This study examined the possibility of the LED panels as a fishing lamp system in the coastal squid jigging fishery for swordtip squid and Japanese common squid. Fishing trials were carried out using coastal squid jigging boats (6.6-7.3 t) equipped with LED panels. The catch amounts of squid jigging boats with LED panels (experimental boats) were compared with the catch of a control boat equipped with conventional lamps, which simultaneously operated in the same water. The catch amounts of the experimental boats were less than that of the control boat. Besides, catch amounts were expressed as functions of light source, lunar phase, tide, presence of dolphin in the generalized linear modeling analysis. Catch performance of the light source for swordtip squid and Japanese common squid were different, and catching swordtip squid was presumed to require less light source power. Hence, Squid jigging fishery for swordtip squid was easier it was to introduce the LED panels.

　The present study examined the proportion of the terminal molt and carapace width (CW) distribution of male snow crab Chionoecetes opilio in southern Tohoku, Japan. Samples were collected from landings caught by otter trawls operated off Miyagi, Fukushima and Ibaraki Prefectures from 2007 to 2010. The proportion of the terminal molt in males of 80-119 mm CW was higher in the area off Fukushima than that off Ibaraki. The CW of crabs off Miyagi and Fukushima was significantly smaller than that off Ibaraki. These results suggest the geographic variation in the size-related terminal-molt proportion and carapace width of the male snow crab off the Pacific coast of southern Tohoku, Japan.

　Using the mitochondrial DNA control region sequences of 549 bp for 618 Pacific herring from 16 spatiotemporal samples collected at nine spawning sites in the Hokkaido and Tohoku areas of Japan during the spawning period between 2003 and 2014, we estimated the contemporary population structure and demographic history of the Japanese herring. Neighbor-joining unrooted phylogenetic trees based on the empirical Bayes pairwise F_ST values showed three large clusters consisting of six local samples in Hokkaido, Lake Obuchi-numa, and Miyako Bay/Matsushima Bay in Tohoku. Hokkaido samples had higher genetic diversity than Honshu samples. The haplotype frequency of Miyako Bay after the Great Tohoku earthquake was substantially different to that before the earthquake, but similar to that of Lake Obuchi-numa. Our demographic analyses inferred that the effective population size (N_e) has expanded since at least ～600 kyr ago in Hokkaido but is stable in Honshu, but a rapid and simultaneous decrease in N_e has occurred since ～20 kyr ago in Japanese herring, corresponding to the warming after the Last Glacial Maximum.

　Age and growth of red tilefish Branchiostegus japonicus caught from June to December, 2012 in western Wakasa Bay, Japan, were investigated based on otolith analyses using the cross-section and surface methods. Assuming annual formation of ring marks and a hatching date of September 1, which was inferred based on observed monthly change in the proportion of mature females (GSI≥2.5), ages were assigned to individuals according to the number of ring marks in the sectioned otoliths. Since there were almost no one- or two-year-old fish specimens sampled, back-calculated length data of these fish were complemented using otoliths of ring groups 1-3 by the surface method. Briefly, the first and second ring radii of each specimen were substituted into relational expressions between otolith radius and standard length of females and males. Length-at-age data were fitted to the von Bertalanffy growth equations by a non-linear least squares method. The equations were estimated as follows: Lt=276(1−exp^{−0.490(t−0.215)}) for females and Lt=389(1−exp^{−0.320(t−0.0483)}) for males, where Lt is the standard length (mm) at age t. The maximum ages observed were 18 and 14 years for females and males, respectively.

　The color variation and the maturation process of ovaries in mature female Lucensosergia lucens (Sergestidae) were studied by qualitative classification, digital image analysis, and histological observation. The classified color pattern in ovaries corresponded to the most developed oocyte stage. There were significant differences in L^∗, a^∗, and b^∗ values between the two groups of mature females with/without the oocytes of the later development stages. Multivariate analysis also described the color variations in those two groups. This study showed that ovary color variation was related to the development of the oocytes. The relationship between three qualitative ovary color patterns and the most developed oocyte stages was as follows: light blue-gray ovaries contained oocytes at primary-tertiary yolk granule stages (YGSs), greenish blue-gray ovaries contained oocytes at pre-maturation and maturation stages (PMS/MS), and dark blue-gray ovaries contained oocytes at YGSs or PMS/MS, both of which were almost the same in number.

　Edible hard clam Meretrix lamarckii is an important fishery resource along the Kashimanada coast, Ibaraki Prefecture, Japan. The aim of this study was to establish a method of determining age by verifying whether two types of growth patterns, growth lines seen in shell cross-section and “rings” visible on shell surface, are formed on an annual basis or not. To this end, we examined the shells obtained from a mark-recapture experiment that enabled us to specify growth periods after a release. Shell cross-sections were prepared using a hand-held grinder equipped with a thin diamond grinding disc and polished. High-resolution pictures of the cross-section surface were taken using a commercial photo scanner. The number of growth lines in the cross-sections was consistent with the number of winters the shellfish had experienced after release, suggesting that the growth lines were formed in winter on an annual basis. On the other hand, the “rings” on the shell surface rarely matched the expected growth periods. This study shows that the number of growth lines recognized in the shell cross-section is a more reliable method of determining the age of the hard clam.

　Volatile flavor compounds (VOC) in niboshi, boiled and dried anchovy Engraulis japonicus, and its extracts were analyzed by SPME-GC/MS to investigate the effects of lipid oxidation during the drying process on the odor of niboshi and the soup stock extracted from it. The amount of VOC was higher in niboshi when lipid levels of the raw material, anchovy, were higher and it also increased with drying time of boiled anchovy. The VOC and thiobarbituric acid levels in the soup stocks extracted from niboshi containing high levels of VOC were high. It can thus be concluded that niboshi from fatty anchovy contains high levels of secondary products having an unpleasant odor which is generated from lipids during the drying process and the secondary products will adversely affect the flavor of soup stock. These results suggest that omitting the drying process could be effective for reducing the odor of fatty anchovy extracts.

 North Pacific krill Euphausia pacifica has very low commercial value in Japan due to its small size and high autolytic activity. To utilize the krill as a raw material of gel products, a new method to recover the krill protein by salt water treatment was investigated. The krill was homogenized with NaClaq (final conc. 4%) and then diluted to 10 times (v/v) to obtain precipitate as recovered protein. Both Ca-ATPase and Mg-ATPase activities of the recovered protein were high. Thermal gels from the recovered krill protein were obtained when heated at 80-90℃, whereas intense proteolysis was observed in the SDS-PAGE pattern. These results suggest that the new method to recover North Pacific krill protein by salt water treatment is useful, and that the krill protein has gel-forming ability.