Marine Mussels. Elizabeth Gosling

      Preface

      A comprehensive review of the literature on marine mussels was published in 1976,¹ but by the early 1990s a wealth of additional material had appeared, not just in the traditional areas of investigation, but also in the newer fields of nutrition, environmental monitoring, population genetics, toxicology, disease and public health. In view of this, in 1992 I edited a thorough compilation of information on mussels in the form of critical review papers by leading authorities,² titled The Mussel Mytilus. I was also the author of two of the chapters: ‘Systematics and geographic distribution of Mytilus’ and ‘Genetics of Mytilus’, reviewing not just population genetics but cytogenetics and selective breeding studies. The book, with an extensive bibliography of more than 2000 references, is still considered the standard reference text on Mytilus. Although out of print, it continues to have a reasonably good citation rate. For example, individual chapters have citations ranging from 47 to 744, with a total of 2404 citations for the complete volume (Google Scholar, December 2020).

      Subsequently, I wrote Bivalve Molluscs,³ a comprehensive book covering all major aspects of this important class of invertebrates, which was published by Blackwell Publishing UK in 2003. It was well received by reviewers and did well in terms of sales, and in 2011 I was invited by Wiley Blackwell to prepare a second edition, Marine Bivalve Molluscs,⁴ which was published in June 2015. Work on these two volumes entailed a large amount of reading in diverse fields, including biology, ecology, physiology, genetics, culture, disease and public health – an experience that proved invaluable in the preparation of this new volume on marine mussels.

It is now almost 30 years since I edited The Mussel Mytilus. In the interim, there have been many significant advances, along with the emergence of new areas of research in marine mussels, one reason for which is the range of new techniques being applied in their biology and ecology. For example, DNA genetic markers play an increasingly important role in disease diagnosis, detection of different strains of pathogenic bacteria (Chapter 11), identification and tagging of larvae (Chapter 5) and the completely new area of bivalve genomics (Chapter 9). Also, isotope ratios and fatty acid signatures are being used to identify dietary food sources in bivalves, while measurements of stable oxygen isotopes in fossil and contemporary bivalve shells are allowing reconstruction of past sea surface temperatures. Trace elemental fingerprinting, based on naturally occurring elements in bivalve shells, is being used to assess larval origins and trajectories, while fluorescence in situ hybridisation (FISH) combined with cell sorting can identify and rapidly count and sort larvae of several bivalve species in diverse plankton samples. Immunosensors – devices that use specific biochemical reactions mediated by antibodies to detect chemical compounds – may soon replace liquid chromatography, which has long been the official method for detection and quantification of algal toxins in bivalves (Chapter 12). Also, a wide range of molecular biomarkers are increasingly being used to identify exposure to certain chemicals, provide information on spatial and temporal changes in the concentration of contaminants and indicate environmental quality or occurrence of adverse ecological consequences (Chapter 8). Another significant development has been the increasing use of sophisticated mathematical models to describe and predict growth and bioenergetics of individual animals, to track larval movement and recruitment, to study contaminant bioaccumulation in marine bivalves and to predict geographic range of species in global warming scenarios (Chapters 3, 4, 6 and 8). Models are being employed to describe carrying capacity and environmental effects in mussel culture areas (Chapter 10) and to simulate disease and forecast outbreaks (Chapters 11 and 12). Another area that has changed is the management of culture systems, where the emphasis is now more on the use of legislation and control measures, particularly in Europe, North America, Australia and New Zealand (Chapter 10). This also pertains to the control of diseases in bivalves and to hygiene standards for shellfish and shellfish waters.

      This volume does not focus solely on marine mussels in the genus Mytilus but also incorporates research on other commercially important marine genera such as Perna, Aulacomya and Choromytilus, as well as noncommercial genera such as Modiolus, Geukensia, Brachidontes and hydrothermal vent Bathymodiolus species. It therefore has a broader scope and content than The Mussel Mytilus and consequently should not be regarded as a second edition.

Chapter 1 covers the phylogeny and evolution of the Bivalvia and Mytilida. Chapter 2 provides a detailed description of external and internal anatomy. Chapter 3 describes global and local distribution patterns and the physical and biological factors influencing marine mussel distribution and abundance, with a section on climate change and the actual and potential impacts of global warming, ocean acidification and hypoxia on marine mussels. Chapter 4 covers factors influencing filter feeding, together with dietary components and assimilation efficiency, and presents new material on the impacts of mussels on marine ecosystems. Chapter 5 deals with reproduction, larval development and settlement, and has new sections on sperm–egg interaction, larval dispersal, connectivity, identification and abundance estimates. Chapter 6 covers methods of measuring growth, the mussel shell as a marine archive and exogenous and endogenous modulators of growth. The processes of circulation, respiration, excretion and osmoregulation are described in Chapter 7, while Chapter 8 covers types and levels of contaminants in the marine environment, contaminant absorption and assimilation, kinetic modelling, mussel monitoring programmes and biomarkers of pollution. Chapter