Kaschner, B. G. Lascelles, K. E. Carpenter, and R. A. Mittermeier. 2014. Global Priorities for Marine Biodiversity Conservation. PLOS ONE 9:e82898.

Shen, G. and M. Heino. 2014. An overview of marine fisheries management in China. Marine Policy 44:265-272.