LEC 20 - MARINE RESOURCES Flashcards
what is standing stock + maximum sustainable yield
specific amount of organisms in a system at a given time; amount that can be removed from the standing stock while remaining sustainable
what are the factors that determine standing stock? (4)
- immigration into the system
- survival of youth into reprod age
- nutrient avail
- location
when one year has a good stock size, what is the likely trend for the following year?
recruitment will decrease since resources will get used up
what is the allee effect (depensation)? how does this matter for standing stocks?
while it holds true that in high density populations indiv compete for resources etc, exceedingly low density pop also struggle to sustain the population (ex. pack animals)
in a standing stock, having too few adults can lead to insufficient recruitment to sustain the population, leading to population decline
what is trawl fishing + why is it bad? (3)
trawl fishing is the casting of nets that follow a boat - can be cast from the middle of the water column to the ocean floor
this is bad bc:
- it hooks onto corals etc
- stirs up sediments which gets excess nutrients into the water column –> plankton go brazy
- flattens the sea floor, reducing habitat avail
what is drift net fishing + why is it bad?
drift net fishing is the casting of large (>1km) nets;
bad bc of excessive amount of bycatch (unintentionally caught animals such as turtles
what is a take reduction team? what is the NOAA?
teams whose purpose is to find out how contend conservation with fishing
the NOAA is a team dedicated to protecting whales, especially through the capping of rope strengths such that fish can be caught, but whales can break through if caught (1700lb breaking strength)
how are jellyfish feeling about overfishing?
actually pretty good lol fish pops going down means less competition for plankton
what is aquaculture? what are some trends we are seeing w # of aquaculture farms vs companies involved?
aquaculture is farming but for fish
we are seeing more farms but less companies (trending towards monopolization)
what are some challenges faced w aquaculture? (4)
- feeding
- waste production, leading to intense eutrophication
- antibiotics and other chemicals affecting non-aquaculture animals
- sea lice infestations going brazy when given the opportunity
what is the problem with shrimp aquaculture?
they aren’t really cultured, they’re kinda just grown in an area until the fuck it to the ground
what is the purpose of aquaculturing algae? (3)
food, nutritional supplements, food stabilizer
