Marine Mammal Exam #3
How long do dugongs take to sexually mature on average?
17 yr
How long do cetceans take to sexually mature on average?
2-20 yrs
How long do manatees take to sexually mature on average?
3 yr
How long do pinnipeds take to sexually mature on average?
3-7 yr
How long do otters take to sexually mature on average?
4-7 yr
What is the exception to the rule on cetacean shedding ?
Belugas
What are some boundary types that can distinguish a population?
Biological - genetics and behavior Political - state laws, country lines Practical - large scale group that is protected by an agency
What is the kernel method and how it is used
Image a cut open jawbreaker with multiple layers surround the core. Each colorful band is a "kernel" and represents a different percent chance that you will find an animal or it's home range within the kernel.
What is an example of the density dependent trait.
In dugongs, if there is low abundance of animals and high availability of of nutritious food then the dugongs will become sexually mature sooner
What is a negative of genetic tagging?
It can be very invasive and it can potentially not have a lasting impact
How can genetic tagging be used in figuring out animal movement?
It can generate sex information and ID individuals
How can survey ships/aircraft aid in figuring out animal movement?
It is a way to go offshore and monitor the native or migrating populations
Describe Home Range
It is the area that encompasses all the area an animal uses in it's normal life
What decreases a populations size?
mortality and emigration
Describe Dispersal
movement from one area to another permanently
Describe Commuting
moving from one dense prey patch to the next in the same region
Describe Ranging
moving from one prey patch to another in a different region
How is the Minimum Convex Polygon Method used?
multiple animals are tracked and their siting locations are plotted. All points are connected and the home range is within the shape.
Why is home range assessed?
to compare among animals to see if there is a change that depends on season Identify critical areas for management
Why must pinnipeds stay on land to molt?
to mole they must send a lot of warm blood to their skin to create a new fur coat so if they were in the water most of their heat would be lost and they would potentially die
What are density dependent traits?
traits that dependent upon the abundance of the animals
How can animals movement be inferred through distribution patterns?
whaling records stranding records survey ships/aircraft passive acoustic population characteristics
When does the population experience the intrinsic growth rate?
when there is a small population size because there is reduced competition
What are some negatives about using the kernel method?
working in smaller inlets can be a challenge because in this method land mass is accounted for and must be removed from each kernel
Can time of day affect foraging movements?
yes
Do cetaceans shed?
yes
What does senescence mean?
menopause
what things are expected when a population reaches carrying capacity
1) increased juvenile morality 2) increased age at sexual maturation 3) decreased fecundity 4) increased adult morality
What are the assumptions of mark-recapture?
1) marks being used are unique 2) marks cannot be lost 3) All markings are recorded correctly 4) marking does not affect survival or future recapture ability 5) equal probability of capturing any individual in the population
What assumptions must be used when utilizing the line transect method?
1) sample represents populations 2) cannot miss animals on the transect line 3) animals do not move prior to detection 4) data is recorded accurately 5) observations are independent of each other
How is it that whales know where to go when migrating?
1) social learning - mom teaches the baby 2) juveniles travel together and migrate at different times then the adults 3) reduced predation is associated with groups
Why do animals move/migrate?
Adaption to patchy, unpredictable, habitat/environment
What are some factors that influence reproductive life history traits(Natality)?
Age of sexual maturity # of offspring per reproductive cycle Frequency of reproduction(gestation period) Reproductive Lifespan(senescence)
What are the benefits of mark-recapture?
Data can be used in multiple situations Movement patterns can be studied Life history patterns can be studied(reproduction and life span) can create a CMR profile
What dolphin is known for diurnal foraging movements?
Hawaiian Spinner Dolphin
How does an animal's movement vary depending upon the density of the prey patch?
High density - make frequent turns and turn sharply Low density - make straight paths that may be slightly curved
What are the different scales associated with animal movement?
Home Range Commuting Ranging Migration Dispersal
How is data analysed?
Minimum Convex Polygon Method and the Kernel Method
Do pinnipeds have to travel far to molt?
No
Examples of natural markings that can be used to identify species are.....
Sperm Whales - rare edge of tail fluke Right Whale - callosities Orca - patch pigmentation Dolphin - trailing edge of dorsal fin
How can animal movements be inferred from repeated observations of individuals?
Tags and branding natural markings genetic tagging telemetry
What does estimate counting mean?
a sample of the population is counted and then that number is extrapolated to represent the whole population
How can tags and branding be used in figuring out animal movement?
The tags can send signals as well and be identified if an animal is recaptured Branding occurs on pinnipeds and it leaves a mark that can be distinguished in photos
How can Passive Acoustics aid in figuring out animal movement?
They are able to listen to specific sounds to search for a species(usually large whales) HARP - high frequency acoustic recording program
What are time-area based closures?
They are areas that humans are not allowed to go into when interacts will affects animals the most
How can whaling records aid in figuring out animal movement?
They are detailed records from when whales were hunted and show the location of where they were move abundant for years
How can stranding records aid in figuring out animal movement?
They can reveal cause of death, size, etc and the sites of the strandings can be linked together to show a pattern of movement
How do belugas shed?
They will in the cold arctic waters so when it is time for them to shed they move to warmer, fresher water and shed off all their old skin and sea lice
How can population characteristics aid in figuring out animal movement?
This allows for genetic markers and can give information on contaminant or parasite loads
What happens if males and females mature at the same rate?
This is seen in non-competing species Usually the males will delay their maturity Seen in mysticetes and pinnipeds
How can natural marking be used in figuring out animal movement?
Various species have unique markings that allow for individuals to be identified because each individual has different markings
How is home range assessed?
marking(using photographs and branding) telemetry acoustic tracking(active or passive)
How can migration aid in an animal's ability to avoid predators and prevent disease?
When an animal is fasting all the parasites, bactieria and fungus inside their bodies has not food and this can potentially rid an animal of dangerous pathogens Predators can be avoided by moving to different areas that are not native habitat to the predators
How is a census different from an index count or a estimates?
a census involves counting every single animal in a population while a index count involves counting a sample of the population to create trend data
What is considered a population?
a group of interbreeding animals
How is mark-recapture used?
a sample is captured, then marked and released a second group is captured and the number of marked are recorded, the rest who are not marked are marked and released sampling is done multiple times Then the equation N = (N2/M2)*N1 to find total population size
When does dispersal usually happen?
after maturity to prevent interbreeding
What are breeding areas called?
aggreations
How is thermoregulation associated with migration
animals can move to areas with warmer/colder waters because most of them are limited to a range of temperatures that they can survive in.
How are animals counted?
census index count estimates
What group does not form aggregations?
cetaceans
What are the downsides of telemetry?
costly small sample size manatees can have the band entangled bolt through a dolphin's dorsal fin is highly invasive suction cup tags have a short attachment period
what is an example of small scale species temporal variation
diurnal spinner dolphins
What are pros of having a specific breeding area?
easier to find a mate safety in numbers
What is the predictability of an animal's where-abouts affected by?
features of their habitat oceanography
Why do males reach sexual maturity faster?
females, this is because males have an extreme competition for fertile females
What is the primary factory driving movement?
food
what are the big three life history charatrristics
growth maintenance reproduction
How long do mysticetes take to sexually mature on average?
in the middle of the 2-20 yr range
How can animal movement be monitored?
inferred fro distribution patterns of the group and repeated observations of individuals
How can telemetry be used in figuring out animal movement?
it is a way of attaching equipment to an individual that allows for information to be gathered like location, depth, etc. Can be used on ALL marine mammals?
What is the intrinsic growth rate?
it is the maximum rate of growth when no environmental factors limit population increase
Why is it thought that pinnipeds form aggregations?
it is thought that if an animal is successful in one breeding season at a specific spot then they will return to that spot to try and have another successful breeding season
How is mark-recapture different from line transect?
it is used with smaller populations and more information is gained on an individual
How is line transect counting completed?
it surveys large areas line are systematically placed, then each line is traveled by a boat or aircraft, each animal seen while the ship/aircraft travels is counted. Trigonometry is then used to find the distance the animal is to the transect line
what is related to large body size
long lifespan slow growth delayed sexual maturity produce few offspring spend large amounts of time and energy in offspring
Which gender matures faster?
male
When do males and females sexually mature in sperm whales?
male 20 yrs, females 10 yrs
How does the age of maturity differ in marine mammals versus in terrestrial mammals?
marine mammals mature faster because they are larger on average than terrestrial mammals
How is estimate counting completed?
mark-recapture and line transect counting
What are some population/demographic parameters?
natality mortality Immigration and Emigration(Dispersal)
What increased a populations size?
natality and immigration
Do marine mammals usually show senescence?
no
Is it common for females to mature later than males?
no it is very rare
How long do orcas and sperm whales take to sexually mature on average?
on the upper end of the 2-20 yr range
How is telemetry different between species?
pinnipeds - glued on fur otter/polar bear - collar manatee - band around tail fluke dolphin - bolt through dorsal fin(EXTREMELY INVASIVE) cetaceans - suction cup tags
Where do animals move to?
places with excess resources that can handle the animal during various activites
Why is animal abundance so variable
prey distribution, availability, and abundance
Describe Migration
repeated, regular, large-scale movement that is usually linear
What cetaceans are the exception of the rule about aggregations?
right whale, humpback whale, and gray whale
What species might show senescence?
short-finned pilot whales, orcas and maybe sperm whales
What is a negative of the minimum convex polygon method?
the shape of the home range is highly dependent on sample size because outliers are used
What does bimaturism mean?
there is a difference between the sexes
What happens when females mature faster than males?
there is a higher rate of fecundity because a female with a larger body size has a higher reproductive success
What do manatee males have the ability to do?
they can make sperm sooner
What happens when a pinniped molts?
they lose all of their fur, which comes off in large patches
How does a cetacean shed?
they lose their epidermal layer continuously(aids in aerodynamics)
what does it mean if an animal moves based on diurnal temporal variation
they move based on the deep scattering layer that moves to the surface at night to feed
What is special about breeding movements?
they show a strong seasonal trends most have a high fidelity to a breeding area
Why should animals be counted?
to better understand rarity of species, for conservation, animal abundance, trends in population size, and life history characteristics
