提到遊泳健將，大家應該會想起國際遊泳冠軍菲爾普斯，但是他在海裡遊泳，還是沒有它快。而它，就是我們今天的主角，金槍魚。金槍魚，也被稱作吞拿魚，是端著金色AK47的魚，專門提供給各種軍火商蘇式AK，以此提高身價。當然，它並沒有啥金槍，不過身價還是不低，出場費就得給個幾百。今天，小編就帶你走近，金槍魚的世界。
When I mention the famous swimmer, what come to your mind first? Some people may say Phelps, who is the champion of the international swimming competition, but he is slower than the main character when he is swimming in the ocean. Today’s character is tuna. Tuna, if you know the Chinese name of it, it means golden gun. It can provide arms dealers with some soviet style AK47, therefore raises its status—-It is just a joke, but it is expensive actually. If you want to buy a high-quality tuna, you may cost $50. Today, let me give you an introduction of tuna.
金槍魚簡介
A brief introduction of tuna
金槍魚，屬硬骨魚綱，鱸形目，金槍魚科。鱸形目，看到這個目，一些吃貨就會眼前放光，為啥呢？因為它包含了海中最常見的食用魚，比如鱸魚、石斑魚、大黃魚、帶魚……金槍魚也是鱸形目的，所以它跟它們算是遠房親戚，不過它有個突出的特點，它屬於快速遊泳類群，遊動速度可達130km/h，這達到了可以在高速公路上行駛的速度。鱸形目的其他魚類，跟他比起來，遠遠的被甩在後面，就跟龜兔賽跑似的。能達到這個速度的原因是什麼呢？金槍魚本身，有一些適應快速遊動的形態特點，這才讓它們在海中能夠達到這樣的速度。
黃鰭金槍魚(Yellowfin tuna）
Tuna, belongs to Teleostea class, Perciformes order, tunaceae family. When foodies see this order, they will be attracted. The reason is that it contains most of the oceanic species that are normally eaten by humans, such as perches, groupers, large yellow croakers, and ribbon fishes. Tuna is also belonging to the Perciformes order, so they can be relatives, but it has an eminent feature, which is that it can swim very fast, about 130 kilometers per hour. You can drive a car on the highway and reach this speed! Other fishes in this order can not reach this speed, and when they swim together, it is like a running competition between turtle and rabbit. So What is the reason of such a high speed? Tuna has some adaptations which enable it to reach this speed, so let’s learn them.
金槍魚適應快速遊動的特徵
Tuna’s features for high-speed swimming
金槍魚體形呈紡錘形，也稱為梭形，這減小了它在水中遊動時受到的阻力，身體長，體形較粗壯，活生生的一顆魚雷。它肌肉較為健壯，擁有大量的肌紅蛋白，肌紅蛋白的氧飽和度較高，大量肌紅蛋白代表著強大的爆發力和充足的能量供應，它也有著發達的循環系統，有著複雜的血管網絡，新陳代謝相對於其他魚類來說較快，這讓它在水中有著很高的反應速度。它的尾部也較為特殊，尾鰭深叉呈新月形，尾柄兩側各具一個發達的隆起脊，大家可以想像一下飛機的尾翼，與那個形狀較為相似。金槍魚的皮膚與肌肉緊密連接，可以減小在水中遊動時的阻力。金槍魚的魚鱗屬於圓鱗，提高了金槍魚的遊泳速度。因此，金槍魚就像一顆水中的魚雷，能夠達到130km/h的高速。想一想，如果它在水中悶頭衝起來，就是一顆高速飛彈，撞著誰誰倒黴。
藍鰭金槍魚（Bluefin tuna）
Tuna is spindle shaped, also known as fusiform shape, which reducedthe resistance when it is swimming in the water. It has a long body with a spectacular body build, which lets it looks like a torpedo. Its muscles are strong, and they contain a large amount of myoglobin. Myoglobin’s oxygen carrying capacity is great, so it gives tuna a strong explosive strength and ample energy supplies. It also has well-developed circulatory system, which has complex blood vessels net, so the metabolic rate of it is higher than those of other fishes, which enables it to have fast reaction speed. Its tail is special as well. Its is crescent shaped, and each side of the caudal stalk has a developed ridge. You can imagine the empennage of the airplane, which is similar to the tuna’s tail. Tuna’s skin is closely connected to its muscle, so the resistance is decreased. The scales of tuna belong to round scales, which improves the swimming speed of tuna. Thus, tuna is like a torpedo in the water, which is able to reach the speed of 130 kilometers per hour. Imagine that if it swims in ocean with this speed, it will become a high-speed missile. If it crashes any species, this species is unlucky.
金槍魚的分類
Classification of tuna
金槍魚能夠分為6類，其中包括了我們耳熟能詳的黃鰭金槍魚和藍鰭金槍魚，和大眼金槍魚、馬蘇金槍魚、長鰭金槍魚和鰹魚。
Tuna can be divided into six categories, including the well-known yellowfin tuna and bluefin tuna, as well as bigeye tuna, Thunnus maccoyii, Long-fin tuna and bonito.
1.鰹魚：拉丁文名：Katsuwonus pelamis，屬鱸形目，金槍魚科，金槍魚屬。其他五種金槍魚的名字都帶著「金槍魚」的字樣，唯獨鰹魚特殊，它會不會是鯊魚打進來的臥底呢？它是不是金槍魚中的007？請叫它詹姆斯邦德魚。其實，鰹魚也是金槍魚的一種，它對於溫度和鹽度比較敏感，是最喜歡溫暖的金槍魚，對鹽度的要求很高，在鹽度為32%的海水中看不到鰹魚的身影。
鰹魚(Bonito)
1.Bonito: Latin name: Katsuwonus pelamis, belongs to the order perciforme, tuna family, tuna genus. The names of the other five kinds of tuna all have the words "tuna", but the bonito is special. Will it be a spy from shark? Is it 007 of tuna? Please call it James Bond fish. In fact, bonito is also a kind of tuna. It is sensitive to temperature and salinity. It is tuna that likes warm environment. It has a high requirement on salinity. There is no bonito in 32% seawater.
2.黃鰭金槍魚：拉丁文名Thunnus albacares， 屬鱸形目，金槍魚科，金槍魚屬。黃鰭金槍魚最顯著的特點便是它身上的一抹黃色了，這黃色成為了它與其他金槍魚之間的明顯區分特徵。黃鰭金槍魚是金槍魚中資源量較大，產量較大的品種，是料理界的優質材料。黃鰭金槍魚的圖示如上。
2. Yellowfin tuna: Latin name is Thunnus albacares, belongs to the perciforme, tuna family and tuna genus. The most remarkable feature of yellowfin tuna is its yellow color, which is the distinguishing feature between it and other tunas. Yellowfin tuna is a kind of tuna with large resource and large yield, which is a high-quality material in cuisine. The yellow fin tuna is pictured above.
3.藍鰭金槍魚：拉丁文名：Thunnus thynnus，屬鱸形目，金槍魚科，金槍魚屬。藍鰭金槍魚身上的藍色鱗片也成為了它的顯著特徵。藍鰭金槍魚富含蛋白質，是日本料理的頂級食材。圖示如上。
3. Bluefin tuna: Latin name: Thunnus thynnus, belongs to perciforme, tuna family, tuna genus. The blue scales of bluefin tuna also become its distinctive feature. Bluefin tuna, rich in protein, is the top food in Japanese cuisine. As shown above.
4.長鰭金槍魚：拉丁文名：Thunnus alalunga，屬鱸形目，金槍魚科，金槍魚屬。頭較長，體長將近頭長的4倍；胸鰭很長，為鐮刀狀，長度大於頭長，末端到達第二背鰭起點上的垂直線；尾鰭兩側各有3個隆起嵴。背部暗色，腹部色淡，體色均勻。小鰭呈檸檬黃色。
長鰭金槍魚(Longfin tuna)
4. Long-fin tuna: Latin name: Thunnus alalunga, belongs to the perciformes, tuna family, tuna genus. The head is longer, and the body length is nearly 4 times of the head length; the pectoral fin is very long, which is sickle shaped. Its length is longer than the head length, and the end reaches the vertical line on the starting point of the second dorsal fin; there are three ridges on both sides of the caudal fin. The back is dark, and the abdomen is light. The body color is even. The fins are lemon yellow.
5.大眼金槍魚：拉丁文名：Thunnus obesus，屬鱸形目，金槍魚科，金槍魚屬。體長2m，體重150 kg以上，體形與藍鰭金槍魚相似，胸鰭較大，眼較大。體為粗紡錘形，甚粗壯故又稱「肥肚金槍魚」，體前中部為亞圓筒狀，橫切面近圓形，尾部很短；體高、眼大、頭大。
大眼金槍魚(Bigeye tuna)
5. Bigeye tuna: Latin name: Thunnus obesus, belongs to perciforme, tuna family, tuna genus. It has a body length of 2m and a body weight of more than 150 kg. Its body shape is similar to that of bluefin tuna, with large pectoral fins and large eyes. It is also called "fat belly tuna" because of itsthick body. The front and middle part of the body are subcylindrical, with nearly round cross section and short tail. It has a high body, large eyes and large head.
6.馬蘇金槍魚：不得不說，這種魚有個好名字，「馬蘇金槍魚」，這是請馬蘇來代言來提高身價？拉丁文名：Thunnus maccoyii，肉食性魚類，食用鰹魚，還有糠蝦，魷魚等等。這魚還整起自相殘殺來了，你說都是屬於一個目，一個科，一個屬的，相煎何太急啊？大自然就是這麼神奇，它的神奇，你想像不到。
馬蘇金槍魚(Thunnus maccoyii)
6. Thunnus maccoyii: We have to say that this kind of fish has a good name, "MaSu tuna". Is this to ask MaSu to speak for it to raise its price? Latin name: Thunnus maccoyii, carnivorous fish, predates bonito, bran shrimp, squid, etc. This fish has been fighting against each other. Thunnus maccoyii and bonito belong to one order, one family and one genus. Why are them so urgent to fight against each other? Nature is so magical and enigmatic.
金槍魚的營養價值
Nutritional value of tuna
金槍魚肉質鮮嫩，富含維生素A、維生素D、蛋白質、DHA、EPA、也富含甲硫氨酸等人體必需胺基酸，牛磺酸和礦物質含量也十分豐富，是居家旅行食材的不二之選。藍鰭金槍魚和黃鰭金槍魚較為常見，是營養價值很高的食材。
Tuna meat is fresh and tender, which is rich in vitamin A, vitamin D, protein, DHA, EPA, methionine and other essential amino acids. Taurine and mineral content are also very rich, which is the best choice for home and travel. Bluefin tuna and yellowfin tuna are relatively common, which contain high nutritional value.
參考文獻
1.《普通動物學》第4版，劉凌雲，鄭光美編著，摘錄於2020.3.21
2.百度百科，金槍魚，摘錄於2020.3.21
Reference
1.《Zoology》fourth edition, written by LiuLingyun and ZhengGuangmei, quoted on March 21, 2020
2.Baidubaike, Tuna, quoted on March 21, 2020