occurring as members of the epibenthic community or as
burrowing infauna. They are one of the most conspicuous
members of the invertebrate fauna inhabiting sandy or
muddy beaches where they burrow into sediments or are
closely associated with seagrass and algal wrack. Amphipods are abundant as fouling organisms on hard substrates
and often numerically dominate the epifauna of seagrasses
and macroalgae. Many species are also commensal with
benthic invertebrates including sponges, ascidians, and
bryozoans. Relatively few species are exclusively
planktonic. While they have no larval stage that disperses
in the water column, benthic amphipods are often highly
mobile and colonize new habitats quickly.
Amphipods display a great diversity of feeding strategies. They include detritivores, suspension feeders, scavengers, predators, herbivores, and parasites (rarely).
Those that process sediments play an important role as
bioturbators in estuaries, altering the physical and chemical conditions, and thus nutrient fluxes, of the sediments. Grazing amphipods in vegetated habitats can
alter the composition of primary producers and play an
important role in limiting the abundance of epiphytes that
can negatively affect seagrass health. Amphipods frequently comprise a large component of the diets of predatory fish and birds and thus play an important role in
the transfer of energy from primary producers to higher
trophic levels.
Due to their short generation times, direct development,
ease of culture, and intimate associations with sediments,
amphipods are routinely used in ecotoxicology as test
organisms for evaluating sediment and water quality and
as biomonitors for environmental contamination.
Bibliography
Burton, G. A., Jr., Denton, D. L., Ho, K., and Ireland, D. S., 2003.
Sediment toxicology testing: issues and methods. In Hoffman,
D. J., Rattner, B. A., Burton, G. A., Jr., and Cairns, J., Jr.
(eds.), Handbook of Ecotoxicology. Boca Raton: CRC Press,
pp. 111–150.
Edgar, G. J., and Shaw, C., 1995. The production and trophic ecology of shallow-water fish assemblages in southern Australia II.
Diets of fishes and trophic relationships between fishes and benthos at Western Port, Victoria. Journal of Experimental Marine
Biology and Ecology, 194, 83–106.
Raffaelli, D. G., 2006. Biodiversity and ecosystem functioning:
issues of scale and trophic complexity. Marine Ecology Progress
Series, 311, 285–294.
Whalen, M. A., Duffy, J. E., and Grace, J. B., 2013. Temporal shifts
in top-down vs. bottom-up control of epiphytic algae in
a seagrass ecosystem. Ecology, 94, 510–520.
Horton, T., Lowry, J., and De Broyer, C., (2013 onwards) World
Amphipoda Database. Accessed at http://www.marinespecies.
org/amphipoda.
ANADROMOUS
Charles A. Simenstad
School of Aquatic and Fishery Sciences, University of
Washington, Seattle, WA, USA
Definition
Organisms such as fishes which hatch in fresh water and
migrate to higher salinities such as the sea to mature and
then migrate back into fresh water to spawn.
Background
Originating in the nineteenth-century Russian literature
and refined from the original term (“contranatant”; Meek,
1916; Subnikov, 1976) by Meyers (1949), anadromous is
one of the three types of migration between the sea and
fresh water (McDowall, 1987). The directed movement
by anadromous fish between these markedly different
habitats is specifically associated with reproductive phases
of their life cycle. Of the approximately 20,000 species of
fish around the world (Cohen, 1970), McDowall estimated
that 54 % are anadromous. They are most common in
northern subpolar and cooler temperate waters.
Amphipods, Figure 1 Grazing amphipods from the family Ampithoidae are abundant in estuarine seagrass beds.
18
ANADROMOUS
burrowing infauna. They are one of the most conspicuous
members of the invertebrate fauna inhabiting sandy or
muddy beaches where they burrow into sediments or are
closely associated with seagrass and algal wrack. Amphipods are abundant as fouling organisms on hard substrates
and often numerically dominate the epifauna of seagrasses
and macroalgae. Many species are also commensal with
benthic invertebrates including sponges, ascidians, and
bryozoans. Relatively few species are exclusively
planktonic. While they have no larval stage that disperses
in the water column, benthic amphipods are often highly
mobile and colonize new habitats quickly.
Amphipods display a great diversity of feeding strategies. They include detritivores, suspension feeders, scavengers, predators, herbivores, and parasites (rarely).
Those that process sediments play an important role as
bioturbators in estuaries, altering the physical and chemical conditions, and thus nutrient fluxes, of the sediments. Grazing amphipods in vegetated habitats can
alter the composition of primary producers and play an
important role in limiting the abundance of epiphytes that
can negatively affect seagrass health. Amphipods frequently comprise a large component of the diets of predatory fish and birds and thus play an important role in
the transfer of energy from primary producers to higher
trophic levels.
Due to their short generation times, direct development,
ease of culture, and intimate associations with sediments,
amphipods are routinely used in ecotoxicology as test
organisms for evaluating sediment and water quality and
as biomonitors for environmental contamination.
Bibliography
Burton, G. A., Jr., Denton, D. L., Ho, K., and Ireland, D. S., 2003.
Sediment toxicology testing: issues and methods. In Hoffman,
D. J., Rattner, B. A., Burton, G. A., Jr., and Cairns, J., Jr.
(eds.), Handbook of Ecotoxicology. Boca Raton: CRC Press,
pp. 111–150.
Edgar, G. J., and Shaw, C., 1995. The production and trophic ecology of shallow-water fish assemblages in southern Australia II.
Diets of fishes and trophic relationships between fishes and benthos at Western Port, Victoria. Journal of Experimental Marine
Biology and Ecology, 194, 83–106.
Raffaelli, D. G., 2006. Biodiversity and ecosystem functioning:
issues of scale and trophic complexity. Marine Ecology Progress
Series, 311, 285–294.
Whalen, M. A., Duffy, J. E., and Grace, J. B., 2013. Temporal shifts
in top-down vs. bottom-up control of epiphytic algae in
a seagrass ecosystem. Ecology, 94, 510–520.
Horton, T., Lowry, J., and De Broyer, C., (2013 onwards) World
Amphipoda Database. Accessed at http://www.marinespecies.
org/amphipoda.
ANADROMOUS
Charles A. Simenstad
School of Aquatic and Fishery Sciences, University of
Washington, Seattle, WA, USA
Definition
Organisms such as fishes which hatch in fresh water and
migrate to higher salinities such as the sea to mature and
then migrate back into fresh water to spawn.
Background
Originating in the nineteenth-century Russian literature
and refined from the original term (“contranatant”; Meek,
1916; Subnikov, 1976) by Meyers (1949), anadromous is
one of the three types of migration between the sea and
fresh water (McDowall, 1987). The directed movement
by anadromous fish between these markedly different
habitats is specifically associated with reproductive phases
of their life cycle. Of the approximately 20,000 species of
fish around the world (Cohen, 1970), McDowall estimated
that 54 % are anadromous. They are most common in
northern subpolar and cooler temperate waters.
Amphipods, Figure 1 Grazing amphipods from the family Ampithoidae are abundant in estuarine seagrass beds.
18
ANADROMOUS