Marine Megafauna: PDF

Overview Marine megafauna are often thought of as large oceanic animals. Important role in marine ecosystems: most marine megafauna are keystone species impact due to diet size abundance...

Overview Marine megafauna are often thought of as large oceanic animals. Important role in marine ecosystems: most marine megafauna are keystone species impact due to diet size abundance distribution not megafauna, mega biomass Marine animals need to consume 10% body mass per day Ectothermic animals get their heat from outside Homeothermic animals regulate their own body temperature Ectothermic herbivores (iguanas, sea turtles): reptiles impacting seagrass Ectothermic meso/ apex predators (sharks, tuna): top down effect impacting other animals and where these other animals are going to eat Homeothermic herbivores (dugong): maintain plants, slow moving Avian predators (northern gannet, king penguin, short tailed shearwater) Mammalian predator (cetaceans): harvesters like blue whale vs hunters like killer whales Mammalian harvesting predators (pinnepeds): Pinnepeds impact terrestrial ecosystems as well such as defection on land Mammalian harvesting predators (sea otters) Overview 1  Mammalian predators Polar Bear) Coastal species River otters, Falkland steamer duck) Trophic importance Substantial biomass due to large body size, large populations, or both. High food intake, endotherms have high metabolic rates As apex predators they impact ecosystem - “trophic pyramidˮ Marine mammals: Seabirds: Overview 2  Potential for fisheries conflicts Operational interactions - killer whales have learned to steal fish on the line Direct/ Indirect competition - fishermen believed to be in direct competition with one predator, but marine food webs are complex Monitoring Ocean Health Marine megafauna can be used to monitor ocean health Behaviour and reproductive success indication of prey availability & distribution Pollution indicators - contaminants concentrate up the food chain Role in Terrestrial Ecosystems Allocthanous transfer of marine nutrients - guano and prey debris alter soil nutrient loads. Increases primary productivity with a cascade impact on ecosystem Affecting plant community as soils may become too acidic and alter climax species (e.g. tussock) Run-off impacts on marine ecosystem Physical destruction of vegetation/habitats due to trampling & nest building Harvesting Food source for native communities & traditional hunts e.g. Inuit seal hunting Overview 3  Commercial resource IWC Whaling Moratorium 1982 Norway, Iceland and Japan still whale Ecosystem impact of recovering population is unknown Ecotourism Whale watching Swim with dolphins, Seals etc. Penguin watching Also nesting sea turtles, whale sharks, white shark cage diving etc. Overview 4  Pinnipeds Three extant families  Odobenidae (walrus) 1 sp 2 sub-spp)  Phocidae (true seals) 19 spp  Otariidae (fur seals, sea lions) 1417 spp Fossil record indicates greater previous diversity Commonalities Long lived animals (longevity 15  25 y; walrus  40 y) Breeding and offspring provisioning on land/ice Annual breeders (some exceptions) Highly synchronous in dense colonies (some exceptions) Polygynous Single offspring All represent substantial biomass consumption in their ecosystems Diferences Integument phocids – short pelage otariids – longer, dense pelage of fur (fur seals) or hair (sea lions) Size (implications for life history traits) phocids mean mass: 45  3000 kg otariids mean mass: 64  500 kg Pinnipeds 1  Reproduction and lactation strategies phocid – capital breeders (some exceptions) otariids – income breeders Evolution Competing hypotheses for pinniped evolution:  Monophyletic, all extant groups evolved from mustelid (weasel-like) ancestor  Diphyletic otariids and odobenids evolved from ursid (bear-like) ancestor and phocids from mustelid ancestor Pinnipeds 2 Pinnipeds 3  Fur seal - Sea lion differences Fur Fur seals put on a lot of fat for empty storage. The thick fur Hair contains trapped air that keeps them warm in the water. However, it Use fat as storage. Can dump heat means they cannot regulate or through the skin. release their heat Size Ecological and life history implications Pinnipeds 4  Males are larger accordingly to sexual selection, not according to ecology. Skeletal adaptations Reduction in limbs overall Enlarged scapula and reduced pelvic girdle Pinnipeds 5  Thermoregulation Many species live in cold water environments, as where they are depends prey distribution there is usually more prey in cold water. Thermal conductance 25 times greater in water than in air Many species also endure cold ambient temperatures. Two strategies of thermoregulation:  Fur a Fur seals have two layers of fur i long guard hair (traps layer of air) however not in natal coat! ii Dense short under hairs - density of follicles x 50 greater than in terrestrial mammals b Sea lions only have one layer of fur, not as dense as fur seals i may rely more on blubber  Blubber - thick layer of subcutaneous fat Fur Blubber  Insulation layer does not change with depth  Provides smooth contour shape Benefits Not positively buoyant to body  No grooming or moulting  Also acts as energy storage  Insulation layer reduced with increasing depth Disadvantage  Must groom regularly Positively buoyant  Annual moult (metabolic/nutritional cost) Common problem with thermoregulation is that losing heat is complicated, causing climate change to put them at higher risk for predation. Management of O2 stores for diving Storage: Pinnipeds 6  Large myoglobin stores Large blood volume (x 1.5  2.0 Large red blood cells Higher haemoglobin content High myoglobin content Bradycardia and blood shunting Utilisation: Aerobic dive limit Cardiovascular adaptations Bradycardia - dive response Diet and foraging ecology Diet Diet of seals consists primarily of fish and cephalopods, leading to fisheries interactions. Their diet corresponds with their dentition, as they have prominent canines for seizing prey: carnassial premolars which reflect their Arctoid carnivore ancestry. Exceptions: Crabeater seal has a 90% krill diet Walrus, with continuous growing canine tusks, drudge the muddy sea floor sucking flesh out of shells Foraging Pinnipeds 7  Fundamentally different diving behaviours between foraging modes revealed from dive behaviour data loggers and satellite/ GPS tracking. Differences in: Dive profiles Swimming speeds Amount of diving Temporal and spatial distribution of dive frequency and depths Foraging Areas can vary from benthic to epipelagic depending on abundance of prey. In fact variations in marine productivity impact pelagic foragers. Pelagic hunters forage in upwellings, fronts etc., areas of high primary productivity where schooling fish, krill and squid congregate. Benthic hunters go to areas they have foraged in previously. What potential threats do these different foraging strategies experience?? Pelagic: oceanic enviro-variability (pelagic, less so benthic) Benthic: Sea floor degradation i.e. benthic trawls, dredging, etc. Pinniped reproduction Limitation to marine existence Pinnipeds ancestors would have entered oceans to exploit resources more profitable than on land. However, unlike cetaceans and sirenians, pinnipeds still Pinnipeds 8  need to haul-out for mating and nursing. This has shaped their reproductive patterns, mating systems, lactation and foraging ecology. They usually reproduce on islands or at the bottom of cliffs as protection from predators and as it is the closest to their foraging habitats. Mating systems Pinnipeds can be highly polygynous to serially monogamous, available breeding habitat will determine female distribution and mating system. As their breeding habitat is not available all year round there are limited suitable breeding spaces. Breeding sites will also depend in relation to resource distribution, particularly importantly for Otariids. There are three main types of breeding habitats:  island (or land)  fast-ice  pack-ice Polygyny Animals congregate at a central place and time to reduce predation risk, coinciding giving birth with mating. Synchrony in breeding leads to competition to acquire most mates, harem formation in order to quickly access large numbers of oestrus females. This leads to sexual dimorphism, preference of larger males. Sexual dimorphism Competition for females leads to physical conflicts. Bigger males have conflict advantage (large size selected trait), driving sexual dimorphism. Pinnipeds display the most extreme sexual dimorphism of all mammals. As few as 10% of males can get 90% of matings. Antarctic fur seal males are x5 larger than females and Southern elephant seal males are x10 larger than males. Annual breeding Pinnipeds 9  Single pup Post-partum oestrus (varies among families) - ovulation and corpus luteum production that occurs immediately following the birth of the young Delayed Implantation or Embryonic Diapause Blastocyst (fertilised egg) does not implant in uterine wall for 34 months Active gestation of 89 months Implantation triggered by progesterone surge Why have delayed implantation? Gestation lengths phylogenetically/size related (i.e. evolutionary “hard- wiredˮ to some degree) Enables 12 month cycle Delays commitment to gestation Implantation appears condition dependent (after annual moult) Capital breeders acquire and store energy for breeding before the start of the reproductive season, whereas for income breeders reproduction is financed using current energetic income. Lactation patterns Capital Breeders: Pinnipeds 10  Single long trips Economical foraging strategy Large size favoured Income Breeders: Multiple short trips Expend high energy to obtain resources Pup growth not efficient Otariid pup growth Pups must fast while mother is away Females must deliver resources for growth PLUS fasting Female must fast while ashore Delivery of large amounts of nutrition very quickly How might environmental variations impact the different foraging patterns? Pinnipeds 11  Pinniped distribution and abundance Current distribution and abundance may be an artefact of recent human activities such as the sealing era exploitation 18th  20th centuries), modern fishing industry and other human interactions. This has caused a loss of breeding habitat due to development, whaling impact on ecosystems, killer whale prey switching etc. Odobenids (walrus) Pacific walrus Odobenus rosmarus divergens): 200,000, decreasing Atlantic walrus O. r. rosmarus): 14,000, trend unknown Laptev population: not fully recognised as sub-species Pinnipeds 12  Phocids Found in north and south oceans. They are pelagic foragers recovering from past hunting i.e. Monk seals have been impacted by hunting and fisheries interactions. Caribbean monk seal extinct since 1952, Mediterranean monk seal Endangered), Hawaiian monk seal Endangered) Southern elephant seal Circumpolar distribution Four main stocks: Pinnipeds 13   Kerguelen/Heard Islands  South Georgia  Peninsula Valdez  Macquarie Island Keystone species (top predator) Major influence on marine ecosystem Hunted for blubber in 18th & 19th centuries, drastically depleting all stocks which mostly recovered early 20th century First regulated harvest on South Georgia (south Atlantic) until 1964, now steady population Late 20th century declines in Indian-Pacific population with a 50% decrease between 195085 When decrease began, nothing known about the species so the cause of decrease not well understood, current thinking is the Ocean Regime shift Decline appears to have stabilised at some locations, suggesting multi- decadal ocean regime shift Otariids Found in North Pacific ocean, as well as more in the temperate and sub antarctic region All otariids have been hunted to near extinction during commercial sealing era 18th and 19th C for production of felt hats and blubber oil. Most fur seal species have or are recovering with the greatest increase seen Antarctic fur seal. There are now more than pre-sealing times (known from damaged moss beds), this may be due to a lower presence of baleen whales causing little competition for food. However, several species have experienced declines recently such as the steller sea lion or the northern fur seal. These declines may be result of combined factors including fisheries collapse, killer whale predation (prey switching), and ocean regime shift. Pinniped conservation and management Pinnipeds 14  Conserve  Protect and maintain Manage  Assess, develop a strategy, do something (could be do nothing) Management issues include: Lone seals - leads to long crowd control with long hours and large budgets Tourism - interest and impact Pollution - ocean contamination Disease - populations in danger Endangered species Species diversity – endangered prey/competitor Harvesting - still occurs in some countries Fisheries conflict - entanglements, operational interactions, fish farms, direct/indirect competition, both elicit rogue action by fisherman Climate change/fluctuations - impacting food availability, storm surge impacts on breeding sites Industrial development - seafloor infrastructure/construction, shipping disturbances Pinniped research methods Diet Scats (old school but low cost simple) - easy to collect (unlike cetaceans), has biases but can be accounted for Stable isotope analyses - widely used, requires small samples (mg), different tissues = different time spans e.g. whiskers multi-year trophic information Fatty acid signature analysis - provides more information, can identify prey species Animal-borne video data loggers Population estimates Pup counts - direct, aerial (planes/drones), multipliers for total population Body condition estimates Pinnipeds 15  Direct weighing/measuring Drone surveys At-sea movements, habitat use and behaviour GPS data loggers Dive behaviour data loggers Habitat suitability models/agent-based models Pinnipeds 16  Seabirds Seabirds are birds living in and making their living from marine environment including coastal areas, islands, estuaries and wetlands. They spend most of their lives at sea and can spend weeks to even years at sea in one stretch. They come ashore to breed and moult. 250 of 8,500 bird species are adapted to live near or in the sea. Encompass several avian orders: Procellariiformes 92 albatrosses, petrels, storm-petrels, fulmars, shearwaters Pelecaniformes 67  pelicans, frigatebirds, gannets, boobies, cormorants Sphenisciformes(17) -penguins Charadriiformes 350  skuas, jaegers, gulls, terns, auks, guillemots, puffins (a very varied group! Anseriformes and Gaviformes – eider duck, red-throated loon Procellariiformes Pelagic Seabirds 1  Includes largest (wandering albatross) and smallest European storm-petrel) seabird. They are excellent fliers/gliders and use the ground and burrow for nesting Also known as ‘tubenosesʼ for tubular nostrils atop beak – salt gland excretion, olfaction and pressure sensor Some local extinctions with many more endangered Pelecaniformes Pelagic and coastal Sphenisciformes Pelagic and coastal Seabirds 2  Charadriiformes Pelagic and coastal Alcids Efficient underwater swimmers (like penguins) but can also fly. Mostly burrow- and cliff-nesters Some species are extinct Great Auk) and some endangered - i.e. marbled murrelet nests in ol growth forests of Pacific Northwest threatened by logging Seabirds 3  Terns Mostly coastal but include longest distance migrants of all species Skuas and jaegers Very aggressive omnivores and predators - known as “hawksˮ or “vulturesˮ o the sea Anseriformes and Gaviformes Coastal - not “trueˮ seabirds but have important ecological impact in specific marine habitats Life history traits Sea birds have extreme life-histories : dramatically different life histories to terrestrial birds, they are k selected (terrestrial birds are r selected) so have low reproductive rates, delayed onset of reproduction, extended chick-rearing periods and as a consequence increased longevity. Seabirds 4  Why are they so different? Morphological and physiological adaptations for feeding in marine environment Shaped by environmental conditions at sea (food availability) and on land (nesting habitat and predator avoidance). Both which act to determine ecology of seabirds because unpredictability of food distribution (effect of sea) and finding suitable nesting habitat near reliable food sources (effect of land). Thought to be mediated by energy-limitation as there is no post-fledging parental care Diets Forage on variety of fish, cephalopods (squid, octopus, cuttlefish), planktonic crustacea (krill, amphipods etc.) and carrion of marine mammals. Varied foraging techniques, they can hunt alone or as packs and can have multi-species feeding flocks/frenzies Foraging Seabirds 5  Surface feeding Storm Petrels Flit back and forth, lowering the feet and pattering the surface of the water Dipping head down to feed on zooplankton and small fish Frigatebirds skim the surface at full speeds and with lowered head, plucking food from the surface layer method facilitated by long neck and long, sharply hooked bill Kleptoparasitism! Terns Pick off fish or squid that are running away from larger predators, Pattering, plunging or catching flying fish in the air. Surface feeding with swimming Feed by sitting on the surface or forcing themselves below (pursuit diving) Albatrosses and Shearwaters Seabirds 6  Feed mainly on fish, squid, cuttlefish, crustaceans and offal, but also eat jellyfish. Usually feed at night by dipping their heads into the water, though they sometimes can plunge dive (up to 50 m in some spp) they feed at night because many fish and zooplankton surface at night. Nomadism allows these birds to take advantage of rich, but widely separated food sources. Factors influencing seabirds foraging areas Same as for marine mammals: Upwelling regions Eddies/fronts Sea ice cover Additional factor is wind (direction and strength), not for penguins (of course..) Dynamic soaring flight Plunge diving Seabirds 7  Gannets and Boobies Heavy birds, they may begin dive with either wing beats, or just falling Go at most 10 m deep and last for less than 10 seconds Air sacs cushion against the impact and occluded nostrils prevent water up the nose, reinforced bills Can continue as pursuit diving Shallow plunge diving Pelicans, terns, gulls Pursuit diving from surface Hard to be efficient flyer and diver puffins, auks, guillemots cormorants and shags – not very waterproof feathers, reduces buoyancy but thermoregulation too limits foraging range Most efficient are the penguins swimming is expensive and slower than flying, reduced foraging range but can dive through water column depth as foraging zone i.e. Emperor penguins can dive 500 m and 20 min Reproduction, distribution and abundance Colonial breeders 95% of seabirds breed in colonies, much higher rate than non seabirds High degree of philopatry - breeding where you were born Some colonial species breed in small groups or separately Some mixed species breeding sites due to limited about of nesting locations Seabirds 8  A colony is a group of breeding individuals which associate together and maintina association to an extended greater than expected by change. It can vary size and forms from few individuals to millions Advantage of colonial breeding include: Shortage of nesting space Predator defence strategy - safety in numbers Social stimulation - improves sexual selection Information centre hypothesis - individuals can observe where others forage Disadvantages of colonial breeding include: re-use of sites encourages parasites (e.g. ticks) Intraspecific competition and agression Density-dependent effects Potential adverse effects of predators (attraction) Greater opportunity for cuckoldry EPCs) Exerts a constraint on recruitment and formation of new colonies Competition for food (max. colony size related to foraging range) Breeding habitats Most seabirds nest on cliffs Advantages of cliffs : few predators Disadvantages: eggs can roll off, many species have pear-shaped eggs to avoid rolling off ledges Seabirds nest on of beneath flat ground Advantages: More stable temperature, wind facilitates arrival and departure, few predators Disadvantages: can get flooded during rain Seabirds 9  Clutch size Number of eggs laid in a single brood by a nesting pair of birds Seabirds are mostly annual breeders Clutch size is around 12 and is related to life history strategies, larger clutches = shorter lifespan Chick provision strategies For most species both parents incubate - central place foraging for self and chicks, limited by how long partner can sit and nest or how long egg can survive cold. Parent may consume different prey to chicks Carrying food to nest is not feasible when flying great distances. Regurgitates through stomach oils are also limited by stomach size and mass that can be transported. Stomach oils in Procellariform seabirds - selective retention of lipids and non-aqueous phase Procellariform dual trip strategy:  short – gathering food for chicks  long – regaining self-condition Post breeding dispersal/ Migration Freedom from offspring provisioning enables more distant resources to be exploited. Seabirds 10  Residents - individuals remain around breeding colony, make longer foraging trips Nomadism - individuals disperse from the colony in various directions and have no specific non-breeding area Partial migration - some individuals remain resident, others move to a variety of areas for non breeding period True migration - all individuals from a colony move to the same area for non breeding period, locations can vary between colonies Arctic tern migration is the longest known migration of any animal Threats to Seabirds “Endangeredˮ criteria: 50% reduction over the last 10 years or three generations, whichever is the longer based on (and specifying) any of the following: Area of occupancy  500 sq km Population 2500 mature individuals Probability of extinction 20% in 20 years Populations have evolved in equilibrium with natural mortality. Factors that are anthropogenic in origin/level are ultimately reducing population size unnaturally by reducing survival and/or breeding productivity Marine threats Fisheries related - bycatch through gill netting and long lining Oil pollution Toxic effects Hypothermia Starvation Possible reduced immune function? Possible starvation from reduced productivity? Varies in extent from single birds to 500,000 Exxon Valdez spill in Alaska 1989 Seabirds 11  Penguins and alcids are the most susceptible seabird group to being oiled Climate change Water temperature change - general increase causing productivity decrease marine heatwave events Miss match of resources Competition for food - competition from commercial fisheries and cumulative effects of climate change Reliance on scavenging / discards Terrestrial threats Predation - natural and human, introduced/ invasive predators as well as natural predators Habitat destruction loss of breeding sites erosion Seabird research method Diet analysis techniques Stomach contents (terminal sampling) Regurgitates albatross petrels/shearwaters gannets/boobies stomach flushing penguins petrels, shearwaters pellets/discards Seabirds 12  cormorants Alcids gulls photographic puffins/terns genetic analyses of faecal samples combination of techniques give best information Tracking at-sea movement VHF transmitters – required triangulation and following Geo-locating light sensor GLS loggers Satellite telemetry GPS tracking Population estimates Passive acoustic monitoring - for burrow nesting species Drone surveys Satellite images – for surface nesting species Nest habitat suitability modelling Used for burrow-nesting species where aerial surveys (drones/satellite imagery) not useful Use of Wilsons Prom survey data Environmental variables (slope, aspect, vegetation etc.) Estimated number of burrows similar to areas with previous estimates Seabirds 13  Cetaceans Class Mammalia, Order Cetacea, Suborder Odontoceti 10 Famlies, 70 spp), Suborder Mysticeti 4 Families, 13 spp) Massive size range Odontoceti 70 extant species Identifying characters Toothed Single blowhole Asymmetrical skull Echolocation Cetaceans 1  Mysticeti 15 extant species Identifying characters Baleen Two blowholes Symmetrical skull No echolocation Morphological and physiological adaptations Skeletal - cranial Extension of premaxilla and maxillae posterior and dorsal shift of nares Cetaceans 2  Asymmetry in Odontocetes isolation of auditory system for sound reception air sacs, fatty canal to auditory bulla Increase in size Skeletal, large size Heat loss = higher metabolic rate consumption  O2 consumption so less time below surface to forage Increase in body size means decrease in surface area to volume ratio Cetaceans 3  Dentition Heterodont dentition going to homodont piscivorous dentition (interlock) Polydont dentition = increased # of teeth Mammalian norm max is 44 heterodont, marked reduction in teeth to 0 Or replacement of teeth with baleen - pleated throats in rorquals enable large volumes to be filtered Acoustic Mysticetes Low Frequency Sounds (infrasonic) Deep Sound Channel facilitates LFS propagation “Perceiveˮ marine environment Migration corridors Feeding grounds Breeding areas Higher frequency for communication Odontocetes whistles of mid- to high-frequency echolocation – ultrasonic (very high frequency) Cetaceans 4  Blubber Body contouring, reduces drag while swimming Energy storage Provide water Insulation Stratified Fatty acids vary in layers Inner most labile, outer least Diving and pressure Can collapse lungs at depth to prevent nitrogen absorption and maintain continuous partial pressure of O Aerobic dive limit time animal can stay submerged using aerobic metabolic pathway Minimising anaerobic metabolism - lactic acid build-up needs time to clear Cetaceans 5  The more blood volume, more oxygen can be kept in the bloodstream on it the muscle. Allows for oxygen storing capacity outside the lungs Reduced oxygen utilisation through cardiovascular adaptations (bradycardia - dive response), hypo metabolism Diet, foraging ecology and distribution Odontocetes Delphinids most well known from direct observations and stomach samples from strandings/collections Primarily fish and squid - consistent with dental morphology, mostly small- medium prey Exceptions sperm whale eating giant squid and killer whales – other marine mammals like penguins Odontocete foraging Fast moving schooling prey or feed on single prey (large relative to predator) Both require high sociality, highly evolved system of working together to find and capture prey Cetaceans 6  Mysticetes Eat mainly krill and small schooling fish Capture such small prey because of large body size needs large food intake Baleen plates allows for “filteringˮ large volumes of water Targeting concentrated prey increases efficiency, krill can form large swarms (plankton....). Concentrating swarms crucial for schooling fish to increase efficiency Cetaceans 7  Use bubble netting which implies a high degree of sociality Factors influencing prey distribution Prey distribution impacts predator distribution, zooplankton are central to pelagic food webs. Food gets concentrated, prey is not homogenous but patchy so there is a necessity to locate optimal prey patches Global currents Coastal upwelling (therefore bathymetry) Ekman transport Fronts, temperature and salinity discontinuity Eddies wind driven circulation patterns that trap nutrients Cetacean Reproductive Patterns Odontocete – prolonged development Cetaceans 8  Mysticete – rapid development Short period of dependency Gestation is not particularly fast Breeding, births and weaning tied into seasonal food supply and migrations Reproductive cycle linked to migrations Feed in polar regions Fast while migrating and during gestation and early lactation Migrate for thermoregulatory advantages and predator avoidance Threats to Cetaceans Noise pollution Boat strikes Fisheries conflicts/mortality Genetic isolation: post-whaling recovery of populations complication by geographic segregation. Potential consequence - evidence of hybridisation between species Climate change impacts on prey availability  Oceanographic alterations to prey abundance and distribution Mysticete whales – polar sea ice cover = zooplankton abundance Odontocete whales – fish/squid distribution Research methods for cetaceans Cetaceans 9  Practical problems: Natural habitat is vast, finding the animals is challenging Distribution is patchy and rapidly changing They spend most of their time under the surface Large body size Most information has been collected from commercial whaling, by-catch and stranding. Many information has also been collected during captivity Conservation/management requires information on foraging ecology, behaviour, distribution and movements and factors influencing these in free- ranging animals A lot of more recent research is conducted from small boats involving: photo ID, behavioural observations and movements, survivorship/demographics. Although this is very useful for some species it is limited for others, research boats and labour costs can be prohibitive so cheaper alternatives are needed - use of ecotourism boats? Habitat suitability models - register presence and absence Tracking studies Behavioural studies Stable isotope analysis to study diet - isotopic enrichment of 15N/14N and 13C/12C goes up the trophic levels Fatty acid signature analysis - fatty acid composition of marine prey is unique at species or genus level, analysis of “signatureˮ in predator is related to prey. blubber stratified – reveals seasonal patterns Genetic scatology - genetic primers used to scan faecal remains for various potential prey types Molecular studies - population genetics Aerial surveys - presence/ absence of species, abundance estimates, behaviour/ activity Passive acoustic monitoring - hydrophone arrays recording animals passing by, allows for population monitoring Cetaceans 10  Use of drones  Ability to approach whales with minimal disturbance, allows for disease monitoring, body condition estimates and photo ID. can collect exhalation and stufy DNA/genetics as well as hormones. Aerial surveys for population assessments Cetaceans 11