Nigle's Niggles Flashcards
(12 cards)
Greenland
Where in Greenland?
What’s happening?
Why we care?
Where: Buffin’s bay
What: Buffin’s bay has a warm water current that has a disproportionately large effect on Arctic watter circulation.
Why we care: Melting of Greenland’s icecaps is predicted to be one of the highest contributors to rising sea levels- it’s a very important location to monitor climate change.
Sardine migration:
What drives this phenomenon?
What are the effects?
How are dusky sharks impacted?
What drives this phenomenon?
A seasonal reflux of cool watter drives the pacific sardines to migrate. They move through a narrow costal area and through the warm tropics.
- This concentrates billions of sardines
What are the effects?
Migration leads to large predator aggregation (odd species comes together to feed on sardines)
How are dusky sharks impacted?
Dusky sharks somehow know where the sardines are despite being very far away
they migrate to feed on them
Wildlife tagging
What is used?
How does it work?
What are the parts?
What is used?
Minipat tags-Wildlife computer satilite tags created for fully submerged aquatic animals.
What are its parts?
Dart: attaches to animal
Pin: allows for scheduled release
Floater: includes battery data archive and allows tag to float to surface when it disconnects
On the floater, there is a wet/dry sensor that connects to Argos satellites. It sends data to satellites when it’s dry.
Data on the mini pact tags
Time series data: depth, temp, light level (two times per day)
If data pact recovered, you can access 100% of data
Where were the two spots they were recovered in?
What did they capture?
How do we know?
Recovery 1:
Keel beach (Ireland)
-Measured an interaction between a Greenland shark and a Greenland halibut
-Greenland shark ate Greenland halibut then after months it inverted its stomach and the mini pack tag was recovered
We know because of the changes in depth and temperature
Recovery 2:
- Bordeaux France
- from a Greenland shark in 2021
- was used to study the anthropogenic effects of fishing on Greenland sharks
-Studied the post release mortality of bycatch of troll fishing of Greenland halibut
Why important:
- Sexual mature at 150
- Rarely pregnant
- up to 7 feet long
- can not recover from any anthropogenic stress
What happened?
- Shark died and sank to the bottom of the ocean or was eaten by another shark
- tag was released
Seagrass and Shark bay
What are the benefits of seagrass?
What’s the deal with Shark bay and ribbon weed?
What reduces it’s impact?
Seagrass creates habitats biodiversity food sources carbon sink/ o2 release
The ribbon weed in shark’s bay is a super organism (1 plant)
it’s 200km2 and, 4500 years old
-It has extremely high biodiversity:
^structural complexity (creating sediment stability)
^ water clarity
^resilience
Eutrophication, overfishing dredging
Trophic levels and sharks
How many species are there on earth?
Predicts 88 million eukaryotic species
Biodiversity and sea mounds
How many?
Effect on biodiversity?
Trophic pyramid?
Assention island and three mounds?
How far around sea mounds do we need to protect?
200000 in ocean only 5% explored
Sea mounds are hubs for pelagic predators they break the rules and form an inverted pelagic pyramid
Photopic zone: light up to 200 m in depth
The three close mounds to assention island are:
1.) Harris Stewart (deepest) not in pelagic zone -same productivity and diversity as ocean
2.) Graton and young
- same nnp but higher diversity
- high trophic biomass
Must protect at least 5.5 km around sea mound, ideally 40
Glapagos sharks vs Silky sharks
Galapagos sharks resident 100% of time
Silky sharks
50% residents
- They have DIEL Behaviour
- leave at night
Often partaking in central place foraging
- Sea mound= the home base, then they take extended foraging trips
- They probably go deeper into the mesopelagic area under photic zone, the area with the highest biomass
Positivity in scientific communication
- negativity is good for action, but only to a point
(don’t want people to give up) - Must address the bright spots in the Anthropocene (conservation success):
Ex. AIS (GPS tracking of illegal fishing)
Is there functional redundancy in sharks in the food web? Does that mean we can take a few out?
No!
