jueves, abril 25, 2024

Season of the Humpback Whales


by Katia Silva, Marine Biologist and guide at Cabo Trek www.cabotrek.com For marine mammals like humpback whales, baseline data needs to be collected over large areas and multiple areas to be useful. Until recently, this was prohibitively costly and time consuming; however, scientists are finding increasingly efficient, low-cost methods to collect large amounts of data. Cetaceans such as whales and dolphins were considered a motivator for many people to engage with citizen science projects and a way to connect humans to nature and potentially bridge the gap between science and the public. Every whale is unique. Observe the natural marks such as the pigmentation, coloration and the shape of the fluke and the dorsal fin. Notice also the presence of deformities or scars. Photo-identification has been used since the 1930’s on a number of species including elephants, gorillas, seals, giraffes and leopards. It is used today by researchers around the world. It facilitates the monitoring of movements, social organization, and behavior of whales, as well as estimating their abundance. Every hour spent at sea with whales translates into several of hours of work analyzing data. Photos are carefully analyzed, compared to those of several individuals and finally matched according to a series of rigorous criteria. With time, the technique has evolved; rolls of black-and-white film have been abandoned in favor of the digital photos used today. Such photos, reworked or processed by computer, are far quicker in revealing the identities of these giants! In just this season Cabo Trek identified 482 whales and their catalogue now has 639 individual whales. All this information was collected by doing 3 tours per day every week since the start of the season (December 15th). The pictures of the flukes were shared with a large online database called Happywhale, an important tool for citizen scientists to help in whale conservation, and throughout this season made it possible to know some curiosities about the whales that come to Cabo San Lucas: CTHW#189: This whale was sighted in California on December 6th, 2016 and the same whale was sighted in Cabo San Lucas on December 19th, 2017. It is the fastest migration know so far. CTHW#315: This whale has been sighted since 1990. It is the oldest whale sighted from the catalogue. CTHW#536: This whale tried to intervene when a pod of a killer whales attacked a baby gray whale. CTHW#519: The most sighted (21 times) whale since 2009. CTHW#458 CTHW#496 CTHW#579: These whales were sighted in Alaska. ]]>

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