Tuna are large fish (some can weigh more than
600 kilos), very greedy, excellent swimmers and predators that can reach speeds
up to 90 km/h, but not always, when are eggs these are floating and are at the
mercy of the currents of the Mediterranean, where they find the best conditions
for their development, grow rapidly, its size ranges between 1 and 1.2 mm,
these larvae hatch within 2 days growing up to 4 mm in size, almost in two
weeks are shaped like little fish with all the well-developed structures and in
a month they reach metamorphosis, after which they become a little tuna adults.
The maturation lasts at least a whole year, until young of 1 to 3 years migrate
out of the Mediterranean, then the juveniles remain in the Atlantic where they
can best meet their energy needs. From that time to join adults takes about 5
years to reach sexual maturity (15-30kg / 1m), with the purpose of contributing
in breeding migration.
Every year the tuna fulfil their biological
and migratory cycle characterized by a constant offset, influenced by seasonal
changes, from the cold waters of the Norwegian coast to the Mediterranean warm
as they do not support large temperature changes and seek water with
temperatures above 10 °C. When they arrive to Spain, looking clean or low
salinity and the influence of the full moon waters, they are driven by the need
to spawning, with the wild instinct to preserve their species.
During this trip they go together leading
head by the older one, which reach up to 3 meters long and more than 700
kilograms, and after them come younger and smaller individuals. These predators
need to eat a lot in their inter-player and a fish of 2 meters need to eat 60
kg daily, for which if necessary travel 100 km. to satisfy their appetite.
The "right tuna" coming in May
and June, is a full and glorious tuna, tight and tasty meat summarizing
vigorous blood fat and juicy. During this stage, dominated by the instinct of
reproduction, tuna they have no other concern than reaching its place to start
the spawn. However, there are some other fish that when they start their
migration process, they stop feeding themselves completely, it is not the case
of the tuna, which continues to eat but does not deviate from its path and eat
only what is in its given route. It is what is known as "right emigration".
The "back tuna," lean and weary
from the start, is dried meat and unappreciated gastronomically, are out in
July looking for westward Atlantic waters. In this short period of time they
stop feeding absolutely, losing up to 35% of their original weight.
Those are some of the reasons why the tuna
has a fluctuation hefty price during the different migrant seasons, these are
between 15 and 45 € per kg depending, of course, is also well known that when
the tuna returns with low quality after spawning with no fat and no flavor, we
just have to wait for the season, these are price factor that affects the binding.
There are several record sales, mostly in
Japan, the latter figure in the biggest fish market of the world, the Tsukiji
market, was for 9.75 million yen (about 70,000 euros), the second highest price
recorded in Japan. The piece of 325 kilograms was caught in Tsugaru, between
Honshu and Hokkaido Islands, and came from the port of Oma, in Aomori province.
Parts of
the tuna:
Many sushi lovers are use to call Maguro to
the tuna for sushi and they mention it in a sushi bar like "experts"
in the field, however, is rather a generic word, some Japanese or specialized
suppliers use although the term akami, which literally means red meat and may
be heard much better if they want to show off.
If we take a look closely at a good Itamae
or master sushi chef, we can realizing that he cuts the tuna in a whole different way than other fish, he cuts it into five parts, which in Japanese is known as
oroshi gomai, is done, mostly because of its large size and with the clear
purpose of being able to get a higher productivity, that's a custom and a method or
procedure that has passed from generation to generation over time.
These parts has specific names, the upper
back is divided into three, se-kami (front), se-naka (central part) se-shimo
(back), as for the lower splits ha-rakami in ha-ranaka and hara-shimi. The word
SE, means back, and the word Hara, belly. These cuts are also divided, but is better
to leave it here.
The corresponding fillets to the sides are
cut longitudinally into two halves, the top we all know as back and the bottom
or belly meat which is the famous part called Toro, stands out as a curiosity,
long time ago this part of the tuna was considered cat food, the time has
gained ground, especially in the Western world due to its high fat content
makes it more palatable to our taste, hence it is very much in demand and
consequently unpayable for many sushi lovers, which it can be divided into otoro the most part pale fat and less oily chutoro more pink.
Now every specific cut is used for a
certain type of sushi, it is advisable to use the back for cuts of sashimi and
hosomaki, which in this case would be tekkamaki.
You could visit the National Ocean Tuna Fishery Association (Japan) for more information...