Conservation, Fisheries, and Aquaculture Flashcards
1
Q
Active Fishing
A
- feature methods designed to chase and capture target species
2
Q
Active fishing examples
A
- encircling seine nets
- trawls and trawl netting
- dredges
- harpoons, spears, and explosives
3
Q
Pros of active fishing
A
- tailored to effectively catch a specific species
4
Q
Cons of active fishing
A
- harmful environmental impacts
- accidental capture of non-target species
5
Q
Passive fishing
A
- feature methods and gear that not actively controlled or monitored by humans while organisms are being captured
6
Q
Passive fishing examples
A
- gill nets (seafloor or floating traps)
- baited pots (common for crustaceans)
- long lines
7
Q
Pros of passive fishing
A
- less labor intensive
- traps work all the time during deployment
8
Q
Cons of passive fishing
A
- ghost fishing: trapping fish in abandoned gear, leaving them to die needlessly
- caught fish can be preyed upon
- higher chance of escape
9
Q
causes of overfishing
A
- only targeting large, mature individuals
- focusing mainly on top predators w/ low biomass
10
Q
consequences of overfishing
A
- top-down trophic cascades
- loss of reproductive adults leads to low recruitment yields and fishery can collapse if not enough young are generated to sustain the population
- fishing at lower trophic levels deprives the ecosystems of base food sources (bottom-up effects)
- stocks with long generation time, small egg clutches, and few spawning events are the most vulnerable
11
Q
How can we better manage fisheries?
A
- minimize effects of climate change
- temporary closures for regeneration
- use catch share or individual transfer quota systems
- practice ecosystem-based management
- followed guidelines of Marine Protected Areas (MPA)
12
Q
Latitudinal gradient of biodiversity
A
- species diversity tends to increase w/ decreasing latitude
[more diverse at the equator] - holds true on shelf, in benthos, and in open oceans with some exceptions (of course)
13
Q
Latitudinal Gradient (Temperature)
A
- one explanation for the gradient may be temperature which increases as you approach the equator (positive correlation)
- after the last global cooling event and glacial retreat, more species evolved to survive in warmer waters
14
Q
Latitudinal Gradient (Seafloor spreading)
A
- another explanation of the gradient may be the tectonic activity of seafloor spreading and continental drift
- this produces extensive north-south coastlines which distributes shallow biota along a latitudinal gradient
15
Q
Ecosystem-based management
A
- an approach to conserving ecosystems that includes all the components of ecosystem function
- allows us to better conserve biodiversity by helping us allocate resources more effectively to areas of the ecosystem that need it most
16
Q
Examples of Ecosystem-based management
A
- habitat protection: minimize human impacts on natural ecosystems
- sociological approach: gov’t and organization involvement, make sure the public is informed about how their actions affect the environment and its resources
- economic considerations: attach monetary values to all parts of an ecosystem to determine which aspects are the most critical to financially support
17
Q
passive cultivation system
A
- organisms grow in cages or on racks in the water along a coast and take up nutrients directly from the water
18
Q
species from passive cultivation systems
A
- macroalgae
- mussels
19
Q
semi-enclosed cultivation systems
A
- ponds along coastlines with seawater intakes and waste outtakes which are connected to the ocean
20
Q
species from semi-enclosed cultivation systems
A
- Tilapia
- shrimp
- prawns
21
Q
suspended net cultivation systems
A
- nets floating in the open ocean which allows for free exchange with the environment
- generally considered more high-risk and can attract predators to the area
22
Q
species from suspended net cultivation systems
A
- mainly salmon
23
Q
Monoculture
A
- most widely used system
- used to cultivate a single species for sale and use
24
Q
Pros of Monoculture
A
- limited equipment and food inputs
- highly efficient production
25
Cons of Monoculture
- high density of organisms leads to higher stress levels in individuals and a greater risk of disease and parasitic infections
26
Polyculture
- cultivation of multiple (companion) species together
| - usually associated with subsistence practices
27
Pros of Polyculture
- less environmental manipulation
| - less stress on the organisms
28
Cons of Polyculture
- more expensive on start up
- generally less efficient from a production standpoint
- multiple species require multiple specific care regimes
