Marine Mammal Ecology

• Ecology : An attempt to describe and explain the patterns of distribution and abundance of organisms. These patterns reflect the history of complex interactions with other organisms as well as the environment.– Marine mammal ecology is had to get data on. – Marine mammals live in the ocean, which makes

everything harder

• Marine Mammal Protection Act prohibits many techniques typically used to study animals

Marine Mammal Ecology

• Distribution Ecology attempts to explain the restricted and generally patchy distribution of species– Marine mammals inhabit almost all

marine environments, including estuarine and even freshwater

Fig. 45-1, p.800

clumped

nearly uniform

random

Fig. 45-2a, p.802

Fig. 45-2b, p.802

Fig. 45-2c, p.802

Factors affecting the distribution of marine mammals

• Habitat• Biology: including productivity (food)• The distribution of predators• Demography of population

– Size– Sex ratios– Age– Reproduction

• Species Adaptation: Morpholigical, Physiological, Behavioral

• Human effects: Disturbances, Pollution

Fig. 45-17a, p.815

Fig. 45-17b, p.815

Fig. 45-18, p.815

Methods to study Marine Mammal Distributions

• Surveys: Counting who is where when– Shore based, especially with pinnipeds– Ship based, more common with cetaceans

• Telemetry: Radio tags– Use VHF radio waves to keep track of the animals– Also link the tags to satellites, which only works when the animal

is at the surface

• Seasonal Movements: – Migratory- Many marine mammals move seasonally in order to

take advantage of seasonally abundant food sources– Non Migratory

• Dispersal: movement of an individual from its birth place to subsequent breeding ground

Radio Telemetry

Pinnipeds

• Must periodically leave the sea in order to breed, birth or molt– Either land on shore or ice

• Changes in the ice pack will definitely alter their distribution

• Great variability in seasonal distribution among the families.

• It seems that phocids tend to be more migratory