the article below has just been published online.
Bearzi G., Politi E., Agazzi S., Azzellino A. 2006.
Prey depletion caused by overfishing and the decline of marine megafauna in eastern Ionian Sea coastal waters (central Mediterranean).
Biological Conservation 127(4):373-382.
ABSTRACT - Surveys primarily aimed at determining dolphin encounter rates were conducted from small inflatable craft in eastern Ionian Sea coastal waters between 1997-2004. During 633 surveys totalling 21276 km of effort, observations of cetaceans and other marine species spotted in a study area of 480 km2 were systematically recorded. Common dolphin encounter rates declined 25-fold across the study period, steadily decreasing from 2.18 encounters/100km in 1997 to 0.09 encounters/100km in 2004. Encounter rates of tuna also declined significantly. Swordfish encounter rates dropped from 1.03 encounters/100km in 1997 to 0-0.12 in 1998-2004. Encounter rates of bottlenose dolphins did not show significant trends. The decline of high-order marine predators feeding on epipelagic prey was consistent with the hypothesis of prey depletion, likely resulting from intensive exploitation of local fish stocks, particularly anchovies and sardines. The catholic feeding habits and opportunistic behaviour of bottlenose dolphins may allow them to withstand the effects of overfishing at their present low density.
Those who are interested can find this article and a few related ones at:
http://www.tethys.org/giovanni_bearzi.htm >> click on Publications
Best regards,
Giovanni Bearzi
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Giovanni Bearzi, Ph.D.
[EMAIL PROTECTED]
President, Tethys Research Institute
Viale G.B Gadio 2, 20121 Milano, Italy
http://www.tethys.org/
http://www.tethys.org/giovanni_bearzi.htm
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