終結魚翅,從我開始
作出承諾

魚翅羹危害我們的海洋

鯊魚會決定整個海洋生態的存亡

: Shawn Heinrichs
魚翅羹危害我們的海洋

鯊魚一旦滅絕,整個海洋生態系統就會失衡

鯊魚與生態系統有著密切的依存關係,鯊魚捕食海洋生物中的老、弱、病、幼物種,保持海洋生態的健全;鯊魚也會影響其他物類的活動和分布,並掠食某些物種,使牠們的總數維持適當平衡。一旦最頂端的掠食者遭滅絕,第二階層、繁殖迅速的掠食者們就會過度壯大,造成更嚴重的混亂和損害。

一項關於美國大西洋中部的科學研究指出:有11種鯊魚物種幾乎算是完全滅絕了,而這些鯊魚所曾經掠食的14種海洋生物中,有12種族群的數目暴增,重創整個生態。

牛鼻魟魚的數量已經失控,從而使得牠們最愛的食物-紅棕色海扇貝-全然消滅。海扇貝漁業一度蓬勃了一百年多年,但是現在早已榮景不再。當前的海扇貝漁獲量僅是全盛期的13%。

鯊魚族群的銳減,在海洋生態系統中造成可怖且和難以預測的劇變。在一項關於珊瑚礁退化的研究中,科學家就發現:鯊魚的數量愈多,牠們就愈能善加保護正在建造暗礁的珊瑚和藻類,使珊瑚疾病減低。當生態系統得以保持完整,例如金曼礁島的野生動物保護區,礁類就能更迅速地從地球暖化所引起的疾病中復原。

sharksonreefs.jpg

 

 

參考資料

1 - Estes, J.A., Terborgh, J., Brashares, J.S., Power, M.E., Berger, J., Bond, W. J., Carpenter, S.R., Essington, T.E., Holt, R.D., Jackson, J.B.C., Marquis, R.J., Oksanen, L., Oksanen, T., Pain, R.T., Pikitch, E.K., Ripple, W.J., Sandin, S.A., Scheffer, M., Schoener, T.W., Shurin, J.B., Sinclair, A.R.E., Soule, M.E., Virtanen, R., and Wardle, D.A. 2011. Trophic downgrading of planet Earth. Science, 333(6040): 301-306.

2 - Myers, R.A., Baum, J.K., Shepherd, T. D., Powers, S.P., and Peterson, C.H.  2007 Cascading Effects of the Loss of Apex Predatory Sharks from a Coastal Ocean.  Science, 315: 1846-1850

3- Sandin, S. A., J. E. Smith, E. E. DeMartinin, E. A. Dinsdale and S. D. D. et al. 2008.  Baselines and Degradation of Coral Reefs in the Northern Line Islands. PLoS ONE 3: 1-11 ; Stevenson, C., Katz, L.S., Micheli, F., Block, B., Heiman, K.W., Perle, C., Weng, K., Dunbar, R., and Witting, J. 2007. High apex predator biomass on remote Pacific islands. Coral Reefs 26: 47-51.

4 - Ferretti, F., Worm, B., Britten, G.L., Heithaus, M.R., and Lotze, H.K. 2010. Pattern and ecosystem consequences of shark declines in the ocean. Ecology Letters, 13: 1055-1071.

5 - Vianna G,M,S., Meekan, M.G., Pannell, D., Marsh, S., Meeuwig, J.  2012.  Socio-economic value and community benefits from shark-diving tourism in Palau: A sustainable use of reef shark populations.  Biological Conservation, 145: 267-277; Vianna G.M.S., Meeuwig, J.J., Pannell, D., Sykes, H., and Meekan, M.G. 2011. The socio-economic value of the shark-diving industry in Fiji. Austalian Institute of Marine Science. University of Western Australia. Perth (26pp).

6 - White, L.  2008.  Sea the value: quantifying the value of marine life to divers.  Msc thesis, Nicholas School of the Environment and Earth Sciences of Duke University, Durham, North Carolina.