GEOG 303 Conservation and Ecology of Whales - Topics 1 to 3 PDF

GEOG 303 Conservation and Ecology of Whales Topic One: What is a Whale? Part One: What makes a whale a whale? 62/47 Join at: vevox.app ID: 127-680-357 Question slide What makes a whale a whale? 62 Join at: vevox.app ID: 127-680-357 Showing Results What makes a whale...

GEOG 303 Conservation and Ecology of Whales Topic One: What is a Whale? Part One: What makes a whale a whale? 62/47 Join at: vevox.app ID: 127-680-357 Question slide What makes a whale a whale? 62 Join at: vevox.app ID: 127-680-357 Showing Results What makes a whale a whale? RESULTS SLIDE What makes a whale a whale? The very basics. Collectively termed cetaceans (or the Cetacea) Lives in marine environments but some live in rivers! Mammal warm blooded breathes air births live young at advanced state of development Grouped with other marine mammals that evolved from land to water  All marine mammals (e.g. whales, seals, sea lions, sirenians), even if not evolutionarily linked, have evolved to adapt to the marine environment like fishes Convergent evolution Taxonomy of whales, dolphins and porpoises Kingdom - Animalia Phylum - Chordata Class - Mammalia Sub-order - Mysteceti Order - Cetacea Sub-order - Odontoceti Family- Delphindae Genus - Orcinus Species - orca  Cetacea Mysticeti (baleen whales) Rorquals Gray whale Bowhead Pygmy and right right whales whale skull rostrum Mysticete food  Cetacea Mysticeti Odontoceti (baleen whales) (toothed whales) Rorquals Gray Narwhals Dolphins whale Bowhead and Beaked Pygmy and right belugas whales right whales Sperm Porpoises whale whales skull rostrum Odontocete food Odontocete versus Mysticete blowholes  GEOG 303 Conservation and Ecology of Whales Topic One: What is a Whale? Part Two: Evolution of Whales Zimmer, 2014 Pakicetus Phylum: Chordata Era: Early Eocene (52-48 Ma) Class: Mammalia Discovered in modern day Pakistan (thus paki – Order: Cetacea cetus) in 1981. Suborder: Archeoceti Family: Pakicetidae Lived a semi-aquatic life, near warm coastal and Genus: Pakicetus riverine systems, likely similar to hippo Species: attocki, innachus behaviour Pakicetus Limbs adapted for walking as a quadruped But likely partially amphibious Similar to a large dog with slim limbs like a deer Pakicetus Skull resembling early mammals Ear encased in bony structure termed auditory bula characteristic of all cetaceans specialized for underwater hearing Teeth consistent with a carnivore diet likely ate small mammals, reptiles, amphibians, birds, and fish Pakicetus Long, thin skull shape of cetaceans Nostrils at the anterior end of what would become the rostrum in whales Pakicetus Significant species as a critical transitional species between terrestrial and aquatic cetaceans Possessed both terrestrial and aquatic features but not fully adapted to aquatic life Zimmer, 2014 Ambulocetus Phylum: Chordata Era: Early Eocene (50-48 Ma) Class: Mammalia Discovered in modern day Pakistan in 1994. Order: Cetacea Ambulare (to walk) + cetus (whale) Suborder: Archeoceti Lived an amphibious life, near warm coastal and Family: Ambulocetidae riverine systems, likely similar to otter behaviour Genus: Ambulocetus Likely hunted in aquatic environments and came Species: natans ashore to mate and breed Ambulocetus Limbs adapted for walking as a quadruped More amphibious than Pakicetus Webbed toes, rear legs slung back May have moved on land like an otter or sea lion Ambulocetus Similar long narrow skull as Pakicetus Carnivore teeth Partially evolved blowhole, more posterior to Pakicetus Likely spent more time in the water than Pakicetus Ambulocetus Maybe most significant evolutionary link between amphibious and fully aquatic cetaceans But what adaptive pressures drove this evolution? ##/## Join at: vevox.app Join: vevox.app ID: 130-930-461 Enter Text What adaptive pressures might have caused this and Press Send rare evolution of cetaceans from land to ocean? ##/## Join at: vevox.app ID: XXX-XXX-XXX Results slide What adaptive pressures might have caused this rare evolution of cetaceans from land to ocean? RESULTS SLIDE & Basilosaurus Zimmer, 2014 Basilosaurus 18 m Phylum: Chordata Era: Late Eocene (41-35 Ma) Class: Mammalia Order: Cetacea Discovered in modern day Alabama in 1843. Suborder: Archeoceti Initially thought to be a marine reptile, thus the Family: Basilosauridae name “King Lizard” Subfamily: Basilosaurinae Not recognized as an ancient cetacean until Genus: Basilosaurus many years later Species: cetoides, isis Fully aquatic 2010 fossil evidence from Wadi al Hitan, Egypt, revealed that Basilosaurus isis fed on Durodon atrox; it likely also fed on fish and sharks Basilosaurus Greatly elongated spine (A) Very small hind limbs (B) not attached to skeleton could not have supported weight may have had a mating purpose Vertebrae proportions at the tip of the tail may have been robust enough to support small tail flukes Basilosaurus Shorter rostrum Retains large, bone-crushing teeth Proto-blowhole farther back than Ambulocetus & Basilosaurus Zimmer, 2014  GEOG 303 Conservation and Ecology of Whales Topic One: What is a Whale? Part Three: Taxonomy, Physiology, Anatomy  2 genera 7 to 9 species (unclear) streamlined small dorsal fin long ventral pleats from snout to navel moderate length baleen plates relatively flat upper jaw  1 species short baleen 3 short ventral pleats “knuckles” along tailstock  1 species somewhat curved upper jaw dorsal fin 2 short ventral pleats  2 Genera, 2 species robust Pronounced curvature to upper jaw long baleen ##/## Join at: vevox.app Join: vevox.app ID: 119-131-971 Why do you think there are so many more Odontocete than Mysticete species? ##/## Join at: vevox.app ID: XXX-XXX-XXX Results slide Why do you think there are so many more Odontocete than Mysticete species? RESULTS SLIDE Spine evolves to be more S shaped because of loss of legs Locomotion in vertebrates The Nested Region Hypothesis Precaudal segment is the same as humans, but whales have the additional Caudal region that creates the S-shape of the spine (Nested Region Hypothesis) All whales have the same modules, but the Regions vary between whales The Nested Region Hypothesis Number of Vertebrae changes between species (and varies between shallow and open ocean depths) More musculature=more speed=more vertebrae Odontocete anatomy Floating pelvis, remnants of legs, all whales have these Mysticete anatomy Rorqual mouth structure Upper Jaw fits within lower jaw Mysticete digestion Mysticete stomachs have several chambers, similar to ruminants 1. Forestomach (rumen): peristalsis breaks down food 2. Fundic chamber (cardiac stomach): acid and enzymes digest food 3. Pyloric chamber (pylorus): mucus produced to facilitate intestinal transit Combined actions of these chambers allow digestion of chitinous exoskeletons of prey  Cetacean respiratory anatomy Cetaceans have huge, extremely high-capacity lungs and exchange up to 90% of their lung volume with each breath The laryngeal sac performs 4 functions: 1. as a resonating chamber that amplifies sound 2. contributes to the diversity of vocalizations 3. regulates airflow 4. manages pressure in deep- diving whales  Whales have huge amounts of myoglobin compared to land creatures = Brachychardia  GEOG 303 Conservation and Ecology of Whales Topic Two: Behaviour and Communication Part One: Ranges and Migration Introduction Migration is central to the life-history of many species of cetaceans Some whales, particularly Mysticetes, exhibit some of the longest migrations in the world The general pattern for migration is feeding in cold, nutrient-rich waters and breeding and calving in warm waters Some Odontocetes do not move very much, others are nomadic, and some exhibit short migrations In winter: moves to warmer waters (breeding/calving) In summer: moves to colder waters (feeding) Mostly stay near the shallower waters/coastal shelves because those locations are more productive In the southern hemisphere the summer months are the winter (moves to warmer waters) and Key characteristics of humpback whale range & migration Live in all oceans of the world 14 sub-populations Every population except one (Arabian Sea) performs long-distance seasonal migration (up to 8,000km) Summers: cold, productive, high latitude waters → feeding Winters: warm, low-latitude waters → breeding, calving We don't know a lot about Blue Whales because they spend a lot of time in the deep ocean Possible year-round feeding, breeding and calving in these regions *We don't really know Key characteristics of blue whale range & migration Live in all oceans of the world except the Arctic Ocean 5 recognized sub-species, including Pygmy Blue Whale Usually found in off-shore waters Migration routes and feeding grounds are not well understood A few predictable locations such as the Gulf of St. Lawrence. Main part of population feeds off the bottom Key characteristics of gray whale range & migration Live in North Pacific Ocean coastal waters, mostly along the west coasts of Canada, United States, and Mexico 2 sub-populations: Eastern and Western Pacific: WP is an extremely small population Winter: southern latitudes, breeding and calving in Mexican lagoons along Baja California Summer: main population migrates to Bering and Chukchi Seas, but are spread along coastal U.S. and Canada Longest migration of any mammal: round trip of 20,000km Key characteristics of bowhead whale range & migration Live in the Arctic Ocean, as well as extreme northern Pacific and Atlantic Oceans 4 recognized “stocks” Longest migration is 1,500km Movements are generally to higher latitudes in summer The only baleen whale that lives in the Arctic We don't know a lot about their range Key characteristics of sperm whale range Live in extremely deep waters; only near shore if there are deep canyons Circumglobal across tropical and sub-tropical latitudes No established sub-populations Males can be quite nomadic and are sometimes seasonally found in temperate waters in both hemispheres during summer months Coastal BC has Resident (salmon eating) and Transient (seal eating) Transient have become more common due to decline in salmon but increase of seals BC Killer Whale ranges https://royalsocietypublishing.org/doi/10.1098/rsos.231368 - different pectorals - different girth - different fin Revised taxonomy of eastern North Pacific killer whales (Orcinus orca): Bigg’s and resident ecotypes deserve species status, Volume: 11, Issue: 3, DOI: (10.1098/rsos.231368) Suggested ranges for two new killer whale species - Biggs Orcas have no black intrusions on the saddle patch I - bigger than Resident orcas - larger dorsal fins, larger over all - Biggs live in smaller groups - more silent than the Residents - 3 Main Points of Difference: phenotype (looks differences), genotype (taxonomy is farther apart), and skull morphology (bigger, heavier, more muscle = Biggs) Key characteristics of killer whale range(s) Found in all oceans of the world Divided into 10 distinct ecotypes, based on range, morphology and behaviour Best known groups are along west coast of U.S. and Canada Northern residents: main range is northern half of Vancouver Is. and up into Alaskan Panhandle Southern Residents: main range is southern half of Vancouver Is. and as far south as California Bigg’s (transients): range widely from Bering Sea to California Offshore: not much known about this population Key characteristics of narwhal whale range & migration Live in the Arctic Ocean Majority of the species lives in deeper waters of the Davis Strait, between Baffin Island, Canada, and Greenland Move very little between summer and winter Named for the Irawaddy River which it can sometimes be found Key characteristics of Delphinid ranges Extremely varied: from rivers to coasts to open ocean Some divided into multiple geographic sub-populations, some not understood well enough to do so Key characteristics of beaked whale range(s) There are species of beaked whales in all oceans of the world Least known group of whales when it comes to ranges and migrations Some seem to have smaller ranges and some circumglobal Always inhabit very deep waters  GEOG 303 Conservation and Ecology of Whales Topic Two: Behaviour and Communication Part Two: Social Behaviour & Communication Introduction to social structure and behaviour Whales can be highly socialized organisms Odontocetes tend to have more developed social structure than Mysticetes Most Odontocetes live in social or family groups Most Mysticetes are loners, but are found together during mating season, as mother & calf, or in feeding aggregations Odontocete social structures and behaviours Odontocetes are found in groups, called pods, which are often extended families Pods are often structured as a matriarchy, with an older female “leading” the pod Pod members often cooperate to hunt There is often a social structure in which calves are taught skills and protected While not a universally accepted term, odontocetes can often be observed “playing,” which is likely part of skill teaching and social bonding Rubbing, biting, pushing around kelp, wave-riding, bow-riding, fluke / tail slapping, breaching SeaDoc Society  Orca Spirit Adventures B.C killer whale social structures and behaviours Northern and Southern Resident killer whales Live in matrilineal pods Organized around a female, her offspring, and her offsprings’ daughters Males stay with the pod of their mother until she C. Malcolm dies, when they might leave the pod Most often found in sub-pods (e.g. J, K, & L pods of southern residents) of less than 20 individuals When multiple pods meet and combine, this is called a “super pod” Inter-pod mating likely occurs during these gatherings There is often a lot of socializing behaviours Calves can be born at any time of year, but mostly in the spring Females play a large role in feeding, protection, and skill teaching Bigg’s killer whales (transients) Live in much more fluid pods, where individuals sometimes exchange between groups Do not form the long-term familial bonds that residents do Pods are much smaller, often five or less R. Baird individuals Exhibit less dramatic social behaviours Meetings of pods do not involve the behavioural displays of resident super pods. Sperm whale social structures and behaviours Wild Wonders of Europe  Live in highly stable matrilineal social groups, centered around females and their offspring, of 5 to 20 individuals Males live alone or in “bachelor pods” of individuals about the same age Can be found in colder, temperate Flickr waters but return to sub-tropical and tropical waters to visit the female groups Males will compete for females Calves are born in shallower, warmer waters Like killer whales, the females are caregivers and teachers to the younger whales Those that are post-reproductive remain in this role Bottlenose dolphin social structure and behaviours  Live in highly fluid pods This behaviour is called fission-fusion, in which individuals may separate (fission) or join together (fusion), based on social, foraging, mating, or environmental requirements Numbers may range from 2 to 1000 F. Nicklin Inshore groups are smaller than offshore groups There is no hierarchy in the pods, although males may show hierarchy in mating Exhibit alloparenting, where individuals other than the mother may care for and protect a calf Strong bonds can form in which individuals mostly socially interact with the same individuals over long periods of time Exhibit strong cooperative behaviour, particularly during foraging  Are highly “playful” Jump, surf in waves, bowride, play with objects, rub together Serves to strengthen social bonds and indicates intelligence Are known to learn from each other through observation and imitation C. Malcolm Some researchers have gone so far as to call bottlenose dolphin social structure a culture Mysticete social structures and behaviours Mysticetes have much less developed social structures that Odontocetes Most live a solitary life except for mating, caring for a calf, or arriving in the same place to form a feeding aggregation Of all Mysticetes, humpback whales may exhibit the most developed behaviours NOAA Fisheries Humpback whale social structure and behaviours C. Malcolm  Known for spectacular behaviours, such as breaching, tail lobbing, and flipper slapping Can also be curious of boats Only cetacean known to “sing” as part of mating behaviour C. Malcolm All males in the same breeding area “sing” the same song, which gradually changes over the mating season → let’s listen! “Gangs” of males will pursue and compete to mate with a female On feeding grounds, humpback whales can sometimes form cooperative feeding groups These associations are not necessarily social in nature However, individuals may sometimes form resting associations of a few individuals for a short period of time  Calves are born in shallow, warm waters Calves are only taken care of by the mother; there is no cooperative care as exhibited by Odontocetes This is typical of Mysticetes Hakai Magazine Cetacean Vocalizations and Communication How most odontocetes make sound Air is pushed through the nasal passages, augmented and varied through the dorsal bursae The phonic lips allow odontocetes to adjust the frequency and intensity of the sounds Sounds are focused and emitted through the melon Sound is received through the lower jaw and auditory bullae Let’s listen to some Odontocete echolocation and vocalizations (Clicks) (Squeaks) How sperm whales make sound Whale forces air through the right nasal passage, which twists and turns and reverberates sound Air forced through the monkey lips, which create clicks, which is reflected through the junk out into the water Thought that the whale might be able to change the shape of the spermaceti organ to aim the clicks - Monkey lips are similar to phonic lips - Junk is similar to melon Types of sperm whale sounds Clicks: Main method of echolocation Short busts of high-frequency clicks Used to find prey in the deep ocean Echoes of clicks are bouncing off objects are received through the lower jaw Codas: Patterned sounds that serve social functions Group identification to help identify each other and where they are Communication during social interactions Let’s listen to some sperm whale vocalizations then learn from some sperm whale researchers how they go about trying to figure out sperm whale language! How Mysticetes make sound Not able to echolocate like odontocetes Baleen whales use their larynx to produce sounds The laryngeal air sac amplifies and modulated the sounds Air passes over the U-shaped vocal folds and is transmitted through the ventral throat pleats into the water Let’s listen to some Mysticete Sounds emitted are groans and vocalizations! moans Blue whales can make the loudest animal sound in the world  GEOG 303 Conservation and Ecology of Whales Topic Three: Feeding Ecology & Ecological Niche Part One: Diet, Foraging, & Feeding Cetacean nutritional requirements Cetaceans, both Mysticetes and Odontocetes, require a high energy diet body size epidermis thermoregulation due to water dermis temperature (often cold) blubber activity (often migrating) adipose cells ‫ ؞‬require high energy prey and a lot of it connective tissue oily prey like krill, herring, or salmon fascia muscle Blue whales might consume up to 4 tons S. Boureghada of krill per day Killer whales might consume up to 175 kg (385 lbs) of salmon per day A large percentage of consumed prey is converted into blubber, high in protein and fatty tissue → energy storage Diet composition and feeding behaviour - Mysticetes Zooplankton (e.g. krill, mysids), or small fish Marine Stewardship Council krill Mongabay Small fish (e.g. herring) Institute of Marine Research Illustrations by U. Gorter  Rorquals engulf their prey Fin whales International Nature & Cultural Adventures  Rorquals engulf their prey Fin whales Humpback whales bubble net feeding 1 Humpback whales bubble net feeding 2 Right and bowhead whales skim feed North Atlantic right whale skim feeding Diet composition and feeding behaviour - Mysticetes amphipod B. Logan Orca Network ghost shrimp T.D. Clark crab mysid larvae P.J. Bryant NOAA Illustration by U. Gorter  Gray whales feed off the bottom and skim feed Gray whale bottom feeding Gray whale skim feeding F. Nicklin R. Bonner  In Clayoquot Sound, gray whales will switch rapidly from one prey source to another, feeding pelagically or benthically, as needed for maximum energy gain primary prey source is mysids only feed on benthic amphipods when they reach a certain size F. Nicklin that does not slip through their baleen two or three years of heavy feeding can decimate the prey base and result in subsequent years of fallow foraging habitat while prey recovers https://whalelab.geog.uvic.ca/ R. Bonner Diet composition and feeding behaviour - Odontodetes Compared to Mysticetes, Odontocete diets are more varied in nature and species many fish species, small to large squid benthic invertebrates (shrimp, crabs, clams) marine mammals, including other cetaceans Hunting and capture vary by species some cooperate, other do not surrounding, herding tail smacks, head butts A. Van Ginneken  Dolphins herd fish Herding with mud plumes Beaching prey Baitball Science Photo Library  Killer whale hunting methods depend on prey type and location Tail smack to disable stingray (Baja California, Mexico) Carousel feeding on mackerel with tail smack (Norway) Harbour seal (Victoria, BC) Crabeater seal (Antarctic) Blue whale (Australia) Resident killer whales in the Eastern North Pacific may have a more varied diet than previously thought news article Rex Shutterstock Extremely varied diet of belugas (Delphinapterus leucas) Capelin Fisker Forum B. Logan NatureNews squid Arctic cod E. Svenson E. Svenson Adobe Stock DFO T. Sienicki crab bivalves shrimp Extremely varied diet of belugas (Delphinapterus leucas) Diet varies by age and gender Older adults: higher trophic fish & benthic species Calves: small fish & shrimp Yearlings: larger fish Subadults: mostly invertebrates Adult females: smaller fish Adult males: larger fish  GEOG 303 Conservation and Ecology of Whales Topic Three: Feeding Ecology & Ecological Niche Part Two: Ecological Niche and Roles of Cetaceans Ecological Niche The position of a species within an ecosystem, describing both the range of conditions necessary for persistence of the species, and its ecological role in the ecosystem. Ecological niche subsumes all of the interactions between a species and the biotic and abiotic environment. Polechová & Storch (2019) ##/## Join at: vevox.app ID: 117-239-196 Question slide What are some examples of factors that are included in the ecological niche of a species? ##/## Join at: vevox.app ID: 117-239-196 Results slide What are some examples of factors that are included in the ecological niche of a species? Important concepts related to ecological niche Fundamental niche: potential range of environmental conditions that a species can occupy Realized niche: the actual range they occupy Competitive Exclusion Principle: no two species can occupy the same niche in the same place or time Intra-specific competition: within a species Inter-specific competition: between two or more species The trophic pyramid Oceanic Ecosystems: Biomass & Energy Consumers Consumers Ocean Ocean Biomass Energy Producers Producers Janjua et al. 2013 Roman and McCarthy, 2010 R. Reidy The “Whale Pump” The “Whale Pump” Broader ecological implications of the “Whale Pump” Phytoplankton: Producers at the base of the food chain (photosynthesis) Phytoplankton require a steady supply of nitrogen, often in short supply in euphotic zone in the ocean. Cetaceans increase the nutrients required by phytoplankton, allowing greater primary production Carbon cycle: Phytoplankton absorb CO2 during photosynthesis, removing carbon from the atmosphere. Uneaten plankton and species that eat carbon up the food chain die and sink to the bottom, regulating the carbon cycle. Floating whale carcasses Remember the killer whale – blue whale video? Gasses caused by bacteria involved in decomposition cause the body to float Results in massive floating San Diego Fire Rescue nutrient-rich food source Attracts birds, sharks, fish Provides nutrients to nutrient-poor surface waters, which promotes primary productivity Whale falls Whale carcasses eventually sink to the bottom, going through three stages of decomposition: 1. Scavenger Stage: Large scavengers like hagfish, sharks feed on soft tissues 2. Enrichment-Opportunist Stage: Smaller detritivores (worms, crustaceans) feed on remaining scraps, oil, and decomposing tissues in the sediments Whale falls 3. Sulphophilic Stage: Bones (rich in oils) are colonized by bacteria During decomposition, bacteria produce hydrogen sulphide (H2S) Chemoautotroph bacteria use the H2S to produce energy, forming the primary productivity at the base of the food chain Some species have adapted to specialize in feeding off the nutrients in whale bones Broader ecological implications of decomposing whale carcasses Biogeochemical Cycles: Enhance nutrient transfer between surface and deep ocean (carbon, nitrogen, phosphorus, iron) Carbon Sequestration: Moves carbon to the ocean depths, removing it from exchange to the atmosphere Marine Biodiversity and Food Webs: Create small ecosystems that attract many diverse organisms, at the surface ad at deep depths. Create temporary feeding grounds for scavengers to apex predators GEOG303 Conservation and Ecology of Whales Mid-term test information Answer six (6) of ten (10) available questions, in paragraph form, worth five marks each, for a total of 30 marks. Test time: set for 60 minutes but you will have 90 minutes to complete it. No lecture afterwards; you may leave when you have completed and handed in your test. Example questions (these may or may not appear on the test): 1. Summarize the main evolutionary changes between Pakicetus and Ambulocetus. Provide details of the differences as cetaceans moved into the water. 2. Explain five adaptations that allow sperm whales to dive to incredibly deep depths. 3. Discuss the key characteristics of humpback (Megaptera novaeangliae) range, paying specific attention to migratory movements. 4. Discuss the differences in social structure and behaviour between resident and Bigg’s (transient) killer whales.