Temperature-dependent stock-recruitment model for walleye pollock (Theragra chalcogramma) around northern Japan

Changes in fish year‐class strength have been attributed to year‐to‐year variability in environmental conditions and spawning stock biomass (SSB). In particular, sea temperature has been shown to be linked to fish recruitment. In the present study, I examined the relationship between sea surface temperature (SST), SSB and recruitment for two stocks of walleye pollock (Theragra chalcogramma) around northern Japan [Japanese Pacific stock (JPS) and northern Japan Sea stock (JSS)] using a temperature‐dependent stock‐recruitment model (TDSRM). The recruitment fluctuation of JPS was successfully reproduced by the TDSRM with February and April SSTs, and February SST was a better environmental predictor than April SST. In addition, the JPS recruitment was positively related to February SST and negatively to April SST. The JSS recruitment modeled by the TDSRM incorporating February SST was also consistent with the observation, whereas the relationship between recruitment and February SST was negative, that is the opposite trend to JPS. These findings suggest that SST in February is important as a predictor of recruitment for both stocks, and that higher and lower SSTs in February act favorably on the recruitment of JPS and JSS respectively. Furthermore, Ricker‐type TDSRM was not selected for either of the stocks, suggesting that the strong density‐dependent effect as in the Ricker model does not exist for JPS and JSS. I formulate hypotheses to explain the links between SST and recruitment, and note that these relationships should be considered in any future attempts to understand the recruitment dynamics of JPS and JSS.     

中日水产品流通体系的比较与启示

日本是世界上最大的水产品消费国和进口国，其水产品流通体系具有很强的代表性、借鉴性，文章通过分析日本水产品流通渠道的形式和特征，结合中国现阶段水产品流通结构的比较，提出中国构建有效水产品流通渠道的建议。     

Distribution and migration of Japanese common squid, Todarodes pacificus, in the southwestern part of the East (Japan) Sea

Data on squid catches of Korean and Japan, water temperatures at depth of 100 m, and night-visible images of fishing boats collected in the East (Japan) Sea from 1970 to 1999 were analyzed to examine the distribution and migration of the Japanese common squid, Todarodes pacificus, in the southwestern part of the East (Japan) Sea. The main fishing grounds detected from squid catch in each grid (0.5° latitude × 0.5° longitude) by Korean squid fishery and night-visible images provided by the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) were situated in the southwestern part of the East (Japan) Sea. The distribution and migration route was illustrated from squid catch in each grid and DMSP OLS image. In years of high catches, the fishing grounds were situated mainly between Ulleung Island and the eastern coastal waters of Korea, while in years of low catches they were situated between Ulleung Island and the Yamato Bank in the central East (Japan) Sea. The center of fishing activity began moving northward from around the Korea/Tsushima strait to the northern boundary of the Tsushima Warm Current in March, reaching into the Yamato Bank in September, and then returning to the strait by February. The northward and southward migration routes differed; the northward migration route occurred closer to the mainland coast of Korea than the southward migration route did. This work suggests T. pacificus begin their northward migration almost 2 months earlier than previously suggested.     

日本旋耕机技术特点及操作使用要点

旋耕机作为一种耕整地机械,一次作业可完成耕耘、碎土、整地等多项作业,具有相当高的效率.而且其使用、操作、调整均很简单.因此从1975年开始,旋耕机作为农业机械化的支柱在日本被广泛使用,支撑着日本的农业生产.发展至今,旋耕机已趋于多功能化,不仅仅是耕耘,只要在旋耕机上安装不同的附属设施,就可以进行不同的作业,大大扩展了其作业范围.目前在水田、旱地等均广泛应用着旋耕机.     

桂林抗战文化与中国现代文学

抗战时期，桂林的抗战文化运动蓬勃发展，被誉为“文化城”。荟萃桂林的现代作家在中国共产党领导和文协桂林分会的推动下，众志成城，使得桂林的抗战文学创作空前繁荣，创作了一大批思想和艺术较高、影响较大的优秀文学作品，大大地丰富了我国现代文学宝库，在中国新文学史上写下了光辉的一页。     

日本农产品批发市场考察报告

详细介绍了东京大田农产品批发市场和名古屋批发市场在果菜、水产、花卉方面的交易情况，并对日本批发市场的设置程序和交易原则进行了简要阐述，最后提出发展中国批发市场的几点建议。     

日本的营养液栽培现状及其新技术

该文从营养液栽培的发展规模、投资费用、营养液栽培方式等方面介绍了日本营养液栽培的现状、存在的问题及发展方向。在营养液管理方面，已发现单纯依靠检测电导率EC值控制营养液浓度的弊端，提出应针对各种离子的营养液浓度进行管理；各种废液的处理方法和营养液循环利用中去除病原菌和生长阻害物质的方法。分析了各种方法的利弊。最后该文详细介绍了日本营养液栽培的新技术——移动栽培和营养液土耕的基本原理，主要方法和效果。     

Precipitation chemistry in Japan 1989–1993

Precipitation chemistry in Japan was discussed on a wet-only sample database obtained in a nationwide survey from April 1989 to March 1993. Wet-only samples were collected at 29 stations over Japan on a biweekly basis. Commonly determined chemical parameters were measured in laboratories. The volume-weighted annual mean pH at each site ranged from 4.50 to 5.83 with a mean of 4.76. Concentration ranges and means (parenthesized) on an equivalent basis for major ions were as follows: nss-SO₄ ^2–; 5.2–58.9 (38.6), NO₃ ^–; 1.8–25.0 (14.1), NH₄ ⁺; 0.55–29.8 (18.3), nss-Ca²⁺; 2.0–34.5(14.2), Na⁺; 6.4–275.3 (49.1), Cl^–; 13.7–322.4 (63.5) eq L^–1. Acid-base relationships for Phase-II records were quantitatively discussed in terms of three measures: pH, fractional acidity, and our proposed pA_i.     

Establishing an acid deposition monitoring network in East Asia

Acid deposition is widely recognized as one of the most serious international atmospheric pollution problems. East Asian countries are currently experiencing acid deposition and have only recently begun expanding domestic research and monitoring activities. However, acid deposition is not only a domestic but also a transboundary problem. In addressing the transboundary aspect, cooperative and collaborative action will be essential. The Environment Agency of Japan is advocating the need to establish an acid deposition monitoring network in East Asia. Therefore, it is sponsoring three Expert Meetings on Acid Precipitation Monitoring Network in East Asia between 1993 and 1995. The meetings are attended by both scientific researchers and government officials from numerous East Asian countries. At the administrative and scientific discussions of the first two meetings a consensus on the desirability of establishing a monitoring network in East Asia was obtained and a preliminary technical guideline manual for monitoring acid deposition was adopted. By the end of the third meeting it is hoped that a basic consensus can be reached on a framework for an East Asian acid deposition monitoring network. It is essential to establish such a network in order to evaluate the present state of acid deposition in the region and to reach a common scientific understanding on the acid deposition problem. This is a vital step toward promoting international cooperation on the issue.     

日本近50年来土壤侵蚀及水土保持研究评述

系统地评价了日本土壤侵蚀及水土保持研究工作，介绍了日本土壤侵蚀及水土保持研究的发展历史和现状，以及主要开展这方面研究的大学、研究机构和主要的研究代表者及其成果。对日本土壤侵蚀及水土保持研究的特点以及所取得的主要成果进行了客观地评价。