Fish pheromones and related cues (Eds. Sorensen and Wisenden)

Abstract

For many people, the combination of the words ‘fish’ and ‘smell’ has a negative connotation. As defined in the Oxford English Dictionary, ‘smell’ is Ba quality in something that is perceived by the faculty of smell^, andwhen the word ‘fish’ is attached, that quality is an unpleasant one. But for some people, at least in the world of fish biology, their minds jump to a different definition in the OED: Bthe faculty or power of perceiving odours or scents by means of the organs in the nose^. This book will appeal to such people. More specifically, the book focuses on ‘pheromones’, a term that was first coined in 1959 (Karlson and Luscher 1959). The study of pheromones, however, pre-dates the word itself, and can be traced back to at least the 1800’s. The field reached a wider audience within the scientific community in the middle of the 20th century, following Karl Von Frisch’s pioneering studies on communication in honey bees. Von Frisch also documented the release of chemical alarm signals by injured minnows, and this discovery presaged a major focus on pheromone research in the aquatic environment. A cursory look through the book’s reference sections suggests there has been another, more recent surge in studies on fish pheromones over the past two decades. Despite the long history and recent advances in this field, however, the Preface notes that this is the first book of its kind, which puts it in the unique position of being both timely and over-due. The first chapter defines several relevant terms and seeks to create a common framework for the sections that follow. Chief among these terms are those found in the book’s title—‘pheromones’ and ‘related cues’. ‘Pheromones’ are identified as adaptive chemical cues that elicit a specific response in conspecifics. They also communicate information that is shared by all individuals of a species (Sorensen describes them as Banonymous^). ‘Related conspecific cues’, on the other hand, are learned or highly context dependent, and can vary significantly among individuals (they can act as an individual fish’s Bsignature^). The distinction between these two categories is not always clear, however, and the use of these terms in later chapters is not uniform. In one chapter, for example, Wisenden warns that many of the fish ‘pheromones’ currently studied are not truly pheromones (because there is no apparent selective pressure on the sender of the cues), but in the next chapter the term ‘pheromone’ is used for precisely these types of chemicals. This does not detract from the quality of the book’s content, but perhaps indicates a missed opportunity to provide a unified framework for terminology. A main focus early in the book is the species-specific properties of pheromones and their related cues. Sorensen and Baker introduce the term ‘pheromone complexes’, which could be Bmixtures of relatively common metabolic products^ that are combined in different ways to create species-specific pheromones. From an evolutionary standpoint, this might provide a simpler alternative to the adaptation of uniquely specialized pheromones within Environ Biol Fish (2015) 99:169–170 DOI 10.1007/s10641-015-0460-y