This volume constitutes a series of invited chapters based on presentations given at an International Conference on the Sensory Biology of Aquatic Animals held June 24-28, 1985 at the Mote Marine Laboratory in Sarasota, Florida. The immediate purpose of the conference was to spark an exchange of ideas, concepts, and techniques among investigators concerned with the different sensory modalities employed by a wide variety of animal species in extracting information from the aquatic environment. By necessity, most investigators of sensory biology are specialists in one sensory system: different stimulus modalities require different methods of stimulus control and, generally, different animal models. Yet, it is clear that all sensory systems have principles in common, such as stimulus filtering by peripheral structures, tuning of receptor cells, signal-to-noise ratios, adaption and disadaptation, and effective dynamic range. Other features, such as hormonal and efferent neural control, circadian reorganization, and receptor recycling are known in some and not in other senses. The conference afforded an increased awareness of new discoveries in other sensory systems that has effectively inspired a fresh look by the various participants at their own area of specialization to see whether or not similar principles apply. This inspiration was found not only in theoretical issues, but equally in techniques and methods of approach. The myopy of sensory specialization was broken in one unexpected way by showing limitations of individual sense organs and their integration within each organism. For instance, studying vision, one generally chooses a visual animal as a model.

Detailed Chapter Contents.- I. Physical and Chemical Characteristics of Signals in the Aquatic Environment.- 1 The Molecular Nature of Chemical Stimuli in the Aquatic Environment.- The Identity of Chemical Stimulants of Behavior.- Stimulants of Feeding Behavior.- Deterrents of Feeding Behavior.- Substances Evoking Predator Avoidance and Alarm Responses.- Sex Attractants.- Substances Influencing Habitat Selection by Larvae.- Similarities Between External Chemical Signals and Internal Neuroactive Agents.- Summary.- 2 Distribution of Chemical Stimuli.- General Problem in Chemoreception.- Historic Perspective.- Spatial and Temporal Frequency Filtering.- Aquatic Stimulus Dispersal.- Physical Transport Processes.- Physiological and Behavioral Time Scales of Chemical Sampling.- Diffusion-Dominated Stimulus Dispersal.- "Micropatches".- Oceanic Bacteria and Nutrient Uptake.- Algal Gametes.- Viscous Flow Fields.- Copepod Feeding Current.- Chemoreceptor Organs.- Turbulent Dispersal.- Turbulence and Chemoreception.- Gypsy Moth and Tsetse Fly.- Orientation in Patchy Odor Field.- Oceanic Fine Structure and Pancake Theory of Fish Orientation.- Information Currents.- Lobster Information Currents.- Conclusion and Summary.- 3 Light and Vision in the Aquatic Environment.- Light in the Sea.- Spectral Transmission of Water.- The Scattering of Light.- Surface Refractive Effects.- Radiance Distribution.- Image Transmission.- Photons and Retinal Image.- The Probability of Photon Capture.- The Brightness of Retinal Image.- Integration Area.- Integration Time.- Visual Noise.- Visual Pigments.- Paired Pigment System.- Visual Pigments and Sensitivity.- Visual Pigments and Visual Performance.- Color Vision.- Conclusions.- 4 Hydrodynamic and Acoustic Field Detection.- Spatial Analysis.- Monopole Sources.- Monopole-Field Equations.- Dipole Sources.- Dipole-Field Equations.- Directional Analysis.- Quadrupole and Higher-Order Moments.- Acoustic-Field Detection.- Hydrodynamic-Field Detection.- Source-Localization Algorithms.- Frequency Analysis.- A Frequency-Response Dilemma.- Old Mistakes and New Solutions.- Physics of Lateral-Line and Inner-Ear Sense Organs.- The Macula Neglecta.- The Boundary Layer Revisited.- Summary.- 5 Underwater Sound as a Biological Stimulus.- The Nature of Sound.- Governing Equations.- Plane Waves.- Spherical Waves.- Pressure-Velocity Ratios.- The Microvar.- Adequate Stimulus.- The Nature of the Coupling Between the Otolith and Cilia.- The Response of Hair Cells Without the Otolith.- Directional Cues.- Ambient Noise.- Underwater Sound Propagation.- Reflection.- Scattering.- Refraction.- Shallow Water Propagation.- Differences Between Underwater and Atmospheric Sound.- Summary.- 6 Detection of Weak Electric Fields.- Electric Fields in Natural Waters.- The Discovery of Bioelectric Fields.- The Origin of Bioelectric Fields.- The Representation of Bioelectric Fields.- Environmental Electric Fields.- Fields Induced by the Recipient Animal.- Behavioral Responses to Weak Electric Fields.- A New Sensory Modality Revealed.- Prey Detection, Sensitivity, and Frequency Response.- Orientation to Environmental Fields.- Detection of the Earth's Magnetic Field.- Physics of Peripheral Sensory Apparatus.- Resistivity of the External Medium.- Potential Distribution Within the Animal.- Differential Operation and Common-Mode Rejection.- Physical Properties of Ampullary Canals.- Sensory Transduction and Nerve Coding.- Electroreceptor Mechanisms.- Detection of Temporal Field Characteristics.- Detection of Spatial Field Characteristics.- Sensory Mechanisms and Central Processing.- A Prey-Detection Algorithm.- Central Processing.- Summary.- II. Behavior: Survival Functions and Stimulus Acquisition.- 7 Behavioral Ecology and Sensory Biology.- Discriminating Food from Nonfood Items.- Food: Which Food Types Should be Eaten?.- How to Avoid Being Eaten.- With Whom to Mate?.- Social Relations.- Summary and Conclusions.- 8 Sensory Performance, Behavior, and Ecology of Fish.- Thresholds.- "Noise".- Directional Perception.- Light.- Sound.- Chemicals.- The Enhancement of Sensory Awareness.- Multiple Stimulation.- Summary and Conclusions.- 9 Social Communication in the Aquatic Environment.- What Is Communication?.- Specialized Communication Sensors.- Special Problems of Communication in Aquatic Environments.- Speed of Signal Propagation.- Active Space.- Signal Attenuation Due to Geometrical Spreading, Absorption, and Scattering.- Background Noise and Receptor Sensitivity.- Signal Source Localization.- Electrical and Acoustic Communication in Mormyrid Fish.- Signal Range.- Acoustic Signalling in Pollimyrus isidori.- Audition in Mormyrids.- Nature of Electrical Signalling in Mormyrids.- Localization of Electric Signals by Mormyrids.- Signaller Identification and Signal Recognition.- Summary.- 10 The Comparative Neurology of Expectation: Stimulus Acquisition and Neurobiology of Anticipated and Unanticipated Input.- Stimulus Acquisition in Electroreception.- Plastic Corollary Discharge.- Efference Copy vs. Corollary Discharge.- Spike and Wave Signs of Central Expectation and Fluctuations of Readiness.- Fluctuations in the Expectation of Input.- Strategies for New Research.- Summary.- III. Signal Extraction: Receptor Cells and Sensory Systems.- III. A. Chemoreception.- 11 The Diversity of Chemoreceptors.- Behavioral Diversity.- Functional Diversity.- Generalists and Specialists.- Dynamic or Static Endings.- Internal and External Detection.- Structural Diversity.- Organ Systems.- Exposed or Protected Detectors.- Few or Many?.- Cilia.- Biochemical Structure.- Olfaction and Taste: Is There a Distinction?.- Proposed Definitions.- Diversity of Stimulatory Substances.- Numbers and Location of Receptors.- Sensory Cilium.- Crustacean Chemoreceptors.- Aesthetasc Hairs.- Esophageal Chemoreceptor in Homarus.- Funnel Canals in Dactyls of Decapod Crustacea.- Hedgehog Hairs.- Dorsal Organ of Decapod Larvae.- Conclusion.- Summary.- 12 Peripheral Filters and Chemoreceptor Cells in Fishes.- Olfactory Organ and Receptor Cell Distribution.- Taste Bud Anatomy and Distribution.- Receptor Mechanisms.- Sensitivity and Specificity to Amino Acids.- "Peripheral Filters": Transduction Processes and Receptor Site Types.- Effects …