- Original Paper
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Shoji KITAMURA, Kazumasa IKUTA, Toshio SHIKAMA, Hidefumi NAKAMURA, Yukinari SUZUKI and Arimune MUNAKATABull. Fish. Res. Agen. No.15, 1-10, 2005
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Takeyuki MATSUMOTO, Kotaro YOKAWA, Denzo INAGAKE, Keisuke MIZUNO and Yasufumi ISHIHARABull. Fish. Res. Agen. No.15, 11-25, 2005
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Goro YOSHIDABull. Fish. Res. Agen. No.15, 27-126, 2005
Technical Report
Doctoral Thesis
abstract
Original PaperTitle | Effects of catch-and-release (C&R) regulation in the Yukawa River |
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Authers | Shoji KITAMURA *1, Kazumasa IKUTA *1, Toshio SHIKAMA *1, Hidefumi NAKAMURA *1,Yukinari SUZUKI *2 and Arimune MUNAKATA *3 |
Keywords | recreational fishing, brook trout, questionnaire, catch-and-release |
Citation | Bull. Fish. Res. Agen. No.15, 1-10, 2005 |
Abstract |
In the Yukawa river, Nikko, Japan, catch-and-release (C&R) regulation has been adopted in all the fishing area since 2002. A questionnaire to the anglers was conducted throughout the fishing season (May 1 to September 30) in 2002 and 2003 to examine the effect of C&R regulation on sustaining brook trout (Salvelinus fontinalis) stocks. Compared to 2001, the numbers of angler were increased in 2002 and 2003, by 27.4% and 34.2%, respectively. Among the 3 angling methods (fly, lure, bait), the percentage of fly-fisher, who had supposedly practiced C&R even before 2002, has increased in 2002 and 2003, by 20.5% to 83.8% and by 24.8% to 88.1%, respectively. Catch rate (number of fish caught/angler-hour) in 2002 and 2003 has also increased by 0.03 to 1.05 and by 0.19 to 1.21, respectively. Brook trout populations were found to remain abundant even after the fishing season by mark-recapture method (Petersen's method). These results indicate that C&R regulation in the Yukawa river, which was accepted favorably by the anglers without serious troubles, was effective to sustain brook trout stocks.
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Received on March 4, 2005
*1 Freshwater Fisheries Research Division, National Research Institute of Fisheries Science, 2482-3 Chugushi, Nikko 321-1661, Japan
*2 The Whole Earth Publication Co. Ltd., 6-14-5 Shimbashi, Minato, Tokyo 105-0004, Japan
*3 Science Education Division, Miyagi University of Education, Aoba, Sendai, Miyagi 980-0845, Japan
Technical Report
Title | A database system for the data of small bathythermograph system SBT-500 observed during tuna longline operations |
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Authers | Takayuki MATSUMOTO *1, Kotaro YOKAWA *1, Denzo INAGAKE *2, Keisuke MIZUNO *3 and Yasufumi ISHIHARA *4 |
Keywords | database, small bathythermograph system, longline, hooking depth, oceanography |
Citation | Bull. Fish. Res. Agen. No.15, 11-25, 2005 |
Abstract |
We have developed a database system for the observation records of the small bathythermograph system SBT-500 and their related data during longline operations. The purpose of this database is to summarize and hold SBT-500 data and related data such as cruise, longline operation type, fishing gear type, biological data by species, calibration data for the sensors, and oceanographic data in order to assist analyses for studies in various fields. These data are stored in individual tables or directories in a personal computer and linked together. Using this database, analyses of 1) oceanographic conditions, 2) hooking depth, temperature and time of captured species and 3) underwater shape of longline gear can be conducted, not based on temporally and spatially limited small data sets but instead using a large amount of linked data. So far there are over 20,000 records stored, and once more data are gathered, even more reliable analyses will be possible.
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Received on March 5, 2005
*1 National Research Institute of Far Seas Fisheries, 5-7-1, Orido, Shimizu, Shizuoka, Shizuoka, 424-8633, Japan
*2 National Research Institute of Far Seas Fisheries, 2-12-4, Fukuura, Kanazawa, Yokohama, Kanagawa, 236-8648, Japan
*3 Institute of Observational Research for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15, Natsushima, Yokosuka, Kanagawa, 237-0061 , Japan
*4 Japan NUS CO., LTD., 3-9-15, Kaigan, Minato, Tokyo, 108-0022, Japan
Doctoral Thesis
Title | Phenological differentiation among populations of Sargassum horneri (Fucales, Phaeophyta) in Hiroshima Bay, Seto Inland Sea, Japan |
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Authers | Goro YOSHIDA*1 |
Keywords | Sargassum horneri, phenology, ecotypic differentiation, populations, seasonality in growth and maturation |
Citation | Bull. Fish. Res. Agen. No.15, 27-126, 2005 |
Abstract |
Sargassum horneri is one of the main components of Sargassum beds which play important roles in the coastal fisheries resource enhancement. Differentiation in seasonality, mainly in maturation season, has been known among local populations of this annual species, although ecological information about them has been rare. In the western Seto Inland Sea, spring-maturing populations, which is the common type in the western part of Japan, and autumn-maturing populations have been reported to coexist in the same sea area. The present study was conducted to investigate the ecological and physiological backgrounds of the phenological differentiation among S. horneri populations in and around Hiroshima Bay. The outline of the study is as follows; For both populations, the mortality rate was high just after the embryos attached to the substrata, and when plants began to elongate. The autumn- maturing population had to spend winter and early spring as germlings, which is generally regarded to be a stage of high mortality. However, germling mortality rate of the autumn-maturing population was low during winter and early spring, though their growth was very slow due to low temperature. Survival in this early developmental stage enables them to establish a stand in their habitat. Experimental blocks were set monthly or bimonthly to investigate seasonal algal colonization at habitats of the two S. horneri populations. At a habitat of the autumn-maturing population, colonization of S. horneri had been inhibited on the blocks placed in summer during 3 years because of the stable establishment of perennial red algae on summer blocks. Competition with these red algae was considered to affect seasonal chance of colonization and could be a selection pressure on the maturation seasonality of S. horneri. On the contrary, at a habitat of spring-maturing population, S. horneri succeeded to colonize and grow on all blocks despite of season the blocks were placed. Alternate change in physical conditions at the habitat, i.e., moderate turbulence by waves in winter and calmness in spring, was considered to be advantageous for colonization and survival of S. horneri embryos released in spring, through the reestablishment of algal succession on substrata. As a conclusion, seasonality differentiation among S. horneri populations in and around Hiroshima Bay is ecotypic, which is based on genetic difference rather than phenotypic plasticity. They have developed different physiological mechanisms related to their different seasonality. Seasonality ecotype of S. horneri in the study area could be an adaptive form to the ecological conditions at each habitat, to ensure sustainable establishment of the populations. |
Received on August 1, 2005
*1 National Research Institute of Fisheries and Environment of Inland Sea, Maruishi 2-17-5, Ohno, Saeki, Hiroshima 739-0452, Japan