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The Bluefin Tuna
Extinction PowerPoint
By Eric Nguyen
Introduction
A common quote used is “there are plenty of fish in the sea,”
however due to overexploitation, this quote may not have the same
meaning as it will over the next few years. For this and other reasons
I chose to research fish for this assignment and more specifically, the
Bluefin tuna.
For centuries, tuna and fish in general have been an
important component to peoples diets and as the human population
grows, there are more mouths to feed. However the fish population
can not keep up with the demand and so over the years the fish
population of Atlantic and Southern Bluefin tuna have dropped
significantly which not only affects us but the entire food chain.
Types of Bluefin
*Measurements are maximums
Southern Bluefin Tuna
Length: 8.2 feet
Weight: 570 lbs
Location: Southern
Hemisphere – Indian
Ocean commonly
Pacific Bluefin Tuna
Length: 9.8 feet
Weight: 990 lbs
Location: Northern
Pacific Ocean, but
have migrated south
Atlantic Bluefin Tuna
Length: 8.2 feet
Weight: 551 lbs
Location: Northern
Atlantic Ocean and in
Mediterranean Sea
Facts
• Their exterior colours help camouflage them from above and
below. The top of their bodies are dark blue and the bottoms are a
silver-white.
• Their torpedo shaped bodies make then one of the fastest fish
going ay 70km/hour
• They live for around 15 years, but some are believed to be up to
50 years old
• Their core body temperature can be maintained even when the
temperature surrounding them changes. This allows them to still
be efficient when being chased, hunting or when migrating. They
can go as deep as 600m but at night they swim at about 50m.
Diet
Bluefin tuna are carnivores and their
diet regularly consist of small fish and
invertebrates such as herring, sardines, squid,
mackerel and crustaceans.
In aquaculture, they are fed small frozen
pelagic fishes. However research is being done
to develop a less expensive way to feed the fish.
The problem is that whatever the fish eats
affects its taste, therefore it makes this difficult.
The Bluefin tuna is very important in our diets. Not only
does it come in large quantities around the world, and is considered among
Japanese and Western chefs to be the best raw fish in the world. Bluefin
tuna meat is often found I sushi and sashimi.
Going Extinct
The main cause of the Bluefin tuna going extinct is overfishing
throughout the world. Their large quantity, price and taste has brought a
large demand to the fish market especially to Japan. Estimates say the
Southern Bluefin tunas population has decreased by 92% and the Atlantic
by 90%.
Their peak price in 1990 was at $34 per kilogram, the typical fish
would then sell for around $10 000. Since then of 2008, it is now around
$23 per kilogram. The decrease is due the large supply of fish being caught,
however the extras are easily frozen and sold in stores without losing their
taste.
Bluefin tuna are not only prised by their taste but also because of
their features. Recreational fishers like to also catch Bluefin tuna as they are
enormous and fast, creating a more challenging catch.
Prevention
For years, the Bluefin tuna has IUCN Red list of Threatened species as
Endangered and even Critically. Recently they’ve been added to red list of
Greenpeace International.
Countries have taken some action as organizations such as the
Commission for the Conservation of Southern Bluefin Tuna and the International
Commission for the Conservation of Atlantic Tunas were created. They’ve been
able to reduced the total allowable catch globally from 11 810 tonnes to 9 449
tonnes for the Southern Bluefin tuna. However these restrictions can even create a
larger demand for these fishes causing illegal fishing markets to form.
Aquaculture is also a method that helps the tuna population. On the
other hand it also affects it negatively as wild Bluefin tuna are also brought into
the pens before they are able to reproduce.
In 2009, using hormonal therapy there were able to create complete
aquaculture allowing for the reproduction of Bluefin tuna without wild ones.
Affecting Ecosystems
• It distorts the entire food chain practically destroying the physical
environments of the ocean.
• It could affect fisheries making them close down and destroying the
economy and fishing business. This can be avoided with sustainable
fishing.
• All marine life rely on each other, and so specifically fishing for one type
such as the Bluefin tuna will ensure its extinction along with others in
the after effects.
• Unintentionally killing Bluefin tuna and other species of marine animals
due to lost nets or long line fishing increases the rate at which they go
extinct.
• Pollution due to garbage or chemical spills not only kills the fish but the
ecosystems at the same time.
Affecting Humans
• Biodiversity – Fish being so important to not only humans but other
animals, making them extinct can destroy the diversity among marine life,
especially since fish have been here the longest
• Ethical – Overfishing is not only the case of the Bluefin tuna but also of
many other marine animals. The marine animals are being caught in cruel
ways sometimes unintentionally too. They’re even caught for recreational
purposes.
• Social – It may cause world debates and conflicts on the conservation of
marine animals as it is a huge market.
• Esthetic – It shows how careless we are with the worlds limited resources
• Economic – The fishing industry is on e of the largest markets not only for
food but for money. Its ethically good to not over fish but because fishing
can create so much revenue, poor countries especially are not willing to let
it go.