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Biology 4663: Advanced Elasmobranch Studies > Topic 7: Sharks of The Open Ocean Conservation and Research Part 2 > Flashcards

Topic 7: Sharks of The Open Ocean Conservation and Research Part 2 Flashcards

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1
Q

COSEWIC Risk ratings:

  • Porbeagle shark
  • White shark
  • Shortfin mako
  • Blue shark
  • Basking Shark
A
  • endangered (2004)
  • endangered (2006)
  • threatened (2006)
  • special concern (2006)
  • special concern (2009)
  • *based on biomass
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2
Q

What shark is the most widely distributed shark?

A

blue shark brah

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3
Q

Blue Shark:

- likes water temp - but can tolerate -.

A
  • 13-21
  • 7-27
    • very tolerant to temp ..more so than porbeagle and mako!
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4
Q

Blue Shark:

- Single _____ stock

A

North Atlantic

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5
Q

Blue Shark:

- Found in our waters during ___ and ___.

A

summer and early fall

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6
Q

Blue Shark:

- population is depleting due to?

A

bycatch

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7
Q

Blue Shark:

-does it have a yolk-sac placenta?

A

yes

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8
Q

Blue Shark:

- how many pups per litter?

A

26-50+…when stressed they abort…may be less when taken aboard!

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9
Q

Blue Shark:

- length at birth?

A
  • 40cm
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10
Q

Blue Shark:

- Reproductive cycle?

A

1-2 years

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11
Q

Blue Shark:

- when do females mature?

A
  • 5-6 years (190cm)
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12
Q

Blue Shark:

- when do males mature?

A
  • 4-6 years (180cm)
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13
Q

Blue Shark:

- they are among the fastest___

A

growing sharks!!

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14
Q

Blue Shark:

- max reported size?

A
  • 383cm

L> live for about 20 years possibly

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15
Q

Blue Shark:

- mating scares?

A
  • tend to heal up in about a year…heal pretty quick…females have thick skin
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16
Q

Blue Shark:

- mating is where? pupping?

A
  • mating: our area
  • pupping: near europe + africa
  • North-West Atlantic: fished just as heavily on either side…target of finning..
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17
Q

Blue Shark:

- they are easily caught making them?

A

the most intensely studied shark!

** mostly caught on commercial long line vessels…

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18
Q

Blue Shark:

- they have the highest tag?

A

return in the case of other shark species! spread quickly on the north atlantic.

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19
Q

Blue Shark:

- Diet?

A
  • small pelagic fish such as herring, sardines as well as squid, benthic fishes and invertebrates, small sharks, wounded marine mammals and carrion and sea birds
  • *pretty much will eat everything …..they do not actively hunt marine mammals but will attack injured ones
  • they are known to attack humans! *tend to be first to show up at marine -air disasters…will eat dead things etc…
  • *attacked by sea lions…
    • not really found in the bay of fundy
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20
Q

Blue Shark:

- have declined by over?

A

60%

** by catch and finning industry has destroyed populations

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21
Q

Blue Shark:

- Sustainable catch limit is known or unknown?

A

unknown

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22
Q

Blue Shark:

- is the population known or unknown?

A

unknown

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23
Q

Blue Shark:

- Canadian catch represents _# of Atlantic total

A

3% …maybe no scientific basis..no clue what other nations are catching…but suspect itt o be at 3…..Blue sharks are the least desirable of sharks! (body has a fast metabolism producing strong ammonium smell/taste therefore it wastes quickly! <–THIS IS WHY THEY ARE FINNED TOO)

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24
Q

Mako Shark:

- prefers water from _-_C

A

17-22 C

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25
Q

Mako Shark:

- found in our waters in the __ months

A

summer
** likes warmer water…late spring-summer months= in our water…large sharks are very rare of this species due to overfishing

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26
Q

Mako Shark:

- offshore wintering grounds in __ and ___ during fall and winter

A
  • Gulf

- Sargasso Sea

27
Q

Mako Shark:

- How are young fed?

A
  • eggs are released
28
Q

Mako Shark:

- litter size?

A
  • 4-21 pups (14-16 on average)
29
Q

Mako Shark:

- birth size?

A

70 cm

30
Q

Mako Shark:

- Reproductive cycle?

A
  • 2-3 years ?
    L> mating in summer and autumn
    **reproduce quicker than porbeagle
31
Q

Mako Shark:

- Females mature at what length?

A
  • 275cm ( 4-6 years)
32
Q

Mako Shark:

- males mature at what length?

A
  • 200cm ( 4-6 years)
33
Q

Mako Shark:

- longest size?

A
  • 394 cm
34
Q

Mako Shark:

- life span?

A
  • 29 years
35
Q

Mako Shark:

- Diet?

A
  • variety of fish ( tunas, swordfish, mackerels, squid, other sharks and marine mammals)
36
Q

Commercial Fisheries:

- Is finning legal in Canada?

A

no

37
Q

Commercial Fisheries:

- All ground fishers(flounders etc) must land sharks?

A
  • whole..fins must be attached for shark/by-catch
38
Q

Commercial Fisheries:

- Large pelagic can do what?

A
  • remove fins but must retain caracas within 5% ratio ( for storage purposes)
    L> have agreed to let all sharks go that are alive
    L> using corrodible circle hooks (degrades quicker in tropical waters)
39
Q

Commercial Fisheries:

-Porbeagle and shortfin mako are?

A

greatest commercial interest

40
Q

Commercial Fisheries:

- No ___ fishery on shortfin mako and porbeagle

A

directed

41
Q

Commercial Fisheries:

- Stocks are low but?

A

are rebuilding to enhance fishery as they have destroyed everything else
** cancelled all fishing licenses of sharks except dogfish sharks

42
Q

Commercial Fisheries:

-By-catch monitored with?

A

dockside monitoring and observers at sea

43
Q

Commercial Fisheries:
-By-catch monitored with dockside monitoring and observers at sea:
L> Is it always accurate?
L> Any idea of true mortality of discards
L>Industry can keep sharks as___ but have to?
L> NO idea of ?

A
  • no not always
  • no
    L> up to 35% of blue sharks die on hook or after release..
  • by-catch but have to record in fishing logs (if no observer is on board how will this happen?)
  • foreign catches in open ocean and direct fishing
44
Q

dockside monitoring and observers at sea

- Mortality is divided into what three categories?

A
  • Retained catch
  • dead at time of capture and not retained
    L> mostly blues because mako and porbeagle = $$$$
  • Post release mortality
45
Q

dockside monitoring and observers at sea
- Mortality is divided into what three categories
L> Post release mortality:
- Discard mortality exceeds?

A
  • landings
46
Q

dockside monitoring and observers at sea
- Mortality is divided into what three categories
L> Post release mortality:
- Estimated at _% for blue and over _% for porbeagle and mako (DFO dumbs this down)

A
  • 35%

- 50%

47
Q

dockside monitoring and observers at sea
- Mortality is divided into what three categories
L> Post release mortality:
- _ mt of porbeagle, _mt of mako and __mt of blue (>45,000 sharks put back will die)

A
  • 30
  • 10
  • 500
48
Q

dockside monitoring and observers at sea
- Mortality is divided into what three categories
L> Post release mortality:
- death has a lot to do with what?

A

how sharks are handled!

49
Q

Recreational Shark Fishing?

A
  • catch and release
  • not derbies
  • no restriction on number of licenses
  • not considered significantly to shark mortality
  • 2013 saw 283 sharks killed (mostly blues)
  • one shark per day per license
  • *after shark derby video this was released not enforced but all boaters were given it!
  • *cna catch any amount as long as released with rec fishing
    • they should have mandatory circle hooks to prevent bad internal damaging caused by j hooks (mako and thresher are endangered and should be retained
50
Q

Explain recreational shark fishing rules that were released after shark derby video?

A
  1. A shark license must be obtained to fish for sharks, for both general and derby fishing. There is no limit not he number of shark licenses issued each year.
  2. Except for DFO sanctioned derbies, there is mandatory catch and release requirements for all sharks caught in recreational fisheries in Canada.
  3. All recreational shark fishermen including derby participants MUST submit logs of sharks caught
  4. Gear is restricted to rod and reel. There are no restrictions on hook type and size (WTF)
  5. For shark derbies specifically:
    - no shark less than 8ft total length can be retained except short fin mako and thresher sharks which must be at least 6ft long (WTF ENDANGERED)
    - there are no species restrictions except for the SARA listed great white sharks
  6. Derby participants and recreational fishermen may develop a tagging program in collaboration with scientists
51
Q

Best Catch, Handle And Release Practice for Shark Fishing:

- Step 1: Be prepared?

A
  • knowing that your fishing day may include catching a shark, there are several tools that should be on the vessel
  • dehooking devices such as a lot cutter or plier
  • gloves for safe handling of sharks
  • tagging gear if practiced
  • measuring tape
  • spare gear (monofilament, hooks, tools)
52
Q

Best Catch, Handle And Release Practice for Shark Fishing:

- Step 2: Gear type?

A
  • use non stainless barbless hook. These hooks make hook removal much easier and if left they will corrode and fall off on their own.
  • use rod and reel with a minimum of 80lbs test line monofilament or 80lb test braided line. If possible use 300lb test swivels. This allows the shark to swim when caught preventing entanglement if shark rolls.
  • DO NOT use balloons for tracking fish movement. Balloons mimic jellyfish and can be eaten by other marine species (e.g. turtles0 Floats are a good alt.
53
Q

Best Catch, Handle And Release Practice for Shark Fishing:

- Step 3: Fishing Technique?

A
  • in order to reduce injury and exhaustion to the shark use the following steps:
    1. observe the float(s) at all times, so that the hook may be set quickly
    2. plan your release strategy as soon as the hook is set and make sure tools are accessible and ready
    3. regardless of hook type, set the hook as quickly as possible so that the shark gets caught in the corner of the mouth and not in the gut.
    4. limit fight time as much as possible regardless of hook type, size and gear. If possible, follow the shark and gain the line as much as possible for educe exhaustion of the shark
54
Q

Best Catch, Handle And Release Practice for Shark Fishing:

- Step 4: At Vessel- Handle/Release?

A
  • In order to enhance post release survival of the shark at vessel, use the allowing steps:
    1. Bring the shark to the boat as close as possible. Minimize physical handling. DO not use a gaff to bring the shark closer, as this may severely injure it.
    2. If possible, remove the hook with a dehooking tool. If the shake has swallowed the hook or has been foul hooked ( any place but the haw) cut the leader as close to the hook as possible.
    3. DO NOT hold the shark by its gills. This may cause serious injury or lead to death.
    4. If collecting data, identify markings, sex , size, location, gear used, and condition on release. Also, and if possible, take fork length (FL) and total length (TL) measurements.
    5. If the shark is exhausted, due to extended fight time, revive the shark. To revive it, place a cable behind its pectoral fins, put the boat in idle and swim the shark for a min of 15 mins until the caudal is moving well on it sown. Take care to avoid the gills when putting on and removing the cable
55
Q

Best Catch, Handle And Release Practice for Shark Fishing:

-Step 5: Onboard Handle/Release?

A
  • If you aim to bring the shark onboard, use the following steps to enhance post release survival:
    1. Once the shake is next to the boat, pull the shark up and on the boat horizontally so as to not tear any ligaments, tendons or damage organs
    2. Lay the shark on its side in a soft, shady and wet area. The liver will settle and the shake usually becomes more relaxed. DO NOT squeeze, kick , kneel on or hold the shark tightly.
    3. Out of the water, sharks rogans are very sensitive and become easily injured. A wet towel may also be used to cam the shark down by covering its eyes.
    4. Handle the shake by grabbing its head, midsection and tail as this causes minimal injury. The belly and teeth should always face away from the balder.
    5. Limit air exposure to 3 mins ( ie. shark completely removed from water) any longer and the gills may become damaged. If expire will be longer, ventilate the sharks gills by putting a hose of running salt water in its outh
    6. If the shake is not moving, make sure to revive the shark prior to release
    7. If collecting data, identify markings, sex, size, location, gear used and condition on release. Also and if possible take fork length (FL) and total length (TL) measurements.
56
Q

Shark Tagging?

A
  • can use cattle ear tags…easy identification from a distance
  • kasey tags
  • leave note on tag for identification and info
57
Q

How do we insert tags with a stainless steel needle and 6-8foot hardwood dowel?

A
  • use a scalpel to make incision to gently put tag in near the dorsal fin where there are no nurses..just thick muscle mass so not to damage spine etc….anchor it in 2 inches deep..make hole smaller so it doesn’t come out easily
58
Q

Explain a Satellite tag?

A
  • swivel to a bolt attach a casey tag then insert it into animal so the tag moves freely doff the dorsal fin which doesn’t contact the shark these are good for deep dwelling sharks.
    OR drill a hole into the dorsal fin…(issues: exposed wound to infection etc)
59
Q

SPOT Tags?

A
  • good for sharks that come to the surface a lot…
60
Q

Tagging Animals: Valuable or Violation?

- Tags do pose some?

A

risk to the animals

61
Q

Tagging Animals: Valuable or Violation?

- tagged animals have lower?

A

survival rate in some cases (penguins) interferes with swimming ability…and predator avoidance!
**but is comparable to other forms of mortality ( those are natural forms though)

62
Q

Tagging Animals: Valuable or Violation?

- what can develop?

A 
- infection at insertion sites 
L> shown in marine mammals and sharks
- sterilization issues  
- infection spreads...
**marine environment is so dirty ....healing ability does not help with wounds when tag is placed there..especially with drilling holes ! ( not seen so much with the tags that are just put through with no drill involved)
63
Q

Tagging Animals: Valuable or Violation?

- hydrodynamics?

A
  • has a lot of weight….pulling the dorsal fin back and down bc of drag….. The shark is not slicing through the water was i t should…(could slice through the fin via force?)
  • Could interfere with Dominance displays since they usually swim parallel to one another

Biology 4663: Advanced Elasmobranch Studies (11 decks)

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