Deepsea Fisheries & Shark Fisheries

Question 1

Deepsea Fisheries and Shark Fisheries: Why Together?

Answer 1

Similar life history traits

Long-lived

Slow growing

Late age of maturity

Low fecundity

Typically, “boom and bust” fisheries (due to mismanagement, not the environment!)

More like fishery “mining” or “clear-cutting” – exploit and move on

Question 2

Fishery characteristics

Answer 2

c. 70 species or species groups known to be caught >400 m depth
c. 40 species or species groups caught between 200-400 m depth
Small in terms of overall contribution to global capture fisheries (0.5%), but under-reported up to 42%

Question 3

What is a trend that has become evident with some research studies?

Answer 3

• Over time, more species are being encountered, so the range of exploitation is increasing over time.

Question 4

Orange Roughly main Family

Answer 4

Beryciformes

Question 5

What are the three families within the Beryciformes family?

Answer 5

Trachichthyoidei
Berycoidei
Holocentroidei

Question 6

Main fish within Trachichthyoidei family

Answer 6

Fangtooths, flashlight fishes, pinecone fishes

Question 7

Main fish within Berycoidei family

Answer 7

Alfonsinos

Question 8

Main fish within Holocentroidei family

Answer 8

Squirrelfishes, roughies

Question 9

Orange Roughy Biology

Answer 9

• Generalist body form
  -Feeds on fish, squid, and zooplankton
  -Size: 72cm, 7 kg
• Slow growing (42 cm at maturity in NE Atlantic)
• Age at first maturity (23-40 yrs)
• Maximum age 100+ years

Question 10

Organe Roughly - Spawn Characteristics

Answer 10

Winter spawning aggregations around seamounts
Fecundity: 20,000 – 30,000 eggs/kg (relatively low)
Single batch spawners – synchronous
Eggs (~2 mm) rise up and develop in ~10 days
Pelagic larvae

Question 11

What characteristics lead to the depletion of the orange roughly species?

Answer 11

Spawning characteristics plus exploitation

Question 12

Orange Roughy Fishery

Answer 12

• High value, white meat product
• Started in New Zealand in the 70’s.
• Fish 500-1500 m over slope, sea mounts
• Smaller Trawl nets than cod fisheries
• Target feeding and spawning aggregations
• NZ started to export to US in the late 80’s. Causing a crash in fishery.

Question 13

Why was this a boom-and-bust fishery?

Answer 13

Little fishing efforts with high yields since they could target feeding and spawning aggregations.

Question 14

Biology of Sharks (and rays)

Answer 14

• > 1000 species of sharks & rays
• slow growing
• many do not reach maturity until 15+ years of age
• Low fecundities
• Long lived

Question 15

Sharks and Rays Fecundity Characteristics

Answer 15

One or two year reproductive cycles
Few number of pups per cycle

Question 16

U.S. Shark Fisheries

Answer 16

Minor shark fishery in U.S. prior to 1970s (California soupfin shark for vitamin A)

Perceived as an underutilized resource, fishery promoted

Fishery for meat, but fins extremely valuable

Rapid buildup, peaking in U.S. Atlantic in 1989

Quickly overfished

Question 17

Shark Finning

Answer 17

Banned in U.S.
U.S. Atlantic requires landing
with fins attached
Banned in Atlantic (ICCAT)
Originally 5% fin/carcass ratio
Now land with fins attached since it’s hard to tell the fish species without the rest of the body.

Question 18

What were the issues with the shark fisheries stocks/management?

Answer 18

• Landings records are not good
  Problems with species identification
  Problems with recording bycatch species

Question 19

What is the percentage of reduced biomass?

Answer 19

Oceanic shark biomass declined by 71% since 1970

Question 20

Why are the rebuilding times so long?

Answer 20

Due to life history characteristics. However, recent studies show that they are rebuilding.