Callum Roberts



Professor Callum Roberts is a marine conservation biologist in the Department of Environment and Geography. He was first tempted into marine science by a trip to the coral reefs of Saudi Arabia, where he studied behaviour and coexistence of herbivorous fishes. This led to a lifelong love of coral reefs and effectively dispelled his prior notion that marine science was all about freezing on the deck of a North Sea trawler knee deep in fish. In the early 1990s his interests in behaviour gave way to concern about the deteriorating condition of coral reefs, leading to his current emphasis on marine conservation. He has recently worked on the BBC TV programme Blue Planet, appearing in the last episode, and was a series scientific adviser to Blue Planet II.

Currently, Callum's research focuses on human impacts on marine ecosystems. While his interests in marine conservation have blossomed over the years, his field research remains firmly rooted on coral reefs. On the islands of St. Lucia and Saba in the Caribbean, he has studied the effects of marine reserves closed to all fishing. Those studies revealed both the huge scale of human impacts on the sea, and the means of protecting marine ecosystems from such effects. He is now working to gain acceptance for marine reserves more widely, including in Britain and Europe where he is helping fishers to promote the concept within the industry and to politicians.

Callum has served on a US National Research Council Committee on Marine Protected Areas and has also been a member of the Marine Reserves Working Group, headed up by Jane Lubchenco, Steve Gaines and Steve Palumbi at the National Center for Ecological Analysis and Synthesis in Santa Barbara. With this group he sought to develop a more robust theoretical underpinning for the design and implementation of marine reserves.

In parallel with work on reserves, Callum has also been very active with the Coral Reef Fish Specialist Group of the World Conservation Union (IUCN). Working with many colleagues inside and out of this group, he has developed global maps of the biodiversity distribution of reef fishes and other faunal groups. These maps have revealed that marine species are more at risk of global extinction than previously believed. Many have small geographic ranges and life history characteristics that render them vulnerable to extinction. However, the maps also show ways to prioritise conservation investment into areas where those resources could be most effective.

He was awarded a Pew Fellowship in Marine Conservation in 2000 to tackle obstacles to implementing marine reserves, and in 2001 he was awarded a Hardy Fellowship in Conservation Biology at Harvard University.



Use of marine reserves as tools for biodiversity conservation/fishery management

I have been studying the function and theory of marine reserves since 1991. During this time I have been a member of two groups working to develop a theory of reserves, synthesise what is known about them and identify what we still need to find out. The Marine Reserves Working Group at the National Center for Ecological Analysis and Synthesis (headed by Jane Luchenco, Steve Palumbi and Steve Gaines) is primarily concerned with developing the theory, while the U.S. National Research Council Committee on Evaluation, Design and Monitoring of Marine Reserves is mainly charged with synthesizing information and identifying research priorities. Work with these groups is helping to push forward both the science of reserves, and the prospects for implementing them.

My field studies of reserves centred on two Caribbean islands: Saba and St. Lucia. Since 1991 I have been making annual censuses of reef fish and coral communities around the island of Saba to examine the efficacy of a marine reserve and broader coastal management initiatives there. In St. Lucia, since 1994 I have been undertaking a long term study of a wonderful system of reserves. In 1995, St. Lucia embarked upon an ambitious coastal management program to rehabilitate its severely overexploited reef fisheries, and reduce conflicts between fishing and the developing tourism industry. Fully-protected marine reserves lie at the heart of this program. The reserves are intended to reverse the effects of overfishing, supplement fisheries, increase biodiversity and recover more natural ecosystem functioning. Fishery support is expected to be achieved through build-up of spawning stock and spillover to adjacent fisheries, while larger fish stocks and improved reef condition will attract tourists. Four reserves were established over an 11km stretch of coast and are interspersed with fishing areas in a zonation plan called the Soufriere Marine Management Area. Compliance with no-take regulations has been high. Following reserve creation we have documented an extraordinarily rapid increase in biomass of commercially important reef fishes. In just over three years this has tripled inside reserves. More importantly, biomass has doubled in fishing grounds. One reason for the quick response in fishing grounds may be due to the large area that has been protected. In this case, 35% of coral reefs were protected, a much greater proportion of fishing grounds than is usual.

Since 1995, I have also been collaborating with some gifted modellers (biologists and economists - Josh Sladek Nowlis, Jack Pezzey and Lynda Rodwell) to examine questions about reserve performance. These models are now being used to develop guidance on reserve design and are generating exciting new predictions about their function.

Extinction risk in the sea

I have completed a study of the risk of extinction to marine species, together with my wife and research associate, Julie Hawkins, and a team of enthusiastic graduate students. The results are described elsewhere (see Research Grants section).

Impacts of fishing on coral reefs at population and ecosystem levels

Work on the effects of fishing on marine ecosystems has largely been a spin-off from my reserve studies. However, the alarming region-wide biodiversity losses I have documented have fuelled my efforts to search for better conservation tools for the marine environment.

Global distribution of coral reef biodiversity and definition of conservation priorities

My wife, Julie Hawkins, and I created a global database of coral reef fish biodiversity, in collaboration with members of the IUCN Coral Reef Fish Specialist Group, Chaired by Dr Don McAllister (Ocean Voice International) and Patty Almada-Villela. The project advanced understanding of the global patterns and determinants of marine biological diversity and provided urgently needed information to establish and guide conservation priorities for the tropical marine environment.

Impacts of pollution on coral reefs

In 1995 Josh Sladek Nowlis and I, together with collaborators in St. Lucia, made a study of the impact of sediment deposited on St. Lucian coral reefs by a tropical storm. I have since extended this study, in collaboration with several students (Maggy Nugues, Chris Schelten and Tessa McGarry) to look at the processes by which sedimentation degrades reefs and the extent to which it is undermining coastal management efforts such as the establishment of marine reserves.

Research group(s)


Julie P. Hawkins (Research Associate). Working on impacts of recreational scuba diving on coral reefs, effects of marine reserves in St. Lucia, effects of fishing on coral reef fish communities, and global biodiversity distribution of reef fishes.


Chris Schelten (2003) (Post-doctoral research associate). Effects of pollution on the early life history of corals.

Fiona Gell (2001-2003) (Post-doctoral research associate). Working on effects of marine reserves on fishery yields in St. Lucia.

Lynda Rodwell (2001-2003) (Post-doctoral research associate). Economics of marine reserves.


2004-2007 Esmée Fairbairn Foundation £159,950 Towards a network of marine protected areas in the British Isles
2000-2004 Conservation International $20,000 Hotspots, endemism and the conservation of marine biodiversity. Co-investigators (in York) Julie Hawkins and Colin McLean.
2000-2003 Department for International Development, UK. In collaboration with Marine Resources Assessment Group, Imperial College, London £302,287; York share £150,000 Impact and amelioration of sediment and agro-chemical pollution in Caribbean coastal waters
Pew Fellowship in Marine Conservation
Challenging problems surrounding the use of marine reserves
UK Darwin Initiative for the Survival of Species
Migratory behaviour and population status of whale sharks in Belize, and the role of marine reserves in protecting them. Co-investigators Rachel Graham and Will Heyman.
Natural Environment Research Council
Cascading effects of marine reserve protection, sediment pollution and natural disturbances on St. Lucian coral reefs. Co-investigator Julie Hawkins
Natural Environment Research Council
£35,000 Population structure and migratory behaviour of whale sharks, Rhincodon typus, in Belize. Co-investigators Rachel Graham and Will Heyman.
1999-2000 World Wildlife Fund, Washington, DC
Preparation of an educational resource pack on fully-protected marine reserves to help people working to establish reserves to argue more effectively for them. Co-investigator Julie Hawkins.
Natural Environment Research Council £25,000
Large-scale, long term variation in reef fish community structure.
World Conservation Union Species Survival Commission
Extinction risk in marine species. Co-investigator Julie Hawkins.
Natural Environment Research Council
Ecosystem effects of cessation of fishing in St. Lucian marine reserves. Co-investigator Julie Hawkins.
UK Darwin Initiative
The role of marine reserves in sustaining fisheries and biodiversity on St. Lucian coral reefs. Co-investigator Julie Hawkins.


Leanne Mason (2004 onwards). Conservation priority areas and marine reserve network design in northern Europe. Co-supervised with Colin McClean.

Stephen Mangi (2003 onwards). Effects of Artisanal Fishing Gears on Kenya's Coral Reefs.

Andrea Saenz Arroyo de Los Cobos. (2000-2004). Fisheries and Conservation in the Gulf of California, Mexico.

Rachel Graham (1999-2003). Population dynamics and migratory behaviour of whale sharks.

Nola Barker (1999-2003). Perceptions of coral reefs and impacts of tourists in the Caribbean.

Chris Schelten (1997-2002).  Impacts of sedimentation on recruitment, growth and survival of Caribbean corals.

Lynda Rodwell (1997-2001). Economic benefits of marine reserves in East Africa.

Maggy Nugues (1996-2000). Interactive effects of algal growth and sediment pollution on Caribbean coral reefs.



  • Applied Ecology and Environmental Management (year 2)


  • Marine Ecosystem Management
  • Research Methods
  • The Earth: An Introduction to the Science of the Atmosphere, Crust and Oceans

External activities

Editorial duties

  • 1999-2003. Member of editorial board of Conservation Biology
  • 1997-2000. Member of Editorial board of journal Animal Conservation
  • 1996. Senior editor of the proceedings of a symposium: Marine reserves: Function and Design held at the 8th International Coral Reef Symposium, Panama.
  • 1991-1996. Co-editor of Reef Encounter
Roberts, Callum

Contact details

Prof. Callum Roberts
Department of Environment and Geography
University of York
YO10 5NG

Tel: 01904 324066
Fax: 01904 322998