Dolpin (8) Flashcards
How do dolphins swallow their food?
Dolphins swallow their fishy food head first - this is so that bones don’t get stuck in their thoats.
What major impact do fisheries have on UK cetaceans?
Fisheries can significantly affect the status and distribution of various UK cetaceans.
Which fish stocks have shown marked changes in population due to fishing pressure (6 Points maximum)?
- Sprats
- Sand eels
- Herring
- Whiting
- Mackerel
- Haddock
What is the consequence of over-exploitation of fish stocks on marine mammals?
Over-exploitation leads to dramatic declines in fish stocks, imposing major pressures on marine mammals that depend on them for food.
What was the status of North Sea herring stocks by 1977?
North Sea herring stocks collapsed to about 5% of post-war levels by 1977.
What happened to sand-eel stocks in Shetland during the 1980s?
Sand-eel stocks in Shetland declined dramatically, leading to the closure of the local industrial fishery.
What consequences did the decline in sand-eel stocks in Shetland have on local seabirds?
Local seabirds suffered repeated and widespread breeding failure, resulting in thousands of chicks starving to death.
What led to the near extinction of most great whales in the world’s oceans?
Centuries of hunting
Which country was one of the leaders in causing the demise of great whales?
Britain
In which decade were there active whaling stations in Shetland and the Outer Hebrides?
1920s
How many British whales were killed collectively over a period of fifteen years in the 1920s?
Nearly 10,000 whales
Which whale species are mentioned as being very rare in UK waters?
- Northern right whale
- Humpback whale
- Blue whale
What signs of recovery have been observed after thirty years of protection in the North Atlantic?
Some signs of recovery for blue whales and humpbacks
What type of whaling resumed in the 1990s?
Scientific whaling
How many minke whales did Norway take in waters north of Shetland in the 1990s?
Around 800 minke whales
Which country has joined Norway in resuming whaling as a commercial activity during the 1990s?
Iceland
True or False: The whaling activity mentioned has completely ceased.
False
Other than your name, date, and email address, what else do you need to record before starting a land watch survey?
Longitude and latitude.
When doing a land watch survey, how often do you record environmental data?
Every 15 minutes
What five environmental conditions should you record when doing a land watch survey?
SSWVB
- Swell
- Sea state
- Wind direction
- Visibility
- Boat activity
When doing a land watch survey, what are the three mammals you’re most likely to see?
- Seals
- Bottlenose dolphins
- Harbour porpoises
What is logging?
When marine mammals rest at the the surface of the water (they look like logs).
Some long-finned pilot whales logging.
For how long do dolphins sleep each day?
Eight hours.
What does it mean when dolphins are milling (3 Points)?
- Group frequently changes travel direction (no consistent travel direction).
- Individuals may surface facing different directions.
- Dolphins have slow movements with variable, but frequent, dive intervals and often remain floating at the surface for a short amount of time between dives.
How exactly do dolphins socialise (3 Points)?
- Through direct physical contact.
- This can include… dolphins rolling over, biting, pushing, and petting each other.
- Splashes and disturbances at the surface are also frequently seen.
How can you tell if dolphins are feeding (5 Points)?
- Feeding is usually associated with deep diving (fluke-up dives)
- They’ll be swimming around very quickly
- They’ll frequently change direction and inconsistent inter-breath intervals.
- Group may be in a circular formation, spread over a wide area
- Individuals surface facing different directions.
What is sea state measured in (Hint: Beaufort)?
- It’s measured by using the Beaufort Scale (With numbers from 1 to 12).
- 0 is the lowest score - it means that the sea is calm and looks like a mirror.
- 12 is the highest - these are hurricane conditions.
How exactly do you determine the current Beaufort Scale?
By measuring the winds and the heights of waves.
How can you tell if the Beaufort Scale is currently 4?
- There are 13-18mph winds
- Waves are 1-2m tall
How can you tell if the Beaufort Scale is currently 8?
- There are 39-46mph winds
- Waves are 5.5-7.5m tall
