One shark, two shark, three shark, four

Posted by on Dec 2, 2013 in Sighting Updates | No Comments

On September 11, 2009 and 2011, researchers from the Grand Manan Whale & Seabird Research Station conducted aerial surveys for basking sharks in the Bay of Fundy to estimate the abundance of basking sharks in this area. Three researchers conducted the surveys, from a small plane (Cesna 337) flying at 1000 feet at 110 knots. Each survey lasted about 5 hours.

Researchers from the Grand Manan Whale & Seabird Research station preparing for basking shark surveys in 2009

Researchers from the Grand Manan Whale & Seabird Research station preparing for basking shark surveys in 2009. Photo by H. Koopman.

 

The aerial survey followed the same track in 2009 and 2011 and covered 991 km.

Aerial survey track for basking shark s in the Bay of Fundy, conducted September 11, 2009 and 2011.

Aerial survey track for basking sharks in the Bay of Fundy, conducted September 11, 2009 and 2011 by researchers at the Grand Manan Whale & Seabird Research Station

 

We sighted a total of 26 basking sharks during the 2 aerial surveys. Our analysis, which takes into account the proportion of time sharks spend at the surface (and can thus be spotted from a plane) and other factors, gave a population estimate of about 542 sharks in 2009 and 632 sharks in 2011.

Photo by Wayne Davis showing what basking sharks look like from the air. During the 2009 and 2011 surveys by researchers at the Grand Manan Whale & Seabird Research station, basking sharks were only ever sighted alone (not in groups as shown in this photo).

Photo by Wayne Davis showing what basking sharks look like from the air. During the 2009 and 2011 surveys by researchers at the Grand Manan Whale & Seabird Research station, basking sharks were only ever sighted alone (not in groups as shown in this photo).

 

Recently, our paper  on the results of our aerial surveys, entitled “Population density and abundance of basking sharks Cetorhinus maximus in the lower Bay of Fundy, Canada” was accepted in the journal Endangered Species Research. 

It has not yet been published, but you can see our pre-press abstract here: http://www.int-res.com/prepress/n00567.html

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