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Consider what happens in halibut fishing. A very valuable fish. In 2013 fresh Halibut sold for $22 lb or more at Whole Foods. Generally the Halibut fisheries in Alaska are well regulated. The problem lies in areas outside the designated Halibut fisheries. Salmon trawlers in the Gulf of Alaska are allowed to take 4.4 million lbs. of Halibut as by-catch.

But, there are about 14 million pounds of halibut by-catch in non-halibut fisheries (fisheries beyond the zones of regulation). In other words halibut catch outside of the halibut fisheries is about 3 times that of the regulated fishery. A sustainable fish stock cannot be maintained that way.

As we noted, by-catch waste constitutes needless waste. By-catch discards account for about 300 million tons or (20-25%) of total world catch. David Witherell et al., “An Ecosystem-based approach for Alaska groundfish fisheries”, ICES Journal of Marine Science, 2000, Vol.57, p.772. Such large figures signal that by-catch represents both a significant biological and economic loss to fisheries everywhere. Successful ITQ systems in New Zealand, Iceland and Alaska closely regulate by-catch within commercial fisheries, by requiring that by-catch be a part of the quota owner’s catch for the year. In New Zealand and Iceland in particular, discarding by-catch was deemed a serious violation of the rules of the ITQ system. There, fishermen exceeding their limit due to by-catch have to either pay a fine or buy up someone else’s ITQ. Alaska also significantly ameliorated the threat to its fisheries by allowing sablefish fisherman outside of Alaska’s economic zone to hold both halibut and sablefish quotas. This considerably decreased the discarding of halibut. With conventional licenses and weaker types of regulation, the problem of by-catch discards is pervasive across commercial fisheries. By implementing by-catch regulations. ITQ system can further contribute greatly to more sustainable fisheries.

Other very destructive fishing practices will need to be curbed if fishery resources are to be sensibly conserved. Illegal nets, such as purse seine nets that drag the bottom are used often in tuna fishing. Some of these purse-seine nets are up to one mile long. Heavy damage to the sea (floor) also results. Another destructive fishing practice is use of extremely long-line fishing. In some cases these nets are many kilometers long, with tens of thousands of hooks. Worldwide, long lines kill 400,000 dolphins (porpoises) year.

Trawling for fish has become a significant issue in Europe. The European Parliament has been trying to phase out deep-sea trawling. Bottom gill-netting is an especially serious issue in France and Spain, where by-catch has been 20%-40% of the total. Bottom gill-netting also involves serious damage to the sea floor. So far efforts to restrain this practice have gone nowhere in Europe.

Finally, sustainable fisheries can be promoted by prohibiting, or closing fishing during spawning season (Iceland had 180 such enclosures in 2009).

Questions & Answers

do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Economic development for the 21st century. OpenStax CNX. Jun 05, 2015 Download for free at http://legacy.cnx.org/content/col11747/1.12
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