MARB 403 Lab 5

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Filter Feeding

A feeding strategy allows ind. to get large quant. of prey in single mouthful

Larger animals tend to be filter feeders:

large

travel long distances

more surface areas for feeding

energy storage (winter and migration)

small

higher energy content

Adaptations: baleen and modified teeth

Modified teeth for pinnipeds

Baleen

Right whales: 3m long and very fine (feed on small copepods)

3 types of filter feeding:

1. Skim feeding (Balaenidae)
2. Lunge feeding (Balaenopteridae)
   • take in 70% of bodyweight in water for each mouthful
   • Throat grooves allow throat to expand
3. Sediment straining feeding (gray whales)

Feed on small fish and crustaceans

Mysticetes have distinct migration patterns

• Gray whale has longest
• Linked with food availability

Short and Long Term changes in whale calling behavior:

We're noisy. Intentionally (sonar) and unintentionally (engines/propeller)

Low frequencies can be heard far away

North hemisphere has increased more than southern

Collisions are one negative effect

3 uses for whale calls

1. communication (cohesion, mating)
2. navigation
3. foraging

Any background noise (esp. low freq) affects all 3 of these

Increase intensity, rate, and/or duration; shift frequency; wait for noise to decrease

Investigate noise level and whale calls and how they've changed in the last few years

3 Classes of recordings

1. no vessel noise
2. just vessel noise or whale noise
3. whale and vessel noise

Results

3486 calls from 32 surface active groups (SAGs) from Bay of Fundy

2 types of calls (data collected in each class)

1. scream calls
   1. 623
   2. 1157
   3. 1015
2. up calls
   1. 25
   2. 244
   3. 149

Did ambient noise have any effect?

• min freq was lower in low-noise classes
• low-noise classes called less often

Discussion

High-noise did impact calling

• Decrease call rate (waiting until temporary reduction in background noise)
• Increase in call frequency (move out of interference band)

results were as a group, but does it affect individuals?

Species-wide response to increasing noise

Discussion

Making oceans quieter

• industry perspective: quieter means less energy wasted to making noise; more efficency
• raise awareness of cetaceans (everybody loves whales and dolphins!)