Fisheries Management

Question 1

Why do we need management?

Answer 1

Exploitation (ex. marine fisheries)

Conservation of endangered species (ex. Sea Lamprey in Ireland)

Eradication/control of invasive/pest species (ex. Sea Lamprey in Great Lakes US)

Question 2

What percent of global fish stocks are over-exploited, collapsed or used at maximum capacity according to the UN?

Answer 2

80%

Question 3

Players affecting the resource

Answer 3

Fishing fleets, abundance, maximizing catch, profit

Question 4

Priorities

Answer 4

Maximize benefits (biological, economical, social)

Avoid undesirable outcomes (fishery collapse, economic inefficiency, habitat loss, endangered species, unemployment)

Question 5

Steps in the management process

Answer 5

Asses status quo (identify stocks, assess parameter, predict viability)

Determine objectives

Develop strategies

Take management action

Review success in meeting objectives

Question 6

Management action

Answer 6

tactics to achieve strategy and meet objectives by modifying behavior of fishers

often divided into: catch controls, effort controls, technical measures

Question 7

Management strategies

Answer 7

specific statement of approach to meet objectives

depends on stock assessment data, fisheries models, biological understanding, and other socio-economic, environmental, and political factors

ex. Icelandic cod - catch 25% of stock aged 4+ each year

Question 8

Species of concern

Answer 8

river herring - 90% decrease in NC in the last decade (overfishing, habitat destruction, dams keep them away from breeding grounds)

Question 9

Bottom trawling

Answer 9

weighted fishing net that is dragged along the seafloor to catch bottom-dwelling fish. lots of by-catch (more than pelagic) and damages seafloor habitat (species: cod, flounder)

Question 10

Pelagic trawling

Answer 10

large cone-shaped net hauled through water at a higher depth than bottom trawling for school of fish (mackerel, herring, sprats)

Question 11

Dredging

Answer 11

large, metal frame baskets dragged across the seafloor to collect shellfish. damages seafloor habitat, harms bottom swelling species, lots of bycatch, kicks up sediment

Question 12

Purse seining

Answer 12

boat drags a large circular net through the water. less by-catch than trawling (mackerel, bluefin tuna, herring)

Question 13

Long lining

Answer 13

floating central fishing line (very long) strung with smaller lines with baited hooks at evenly spaced intervals. can hook sea turtles, sharks, and seabirds attracted to bait. (species: swordfish, yellowfin tuna)

Question 14

Drift nets

Answer 14

Long nets with thin mesh, outlawed in many places, very bad bycatch (squid, swordfish)

Question 15

Traps/pots

Answer 15

baited wire traps or cages typically attached to buoys. not much seafloor impact. generally lower unintended catch rate
(lobster, crab)

Question 16

Deep-sea longlining

Answer 16

hooks on seafloor (Chilean sea bass, halibut)

Question 17

Line fishing

Answer 17

fishing poles with bait fish. high-quality fish bc not mangled and caught alive (yellowfin and skipjack tuna)

Question 18

Fishery-dependent data

Answer 18

collected directly from commercial and noncommercial fisheries

can be used to develop stock assessment models

pros: easier to acquire, cheaper
cons: possible bias, demands collaboration, gear selectivity

Question 19

Fishery-independent data

Answer 19

collected independently from commercial or noncommercial fishery data. run by federal/state agencies or research bodies.

generally collected using sea surveys following an experimental design. studies stock abundance, life history, and environmental factors contributing

pros: no bias/more truth
cons: expensive

data collection (fish tagging, biological sampling, cooperative research w/ fishers, underwater vehicles, stationary point count…)

Question 20

independent/non-commercial fishing

Answer 20

electrofishing (illegal w/o permit)
net fishing
longline
traps
rod and line

Question 21

data collection techniques

Answer 21

fish counter using conductivity

hydroacoustics

snorkeling/diving (used for redd/nest count)

environmental DNA (sample water)

quantitative PCR

metabarcoding

Question 22

non-lethal sampling

Answer 22

scale collection, fin clips, parasites, blood samples, stomach flushing, recording injuries

Question 23

lethal sampling

Answer 23

can kill by anesthetic, ice, blunt trauma

gonads (sex, stage of maturity), disease, internal parasites, muscle tissue for genetics, otoliths (ear stones), vertebrae

Question 24

what parts of the fish can be used for aging/migration data (using rings)

Answer 24

scales

otoliths (biomineralized ear stones that contribute to both hearing and vestibular function in fish

vertebrae

Question 25

tagging methods

Answer 25

floy tags, carlin, coded wire in the nose, visible implant, PIT (injectable), radio, satellite acoustic tags (good for tracking and large sea animals), natural tags (genes, stable isotopes), adipose fin (removed in hatchery salmon, intact in wild salmon), panject dyes injected into fish