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鮭魚 大西洋鮭現況比牠們的太平洋遠親更慘

2000年04月28日
Grist Magazine 韋恩科第斯2000.04.12報導;王秀毓 編譯;楊懿如 審校

早在1940年代,想在梅契斯河(Machias River)裡抓隻大西洋鮭(Atlantic Salmon),(這兒說的可是三、四十磅左右,真正夠格的大尾鮭魚),根本不用懂什麼釣竿釣線的竅門,也不需要釣魚客的耐心。不管是用來福槍桿,魚叉還是魚鉤,你需要的只是準頭。


浩浩蕩蕩的梅契斯河

或者,想抓魚的話,河裡一塊夠大的石頭也行。奈特潘乃爾(Nate Pennell)說,「我還記得學生們會用石頭丟魚。從小在緬因州東岸,」靠河的惠特尼村(Whitneyville)長大的他說,「我十一歲的時候,有一次看到一個小孩從橋上丟石頭砸魚,另一個小孩就在下游等著接受傷的鮭魚。有條鮭魚讓那小子受了不少折騰,男孩手肘和膝蓋都流血了。但他還是緊抓著鮭魚,最後終於把魚帶回家了。」

六十年前,英文字poached salmon指的是熟鮭魚,不是現在所謂的盜捕鮭魚(pouched salmon)。那時候,肌肉結實、鱗片閃閃發亮的鮭魚在緬因州下東部的河川裡,多得像天上的烏鴉一樣。魚群在北大西洋待了兩年以上,養肥成大魚,秋天時大批溯游回來產卵,這就是秋天的鮭魚潮。當地人捕捉鮭魚,製成罐頭,賴此過冬。50年代起,每年有許多興奮的釣客群集梅契斯河。這群釣客中包括飛蟲釣法的先驅,例如泰德威廉斯(Ted Williams)、巴德李維(Bud Leavitt)以及李渥夫(Lee Wulff)。這些釣客把河岸擠得水洩不通,給當地居民帶來不少進帳。


潛伏的鮭魚攝影: Gilbert van Ryckevorsel

但,那都是從前的事了。如今,長話短說,野生的大西洋鮭都從緬因州河川裡消失了。而惠特尼村,和緬因州東部其他小鎮一樣,現在只是輝煌時代的遺跡了。

仍住在惠特尼村的潘乃爾說,一直到60年代都還能從河裡抓到一條30磅的鮭魚。根據官方統計,去年梅契斯河鮭魚捕獲量是零,比僅有五條的98年更慘。在東部七條鮭魚河域裡,99年總計只有29條野生鮭魚回來產卵。

誰幹的?

究竟出了什麼事呢?就像玩偵探遊戲一樣,嫌疑犯很多。科學家正密切注意下列這些可能:

河流水質惡化:這些河川上游的分水嶺多為商業木材林和藍莓園。據服務於州立水土保持局的潘乃爾表示,近年來機械化林業使泥沙淤積更為嚴重。除此之外,藍苺農也越來越依賴殺蟲劑。而過去自由流動的泉水(泉水提供河流中適合鮭魚的冷水區)也被棄置,長滿雜草,以致淤積堵塞。

天敵數量增加:天敵中,威脅最大的是海口的海豹和鸕鶿(cormorants)。在緬因州沿岸的這兩種鮭魚捕食者,其數量和胃口一樣大。溯游而上的鮭魚必須在尖喙利齒中衝鋒陷陣,原本就不高的存活率因而更為降低。官方表示,自70年代初期以來,海豹數目已增加了五倍之多,另約有5萬對鸕鶿現在沿岸築巢定居。

格陵蘭島(Greenland)一帶的商業漁人:歷經千辛萬苦往北遷移游到開放海域的鮭魚最後可能還是落進漁網裡。儘管國際公約限制漁獲量以本國消費需要為限,但格陵蘭島上的漁夫每年仍然捕捉1900萬公噸的鮭魚。

全球溫度上升:對喜歡冷水域的大西洋鮭魚來說,海洋溫度上升可能有微妙但深遠的影響。加拿大的鮭魚數目也在減少中,但研究人員發現,在北方較冷的河川中,數量下降較微和緩。

現有最佳計劃:幫助鮭魚的計劃早在1947年開始,當時緬因州成立了大西洋鮭魚潮委員會(Atlantic Sea-Run Commission)(現在的大西洋鮭魚委員會Atlantic Salmon Commission)督導漁業管理。至97年事實證明,搖擺不定的管理計劃成效不彰,於是州政府擬定一項長程復育計畫,希望整合相關各界:伐木業者、藍莓果農、釣客及保育人士,讓他們和生態學家合作復育鮭魚潮。


悠遊的鮭魚群攝影: 吉伯特 瑞肯渥塞

此計劃一開始得到聯邦政府的消極贊同,但去年環保人士提出訴訟,美國內政部受此影響在十一月態度大幅轉變。聯邦官員宣稱鮭魚的困境比原先料想更為嚴重,而緬因州政府的計劃收效太慢。相關單位因此立即展開作業,要將緬因州東部七條河川裡的大西洋鮭列入聯邦瀕臨絕種生物名單中。

在緬因州東部,將鮭魚列入名單的提議卻沒有得到多大迴響。事實上,部分居民的反應就好像內政部長對他們落井下石一樣。

在東馬契斯住了一輩子的喬羅賓斯(Joe Robbins)說,"我每走20哩就有一百萬隻鮭魚,你覺得這叫瀕臨絕種嗎?"羅賓斯是一位熱衷此道的釣客,即將出發前往俄羅斯滿足釣鮭魚的渴望。他說的並非幻覺或異象,事實上,現今緬因州東部海域裡的確有大約一百萬條鮭魚。這些鮭魚生存在42處浮動的魚場裡,分散在緬因州沿岸海灣。

緬因州最東邊的一縣,華盛頓縣(Washington County),深受全州最高失業率及最低家庭收入所苦。然而這地區卻得天獨厚,有養殖鮭魚的理想條件,水產養殖也是當地經濟較為看好的少數幾項之一。當地冬季水溫不會太冷,夏季水溫也不會太熱。水質乾淨,幾乎沒有病媒。此外,這裡還有東岸最大的潮汐起伏。在派塞馬奎狄灣(Passamaquody Bay)潮差可達28英呎,每天兩次潮汐可以帶走魚場周圍廢棄物和多餘的養料。這項產業每年供應餐廳300萬磅的鮭魚,歲收6800萬,同時提供750個工作機會。


緬因州東港的鮭魚養殖場

水產養殖業者表示,將大西洋鮭列入瀕臨絕種名單會在兩方面打擊水產業。首先,為避免逃出魚欄的養殖鮭魚自然繁殖,與野生鮭魚競爭資源,勢必要限制可供養殖的鮭魚品種。目前鮭魚場養殖的是生長迅速的歐洲品種,假若大西洋鮭被列入瀕臨絕種名單,就可能迫使養殖業者改養收益速度慢的本土種。緬因州水產協會理事長麥剛尼哥(Joe McGonigle)說,"這樣每磅生產成本就會增加45或50分"智利或歐洲的養殖場卻不必受同樣的限制。麥剛尼哥補充說,"如此一來我們必定會失去市場競爭力。"

另一個問題則是魚場位置。麥剛尼哥說,"基本上,鮭魚一旦被列入名單,那麼各河川方圓20哩的地方就不能有水產業。"問題的癥結在於,除非出到外海,否則沿岸根本沒有任何地方離這七條鮭魚河域超過20哩,而往外海發展又是完全不可行的辦法。

緬因州的窘境

緬因州州長安格斯金恩(Angus King)及該州國會議員已出面抨擊這項將鮭魚列入保育名單的提議,聲稱這項草率之舉對當地經濟將是致命的一擊。他們所持的論點簡單而悲哀:他們聲稱,野生鮭魚已經絕種,現在什麼也不剩,沒什麼好保育了。


奔游中的鮭魚攝影:吉伯特 瑞肯渥塞

反對此項聯邦列名的人士以含糊的科學資料為根據,聲言如今散佈流域中的少數鮭魚根本不是野生種。他們指出,在州政府推行數十年的河流供養計劃(River Stocking Programs)下,一片好意的計劃推行者在河流裡放養了各式各樣的鮭魚,包括加拿大種(Canadian Salmon),甚至太平洋種(Pacific Salmon)。反對人士表示,經過這麼多年雜交,這些河川裡早就沒有原生種的鮭魚了。

反對者辯稱,如今剩下的只是雜種鮭魚,一半原生,一半外來,牠們和一世紀前那些鮭魚血緣關係很遠。一位反對人士向波特蘭媒體論壇(Portland Press Herald)表示,假使這些雜種鮭魚是狗,請美國犬種學會來也認不出它們的品種。緬因州官方目前正密切進行基因研究好支持他們的反對案。


是野生鮭魚?還是沒人要的雜種?
照片來源:大西洋鮭魚聯盟

由於基因研究的複雜性,部分人士懷疑它除了讓知名科學家對基因資料代表的意義吵個不停外,恐怕不能證明任何事實。支持聯邦政府行動者則堅持,只要相信雙眼所見,不必仰賴厚厚一疊研究資料。他們馬上 指出,當地鮭魚的習性強烈顯示(即使不算完全證明),儘管和人工繁殖計劃引進的外來種共存,當地鮭魚仍然自成一獨立品種。

一個相關例證是:在緬因州河川裡孵育的野生鮭幼魚幾乎固定不變地離開出生河域,在海裡待上兩年才回來產卵。準備產卵時,它們會長途跋涉到出生河流的上游。而在鄰國加拿大,大部分的鮭魚經過一年的遷徙就會回來,並且傾向於在河口產卵。這些不同的行為特徵自從人們第一次注意到鮭魚的特殊習性以來便一直是如此,由此可推論緬因州的鮭魚經歷這一切風風雨雨仍然自成一個族群。

今年夏天,儘管在委員會會議室和生物實驗室裡,這爭議吵得如火如荼,梅契斯河以及本區其他河川沿岸恐怕要跟東部那些沒落城鎮一樣冷清了。在州議會反對下,去年秋天委員會已宣佈州境內全面禁捕大西洋鮭。州議會目前正設法在今年魚季結束前推翻此項禁令。

在此同時,保育人士、官方生物學家和滿懷希望的釣客都將密切觀察這幾條河川,看看今年會有多少大西洋鮭從外海回來。 

也許有個幾隻;也許,什麼都沒有。

The Coast Is Clear -- of Salmon
Atlantic salmon are even worse off than theirPacific cousins

by Wayne Curtis 04.12.00

To catch an Atlantic salmon in the Machias River back in the 1940s -- and we're talking a legitimate salmon here, maybe 30 or 40 pounds -- didn't require a knack with rod and reel, nor even the wily patience of the angler. Mostly what you needed was decent aim with a rifle or pitchfork or jig hook.

The Mighty Machias

Or for that matter, a good-sized river stone. "I remember school kids hitting them with rocks," says Nate Pennell, who grew up near the river in the village of Whitneyville in eastern coastal Maine. "When I was 11, I saw one kid throwing rocks from the bridge and another waiting downstream to catch the wounded fish. That kid took a pretty good beating from one salmon, and blood was coming from his elbows and knees. But he held on to it. He got it home."

Poached salmon had a different meaning six decades ago. Back then, the sleekly muscular fish were as abundant in the rivers of Downeast Maine as crows in the skies. The fall salmon runs meant huge numbers of large fish, many returning to spawn after two years or more of fattening in the North Atlantic. Locals caught and canned the salmon, subsisting on it through the winter. Beginning in the 1950s, the river was beset each year by hordes of excitable anglers, including fly-fishing luminaries like Ted Williams, Bud Leavitt, and Lee Wulff, who would clog riverbanks and swell local coffers.

Salmon layin'lowPhoto: Gilbert van Ryckevorsel

But that was then. Today, to make a long story short, the wild Atlantic salmon have all but disappeared from Maine's rivers. And Whitneyville, like many other towns in far eastern Maine, is just a ghost of what it once was.

Pennell, who still lives in Whitneyville, says that as recently as the 1960s you could pull a 30-pound salmon out of the river. Last year, according to official counts, no salmon at all were caught on the Machias River, down from just five caught in 1998. Only 29 wild Salmon returned to spawn in all seven of the Dow neast salmon rivers in 1999.

Who dunnit?

So what happened? Like in the game of Clue, there's no shortage of suspects. Scientists are eyeing these possibilities:

A decline in river quality.

The upstream Watersheds of most rivers are commercial timberlands and blueberry barrens. Heavily mechanized forestry in recent years has led to more silting, according to Nate Pennell, who works for the state soil and conservation service. What's more, blueberry growers have become more dependent on pesticides. And once free-flowing springs (which create salmon-friendly cold zones in the rivers) have been abandoned, overgrown, and silted up.

A rise in natural predators

-- among them, harbor seals and cormorants. These two salmon-eaters are as common as they are voracious along the Maine coast these days, forcing migrating fish to run a formidable gauntlet of teeth and beaks, narrowing their already long odds for survival. Officials say the number of seals is up fivefold from the early 1970s, and an estimated 50,000 pairs of cormorants now nest along the coast.
Commercial fishermen off Greenland.
Migrating fish that do make it to the open seas and survive the arduous migration north may end up in the nets of the fishermen. Although international agreements have limited the catch to domestic consumption, an estimated 19 million metric tons of salmon are still caught each year by Greenland fishermen.

Global warming.

The gradual rise in ocean Temperatures may be having a subtle but profound impact on Atlantic salmon, which thrives in cold waters. Salmon runs are down in Canada as well, but researchers note that the decline is less dramatic in cooler, more northerly rivers.

The Best Laid Plans ...

Efforts to aid the salmon date back to 1947, when Maine established the Atlantic Sea-Run Salmon Commission (now the Atlantic Salmon Commission) to oversee management of the fishery. By 1997 it was evident that tweaking management plans wouldn't do the trick, so the state crafted a long-range restoration plan. The idea was to assemble stakeholders -- timber and blueberry interests, anglers and conservationists -- and have them work in concert with biologists to revive the salmon runs.

Salmon in the swim of things
Photo: Gilbert van Ryckevorsel

The plan at first gained the stamp of approval of the federal government. But last November, the Department of Interior, spurred by environmentalists who had filed suit a few months earlier, abruptly shifted its position, announcing that the salmon's plight was more dire than previously thought. Maine wasn't acting fast enough, officials concluded, and the agency immediately started the process of placing the Atlantic salmon on the federal endangered species list in seven of Maine's easternmost rivers.

In Downeast Maine, the proposed listing did not go over terribly well. In fact, some residents reacted as if Interior Secretary Bruce Babbitt himself had leaned over a bridge and dropped a very large rock right on them.

"There's a million salmon within 20 miles of me right now," says Joe Robbins, a lifelong resident of East Machias. "Does that sound endangered to you?" Robbins is a committed angler who now travels to Russia to fulfill his passion for salmon fishing. He's not plagued by hallucinations or odd visions. In fact, there are about a million Atlantic salmon in the ocean waters of eastern Maine today. They're contained in floating pens at 42 sites scattered along coves and inlets along the state's coast.

Washington County ---

Maine's easternmost county - is afflicted with the highest unemployment rate and the lowest average household income in the state. Yet the region is blessed with near-ideal conditions for raising farmed salmon, and aquaculture is one of the few bright spots in the local economy. The water's neither too cold in winter nor too warm in summer. It's clean and largely free of pathogens. And it's flushed by the highest tides in the east, which rise and fall as much as 28 feet twice daily in Passamaquoddy Bay, ridding the areas around the pens of waste and excess nutrients. The industry produces an annual harvest of 30 million pounds of restaurant-ready salmon, providing revenues of $68 million and jobs for some 750 people.

Salmon pens in Eastport, Maine

Aquaculturists say that an endangered species listing for the wild Atlantic salmon would destroy their industry in two ways. First, they say, concerns that escaped farmed salmon will breed and compete for resources with the wild fish could lead to restrictions on what types of salmon may be pen-raised. Salmon farms currently use a fast-growing European strain of salmon; a listing could force them to switch to smaller, slower-to-market native broodstock. "It could add 45 or 50 cents per pound to the cost of production," says Joe McGonigle, executive director of the Maine Aquaculture Association. Farms in Chile or Europe wouldn't be subject to the same restrictions, he adds, "so we would effectively be driven out of our own market."

The second problem is of pen location. "What the listing would do is essentially remove all aquaculture from within 20 miles of the rivers," McGonigle says. That's a problem because there is no place along this coast that's not within 20 miles of one the seven salmon rivers, unless you go straight out to sea. And that's just not practical. 

Maine Squeeze

Maine Gov. Angus King (I) and the state'sCongressional delegation have lashed out at the proposed listing, claiming that it's a blunt club that could deal a mortal blow to the region's economy. They've pegged their fight on a simple if melancholy notion: Wild salmon are already extinct, they claim. There's nothing left to save.

Salmon on the run
Photo: Gilbert van Ryckevorsel

Backed with arcane scientific data, opponents of the federal listing claim that the few salmon that straggle into the rivers today aren't wild at all. They point to river stocking programs that the state has managed for decades -- all manner of salmon have been introduced to the river by well-meaning program managers, including Canadian salmon and even Pacific salmon. Over the years, listing opponents say, interbreeding has effectively eliminated the wild salmon once native to these rivers.

The fish that are left, the opponents argue, are from a mongrel horde -- part native, part introduced, only distantly related to the salmon of a century ago. One opponent told the Portland Press Herald that if the salmon were a dog, it wouldn't be recognized by the American Kennel Club. Maine officials are currently poring over genetic studies to bolster their case.

Wild salmon or mangy mongrel ?
Photo: Atlantic Salmon Federation

Genetic studies are so complex that some doubt that anything can be proven at all -- other than the fact that eminent scientists can argue ad infinitum over what the genetic data means. Those in favor of federal action insist that you don't need reams of data - just trust your eyes. They're quick to point out that the behavior of the local salmon strongly suggests -- if it doesn't exactly prove -- that local salmon have remained a distinct species despite the fraternizing with interlopers from the stocking program.

Case in point: Young wild salmon spawned in Maine's rivers almost invariably leave the river and spend two years away before returning to spawn, then swimming far upstream when they return to their natal rivers. Just across the border in Canada, most salmon return after one year's migration, and then tend to spawn near the mouth of the rivers. These varied behavioral traits have been fixed since people first began to notice the singular habits of these salmon, suggesting that Maine's salmon have remained a population apart throughout it all.

While the debate shifts into high gear in committee rooms and biology labs this summer, the banks along the Machias River and other area rivers will likely be as lonely as many of the shuttered Downeast villages. Fishing for Atlantic salmon was banned by the Commission statewide last fall over the objections of the state legislature, which is seeking to reverse the ban before this year's fishing season ends.

In the meantime, conservationists, government biologists, and hopeful anglers will be watching the rivers to see how many of the Atlantic salmon return from the open ocean this year.

It might be a handful. It might be none.

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