Abstract In order to understand the diet of Laysan Albatross Phoebastria immutabilis and Black-footed Albatross P. nigripes in western North Pacific waters, we investigated isotopic differences between species, sexes and breeding stages. We measured carbon and nitrogen isotope ratios in the muscles and livers of albatrosses (caught during Japanese pelagic longline fishing) and in their potential prey. Both δ 13C and δ15N of Black-footed Albatross were higher than those of Laysan Albatross. Delta13C of both species differed seasonally and δ13C was lower during the incubation period than during the chick-provisioning and non-breeding periods. The δ 13C and δ15N levels of males did not differ from those of females in either species. Our results suggest that Black-footed Albatross forages on higher isotope prey items and/or Laysan Albatross forages on lower isotope prey items other than squid and fish and that δ13C varies in response to seasonal variation in prey availability. This implies that Black-footed Albatross forages more on discard from the fishing industry than does Laysan Albatross; this in turn may be related to the areas of operation sea area of the longline fisheries in the western North Pacific. In conclusion, it is important for conservation of these two albatross species to monitor their diets and foraging areas and to identify the species-specific high-risk areas where albatross bycatch is most likely.

The stomach contents (food and ingested plastics) of Laysan Albatross Phoebastria immutabilis and Black-footed Albatross P. nigripes were examined by necropsy analysis of birds caught as bycatch in the pelagic longline fisheries in the Western North Pacific. The contents were classified separately for the proventriculus and gizzard. Undigested fish and cephalopods were found in the proventriculus, while hard objects such as cephalopod beaks, plastics, and pebbles were found in the gizzard. This indicates that the retention time of soft tissues in fish or cephalopods differs from that for hard objects. The main prey of both albatrosses consisted of mesopelagic cephalopods such as Cranchiidae, Gonatidae, Histioteuthidae, and Onychoteuthidae species. Laysan Albatrosses also foraged on small teleosts (Japanese Anchovy Engraulis japonicus and some Myctophidae fishes) as major prey items. The estimated dorsal mantle length of cephalopods preyed upon by the albatrosses was below 200 mm, which was smaller than the mature sizes of those cephalopods and the size class mainly preyed upon by cetaceans. This implies that the albatrosses may forage on immature cephalopods floating in the surface layer. Ingested plastics were found in 71.8% of Laysan and 31.8% of Black-footed Albatrosses and plastic fragments were the most abundant.

Monitoring and managing fisheries bycatch is increasingly recognized as a critical component of robust fisheries management frameworks. This review, addressing this subject, begins by defining bycatch and analyzing the reasons it happens, from accidental to intentional discarding. It identifies the most common species composing bycatch of the main tuna fisheries using purse seine and longline gear. Considerations of options available to estimate bycatch, their potential biases and uncertainties, and ways to address these issues are discussed. The formulas used to estimate bycatch also point to the options to reduce them, lowering bycatch per unit of effort or lowering effort itself. It shows that a mean can be reduced by reducing all its component figures, or by eliminating the high values at the extreme of the distribution (i.e., where a small proportion of events causes a large proportion of the problem), a common issue in bycatch. A generic strategy is described that can be applied to all gears and fisheries, and it is then described for the fisheries of interest, showing examples of its application. These cover many mitigation actions based on gear and operational changes. Management options aiming at reducing bycatch are also mentioned. A detailed description of the ways the strategy has been implemented for purse seiners and longliners is provided. Finally, market strategies, education and awareness of stakeholders, mainly fishers, and some potential future developments are briefly described.

1. The effectiveness of tori-lines combined with double-weighted branch lines in reducing seabird bycatch was evaluated in a pelagic longline fishery. 2. Seabird bait attack behaviour, bycatch number, and sinking rate of baited hooks were examined on double-weighted and unweighted branch lines deployed on the same longline with a single tori-line. Comparisons were conducted from July to October in 2011 during two cruises on a chartered longline vessel in the eastern South Pacific Ocean outside the Chilean and Peruvian exclusive economic zones. 3. Cape petrels (Daption capense), white-chinned petrels (Procellaria aequinoctialis) and Westland petrels (Procellaria westlandica) were abundant during line setting. There were 275 primary bait-taking attacks by these species, but there were only eight primary attacks by albatrosses. Nevertheless, six albatrosses and six diving seabirds were incidentally caught as bycatch. Of the primary attacks by Cape petrels, white-chinned petrels and Westland petrels, 153 led to secondary attacks. These results suggest that off Chile and Peru there is frequent secondary bycatch of albatrosses as a result of their stealing bait from Cape petrels and diving seabirds. 4. Best-fit models for the number of primary attacks and of bycatch included the weighted branch line; the use of weighted branch lines resulted in a lower number of primary attacks. Hooks on unweighted branch lines did not reach any of the benchmark depths (3, 5, and 10m) within the aerial extent of the tori-lines (the tori-line remaining above the water surface), hooks on weighted branch lines reached 5m depth within the aerial extent. These results suggest that, for the pelagic longline fishery off Chile and Peru, combining double-weighted branch lines and tori-lines reduces the bycatch more effectively than tori-lines with unweighted branch lines. Copyright (c) 2014 John Wiley & Sons, Ltd.

Longline surveys have been conducted in the Northwest Pacific Ocean from 2000 to 2014 using chartered commercial longline vessels. Each year, two cruises were conducted offshore of northeastern Japan from mid-April to mid-June. For each longline set during the surveys, onboard scientists collected detailed biological information about the species caught, such as the size and sex, and recorded the catch numbers for all species. Blue shark (Prionace glauca) and shortfin mako (Isurus oxyrinchus) have eurythermal distributions, but the application of a generalized additive model (GAM) showed that the sea surface temperatures (SSTs) at catch sites positive for shortfin mako were warmer than those for blue shark. On the basis of the GAM, the probabilities of occurrence of both sharks differed by size category: small sharks had a narrower SST range than that of large sharks. Most catches of both sharks were juveniles, and the nominal catch rate of blue shark was more than 10 times that of shortfin mako. The standardized catch per unit effort (CPUE) for both species was calculated using a generalized linear model (GLM) with negative binomial errors, or a delta-lognormal GLM. The standardized CPUE for blue shark in the second quarter of the year peaked in the mid-2000s and then decreased, but it has been increasing since 2012. The CPUE for shortfin mako in the second quarter generally increased, with fluctuations.

The new seabird mitigation regulation was enforced in July 2014 in the area south of 25S in IOTC convention area. It demand for fisheries to adopt two of three mitigation measures of tori-line, night setting and blanch line weighting which have high effectiveness for mitigation of seabird bycatch (Melvin et al. 2014, Sato et al. 2014). In this document, Japanese seabird by catch data in the south Indian Ocean (south of 25S) collected by on-board observers in the period before and after the introduction of the new regulation were reviewed, to explore the possibility to evaluate the effectiveness of the new mitigation measures. It seems that the distribution of the observer data collected form almost main fishing areas of Japanese longliners in the period analyzed. The observer data indicated that many Japanese tuna longline vessel (71-94%) had already adopted the combination use of weighting blanch line and Tori line or night setting and Tori line before the introduction of regulation (2012 2013). This would be mostly due to the fact that bait loss by seabirds is one of serious concern of Japanese fishers but also suggest their positive attitude toward seabird conservation. The amount of data seemed insufficient as data after the introduction of the new regulation was only one year, analytical method supposed to be rather preliminary. However, the good efficiency of the regulation with using fisheries data, further collection of data appeared to be necessary for the stochastic evaluation of the effect of new mitigation measure, such as considering the effect of the interaction of each mitigation, target species. Also, the detail situation when the mitigation measures were used would be needed to investigate in the future. Introduction Recently, new seabird mitigation regulation was introduced in ICCAT, IOTC and WCPFC conventional area (ICCAT; Rec11-09 started from July 2013,IOTC; Res 12/06 started from July 2014, WCPFC; Conservation Measure 2012-07 started from July 2014), and the commission of these tuna RFMOs tasked their scientific committee to evaluate its effectiveness of the regulation needs to be tested. It demand for fisheries to adopt two of three mitigation measures of tori-line, night setting and blanch line weighting which have high effectiveness for mitigation of seabird bycatch (Melvin et al. 2014, Sato et al. 2014). In this document, Japanese seabird by catch data in the south Indian Ocean (south of 25S) collected by on-board observers in the period before and after the introduction of the new regulation were reviewed, to explore the possibility to evaluate the effectiveness of the new mitigation measures. It seems that the distribution of the observer data collected form almost main fishing areas of Japanese longliners in the period analyzed. IOTC–2015–WPEB11–37 Rev_1

The North Pacific Transition Zone (NPTZ) is one of the most productive offshore regions. To identify important habitats for pelagic top predators within this region, we investigated the at-sea distributions of black-footed (Phoebastria nigripes) and Laysan albatrosses (P. immutabilis) by vessel-based surveys during their non-breeding season (July and October in 2010 and September and October in 2011). We developed statistical models using satellite-based oceanographic data at spatial scales of 4, 20 and 80 km to explain their densities. For both species, sea surface temperatures (SST) and distance to the Emperor Seamounts emerged as important factors in the better-fitting models at all spatial scales. In addition, black-footed albatrosses were widely distributed in the NPTZ (SST 17.7–27.4 °C), whereas Laysan albatrosses favoured northern and colder waters (13.6–25.4 °C). Our results also indicated that the Emperor Seamounts, where trawling and longline fishing occur, were an important habitat for both species in the NPTZ. Therefore, careful attention should be paid to interactions between fisheries and albatross species in this region.

Fast growth plays an important role in survival processes during the early life stages of both field-captured and hatchery-reared Pacific bluefin tuna Thunnus orientalis. Marked growth variations in hatchery-reared tuna larvae are frequently observed even for the same age and within the same rearing tank after the onset of the piscivory. We hypothesized that these small growth variations in the growth of tuna larvae at the onset of piscivory lead subsequently to large growth variations and tested the hypothesis using three size groups (large, intermediate and small) of hatchery-reared fish by nitrogen stable isotope and otolith analyses. Stable isotope analysis revealed that the large group rapidly utilized prey fish larvae, but the smaller groups depended more on rotifers as the main prey item relative to the large group. The otolith radius from the core to the increment corresponding to the first feeding on yolk-sac larvae was compared among the three size groups. The results revealed that the large group had larger otolith radii than the small and intermediate groups. Our findings suggest that small growth variations apparent during the early larval stage of tuna could induce further large growth variations in the late-larval and juvenile stages through differences in the initial ability to utilize piscivory.

In mass culture of Pacific bluefin tuna Thunnus orientalis, a marked growth variation is observed after they start feeding at 6-7mm in body length (BL) on yolk-sac larvae of other species, and the growth variation in tuna larvae is a factor leading to the prevalence of cannibalism. To examine the relationship between prey utilization and growth variation, nitrogen stable isotope ratios (N-15) of individual larvae were analysed. A prey switch experiment was conducted under two different feeding regimes: a group fed rotifers (rotifer fed group), and a group fed yolk-sac larvae of spangled emperor, Lethrinus nebulosus (fish fed group) from 15days after hatching (6.87mm BL). The fish fed group showed significantly higher growth than the rotifer fed group. Changes in the N-15 of the fish fed group were expressed as an exponential model and showed different patterns from those of the rotifer fed group. The N-15 of fast-growing tuna larvae collected in an actual mass culture tank after the feeding of yolk-sac larvae was significantly higher than those of the slow-growing larvae, indicating that slow glowing larvae depended largely on rotifers rather than the yolk-sac larvae.

To examine the effectiveness of the paired tori lines (PT) for reducing seabird bycatch in pelagic longline fisheries, bait attack behaviors during PT deployment was compared with that during single tori line (ST) deployment. Detailed observations of seabird species abundance and attacks on baits were conducted from a longliner operating in the western North Pacific from December 2010 to January 2011. Line settings alternated between ST and PT deployments. About 90% of the seabirds attending the vessel were Laysan albatrosses (Phoebastria immutabilis), and most attacks were by this species. Attacks occurred across broad areas from 25 to 200 m of the stern during ST deployments, whereas PT deployment resulted in few attacks within 75 m of the stern. The number of secondary attacks (birds charging for the bait brought to the surface by the bird making the primary attack) was significantly lower during PT than during ST deployment. These results suggest that PT performed better than ST in reducing bait attacks, and consequently seabird mortality. (C) 2012 Elsevier B.V. All rights reserved.

Rice has developed several morphological and physiological strategies to adapt to phosphate starvation in the soil. In order to elucidate the molecular basis of response to phosphate starvation, we performed mRNA sequencing of 4 rice cultivars with variation in growth response to Pi starvation as indicated by the shoot/root dry weight ratio. Approximately 254 million sequence reads were mapped onto the IRGSP-1.0 reference rice genome sequence and an average of about 5,000 transcripts from each cultivar were found to be responsive under phosphate starvation. Comparative analysis of the RNA-Seq profiles of the 4 cultivars revealed similarities as well as distinct differences in expression of these responsive transcripts. We elucidated a set of core responsive transcripts including annotated and unannotated transcripts commonly expressed in the 4 cultivars but with different levels of expression. De novo assembly of unmapped reads to the Nipponbare genome generated a set of sequence contigs representing potential new transcripts that may be involved in tolerance to phosphate starvation. This study can be used for identification of genes and gene networks associated with environmental stress and the development of novel strategies for improving tolerance to phosphate starvation in rice and other cereal crops.

Epicuticular wax (bloom) plays important roles in protecting the tissues of sorghum ( Sorghum bicolor (L.) Moench) plants from abiotic stresses. However, reducing wax content provides resistance to greenbug and sheath blight—a useful trait in agricultural crops. We generated a sorghum bloomless ( bm ) mutant by gamma irradiation. One bm population segregated for individuals with and without epicuticular wax at a frequency of 72:22, suggesting that the bm mutation was under the control of a single recessive nuclear gene. Genes differentially expressed in the wild-type and the bm mutant were identified by RNA-seq technology. Of the 31 downregulated genes, Sb06g023280 was the most differentially expressed and was similar to WBC11 , which encodes an ABC transporter responsible for wax secretion in Arabidopsis. An inversion of about 1.4 Mb was present in the region upstream of the Sb06g023280 gene in the bm mutant; it is likely that this inversion changed the promoter sequence of the Sb06g023280 gene. Using genomic PCR, we confirmed that six independent F 2 bm mutant-phenotype plants carried the same inversion. Therefore, we concluded that the inversion involving the Sb06g023280 gene inhibited wax secretion in the bloomless sorghum.

Soybean [Glycine max (L) Merrill] is one of the most important leguminous crops and ranks fourth after to rice, wheat and maize in terms of world crop production. Soybean contains abundant protein and oil, which makes it a major source of nutritious food, livestock feed and industrial products. In Japan, soybean is also an important source of traditional staples such as tofu, natto, miso and soy sauce. The soybean genome was determined in 2010. With its enormous size, physical mapping and genome sequencing are the most effective approaches towards understanding the structure and function of the soybean genome. We constructed bacterial artificial chromosome (BAC) libraries from the Japanese soybean cultivar, Enrei. The end-sequences of approximately 100,000 BAC clones were analyzed and used for construction of a BAC-based physical map of the genome. BLAST analysis between Enrei BAC-end sequences and the Williams82 genome was carried out to increase the saturation of the map. This physical map will be used to characterize the genome structure of Japanese soybean cultivars, to develop methods for the isolation of agronomically important genes and to facilitate comparative soybean genome research. The current status of physical mapping of the soybean genome and construction of database are presented.

Similarity of gene expression across a wide range of biological conditions can be efficiently used in characterization of gene function. We have constructed a rice gene coexpression database, RiceFREND (http://ricefrend.dna.affrc.go.jp/), to identify gene modules with similar expression profiles and provide a platform for more accurate prediction of gene functions. Coexpression analysis of 27 201 genes was performed against 815 microarray data derived from expression profiling of various organs and tissues at different developmental stages, mature organs throughout the growth from transplanting until harvesting in the field and plant hormone treatment conditions, using a single microarray platform. The database is provided with two search options, namely, 'single guide gene search' and 'multiple guide gene search' to efficiently retrieve information on coexpressed genes. A user-friendly web interface facilitates visualization and interpretation of gene coexpression networks in HyperTree, Cytoscape Web and Graphviz formats. In addition, analysis tools for identification of enriched Gene Ontology terms and cis-elements provide clue for better prediction of biological functions associated with the coexpressed genes. These features allow users to clarify gene functions and gene regulatory networks that could lead to a more thorough understanding of many complex agronomic traits.

Use of circle hooks is regarded as an effective method to reduce incidental mortality of non-targeted species (e.g., sea turtles) in longline fisheries. Currently, various types of circle hook are produced and distributed commercially. Many researchers worldwide have examined the effect of circle hooks on hooking location, catch rate, and/or mortality for various species, using different types of hooks of various shapes and sizes. However, much work remains to be done to quantify the effects of circle hooks on catch and mortality rates of both target and non-target species. Consideration of practical utility is also important to facilitate wider application of circle hooks in commercial fisheries. Here we focus on some elements of circle hook morphology, i.e., hook width, offset, and incurved point angle, and discuss their potential effects on hook function (i.e., hooking location, catch rate) and practical utility. Further empirical circle hook studies are required to verify the effects discussed here.

Carbon and nitrogen stable-isotope ratios were measured in the egg yolks of four species of seabirds in Teuri Island and Rishiri Island, Japan. Delta N-15 of the yolks of Rhinoceros Auklets Cerorhinca monocerata (11.2-12.3 parts per thousand) and Black-tailed Gulls Larus crassirostris (11.3-12.5 parts per thousand) were lower than those of Slaty-backed Gulls Larus schistisagus (13.4-14.2%0) and Japanese Cormorants Phalacrocorax capillatus (14.0-16.2 parts per thousand); suggesting that the former two species foraged mainly on low trophic level small fishes and sometimes on krill, while the latter two species fed on higher trophic level prey and larger fishes.