Fisheries 2 - Alternatives Flashcards
Overview (8)
Oceans and globalisation Commercial fishing Fao problem Body size Fishing new target Fishing down Cast web wider Digging deeper Using past? Aquaculture?
Overview first 4
Oceans and globalisation
Commercial fishing
Fao problem
Body size
Overview last 4
Fishing new target
Fishing down
Cast web wider
Fishing deeper
(And past / aquaculture)
1.oceans and globalisation Ocean important Scale of problem Fish spp failing? Trends
Create 17% of globally cobsumed animal protein
I overfishing since 19th century
Global
-Billingsgate in east London
Cod Plaice Whiting Hake 2003 stock below recommended M (But healthy for mackerel and haddock)
Marine systems are flatlining and aquaculture is taking up the slack
Increase in aquaculture since 1990s
- commercial fishing
Problems ?
(5)
Mechanical changes
Mesh size - main instrument of regulation but flawed when fills up holes are smaller
By catch 90% hauls are thrown back and non target app
Is starfish
Habitat destruction - trawling is mor damaging than land cleared for forestry
150x area than land for forestry
Ghost fishing lost by nets
7000 of fish nets are lost each year in N Pacific
Nylon nets persist
Gill netting in Ghana
New technology- fish cannot hide
Precision targeting
- Commercial fishing
Describe factory fishing
Highly automated
Larger process on board
Atlantic dawn and Veronica
Largest in world and can stay at sea for over 3 tea
Can hold enough to feed 2 x pop of Ireland
Precision targeting
If fishing grounds
Street view of oceans
New York Bight
3D maps and GPS technology allows identification of fishing grounds
Spotted planes and sonar
Sonar can even pick out individual fish
What is the street view of sea system called?
New York Bight
3D and 2D technology
3.FAO problem
60% of fishes tracked by UN FAO safe
Fully exploited
Over explores
Or depleted
FAo problem facts
Which areas?
Med
Black sea
Greatest need for recovery
FAO
What spp?
4
Bluefin tuna
Swordfish
Red snapper
Ancoveta in Peru
Note swordfish and red snapper are threatened yet still being sold in local fishmonger
FAO
State of fisheries
# fisheries worldwide is still growing In Asia has doubled in just 2 decades
4.Body size
Large body size is correlate to vulnerability to exploitation
Large spp COD and MARLIN
Slow growing so takes decades to recover
Paper about vulnerability to exploitation
Spp examples.
Covariance?
S Jennings
Sharks
Skates
Reef species
Length at first maturity is strongly correlated T.I final body size across 600spp
Shows covariance (big fish breed later)
Skates size detail ?
Brander 1981
3 skates?
Species > 100cm have been extirpated from Irish Sea
Common skate 250cm
long nose skate 150cm
White skate 200cn
What are the new alternatives? 5
New target Fishing down the food web Casting web wider Digging deeper Aquaculture
- new target ?
Example of 3 spo and what happened
Pacific cod - why USA bought Alaska from Russia
BUT is not as prizes or productive as Atlantic cod - not so tasty
Walleye pollock? More lucrative but already overfished
Haddock? Haddock could be new cod, smaller relative and ecologically similar
- Fishing down the food web
What can we go for?
Problem?
Globally we are trimming higher tropic levels
Could get lower levels
BUT requires smaller mesh sizes and
May have negative effect on higher predators by depleting food sources
Lobster
Shrimp
Scallops
Also still potential negative affects
- Casting the net wider?
Problem exclusion zones
90% of world fisheries are now closed off by 200mile net exclusion zones
Casting the net wider
What has exclusion zones led to?
Problem ££?
This has led to increase pressure on developing countries on deep sea stocks
veronuca and Atlantic dawn have visited African and Australian waters
Contentious issue as subsidised by eu
Also problem as need active coast guards but this is expensive and developing countries cannot afford
Tensions and issues
- Digging deeper?
Example spp
Orange roughy
BUT led to rapid collapse of fishery
St Helen’s Hill collapse happened v quickly
Why? Highly vulnerable
Why was the orange roughy and other deep sea spp highly vulnerable to over exploitation?
3
Long gen time
Slow growth - max age 149!!
Small pop size - min pop doubling time is >14 yrs
Is it just the orange roughy? What is the danger
5 deep sea app in Canadian waters
All in decline
Extra problems cod and herring
Again global problem
Historical series for Newfoundland cod
Comparing
1) cumulative catch
2) numbers at sea
Fish taken out of sea increasing
Key species are being fished out of the food web
Final points - using past to infer the future?
2 key qus?
When will we reach critical point that global fisheries become economically inviable?
How will we provide aquatic food supplies in the 21st century? …
Aquaculture?
Single app
Reduces wasteful bycatch
What does fao show will happen in our lifetime
More fishes collapsing
I’d rate maintained
Marine fish will not be commercially viable in our lifetimes
Future…
what are the five S for aquatic food supply?
Sufficient Safe Sustainable Shock proof Sound
Sufficient?
To meet needs and wants of society
Safe
Minimal risk to people and enviro and safe to eat
Sustainable
Food is available NOW and for FUTURE GENS
Shock proof
Resilient to shocks in production systems and supply chains
Sound
Meet
legal standards for animals and people and
ethical expectations of society
