Video 15 Aquaculture and Fish

Video 15  Aquaculture and Fish


hi APES students this is video 15 on
aquaculture and Fisheries so when you think about aquaculture you probably
think about water and maybe fish farming so here’s what a fish farm might
actually look like in Asian and African countries is where most of the animal
protein that they eat is fish so that’s where most of the fish consumption is
there’s been a huge increase in fish farming production and there’s been a
huge decrease in the number of wild caught species mainly because we’re over
harvesting those oh if you go to the grocery store it’s going to be really
really expensive to buy the wild caught fish whereas if you see something that’s
a little bit cheaper it’s probably going to be from a fish farm so this is a
tragedy the common situation remember tragedy Commons is a shared public
resource is being degraded so fish are not anybody’s property they’re out in
the ocean and anybody can get them and so that has led to a 30% crash in our
fish populations meaning that those species have basically completely gone
away so here’s kind of a graph showing you the history of fishing so back in
the 1950s we had nothing that was collapsed or even over exploited most of
our stuff was still under exploited but then we had you know industrial fishing
processes that came about new technology and now we have nothing that is under
exploited anymore so basically everything is fully exploited or
overexploited or it has completely crashed which means it’s collapse and
there’s almost nothing left at this point so here’s what it looks like when
a fish population collapses so here you have sardines and their collapse happen
right around I mean it was happening in about the mid 40s and then in 52 there
was basically nothing when the line hovers around zero and eventually it
will kind of sort of come back up and maybe eventually it can get back to what
it was but the problem now is going to be genetics because you had so few
species and there’s not a whole lot of genetic diversity here the same thing
with the northern Cod so this did not actually collapse until about the 80s
but again species is basically gone so we can
harvest fish with different methods these are all industrial agriculture
fishing methods so we can have fish cages this is kind of like this is your
aquaculture over here a trawler is a net that goes behind a boat and catches them
it can be a bottom trawler also so it can scoop all the way on the bottom of
the ocean and it basically takes the entire bottom with it as it goes you can
do sonar which is sound imaging so we literally beam sound waves down into the
ocean we can see schools of fish and then you can use that to help you catch
them in these nets we can use purse seine fishing which is basically you
send out a net that it would it be cooked it would not be closed initially
but eventually it’s going to close all around and create a bowl for these fish
you can do longline fishing which is imagine like if you’ve ever gone fishing
with your you know one hook imagine a really really long line that has
hundreds of these hooks so that’s kind of what we’re talking about there you
know deep sea cages you have drift nets that basically float along either with a
buoy or another boat is with it and it catches things that way so there’s lots
of different ways that we can harvest our fish I encourage you to either pause
the video and kind of um draw some of these things or go online and print the
powerpoints out which includes this picture because these kind of a lot on
this one and if you don’t have the picture it’s hard to understand these um
so here’s some of the things that we would catch from all these different
things not necessarily really all that important for you in terms of memorizing
but just to kind of think about hey I might eat some of these things on so
tuna is really really popular that’s usually caught with a longline trawling
get salmon that’s my favorite fish shrimp if you like to eat shrimp that’s
going to be from a trawler or from possibly traps but usually traps or
things like crabs and lobster and other like drift netting is going to be you
know other four types of fish so here’s a gill or a
driftnet just kind of a closer look of that and basically the fish are getting
caught in that net here’s trawling so this is what it looks
like if you’ve watched fishing videos you might see that they bring it up with
a net like this and here’s what the bottom might have looked like before and
then after you’ve trawled it’s basically a completely destroyed ecosystem so this
will definitely be decreasing our biodiversity so what are some of the
damages just like we saw from trawling describe destruction of the seafloor
if you trawl along a coral reef or a seagrass bed you are basically
completely riping out that ecosystem you’re catching fish yes but you’re also
catching a lot of other things along with that bycatch is a huge problem with
fishing so by catches eat anything that you don’t want so they’re non-target
species are they’re really really young species that are not going to be worth
catching you have to either throw them back or more like they’re not going to
throw them back they’re just going to die
so these sharks have been caught in some Nets tons and tons of things like
turtles get caught in Nets and this kind of shows you the fishing gear that has
the highest bycatch rate and that’s gonna be long lines charles and gill
nets are the things that catch things the most so again here’s your bycatch by
gear so you have the stripped Rawls along the bottom are saris in the like
open ocean then you have the bottom trial so trawling you can see is a
really terrible one for catching bycatch this will be your long line right here
so that one is pretty high as well dredging and mid-water trawl these are
all gonna be things if you wanted to catch the least amount of bike bycatch
you would do per scene or a gill net um so there’s also some things that you can
do as a Fisher to try to not catch these species there’s been some kind of
engineering behind some of these things and right now we have these nets that
will actually release the turtles if the get caught in them so basically the
shrimp at the turtles are scooped up by that net traditionally they would just
stay in there and the turtles will die but this device actually allows for it
has basically kind of like a out area where the shrimp go through one area and
then somehow they turtle I’m not exactly sure how that works on the turtle goes
through another area and can get out and here’s a picture of it happening over
here so that’s kind of a cool engineering design that we have
developed that allows for things to not get caught if they’re larger so going to
aquaculture now so again aquaculture is either fish farming on land or will get
in the water in just a second so if it’s fish farming on land it’s in made man
tanks man-made tanks and enclosures usually this is going to be things like
catfish salmon carp Cod all those sorts of things
again this is on land somewhere if it’s in the ocean it’s called Mary culture
and this is where it’s out in the ocean we have enclosures or tanks or something
out there so this will be your saltwater fish more than anything and this is a
flounder shrimp oysters that sort of thing can also grow seaweed and kelp and
that’s also marry culture and you can see this is kind of cool how you can see
like the weights down here that are keeping these things set on the ground
so some benefits of aquaculture it is efficient and very cost effective it
requires very little fuel so that’s good it also requires a very small amount of
water so you can fish farm off the coast in this little spot instead of having to
go out and fish in the entire ocean there’s less habitat destruction we’re
not going to be collapsing the species so that’s a really good plus also so
again here’s kind of where we’re doing some aquaculture what species we’re
growing the most so clams and oysters salmon is a really really popular one 41
million pounds of salmon so this has really skyrocketed all throughout the
world and it’s possible that we may not even be catching wild caught
fish in the next 50 years or so or at least if we are it will be kind of a oh
I want a wild caught animal instead of a fish harmed animals so there are some
drawbacks though to everything as we’ve seen in this class one of the biggest
ones is fish feces the waste actually ends up settling in the tank which can
cause a lot of algae to grow and just kind of water pollution dealing with the
fish waste also the feed that we give them ends up being not all of it is
consumed and some of it has stuff in it that doesn’t really need to be out in
the water on so that also meets the ocean water you can spread diseases and
parasite is just like in our CAFO with our confined animal feeding operations
this is basically a sea farm calf oh so things like sea lice can become you know
very bad within the population and then you can also have escapees so invasive
species might you might be growing a species that’s not negative to that area
and then if it escapes it will go out and it will breed with other natives
that are from that area which can cause problems with our biodiversity so again
here’s some environmental risks of aquaculture one of them also is we have
to give the fish antibiotics and drugs because we’re trying to prevent diseases
in the same way that we’re doing with the passo but that can lead to
antibiotic resistance that we’ve seen so you also have things so this is all the
waste down here that you would see and if we have GMO fish well they also can
go out into the wild and maybe they’re better at catching prey than other
native fish and now you’re decreasing the biodiversity that way so if you’re
concerned about this and you want to make sure that okay well how do I know
if the stuff that I’m buying is wild caught or is it gonna be in collapse
soon are we over harvesting those things here’s what you can do there’s a seafood
watch it was published in 2007 it is still going on now and they will label
things they will say here’s best choice here’s a good alternative and here’s
things to avoid so if it’s something to avoid that means that either it’s pretty
much completely collapse or it’s on the verge of
collapsing and so you don’t want to be contributing to buying and
overharvesting that species of fish so stick with your best choices and you
will be good to go all right bring your questions to class

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