Bycatch Flashcards

1
Q

Target catch

A

Species or species complex that is the target of fishery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Incidental catch

A

Non-target species that are retained (retention may be dependent on catch rate of target species)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Bycatch

A

Catch that is not retained (returned to the sea – dead or alive)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Bycatch may be….

A

Dead
Living at the time of release (Survival depends on conditions and environmental factors)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Non-regulator discard driving factors

A

Non-target species of limited value
Target species that are damaged, diseased or too small for the market (e.g., cannery)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

regulator discard driving factors

A

Protected species
Size limit (minimum size, slot limit)
Closed season or area
Protected sex
Quota already filled
Retention limit (exceeds allowable fraction of target catch or bag limit)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Global discards cut by ~50%+ 1980s–2010s
WHy?

A

Greater utilization of bycatch species (aquaculture feed)

More selective fishing methods

Management measures prohibiting or limiting bycatch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Country-level mandates

A

EU landing obligation (no discards since 2019, though some exemptions)

Iceland, Norway, Namibia prohibit discarding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is another possibility associated with the decline in bycatch?

A

Possible that bycatch populations have decreased relative abundance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are ways to manage bycatch?

A

Limit overall effort (also reduces target catch)
Time/area closures
Bycatch reduction equipment
Incentivize selective fishing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Time/area closures is related to

A

Relative abundance of target species and bycatch species are spatial/temporally variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does bycath reduction engineering require?

A

difference in biology (size, movement, behavior, etc.) between target and bycatch species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

U.S. Gulf of Mexico Shrimp

A

“Gulf shrimp” includes white, brown, and pink shrimp

Fishery operates using bottom trawls (twin otter trawls most common)

Economically important fishery → $300M+/yr

Abundance environmentally driven

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Bycatch in shrimp fishery

A

During 1990s, high bycatch rates became an increasing concern (bycatch made up ~84% of total catch by weight)

~90% of age 0 red snapper mortality due to shrimp bycatch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Turtle Excluder Device (TED)

A

Early designs (‘88 – ‘03)
97% turtle exclusion
4% fish bycatch reduction
0-6% shrimp reduction

2021 NMFS requires TEDs be used in skimmer trawls >40ft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Shrimp finfish bycatch

A

Much greater than target catch, large number of juveniles (some adult stocks overfished)

Bycatch reduction devices required since 1998 (several approved designs)

2005 red snapper assessment recommended a 74% reduction in shrimp trawl bycatch mortality → primary factor affecting stock recovery

17
Q

Alaska pollock

A

$300M+, 3B+ lb in annual landings (largest in US by volume)

Caught using mid-water trawls targeting schools

18
Q

Alaska pollock bycatch

A

Relatively low bycatch rate (~1% by weight); still substantial given magnitude of the fishery

Bycatch includes: halibut, herring, salmon

19
Q

Salmon bycatch with Alaska pollock

A

Trawl fisheries in Bering Sea and Gulf of Alaska associated with salmon bycatch (Chinook, chum)

Salmon are considered prohibited species in Alaskan groundfish fisheries (cannot be retained for sale)

Bycatch highly variable year-to-year

20
Q

Slamon bycatch managed how?

A

Prior to 2011, salmon bycatch managed via time-area closures

Fishery management plan amendments (2011, 2012, 2016) aimed at reducing salmon bycatch by incentivizing selective fishing behavior

21
Q

Incentive plan agreements (IPAs)

A

plans developed by each sector to penalize bycatch and reward clean fishing at the vessel level

22
Q

IPAs introduced into Salmon bycatch

A

Vessel bycatch allocations (similar to IFQ), including rewards/penalties based on bycatch avoidance
Insurance pools
Hotspot maps / increased fleet communication
Use of salmon excluding devices

23
Q

How are the IPAs working?

A

Chinook salmon bycatch down ~50% compared to 1991-2010; chum salmon bycatch increasing

24
Q

Eastern Pacific Tuna

A

Commercial fisheries since early 20th century targeting yellowfin, skipjack, and bigeye

Before 1960s, fishery was primarily pole-and-line vessels out of California using live bait and fishing coastal waters (clean fishery)

Purse seining began in 1960s/1970s

25
Q

Dolphin bycatch with Tuna fishery

A

Dolphins (spotted, spinner, & common) often associated with larger yellowfin tuna

Dolphins chased down with speed boats, purse seine set around dolphins and tuna

High mortality of dolphin caught in nets 1960s/1970s (difficult to estimate precisely)

26
Q

Dolphin bycatch public concern

A

beginning in late 1960s

Marine Mammal Protection Act of 1972 led to a mandatory observer program for US vessels
~33% of trips by 1977

27
Q

“Dolphin Safe” Tuna

A

US canners refuse to purchase tuna caught using dolphin sets, leading to the creation of the “Dolphin Safe” label via the 1990 Dolphin Protection Consumer Information Act (16 USC 1385)

28
Q

Tradeoffs in tuna bycatch

A

Shift from dolphin sets to log/FAD sets reduces dolphin bycatch but increased bycatch of other species