Lecture 9 Flashcards
(21 cards)
migration and movement are:
hallmarks of marine mammal behaviour
what is foraging?
search for resources (ie. food, conspecifics (including mates), and space) within a patch
what is a patch?
an area within which resources are randomly distributed
what is commuting?
movement between adjacent patches
what is ranging?
movement between regions. after searching patches in a region, an animal then moves to another region, spatially separated and defined by a different local set of oceanographic conditions
what is dispersal?
permanent movement from one area to another
what is foraging for marine mammals?
- foraging animals rely on predictable resources at a specific place and at a specific time (scale)
- resource variability requires movement tactics that allows an individual to maximize its fitness
what’s the difference between a constant environment and a high-variance environment?
- constant: an individual is likely to find food on most days
- high variance: an individual may have difficulty finding food from one day to the next and for considerable stretches of time. This animal is essentially living in an energy sink environment with few areas of energy sources. unless significant energy stores are available, that individual is going to run out of energy
what is home range:
captures the area that each marine mammal utilizes, or covers during its normal activities, including feeding, traveling, resting, and breeding
what are core areas?
represents sites of greater ecological significance to the animal and therefore are a better representation of preferred foraging sites (70% of their time is spent in the defined area)
what is the relationship between home range and body size?
- marine mammals, by virtue of their large body sizes, require large home ranges
- given that resource distribution is variable in space and time, some home ranges are enormous (pygmy whale home range = ~450,000km^2)
whereas others are relatively small (harbour seal home range = 10km^2) - as home range increases in size, an individual experiences spatial and temporal environmental variability and contaminant exposure variability
what is migration?
- regular, repeated, and large-scale movement between different sites of the home range
- the difference between migration and other large-scale displacements is that migration consists of persistent linear travel not distracted by resources. the goal is to move between sites/areas each serving in a different life history role
- these destinations for marine mammals are areas for feeding, breeding, birth, lactation, and molting
what is telemetry used for?
- telemetry studies have suggested that areas with a higher frequency of deep dives suggest intense, localized feeding behaviour
- whereas hauling out for extended periods reduces energy loss to locomotion. therefore most of the stored energy can be used for reproductive activities and metabolism
how do we characterize a marine mammal’s home range?
- telemetry (tagging)
- flipper tags (mark recapture, look at population dynamics)
- visual observations
- acoustics (hydrophones)
- e-DNA
- indigenous knowledge
what physical/chemical characteristics affect bioaccumulation pathways and processes?
- log Kow
- molecular size
- molecular structure that makes molecules more or less prone to biotransformation enzymes (eg. location of H atoms on PCB molecules)
what biological factors affect bioaccumulation pathways and processes?
- energy/food requirements
- reproduction
what are individual-based models?
- The individual-based model puts all these processes together into math equations that can be solved repeatedly to simulate the lifetime exposure, assimilation and loss of chemicals
- These equations consider the animals’ life history, growth, energy requirements and food intake, chemical intake/absorption and elimination
- For females, a submodel can be added for fetal growth, followed by a nursing
calf that gets its food energy from milk which, in turn, requires greater maternal food intake to enable milk production
what is contaminant transfer by lactation and Chemical Mass Transfer?
Chemical mass transfer is a function of:
- length of lactation, milk volume, and fat content
- chemical partitioning to milk (milk:blubber ratio)
- maternal blubber dynamics
- maternal contaminant burden and change over time
what are the biomagnification factors for killer whales?
- biomagnification factors vary with sex, age, and reproductive activity
- adult male BMF = 30-60
- adult female BMF = ~20
- juvenile BMF values are highly variable, depending on: birth order and interval, duration of nursing, age and growth (dilution)
how are contaminant levels related to population dynamics?
- mortality, predation
- immigration, emigration
- maturation (males vs. females)
- juveniles (biodilution)
what is a population-based bioaccumulation model?
- adds annual summaries of contaminant fluxes to a population dynamics model
- can track changes in contaminant burdens in a population across generations
- output matrix for 2 sexes x 50 age classes x 60+ years
- potential to add effects of contaminant burdens on mortality and production from dose-response relationships
