• 대한지리학회지
• /
• 제31권3호
• /
• pp.447-468
• /
• 1996

영양부근 반변천이 절단감입곡류를 하여 생신 구유로상에 약 7m 두께의 토탄지가 형성되어 있다. 이 토탄지를 대상으로 boring 자료분석과 화분분석을 실시하여 토탄지의 지형발달과 제4기 식생 및 기후환경변화를 검토하였다. 구유로상(연지와 원당지 일대)에 토탄지가 형성된 것은 주위산지에서 공급된 선상지성 퇴적물에 의해 구유로가 막혀 습지가 형성되었기 때문에 가능했던 것으로 볼 수 있다. 토탄층은 그 특징에 따라 하부층과 상부층으로 구분되며, 이들 사이에는 부정합관계가 있다. 탄소 연대측정자료, 각 화분분대 화분조성상의 특징, 토탄퇴적속도 등으로 볼 때, 하부토탄층은 대략 60,000년 BP경부터 퇴적되기 시작하여 만빙기까지, 상부토탄층은 완신세 중기경부터 거의 현재까지 형성된 것으로 추정된다. boring지점 1(YY1)과 지점 2(YY2)의 토탄층 화분분석결과는 수목류의 우점시기로 대비할 때, 총 다섯개의 화분대(화분대 YYI, YYII, YYIII, YYIV와 YYV)와 12개의 아분대로 구분되었다. 두지점 간에는 퇴적상 뿐 아니라 화분조성에서도 일견 차이가 있다. 즉, 공통적으로 화분대 III이 존재했으나 화분대 I, II는 주상도 YY1에서만, 화분대 IV와 V는 주상도 YY2에서만 나타났다. 하부토탄층은 화분대 I, II, III시기를 포함하며, NAP시기로서 쑥(Artemisia)속, 오이풀(Sanguisorba)속, 미니라과(Umbelliferae), 벼과(Gramineae)와 사초과(Cyperaceae)등 초본류의 비율이 월등히 높고, 한냉기 수목으로 출현하는 가문비나무(Picea)속, 소나무(Pinus)속, 자작나무(Betula)속 등의 목본류를 포함하며, 이들 목본류의 절대화분량은 상부토탄층에 비해 극히 적어 산림밀도가 낮은 Wurm빙기의 식생경관을 나타내었다. 상부토탄층은 화분대 IVb, V시기를 포함하며, AP시기로서 Pinus와 Quercus 등이 높은 비율로 나타내고 절대 화분량도 많아, 홀로세 온난기의 삼림경관를 나타내었다. 각 화분대 및 아분대 우점수목의 기후환경에 대응하는 생태적 특징으로 작성한 가상 기온변화곡선의 내용은 다음과 같다: 화분대 I은 Butula우점기로서 약 57,000년 BP까지 형성되었으며, 상대적 한냉기로 간주된다. 화분대 II는 EMW우점시기로서 $57,000{\sim}43$,000년 BP에 형성되었으며, Alt Wurm에서 mittel W${\"{u}}$rm으로 전환되는 Interstadial로 간주된다. 화분대 III은 43,000~15,000년 BP간의 가장 오랜 시기를 포함하며, mittel Wurm${\sim}$Jung Wurm기에 해당한다. 한냉기인 화분대 III시기 중에는 Betula, Pinus, Picea 등의 목본류가 교대로 우점하는데, YY1에서 Quercus 와 Picea의 화분조성 변화로 볼 때 아분대 IIId시기가 가장 한냉하였을 것으로 추정된다. 화분아분대 IVa는 하부 화분대와 상부 화분대간의 전환기층으로서 피나무(Tilia)속 우점기로 나타나며, Holocene에 해당하는 화분대 IVb와 V는 약 7,000년 BP부터 현재까지 식생변화로 각각 Quercus와 Pinus가 우점하는 시기로 한국 동해안의 曺(1979)의 화분대 I과 II에 각각 대비된다. Bartlein et al.(1986)의 diagram을 통해 볼 때, 영양지역의 Wurm빙기 최성기의 7월 평균기온은 현재보다 약 10${^\circ}$C 더 낮았을 것으로 추측된다.

• 수산경영론집
• /
• 제34권2호
• /
• pp.75-90
• /
• 2003

When we think of fundamental problems of the aquaculture industry, there are several strict conditions, and consequently the aquaculture industry is forced to change. Fish aquaculture has a structural supply surplus in production, aggravation of fishing grounds, stagnant low price due to recent recession, and drastic change of distribution circumstances. It is requested for us to initiate discussion on such issue as “how fish aquaculture establishes its status in the coastal fishery\ulcorner, will fish aquaculture grow in the future\ulcorner, and if so “how it will be restructured\ulcorner” The above issues can be observed in the mariculture of yellow tail, sea scallop and eel. But there have not been studied concerning seabream even though the production is over 30% of the total production of fish aquaculture in resent and it occupied an important status in the fish aquaculture. The objectives of this study is to forecast the future movement of sea bream aquaculture. The first goal of the study is to contribute to managerial and economic studies on the aquaculture industry. The second goal is to identify the factors influencing the competition between production areas and to identify the mechanisms involved. This study will examine the competitive power in individual producing area, its behavior, and its compulsory factors based on case study. Producing areas will be categorized according to following parameters : distance to market and availability of transportation, natural environment, the time of formation of producing areas (leaderㆍfollower), major production items, scale of business and producing areas, degree of organization in production and sales. As a factor in shaping the production area of sea bream aquaculture, natural conditions especially the water temperature is very important. Sea bream shows more active feeding and faster growth in areas located where the water temperature does not go below 13∼14$^{\circ}C$ during the winter. Also fish aquaculture is constrained by the transporting distance. Aquacultured yellowtail is a mass-produced and a mass-distributed item. It is sold a unit of cage and transported by ship. On the other hand, sea bream is sold in small amount in markets and transported by truck; so, the transportation cost is higher than yellow tail. Aquacultured sea bream has different product characteristics due to transport distance. We need to study live fish and fresh fish markets separately. Live fish was the original product form of aquacultured sea bream. Transportation of live fish has more constraints than the transportation of fresh fish. Death rate and distance are highly correlated. In addition, loading capacity of live fish is less than fresh fish. In the case of a 10 ton truck, live fish can only be loaded up to 1.5 tons. But, fresh fish which can be placed in a box can be loaded up to 5 to 6 tons. Because of this characteristics, live fish requires closer location to consumption area than fresh fish. In the consumption markets, the size of fresh fish is mainly 0.8 to 2kg.Live fish usually goes through auction, and quality is graded. Main purchaser comes from many small-sized restaurants, so a relatively small farmer and distributer can sell it. Aquacultured sea bream has been transacted as a fresh fish in GMS ,since 1993 when the price plummeted. Economies of scale works in case of fresh fish. The characteristics of fresh fish is as follows : As a large scale demander, General Merchandise Stores are the main purchasers of sea bream and the size of the fish is around 1.3kg. It mainly goes through negotiation. Aquacultured sea bream has been established as a representative food in General Merchandise Stores. GMS require stable and mass supply, consistent size, and low price. And Distribution of fresh fish is undertook by the large scale distributers, which can satisfy requirements of GMS. The market share in Tokyo Central Wholesale Market shows Mie Pref. is dominating in live fish. And Ehime Pref. is dominating in fresh fish. Ehime Pref. showed remarkable growth in 1990s. At present, the dealings of live fish is decreasing. However, the dealings of fresh fish is increasing in Tokyo Central Wholesale Market. The price of live fish is decreasing more than one of fresh fish. Even though Ehime Pref. has an ideal natural environment for sea bream aquaculture, its entry into sea bream aquaculture was late, because it was located at a further distance to consumers than the competing producing areas. However, Ehime Pref. became the number one producing areas through the sales of fresh fish in the 1990s. The production volume is almost 3 times the production volume of Mie Pref. which is the number two production area. More conversion from yellow tail aquaculture to sea bream aquaculture is taking place in Ehime Pref., because Kagosima Pref. has a better natural environment for yellow tail aquaculture. Transportation is worse than Mie Pref., but this region as a far-flung producing area makes up by increasing the business scale. Ehime Pref. increases the market share for fresh fish by creating demand from GMS. Ehime Pref. has developed market strategies such as a quick return at a small profit, a stable and mass supply and standardization in size. Ehime Pref. increases the market power by the capital of a large scale commission agent. Secondly Mie Pref. is close to markets and composed of small scale farmers. Mie Pref. switched to sea bream aquaculture early, because of the price decrease in aquacultured yellou tail and natural environmental problems. Mie Pref. had not changed until 1993 when the price of the sea bream plummeted. Because it had better natural environment and transportation. Mie Pref. has a suitable water temperature range required for sea bream aquaculture. However, the price of live sea bream continued to decline due to excessive production and economic recession. As a consequence, small scale farmers are faced with a market price below the average production cost in 1993. In such kind of situation, the small-sized and inefficient manager in Mie Pref. was obliged to withdraw from sea bream aquaculture. Kumamoto Pref. is located further from market sites and has an unsuitable nature environmental condition required for sea bream aquaculture. Although Kumamoto Pref. is trying to convert to the puffer fish aquaculture which requires different rearing techniques, aquaculture technique for puffer fish is not established yet.