COMMUNITY STUDIES ON THE BIOLOGICAL PRODUCTION PROCESS OF MYSID INHABITING IN THE SURF ZONE OF SANDY COAST.

为了弄清沙质海浪带在海岸生态系统中的功能作用，作者对仙台湾沙质滩涂的生物生产过程进行了研究。结果表明：1)在仙台湾，沙质海浪带沙质滩涂常年有大量的现存量。(2)滩涂高密度分布区随潮汐移动，与低潮线的距离恒定。Mysid主要栖息地的沉积物大小中位数为2.0-2.3。3)在水温15ﾟ℃、光照0~100Lux的条件下，摄食率分别为24.8%和39.7%。4)摄食率随生长而下降，从幼体的24.6-44.2%下降到成体的8.9-13.8%。摄食后12小时，摄食标记有^&lt；14&gt；C的卤虾体内残留物质的比率为52%，摄食后24小时，摄食后24小时为38%。5)大口虾一生中至少有两次产卵的可能性，对于种群来说，他们一年有6个以上的种群。6)这些研究清楚地表明，作为沙质冲浪带生态系统中的关键物种，大久保鱼在维持沿海生物生产的基本过程中发挥着重要的作用。

In order to make clear the functional role of the sandy surf zone in a coastal ecosystem, the authors investigated the biological production process of a mysid Archaeomysis kokuboi in the Sendai bay.The summary of the results is shown below.1) In the Sendai bay, a misid A.kokuboi has a large standing crop in the sandy beaaches of surf zones all the year round. The abundance of the mysid is high especially in areas shallower than 5m in depth.2) High density distribution area of the mysid on the slope of beaches moves accompanying the tide and has a constant distance from the low tide lines. The median size of sediment of the main habitat for the mysid is 2.0-2.3. In the daytime most of the mysid are burrowing in the surface layr (0-3cm in depth) of the sand slope, and by night they are swimming in the water and feeding mainly on flagellates and copepods.3) Daily feeding rates of the mysid fed with brine shrimps for food, under the conditions of 15ﾟC in water temperature and 0-100 lux in illuminance, are 24.8% in wet weight and 39.7% in dry weight.4) Conversion rates of the food ingested to the mysid decrease with the growth ; from 24.6-44.2% in young stage to 8.9-13.8% in adult. The ratios of the amount of substance remained in the body of mysid and that ingested brine shrimp labeled with ^<14>C are 52% for 12 hours and 38% for 24 hours after feeding.5) A.kokuboi has a possibility of spawning at least more than two times throughout the life, and for the population it is recognized that they have more than 6 cohorts in one year. Cohorts bone during the warm season April-June grow fast to mature in a small size, and that bone during the cold season November-January grow slowly and spawn their eggs in spring as the larger sized adult.6) These studies clearly show that A.kokuboi plays an important role as a key species in the sandy surf zone ecosystem sustaining the basic processes in a coastal biological production.