Fish bioaccumulation and biomarkers in environmental risk assessment: a review

Beginning with Emlen (1966) and MacArthur and Pianka (1966) and extending through the last ten years, several authors have sought to predict the foraging behavior of animals by means of mathematical models. These models are very similar,in that they all assume that the fitness of a foraging animal is a function of the efficiency of foraging measured in terms of some "currency" (Schoener, 1971) -usually energy- and that natural selection has resulted in animals that forage so as to maximize this fitness. As a result of these similarities, the models have become known as "optimal foraging models"; and the theory that embodies them, "optimal foraging theory." The situations to which optimal foraging theory has been applied, with the exception of a few recent studies, can be divided into the following four categories: (1) choice by an animal of which food types to eat (i.e., optimal diet); (2) choice of which patch type to feed in (i.e., optimal patch choice); (3) optimal allocation of time to different patches; and (4) optimal patterns and speed of movements. In this review we discuss each of these categories separately, dealing with both the theoretical developments and the data that permit tests of the predictions. The review is selective in the sense that we emphasize studies that either develop testable predictions or that attempt to test predictions in a precise quantitative manner. We also discuss what we see to be some of the future developments in the area of optimal foraging theory and how this theory can be related to other areas of biology. Our general conclusion is that the simple models so far formulated are supported are supported reasonably well by available data and that we are optimistic about the value both now and in the future of optimal foraging theory. We argue, however, that these simple models will requre much modification, espicially to deal with situations that either cannot easily be put into one or another of the above four categories or entail currencies more complicated that just energy.

Citation classic - optimal foraging - a selective review of theory and tests

Most empirical and theoretical studies of resource use and population dynamics treat conspecific individuals as ecologically equivalent. This simplification is only justified if interindividual niche variation is rare, weak, or has a trivial effect on ecological processes. This article reviews the incidence, degree, causes, and implications of individual-level niche variation to challenge these simplifications. Evidence for individual specialization is available for 93 species dis- tributed across a broad range of taxonomic groups. Although few studies have quantified the degree to which individuals are specialized relative to their population, between-individual variation can some- times comprise the majority of the population's niche width. The degree of individual specialization varies widely among species and among populations, reflecting a diverse array of physiological, be- havioral, and ecological mechanisms that can generate intrapopu- lation variation. Finally, individual specialization has potentially im- portant ecological, evolutionary, and conservation implications. Theory suggests that niche variation facilitates frequency-dependent interactions that can profoundly affect the population's stability, the amount of intraspecific competition, fitness-function shapes, and the population's capacity to diversify and speciate rapidly. Our collection of case studies suggests that individual specialization is a widespread but underappreciated phenomenon that poses many important but unanswered questions.

/pdf/the-ecology-of-individuals-incidence-and-implications-of-1qvkodaqfy.pdf

The Ecology of Individuals: Incidence and Implications of Individual Specialization

Cortisol is the principal corticosteriod in teleost fishes and its plasma concentrations rise dramatically during stress. The relationship between this cortisol increase and its metabolic consequences are subject to extensive debate. Much of this debate arises from the different responses of the many species used, the diversity of approaches to manipulate cortisol levels, and the sampling techniques and duration. Given the extreme differences in experimental approach, it is not surprising that inconsistencies exist within the literature. This review attempts to delineate common themes on the physiological and metabolic roles of cortisol in teleost fishes and to suggest new approaches that might overcome some of the inconsistencies on the role of this multifaceted hormone. We detail the dynamics of cortisol, especially the exogenous and endogenous factors modulating production, clearance and tissue availability of the hormone. We focus on the mechanisms of action, the biochemical and physiological impact, and the interaction with other hormones so as to provide a conceptual framework for cortisol under resting and/or stressed states. Interpretation of interactions between cortisol and other glucoregulatory hormones is hampered by the absence of adequate hormone quantification, resulting in correlative rather than causal relationships.

Cortisol in teleosts: dynamics, mechanisms of action, and metabolic regulation

 – Among the species in the family Salmonidae, those represented by the genera Salmo, Salvelinus, and Oncorhynchus (subfamily Salmoninae) are the most studied. Here, various aspects of phenotypic and life-history variation of Atlantic salmon Salmo salar L., brown trout Salmo trutta L., and Arctic charr Salvelinus alpinus (L.) are reviewed. While many strategies and tactics are commonly used by these species, there are also differences in their ecology and population dynamics that result in a variety of interesting and diverse topics that are challenging for future research. Atlantic salmon display considerable phenotypic plasticity and variability in life-history characters ranging from fully freshwater resident forms, where females can mature at approximately 10 cm in length, to anadromous populations characterised by 3–5 sea-winter (5SW) salmon. Even within simple 1SW populations, 20 or more spawning life-history types can be identified. Juveniles in freshwater can use both fluvial and lacustrine habitats for rearing, and while most smolts migrate to sea during the spring, fall migrations occur in some populations. At sea, some salmon undertake extensive oceanic migrations while other populations stay within the geographical confines of areas such as the Baltic Sea. At the other extreme are those that reside in estuaries and return to freshwater to spawn after spending only a few months at sea. The review of information on the diversity of life-history forms is related to conservation aspects associated with Atlantic salmon populations and current trends in abundance and survival. Brown trout is indigenous to Europe, North Africa and western Asia, but was introduced into at least 24 countries outside Europe and now has a world-wide distribution. It exploits both fresh and salt waters for feeding and spawning (brackish), and populations are often partially migratory. One part of the population leaves and feeds elsewhere, while another part stays as residents. In large, complex systems, the species is polymorphic with different size morphs in the various parts of the habitat. Brown trout feed close to the surface and near shore, but large individuals may move far offshore. The species exhibits ontogenetic niche shifts partly related to size and partly to developmental rate. They switch when the amount of surplus energy available for growth becomes small with fast growers being younger and smaller fish than slow growers. Brown trout is an opportunistic carnivore, but individuals specialise at least temporarily on particular food items; insect larvae are important for the young in streams, while littoral epibenthos in lakes and fish are most important for large trout. The sexes differ in resource use and size. Females are more inclined than males to become migratory and feed in pelagic waters. Males exploit running water, near-shore and surface waters more than females. Therefore, females feed more on zooplankton and exhibit a more uniform phenotype than males. The Arctic charr is the northernmost freshwater fish on earth, with a circumpolar distribution in the Holarctic that matches the last glaciation. Recent mtDNA studies indicate that there are five phylogeographic lineages (Atlantic, Arctic, Bering, Siberian and Acadian) that may be of Pleistocene origin. Phenotypic expression and ecology are more variable in charr than in most fish. Weights at maturation range from 3 g to 12 kg. Population differences in morphology and coloration are large and can have some genetic basis. Charr live in streams, at sea and in all habitats of oligotrophic lakes, including very deep areas. Ontogenetic habitat shifts between lacustrine habitats are common. The charr feed on all major prey types of streams, lakes and near-shore marine habitats, but has high niche flexibility in competition. Cannibalism is expressed in several cases, and can be important for developing and maintaining bimodal size distributions. Anadromy is found in the northern part of its range and involves about 40, but sometimes more days in the sea. All charr overwinter in freshwater. Partial migration is common, but the degree of anadromy varies greatly among populations. The food at sea includes zooplankton and pelagic fish, but also epibenthos. Polymorphism and sympatric morphs are much studied. As a prominent fish of glaciated lakes, charr is an important species for studying ecological speciation by the combination of field studies and experiments, particularly in the fields of morphometric heterochrony and comparative behaviour.

https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1600-0633.2003.00010.x

Atlantic salmon Salmo salar L., brown trout Salmo trutta L. and Arctic charr Salvelinus alpinus (L.): a review of aspects of their life histories

The previous NRC handbooks covering the nutritional requirements of aquatic animals rapidly achieved the status of standard works of reference, and the same is likely to be the case for Nutrient Requirements of Fish and Shrimp. This new book, which updates and expands upon information given in the 1993 edition, has been put together by a committee of ten well-known aquatic animal nutritionists. Given the length of time that has elapsed since publication of the previous edition, this book is long overdue. The book summarizes current knowledge about nutritional requirements of fish and shrimp (some readers will be more familiar with several species under the name prawns, and some information is also given for other crustaceans). In addition, it provides information about the basic concepts of nutritional research, gives guidelines relating to the design of practical nutritional studies, and introduces some of the basic methods used in such studies. Not surprisingly, given the amount of nutritional information available for the aquatic animal groups considered in this publication, there is greater coverage of finfish than of the shrimps (prawns). Major finfish groups considered are warm-water omnivores (carps, tilapias and catfishes), cold-water carnivores (salmonids) and warm-water marine species, such as sea-basses and sea breams. Among the crustaceans, most of the information given relates to marine penaeids, although there is also some mention of the feeding and nutrition of lobsters, crabs, crayfish, and the giant river prawn, Macrobrachium rosenbergii. The book is made up of a Summary and Introduction, 15 main chapters, an overview of future research needs, a series of summary tables, lists of species names, abbreviations and acronyms, appendices, and an index. The first main chapter introduces basic concepts and methodology and there then follow general overviews of feeding, digestion, and metabolism, before there is a move to considerations of the macronutrients and micronutrients. Feed additives and anti-nutritional factors are also covered, as are methods used to assess nutrient bioavailability, and there are also chapters that cover feeding practices and feed management, and larval nutrition. The closing chapters cover feed ingredients, their processing, and the production of formulated feeds for aquatic species.

National Research Council (NRC): Nutrient requirements of fish and shrimp

The relationship between the temperature requirements of some fish species, using published data for growth optima, final preferences and lethal limits were examined. A good correlation was found and it is suggested that the data established gives a good estimate of the temperature promoting maximum growth. Determinations of final preferenda are easily conducted in the laboratory and could therefore be used to give rapid assessments of optimum growth temperatures of potential culture species. The practical application of such measurements is discussed.

https://www.waterboards.ca.gov/water_issues/programs/tmdl/docs/303d_policydocs/216.pdf

Temperature tolerance and the final preferendum—rapid methods for the assessment of optimum growth temperatures

Following feeding, the rate of oxygen consumption of fishes increases to a peak and then slowly declines to the pre-feeding level. Many factors have been shown to influence the magnitude and duration of post-prandial oxygen consumption and these include quantity and/or quality of ration and environmental temperature. The effects of the various factors are described and the phenomenon of the post-prandial increase in metabolic rate of fish is discussed in relation to work with other species of animals.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1981.tb03780.x

The influences of feeding on the metabolic rate of fishes: a short review

The form and structure of fish otoliths are species specific, allowing them to be used as an aid in identification of prey species consumed by piscivores. Otholith length-fish length relationships can have application in the estimation of the size of fish prey consumed by squid, but, because otoliths are relatively rapidly attacked by acidic solutions, these relationships can not be used routinely for the estimation of the size of fish taken by marine mammals, birds and predatory fishes. Evidence from recent physiological studies of gastrointestinal motility suggests that indigestible material (skeletal fragments and otoliths) would not accumulate in the stomachs of marine mammals and birds, and any otoliths found amongst stomach contents probably represent the remains of a single feeding bout. Thus, the identification and counting of otoliths could provide a quantitative estimate of consumption of numbers of fish within different species. Results of anal)(ses of faecal material may not give accu...

The use and abuse of fish otoliths in studies of feeding habits of marine piscivores

List of Contributors. Preface. Feed Composition and Analysis (Malcolm Jobling). Feed Types, Manufacture and Ingredients (Malcolm Jobling, Emidio Gomes and Jorges Dias). Techniques for Measuring Feed Intake (Malcolm Jobling, Denis Coves, Borge Damsgard, Henrik R. Kristiansen, Juha Koskela, Thuridur E. Petursdottir, Sunil Kadri and Olafur Gudmundsson). Experimental Design in Feeding Experiments (Kari Ruohonen, Juhani Kettunen and Jonathan King). Gustation and Feeding Behaviour (Charles F. Lamb). Environmental Factors and Feed Intake: Mechanisms and Interactions (Patrick Kestemont and Etienne Baras). Environmental Factors and Feed Intake: Rearing Systems (Marie--Laure Begout Anras, Marilyn Beauchaud, Jon--Erik Juell, Deniks Coves and Jean--Paul Lagardere). Feeding Rhythms (Juan Antonio Madrid, Thierry Boujard and F. Javier Sanchez--Vazquez). Feeding Anticipatory Activity (F. Javier Sanchez--Vazquez and Juan Antonio Madrid). Effects of Feeding Time on Feed Intake and Growth (Valerie Bolliet, Mezian Azzaydi and Thierry Boujard). Effects of Nutritional Factors and Feed Characteristics on Feed Intake (Manuel de la Higuera). Regulation of Food Intake by Neuropeptides and Hormones (Nuria de Pedro and Bjorn Thrandur Bjornsson). Physiological Effects of Feeding (Chris Carter, Dominic Houlihan, Anders Kiessling, Francoise Medale and Malcolm Jobling). Feeding Management (Anders Alanara, Sunil Kadri and Mihalis Paspatis). Nutrient Partitioning and the Influence of Feed Composition on Body Composition (Malcolm Jobling). Glossary of Terms. Index

Malcolm Jobling

Papers

National Research Council (NRC): Nutrient requirements of fish and shrimp

Temperature tolerance and the final preferendum—rapid methods for the assessment of optimum growth temperatures

The influences of feeding on the metabolic rate of fishes: a short review

The use and abuse of fish otoliths in studies of feeding habits of marine piscivores

Food intake in fish.