7
Ecological Role of Lipids in the Health
and Success of Fish Populations
S. Marshall Adams
7.1. Introduction
The health or fitness of fish populations in aquatic ecosystems can be assessed by
a variety of criteria ranging from individual biochemical and physiological measures to population level attributes such as growth, reproductive success, or yearclass strength. Lipid storage and dynamics within the organism, however, are a
particular important attribute of fish health and future population success. Lipids
are critical not only to the survival and fitness of individuals but also to the success
of reproduction and recruitment of future year classes within the population. This
chapter discusses four areas in which lipids play an important role in fish health
including (1) overwinter starvation and survival, (2) energy allocation strategies,
(3) reproductive performance and early life history, and (4) environmental stress.
The primary purpose of this chapter is to evaluate and discuss the importance of
the energetic lipids (triacylglycerols [TAG]) from an ecological perspective, with
less emphasis on the more specific biochemical aspects of lipid dynamics in fish
such as the role of fatty acids and lipid classes in fish health. These latter aspects
of fish lipid dynamics are usually more related to feeding and nutritional aspects,
which are presented in a variety of publications that address these specific areas
including Halver (1989), Henderson and Tocher (1987), Cowey et al. (1985), and
Love (1980). Furthermore, the purpose of this chapter is not to provide an exhaustive coverage of the literature relative to the ecological role of lipids in fish health
but to give representative examples that illustrate the many and diverse ways that
lipids are important in regulating and maintaining population stability and overall
fitness of fish. Even though the objective of this book is to address the role of
lipids in freshwater organisms, much of what we understand about the importance
of lipids in fish comes from marine studies. Therefore, in areas where information
is generally lacking for freshwater fish, discussions are supplemented with examples from marine systems that are relevant to freshwater environments. Reproductive development and early life history, lipid cycling, and energy allocation are the
primary areas where studies of marine fish appear to be more complete compared
with freshwater species.
132
Ecological Role of Lipids in the Health
and Success of Fish Populations
S. Marshall Adams
7.1. Introduction
The health or fitness of fish populations in aquatic ecosystems can be assessed by
a variety of criteria ranging from individual biochemical and physiological measures to population level attributes such as growth, reproductive success, or yearclass strength. Lipid storage and dynamics within the organism, however, are a
particular important attribute of fish health and future population success. Lipids
are critical not only to the survival and fitness of individuals but also to the success
of reproduction and recruitment of future year classes within the population. This
chapter discusses four areas in which lipids play an important role in fish health
including (1) overwinter starvation and survival, (2) energy allocation strategies,
(3) reproductive performance and early life history, and (4) environmental stress.
The primary purpose of this chapter is to evaluate and discuss the importance of
the energetic lipids (triacylglycerols [TAG]) from an ecological perspective, with
less emphasis on the more specific biochemical aspects of lipid dynamics in fish
such as the role of fatty acids and lipid classes in fish health. These latter aspects
of fish lipid dynamics are usually more related to feeding and nutritional aspects,
which are presented in a variety of publications that address these specific areas
including Halver (1989), Henderson and Tocher (1987), Cowey et al. (1985), and
Love (1980). Furthermore, the purpose of this chapter is not to provide an exhaustive coverage of the literature relative to the ecological role of lipids in fish health
but to give representative examples that illustrate the many and diverse ways that
lipids are important in regulating and maintaining population stability and overall
fitness of fish. Even though the objective of this book is to address the role of
lipids in freshwater organisms, much of what we understand about the importance
of lipids in fish comes from marine studies. Therefore, in areas where information
is generally lacking for freshwater fish, discussions are supplemented with examples from marine systems that are relevant to freshwater environments. Reproductive development and early life history, lipid cycling, and energy allocation are the
primary areas where studies of marine fish appear to be more complete compared
with freshwater species.
132