Conservation

Question 1

where have no take zones been a success?

Answer 1

area east of Lundy island - draft report shows no 3x more lobster in this area compared to outside the zone
enhanced fish and shellfish in the area
greater catches for fisherman outside the area
increasing wealth of marine life
increasing benefits to local tourism

Question 2

what is zoning the ocean?

Answer 2

multi use zones such as the great barrier reef, including preservation, wilderness, scientific, fishing extr.
different parts of the area have different zones

Question 3

why are reserves difficult in freshwater environments?

Answer 3

hard to conserve whole watershed
sediments and pollution washed down into protected areas
dams built in, may stop fish entering watershed

Question 4

what is stock enhancement?

Answer 4

release of captivity raised fish into the wild stocks of the ocean. management tool used to restore depleted species
first started in the 1800s

Question 5

when has it shown to be unsuccessful however?

Answer 5

Kristiansen et al 1997 released 18 milion cod larvae into a fjord in Norway
larvae genetically marked, making it possible to distinguishe hatchery from wild
Mortality rate was very high
only 120 estimated to have survived`

Question 6

why would hatchery raised fish be more unsuccessful?

Answer 6

hatchery raising promotes changing in phenotypes associated with reduced fitness
cultured fish proportionally smaller fins and deeper bodies
hatchery environment causes evolutionary change (Fleming et al 1996)
Hatchery fish do not experience food shortages! food pellets reduce role of learning

Question 7

give an example of differences in foraging ability when comparing hatchery and wild fish stocks?

Answer 7

learning allows prey recognition and handling efficiency
e.g. Atlantic Salmon,
wild fish would choose Hydropsyche
Naive hatchery reared ate low % of Hydropsyche but became more selective with experience
Reiriz et al (1998)

Question 8

what happens when hatchery reared fish start to feed?

Answer 8

usually take up risky positions near water surface
energetically costly positions - regions of high flow
positions near other fish -dispersal failure

Question 9

why are hatchery reared fish limited in respect to predator avoidance?

Answer 9

poorly developed anti predator behaviour
insufficient to cope with life in the wild
e.g. flatfish
Kellison et al 2000 found that anti-predator behaviour of hatchery-reared flounder was poorer than wild fish
ALSO juvenile salmon, reared in high densities shared shelters more than in wild fish
may be costly to hathchery fish