EE32

Question 1

what is logistic growth of population management?

Answer 1

population growth/unit time

shows population growth rate equivalent to how much you can harvest/time without decreasing population

Question 2

what are the assumptions of the logistic model of population management?

Answer 2

growth at N=0 =0
growth at N=K=0
-

Question 3

When is logistic growth of a population as a max?

Answer 3

when population is at half the carrying capacity

need not correspond to reality

Question 4

what is msy?S

Answer 4

Maximum sustainable yield
max sustainable yield possible
peak of net recruitment curve
as curve is how much you can take without lowering the population
highest point is max that you can take theoretically

Question 5

what is a net recruitment curve?

Answer 5

shows how many individuals are added/unit time at each level of a population
how much you can harvest at each level of a population without decreasing population further.

Question 6

how can you infer what a population will do?

Answer 6

if you plot the harvesting strategy and recruitment curve together
if the harvesting strategy is lower than the recruitment curve then the population grows.
if its higher then it shrinks.
equal stays the same

Question 7

what are the dangers with fixed quota harvesting strategy

Answer 7

dangers of extinction
- if know the msy exactly the population is in an unstable equilibrium
eventually extinction due to random variation
overestimate is automatic extinction

Question 8

what is the harvesting strategy?

Answer 8

amount you take dependent on population level

Question 9

what happened in the peruvian anchovy fishery?

Answer 9

used to the biggest in world
mys estimated too high
stocks plunged
industry collapsed

Question 10

which method is somewhat safer than fixed quota msy?

Answer 10

fixed effort harvesting strategy
still extract msy but may still not be safe
dependent on recruitment curve

Question 11

what is the equation for fixed effort harvesting?

Answer 11

H=qEN
H=harvest
q=efficiency
e=effort
N=population/stock size

Question 12

when is a quota likely to be low?

Answer 12

when population low in a fixed effort system
can also occur if harvesting becomes more efficient at lower levels.
eg. fisherman know where schools are

Question 13

What are the breakpoints in models?

Answer 13

the tipping points

is sytem goes to new stable state hard to bring back to original

Question 14

what are the dangers of msy

Answer 14

ignores individual variation in a population
often predominantly on a certain individual
eg. male deer with antlers
bigger fish.