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Larvae of Auxis rochei and Auxis thazard are commonly found in tropical to temperate waters around the world; however, their identification is difficult due to their similar morphological characteristics. In order to determine the morphological differences between larvae of these two species, we identified larvae of 192 A. rochei and 119 A. thazard using species-specific genetic markers and compared their melanophore patterns at each growth stage. The larvae of both species ranged from 3.5 to 6.9 mm in length and were identified with high accuracy based on the patterns of melanophore distribution at the snout tip and on the caudal peduncle. Using these morphological characteristics, we developed an identification key for the larvae of these two Auxis species based on their growth stage.

Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size. Resumo Kajikia audax, Thunnus albacares, Katsuwonus pelamis e Auxis spp. ocupam posições tróficas intermedias e/ou elevadas nas cadeias alimentares. Estas espécies representam um importante recurso pesqueiro no Ecuador. Apesar da sua importância económica e ecológica, estudos nestas espécies pelágicas no Ecuador são raras. Este estudo usa isótopos estáveis para avaliar o seu nível trófico de modo a determinar a contribuição das suas presas para os tecidos destes predadores. Dados dos isótopos foram usados para testar a hipótese de que estas espécies de peixes pelágicos possuem valores mais elevados de δ15N do que daqueles das presas consumidas, e que não existe uma sobreposição entre os valores de δ13C e δ15N. Resultados mostram que valores mais elevados de δ15N para K. audax, seguidos por T. albacares, Auxis spp. e K. pelamis, indicam que a posição mais elevada na cadeia alimentar é ocupada por K. audax. Elipses Bayesianas de isótopos estáveis demonstram que, a uma escala de longo-termo, estas espécies de peixes não competem pelos recursos. Adicionalmente, os valores de δ15N são diferentes entre espécies de peixe estudadas e estes valores decrescem com a diminuição do tamanho do predador.

Auxis rochei (Risso, 1810). Bullet Tuna. To 55 cm (21.6 in) TL (Nakamura in Masuda et al. 1984). Circumglobal; western Pacific Ocean north to southern Kuril Islands (Parin 2003); between Halfmoon Bay and San Francisco, central California (Personal communication: California Academy of Sciences Fish Collection, San Francisco, California) to northern Chile (Peque��o 1997), including Gulf of California (Collette in Fischer et al. 1995), and Islas Gal��pagos (Grove and Lavenberg 1997). Neritic and oceanic epipelagic; depth: surface to 200 m (656 ft) (Robertson and Allen 2002). The eastern Pacific form is recognized as the subspecies Auxis rochei eudorax Collette and Aadland 1996 (Collette 2003)., Published as part of Love, Milton S., Bizzarro, Joseph J., Cornthwaite, Maria, Frable, Benjamin W. & Maslenikov, Katherine P., 2021, Checklist of marine and estuarine fishes from the Alaska-Yukon Border, Beaufort Sea, to Cabo San Lucas, Mexico, pp. 1-285 in Zootaxa 5053 (1) on page 211, DOI: 10.11646/zootaxa.5053.1.1, http://zenodo.org/record/5578008, {"references":["Masuda, H., Amaoka, K., Araga, C., Uyeno, T. & Yoshino, T. (Eds). (1984) The Fishes of the Japanese Archipelago. Tokai University Press, Tokyo.","Parin, N. V. (2003) An annotated catalogue of fish-like vertebrates and fishes of the seas of Russia and adjacent countries: Part 3. Orders Perciformes (excluding suborders Gobioidei, Zoarcoidei and Stichaeoidei) and Tetraodontiformes. Journal of Ichthyology, 43, S 1 - S 40.","Pequeno R., G. (1997) Peces de Chile. Lista sistematica revisada y comentada: addendum. Revista de Biologia Marina y Oceanografia, 32, 77 - 94.","Fischer, W., Krupp, F., Schneider, W., Sommer, C., Carpenter, K. E. & Niem, V. H. (1995) Guia FAO para la identificacion para los fines de la pesca. Pacifico centro-oriental. Volume II, Vertebrados, Parte 1. Volume III, Vertebrados, Parte 2. FAO, Rome.","Grove, J. S. & Lavenberg, R. J. (1997) The Fishes of the Galapagos Islands. Stanford University Press, Stanford.","Robertson, D. R. & Allen, G. R. (2002) Shorefishes of the tropical eastern Pacific: an information system. CD-ROM. Smithsonian Tropical Research Institute, Balboa, Panama.","Collette, B. B. & Aadland, C. R. (1996) Revision of the frigate tunas (Scombridae, Auxis), with descriptions of two new subspecies from the eastern Pacific. Fishery Bulletin, 94, 423 - 441.","Collette, B. B. (2003) Family Scombridae Rafinesque 1815. Mackerels, tunas, and bonitos. California Academy of Sciences Annotated Checklists of Fishes, No. 19."]}

Auxis thazard (Lacep��de, 1800). Frigate Tuna. To 61 cm (24 in) TL (Miller and Lea 1972). Circumglobal; Huntington Beach (Personal communication: Los Angeles County Museum of Natural History Fish Collection, Los Angeles, California), and Santa Catalina Island, southern California to Chile (Peque��o 1989), including Gulf of California (Robertson and Allen 2015) and Islas Gal��pagos (Miller and Lea 1972). The record of this species from the southern Kuril Islands in Savinykh (1998) appears to be in error and was changed to Auxis rochei in Parin (2003). Neritic and oceanic epipelagic; depth: surface to 200 m (656 ft) (Robertson and Allen 2002). The eastern Pacific form is recognized as the subspecies Auxis thazard brachydorax Collette and Aadland 1996 (Collette 2003)., Published as part of Love, Milton S., Bizzarro, Joseph J., Cornthwaite, Maria, Frable, Benjamin W. & Maslenikov, Katherine P., 2021, Checklist of marine and estuarine fishes from the Alaska-Yukon Border, Beaufort Sea, to Cabo San Lucas, Mexico, pp. 1-285 in Zootaxa 5053 (1) on page 211, DOI: 10.11646/zootaxa.5053.1.1, http://zenodo.org/record/5578008, {"references":["Miller, D. J. & Lea, R. N. (1972) Guide to the coastal marine fishes of California. California Department of Fish and Game Fish Bulletin, 157.","Pequeno R., G. (1989) Peces de Chile lista sistematica revisada y comentada. Revista de Biologia Marina y Oceanografia, 24, 1 - 132.","Robertson, D. R. and Allen, G. R. (2015) Shorefishes of the Tropical Eastern Pacific: an Information System. Version 2.0 (2008). Smithsonian Tropical Research Institute, Balboa. http: // biogeodb. stri. si. edu / sftep / en / pages","Savinykh, V. F. (1998) Nekton composition of near-surface waters of the subarctic front zone in the northwest part of the Pacific Ocean according to the data of drift-net catches. Journal of Ichthyology, 38, 18 - 27.","Parin, N. V. (2003) An annotated catalogue of fish-like vertebrates and fishes of the seas of Russia and adjacent countries: Part 3. Orders Perciformes (excluding suborders Gobioidei, Zoarcoidei and Stichaeoidei) and Tetraodontiformes. Journal of Ichthyology, 43, S 1 - S 40.","Robertson, D. R. & Allen, G. R. (2002) Shorefishes of the tropical eastern Pacific: an information system. CD-ROM. Smithsonian Tropical Research Institute, Balboa, Panama.","Collette, B. B. & Aadland, C. R. (1996) Revision of the frigate tunas (Scombridae, Auxis), with descriptions of two new subspecies from the eastern Pacific. Fishery Bulletin, 94, 423 - 441.","Collette, B. B. (2003) Family Scombridae Rafinesque 1815. Mackerels, tunas, and bonitos. California Academy of Sciences Annotated Checklists of Fishes, No. 19."]}

Kawakawa Euthynnus affinis, also known as eastern little tuna or mackerel tuna, is a species of tuna (Thunnini tribe, subgroup Pelagiaria clade) (Sanciangco et al., 2016). Tuna includes 15 species: eight of genus Thunnus (true tuna) and seven “tuna-like” of four genera: Allothunnus, Auxis, Euthynnus, and Katsuwonus. E. affinis is widely distributed throughout the tropical and subtropical waters of the continental shelf areas of the Indo-Pacific region (Collette, 2001). The fish reaches a length of 45–60 cm and matures at approximately 3 years of age. It inhabits almost exclusively the upper layers of the ocean (Bernal et al., 2017) and feeds mainly on small pelagic fish (Griffiths et al., 2009). E. affinis makes up a substantial proportion of the commercial and artisanal fishery in many countries of the Indo-Pacific region. The meat of E. affinis is of high quality (Mukundan et al., 1979) with a comparatively high level of docosahexaenoic acid (Saito et al., 1999), but deteriorates rapidly if not properly handled (Mukundan et al., 1979). E. affinis exhibits the swimming mechanics of true tunas (Donley and Dickson, 2000) but has no swim bladder and differs from true tunas in red muscle distribution, allometry, and vascular anatomy (Bernal et al., 2017). The ability to maintain an elevated temperature in eye, brain, and red muscle has been suggested for the genus Euthynnus (Dickson et al., 2000), but reports specific to E. affinis are lacking. Compared to true tunas, E. affinis has received scant attention from researchers, and little is known about its biology and physiology. This is likely to change, as E. affinis has recently become of interest in marine aquaculture. E. affinis is the second tuna species whose full-life cycle culture in captivity has been developed so far, including spawning, egg collection, incubation, larval rearing, and grow-out to marketable size (Yazawa et al., 2015, 2016). Aquaculture in general is currently facing significant challenges to increasing production while maintaining sustainability (Bridson et al., 2020). Genetic improvement, via selective breeding and genetic engineering, is a major focus of research and can yield rapid benefits to efficient production in fish farming (Lu and Luo, 2020). To these ends, a high-quality species genome assembly is critical. Despite recent advances in sequencing technologies and genomics that, in addition to basic fish science (Lien et al., 2016; Hughes et al., 2018; Yuan et al., 2018; Du et al., 2020), have applications to aquaculture practices (Lu and Luo, 2020) and fisheries (Benestan, 2020), genomic information of tuna species is limited. To date, the genomes of only three tuna species are available in the public repositories, none of which are assembled to chromosome level. This situation exists within the entire Pelagiaria clade that, along with tuna, includes the economically important mackerel (Scombrini tribe) and bonito (Sardini tribe). Here, we report the chromosome-level genome assembly of kawakawa E. affinis (NCBI:txid8227). To our knowledge, this is the first available chromosome-level assembly within the Pelagiaria clade. The reported genome assembly is accompanied by transcriptome assembly, genetic linkage map, annotation of transposons, repetitive elements, and 23,059 genes. The dataset provides a solid genome resource not only for further study of E. affinis basic biology and genome-scale selective breeding but also for enhancing both basic and applied research within the Pelagiaria clade.

Auxis rochei (Risso, 1810) – Bullet tuna, Κοπάνι/τορνέτα Maximum length for bullet tuna is around 50 cm and maximum weight is around 1.9 kg, depending on the fishing area they come from (Valeiras & Abad 2006b). Common length in the Aegean is 36-38 cm. It is widely distributed in the Mediterranean and the Black Sea. Bullet tuna are preyed upon by tuna, sharks and dolphin fish. They have a strong schooling behavior and they form large schools of similar sized individuals. They are often confused with Auxis thazard, which are morphologically similar (but rather uncommon in the Aegean). In the summer they swim near the surface and approach land, while in the winter they move to deeper waters. They are mostly caught with surface gear (Valeiras & Abad 2006b; Papanastasiou 1976: 498, 499). In the Aegean (especially its eastern coasts) the spawning period is reported to be from May to September with the peak observed in June, July and August (Bök & Oray 2001; Kahraman et al. 2010: 6816). Bullet tuna is caught in all parts of the Aegean, the only restricting factor being the accessibility of certain areas to the dominant fishing gear (in this case, the round nets called gri-gri in Greek and Turkish) (Koli & Platis 1998: 33). In the spring catches, most of the fish are 34-36 cm in length, while the smallest ones are 28-30 cm. In summer catches the most common size is 18-20 cm long, while some individuals can be very small indeed (10-12 cm) Koli & Platis 1998: 64, 65)., Published as part of Mylona, Dimitra, 2021, Catching tuna in the Aegean: biological background of tuna fisheries and the archaeological implications, pp. 23-37 in Anthropozoologica 56 (2) on page 29, DOI: 10.5252/anthropozoologica2021v56a2, http://zenodo.org/record/4486342, {"references":["VALEIRAS J. & ABAD E. 2006 b. - Description of Bullet tuna. ICCAT Manual (2.1.10.2): 209 - 216.","PAPANASTASIOU D. 1976. - AΛΙΕUμΑΤΑ Vol. A. ' Ιων, Athens, 655 p.","BOK T. & ORAY I. K. 2001. - Age and growth of bullet tuna Auxis rochei (Risso, 1810) in Turkish waters. Collective Volume of Scientific Papers ICCAT 52 (2): 708 - 718.","KAHRAMAN A. E., GOKTURK D., BOZKURT E. R., AKAYLI T. & KARAKULAK F. S. 2010. - Some reproductive aspects of female bullet tuna, Auxis rochei (Risso), from the Turkish Mediterranean coasts. African Journal of Biotechnology 9 (40): 6813 - 6818.","KOLI A. & PLATIS K. 1998. - ΒΙΟΛΟΓΙΑ ΚΑΙ ΑΛΙΕΙΑ ΤωΝ Auxis sp. ΣΤΟΝ ΕΑΑδΙΚΟ χωΡΟ. Πτυχιακη ΕΡγασια, Τ. Ε. Ι. ΜΕσολοDιου. ΜΕσολοDι 129 P."]}

This study was conducted to develop systems for the identification of four tuna species (skipjack tuna Katsuwonus pelamis, yellowfin tuna Thunnus albacares, bullet tuna Auxis sp. and Atlantic bonito Sarda sp). At first, raw samples of these species and a mix intended as internal control were prepared for the authentication of fish muscle tissue of the genus Thunnus sp., Auxis sp. and Sarda sp. DNA from raw muscle tissue, the mix and samples was extracted with the DNeasy mericon Food Kit (Qiagen GmbH, Hilden, Germany). The concentration and purity of DNA in raw samples were evaluated using a spectrophotometer. Primers and probe sequences were specifically designed to identify the selected species. In addition, primers and a probe for the endogenous 12S rRNA gene were designed to determine the presence of amplifiable fish (especially tuna) DNA in samples. Furthermore, the species specificity of the designed primers and probes was verified in DNA samples of various tuna and bonito species. Limit of detection for the selected species was calculated as well as the coefficient of determination R2 and efficiency of real-time PCR testing was determined. To evaluate the developed real-time PCR methods, 70 commercial tuna products were analysed. The results show that mislabelling of fish products can still be encountered and, moreover, the presence of an additional species can be identified.

Auxis rochei (Risso 1810) ���Bullet tuna Taxonomy. First record from Lebanon as Auxis rochei (Risso) by Mouneimn�� (1977: 64); subsequently recorded as Auxis rochei (Risso 1810) by Mouneimn�� (2002: 223���224); recently recorded as Auxis rochei by Bariche et al. (2007: 112). Material in collection: USNM. Distribution. Circumglobal in tropical through temperate seas (including western Baltic Sea, North Sea, Mediterranean Sea, Black Sea, Persian Gulf, South China Sea), but not eastern Pacific. Conservation. IUCN: Global (LC: 17 September 2010); Med. (LC: 15 November 2007). Capture and threats: FIT, FIB, Unknown. Occurrence: Common. Low priority for conservation action., Published as part of Bariche, Michel & Fricke, Ronald, 2020, The marine ichthyofauna of Lebanon: an annotated checklist, history, biogeography, and conservation status, pp. 1-157 in Zootaxa 4775 (1) on page 82, DOI: 10.11646/zootaxa.4775.1.1, http://zenodo.org/record/3983887, {"references":["Mouneimne, N. (1977) Liste des poissons de la cote du Liban (Mediterranee orientale). Cybium, 3 (1), 37 - 66.","Mouneimne, N. (2002) Poissons marins du Liban et de la Mediterranee orientale. INCAM-EU / CNRS Lebanon, Beyrouth, 271 pp.","Bariche, M., Sadek, R., Al-Zein, M. S. & El-Fadel, M. (2007) Diversity of juvenile fish assemblages in the pelagic waters of Lebanon (eastern Mediterranean). Hydrobiologia, 580, 109 - 115. https: // doi. org / 10.1007 / s 10750 - 006 - 0461 - 0"]}

Auxis thazard (Lacep��de 1800) ���Frigate tuna Taxonomy. First record from Lebanon as Auxis thazard (Lac��p��de 1802) by George et al. (1964: 21). Distribution. Circumglobal in tropical through temperate seas (including Mediterranean Sea, Red Sea, Persian Gulf, South China Sea), but not in eastern Pacific. Material in collection: AUBM and BMNH. Conservation. IUCN: Global (LC: 14 September 2010); Med. (LC: 15 November 2008). Capture and threats: FIT, FIB, Unknown. Occurrence: Common. Low priority for conservation action., Published as part of Bariche, Michel & Fricke, Ronald, 2020, The marine ichthyofauna of Lebanon: an annotated checklist, history, biogeography, and conservation status, pp. 1-157 in Zootaxa 4775 (1) on page 82, DOI: 10.11646/zootaxa.4775.1.1, http://zenodo.org/record/3983887, {"references":["George, C. J., Athanassiou, V. A. & Boulos, I. (1964) The fishes of the coastal waters of Lebanon. Miscellaneous Papers in the Natural Sciences. The American University of Beirut, 4, 1 - 24."]}

The feeding ecology and consumption rate of the broadbill swordfish (SWO, Xiphias gladius) from Ecuadorian waters were assessed by stomach content analysis of 256 individuals ranging between 91 and 291 cm in straight fork length (FL). Based on the alimentary index (%AI), the jumbo squid (Dosidicus gigas) was the most important prey species (58.93%AI), followed by bullet and frigate tunas (Auxis spp.) (17.94%AI). Permutational multivariate analysis of variance (PERMANOVA) detected one size-related shift in feeding habits to occur at FL ~ 190 cm, whereas no spatial variations in diet composition were observed. Similarity percentages (SIMPER) analysis revealed that the diet of small SWO (≤ 140 cm FL) and medium SWO (140–190 cm FL) was mainly characterized by Dosidicus gigas (contributing to 50.77 and 66.82% of the similarities, respectively) and Auxis spp. (18.14 and 17.23%, respectively); Auxis spp. and Thysanoteuthis rhombus, however, were the greatest contributors to the similarity in large SWO (≥ 190 cm FL) (47.87 and 22.06%, respectively). The daily meal was estimated to be 468.03–676.78 g day−1, which corresponded to a daily ration of 1.63–8.24% body mass (BM, in g) day−1. The results of this study indicate that the SWO is a mesopelagic predator that plays an important role in structuring the pelagic ecosystem of the Ecuadorian Pacific Ocean.

Size-related shifts in feeding habits of juvenile yellowfin tuna (YFT), Thunnus albacares (Bonnaterre, 1788), in Ecuadorian waters were assessed using stomach content analysis (SCA) (n = 339) and stable isotope analysis (n = 83). In all size classes, fishes were the predominant prey group in the diet (Alimentary Index, %AI = 96.86) followed by cephalopods (%AI = 3.29) and crustaceans (%AI = 0.03). PERMANOVA analysis revealed significant variations in diet with body size: i) Class I YFT (≤50 cm in fork length, FL) fed mainly on laternfishes, family Myctophidae (%AI = 37.34), and jumbo squid, Dosidicus gigas (%AI = 36.06), Class II YFT (50–60 cm, FL) consumed bullet and frigate tunas, Auxis spp., unidentifiable fish and jumbo squid (%AI = 47.75, %AI = 25.06 and%AI = 21.67, respectively), and Class III YFT (≥ 60 cm, FL) preyed almost exclusively on bullet and frigate tunas (%AI = 90.85). Mean ± SD muscle isotope values were 12.14 ± 1.95‰ for δ15N and −17.42 ± 0.27 for δ13C‰; mean (±SD) liver values were 11.30‰ for δ15N and −17.42 ± 0.27‰ for δ13C. Overall, liver and muscle samples showed significant size-related differences in δ15N and δ13C. Stable isotope Bayesian ellipses, SEAc, did not show trophic overlap among size classes. A significant positive linear correlation was observed between δ15N and δ13C measured in liver and muscle tissues with body size, suggesting an increase of prey size as tuna grew. These results indicate that the observed size-related diet shifts are not only related to prey type, but also to prey size.

Summer ichthyoplankton surveys were conducted in the northern Gulf of Mexico from 2007 to 2010 to characterize the distribution and abundance of tuna larvae. Larval assemblages of tunas were comprised of four genera: Thunnus, Auxis, Euthynnus, and Katsuwonus. Thunnus were the most abundant and four species were detected; T. atlanticus [blackfin tuna], T. obesus [bigeye tuna], T. albacares [yellowfin tuna], and T. thynnus [bluefin tuna]. Intra- and inter-annual variability in the distribution and abundance of Thunnus species were observed with higher densities in 2008 and 2009, with a decline in abundance observed in 2010. Distribution and abundance of Thunnus larvae were influenced by physical and chemical conditions of the water mass, notably sea surface temperature and salinity. Distinct species-specific habitat preferences were observed and the location of mesoscale oceanographic features influenced larval abundance with higher densities of T. atlanticus, T. obesus, and T. albacares near anticyclonic (warm core) regions and the Loop Current, while T. thynnus was observed in higher densities near cyclonic (cold core) regions. This study demonstrates that spatial and temporal variability in the location of mesoscale oceanographic features may be important to partitioning nursery habitat among Thunnus species.

Based on hydrographic data and vertical distributions of tropical species of fish larvae (Diogenichthys laternatus, Vinciguerria lucetia, Bregmaceros bathymaster, and Auxis spp.), effects of “Godzilla El Nino 2015–2016” in the shallow oxygen minimum zone off Mexico were analyzed. Zooplankton samples were collected during four cruises, before (February 2010 and April 2012) and during (June 2015 and March 2016) the warm event. Temporal series of sea surface temperature revealed that June 2015 was the warmest June of the last years. Conservative temperature was >2°C higher than normal in the surface mixed layer, and the suboxic layer (4.4 µmol/kg) reached as shallow as 100 m depth. Unexpected results were that larval abundances were relatively high during the warm event, unlike zooplankton volumes, which declined. Before the warm event, V. lucetia and Auxis spp. were more abundant in the surface mixed layer, while B. bathymaster and D. laternatus dominated in the thermocline and shallow hypoxic layer (44 µmol/kg). However, during the event in June 2015, all species were most abundant in the surface mixed layer, which implied that the species adapted to hypoxia had inverted their normal pattern of distribution, possibly as consequence of the rise of the suboxic layer; however, further observations are required to confirm this generality. Results showed no dramatic change in the total larval abundance during the warm event. Nevertheless, a differential response in their vertical distribution was evident in association with changes in the depth of the shallow hypoxic and suboxic layers. This might indicate adaptability of tropical species to prolonged periods of warming in the oceans.

This study was aimed at examining the phylogenetic and morphometric relationship of frigate tuna (Auxis thazard) and bullet tuna (Auxis rochei) using mtDNA D-loop (control) region sequences and truss measurements, respectively. Maximum-likelihood (ML) tree and median-joining network showed that haplotypes from Auxis populations grouped separately. Discriminant function analyses and non-metric multidimensional scaling of morphometric data showed that bullet and frigate tuna were differed mainly with respect to truss measurements on the anterior region, suggesting adaptation to different diets available in different environments. Historic demographic analyses of sequence data showed that both bullet and frigate tuna had not undergone a significant sudden population expansion recently. Non-significant value of Tajimas’s D and Fu’s FS were indicated an effective large and stable population size for longer period of both species in South China Sea and Java Sea species. This study gives first report on the complementary relationship between morphometric and genetic analysis in stock discrimination of genus Auxis.

Auxis rochei is one of genus Auxis and widely distributed in tropical and subtropical waters. In this study, we described the complete mitochondrial genome of A. rochei. The genome is 16505 bp in l...

Auxis thazard is one of genus Auxis and widely distributed in tropical and subtropical waters. In this study, we described the complete mitochondrial genome of Auxis thazard. The genome is 16,506 b...

Stomach content analysis (SCA) and stable isotope analysis (SIA), coupled with isotopic-mixing model analysis, were used to estimate diet composition of sailfish Istiophorus platypterus in eastern Taiwan waters. SCA provided information on diet, but the high occurrence of empty stomachs (48.5%) limited this analysis. According to the index of relative importance (%IRI), the most important prey items were Priacanthus macracanthus (38.7%), followed by Auxis spp. (35.9%), and Trichiurus lepturus (8.5%). However, the most important prey groups for adult sailfish (>181 cm, LJFL) as estimated by the stable isotope-mixing model were T. lepturus (32.6%), Katsuwonus pelamis (15.8%), and P. macracanthus (11.3%), and for maturing sailfish were K. pelamis (12.9%), P. macracanthus (10.4%), and T. lepturus (32.6%), respectively. Juvenile sailfish feed primarily on smaller prey items with lower δ15N values, while adult sailfish preferred larger prey items with higher δ15N values. Our findings suggested that an integrated SCA and SIA is considerably more powerful than using SCA alone in determining diet composition of sailfish over long time scales. In summary, a high diversity in the diet composition of sailfish was found and included an array of coastal, benthic, pelagic, and mesopelagic species. Sailfish are most likely opportunistic feeders consuming the most abundant prey items in eastern Taiwan waters.

The feeding habits of Makaira nigricans, Kajikia audax, Istiophorus platypterus (Istiophoridae), and Xiphias gladius (Xiphiidae) in the southeast Pacific Ocean were examined in Manta and Santa Rosa, Ecuador. This study describes the diets of these billfish species, evaluates dietary differences between species, and assesses seasonal differences in diet. A total of 274 M. nigricans, 321 K. audax, 267 I. platypterus, and 252 X. gladius were collected between February 2014 and April 2015. The scombrid Auxis spp. was the most important prey for M. nigricans, K. audax and I. platypterus, while the squid Dosidicus gigas was the most important prey for X. gladius. The results of the ANOSIM confirmed significant differences in feeding habits between the members of the family Istiophoridae and X. gladius. Seasonal differences for I. platypterus also were observed. Billfishes are specialist consumers with a narrow niche breadth (B a: M. nigricans and K. audax=0.1, I. platypterus=0.05, and X. gladius=0.04). RESUMEN Los hábitos alimentarios de Makaira nigricans, Kajikia audax, Istiophorus platypterus (Istiophoridae) y Xiphias gladius (Xiphiidae) en el Océano Pacífico sudeste se examinaron en Manta y Santa Rosa, Ecuador. Este estudio describe las dietas de estas especies de peces de pico, evalúa las diferencias de la dieta entre especies y las diferencias estacionales en la dieta. Se obtuvo un total de 274 M. nigricans, 321 K. audax, 267 I. platypterus y 252 X. gladius entre febrero 2014 y abril 2015. El escómbrido Auxis spp. fue la presa más importante para M. nigricans, K. audax y I. platypterus, mientras que el calamar Dosidicus gigas fue la presa más importante para X. gladius. Los resultados de ANOSIM confirmaron diferencias significativas en los hábitos alimentarios entre los miembros de la familia Istiophoridae y X. gladius. También se observaron diferencias estacionales para I. platypterus. Los peces de pico son consumidores especialistas con una amplitud de nicho estrecha (B a: M. nigricans y K. audax=0.1, I. platypterus=0.05 y X.gladius=0.04).

A–ktener A, AlaAŸ A, TA¼rker D. 2017. Two new hosts for Caligus bonito Wilson C.B., 1905 (Copepoda, Siphonostomatoida, Caligidae) from Turkey. Bonorowo Wetlands 7: 1-3. Caligus bonito Wilson C.B., 1905 (Copepoda, Siphonostomatoida, Caligidae) was reported for the first time on the gill filaments of Sarda sarda (Bloch, 1793), Auxis rochei (Risso, 1810) from Turkish marine waters.The morphological characters of this cosmopolitan parasitic copepod are given using photographs. This study aims to present two new host species and a new geographic distribution of Caligus bonito in Turkey.

The Fishing Industry in the Philippines plays an important role in the food and employment need of Filipino fishers. By using anchored Fish Aggregating Devices (FADs or payao), the Philippine tuna fisheries was transformed into a million-dollar industry. Minimal studies on exploitation rates and fish behaviour around anchored FADs hampered further understanding of this fishery practice. Studies on fish behavior using Local Ecological Knowledge (LEK) are good complement where data is limited. A study using semi-structured interview (n=46) and three focus group discussions (n=39 participants) to record fishers’ knowledge and observations on the behavior of different fish species around anchored FADs was conducted. This particularly focused on attraction, retention, and departure behaviour of fishes in identified FAD sites. Based on the fishers’ knowledge, tuna schools are attracted to anchored FADs at 10 km distance. In anchored FADs, tuna form schools segregated by species and size. There was no relationship between the attraction distance and the reported school size and the various waiting times for fish to aggregate below the FADs. There was no variation between the species present at day or night time although fishers have reported a distinction of species found near the surface (0-10 m) and those found at other depths (11-20 m). Juvenile yellowfin tuna (Thunnus albacares), skipjack (Katsuwonus pelamis) and frigate and bullet tunas (Auxis spp.) are found to stay at 25-50 m from the FAD at a depth of >20 m. Adult oceanic tunas reside in deeper waters (75 m). The fish visual census produced similar results with the semi-structured interviews and FGDs but did not observe oceanic tunas at depths of 15-20 m in the anchored FADs examined.

In order to assess the DNA sequence variation and phylogenetic relationship among five tuna species (Auxis thazard, Euthynnus affinis, Katsuwonus pelamis, Thunnus tonggol, and T. albacares) out of all four tuna genera, partial sequences of the mitochondrial DNA (mtDNA) D-loop region were analyzed. The estimate of intra-specific sequence variation in studied species was low, ranging from 0.027 to 0.080 [Kimura's two parameter distance (K2P)], whereas values of inter-specific variation ranged from 0.049 to 0.491. The longtail tuna (T. tonggol) and yellowfin tuna (T. albacares) were found to share a close relationship (K2P = 0.049) while skipjack tuna (K. pelamis) was most divergent studied species. Phylogenetic analysis using Maximum-Likelihood (ML) and Neighbor-Joining (NJ) methods supported the monophyletic origin of Thunnus species. Similarly, phylogeny of Auxis and Euthynnus species substantiate the monophyly. However, results showed a distinct origin of K. pelamis from genus Thunnus as well as Auxis and Euthynnus. Thus, the mtDNA D-loop region sequence data supports the polyphyletic origin of tuna species.

Based on morphometric studies, the vertebral column of the frigate tuna. Auxis thazard, can be divided into three morphologically distinct regions; postcranial, middle and ural. Biometrical measurement of the length, height and width of the vertebral column of Auxis thazard allows vertebral profiles with characteristic features to be drawn. The differences in length of vertebrae present in different regions of the vertebral column cause regionalization in this structure. These morphologically descriptive parameters express a morphotype which seems to have a functional link with the frigate tuna's thunniform mode of swimming. Morphology, vertebrae, regionalization, frigate tuna, Auxis, The Sea of Oman.

The marine environment of the Santa Marta region (Colombian Caribbean) is unique in many ways. The coexistence there of both species of Auxis is herewith reported and discussed. Auxis thazard, the frigate tuna or frigate mackerel, has been reported several times from Santa Marta; however, the occurrence of A. rochei, the bullet tuna or bullet mackerel, is reported for the first time. Some inter and intraspecific differences are discussed; fishery aspects are commented as well.

The variability of mesoscale circulation structures in the Gulf of Mexico (GOM) was examined using satellite altimeter data collected between 1992 and 2008, and linkages between ocean circulation and the spatial distribution of larval fish were assessed. The abundance and dis- tribution of the larvae of 5 pelagic fish taxa (Auxis spp., Euthynnus alleteratus, Thunnus thynnus, other Thunnus spp., and Coryphaena spp.) were estimated from surveys conducted by the National Oceanic and Atmospheric Administration National Marine Fisheries Service each spring between 1993 and 2007. We observed a tendency for higher northward extension of the Loop Current (LC) during spring each year, with maximum northern penetration in summer, although the exact location of the LC varied from year to year. Generally, higher total larval abundances occurred during years of high northward penetration in a region that was crossed by the LC during its excursions. However, the interannual variability of the LC was not mirrored in a general increase or decrease of larval fish densities in the water masses out of the LC front. Further, the results show that larvae of T. thynnus and Auxis spp. were more abundant within the boundaries of anticyclonic features (usually between 148 to 158 cm of sea surface height) and within GOM common waters, defined as the background waters in between the boundaries of mesoscale features. Our findings suggest that the position and strength of anticyclone mesoscale features in the GOM define a favorable spawning habitat for the species examined.

Eleven individual larvae (3.6-8.0 mm notochord length, NL) were collected from the southern East Sea of Korea in July, 2010, and the adjacent Sea of Jeju Island in August, 2011. Five individuals were identified using mitochon-drial DNA cytochrome oxidase subunit I (COI) sequences (494 base pairs). All were identified as Auxis rochei, their mtCOI sequences being consistent with those of adult A. rochei (d=0.000), followed by Auxis thazard (d=0.027). In terms of morphology, A. rochei larvae showed a preflexion stage of 4.8 mm NL, but a flexion stage between 5.2-6.2 mm NL, and subsequently a postflexion stage between 6.6-8.0 mm NL. During the larval stage, A. rochei differed from A. thazard in having no (or few) melanophores in the lateral caudal region. Key words : Auxis rochei, Lavae, Identification, mtCOI, Morphological development

In the summer period of 2009, two species of warm-water fish—Japanese cutlass fish Trichiurus japonicus and frigate mackerel Auxis thazard—were found in Peter the Great Bay. Their description is made, and their main diagnostic characters are provided. It was established that both species of the genus Auxis are found in Russian waters of Far Eastern seas.

Gel properties of croaker surimi blended with three types of mackerel surimi at different ratios were evaluated. The gel strength of the croaker–mackerel surimi blend was higher than that of the original mackerel surimi ( p p > 0.05). The addition of short-bodied mackerel surimi into croaker surimi up to a ratio of 1:2 had no effect on whiteness and metmyoglobin content of the gel ( p > 0.05). Marked decrease in expressible drip and TCA-soluble peptide of gel was noticeable in croaker–frigate mackerel surimi blend ( p

Critical gaps in our understanding of the distributions, interactions, life histories and preferred habitats of large and medium-size pelagic fishes severely constrain the implementation of ecosystem-based, spatially structured fisheries management approaches. In particular, spawning distributions and the environmental characteristics associated with the early life stages are poorly documented. In this study, we consider the diversity, assemblages, and associated habitat of the larvae of large and medium-sized pelagic species collected during 2 years of monthly surveys across the Straits of Florida. In total, 36 taxa and 14,295 individuals were collected, with the highest diversity occurring during the summer and in the western, frontal region of the Florida Current. Only a few species (e.g. Thunnus obesus, T. alalunga, Tetrapturus pfluegeri ) considered for this study were absent. Small scombrids (e.g. T. atlanticus, Katsuwonus pelamis, Auxis spp.) and gempylids dominated the catch and were orders of magnitude more abundant than many of the rare species (e.g. Thunnus thynnus, Kajikia albida ). Both constrained (CCA) and unconstrained (NMDS) multivariate analyses revealed a number of species groupings including: (1) a summer Florida edge assemblage (e.g. Auxis spp., Euthynnus alleterattus , Istiophorus platypterus ); (2) a summer offshore assemblage (e.g. Makaira nigricans, T. atlanticus, Ruvettus pretiosus, Lampris guttatu s); (3) an ubiquitous assemblage (e.g. K. pelamis, Coryphaena hippurus, Xiphias gladius ); and (4) a spring/winter assemblage that was widely dispersed in space (e.g. trachipterids). The primary environmental factors associated with these assemblages were sea-surface temperature (highest in summer-early fall), day length (highest in early summer), thermocline depth (shallowest on the Florida side) and fluorescence (highest on the Florida side). Overall, the results of this study provide insights into how a remarkable diversity of pelagic species spatially and temporally partition spawning within a region that is characterized by dynamic oceanography and strong habitat gradients.

Monthly plankton sampling across the Straits of Florida (SOF) allowed for a thorough investigation of the feeding ecologies of four taxa of larval tunas (family Scombridae, tribe Thunnini) and the horizontal and vertical distributions of tuna larvae and their dominant prey. Before piscivory, Thunnus spp. larvae had a mixed diet of crustaceans and appendicularians, whereas skipjack tuna (Katsuwonus pelamis), little tunny (Euthynnus alletteratus), and Auxis spp. displayed highly selective and nearly exclusive feeding on appendicularians. The availability of both appendicularians and larval fish prey declined from west to east across the SOF, and appendicularians were notably patchy. In the western SOF where prey was more abundant, all taxa of tuna larvae co-occurred, indicating the sharing of resources by the larvae, in addition to the adults of these taxa using similar spawning habitat upstream in the Florida Current. In the central and eastern SOF, where prey was less abundant, only Thunnus spp. and skipjack tuna co-occurred, and these two taxa exhibited significantly different vertical distributions. Prey removal rates (estimated from gut evacuation rates and daily rations) occurring in the western SOF where tuna taxa co-occurred are likely to be sustainable by appendicularian levels within this region but would potentially not be by levels in the east. The spatial and trophic characteristics of these four abundant larval taxa highlight the potential influence of feeding-related processes on larval and adult behavior, while also illustrating a critical trophic link to the microbial food web provided by appendicularians in this oligotrophic environment.

Fronts and eddies are widely hypothesized to be critical spawning habitat for large pelagic fishes, due to increased larval and/or adult feeding opportunities at these features. We examined sailfish (Istiophorus platypterus) spawning around a cyclonic, submesoscale (∼13 × 7 km) Florida Current frontal eddy. The temporal progression of eddy dynamics over a 65 h period was determined using ocean color satellite imagery, continuous surface measurements along the cruise track, and non-linear least-squares fitting of the positions of three drifters deployed within the eddy. A peak in larval sailfish densities (n = 2435, stations = 49), composed primarily of yolk-sac and first-feeding larvae, occurred at the eddy frontal zone. A majority of these larvae were estimated to have been spawned during the formation of the eddy. A comparison between the distribution of similar-age sailfish and scombrid larvae indicated that the peak in larval sailfish density likely resulted from spawning directly at the front, rather than transport by convergent flow. The first-feeding prey items of larval sailfish (Farranula and Corycaeus copepods) were most abundant at the frontal zone and to a lesser extent inside the eddy. Egg distributions were used to indirectly assess the distribution of adult sailfish prey items. Euthynnus alleteratus and Auxis spp. eggs were in highest abundance outside the eddy, while the eggs of small carangids were in highest abundance at the eddy frontal zone. Overall, this study indicates that sailfish spawn at small-scale oceanographic features that provide a favorable feeding environment for their larvae and potentially also for the adults.

The fish remains are described that were found at the bottom of an Early Roman ceramic jar from Aila Aqaba, Jordan. The bones, representing the gill apparatuses of at least 33 medium-sized tunas (Auxis; Scombridae) and a single individual of a lizardfish (Trachinocephalus myops; Synodontidae), are believed to correspond to haimation. This highly prized fish sauce, documented previously only from ancient textual evidence, was typically made from the gills and the entrails of tunnids to which salt was added. The sauce was not imported from the Mediterranean or the Black Sea, but made from local Red Sea fish as shown by the zoogeographical distribution of the lizardfish that is considered as stomach content of the tunas. Because the fish bones were found in a locally produced jar and because the calculated volume of the haimation that the bones represent corresponds more or less to the volume of the jar, it is concluded that this high-quality garum was produced in this container at Aila itself.

The complete mitochondrial DNA sequence of the frigate tuna Auxis thazard and two divergent mitotypes (Mitotype I and Mitotype II) of the bullet tuna Auxis rochei have been determined. The total length of the mitogenomes was 16,506, 16,501 and 16,503 bp, respectively. All mitogenomes had a gene content (13 protein-coding, 2 rRNAs and 22 tRNAs) and organization similar to those observed in most other vertebrates. The major non-coding region (control region) ranged between 843 and 847 bp in length, and showed the typical conserved blocks. Phylogenetic analyses revealed a monophyletic origin of Auxis with respect to other tuna fish. Molecular data here presented provide a useful tool for evolutionary as well as population genetic studies.

The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was developed to identify the species of Thunnus thynnus , T . alalunga , T . obesus , T . albacares , Euthynnus pelamis ( Katsuwonus pelamis ), E . affinis , Auxis thazard and Sarda orientalis in products of canned tuna. To increase the efficiency and sensitivity of DNA extraction, a recent developed method of binding magnetic beads was applied in this study. Two sets of primer were designed to amplify 126 bp and 146 bp of partial mitochondrial cytochrome b gene, and five restriction enzymes including Bsp 1286I, Hin cII, Rsa I, Sca I and Mbo II were determined to analyze the short length fragments. The developed PCR-RFLP method was applied to authenticate species of 18 commercial canned tuna successfully, and it really provided a useful and academic technique to identify eight species in canned tuna.

Diet composition of the sailfish Istiophorus platypterus from the southern Gulf of California was determined using stomach contents of 576 fish. They were sampled from 1989 to 1991 from the sport fishing fleet at six tourist ports of the Mexican Pacific (La Paz, Cabo San Lucas, Mazatlan, Puerto Vallarta, Barra de Navidad, and Manzanillo). A total of 78 different prey taxa was classified and 64 were identified to species. From the diet composition and using the percent of index of relative importance (IRI), three feeding zones were determined by using cluster analysis. The most important prey by zones were in Zone I, La Paz: Dosidicus gigas, Scomber japonicus, and Auxis spp.; Zone II, Cabo San Lucas: Auxis spp., Selar crumenophthalmus, and Lagocephalus lagocephalus; and Zone III, Mazatlan, Puerto Vallarta, Barra de Navidad, and Manzanillo: Argonauta spp., D. gigas, and Auxis spp. We suggest that sailfish in Mexican Pacific waters are generalist predators feeding mainly on epipelagic species in coastal and oceanic waters, and occasionally diving to prey on demersal fish. The changes in diet composition among zones seem to be related more to abundance and distribution of the prey than to food preferences.

The head region of 72 bullet tuna Auxis rochei from the western Mediterranean Sea (south-east Spain and the Strait of Gibraltar) was examined for parasites. Seven metazoan species were found in the fish from south-east Spain: three monogeneans, two trematodes and two copepods, whereas only three species were isolated in the fish from the Strait of Gibraltar. A comparison of the levels of infection of the parasites according to fish size in south-east Spain showed that the prevalence of Didymozoon auxis and the mean abundance of Allopseudaxine macrova were higher in the larger hosts (range of fork length ¼ 38–44 cm) than in the smaller ones (33–37 cm). A comparison of the parasite infections according to geographical region showed that the mean abundances of Nematobothriinae gen. sp. and Caligus bonito were higher in fish from south-east Spain than in those from the Strait of Gibraltar. A comparison of the parasite fauna of A. rochei from the Mediterranean Sea with the published data on Auxis spp. from the Atlantic, Indian and Pacific Oceans revealed the closest similarity between the Mediterranean A. rochei and the Atlantic A. thazard., SI

* □ Auxis thazard thazard (Lacepède, 1800) – Frigate tuna; Judeu-liso ①, Chapouto ③, Published as part of Carneiro, Miguel, Martins, Rogélia, Landi, Monica & Costa, Filipe O., 2014, Updated checklist of marine fishes (Chordata: Craniata) from Portugal and the proposed extension of the Portuguese continental shelf, pp. 1-73 in European Journal of Taxonomy 73 on page 59, DOI: 10.5852/ejt.2014.73, http://zenodo.org/record/3866515

* □ Auxis rochei rochei (Risso, 1810) – Bullet tuna; Judeu ①②③, Published as part of Carneiro, Miguel, Martins, Rogélia, Landi, Monica & Costa, Filipe O., 2014, Updated checklist of marine fishes (Chordata: Craniata) from Portugal and the proposed extension of the Portuguese continental shelf, pp. 1-73 in European Journal of Taxonomy 73 on page 59, DOI: 10.5852/ejt.2014.73, http://zenodo.org/record/3866515

マルソウダから製造した魚醤油(FMS)の揮発性成分と, 国内産魚醤油(しょっつる(S), いわしいしる(IS), いかいしる(IJCS))および大豆こいくち醤油(SS)のそれを比較し, 揮発性成分と各魚醤油の匂いとの関係を検討した。FMSとSSでは揮発性の酸類(VA)が比較的少なく, アルコール類が多いが, SやISではVAが多かった。また, IJCSはVAが少なく酢酸のみが検出され, アルデヒド類が多かった。FMS, SSおよびIJCSに酷酸や吉草酸は検出されなかったが, SやISには検出された。官能評価では, FMSは, SSと同様に刺激のない好ましい香りをもつと評価されたが, S, ISおよびIJCSはやや刺激的でいやな香りをもつと評価された。さらに, IJCS以外の試料でVAとpHの間には強い正の相関が, また, 香りについての好ましさとpHの間には強い負の相関がみられた。

The camallanid nematode Oncophora melanocephala (Rudolphi, 1819) is redescribed from specimens collected in tunas, Thunnus thynnus (L), T. albacares (Bonnaterre), T. atlanticus (Lesson) and Auxis thazard (Lacepede) from the Atlantic littoral of Rio de Janeiro, Brazil. In addition to a specific structure of the buccal capsule, the species is characterized by the presence of seven pairs of preanal and five pairs of postanal subventral papillae in the male and by an unusual shape of body in the adult female; deirids are described for the first time in O. melanocephala . The structure of the buccal capsule of O. melanocephala , particularly the presence of a large posterior portion of capsule and a colourless connecting ring between buccal capsule and oesophagus, shows close affinities of Oncophora Diesing, 1851 with Paracamallanus Yorke et Maplestone, 1928. The findings of O. melanocephala in T. atlanticus and A thazard represent new host records.