ExtinctMammals
Extinct Marine Mammals
Past Extinctions
Causes
Effects
On Humans
• Overexploitation seems to be the main issue – loss of fish from overfishing and poor practices can destroy ways of life, jobs, industries, etc.
• Marine mammals are often caught as bycatch
• Unregulated harvest
• new and innovative solutions to this problem are required to take account of the socioeconomic conditions experienced by fishermen” (Merritt)
• Issue of regulation versus deregulation – looking at pros and cons of regulation seeing as it costs a lot, but is significant in saving a species
o Regulation = politically unpopular (Merritt)
• Poverty and the collapse of other industries can lead to abrupt changes in local fishing conditions – may start to prey on marine mammals once their value as food and bait is noticed
o Unregulated and unsustainable (Merritt)
o Peruvian dolphins; anchovy fisheries collapsed so people started hunting dolphins; led to depletion in population (Merritt)
On Ecosystems
• World’s fisheries are not only impacting marine mammals, but the trophic structure as well – by capturing huge amounts of fish they are causing changes in energy pathways and species numbers (Merritt)
o Affect marine mammals adversely
• Loss of biodiversity/ decline in mammals can cause population imbalances in other species (Munday)
Connection to Coral Reefs
• Lots of extinctions/endangerment is caused by loss of habitats – coral reefs have declined 40 percent world wide (Zimmer)
o Partly a result of global warming (Zimmer)
• Loss of coral due to bleaching/global warming have changed the structure of coral reef ecosystems and communities – lead to changes in the fish communities, which lead to more changes through the trophic levels (Munday)
• Direct relationship between abundance of coral and abundance of coral dwelling fish (Munday)
Prevention
• Oceans, unlike terrestrial ecosystems, are still mostly intact – could easily bounce back if they’re taken proper care of (Zimmer)
o Somewhat uncertain about this though – it’s much harder to track the health of ocean mammals than it is of terrestrial ones (Zimmer)
• Not irreversible yet (Zimmer)
• Regulations for overharvesting of fish – mammals such as dolphins often become entangled in nets and will be benefited by such regulation (Zimmer)
• Still time for humans to stop the damage with effect programs that “limit the exploitation of the oceans” (Zimmer).
• Slowing extinction = cutting back on carbon emissions (Zimmer)