Dolphins and Whales Final

Cetaceans don’t have

vocal chords

How do cetaceans produce sound

phonic lips

What is a good inducer of sound?

Fat

Echolocation

method of producing sound that bounces off prey and comes back to the cetacean

Who can echolocate?

Sperm Whales and Delphinidae

Do both odontocetes and mysticetes whistle?

Most odontocetes whistle, mysticetes do not

What is a signature whistle?

a whistle that is considered their name

What can whistles also indicate?

mating or feeding

Who produces low frequency tones?

Mysticetes

What sounds do humpback whales make?

They produce mid-frequency “songs”

SOFAR

Sound Fixing and Ranging Channel: a naturally occurring ocean “channel” that allows sound to carry great distances

Who sings the humpback songs?

Only the males and they can determine health and can migrate around the world

What are acoustic clans?

Killer whales have acoustic clans and they determine these off sound. Different clans avoid each other

Marine Mammal Protection Act (1972)

Controlled by the Department of Commerce → NOAA → NOAA fisheries → office of protected resources

Optimum Sustainable Population (OSP)

the number of animals which will result in the maximum productivity of the population or the species, given the carrying capacity

Potential Biological Removal (PBR)

the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its OSP

Take

as defined under the MMPA means “to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill marine mammals”

Level B Harassment

potential to disturb

Level A Harassment

potential to injure or kill

How is the head chosen based on MMPA?

head is chosen by less biased groups (e.g. National Academies of Science or Smithsonian) and head must be aware of stock situations, if problems arise, they tell agencies to step in

Who grants permits under MMPA?

all permits are granted by NOAA

Permits: Directed Takes

for science (level A harassment), general authorization for level B harassment, entertainment facilities, enhancement of species, photography or filming, handling for stranding events

Permits: Incidental Takes

fisheries with by-catch or cetaceans and activities that could harm

Permits: Cetacean Parts

if moving between countries

Endangered Species Act (1973)

to prevent extinction, also includes habitat for protection

Magnusen Stevens Fishery Management Act

not directly related to cetaceans but protects the fish cetaceans eat

Pelly Amendment

if a country is not protecting a species to the level the US is or wants, the president can put a trade embargo on that country until the problem is fixed

CITES

Convention on International Trade of Endangered Species: only world wide organization for the control of illegal wildlife movement

Overfishing

93% of the world’s commercial fish stocks are already fished at maximum levels or are overfished; this means less food for cetaceans

Bycatch: 5 fisheries

gill net, trawl net, purse seine, pot fishing, long line

Category 1 Fishery

kills marine mammals frequently

Category 2 Fishery

kills marine mammals occasionally

Category 3 Fishery

rarely kills marine mammals

Which fisheries need permits and potentially observers on board?

Category 1 and 2 Fisheries

Hunting

many mysticetes and large whales have been severely hunted

International Convention for the Regulation of Whaling (1946)

includes all the whaling nations and formed International Whaling Commission (89 member states)

How did culture help whaling issues?

The publication of humpback whale songs and many ethical concerns pushed the public to have a different opinion on whaling

International Court of Justice: 2014

the court concluded that the special permits granted by Japan for the killing, taking, and treating of whales in connection with JARPA II were not “for purposes of scientific research”

Are dolphins hunted?

yes, dolphins are hunted for bait (estimated 20,000 dolphins are taken this way) and they are hunted for medicinal myths

Where are cetaceans hunted for food/culture? (“dry fisheries”)

Farose Islands, Soloman Islands, and Tajii

Pollution

can come from contaminants, runoff, fertilizers, plastics, etc.

Biomagnification

contaminants that don’t easily degrade stick to small particles and phytoplankton, which moves its way up the food chain causing apex predators to be highly contaminated with pollutants

How are dead zones created?

pesticide runoff results in harmful algal blooms which eat up all the oxygen and create dead zones

Climate Change

north and south poles are highly favored areas for feeding due to upwelling, but productivity is getting smaller and smaller due to increasing temps which causes a shift North

What was the major cause for decline in Southern Resident Killer Whales?

removal from habitat for entertainment purposes

Countries that have banned cetacean captivity

Australia, UK, Costa Rica, India, Switzerland, Canada, Bolivia, Chile, Nicaragua, Norway, Brazil

What impacts did the Blackfish film have?

California banned reproduction of killer whales and the New England Aquarium chose to phase out captive dolphins

Which countries show growth in aquariums and live captures?

Asia and Middle East

Indirect Disturbances

not actively looking for dolphins, just happen upon them

Direct Disturbances

specifically looking for dolphins

What do dolphins do when boats are near?

Typically dive longer, swim faster, and change direction more which uses more energy

Gray Whales case study

in an area where females go to calve, there is a saltworks facility which produced a lot of noise; the whales stopped showing up there and only came back when the saltworks facility left

San Juan case study

there is a fish farm and killer whales would break into the fish farm to eat the fish, then the researchers put in noise makers to push the whales away, they were never seen near there again

Bahamas Case Study

there were an extreme amount of strandings due to sonar noise in the area

pingers

on nets that are set, only works/makes noise for a short amount of time

Mysticetes are mostly solitary but…

they will group for mating or for high productivity areas

Odontocetes group…

together

fission fusion

not set groups, like humans where we switch who we are with throughout the day

life long groups

shown by killer whales and sperm whales

Matrilines

near 100% related, everyone is related to one female

pods

>50% related, multiple matrilines come together

units and groups

sperm whales; units are nearly 100% matrilines, groups are more temporary and not as closely related

how are groups defined?

based on proximity (3 meter chain rule) but most researchers a method based on interactions

how are groups varied?

this depends on the risk/predation in an area or the feeding opportunities in a certain area

why do cetaceans form mixed species groups?

larger groups = more protection from predators and more opportunities to find food, however the different species hardly actually interact with each other

example of mixed species group

bottlenose and cetalia (opportunistic grouping)

examples of hybrids

pilot whale and common dolphin reproduced in captivity

bottlenose and cetalia / narwhal and beluga → both have evidence in the wild

Mysticetes feeding

gulp feeding, skim feeding, bottom feeding

bubble net feeding

used by humpbacks; they work together to feed, one produces bubbles in a ring, the bubbles rise to the surface which traps fish, then everyone rushes to surface to gulp feed

carousel feeding

everyone comes up at the same time, and take turns jumping at a ball of fish

mud plume feeding

solitary and in shallow water, create u-shape plume with fluke, fish swim towards plume, and dolphin lunges at plume last second to catch fish (only seen in Keys)

mud ring feeding

found in upper Keys; one dolphin creates a mud ring with fluke, the fish freak out and try to jump out of the ring, dolphins are waiting outside ring to catch fish in the air

strand feeding

dolphins work as a group, must be in a marsh land with soft mud on a slope, all at the same time they charge on shore and roll around to eat fish

sponge feeding

found in Shark Bay, Australia; bottlenose use sponges to protect rostrum while shuffling the bottom of the ocean

crater feeding

bottlenose will dig in sediment to find fish

kerplunking

hitting fish to stun

hydroplaning

swim fast to get into shallow water in order to eat

what do most odontocetes eat?

fish and squid

who only eats squid?

sperm whales

Resident Killer Whale vs Transient Killer Whale

resident killer whales focus on eating fish and transient killer whales focus on eating other marine mammals

who attacks dolphins specifically?

false killer whales

how do we know what they eat?

observations, stomach analysis, fecal analysis, and isotope analysis

where to most cetaceans migrate?

they typically move from Arctic waters to tropical

north atlantic right whale migration patterns

only the females migrate south to calve and the males stay in the northern parts

sperm whale migration patterns

the females stay in the tropics (potentially safer for calves) while males migrate to the females to mate

what is the one cetacean population that does not migrate?

there is a humpback population in the Indian Ocean that does not migrate

how to cetaceans navigate?

there is some evidence towards electromagnetic, however more evidence supports cues from the sun and stars and potentially cues from the shoreline

residents vs transients

traditionally residents stay in one location and transients move around

who has home ranges?

bottlenose dolphins

why do male dolphins range farther?

to avoid mating with relatives

freeze brand

form of photo ID for smaller cetaceans, literally brand the animal with a number

satellite tags

form of tracking, used a lot on stranded animals, very invasive

what do eastern north pacific gray whales do with calves?

they like to hug the coast when migrating, likely to avoid predation by killer whales

marguerite formation

circle like formation where they use tails to protect themselves, this is used by sperm whales

baby sitting

like the name, someone is always with a calf, likely due to predation by killer whales

what is a greeting ceremony?

excited behaviors by cetaceans when seeing a pod for the first time in a while

killer whales show this by forming two lines and staring at each other

how long do bottlenose bond?

3-4 years

how long do baleen whales bond?

~1 year

how long do killer whales bond?

bond is for life

how long do sperm whales bond?

female calves could stay for life while male calves move on to mate