Anne with the model cormorant used to test the anti-predator response of piranhas.

Evolution of adaptive variation in fish communities; antipredator behaviour; speciation; species diversity and conservation of freshwater fish in the neotropics (Brazilian Amazon, Mexico and Trinidad) and UK.

Upper Aripo River, Trinidad

Much of my group's work is on the Trinidadian guppy, Poecilia reticulata, a species that has become a model system for investigating evolution in action. We are examining the evolution of reproductive isolation between fish in the Caroni and Oropouche drainages in Trinidad. These river systems have been separated for 1-2 million years. Although the guppies in them can still interbreed if given the opportunity, some post-mating reproductive barriers are already evident. For example, sperm from the female's own river system outcompete foreign sperm, and hybrid offspring formed when guppies from the two drainages are crossed are less viable than pure-bred fish. This research is being done with Anna Ludlow and Stephen Russell.

Northern Range, Trinidad.

Other investigations using the guppy concern aspects of mating behaviour (with Kit Magellan), the effect of thermal regime on behaviour and development (with Lars Pettersson), mutiple mating (with Alfredo Ojanguren) and interactions between guppies and their sister species Poecilia picta (with Indar Ramnarine of the University of the West Indies) .

Anne and Helder tagging piranhas prior to release back to the wild.

I am also interested in the evolution of schooling behaviour. Helder Queiroz (of the Mamirau· Sustainable Development Institute) and I are studying red-bellied piranhas, Pygocentrus nattereri, in the flooded forests of the Brazilian Amazon. Although piranhas are widely depicted as vicious, pack-hunting predators, in fact they are themselves preyed upon by river dolphins, caiman, piscivorous fish such as the pirarucu, and fish-eating birds including cormorants. Our work is showing that piranhas school as a defence against predation.
 

Esox lucius

In the UK I collaborate with Si‰n Grffiths (University of Cardiff), John Armstrong (FRS, Pitlochry) and Alfredo Ojanguren in a project on individual recognition and the benefits of associations between familiar groups of fish. We are using the European minnow, Phoxinus phoxinus, to test our ideas. The work is taking place in the artificial stream system at the Almondbank, FRS laboratory. A second project (with Lorraine Hawkins and John Armstrong) based at Almondbank is examining behavioural interactions between salmon, Salmo salar, and pike, Esox lucius - one of their most important natural predators.

My longstanding interest in the measurement of biological diversity and the structure of ecological assemblages is reflected in the recent publication of my book Measuring Biological Diversity.In addition, Peter Henderson (Pisces Conservation Ltd) and I are exploring changes in species abundance distributions over time.

Sigmoid display by male guppy.

Finally, I am interested in the conservation of biological diversity, particularly of freshwater fish assemblages. Constantino MacÌas Garcia (UNAM) and I are beginning to quantify the impact of introduced poeciliids on endangered fish in Mexico. I am continuing to investigate the biodiversity of freshwater assemblages in Trinidad with my colleagues there. Anuradha Bhat has recently joined the group. Her research is on fish assemblages in the Western Ghats region of India, one of the world's biodiversity hotspots. This will open up new challenges in biodiversity conservation.