DSpace Collection: 2014-07-31
http://hdl.handle.net/2115/56733
2014-07-312024-03-28T21:51:09Z北海道大学農学部に保管されていた魚類標本コレクション
http://hdl.handle.net/2115/56738
Title: 北海道大学農学部に保管されていた魚類標本コレクション
Authors: 大橋, 慎平; 永野, 優季; 加藤, 克; 河合, 俊郎; 矢部, 衞
Abstract: Approximately 3,500 fish specimens were transferred from the Faculty of Agriculture, Hokkaido University to the Fisheries Science Center, Hokkaido University Museum (HUMZ). The authors identified fishes from at least 16 orders, 57 families, 109 genera and 145 species. Although most specimens were collected around Japanese waters, several species were collected from other areas, e.g., Eleginops maclovinus (Eleginopsidae) from Chile and Luciocephalus pulcher (Osphronemidae) from India.2014-07-30T15:00:00Z大橋, 慎平永野, 優季加藤, 克河合, 俊郎矢部, 衞Approximately 3,500 fish specimens were transferred from the Faculty of Agriculture, Hokkaido University to the Fisheries Science Center, Hokkaido University Museum (HUMZ). The authors identified fishes from at least 16 orders, 57 families, 109 genera and 145 species. Although most specimens were collected around Japanese waters, several species were collected from other areas, e.g., Eleginops maclovinus (Eleginopsidae) from Chile and Luciocephalus pulcher (Osphronemidae) from India.北海道東部厚岸湖および厚岸湾における微生物食物網を構成する 微生物群の春季から初夏の変動
http://hdl.handle.net/2115/56737
Title: 北海道東部厚岸湖および厚岸湾における微生物食物網を構成する 微生物群の春季から初夏の変動
Authors: 大西, 由花; 山口, 篤; 今井, 一郎
Abstract: Temporal fluctuations of bacteria, heterotrophic nanoflagellates (HNF), autotrophic nanoflagellates (ANF) and ciliates were investigated from spring to early summer at the stations in Akkeshi-ko Estuary with large scale seagrass bed of Zostera marina and Akkeshi Bay, Eastern Hokkaodo, Japan. The ranges of bacterial density were 5.4×105-3.0×106 cells mL-1 in Akkeshi-ko Estuary (Stn. 1) and 2.3×105-1.9×106 cells mL-1 in Akkeshi Bay (Stns. 2, 3). The ranges of HNF were 3.1×102-3.3×103 cells mL-1 in the estuary and 2.2×101-1.1×103 cells mL-1 in the bay. The densities of ANF were 1.8×102-5.0×104 cells mL-1 (Stn. 1) and 2.2×101-3.6×104 cells mL-1 (Stns. 2, 3). The densities of microorganisms were higher in the coastal area than offshore. In contrast, ciliate densities were <80-9.8×103 inds. L-1 in the estuary and <80-1.1×104 inds. L-1 in the bay. Significant correlations were found between HNF and ANF, temperature and them, suggesting that major parts of ANF were mixotrophs of bacterial grazers like HNF.2014-07-30T15:00:00Z大西, 由花山口, 篤今井, 一郎Temporal fluctuations of bacteria, heterotrophic nanoflagellates (HNF), autotrophic nanoflagellates (ANF) and ciliates were investigated from spring to early summer at the stations in Akkeshi-ko Estuary with large scale seagrass bed of Zostera marina and Akkeshi Bay, Eastern Hokkaodo, Japan. The ranges of bacterial density were 5.4×105-3.0×106 cells mL-1 in Akkeshi-ko Estuary (Stn. 1) and 2.3×105-1.9×106 cells mL-1 in Akkeshi Bay (Stns. 2, 3). The ranges of HNF were 3.1×102-3.3×103 cells mL-1 in the estuary and 2.2×101-1.1×103 cells mL-1 in the bay. The densities of ANF were 1.8×102-5.0×104 cells mL-1 (Stn. 1) and 2.2×101-3.6×104 cells mL-1 (Stns. 2, 3). The densities of microorganisms were higher in the coastal area than offshore. In contrast, ciliate densities were <80-9.8×103 inds. L-1 in the estuary and <80-1.1×104 inds. L-1 in the bay. Significant correlations were found between HNF and ANF, temperature and them, suggesting that major parts of ANF were mixotrophs of bacterial grazers like HNF.北海道函館湾におけるアサリの成長
http://hdl.handle.net/2115/56736
Title: 北海道函館湾におけるアサリの成長
Authors: 田村, 亮輔; 中川, 宙飛; 五嶋, 聖治
Abstract: Shell growth of the short-necked clam Ruditapes philippinarum at Hakodate Bay, Hokkaido, Japan, was studied from February 2011 to February 2012. Monthly measurements of shell growth increment from the last ring on the shells revealed that a ring was formed annually from February to March. The Gompertz growth equation was fitted to the relationship between number of rings and shell length, and the equation, LR = 38.41exp (-exp (-0.892 (R-2.029))) was obtained, where LR is the shell length (mm) at the number of ring R. This equation shows highly depressed growth rate after 30 mm in shell length, and maximum shell length was attained about 40 mm that is smaller than those of the other localities. The estimated growth pattern was in accordance with the results of analyses of the size frequency distributions. The observed depressed growth was not explained by a shortage of food supply or seawater temperatures, but may be due to sediment character of including many cobbles and pebbles with sand which disturbs shell growth of the short-necked clam.2014-07-30T15:00:00Z田村, 亮輔中川, 宙飛五嶋, 聖治Shell growth of the short-necked clam Ruditapes philippinarum at Hakodate Bay, Hokkaido, Japan, was studied from February 2011 to February 2012. Monthly measurements of shell growth increment from the last ring on the shells revealed that a ring was formed annually from February to March. The Gompertz growth equation was fitted to the relationship between number of rings and shell length, and the equation, LR = 38.41exp (-exp (-0.892 (R-2.029))) was obtained, where LR is the shell length (mm) at the number of ring R. This equation shows highly depressed growth rate after 30 mm in shell length, and maximum shell length was attained about 40 mm that is smaller than those of the other localities. The estimated growth pattern was in accordance with the results of analyses of the size frequency distributions. The observed depressed growth was not explained by a shortage of food supply or seawater temperatures, but may be due to sediment character of including many cobbles and pebbles with sand which disturbs shell growth of the short-necked clam.Sexual size dimorphism in two endemic hermit crabs, Pagurus traversi and P. novizealandiae, in New Zealand
http://hdl.handle.net/2115/56735
Title: Sexual size dimorphism in two endemic hermit crabs, Pagurus traversi and P. novizealandiae, in New Zealand
Authors: Wada, Satoshi; Yasuda, Chiaki I.; McLay, Colin
Abstract: The evolutionary factors of sexual size dimorphism and reproductive characters in Pagurus traversi and P. novizealandiae, are discussed. Investigations and sample collection were conducted in the intertidal area around Kaikoura peninsula, southern island of New Zealand from 22 February to 23 March 2012. The number of crabs collected was 1198 P. traversi and 318 P. novizealandiae. The degree of size dimorphism ((mean male size)/(mean female size)) was 1.09 and 1.03 in P. traversi and P. novizealandiae, respectively. The fecundity relationship between clutch size and female body size (shield length, mm) in P. traversi was estimated as log10[clutch size] =1.010 + 0.794 × log10[female size3], indicating that clutch size approximately increase as an isometric relationship. All males guarded females smaller than themselves in nine precopulatory guarding pairs of P. traversi. However, difference in the mean size between the guarding males (4.79 mm) and other males (4.50 mm) was small (0.29), suggesting that large size advantage might be weak in mate acquisition compared with other species of the genus Pagurus. Weak evolutionary selection pressure acting on male body size may explain relatively small degree of sexual size dimorphism in P. traversi.2014-07-30T15:00:00ZWada, SatoshiYasuda, Chiaki I.McLay, ColinThe evolutionary factors of sexual size dimorphism and reproductive characters in Pagurus traversi and P. novizealandiae, are discussed. Investigations and sample collection were conducted in the intertidal area around Kaikoura peninsula, southern island of New Zealand from 22 February to 23 March 2012. The number of crabs collected was 1198 P. traversi and 318 P. novizealandiae. The degree of size dimorphism ((mean male size)/(mean female size)) was 1.09 and 1.03 in P. traversi and P. novizealandiae, respectively. The fecundity relationship between clutch size and female body size (shield length, mm) in P. traversi was estimated as log10[clutch size] =1.010 + 0.794 × log10[female size3], indicating that clutch size approximately increase as an isometric relationship. All males guarded females smaller than themselves in nine precopulatory guarding pairs of P. traversi. However, difference in the mean size between the guarding males (4.79 mm) and other males (4.50 mm) was small (0.29), suggesting that large size advantage might be weak in mate acquisition compared with other species of the genus Pagurus. Weak evolutionary selection pressure acting on male body size may explain relatively small degree of sexual size dimorphism in P. traversi.