Land Use #1 Fishing and aquatic food production Flashcards
What are the ocean layers
Epipelagic
Mesopelagic
Bathypelagic
Abyssopelagic
Hadal
ocean layers
Epipelagic
- Surface - 200 m
- Most sunlight = most productive
- sunlight zone andwde range of temps
ocean layers
Mesopelagic
200-1000 meters
transition layer where its warm water to cold water
ocean layers
Bathypelagic
1,000 - 4,000 m
no sunlight high adapable speices live here
ocean layers
Abyssopelagic
- the Abyess
- pitch black (nearly freezing temps) with very few creatures living here
- 4000- 6000 meters
Ocean layers
Hadal
- 6,000+ m (deepest)
- highest pressure and freezing temp
Continental shelf
What is the Continental shelf
- Extension of continents under the seas and oceans
- Creates shallow waters
- holds 50% of waters nutrients
Continental shelf
Continental Shelf significance
Theres a lot more life at this level with things such as crabs and fish living there
Ocean life
Benthic
live on or in sea beds (floor or shelf)
ex crabs and star fish
Ocean life
Pelogic
live surrounded by water (not on land)
ex sharks and Tuna
What does UNCLOS stand for
United Nations Convention on the Laws of the Seas
What did the UNCLOS do
-Established legal ownership to a coastal nation extending 200 miles from shore (Exclusive Economic Zone)
Types of fishing
Purse-seine
encloses fish in a large bowl shaped net
captures surface level stuff (tuna and herring)
Types of fishing
Long-lining
Putting out lines up to 60 miles long w/ thousands of bated hooks
captures sharks and cod and tuna mostly
Types of fishing
Drift (gill) Net
Wall-like nets that hang up to 50 feet deep & rip the gills off fish as they swim through
Good for economy bad for ocean life
Trap & kill large quantities of unwanted fish, marine mammals, seabirds, & sea
Types of fishing
Trap Fishing
Smaller traps are lowered attached by rope to the boat or buoys
Captures Crabs and Losters
Types of fishing
Bottom Trawling
Huge weighted nets drag across the ocean floor
Types of fishing
Cons about Bottom Trawling
Catch lots of unintended species
Stir up sediments (increase turbidity)
Can destroy structures like coral reefs
Decrease biodiversity by killing non-target species
Types of fishing
Pros about Aquaculture
- takes up very little ocean space
- reduces the likelyhood of fishiers industry collaping (by 90%)
- doesn’t take land space
- enhance production ( more fish in less time)
Types of fishing
Aquaculture
Raising fish or other aquatic species in cages/enclosures underwater
Best for ecosytem worst for economy
Types of fishing
Aquaculture drawbacks
- High concentration of waste or water pollution (e. coli & eutrophication risks)
- High density increases disease risk, which can be transmitted to wild populations as well
- May introduce non-native species or GMOs to local ecosystem if captive fish escape
- Fish are fed antibiotics which can contaminate water via their waste
Impacts of Overfishing
Fishery collapse: when overfishing causes 90% population decline in a fishery
* population may never recover
* Decreasing biodiversity
Fishing Down the Food Web & Trophic Cascade
Depletion of smaller fish pop. limits fishery recovery and decreases food supply of marine mammals & seabirds
Impacts of Overfishing
Bycatch: aquatic species caught unintentionally; often not kept due to non-target, over quota, illegal (endangered) or too small
dead/injury fish are thrown back into the ocean
Fishprint: area of ocean needed to sustain the fish consumption of an average person, nation, or world
Sustainable fishing
- Establish more Marine Protected Areas (MPAs)
- Staying at Maximum Sustainable Yield (MSY)
- Using efficient fishing methods that decrease the amount of potential bycatch
- More minimal catch fishing methods (spearfishing, hook & line, cast nets)
- Increasing government regulations/laws
- Consequences for overfishing
- Abstain or decrease fish/seafood in human diets
- Better overall fishery management
- Decrease in international water agreements
