topic 17 -Conservation: Fisheries

Question 1

Conservation practices are based on a

Answer 1

thorough understanding of the principles of ecology

Question 2

conservation must integrate

Answer 2

ecology with social, political and economic systems

focus: harvesting species

Question 3

Atlantic Cod

length and weight ?
life span?
maturity?
how many eggs?

Answer 3

2 meters and 200+ pounds
25 years lifespan
2-4 years
females can lay millions of eggs

Question 4

Canadian cod fisheries are centered around

Answer 4

the grand banks

Question 5

Cod Populations

originally discovered by?

Answer 5

discovered by John Cabot 500 years ago

so abundant you could walk on their backs, thought to be infinite

Question 6

Declines in cod across their range including

Answer 6

Baltic Sea and especially coast of Newfoundland and labrador

Question 7

cod landings 
1950s
1977
1991
1992

Answer 7

50s lots of cod, factory freezer trawlers
77 200 mile limit EEZ
91 cold year
92 fishing moratorium

Question 8

in the 1950s, technology allowed fishermen to fish by

Answer 8

trawling a large area to a deep depth for longer times

Question 9

in the 1960s, technology allowed fishermen to be equipped with

Answer 9

powerful trawlers equipped with radar, electronic navigation systems and sonar which allowed crews to catch fish with unparalleled success

Question 10

since 1977 (200 mile limit Exclusive Economic Zone)

Answer 10

excluded foreign nations from fishing in Canadian waters

Canadian Government set the annual harvest rate based on information from scientists

Question 11

After WW2 scientists overestimated N-set annual harvest rates too high, the estimates of N were

Answer 11

based on commercial catch rates (assumed high catch=high N)

Question 12

Aggregated (dispersion) during spawning allowed

Answer 12

high catches while population was declining fast

Question 13

underestimated mortality from fishery

Answer 13

catches misreported

large discarding in by-catch when harvesting other species

Question 14

in 1980s annual harvest rates were higher than scientists recommended due to

Answer 14

fishers lobbied hard for higher harvest rates, attitude was that cod was a super-abundant resource

Government maintained annual harvest rates higher than recommended to avoid political suicide

Question 15

1992 population had declined to

Answer 15

99% of its original level

Question 16

1995 saw a slight increase in population size therefore

Answer 16

the government reopened a small inshore fishery despite strong opposition from scientists

Question 17

2003 fishery closed again population declined to

Answer 17

99.9% of its original level, recommended to be listed as an Endangered species under Canadas Species At Risk Act (SARA)

Question 18

1992 there was a fishing….

which lead to how many unemployed

jobs lost

Answer 18

moratorium, fishery closed to allow population to recover

19000 fishers and plant workers became unemployed
20000 other jobs lost (100s of small communities cod was only employer)

Question 19

what did fishers do when work was lost

Answer 19

TAGS program -social assistance
retraining programs
Emigration of people out of NL to find work
Fishers shifted to harvest other species

Question 20

By-catch

Answer 20

unused catch discarded at sea -target and non target species

ex shrimp trawl species 3:1 to 20:1 by-catch: landed

misreported and illegal catch and by catch, hard to estimate population declines

cod killed by nets or die when brought to surface (returned to ocean dead)

Question 21

why are food webs complex?

Answer 21

need to more about how species interact to understand how adding/removing a species will influence community structure and to conserve marine biodiversity

Question 22

Population resilience

what does it combine

Answer 22

rate at which population returns to equilibrium size (k) after a population crash

combines the age structure, spatial structure and life history characteristics of a population

Question 23

r-selected resilience

Answer 23

invest heavily into reproduction (high r) shorter potential time to return to K again if population is reduced (quick recovery, high resilience)

Question 24

k-selected resilience (cod)

Answer 24

invest heavily into growth/survival (low r) longer potential time to return to K again if the population is reduced (slow recovery, low resilience)

other problems with small population: inbreeding, genetic drift

Question 25

2015 Fishery Improvement Project, 25 years after the moratorium…

Answer 25

and cod populations still exist in the critical zone (300,000 tonnes)

Question 26

Rose and Rowe 2016

Answer 26

Northern Cod comeback
10 000 to 200 000 tonnes in a decade
growth rates approaching 34% per annum
recommended to allow population to grow to 900 000 tonnes to bring back sustainable historical yields (should take another decade)

Question 27

small scale commercial fisheries being opened by Newfoundland and Labrador Groundfish Industry Development Council (NL-GIDC) has lead to

Answer 27

growth rates decreased to single digits

plans to expand fishing license and length of season