Country, Technology And Market: A Research On The Causes Of Marine Fish Population Structure Change In Taiwan Strait (1492-1966)

Generally, a large marine fish population may develop to a small one graduallyand the small population is easier to decline for the limits in the number of fishindividuals which caused by the random fluctuations of population quantity andstructure. The marine fish resources is abundant along the coast of Fujian and Taiwanprovince. And the biodiversity in these fish grounds is very complex too. However,seeing in the long-term study angle, the changes of natural environment, humanimpact and the variation of marine fish population itself would lead to the randomfluctuations of population quantity and structure.Every winter, the western coast of Taiwan was famous for the gray mullet fishery.Although the fishing season and migratory routes was stable, the distribution of somekey fishing grounds ever changed for the variation of ocean current. However theimpact to the change of fish population structures which had caused by the variationof natural environment in Ming and Qing dynasty was not distinct along the coast ofTaiwan Strait. But The impact of human factors had taken a very important role.As for the human factors, we should consider the changes of national marinepolicy first. Since the earlier Ming dynasty, the fisherman’s fishing activities wereunder the control of the government along the coast of Fujian province.Most of theislands where many kinds of fishes always gathered in there ever became the mainfishing ground in the late Ming dynasty. However the administration and control ofthese islands was very strict for the political and military reasons in Ming and Qingdynasty. This policy not only delayed the developing process of these islands, but alsoprotected the local fish resources objectively.In terms of the main commercial fishes, the key factors that would impact thepopulation quantity and structure still comes from human reasons.The hairtail, largeyellow croaker and red porgy were one of the most important commercial fishes in theTaiwan Strait in the past years. The hairtail was one of a large amount marineproducts since late Ming dynasty. Both the change of social system and fishingtechnology could impact the fluctuations of the quantity of hairtail resources. But thechange of the range consume market would be the most important factor. After1950s,the unbounded over-fishing had caused the decline of hairtail fishery along the coastof Fujian province under the pressure of ever-increasing consuming demands.The large yellow croaker was one of the most important commercial fishes inFujian province since the late Ming dynasty. For the limits of fishing instruments and landform of the fishing ground, different fishing nets were invented in different largeyellow croaker fishing grounds. The quantity of large yellow croaker resources didnot fluctuate dramatically until the discovery of overwintering ground in early1960s.The resources of red porgy was abundant along the coast of Fujian province inthe Ming and Qing dynasty. As the impact of fishing effort was very light and thediscovery of east China sea local population was late, the quantity of red porgyresource was relative stable.The fatal impact to the red porgy population was thediscovery of wintering ground near the Pescadores Islands in1937.It is noteworthy that, although some mordern fishing companies appeared oneafter another in the early1930s, these prosperity was short-lived. They went bankruptquickly for the bad management even if they had equipped steam vessel and othermordern fishing gears. From then on, the traditional Chinese fishing gears were stilldominant along the coast of Fujian province.Compared with the situation in the traditional era, the fishing boats, fishing gearand technology, even the main fishing ground did not make obvious advance in1950s.By analysing some related archives kept in this time, it could help us to get a clear andbetter undersdantment of the fishing structure and commercial fish species in the past.From1950to1960, both the fishing structure and the main species of commercialfishes had dramatic changes compared to the past along the Dong shan Island whichlocated in the centre of southern Fujian fishing grounds mainly caused by the changesof human factors.The index of the individul’s body length, body weight and age is usuallyregarded as the main basic biological facotrs that could reflect to the population’squality and structure in the marine ecosystems. By analysing some records kept in thelocal chronicles and other ancient documents, the changes in the marine fishpopulation structure had been revealed by a long-term study. Compared with thebiological investigation materials which acquired in1950s and1960s, the body lengthof dominant group of most large fishes were much longer; some small fishes such asmudskipper and tapertail anchovy, their body length of dominant group did not haveobvious changes. However as some large fishes’prey, the body length of dominantgroup of the golden small sardine was shorter for the disappear of main predators.All in all, the impacts of social system, fishing technology and consume marketwould be the most important factors which could impact the marine fish populationstructure and the quantity of fish resources during the past500years. However theimpact of the change of natural environment to the variation of population structurewas not very notable. The function of market was more important under thebackground of national industrialized progress since1950s. The ever-increasingconsume demands had promoted the improvement of fishing technology. Theoverfishing had caused the decline of some main commercial fish resources and thedegeneration of marine Eco-system.