N
NEKTON BEHAVIORAL ECOLOGY
Dennis M. Allen
Baruch Marine Field Laboratory, University of South
Carolina, Georgetown, SC, USA
Definition
Nekton refers to mobile organisms which are able to swim
or otherwise move independently of all but the strongest
water currents; the term usually refers to fishes, shrimps,
crabs, and squids, regardless of whether they are slowmoving epibenthic or faster swimming pelagic organisms.
Marine mammals and turtles are sometimes considered
nekton.
Behavioral ecology is the study of the behavior that
underlies the organization, distribution, and ecology of
populations and communities of fishes and motile
macroinvertebrates in estuaries. This deviates somewhat
from definitions that focus on the evolutionary basis for
behavior and the consequences of behavior for the fitness
of organisms.
Introduction
Estuarine nekton assemblages are both spatially and
temporally diverse, largely because of the variation
and the variability in geomorphological, hydrological,
and environmental characteristics of coastal systems.
Central to the well-being of estuarine nekton is their
ability to make physiological adjustments and to move
toward more suitable environmental conditions. Both
responses are usually involved in the selection and
occupation of habitat for feeding, reproduction, and refuge
from predators.
Senses underlying behavioral responses
Sensory modalities such as taste, smell, sight, hearing, and
touch determine the activities of nekton. The importance
of the various senses differs among species and often
among life stages of the same species (Kotrschal, 1999).
Fishes with limited capacity to move far or fast tend to
be thigmotactic and cryptic and have high fidelity and a
relatively small home range. Blennies, gobies, and other
demersal fishes can learn the topography of an area and
even return to it if displaced (Gibson, 1999). Other fishes
have well-developed senses of chemical and sound
detection which enable them to locate food, mates, and
natal spawning areas over long distances. Insights into
the reproductive behavior of fishes have come from the
study of sound production and the use of passive acoustic
technology. Field studies have revealed locations, timing,
and factors influencing the aggregation of estuarine fishes
(especially members of the drum family) for spawning,
and this information has been useful to fisheries management. Vision is particularly important to predacious fishes.
Differences in food preferences, foraging time, and
capture behavior enable many species to co-occur within
habitats. Differences in physiological tolerances, sensitivity, and mobility enable species to exploit the full range of
estuarine habitats and environmental conditions.
Movement
Movement is a primary manifestation of nekton behavior.
It is necessary for procuring food, growth, survival, and
completing life cycles. Understanding the behavior of
nekton is essential to understanding the ecology of individuals, populations, and communities as well as the roles
nekton play in ecosystem function. For example, life history strategies vary widely for estuarine nekton with many
species undergoing major ontogenetic shifts in motility,
M.J. Kennish (ed.), Encyclopedia of Estuaries, DOI 10.1007/978-94-017-8801-4,
© Springer Science+Business Media Dordrecht 2016
NEKTON BEHAVIORAL ECOLOGY
Dennis M. Allen
Baruch Marine Field Laboratory, University of South
Carolina, Georgetown, SC, USA
Definition
Nekton refers to mobile organisms which are able to swim
or otherwise move independently of all but the strongest
water currents; the term usually refers to fishes, shrimps,
crabs, and squids, regardless of whether they are slowmoving epibenthic or faster swimming pelagic organisms.
Marine mammals and turtles are sometimes considered
nekton.
Behavioral ecology is the study of the behavior that
underlies the organization, distribution, and ecology of
populations and communities of fishes and motile
macroinvertebrates in estuaries. This deviates somewhat
from definitions that focus on the evolutionary basis for
behavior and the consequences of behavior for the fitness
of organisms.
Introduction
Estuarine nekton assemblages are both spatially and
temporally diverse, largely because of the variation
and the variability in geomorphological, hydrological,
and environmental characteristics of coastal systems.
Central to the well-being of estuarine nekton is their
ability to make physiological adjustments and to move
toward more suitable environmental conditions. Both
responses are usually involved in the selection and
occupation of habitat for feeding, reproduction, and refuge
from predators.
Senses underlying behavioral responses
Sensory modalities such as taste, smell, sight, hearing, and
touch determine the activities of nekton. The importance
of the various senses differs among species and often
among life stages of the same species (Kotrschal, 1999).
Fishes with limited capacity to move far or fast tend to
be thigmotactic and cryptic and have high fidelity and a
relatively small home range. Blennies, gobies, and other
demersal fishes can learn the topography of an area and
even return to it if displaced (Gibson, 1999). Other fishes
have well-developed senses of chemical and sound
detection which enable them to locate food, mates, and
natal spawning areas over long distances. Insights into
the reproductive behavior of fishes have come from the
study of sound production and the use of passive acoustic
technology. Field studies have revealed locations, timing,
and factors influencing the aggregation of estuarine fishes
(especially members of the drum family) for spawning,
and this information has been useful to fisheries management. Vision is particularly important to predacious fishes.
Differences in food preferences, foraging time, and
capture behavior enable many species to co-occur within
habitats. Differences in physiological tolerances, sensitivity, and mobility enable species to exploit the full range of
estuarine habitats and environmental conditions.
Movement
Movement is a primary manifestation of nekton behavior.
It is necessary for procuring food, growth, survival, and
completing life cycles. Understanding the behavior of
nekton is essential to understanding the ecology of individuals, populations, and communities as well as the roles
nekton play in ecosystem function. For example, life history strategies vary widely for estuarine nekton with many
species undergoing major ontogenetic shifts in motility,
M.J. Kennish (ed.), Encyclopedia of Estuaries, DOI 10.1007/978-94-017-8801-4,
© Springer Science+Business Media Dordrecht 2016