A comparison of baleen whale density estimates derived from overlapping satellite imagery and a shipborne survey

first_imgAs whales recover from commercial exploitation, they are increasing in abundance in habitats that they have been absent from for decades. However, studying the recovery and habitat use patterns of whales, particularly in remote and inaccessible regions, frequently poses logistical and economic challenges. Here we trial a new approach for measuring whale density in a remote area, using Very-High-Resolution WorldView-3 satellite imagery. This approach has capacity to provide sightings data to complement and assist traditional sightings surveys. We compare at-sea whale density estimates to estimates derived from satellite imagery collected at a similar time, and use suction-cup archival logger data to make an adjustment for surface availability. We demonstrate that satellite imagery can provide useful data on whale occurrence and density. Densities, when unadjusted for surface availability are shown to be considerably lower than those estimated by the ship survey. However, adjusted for surface availability and weather conditions (0.13 whales per km2, CV = 0.38), they fall within an order of magnitude of those derived by traditional line-transect estimates (0.33 whales per km2, CV = 0.09). Satellite surveys represent an exciting development for high-resolution image-based cetacean observation at sea, particularly in inaccessible regions, presenting opportunities for ongoing and future research.last_img read more

Watch: Ryan Giggs explains how Manchester United set up to get the best out…

first_imgImage Courtesy: The Coaches’ Voice/GettyAdvertisement 6afziNBA Finals | Brooklyn Vsua2Wingsuit rodeo📽Sindre E04e( IG: @_aubreyfisher @imraino ) 7izliWould you ever consider trying this?😱6sctCan your students do this? 🌚btrRoller skating! Powered by Firework Today is the day when Cristiano Ronaldo scored his first goal for Manchester United in 2003. Under the guidance of Sir Alex, the FC Porto youngster’s journey at Old Trafford created one of the best players the game has ever saw, and on the same date, Club legend Ryan Giggs has come up with a clip explaining how the Red Devils operated to get the ball to Ronaldo.Advertisement Image Courtesy: The Coaches’ Voice/GettyThe current Welsh national team gaffer’s documented video, uploaded on Twitter by The Coaches’ Voice is part of their ‘Masterclass’ series of tactics explanation clips. Check it out below-Advertisement In the clip, the Devils veteran explains how under his captaincy, the team, when in possession would always aim to get the ball to Ronaldo, who was developing as a winger back in the day. With his blistering pace and agility, the young Portuguese sensation became an ordeal for opposition defenders.“I always knew that that ball over the left center half’s head was on for Cristiano”The 45 year old congregated his time with the team and how every outfield players aimed the ball towards the young Portuguese.“I would get the ball to Rooney, he would turn out and get it to Cristiano.”“get the ball to Michael, open up, get it to Cristiano.”Ronaldo, currently at Juventus, arrived at the Theater of Dreams in 2003 from Porto, and after six years under Fergie, flew over to the Spanish Capital to join Los Blancos, before joining the Old Lady in 2018. Advertisementlast_img read more