Flashcards in Fisheries and conservation - Part 2 Deck (44):
What is the basic idea of a marine reserve? How is it controversial?
The basic idea is to set aside large chunks of water as a reserve to act as a source.
It is controversial politically but proven scientifically.
Describe in more detail a marine reserve.
Fish can be caught outside the reserve but cannot be caught inside it.
Inside, it acts as a source because the fish in the reserve are allowed to grow and spawn.
These baby fish will then migrate.
So, even if there is high fishing pressure outside the reserve, there is still a source population to replenish that fishery.
Are marine reserves exclusive to marine waters?
No, they just originated there.
How is diversity of fish species affected by a marine reserve.
Obviously, within the reserve it is increased but, it also increases outside the reserve.
How does fish catch fare when a reserve is established.
What is CPUE and, how does this get affected by a marine reserve?
Catch per unit effort
So, describe the benefits of a marine reserve.
Fish catch is increased outside the reserve.
Diversity increases both inside and out of the reserve.
CPUE is increased.
Fishery is more stable and there is increased ecotourism on the reserve area.
With all these benefits of marine reserves what could possibly be the downside?
They are controversial politically.
Placement of reserves is extremely critical because it limits local fishermen living nearby.
Enforcement is difficult.
Where are marine reserves generally located?
In sites with the right nutrients, structure or spawning locations.
Describe the enforcement issue and what progress has been made.
Some marine reserves can be quite larger (Ex: Australian Barrier Reef) and, the coast guard is generally not that large.
Recently, google has been able to track via GPS boats that are in protected waters and locals can call the police if they see someone fishing in protected waters.
Describe the collapse of Atlantic Cod in Canada.
Cod have the characteristics of a fish that should not be overfished.
However, there was a worry that the fishing pressure was starting to exact a toll on them.
The English decided to commision a study led by Thomas Huxley who decided it was impossible to overfish cod.
This remained the official position of the Canadian government until the late 80s.
Fish that were getting caught were smaller and there were less of them.
Catch rates were increasing, solely due to increased efficiency in harvesting practices.
1990 - first regulations on cod
1992 - first even moratorium on cod fishing anywhere in Canada
1994 - entire cod fishery in Canada collapse
Still no Cod fishery today
Are sturgeon susceptible to being overfished?
Adults mature around 25 years of age and spawn every 3-4 years so, yes.
Where does most caviar come from?
How was sturgeon sustainably fished?
Soviet Union and Iran realized the economic value and imposed fishing regulations to prevent overfishing.
How did sturgeon get overfished in the Caspian sea?
Soviet Union fell apart.
New countries were having issues with any regulations leading to a free for all in the Caspian.
No regulation outside of Russian/Iranian waters.
Where do sturgeon spawn relative to the Caspian Sea?
Spawn in rivers off the Caspian, inland.
At about the early 2000s, the sturgeon population started to decline. Thus begun tight regulations but, the population was still crashing due to individual countries being unable to regulate their fishery.
What was done to prevent the fisheries crash?
Started working with CITES - convention on international trade of endangered species.
They could not control what a country did but could control where caviar was being bought.
At one point, countries that signed with CITES banned import altogether.
This relieved the heavy fishing pressure.
Sturgeon on the rebound due to tight regulations.
What has happen to the ban on import of caviar since then?
Been relaxed, some import is still allowed.
During the ban, one company was allowed to sell caviar. Describe this.
Company in Canada had sturgeon farm in tanks.
Cites agreed to allow them to sell it.
What are some of the reasons for shark population decline?
Shark fin soup (biggie)
Describe how sharks can or cannot be overfished.
Sharks grow slowly, reproduce slowly and only have a few offspring.
What is the major reason for shark decline?
Why is shark finning so hard to regulate?
Sharks take up lots of space so they will cut off the fins and toss the fish back.
Hard to estimate total numbers and hard to determine which species it came from.
Easier to hide fins especially when a company does it.
What was done to help alleviate the issue of shark finning?
Banned importation of shark fins.
Canada and US banned the importation of shark fins.
What is a reason that rays are starting to get endangered?
Rays have the same cartilage as sharks so, fishermen will catch rays and cut out a shark fin shape.
What are other fish that were overfished?
Describe overfishing and eels.
Used to be a common fishery source in NA and EU.
Now overfished and rarely sold.
Spawn in ocean but we dont know much of its reproductive status.
Describe overfishing and swordfish.
Still an issue.
Top predator that grows slow.
Used to be common on restaurant menus but vastly overfished now.
When would it be better to eat swordfish?
If it was caught in Canada or the US where they use more selective catch methods.
Descibe overfishing and the Chilean seabass.
How was it pushed off of menus?
When looking for a new species to fish, commercial fishers started fishing for toothfish.
We knew nothing of its life history traits but it appeared in restaurants everywhere as a fancy dish.
However, within 2 years, it was being overfished.
So, a major media campaign was launched to shame restaurants serving it.
Why was the media campaign necessary for regulating chilean seabass catches?
Caught out of EEZs so no regulation could be imposed.
Where was chilean seabass caught?
Off the coast of central america in cold water.
Describe cascade effects?
Overfishing of top predators which provide top-down regulation to underlying trophic levels can lead to disastrous effects in an alternating fashion down the food chain.
Why are cascade effects prevalent with overfishing?
We prefer to eat piscivorous and thus top predator fish.
These are big, easy to catch and tasty.
Describe how clams fall into cascade effects.
Hammerhead shark decline led to no top down regulation on ray populations which voraciously fed on clams, reducing population numbers.
What is the general consequence of overfishing predatory fish?
Prey fish explode in numbers and greatly affect lower trophic levels and ecosystems such as reefs or grass beds.
What is bycatch?
Catching species other than the target species.
i.e. bycatch in a fishery is catching anything other than the fish of interest.
Why is bycatch an issue, regulation wise?
Only what is kept on the boat is reported, all by-catch is thrown overboard, even if dead.
Describe shrimp fishery bycatch and how this was relieved.
Used to be that for every lb of shrimp, there would be 2-10lbs of bycatch.
Nets that they would use would catch anything in their way.
This included sea turtles.
Public outcry led to development of TED - turtle exclusion device.
What is a TED?
Gate that allows turtles caught in a shrimping net to escape.
How did TEDs help the shrimp fishery?
Caused change in gear-type to increase specificity. Didnt really affect numbers of shrimp caught.
Helped satisfy the public.
Describe the tuna bycatch issue.
The way tuna is caught is by following dolphins to find tuna schools and then throwing out a purse seine to catch them.
The issue, was that dolphin would get caught and die.
How was the dolphin by-catch solved?
Installed floats in purse seines that would sink a few feet to allow dolphins to escape the net.