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Reduced prey availability and nutritional ber of cetacean species as food reservoir, thus
stress may be an issue in the reduced dolphin making them more exposed to their toxic effects
abundance or mass mortality events observed in at a time when they are already debilitated by
several Mediterranean areas. For instance, an un- food scarcity.
usually high effort devoted to food search has
been recorded for Mediterranean common bottle-
nose dolphin population units that have been List of references
consistently studied during the last decade (Politi
1998, Bearzi et al. 1999). Approximately 40% of Agardy T., Engdahl S. In press. Marine protected area net-
works and corridor approaches: Optimal ways to con-
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eastern Ionian Sea, where demersal fish resources Practice.
have been over-fished (Papaconstantinou et al. Aguilar A. 2000. Population biology, conservation threats
1985a,b) were reportedly emaciated (Politi et al. and status of Mediterranean striped dolphins (Stenella
coeruleoalba). Journal of Cetacean Research and Man-
2000). In the same area, a decline in short- agement 2:17-26.
beaked common dolphin numbers was consistent Aguilar A., Raga J.A. 1993. The striped dolphin epizootic in
with the hypothesis of reduced prey availability the Mediterranean Sea. Ambio 22(8):524-528.
or increased prey patchiness (Politi and Bearzi, In Alverson D.L., Freeberg M.H., Murawski S.A., Pope J.G.
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cards. FAO Fisheries Technical Paper 339. Food and
quate nutrition has been cited possibly having Agriculture Organization of the United Nations, Rome.
played a role in an epizootic outbreak (Aguilar 233 pp.
and Raga 1993) and to be responsible for their Alverson D.L., Hughes S.E. 1996. Bycatch: From emotional
extremely elevated age at sexual maturation ob- to effective natural resource management. Reviews in
Fish Biology and Fisheries 6:443-462.
served in this region as compared to other con- Andreoli M.G., Campanella N., Cannizzaro L., Garofalo G.,
specific populations inhabiting waters were food Giusto G.B., Jereb P., Levi D., Norrito G., Ragonese S.,
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overfishing may contribute to a reduced prey ansie. La Pesca Europea 2:4-5.
availability, or induce changes that can affect the Apanius V. 1998. Stress and immune response. Pp. 133-153
marine food webs. For instance, global environ- in A.P. Møller, M. Milinski and P.J.B. Slater (Eds.)
mental changes (MacGarvin and Simmonds Stress and behavior. Vol. 27 in Advances in the study of
behavior. Academic Press, London.
1996) may combine with overfishing and habitat Arcand–Hoy L.D., Benson W.H. 1998. Fish reproduction:
contamination to jeopardise ecosystem dynamics. An ecologically relevant indicator of endocrine disrup-
Moreover, the build-up of man-made toxic con- tion. Environ. Toxicol. Chem. 17(1):49-57.
taminants may reduce the reproductive success or Archer F., Gerrodette T., Dizon A., Abella K., Southern S.
2001. Unobserved kill of nursing dolphin calves in a
depress the immune-responses of top predators, tuna purse-seine fishery. Marine Mammal Science
including both fish and marine mammals (e.g., 17(3):540-554.
Fossi et al., In press). Ardizzone G.D., Belluscio A., Schintu P. 1994. Considera-
The impact of man-made toxic compounds on zioni sullo strato di sfruttamento delle risorse demersali
(Isola di Giannutri –
Foce del Garigliano). Biol. Mar.
biologic communities is a major source of con- Medit. 1(2):43-46.
cern. Many organochlorine compounds, for in- Azzali M., Luna M. 1988. Una nota preliminare sulle risorse
stance, are responsible for endocrine dysfunc- pelagiche nei mari italiani, stimate con tecniche acus-
tions in a number of organisms, including ceta- tiche. Atti del Seminario delle unità operative responsa-
cean preys. By affecting the reproductive suc- bili dei progetti di ricerca promossi nell'ambito dello
schema preliminare di piano per la pesca e l'acquacul-
cess and the sex ratio of a species, contamination tura. Vol. 1. Pp. 101-171.
may negatively affect fish stocks (Focardi et al. Baker R.R. 1978. The evolutionary ecology of animal mi-
1998, Johnson et al. 1988, IEH 1995, Janssen et gration. Holmes and Meier Publishers, New York. 1012
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cascade effects on both cetaceans and fisheries. comune (Delphinus delphis) osservate in Liguria e pro-
Finally, it must be observed that contamina- dotte dal generalizzarsi della pesca intensiva. Neptunia
tion and food scarcity may act synergistically, as 10:156-164.
malnutrition may prompt mobilisation of lipo- Bearzi G., Politi E., Notarbartolo di Sciara G. 1999. Diurnal
philic contaminants that are “stored” in the blub- behavior of free-ranging bottlenose dolphins in the

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