[MARMAM] new article on strandings as population indicators

Hélène Peltier hpeltier at univ-lr.fr
Tue Apr 23 00:32:39 PDT 2013

Dear colleagues,

I am glad to inform you that a new article is now available online:


*The Stranding Anomaly as Population Indicator: The Case of Harbour 
Porpoise /Phocoena phocoena/ in North-Western Europe.*

Helene Peltier, Hans J. Baagøe,Kees C. J. Camphuysen,Richard Czeck,Willy 
Dabin,Pierre Daniel,Rob Deaville,Jan Haelters,Thierry Jauniaux,Lasse F. 
Jensen,Paul D. Jepson,Guido O. Keijl,Ursula Siebert,Olivier Van 
Canneyt,Vincent Ridoux
Ecological indicators for monitoring strategies are expected to combine 
three major characteristics: ecological significance, statistical 
credibility, and cost-effectiveness. Strategies based on stranding 
networks rank highly in cost-effectiveness, but their ecological 
significance and statistical credibility are disputed. Our present goal 
is to improve the value of stranding data as population indicator as 
part of monitoring strategies by constructing the spatial and temporal 
null hypothesis for strandings. The null hypothesis is defined as: small 
cetacean distribution and mortality are uniform in space and constant in 
time. We used a drift model to map stranding probabilities and predict 
stranding patterns of cetacean carcasses under H_0 across the North Sea, 
the Channel and the Bay of Biscay, for the period 1990--2009. As the 
most common cetacean occurring in this area, we chose the harbour 
porpoise /Phocoena phocoena/ for our modelling. The difference between 
these strandings expected under H_0 and observed strandings is defined 
as the stranding anomaly. It constituted the stranding data series 
corrected for drift conditions. Seasonal decomposition of stranding 
anomaly suggested that drift conditions did not explain observed 
seasonal variations of porpoise strandings. Long-term stranding 
anomalies increased first in the southern North Sea, the Channel and Bay 
of Biscay coasts, and finally the eastern North Sea. The hypothesis of 
changes in porpoise distribution was consistent with local visual 
surveys, mostly SCANS surveys (1994 and 2005). This new indicator could 
be applied to cetacean populations across the world and more widely to 
marine megafauna.

All the best
Helene Peltier



Observatoire PELAGIS UMS 3462
Université de La Rochelle-CNRS
5, allées de l'océan
17000 La Rochelle, France

hpeltier at univ-lr.fr

+33 (0) 16 49 67 82 /+33 (0) 6 82 74 08 41

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