Tesis sobre el tema "Billfish"

Atlantic billfish include sailfish (Istiophorus platypterus), blue marlin (Makaira nigricans), white marlin (Kajikia albida, formerly Tetrapturus albidus) and the spearfishes (Tetrapturus); these fishes are found in tropical and subtropical waters. The spearfishes include the longbill spearfish (T. pfluegeri), the Mediterranean spearfish (T. belone) and the roundscale spearfish (T. georgii). The International Commission for the Conservation of Atlantic Tunas (ICCAT) is the regional fishery management organization that conducts research to determine the condition of tuna and billfish resources and supports international cooperative management. ICCAT has determined that blue marlin and white marlin are overfished; the status of sailfish and spearfish are unknown, but overfishing is thought to be occurring. Management of these resources is complicated by uncertainty in the biological models, but uncertainty about the fishers who target these resources. This dissertation studied artisanal fishing fleets that target Atlantic billfish in Venezuela and Ghana, as well as studied recreational charter boat fishing fleets in South Florida and Senegal. The information from these fleets was used to develop performance indicators that evaluate the socioeconomic performance of these fleets. An allocation model was developed to determine the optimal allocation of billfish resources among recreational and artisanal fishers in Ghana, West Africa. Finally, the issues and challenges of managing Atlantic billfish were identified as well as a possible future framework. Results indicate that performance indicators can be used to contrast fleets with different operational objectives. Fishers do produce positive fishing profits in both artisanal and recreational fleets; however, Senegalese recreational anglers are particularly sensitive to fuel costs. Results of the allocation model suggest that the artisanal sector should be allocated 95% of the quota in Ghana. There is the possibility to over-allocate quota to the recreational sector due to methodological differences in determining benefit f and the practice of catch-and-release. ICCAT's limited purview over socioeconomics was identified as the major impediment to effective billfish management. Therefore, it is recommended that the institutional structure for billfish management be modified to include socioeconomic issues, most especially strengthening the link to local institutions in fishing communities.

The objective of this dissertation was to examine sailfish (Istiophorus platypterus) and blue marlin (Makaira nigricans) spawning in the Straits of Florida, with a specific focus on 1) the physical and biological characteristics of the spawning environment, and 2) the role of the region within the broader spawning patterns of these two species. In order to accomplish these objectives, two years of monthly ichthyoplankton collections and physical measurements across the Straits of Florida were combined with a finer-scale Lagrangian study. Additionally, a molecular species-identification methodology was developed that was both high-throughput and suitable for use with a broad taxonomic range of species. An initial analysis considered the diversity, assemblages and associated habitat of the larvae of large and medium size pelagic species. In total 36 species and 14,295 individuals were collected during this study, with the highest diversity occurring during the summer, and in the western frontal region of the Florida Current. Sailfish were included in an assemblage with Auxis rochei, A. thazard and Euthynnus alleterattus, all species found in highest abundance during the summer along the western edge of the Straits of Florida. Blue marlin grouped most closely with Thunnus atlanticus, Ruvettus pretiosus and Lampris guttatus, all summer spawners, whose larvae tended to occur further offshore. The primary environmental factors associated with these assemblages were SST (highest summer-early fall), day-length (highest early summer), thermocline depth (shallowest on the Florida side) and fluorescence (highest on the Florida side). A Lagrangian sampling effort was then used to more specifically evaluate the role of frontal zones in sailfish spawning. The results of this sampling indicated that the highest levels of sailfish spawning occurred in a frontal zone associated with the formation of a submesoscale frontal eddy. This spawning resulted in the first-feeding larvae occupying an area rich in prey items. Given the small spatial-scale of the front, and the distribution of the eggs of adult prey items, the results of this work would suggest that sailfish are actively targeting features for spawning that are favorable to the growth and survival of their larvae. Finally the relative importance of the Straits of Florida as a spawning ground was evaluated by calculating the annual egg production of both sailfish and blue marlin within this region. In total it was estimated that 2.1% of western Atlantic sailfish spawning and 1.6% of Atlantic wide blue marlin spawning occurs in the SF. Pop-up satellite tags deployed on sailfish at the start of the spawning season revealed their short residency times in the SF, suggesting that a large (≈10%) transient portion of the sailfish population is responsible for the SF egg production. These results indicate that the SF is a migratory bottleneck for sailfish. In conclusion the results of this study indicate that a hierarchy of physical and biological processes influence the distribution of billfish spawning in space and time. The results provide insights into the movement patterns and life history strategies of these species, and ultimately may aid in the development of the spatially explicit ecosystem based management approaches that are currently being advocated.

Recent evidence suggests that overfishing of large predatory fishes has resulted in substantial population declines and pelagic longline (PLL) fishing is a major contributor. The primary objective of this dissertation is understanding factors that affect the interactions between marine fish PLL fishing. These factors are important to determine vulnerability of bycatch and target species, especially when PLL catch and effort data are used to estimate stock abundance. Chapter 1 reviews 107 publications/reports on this topic. Results indicate that accurate characterization of PLL gear performance requires empirical measurement of horizontal and vertical gear movement; and pop-up satellite tags (PSATs) are best suited for quantifying pelagic fish vertical habitat use if: (i) sampling resolution and data storage are not a function of tracking duration and (ii) substantial monitoring durations are employed. This review documents the current state of knowledge for these factors and guidance for future research. In Chapter 2, hook time-at-depth was monitored for commercial PLL sets targeting swordfish, Xiphias gladius. Temperature-depth recorders (TDRs) were deployed at the hook, systematically along the entire gear length. Results indicated that: (i) hook depth predictions based on catenary geometry drastically overestimated actual fishing depths and (ii) using catenary geometry fails to capture within- and among-set variability, potentially resulting in biased stock assessments. Chapter 3 used temperature-depth data from PSATs on swordfish and blue marlin (Makaira nigricans) and similar data from TDR monitored near-surface and deep PLL fishing to determine the diel probability of these species encountering PLL hooks. Results indicated that blue marlin and swordfish inhabit surface waters at night with similar probability of encountering PLL hooks but may have different vulnerabilities due to temporal separation in feeding with blue marlin preferring daytime and twilight and swordfish preferring nighttime. Therefore, reducing fishing during daylight hours may reduce blue marlin bycatch during PLL targeting swordfish. Chapter 4 alternated non-offset and 10° offset circle hooks during PLL fishing and compared the relative performance on catch rates, percent mortality, and deep hooking percentage. Results indicated that 10° offset circle hooks can reduce fishing efficiency and conservation benefits commonly associated with circle hooks.

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The billfish are oceanic pelagic species often caught by the tuna fleet and with great interest of sport fishing. This group of fish has specific legislation prohibiting the marketing and export of two species, Kajuikia albida e Makaira nigricans, in Brazil. DNA barcode is a universal system of molecular identification based on a sequence of mitochondrial DNA cytochrome oxidase subunit I (COI) of about 650 base pairs, serving as an identifying genomic mark in each species. This system has been used successfully to identify mischaracterized samples illegally marketed, like sample materials from sharks and other endangered species of organisms. The Barcode DNA technique was used to identify billfish marketed in the second largest fishing warehouse in Latin America, the CEAGESP-SP and the international airport of São Paulo, Brazil. 302 samples of billfish were collected during three inspection actions carried out by IBAMA, the executing agency of the national environmental policy. After DNA sequencing procedures it was possible to identify 72 samples (91.14%) by CEAGESP at the level of species, being 21 (29.17%) identified as Xiphias gladius, 44 (61.1%) as Istiophorus platypterus and 7 (8.33%) as Kajikia albida, this latter species determined as a market prohibited in Brazil and considered vulnerable in the list of endangered species of the IUCN and in the official list of species of endangered Fauna - Fish and Aquatic Invertebrates. At the International Airport of Guarulhos it was possible to identify 223 samples (100%), all identified as Xiphias gladius as declared by the exporter and indicated by its NCM (Mercosur Common Nomenclature). Molecular analysis has proven to be an excellent tool to identify billfish in Brazil in different centers such as Guarulhos International Airport and CEAGESP, SP. The identification of the white marlin being illegally traded in CEAGESP demonstrates the ineffectiveness of the current monitoring techniques used and emphasize the need for adopting better public policies for the conservation of the species.
Os peixes de bico são espécies pelágicas oceânicas frequentemente capturadas pela frota atuneira e com grande interesse da pesca esportiva. Este grupo de peixes possui legislação específica que proíbe a comercialização e exportação de duas espécies, Kajikia albida e Makaira nigricans desse grupo no Brasil. O DNA Barcode é um sistema universal de identificação molecular baseado em uma sequência de DNA mitocondrial Citocromo Oxidase subunidade I (COI) de aproximadamente 650 pares de base, servindo como código de barras de DNA de cada espécie. Este sistema tem sido utilizado com êxito para identificar amostras que são comercializadas descaracterizadas e de forma ilegal, como tubarões e outras espécies ameaçadas de extinção. A técnica de DNA Barcode foi utilizada para a identificação de peixes de bico comercializados no segundo maior entreposto pesqueiro da América Latina, CEAGESP, SP e no Aeroporto Internacional de Guarulhos, atualmente o maior volume brasileiro de exportações de peixes de bico no País. Foram coletadas 302 amostras de peixes de bico durante vistorias realizadas pelo IBAMA, 223 no aeroporto e 79 no CEAGESP, órgão executor da política nacional do meio ambiente. Após sequenciamento do DNA foi possível à identificação das espécies de 70 amostras (88,60%) coletadas no CEAGESP, sendo 21 (30%) identificadas como Xiphias gladius, 43 (61,42%) como Istiophorus platypterus e seis (8,57%) como Kajikia albida, esta última de comércio proibido no Brasil, e considerada vulnerável pela lista de espécies em perigo da IUCN e pela Lista Nacional Oficial de Espécies da Fauna Ameaçadas de Extinção - Peixes e Invertebrados Aquáticos. No Aeroporto Internacional de Guarulhos foi possível à identificação de 223 amostras (100%), sendo todas identificadas como Xiphias gladius conforme declarado pelo exportador e indicado pelo seu NCM (Nomenclatura Comum do Mercosul). A análise molecular demonstrou ser uma importante ferramenta na identificação de peixes de bico comercializados no Brasil em diferentes centros como o Aeroporto Internacional de Guarulhos e CEAGESP, SP. A identificação de agulhões branco sendo ilegalmente comercializados na CEAGESP demonstra a ineficácia das técnicas de fiscalização utilizadas e enfatizam a necessidade melhores políticas públicas para a conservação da espécie.

Orientador: Fabio Porto-Foresti
Resumo: The billfish are oceanic pelagic species often caught by the tuna fleet and with great interest of sport fishing. This group of fish has specific legislation prohibiting the marketing and export of two species, Kajuikia albida e Makaira nigricans, in Brazil. DNA barcode is a universal system of molecular identification based on a sequence of mitochondrial DNA cytochrome oxidase subunit I (COI) of about 650 base pairs, serving as an identifying genomic mark in each species. This system has been used successfully to identify mischaracterized samples illegally marketed, like sample materials from sharks and other endangered species of organisms. The Barcode DNA technique was used to identify billfish marketed in the second largest fishing warehouse in Latin America, the CEAGESP-SP and the international airport of São Paulo, Brazil. 302 samples of billfish were collected during three inspection actions carried out by IBAMA, the executing agency of the national environmental policy. After DNA sequencing procedures it was possible to identify 72 samples (91.14%) by CEAGESP at the level of species, being 21 (29.17%) identified as Xiphias gladius, 44 (61.1%) as Istiophorus platypterus and 7 (8.33%) as Kajikia albida, this latter species determined as a market prohibited in Brazil and considered vulnerable in the list of endangered species of the IUCN and in the official list of species of endangered Fauna - Fish and Aquatic Invertebrates. At the International Airport of Guarulhos it ... (Resumo completo, clicar acesso eletrônico abaixo)
Mestre

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CAPES
O agulhão negro (Makaira nigricans) é uma espécie dentre os grandes peixes pelágicos que compõe o topo da teia trófica marinha, sendo sua preservação importante para a manutenção da dinâmica populacional desses ecossistemas. Esta espécie é uma das mais procuradas pela pesca esportiva no mundo, sendo, porém, alvo de sobrepesca devido sua captura frequente como fauna acompanhante na pesca de espinhel pelágico no oceano Atlântico. O objetivo do presente trabalho de pesquisa foi compreender os movimentos migratórios, a influência de fatores ambientais em padrões de movimento e utilização de habitat pelos agulhões-negro no oceano Atlântico Sul e como essa espécie interage com o aparelho de pesca. Para o levantamento de dados sobre a utilização de habitat foram utilizadas marcas PSATs (pop-up satellite archival tags) para monitorar o comportamento do animal registrando um fluxo quase contínuo de parâmetros ambientais especificados (temperatura, pressão [profundidade] e luminosidade), onde os dados são arquivados e transmitem a informação via satélite após se desconectarem do animal. Além disso, foram também analisadas as profundidades de atuação dos anzóis do espinhel na pesca comercial de atuns e afins no Atlântico Sul, para melhor compreender quanto o esforço de pesca atualmente empregado se sobrepõe ao habitat utilizado pelos agulhões. O deslocamento horizontal durante o período de marcação variou de 374 a 1.838 km. Os resultados mostraram que os indivíduos maiores (>195 cm), considerados adultos, apresentaram deslocamentos direcionais segundo a estatística circular aplicada, enquanto que indivíduos juvenis ou menores (<195 cm) apresentaram deslocamentos considerados loopings ou sem direcionamento definido. Os dados de tempo em profundidade nos mostraram que a os indivíduos passam a maior porcentagem do tempo em águas superficiais acima dos 20m durante os períodos noturno e diurno. Os agulhões negros permaneceram a maioria do tempo dentro de uma curta faixa de temperatura, com uma média de 57% do tempo em temperaturas entre 26º e 28ºC. Os resultados quanto a sobreposição de habitat à espinhéis pelágicos nos mostrou uma relação de 59% da área rastreada sobreposta às armadilhas de pesca. A média de profundidade dos anzóis registrada foi de 49 m, sendo 90% da distribuição de profundidade dos anzóis entre 3271m. Essa distribuição vertical quando sobreposta ao padrão de utilização vertical do habitat pelos agulhões, revelou uma sobreposição que varia entre 11% e 35% durante o período diurno e 21% e 34% durante a noite. Os resultados obtidos na presente pesquisa são relevantes para uma melhor compreensão da biologia e ecologia dos agulhões negros no oceano Atlântico Sul, compondo um importante conhecimento sobre o comportamento da espécie e auxiliando para tomada de decisões e medidas de manejo e conservação da espécie a nível internacional.
Blue marlin (Makaira nigricans) is a species among great pelagic fishes that occupy the top of marine food web, being its conservation important to the maintenance of ecosystem population dynamics. Atlantic blue marlin is one of the favorite species targeted by recreational fishing in the Atlantic Ocean, however being overexploited because of its frequent capture as bycatch by commercial pelagic longline fishery. The main goal of this study was to understand migratory movement and the influence of environmental factors in movement patterns and habitat utilization by blue marlins in the South Atlantic Ocean and how this species interacts with pelagic longline gear. Pop up archival tags (PSATs) were used to collect habitat utilization data monitoring animal behavior through continuous records of specified environmental parameters (temperature, pressure [depth] and luminosity), transmitting such reports via satellite after pop-off. Furthermore, was also analyzed longline gears hook depths from commercial fisheries in South Atlantic to better understand how this fishing effort overlap to marlins habitat utilization. PSATs were programmed to record depth, temperature, and light intensity for a period of 180 days until release. The horizontal net displacement for all blue marlins ranged from 374 to 1.838 km. Results presented that larger individuals (>196 cm), considered adults, achieved directional movements according to circular statistics applied, while shorter individuals (<195 cm) presented displacement as looping or nondirectional. Time-at-depth histograms of blue marlin habitat utilization show that most individuals across all areas spent the majority of their time in shallow waters, above 20m, both during the day and night periods. Blue marlins spent most of their time within a relatively narrow temperature range, staying an average of 57% of their time in temperatures between 26° and 28°C. Overall, blue marlins had approximately 59% of their tracked range overlapped by the longline fishing gear. The average hook depth across all areas was 49 m with 90% percentile depth distribution of the hooks depth between 32-71 m. When this distribution was overlapped with the species vertical habitat utilization, the overlap ranged between 11 and 35% during daytime and 21 and 34% during nighttime. The results achieved in this study are relevant to better understand the biology and ecology of Atlantic blue marlins, composing an important knowledge about species behavior, which reduces current uncertainties about its biology and help to making decisions and take international conservation and management measures to the species.

Biological and life history characteristics for a previously unstudied population of sailfish, Istiophorus platypterus, in the Arabian Gulf were investigated. Notable findings include temporal-spatial migration patterns for a genetically isolated population that is threatened by overexploitation. Conventional tagging resulted in 2053 releases and 114 recaptures (5.55%) inside the Gulf. Linear displacement ranged from 2.5 to 697 km, while days at liberty ranged from 17 to 818 days. Dead recoveries in Iranian gillnets account for 88.6% of recaptures. Modeling analyses produced a best estimate of annual survival probability (S) at 0.375 (slope = -0.101, SE = 0.324). Fifteen pop-up satellite archival tags were deployed on sailfish during 2001 - 2002 to track temporal and spatial movements. Extensive data from four tags showed 83.7% of time-at-depth was spent above 10 m with no significant difference (P < 0.05) in diel preference. Depth ranged from 0.0 m to 61.0 m, while temperature ranged from 19.7 ??C to 30.1 ??C. Small-scale movements of eight sailfish were measured using ultrasonic tracking for periods ranging from 3:33 to 53:06 hours. Track distances ranged from 5.5 to 78.5 km, while linear displacement ranged from 4.6 to 37.0 km. Average speed ranged from 0.29 to 0.75 m s-1. Vertical distributions showed 84.3% of time was spent above 10 m depth, even though water temperature showed negligible variation with depth. Mitochondrial DNA comparison of 147 sailfish produced 39 composite haplotypes using eight restriction enzymes. Significant differences occurred in the frequency between population groups inside and outside the Gulf (amova 34.8%, P < 0.01; FST = 0.356), along with evidence of restricted migration between them (average number of migrants, Nm = 0.903). Nine year classes (0-8) were determined from aging analysis of fin spines. Females (n = 50) ranged from 0 to 8 years, while males (n = 34) ranged from 0 to 6 years. Von Bertalanffy growth function indicated rapid growth during the first two years, after which males stabilized and females continued growing to a greater maximum mean length and weight. A comparison of allometric growth between sexes indicated no significant difference between length and other morphometric characters (P ranged 0.135 ??? 0.980).

Commercial pelagic longline fishers within the U.S. Atlantic, Gulf of Mexico, and Caribbean are required to report all fishing interactions per each gear deployment to NOAA’s Vessel Logbook Program of the Southeast Fisheries Science Center to quantify bycatch, increase conservation efforts, and avoid jeopardizing the existence of vulnerable species listed under the Endangered Species Act (ESA). To provide additional accuracy, the Pelagic Observer Program (POP) of the SEFSC deploys professionally trained observers on longline vessels to produce a statistically reliable subset of longline fisheries data. A comparison of self-reported (“unobserved”) datasets versus observer-collected (“observed”) datasets showed a general consistency for most target species but non-reporting or under-reporting for a number of bycatch species and “lesser-valued” target species. These discrepancies between catch compositions and abundancies regarding targeted species, species of bycatch concern, and species of minimum economic value can provide insight into increased fisheries regulations, stricter requirements, or additional observer coverage.

Billfishes (marlins, spearfishes, sailfishes and swordfish) are one of the fastest and largest marine apex predators, and perhaps their most recognizable attribute is their bill or rostrum. The proposed function for this novel structure has ranged from hydrodynamic enhancement to defensive weaponry. However, the most supported hypothesis for its function has been linked to feeding. Billfishes have been observed to subdue their prey with their rostrum, either stunning or cutting them into pieces before ingestion. Due to their large body sizes and pelagic lifestyles a thorough investigation of the function of this structure has been logistically challenging. The goal of my dissertation is to investigate the role of the rostrum during feeding from a functional, mechanical and morphological standpoint. By the use of interdisciplinary approaches that blend engineering with biology, the function of the rostrum and billfish putative feeding behavior was investigated. By the use of different approaches that involve morphological characterizations, histology, estimation of performance measurements such as bite force and the investigation architectural tradeoffs from geometric morphometrics analysis, my dissertation aims to characterized the role of the rostrum in billfishes as a possible adaptation for feeding. Results showed that the rostrum in billfishes is mechanically capable of acting as a feeding weapon; continuous stress distribution along its length suggest no particular point that could lead to breakage during feeding. Finite element analysis, as well as bending experiments suggest feeding behavior may be species specific and strictly associated with rostrum morphology. While istiophorids may be morphologically suited to strike their prey with a wide range of motions, swordfish appear to be specialized from a mechanical and hydrodynamic standpoint to hit their prey with lateral strikes. Biting performance is relatively low in these top predators compared to other non-billfish species suggesting the rostrum may facilitate prey processing reducing the need for powerful biting. However contrary to my expectations rostrum length was not a predictor of bite force. Skull variation was evident among billfish species. Swordfish, the species with the longest rostrum, had the smallest head and the lowest relative bite force whereas blue marlin, the species with the stiffer, most compact rostrum, had the largest head and one of the greatest relative bite forces. The shortbill spearfish showed a relatively low bite force indicating predatory success in this species may be linked to an extended lower jaw that may facilitate a speed efficient jaw during prey capture. Whether the rostrum in billfishes has evolved as an adaptation for feeding, remains uncertain. However results from this study demonstrate that rostrum material properties, morphology and head architecture, in addition to relatively low biting performance in billfishes, favor a role of prey capture for the rostrum.

The processes influencing larval fish survival in the low-latitude open ocean are poorly understood, especially with regard to feeding. As part of a large-scale study that included two years of monthly sampling in the Straits of Florida (SOF), the objectives of this dissertation were to elucidate the larval fish feeding behaviors and strategies of 1) istiophorid billfishes, 2) tunas, and 3) coral reef fishes, while also 4) characterizing the feeding environment, synthesizing the dominant trophic pathways to fish larvae, and reviewing the literature for evidence of latitudinal distinctions in larval fish trophodynamics. Larval billfishes exhibited highly selective feeding, and their diets were numerically dominated (90%) by two genera of crustaceans, Farranula copepods and Evadne cladocerans. These prey were consumed throughout early larval ontogeny, from first-feeding through piscivorous lengths (> 5 mm), until piscivory became exclusive near 12 mm. High feeding incidence (0.94) and rapid digestion (~3.5 hrs) suggests frequent and successful feeding by billfish larvae. For tunas, nearly all larvae examined (>98%) contained prey. Thunnus spp. exhibited a mixed diet, while skipjack, little tunny, and Auxis spp. nearly exclusively consumed appendicularians. All four tuna taxa co-occurred in the western SOF where prey was more abundant, while in the central and eastern SOF (where prey availability was lower), only Thunnus spp. and skipjack were present. Additionally, these two taxa exhibited significantly different vertical distributions. Estimates of predatory impact indicated the potential for depletion of resources in the absence of the spatial and dietary niches of larval tunas. Coral reef fish families examined included Serranidae, Lutjanidae, Mullidae, Pomacentridae, Labridae, Scaridae, and Acanthuridae. Feeding incidences were high (0.94 to 1.0) for all taxa except scarids (0.04), and diets were narrow and predator-specific. Cluster analysis yielded clear groupings based on the selective feeding exhibited by the taxa, while within taxa, canonical correspondence analysis illustrated the change in diet with a variety of variables. The physical and biological environment varied markedly across the SOF, largely influenced by the Florida Current. Characteristics examined included thermocline depth, fluorescence, and abundances of total plankton and copepod nauplii. The feeding ecologies of the 21 taxa of fish larvae in this work were synthesized into qualitative and quantitative webs that illustrate the variable trophodynamic strategies of larvae in the SOF and the levels of community reliance upon zooplankton prey types. A review of 170 investigations on larval fish feeding revealed notable distinctions between high- and low-latitude regions, highlighting the substantial variability across environments in the role of larval fishes within the planktonic food web.

There has been substantial debate in recent years about the extent to which industrialized fishing has affected tunas and other large pelagic predator populations and altered the pelagic community. Variations in the type of data incorporated into assessments, statistical treatment of catch rate information, and different assessment methodologies have lead to diverging interpretations of stock levels and the sustainability of current large-scale industrialized fisheries. Simple nominal catch rates derived from Japanese longline catch and effort data paint a biased picture of the impact of industrialized fishing on the large pelagic tuna and billfish community, suggesting that abundance as of 2002 was only 10% of pre-1950 levels. Methods that correct for the spatial expansion, shift in distribution, and change in species targeting of the Japanese fleet, by averaging catch rates over spatial areas while imputing missing catch rate values, indicate a less severe decline with tuna and billfish stock reduced to an average of 50% of pre 1950 levels. For the majority of stocks, simple assessment methods indicate these relative abundance trends may still be biased and additional information sources are necessary to constrain assessments and evaluate the status of the stocks. With the incorporation of prior information on current fishing mortality rates and in some instances stock productivity, assessments indicate that a number of stocks are over-fished and experiencing over-fishing. Optimization models based on the same catch and effort data, aimed a redistributing fishing effort to maximize profits subject to fishing mortality constraints, suggest economic efficiencies can be gained in the long term if effort reductions are coupled with closed areas. Areas open to fishing should be placed where potential value and recruitments into the fishery are high. Fisheries are complex adaptive systems and it is not necessarily apparent how data resulting from fishing activities relate to the states of the assemblage of species captured. Careful consideration must be given to the nature of the sampling processes that give rise to these data. Without such consideration or alternative sources of information, inferences about impacts of fisheries on natural systems can be severely distorted.

Orientador: Fernando Fernandes Mendonça
Resumo: A atividade pesqueira desempenha um importante papel ambiental e socioeconômico, pois é fonte de renda e alimento para milhões de pessoas no mundo. Entretanto, falhas em sua gestão e lacunas nos dados biológicos para muitas espécies, tem resultado na sobreexplotação de seus estoques, o que pode impactar diversos ecossistemas marinhos. Neste contexto, os peixes-de-bico, grupo formado pelas famílias Xiphiidae e Istiophoridae, são considerados valiosos recursos pesqueiros, porém ainda não há consenso sobre o número e a validade das espécies da família Istiophoridae e também há incertezas sobre a avaliação atual de seus estoques. Sendo assim, o objetivo deste estudo é o de delimitar as espécies da família Istiophoridae e os estoques genéticos do agulhão-vela Istiophorus platypterus no Oceano Atlântico utilizando marcadores moleculares mitocondriais. Entre os resultados dos testes de delimitação de espécies, o número variou entre 6 e 12 táxons possíveis, dependendo do teste aplicado. Em relação a delimitação dos estoques genéticos de I. platypterus no Atlântico, assumindo-se apenas uma espécie no gênero Istiophorus, nossos resultados apontam a existência de alta diversidade genética, componde um único estoque genético no Atlântico (ΦST=0,01121, p=0,02438), apresentando um alto fluxo gênico. Porém, pela análise da rede de haplótipos e da inferência bayesiana observa-se a existência de diferentes linhagens mitocondriais simpátricas, que divergiram durante o Mioceno Superior e foram ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Fishing activity plays an important environmental and socio-economic role, as it is a source of income and food for millions of people worldwide. Although, shortcomings in management and gaps in biological data for many species resulted in the overexploitation of their stocks, which may impact several marine ecosystems. In this context, billfishes, a group compounded by the Xiphiidae and Istiophoridae families, are considered valuable fish resources, but there is still no consensus on the number and validity of the species of Istiophoridae family and there are also uncertainties about the current fisheries stocks assessments. Thus, the main objectives of this study are to delimit the species of the Istiophoridae family and the genetic stocks of the sailfish, Istiophorus platypterus, in the Atlantic Ocean using mitochondrial molecular markers. Among the species delimitation tests results, the number ranged from 6 to 12 possible taxa depending on the test applied. In order to determine the genetic stock of I. platypterus in the Atlantic Ocean, assuming only one species in the genus Istiophorus, our results point to the existence of high genetic diversity, comprising a single genetic stock in the Atlantic (ΦST = 0.01121, p = 0.02438), presenting a high gene flow. However, the analysis of the network of haplotypes and Bayesian inference shows the existence of different sympatric mitochondrial lines, which diverged during the Upper Miocene and were re-approximated, interrupting th... (Complete abstract click electronic access below)
Doutor

碩士
亞洲大學
保健營養生技學系碩士班
98
The five billfishes are the important economical fish in Taiwan. They are used in many kinds of products, including slices of meat (sashimi), fish minced products and dried fish floss. The meats and products have a relatively high market price in Taiwan. Therefore, some retail dealers misuse the other low-price fish meats instead of billfish meats in order to make a profit. In this study we used of a specific Real-time PCR amplification of a repetitive DNA element, for the quantification by billfishes, because of its simplicity, specificity, and sensitivity. In the beginning we amplified of cycochrome c oxidase I and 16S rRNA finished the complete of billfishes sequencing, and designed suitable primers of DNA quantitative method of Real-time PCR. In this study, we used five billfishes assays were developed around small (amplicons 150 base pairs) region of the mitochondrial cytochrome c oxidase I (COI) gene. The assay first was tested on specificity and sensitive of primers. We defined that the primers were applicable to the five billfish, so second we used the primers detect the limit of billfish concentration, the sensitivity was as following: Makaira nigricans: 10-5 ng, Kajikia audaxt: 10-5 ng, Istiophorus platypterus: 10-4 ng, Xiphias gladius: 10-3 ng and Istiompax indica: 10-5 ng. Third was test on different time of heated and sterilized ( 100℃ heating from 0 – 90 min, 121℃ heating from 0 – 90 min) to define the limit of five billfish. The results showed the heted of billfish meats limit detected time was > 60 min, and the sterilized detected limit time was >30 min. Forth the assay was tested on DNA extracted from raw and heat-treated mixtures of billfishes tissues in a matrix, and on DNA extracted from reference stuff samples.The mixture of billfish meats limit detected was <0.5% of billfish’s DNA concentration, and the related products of billfish limit detected was about <1%. Replicate standard curves of the threshold cycle (Ct) value (Y) vs Different percentages of billfish DNA (X) were analysed using sigama plot 10.0 software and a linear regression equation of the Ct value plotted against Different percentages of billfish’s DNA was calculated. Furthermore, applying above the method to quantitative of billfish, we collected 44 commerical samples of billfish related products from northern region, centeral region, southern region and eastern region. It was found that qutitative of billfish in dressed fish fried marlin product were 30.47% - 100%, fish ball were 14.52% - 93.45%, surimi made by marlin was 87.21%, tempura made by marlin was 74.94%, and marlin egg roll was 71.03%. Base on the results we concluded that Real-time PCR condition developed in our research was applicable to the quantitative analysis of detecting the marlin meat products.

碩士
國立臺灣大學
海洋研究所
103
Billfish is an important fishery resource all over the world, and is usually marketed as sashimi, filleted, fish floss and sauce. Most billfish products in Taiwan were only labeled with “billfish” in their ingredients. Therefore, species identification of the billfish products is necessary and will benefit the conservation and regulation of these fishery resourcs. In this study, we developed a real-time PCR approach to identify the six billfish species：Swordfish (Xiphias gladius), Sailfish (Istiophorus platypterus), Black marlin (Istiompax indica), Striped marlin (Kajikia audax), Blue marlin (Makaira nigricans) and Shortbill spearfish (Tetrapturus angustirostris). The whole system contained 14 primers, including 12 species-specific primers and two universal primers designed for discriminating the six billfish from non-billfish species. The 12 species-specific primers showed clear discrimination among the six billfish species, with ΔCt values of the target species ranging between -2.23 ~ 3.93 and the limit of detection is 0.4 ng/μL. In order to minimize the cost and time of whole identification system, we also tested the applicability of the multiplex qPCR by combining several species-specific primers in a single reaction to identify the species. The result showed that the six species can be identified according to the melting curve pattern and Tm values for X. gladius： Tm1 = 75.0 ± 0.0 °C, Tm2 = 83.5 ± 0.0 °C, I. platypterus：Tm1 = 75.2 ± 0.3 °C, Tm2 = 80.5 ± 0.2 °C, I. indica：Tm1 = 77.5 ± 0.0 °C, Tm2 = 80.5 ± 0.0 °C, K. audax：Tm = 80.5 ± 0.0 °C, M. nigricans：Tm1 = 76.0 ± 0.0 °C, Tm2 = 80.5 ± 0.0 °C, T. angustirostris：Tm = 77.0 ± 0.0 °C. An identification protocol for the six billfish species was established in this study. The methods is efficient, sensitive, and cheaper than other conventional methods, which will be helpful for fishery management and protecting the consumer’s rights.

博士
國立臺灣海洋大學
食品科學系
94
ABSTRACT The five billfishes are the important economical fish in Taiwan. They are used in many kinds of products, including slices of meat (sashimi), fish minced products and dried fish floss. The meats and products have a relatively high market price in Taiwan. Therefore, some retail dealers misuse the other low-price fish meats instead of billfish meats in order to make a profit. In our previous study, it was found that only 45.8% (11/24) commercial samples of billfish meat products were really made from the swordfish meat. The fish species of un-identified samples may be made from other marlin or cheaper fish. In this study, the varieties of the partial cytochrome b gene of different billfish species were compared, PCR-RFLP and multiplex PCR as molecular markers for phylogenetic relationship in the five species of billfish and related products were applied. The billfish species was further identified in the residue of several food poisonings in Taiwan. At beginning, the utility of primers (L-CYTBF & H-CYTBF) designed in our laboratory was successfully amplified for 348 bp of cytochrome b gene of five species of billfish in Taiwan. It could be differentiated after sequencing the 348 bp gene of these five species of billfish fish. In addition, using three-steps analysis by restriction enzymes, including Bsa JI, Cac 8I and Hap II, could distinguish these five species of billfish. In this study, we developed the multiplex PCR method to identificate the five billfish species. Primers ML-XG/MH-XG, ML-MN/MH-MN, ML-MI/MH-MI, ML-IP/MH-IP and ML-TA/MH-TA, were designed in different regions of mitochondrial DNA cytochrome b gene fragment after alignment of the available sequences in the genebank database. The primers generated specific fragment of 133, 201, 246, 305 and 348 bp length for five billfish species Xiphias gladius, Makaira nigricans, M. indica, Istiophorus platypterus and Tetrapturus audax, respectively. These methods are sensitive, rapidly and valid to detect fraudulent billfish products substituted from cheaper fish. In order to understand the application of above technique in processing products of billfish, the five billfish were frozen (-20℃ for 1 month), heat-treated (100℃ heating for 15 min; 121℃ heating for 15 min), and made into fish minced products and dried fish floss. It was found that DNA was degraded seriously by processes of dried fish floss and fragments were too short to be amplified by primers L-CYTBF & H-CYTBF. The cytochrome b gene of other products could be amplified and differentiated the species. We designed the other primers (L-CYTBD & H-CYTBF) which could amplify shorter target gene fragment to suit the seriously broken DNA from dried fish floss. Furthermore, applying above method to identify the fish species in the residues of histamine food poisonings in Pingtung and Taichung. It was found that the species of the poisoning billfish meats were identified as M. nigricans and X. gladius. Following this way, 72 commercial samples of fresh meats, fish minced products and dried fish floss were collected from Taipei, Taichung, Tainan and Kaohsiung of Taiwan. It was found that 20.8% (5/24), 33.3% (8/24), 45.8% (11/24) were detected not to be made from billfish meats by the above methods in fresh meats, fish minced products and dried fish floss, respectively. These results demonstrated the above DNA methods could identificate the original species of billfish products.

My study investigated the evolution of oxidative metabolism in fishes. While intense selection for, or against, non-synonymous point mutations in coding sequence drives the evolution of mitochondrial OXPHOS genes, genome-specific mechanisms such as gene duplication events can play major roles in the evolution of nuclear OXPHOS genes. My thesis focused on the mitochondrial enzyme cytochrome c oxidase (COX), principally in fish because of their evolutionary origins and functional diversity in terms of energy metabolism. In the first part of my thesis, I examined a highly aerobic group of fishes (billfishes and tunas) to study the evolution of mitochondrial COX genes. Though the study began as a structure-function analysis of COX, my approach changed when my preliminary results called into question the accepted phylogenetic relationships of my species of interest. We generated a robust multigene phylogeny of this group to interpret data in a phylogenetically informative context. Phylogenetic analyses in this group provided us with a framework to study the evolution of mitochondrial OXPHOS genes, but unexpectedly revealed that: 1) billfishes are only distantly related to tunas, and share greater evolutionary affinities with flatfishes (Pleuronectiformes) and jacks (Carangidae), and 2) regional endothermy has evolved in a non-scombroid suborder in teleosts. These results collectively imply that regional endothermy has evolved independently at least twice within teleost fish. The second part of my thesis explored the evolution of the nuclear COX subunits, focusing on their origins in fish. Isoform transcription profiles coupled with phylogenetic analyses for each subunit show that vertebrate isoforms arose from a combination of early whole-genome duplications in basal vertebrates or specific lineages (e.g. teleosts), and more recent single gene duplication events. While there is evidence for retained function of some COX orthologues across fishes and mammals, others appear to have diverged in function since their earlier radiation, possibly contributing novel evolutionary functions. Together these two studies provide insight into the evolutionary forces facilitating adaptive change in mitochondrial and nuclear OXPHOS genes.
Thesis (Master, Biology) -- Queen's University, 2009-09-11 11:00:12.562

碩士
國立臺灣大學
海洋研究所
101
Nitrogen and carbon stable isotopes were used to study the trophic dynamics of the billfishes and prey species in the waters off eastern Taiwan, and of the blue marlin in the Palau waters. White muscle samples were taken and frozen instantly at the Shinkang fish market of eastern Taiwan for the blue marlin, swordfish, black marlin and striped marlin captured in eastern Taiwan waters and the blue marlin captured in Paulau waters. Significant difference in δ15N was found among billfishes in the eastern Taiwan waters.The black marlin and swordfish have the highest δ15N, followed by the blue marlin, and the striped marlin has the lowest δ15N. The black marlin and blue marlin have the highestδ13C, followed by the swordfish and striped marlin.δ15N are influenced by body sizes and the foraging ability, while δ13C differences indicate the feeding ecology of different billfishes and their diverse uses of carbon. The δ15N difference between prey species and billfishes up to one trophic level indicates that the prey species collected in the study might be the important source of prey for billfishes in the eastern Taiwan waters. There was a significant difference in δ15N among seasons, the highest in the fall, followed by the summer, and the lowest in the spring and winter. However, no relationship was found between δ13C and seasons. The δ13C values were influenced by the primary productivity of the ocean. The highest primary productivity of the eastern Taiwan waters occurred in the fall, followed by the spring. The results indicated there are differences in the primary productivityamong seasons. However, no relationship was found in the δ13C among seasons. When the blue marlin moved between different oceans, they combined different stable isotope conditions. The long-distance movement of the blue marlin recorded a mixture of stable isotopes in the muscle tissues among different oceans. The δ15N of billfishes slightly increased with increasing size in the eastern Taiwan waters. However, no relationship was found betweenδ15N and body sizes in the Palau waters.This situation often occurs in the coastal and oceanic waters where migratory fishes feed. Because the prey composition of the ocean are similar, the stable isotope among predators have little difference. The δ15N of blue marlin in thePalau waters was higher than that in the eastern Taiwan waters. However, no difference was found in δ13C between thePalau waters and the eastern Taiwan waters. The stable isotope values in different oceans indicate different productivity, and in the study, the stable isotope values of top predators reveal the different primary productivity in different oceans.

碩士
國立高雄海洋科技大學
海洋環境工程研究所
98
This study is sponsored as a project by FA.COA (Fisheries Agency, Council of Agriculture, Executive Yuan, R. O. C.) during July and December in 2007, and cooperates with longline-fishing industry. In order to collect the temperature and depth in water layers and to record the gains of fish, there are minilogs on the branchlines of two longline -fishing boats in the Indian Ocean. By recording the relationship between temperatures, depth of different hooks, and the fish catch, this study discusses the inhabitable temperature-depth range , and the situation of vertical distribution of tunas and billfishes in the Indian Ocean. The result shows the gains of fish of Boat 1 and Boat 2 are Thunnus obesus(11652), Thunnus albacares(2155), Istiophorus platypterus(1167), Xiphias gladius(717) and others (1654) in ordered; the accumulated records of temperature (1092), depth (696). The CPUE of hooks of Thunnus obesus is much higher in deep layer, and the CPUE of Thunnus albacares, Istiophorus platypterus, and Xiphias gladius is higher in the surface layer. Besides, there is a trend the hooks increase as the temperature goes lower and the layer goes deeper. Due to the similarity of main fishing temperature and depth between two boats, this research analyzes them together. And the result shows the average temperature and depth for Thunnus obesus are 12.8~16.8℃ and 155.5~212.3m; Thunnus albacares, 14.9~20.5℃ and 115.1~185.5m；Istiophorus platypterus, 16.8~25.4℃ and 68.8~183.4m; Xiphias gladius, 11.7~23.5℃ and 130.0 ~ 187.0m.

碩士
國立臺灣海洋大學
環境生物與漁業科學學系
100
Abstract In this study, fishery indicators, including weigh frequency, central trend, maximum weight, the proportion of mature catch, catch frequency and mean catch per trip, were used to analyze the trend of population status for five billfishes caught in the waters off eastern Taiwan. For black marlin and sailfish, the results of this study indicated that the size indicators showed a relatively stable or increasing trend, the proportion of mature catch was high, mean catch per trip also gradually increased. Therefore, fishing exploitation might not lead to the decreases in the body size and the mature proportion for black marlin and sailfish in the waters off eastern Taiwan. Although size indicators and the proportion of mature catch of striped marlin increased in recent years, the catch frequency and mean catch per trip revealed obvious decreasing trend. Therefore, the population status of striped marlin in the waters off eastern Taiwan is needed to be further monitored. In recent years, size indicators of blue marlin and swordfish gradually decreased and the proportion of mature catch was also under relatively low level. Although the mean catch per trip and catch frequency slightly increased in recent years, most of indicators indicated that fishing exploitation might have led to the decreases in the body size and the mature proportion for blue marlin and swordfish in the waters off eastern Taiwan.