Thursday, March 26, 2015

日本鰻資源還是充滿了謎題

日學者指出日本鰻資源還是充滿了謎題

(http://www.fa.gov.tw/cht/PublicationsPubGlobal/)
2015/3
 
        日本東京海洋大學經營管理研究會於2015年1月15日邀請中央大學海部建二助理教授以「認識鰻魚生態」為題舉行演講會,海部助理教授研究河川與沿岸水域日本鰻之生態,也參與國際自然及天然資源保護協會(IUCN)有關鰻屬魚類之評估。海部助教表示:「日本鰻資源減少雖然可能是海洋環境變化、河川與沿岸水域環境變化及人類之消費等原因所造成,但沒有辦法把握親魚之資源量,連放流之實際成果都沒有辦法掌握,研究人員太少了。」依據海部助教之調查顯示,在日本113條主要河川中,沒有妨害日本鰻溯河之橫斷構造物之河川只有3條,而且這3條河川位於幾乎沒有鰻苗溯河之北海道與沖繩地區。因此他表示:「這可能對資源造成極大之影響,今後有必要進一步調查與評估,在英國有類似此種結構物新造之時,有義務建築鰻魚溯河之魚道。」另外鰻魚的生物學特性不像其他生物般在不同水域有不同之個體群,而是在特定水域產卵孵化之仔稚魚分散到各個成育場,到產卵期前才再回歸到產卵場集結。因此鰻魚之復育不像其他有個體群之生物一樣,當一局部水域之個體群有滅絕危機之時,保護另一個健康之個體群,以復育有滅絕危機之個體群,即此一方法並不適用魚鰻魚之復育,而且一旦資源減少,就有滅絕之可能,現在鰻魚資源已鳴起了響鐘,再者,日本鰻一旦其上游之河川的環境已大幅惡化,本來準備溯河之鰻苗可能會大量死亡,所以「不能只針對特定河川環境之維護,必須改善廣河川域之環境才可。」

        有關鰻魚之放流方面,該助教表示:「放流效果及其對既有生態系之影響均不了解,放流稚魚成長慢,以及是否真的是放流之日本鰻等實態無法掌握,另外如果只是因為日本鰻資源減少,所以只針對日本鰻去保育是不行的,應包括河川環境、生態環境平衡之觀點去改善。」

       
(許金漢,摘譯自日刊水產經濟新聞,21 January 2015)

Thursday, March 12, 2015

即便如此,還是想吃鰻魚

即便如此,還是想吃鰻魚

(http://www.nippon.com/hk/views/b01710/?pnum=1)

前所未聞,「一直在吃鰻魚」的漫畫

Roswell Hosoki先生生於1956年,山形縣米澤市人。1983年出道。作品主題多涉及酒和佐酒菜餚。代表作有《酒之細道》(日本文藝社)等。2010年出任山形縣米澤市觀光大使。
烤鰻魚(※1)那種甘甜芬芳的香氣總會令人食慾大增。人們一般會在夏天的「土用丑日(※2)」食用鰻魚,以避免中暑,但據說野生鰻魚的最佳食用時期其實是秋冬季節。如今,只要提到鰻魚,人們總覺得價格昂貴,若是聽說有人整年都在各地品嚐鰻魚,恐怕會感到羨慕不已——「真是太奢侈了!」
此人便是和服店的少東家藤岡椒太郎,只要閒下來,就一門心思地四處品嚐鰻魚。和未婚妻的約會地點也選在鰻魚餐廳,終於有一次被甩了一句「你乾脆和鰻魚結婚吧」,鬧得不歡而散。這位紈褲子弟便是《U》這本漫畫的主角。故事從2010年開始在週刊《Morning》(講談社)上連載了約兩年時間,至今仍為人們津津樂道。總之,這是一個「一直在吃鰻魚」的故事。閱讀時總會讓人食指大動。
《U》單行本全4卷
據說作者Roswell Hosoki先生關注的是「如何在不會散發香味的黑白畫面漫畫世界中讓讀者們產生對鰻魚的食慾」。
「開始連載漫畫後,我便奔赴日本各地採訪,在品嚐當地土生鰻魚,調查整理鰻魚相關所見所聞的過程中,我切實感受到,無論作為一種飲食文化,還是一種生物,它都比我最初想像的更加有趣、更加深奧。」
近年來,人們開始重視「資源保護」,鰻魚市場形勢嚴峻,而Roswell先生依然千方百計地想要繼承日本的鰻魚飲食文化,我們聽取了他的看法。

江戶時代傳承下來的味道與技藝

今天,一聽到「江戶前」三個字,大家都會聯想到壽司。然而,過去提到「江戶前」,想到的卻是鰻魚。據說戰前在東京灣內每年可以捕獲多達300t鰻魚(東京都島嶼農林水產中心)。
Roswell先生說「鰻魚是與壽司、蕎麥麵齊名的江戶食物」。「烤鰻魚的烹飪方法形成於江戶時代,此後幾乎沒有什麼變化。許多餐廳都世代傳承著當年的味道和技藝。由於大家一直保留著傳統的技藝與自己特有的調味汁,自然老字號也就越來越多。」
老字號出品的烤鰻魚的味道關鍵在於世代繼承、不斷完善、越發成熟的調味醬(東京都台東區的「前川」總店/攝影:加藤Take美)
現在,由於養殖用鰻苗(野生鰻線)遭到濫捕,導致鰻魚資源陷入了危機。2014年6月,日本鰻魚被世界自然保護聯盟(IUCN)發布的「紅色名錄」認定為瀕危物種。近年來,鰻線捕獲量銳減導致鰻魚價格不斷高漲,老字號鰻魚餐廳紛紛停業。
「雖然漲價是無奈之舉,但鰻魚餐廳一直在盡力避免漲價。大多數餐廳都會貼出寫著『實在非常抱歉……』的告示。價格太高就沒有客人光顧,價格太低又無法維持經營。店家都在這種糾結之中維持著經營。」
「我也採訪了鰻魚養殖業者,他們的日子似乎比鰻魚餐廳更加難熬。有的索性停業,有的縮小了規模。由於養殖業者和鰻魚餐廳都是專營鰻魚的,所以無法捕獲鰻線即是生死攸關的問題。」

東西部的鰻魚烤法和味道有所不同

開始連載後,他的採訪足跡遍及名古屋、大阪、京都、高知(四萬十川)、福岡等地,最北到了青森,品嚐了各地的本土鰻魚。鰻丼(蓋飯)、鰻重(盒飯)自不待言,還吃遍了素烤鰻魚、鰻魚酒、鰻魚火腿、鰻魚蛋捲等各種鰻魚料理,但據說他還是覺得烤鰻魚才是最經典的鰻魚料理。
「常言道『穿簽練3年,開膛練8年,烤製練一生』,修煉需要花費大量時間,各個烤鰻師傅烹製出的味道也不一樣。在(東京的)池袋有一家店會在吧檯向客人展示鰻魚開膛清理到烤製的全過程,大家可以切身體會到這是一門很不簡單的技藝。」
Roswell先生介紹說,客人來店後,廚師便開始活剖鰻魚、穿簽、烤製。行雲流水般地完成所有步驟、不浪費一分一秒,這也是鰻魚餐廳的「特技」。
各個烤鰻師傅烹製的味道自然不同,而不同地區的烤鰻方法其實也有很大差異。比如,關東地區會先進行不加調味料的素烤烹飪,然後放入蒸籠蒸,最後淋上調味醬烘烤,口感軟糯。而關西地區則沒有蒸的步驟,只是塗抹調味醬後烘烤(地烤),口感爽脆。東西部的開膛方法也不同,關東採用「背剖」法,關西採用「腹剖」法。此外,關東地區將鰻魚開膛後,會切掉頭部,分成幾塊用竹籤穿著烘烤,而關西地區不會去頭和切塊,直接將幾條一起穿在金屬簽子上烘烤。
藤岡椒太郎(《U》的主角)對大阪的烤鰻方法與東京迥然不同而感到驚訝©Roswell Hosoki/講談社

鰻魚必須在鰻魚餐廳裏細細品嚐

當然,野生鰻魚的風味會因生長環境而不同。
Roswell先生稱:「琵琶湖等湖泊的狀態就像是一種魚塘,鰻魚會長得很壯實。野生鰻魚好像無法穿越津輕海峽,青森縣就成了鰻魚生長的最北極限。在青森的下北半島小川原湖內捕獲的鰻魚尤為壯碩,吃起來非常過癮。或許是因為生長環境寒冷,鰻魚需要儲存脂肪吧。」
而「(高知縣)四萬十川水流湍急,這裏的鰻魚身體緊湊,個頭不會太大。鰻魚的餌食也有影響。在四萬十川內,鰻魚吃河蝦等長大,因此肉質也具有獨特風味。」
Roswell先生說「世界上有各種鰻魚料理,但沒有任何一種能夠超越烤鰻魚」
他一面在採訪過程中享用野生鰻魚,一面在漫畫中敘述著各種趣聞,告訴大家牛丼餐廳、便利商店、超市裏售賣的鰻魚等各式各樣的鰻魚也很美味。不過,他表示「自己逐漸改變了想法,隨著鰻線捕撈量銳減,已經不能再說這樣漫不經心的話了」。
「便利商店的鰻魚便當和牛丼餐廳的鰻丼、超市裏售賣的鰻魚價格高得令人驚訝。去年夏天,超市標出了近2,000日圓的價格。牛丼餐廳的牛丼只要300日圓,而鰻丼卻要800日圓,便利商店的鰻魚便當也是如此,中國產鰻魚要700~800日圓,國產鰻魚價格更是超過了1,000日圓。最近我在想,如果要花這麼多錢,還不如咬咬牙到鰻魚餐廳去吃鰻魚,這樣或許能夠遏制濫捕。」

並非僅限於夏季「土用丑」日的食物

據說日本的鰻魚消費量占據了全球的70%。目前,日本、中國、韓國和臺灣都在養殖鰻魚。這4個國家和地區於2014年5月就限制養殖用鰻線數量這一問題達成了共識,並已從11月開始實施。在日本,養殖業者被賦予了上報鰻魚養殖量和出貨量的義務。
Roswell先生認為「絕對有必要開展旨在保護資源的國際合作」。他強調,雖然形勢嚴峻,但為了保護鰻魚資源和支持鰻魚行業,大家還是應該每年去幾次鰻魚餐廳。
「在日本,鰻魚僅僅是在夏季土用丑日這一天受到歡迎,媒體會一窩蜂地報道鰻魚話題,但第二天馬上就無人問津了。鰻魚行業一直在宣傳鰻魚並非夏季食物。養殖鰻魚並沒有明確的最佳食用季節,而野生鰻魚則在秋季到初冬期間蓄積營養,這段時間的野生鰻魚吃起來最為肥美。」

為了盡情享用鰻魚

Roswell先生認為大家每年也可以去幾次鰻魚餐廳奢侈一下。我們向他討教了如何在店裏大快朵頤的「心得」。
「根本的一條,最好趁熱抓緊吃。」不過,烤製鰻魚也需要一些時間。「近來也有越來越多鰻魚餐廳為客人準備了日本名酒。這些店裏還配有豐富的(使用鰻魚材料的)下酒小菜。享用了美酒和小菜後就可以扒拉熱騰騰的鰻重了。」
順便提一句,酒坊、批發商和售酒店等組織的日本名門酒會每年都會評選出「專家推薦的最佳鰻魚佐餐酒」前三名。Roswell先生就是評審員之一。評委們通過品酒後選擇出最適合搭配烤鰻魚的日本酒,據說大分縣的手工釀造純米酒「西關」今年已經連續第9年蟬聯了冠軍。
Roswell先生還有一項關於鰻魚的「慣例活動」,即出席每年10月26日在京都三島神社舉行的鰻魚法事「大放生祭」。這座神社規模雖小,但歷史卻可追溯到平安時代,鰻魚在這裏被視為神的使者受到崇拜。「參加者主要是西日本的鰻魚業界人士。據說神社的宮司(※3)及其家人世世代代都不吃鰻魚。」
像這樣一年一度為食入自己腹中的鰻魚做過法事後,Roswell先生又有了另一件樂趣。「那就是在京都的鰻魚餐廳裏品嚐關西風味的爽脆烤鰻魚。因為在東京是吃不到的。」
(nippon.com編輯部根據2014年10月的採訪內容編輯而成)
標題圖片:蒸軟後淋上調味醬後烘烤的江戶風味烤鰻魚(東京都臺東區的「前川」總店/攝影:加藤Take美)
 
(※1)^ 日本稱「蒲燒鰻魚」,將鰻魚去骨後切成適當長度,淋上以醬油為主的佐料,串上竹籤燒烤而成的日式烹製方法。
(※2)^ 農曆立秋前的18天為夏季的土用丑日,日本人相信鰻魚有改善食慾、增進體力的效果,習慣在這一天吃鰻魚消暑。
(※3)^ 神社的主神官。

Monday, March 09, 2015

Don’t go chasing eel testicles

Don’t go chasing eel testicles:
A brief, select history of Sigmund Freud
 
If you know anything about psychology, you know the name Sigmund Freud.  If you know anything about Sigmund Freud, you know about his theories on the human mind and human development.  If you know anything about one particular theory, his psychosexual theory, you know that you are a repressed sexual being that likely has an unconscious desire to have relations with a mythical Greek King’s mother.  What you may not know, because it’s conceivably ancillary to his greater works, is that it all began in pursuit of 19th century science’s holy grail: “The elusive eel testicles.”
FreudAlthough it is stated, in some annals, that an Italian scientist named Carlo Mondini discovered the eel testicles in 1777,{1} it is elsewhere stated that the search continued up to, and beyond, an obscure nineteen-year-old Austrian’s 1876 search.  It is also stated, that the heralded Aristotle conducted his own research on the eel that resulted in postulations that these beings either came from the “guts of wet soil”, or that they were born “of nothing”. One could say that such results had to come as a result of great frustration, as Aristotle was so patiently deductive in so many other areas, but he is also the one that stated that maggots were born organically from a slab of meat.  “Others, that conducted their own research, swore that eels were bred of mud, of bodies decaying in the water.  One learned bishop informed the Royal Society that eels slithered from the thatched roofs of cottages; Izaak Walton, in The Compleat Angler, reckoned they sprang from the “action of sunlight on dewdrops”.”{2}
Before laughing at any of these findings, one has to consider how limited these researchers were, with regard to the science of their day.  As they say with young people, Freud probably didn’t know enough to know how futile this task would be when he was first employed by a nondescript Austrian zoological research station.  It was his first job, he was nineteen-years-old, and it was 1876.  He dissected approximately 400 eels, over a period of four weeks, and he worked in an environment that the New York Times described as “Amid stench and slime for long hours”.{3}  His ambitious goal was to write a breakthrough research paper on the animal’s mating habits that had confounded science for centuries.  One has to imagine that a more seasoned scientist may have considered the task futile much earlier in the process, but an ambitious, young nineteen-year-old, looking to make a name for himself, was willing to spend long hours slicing and dicing these eels, to hopefully achieve an answer that could not be disproved.
EEL TesticlesUnfortunate for young Freud, and perhaps fortunate for the field of Psychology, we now know that eels don’t have testicles, until they need them.  The ones Freud studied, apparently didn’t need them at the time he studied them, for Freud ended up writing that he had only been supplied with eels “of the fairer sex”.  Freud did, eventually, write a research paper, but it detailed his failure to locate the testicles, and he moved onto other areas as a result.  The question that anyone reading Freud’s later, Psychological theories has to ask, in conjunction with this knowledge, is how profound was this failure on the rest of his research into human sexual development?
Most of us had odd jobs at nineteen that have, in one way or another, affected us for the rest of our working lives.  For most of us, these jobs were low-paying, manual labor jobs that we slogged through for the sole purpose of getting paid.  Most of us weren’t pining over anything, in search of a legacy that would put us in annals of history. Most of us had no feelings of profound failure if we didn’t do well in these low-paying, manual labor jobs.  Most of us simply moved onto other jobs we found more rewarding and fulfilling.
Was the search for eel testicles the equivalent to a low-paying, manual labor job to Freud, or did he believe in this vocation so much that he was devastated when he failed?  Did he slice the first hundred or so open and throw them aside with the belief that he simply had another eel of the fairer sex, as he wrote, or was he beginning to see what had plagued the other scientists, including Aristotle, for centuries?  There had to be a moment, in other words, when he began to realize that they couldn’t all be female.  He had to realize, at some point, that he was missing the same something that everyone else had been missing.  He had to have had some sleepless nights struggling to come up with some different tactic. He probably lost his appetite at various points, and he probably shut out the world in his obsession to achieve infamy in marine biology.  If even some of this is true, even if it was only four weeks of his life, it could reasonably be stated that this moment in his life affected him profoundly.
If Freud had never existed, would there be a need to create him?
Everyone has a subjective angle from which they approach a topic they wish to study.  It’s human nature.  Few of us can view any subject, or person in our life, with total objectivity.  The topic we are least objective about, say some, is ourselves.  And the topic, on which we theorize most, when we theorize on humanity, is most commonly ourselves.  All theories are autobiographies, in other words, that we write in an attempt to understand ourselves better.  With that in mind, what was the subjective angle from which Sigmund Freud approached his most famous theory on psychosexual development in humans?  Was he entirely objective when listening to his patients, or was he forever chasing eel testicles in the manner Don Quixote chased windmills?
After switching vocations to the field of Psychology, did he view the patients that sought his consultation as nothing more than the set of testicles he couldn’t find a lifetime ago?  Did testicles prove so prominent in his studies that he saw them everywhere in the manner that a “rare” car owner begins to see that car everywhere, after driving that “rare” car off the lot?  Some would say that if Freud engaged in such activities, he did it unconsciously, which others could say may have been the basis for his other theory on unconscious action.  How different would Freud’s theories have been if he had found eventually found what was then considered the holy grail of science at the time?  How different would his life have been?  Would he have ever switched vocations, or would he have remained a marine biologist based upon the fame he achieved?
How different would the field of Psychology be, if he had decided to remain a marine biologist?  Or, if he had eventually switched to Psychology, for whatever reason, after achieving fame for being the eel testicle spotter in marine biology, would he have approached the study of the human development, and the human mind, from a less obsessed angle?  Would his theory on psychosexual development have occurred to him at all, and if it didn’t, was it such a fundamental truth that it would’ve eventually occurred, without Freud’s influence?
It can be said, without too much refutation, that many in the world have had their beliefs of human development more sexualized by Freud’s largely disproved psychosexual theory?  How transcendental was this theory, and how much subjective interpretation was involved, and how much of that interpretation was derived from the frustration involved in his inability to find the eel testicle?  Did Freud spend the rest of his career overcompensating for that initial failure?
Whether it’s an interpretive extension, or a direct reading of Freud’s theory, modern scientific research theorizes that most men want some form of sexual experience with another man’s testicles, and if they say that don’t, their lying in a latent manner, and the more vociferously a man says they don’t, so goes the theory, the more repressed their homosexual desires are.
The Williams Institute at UCLA School of Law, a sexual orientation law think tank, released a study in April 2011 that stated that 3.6% of the males in the U.S. population are either openly gay, or bisexual.{4}  This leaves 96.4% of this population that are, according to Freud’s theory, closeted homosexuals in some manner.  Neither Freud, nor anyone else, has put a rough estimate on the percentage of heterosexuals that have erotic inclinations toward members of the same sex that are unconsciously experienced or expression in overt ways, but the very idea of the theory has achieved worldwide fame.  Read through some psychological studies on this subject, and you’ll read the words: “It is possible..,” “certain figures show that it would indicate..,” and “all findings can and should be evaluated by further research”.{5}  In other words, no conclusive data, and all figures are vague, purposely say some, for use by those that are in favor of the homosexual movement that would have you believe that most of the 96.4% that express contrarian views are actively suppressing their desire to not only support the view, but to actively involve themselves in the movement.
Sigmund Freud has been called “history’s most debunked doctor”, but his influence can still be seen in the field of Psychology, and in the ways society views human development, and sexual development, throughout the world.  The greater question, as it pertains specifically to Freud’s psychosexual theory, is was he a closet homosexual, or was his angle on psychological research affected by the initial failure to find eel testicles?  Or, to put it more succinctly, which being’s testicles was Freud more obsessed with throughout his life?

Tuesday, March 03, 2015

全球變遷對鰻魚資源量的影響


 
全球變遷乃指人類活動所導致的自然環境與人文環境的變遷。全球變遷常被視為全球氣候變遷(Global Climate Change)的簡稱,全球變遷可以分為兩個過程體系:物理氣候系統和生物地球化學迴圈。氣候變遷應包括氣候暖化與氣候變異二個重點效應,前者談的是暖化趨勢下的影響,後者著重於短期異常氣候的預測與其對於防災的影響。氣候變遷對海洋生態系的衝擊包括水溫升高衝擊物種的適應存續、海水酸化改變海水的物理及化學特性,降雨改變影響鹽度、溶氧,以及改變洋流流向與湧昇流強度,改變營養鹽分布等,這些改變都可能影響海洋生物正常的生存、生殖,使生產力降低,而其骨牌效應則會影響到整個海洋食物鏈()的組成結構。所謂海洋食物鏈即是生物間能量的流動,能量由海洋生產者(植物或微生物)固定太陽能成有機物的形式開始,經初級性消費者至各級消費者,消費者或生產者死亡後,經由分解者(細菌、微生物)的分解,在成為營養元素,又成為固定太陽能成有機物的過成中必要元素,如此循環不已,亦稱為"營養鏈"有機物被生物從生產者開始被分解利用一次稱為一個級,海洋食物鏈較長常多45級,中多種食物鏈相互錯、互補顯得樣複雜。位於海洋食物鏈的頂端的生物,而食物鏈低層生物數量的增加會導致海洋的浮游生物和植物的負成長,然後等到這些浮游植物低於某個臨界值,接下來可能無法支撐上一層的需要,造成次一級以上生物的生存危機。人類的過度捕撈更惡化此狀況,因為當魚群被捕捉過度時,資源回復力就會變弱,加上海水水溫升高,改變了魚群原有的最適生存條件,族群生殖與生存的能力更形脆弱。水溫的變化,除了影響魚群分布,也會改變季節性魚群的洄游範圍與路徑,直接改變特定地區海洋生態系的穩定,因為食物網的改變。
全球暖化造成海水密度改變而致海流的流速與流量變動。海洋中魚類的受精卵與稚魚,被海流帶往其他海域,浮游期愈長所受的影響愈大,鰻魚苗就是很明顯的例子;世界上幾種主要的養殖鰻魚 (日本鰻與歐洲鰻),其鰻苗資源量嚴重減少,雖原因不明,但是多數認為跟全球氣候變遷及過度捕撈鰻苗有關。鰻魚的生態包含淡水與海洋生態。鰻魚是河流生態的指標物種,代表著棲地環境的健康,以及生物多樣性的指標,河流失去鰻魚,也意味著河流的死亡。而且鰻魚因不同的生活階段屬於不同級的消費者,全球變遷造成水溫升高、海水酸化,影響鹽度、溶氧,以及改變洋流流向與湧昇流強度,改變營養鹽分布等,這些改變都可能影響鰻魚苗的生存、成長與洄游(飄移)路徑、接岸強度,進而影響資源量。日本鰻在馬里亞那群島西側產卵,鰻苗隨著北赤道洋流與黑潮往北漂流至東北亞,聖嬰(El Niño)現象弱化黑潮流勢,反聖嬰(La Niña)化,黑潮流勢影響鰻苗的漂移,數據顯示和臺灣地區鰻苗捕撈量有所關連。鰻魚苗的消化道中並未發現完整的浮游生物,放射性同位素的調查發現鰻魚苗的營養來源主要是溶解性有機物質,推測鰻魚苗是海洋溶解性有機物質循環的一部分,它們扮演移除顆粒性有機碳的角色。海洋的生產者將二氧化碳轉換為有機物質,大部分的有機碳被上、中層的浮游生物及細菌消耗後再利用。黑潮是貧營養的海域,而在貧營養海域細菌呼吸率大約佔當地群聚呼吸率的82%-98%,微微型浮游生物、共生性細菌與基礎碳通量彼此所構成的食物鏈(生物能量流動網)應和鰻魚苗的初期餌料有關,氣候變遷對鰻魚的影響幾乎是多層面的,從淡水生態系的改變導致的成長與下海生殖行為的改變;生殖洄游可能也被影響,雖然目前此假設尚未被證實;海洋溫、鹽的改變確定會影響鰻魚的成熟與產卵,進而影響所生產的子代數目;海洋環境的改變直接和鰻魚苗的食物能量來源和成長發育,漂流路徑,接岸程度等等。日本東京大學大氣海洋研究所2013年提出一份研究報告:指出鰻苗每年不同的增減,可能在氣候變遷下,改變海水鹽度,也造成鰻魚產卵場改變,於是在不同洋流的帶領下,鰻苗順著黑潮北上洋流,來到台灣、日本、中國沿岸,就得以存活,讓鰻苗大增,一旦進入南下洋流,就是死亡。這份報告提供每年鰻苗多寡的可能之因,但是對於鰻苗總體數量的銳減,直指洄游到產卵場的親鰻急遽減少,才是鰻苗銳減的主因。鰻魚、烏魚和鱙魩仔魚漁業的的資源量有週期性變化,控制此變化的,是受其主要食餌(生產者)族群的質量變化影響? 或是海域水文或其他因子的變動所致? 要回答這些問題實在是要由瞭解此海洋食物鏈相對應於物理、化學環境變化之聯動機制上,因此全球變遷對海洋食物鏈結構的影響是直接也是間接的,經由物理氣候系統和生物地球化學迴圈。