Marine Mammal Biology Conservation 2024 BB PDF

Marine biology field course (Simon’s town, SA) 20 credits 2-week residential course COSTS: estimated £2500 (includes airfare, accommodation, meals, diving equipment) WHERE: False Bay, Simonstown, South Africa WHAT: SCUBA Diving expedition to study marine biodiversity off the...

Marine biology field course (Simon’s town, SA) 20 credits 2-week residential course COSTS: estimated £2500 (includes airfare, accommodation, meals, diving equipment) WHERE: False Bay, Simonstown, South Africa WHAT: SCUBA Diving expedition to study marine biodiversity off the southernmost most of Africa. - Gain and perfect skills in scientific diving - Study rocky reef and kelp forest ecology - Swim and dive with penguins, 7-gilled sharks and Cape fur seals - Photograph eagle rays, carpet sharks and gas-flare nudibranchs - Contribute to conservation of the marine environment Information Session: Tuesday 29 th October 14:00 – 15:00 Edith Morley 125  Biology and conservation of marine mammals Dr. Manuela Gonzalez Suarez  Marine mammal biology 1. Value the diversity of marine mammal species Today’s 2. Recognize different species as marine mammals and their adaptations Intended 3. Describe the ecological roles of marine mammals Learning Outcomes What are the threats to marine mammals? 4. Revise current issues in marine mammal conservation Marine mammal diversity  Now Artiodactyla Whales, porpoises, dolphins Seals, sea lions, polar bear, sea otter Manatees, dugongs Foote et al (2015) Nature Genetics 47, 272–275  Cetacea - Artiodactyla Oldest known cetaceans appeared ~55 million years ago Related to even-toed ungulates (deer, sheep) Closest living relatives are hippos Bottlenose dolphins Price (2005) Zimmer (2001) Biol. Rev 80: 445-473 The Tangled Bank Cetacean adaptations Fusiform, streamlined body shape Paddle-shaped front limbs, vestigial hind limbs No external digits or claws Tail flattened laterally with horizontal flukes at the tip Vestigial ear pinnae Internal genitalia Hairless (some young have hair on their snouts) Thick subcutaneous blubber layer filled with fat and oil External blowhole (“nose”) on the top of the head Humpback whale  IUCN recognizes 93 species (25 found in and around UK waters) Extant Two sub-orders cetaceans Mysticeti (baleen whales) 15 species Odontoceti (toothed whales) 78 species  Rice’s whale (Balaenoptera ricei) For comparison blue whales are about 160 tonnes  Mysticeti Baleens (keratin) for filter feeding – fish, krill, and plankton No teeth and expanded jaws Large size (6 m pygmy right whale to 31 m blue whale) Most are migratory (polar waters for summer feeding – tropical waters for birthing/calving) Humpback whale Mysticeti (baleen whales) 15 species Family Balaenidae (right whales, 4 species) Family Neobalaenidae (Pygmy right whale) Family Eschrichtiidae (Gray whale) Family Balaenopteridae (rorquals, 9 species) Common minke Antarctic minke Sei Bryde’s Blue Omura’s Humpback Fin Rice’s (2021)  Odontoceti Have teeth – eat fish, crustaceans, cephalopods, and other marine mammals Medium to large size (1.4 m vaquita to 20 m sperm whale) Echolocation to find prey and navigate – from melon (forehead) Diverse habitats including Amazon river Odontoceti (78 species) Family Physeteridae (Sperm whale) Family Kogiidae (Pygmy sperm whale, Dwarf sperm whale) Family Ziphiidae (beaked whales, 24 species) Family Platanistidae (Ganges river dolphin, Indus river dolphin. 2021) Family Iniidae (Amazon river dolphin) Family Lipotidae (Yangtze river dolphin or Baiji – possibly extinct) Family Pontoporiidae (Franciscana or La Plata dolphin). Family Monodontidae (Beluga, Narwhal) Family Delphinidae (37 species) Family Phocoenidae (porpoises, 7 species)  Figure 1 Whale fall (carcasses) Figure 1 All are in family Ziphiidae except Sperm whale (Physeteridae) Dive adaptations Store oxygen in their blood and muscles High levels of haemoglobin and myoglobin Reduce heart rate during diving and temporarily shut down some organs (eg liver and kidneys)  Carnivora Not all Carnivora are marine mammals Van Valkenburgh & Wayne (2010) Current Biology 20: 915-919 Pinnipedia (suborder) Oldest pinniped fossils 30.6–23 million years ago in the North Pacific Most closely related to bears (Ursidae) and weasels and raccoons (Musteloidea) Berta et al (2018) Annu Rev Earth Planet Science 46: 203-228 Pinnipedia (suborder) Family Odobenidae (1 species, walrus) Family Otariidae (fur seals and sea lions, 15 species +1 EX) Family Phocidae (true seals, 19 species) California sea lion Harbour seal  Pinnipedia Generally fusiforme body Four distinct limbs Otariidae and walrus front flippers are larger and support walking Phocidae front flippers are smaller and not used for walking Small tails  Pinnipedia Otariidae and walrus have external pinnae (ears), phocidae do not Thick blubber layer Visual predators, with sensitive whiskers used to find prey (krill, fish, cephalopods, penguins and other pinnipeds –leopard seal) Many are gregarious Pinnipeds ecological roles Top predators in many ecosystems, regulating prey populations Movement of nutrients between marine and terrestrial environments Bottom feeders like walrus can disturb (and make available) nutrients in the sediment Other Carnivora Family Mustelidae Sea otter and marine otter Family Ursidae Polar bear  Order Sirenia Fusiform bodies Marine and river systems More rounded tail flukes Largely herbivores (seagrass, algae, mangrove leaves, and palm fruit that falls into the water)  Order Sirenia Family Trichechidae (3 species) West Indian manatee African manatee Amazonian manatee Family Dugongidae (1 sp) Dugong (bi-lobed tail) Sea cow discovered by Europeans in Extinct 1741, hunted for its bubbler, extinct by 1768 27 years to extinction Sirenians ecological roles Top grazers keeping sea grass “prairies” Nutrient cycling (lots of sea grass in, lots of … out) Why are all these species called marine mammals? Spends part or all of their life at sea Always Foraging ? Why are all these species called marine mammals? Spends part or all of their life at sea Always Foraging Sea ice Why are all these species called marine mammals? Spends part or all of their life at sea Some live in rivers!! Sirenians in coastal areas or rivers Four river dolphin species (+1 extinct recently) Marine mammal conservation What do you think are the biggest threats to marine mammals?  Threats ila et al (2018) Biol Cons 221: 44-58 Another problem: lack of informati on 10/93 cetaceans are Data Deficient Where are the threats? ila et al (2018) Biol Cons 221: 44-58  Threats continue and can intensify International Whaling Commission founded in 1946 In 1982 pause on commercial whaling of all species Norway and Iceland continued commercial whaling Aboriginal subsistence and scientific whaling are allowed  But some good news too: conservation success he USA, the Endangered Species Act has helped the recovery of several species marine mammal populations studied, only 2 pops are still declining Valdivia et al (2019) PLoS ONE 14: e0210164 More and more Marine Protected Areas https://www.protectedplanet.net/ marine  202 3 https://www.protectedplanet.net/ marine But good management and monitoring needed, paper protected areas are not helpful To summarise 1. Marine mammals are a diverse, non-monophyletic group (polyphyletic) Most live or forage at sea, but some live in rivers or estuaries Include species from three different mammalian orders Play key roles in nutrient cycles and top-down regulation of ecosystems (as predators and herbivores) 2. Main threat to marine mammals is bycatch Also important pollution (chemical and noise), whaling, collision with boats, and diseases Different impacts in different areas New threats but also reasons for hope Evidence of recoveries More and more MPAs  Additional reading on Blackboard [email protected]