Peter Matthiessen graduated with honors from Bristol University, UK with a Bachelor of Science degree in Zoology. He received his Ph.D. from London University, Queen Elizabeth College in Zoology. Principal Ecotoxicologist, Ministry of Agriculture, Fisheries and Food (MAFF), Center for Environment Fisheries and Aquatic Science (CEFAS).

Research experience since 1970 has been concerned with the effects of pollutants on aquatic wildlife. Initially, this involved studies of the effects of heavy metals on the physiology of fish, but since 1973, attention has been focused on pesticides. Between 1973 and 1977, laboratory toxicology studies were made of the impact of molluscides, larvicides and insecticides on tropical aquatic organisms, and progress was made towards the development of more target-specific compounds.

Between 1977 and 1985, work was largely field-based in Africa, where studies were made of the environmental impact of the widespread use of DDT and endosulfan on both fish and terrestrial organisms such as birds and bats in remote and inaccessible areas.

In 1983, consultancy work for the Asian Development Bank was carried out in Indonesia. This involved an assessment of the impact of current crop pest control practices on humans and wildlife, and advice on the possible adverse effects of the Indonesian national Crop Protection Project.

Since 1985, employed by the UK Ministry of Agriculture as an ecotoxicologist at CEFAS Burnham-on-Crouch Laboratory and currently Principal Ecotoxicologist.

Research involves field and laboratory studies of the impact of wastes, industrial chemicals and pesticides on aquatic fauna and flora. Advisor to the MAFF Pesticide Safety Directorate, and a member of the Environmental Panel of the Subcommittee on Pesticides (SCP) which in turn is part of the Advisory Committee on Pesticides. In addition, responsible for advice to the Department of Trade and Industry on the environmental effects of chemicals used in the offshore oil and gas industry.

Advisor to a number of international organizations including the Paris Commission, the International Council for Exploration of the Sea, and the European and Mediterranean Plant Protection Organization. Member of the Editorial Board of the international journal Environmental Pollution.