intro to marine conservation Flashcards
when did human impacts on marine life become apparent
- 1950s - started noticing depletion in fishes
- 1800s - Marine extinctions
4 important historical things that indicate marine resource usage
Before the colonial era
American colonists
Pacific
Mechanized fishing dredging
what happened before the colonial era that indicated marine resource usage
- Stellar sea cows – fossil record showed reduction in range – matches colonization by natives
- Sea otter – fished down
- Sea mink
- Dugongs
- Manatees
- Neanderthals (before humans) used to exploit the ocean for food
what happened with American colonists that indicated marine resource usage
- Green + hawksbill sea turtles
- NE species – sea mink fishes
what happened in the pacific that indicated marine resource usage
Last of stellar sea cows
Otters
Dugongs
what happened with Mechanized fishing dredging that indicated marine resource usage
“Final whammy” for fishes + oysters
Aboriginal Peoples vs European Colonists impact on marine life
AP = Undetectable to local extinctions
EC (17 - 19th cen)= More extensive impacts + runoff
what are shifting baselines and who came up with it
Pauly 1995
- Look at things at beginning of career and use that as their baseline of what a healthy ocean looks like
- but they are already substantially reduced – have to look at further back records, not when you first saw it
Effects of removing species on rest of food webs
- Largest predetory species usually fished first - crashed
- Lower trophic fishes + inverts are fished
- reduces number of trophic levels in ecosystem
6 Major anthro impacts
Fisheries = number 1
Pollution
Alteration of ecosystems
Invasive species
Diseases
Climate change + ocean acidification
what are synergistic effects
total greater than sum of parts – each impact weakens the systems – more vulnerable to next impact
