Biology Reference
In-Depth Information
TABLE 10.2
Contamination-Induced Behavioral Changes and Ecological Consequences for Estuarine Fish and
Crustaceans
Killifish
(
Fundulus
heteroclitus
)
Bluefish
(
Pomatomus
saltatrix
)
Grass Shrimp
(
Palaemonetes
pugio
)
Blue Crab
(
Callinectes
sapidus
)
Fiddler Crab
(
Uca pugnax
)
Studied Effect
Feeding behavior
⇘
⇘
⇘
⇘
⇘
Diet
Detritus
Empty guts
NS
NS
Detritus
Predator avoidance
⇘
NS
=
⇗
⇗
General activity
⇘
⇘
⇘
⇘
NS
Size
⇘
⇘
⇗
⇗
⇗
Population density
⇘
NS
⇗
⇘
NS
Reproduction
⇗
NS
⇗
⇗
NS
Thyroid √ √
Neurotransmitters √ √
Source:
Weis, J.S. et al.,
Biosciences
, 61, 375-385, 2011. With permission.
Note:
=, no effect observed; ⇗ and ⇘, positive and negative effects; √ (checkmarks), effects were observed; NS,
not studied.
Callinectes sapidus
, this has been attributed to a top-down effect, involving respectively
the decreased predation by a depleted population of killifish in polluted sites, or a fish-
ing ban on the crab, an edible species with chemical residues in their tissues reaching
or exceeding regulation limits for health safety. In the case of the fiddler crab
U. pug-
nax
, the larger size at the contaminated site may be explained by less competition in a
population with a lower density (as a result of impairment of larvae by contaminants
and decreased recruitment) and decreased predation by the blue crab. The disturbance of
feeding behavior and the consequences on predator-prey interactions in all five species
are well established, but Weis et al. (2011) also highlighted a number of key questions that
are important for the ecological effects of chemicals on communities: the biomagnifica-
tion of some contaminants leading to higher exposure in predators than in prey; certain
biological traits favoring tolerance (e.g., elimination of metal by molting in crustaceans)
and more generally, the differential sensitivity and ability of different taxa to deal with
and adapt to different types of contaminants.
Several studies have shown a link between exposure of fish to sublethal doses of various
contaminants and reproductive behavior, but few authors have seriously examined poten-
tial consequences for reproduction success and population effects. In their review on fish,
Jones and Reynolds (1997) mentioned two studies that directly measured a negative effect
on reproductive success, whereas a possible decrease in the reproductive success of
Tilapia
rendalli
was inferred in areas treated with pesticides in the Okavango Delta (Botswana).
The behavior of fish larvae can also have a crucial role in reproductive success. DDT and
PCBs transferred to the progeny through egg yolk are able to alter responses of larvae to
warning signals. Even if these symptoms become less pronounced during development
(exogenous food replacing the yolk as the energy source, biological dilution of contami-
nants in growing tissues), they are a clear handicap at a key phase of recruitment success.
This point seems particularly critical since organochlorine concentrations in gonads and
eggs of experimental fish were of the same order of magnitude as concentrations deter-
mined in fish contaminated in the wild (Faulk et al. 1999; McCarthy et al. 2003).
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