Made available in DSpace on 2015-03-26T13:46:34Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2071717 bytes, checksum: 2b2b2db684156dc843d94182ee1a1075 (MD5) Previous issue date: 2008-02-21 / Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Astyanax bimaculatus, oviparous fish, presents reproductive activity the year round and multiple spawning. It is important to know the reproductive biology to facilitate the reproductive management, minimize the expenses with the reproduction and develop new techniques that can to improve the reproduction with commercial and preservation interests. Studies demonstrate the importance of the growth hormone in the gametogenesis and gonadal ripening, as being an important factor of female reproduction. In this way, the present study histologically evaluates the Astyanax bimaculatus ovaries submitted to the induced spawning technique with a crude carp pituitary extract and the effect of the growth hormone in the ovarian recrudescence process after spawning. Respecting the different periods after induced spawning, the ovaries of fishes of the control group and the growth hormone treated group were analyzed using a light microscope, aiming to characterize the post-spawning ovarian morphology. From the biometric data obtained, the gonadossomatic index (GSI) and hepatossomatic index (HSI) values were calculated, and also the condition factor (K2), in the different collection schedules for the two groups under study. Around 60% of the females reacted satisfactorily to the crude carp pituitary extract injection. The extrusion of the oocytes occurred between 225 and 234 h-degrees after hypophysation. The oogenesis of A. bimaculatus seems to be similar to the majority of the fresh water teleosts. The analysis of the fragments of ovaries showed the constant presence of oocytes in the gonads during all pphases of development, post-ovulatory follicles, besides follicular atresia. Oocyte in primary growth were present in great number in the group-control, while oocytes in secondary growth were more numerous in the treated group. Post- ovulatory follicles were more numerous in the control group than in the treated group, and between 96th and 120th hours after spawning in both control group and treated group its detection became more difficult. The follicular atresia was observed in greater intensity in the treated group than in the control group. Significant differences (P<0.05) between the experimental were recorded at six and at 48th hours after spawning. Significant differences were not observed (P>0.05) for the eosinophyle counting inside the experimental groups. A greater quantity of eosinophyles was observed in the treated group, coinciding with the largest quantities of atretic follicles in this group. A significant difference (P<0.05) was noticed when the follicular atresia and eosinophyle values were associated and compared between the experimental groups. Due to a multiple spawning and not presenting abrupt variations in the size of the gonads, significant differences were not found (P>0.05) for the GSI in the different collecting periods and not even between the experimental groups. Statistical differences (P<0.05) for the HSI values were found between the experimental groups at the nine and 96 th hours postspawning. Higher values of HSI were registered in the group that received the hormone growth coinciding with the largest quantity of vitelogenesis oocyte observed in this group. Statistical differences were not found (P>0.05) for the condition factor (K2). / Astyanax bimaculatus, peixe ovíparo, apresenta atividade reprodutiva o ano todo e desova parcelada, características promissoras para seu cultivo. É importante conhecer a biologia reprodutiva para facilitar o manejo, minimizar os gastos com a reprodução e desenvolver novas técnicas para aprimorar a reprodução com interesse comercial e de preservação. Estudos demonstram a importância do hormônio de crescimento nos processos de gametogênese e maturação gonadal, sendo um importante modulador da reprodução da fêmea. O presente trabalho avalia histologicamente os ovários de lambaris submetidos à técnica de desova induzida com extrato bruto de hipófise de carpa, e o efeito do hormônio de crescimento no processo de recuperação ovariana após a desova. Após a desova induzida, ovários de peixes do grupo- controle e do grupo tratado com hormônio de crescimento foram analisados em microscopia de luz, visando caracterizar a morfologia ovariana pós-desova. A partir de dados biométricos obtidos, foram calculados os valores dos índices gonadossomático (IGS) e hepatossomático (IHS), e do fator de condição K2 nos diferentes horários de coleta para os grupos em estudo. Cerca de 60% das fêmeas hipofisadas responderam satisfatoriamente à injeção do extrato bruto de hipófise. A extrusão dos ovócitos ocorreu entre 225 a 234 horas-grau após hipofisação. A ovogenêse de A. bimaculatus parece ser similar à maioria dos teleósteos de água doce. A análise dos fragmentos de ovários demonstrou a presença constante de ovócitos em todas as etapas de desenvolvimento, folículos pós-ovulatórios, além de atresia folicular. Ovócitos em crescimento primário estiveram presentes em maior número no grupo-controle, enquanto ovócitos em crescimento secundário foram mais numerosos no grupo tratado. Folículos pós-ovulatórios foram mais numerosos no grupo-controle que no grupo tratado, e sua detecção tornou-se mais difícil entre 96 e 120 horas após a desova. A atresia foi observada em maior intensidade no grupo tratado que no grupo-controle. Diferenças significativas (P<0,05) na contagem de folículos atrésicos entre os grupos experimentais foram registradas as seis e às 48 horas pós-desova. Não foram constatadas diferenças significativas (P>0,05) para a contagem de eosinófilos dentro dos grupos experimentais. Observou-se maior quantidade de eosinófilos no grupo tratado, coincidindo com as maiores quantidades de folículos atrésicos nesse grupo. Diferença significativa (P<0,05) foi observada quando foram associados os valores de atresia e eosinófilos e comparados os mesmos entre os grupos experimentais. Por ser espécie de desova parcelada e não apresentar variação brusca no tamanho das gônadas, não foram encontradas diferenças significativas (P>0,05) para IGS nos diferentes horários de coleta e nem entre os grupos experimentais. Diferenças estatísticas (P<0,05) para os valores de IHS foram encontradas entre os grupos experimentais as nove e às 96 horas pós-desova. Valores mais altos de IHS registrados no grupo que recebeu a dose de hormônio de crescimento coincidem com a maior quantidade de ovócitos em vitelogênese observada nesse grupo. Não foram encontradas diferenças estatísticas (P>0,05) para o fator de condição K2.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-07-24T16:03:54Z No. of bitstreams: 1 2009 - Helaine dos Reis Flor.pdf: 3447034 bytes, checksum: 3861cf7664eb46a21add49a26a4479c2 (MD5) / Made available in DSpace on 2017-07-24T16:03:54Z (GMT). No. of bitstreams: 1 2009 - Helaine dos Reis Flor.pdf: 3447034 bytes, checksum: 3861cf7664eb46a21add49a26a4479c2 (MD5) Previous issue date: 2009-09-01 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior, CAPES, Brasil. / Farfantepenaeus brasiliensis is a native species also known as the pink shrimp, and is one of the most explored fishing resources of the Brazilian coastline. This study aims to evaluate the reproductive performance of the F. brasiliensis raised in captivity submitted to different diets and sex ratios. Wild broodstock were captured in the Ba?a de Sepetiba, near to the Restinga da Marambaia and were kept for 107 days in maturation tanks at the Esta??o de Biologia Marinha da Universidade Federal Rural do Rio de Janeiro (EBM-UFRRJ). After ten days of acclimatization, the animals were randomly assigned to 18 polyethylene tanks, 450L volume, with constant aeration, continuous filtered seawater exchange, feeding trays and pieces of PVC pipes to serve as shelter. Each tank stored six animals. The experimental design was completely randomized with six treatments and three repetitions for each. Three diet feeding protocols were evaluated: A- 25% commercial diet /75% fresh food; B- 50% commercial diet 50% fresh food e C- 75% commercial diet /25% fresh food and two sex rations (male:female) 1:1 and 1:2 were evaluated. Females shrimp were unilaterally eyestalk ablated and marked with alternate cuts on the uropods for individual identification. The number of spawns, fecundity and hatching rate were used as the criteria for evaluation of reproductive performance. The 1M:2F sex ratio and the B feeding protocol had the best results regarding reproductive performance related to number of eggs/female and total egg production. Treatments that used the C diet presented the best hatching rates, despite of the low number of spawns. Throughout the experiment moulting occurred, however the spawning stopped between the 81st and the 90th day, probably due to physiological stress. At the end of the experiment, the females presented low survival rate in every treatment, possibly due to handling stress occurred during the gonadal maturation checks. Overall results of the present study indicated that it is possible to reproduce the F. brasiliensis in captivity, in small tanks, showing satisfactory reproductive performance. Nevertheless, it is necessary to re-evaluate the animal handling, in order to decrease the mortality and optimize the performance in captivity. / Farfantepenaeus brasiliensis ? uma esp?cie nativa conhecida como camar?o-rosa, e um dos recursos pesqueiros mais freq?entes e explorados na costa brasileira. Este trabalho teve como objetivo avaliar o desempenho reprodutivo de F. brasiliensis em cativeiro submetidos a diferentes dietas e propor??es sexuais. Os reprodutores selvagens foram capturados na Ba?a de Sepetiba, pr?ximo ? Restinga da Marambaia e mantidos durante 107 dias em tanques de matura??o na Esta??o de Biologia Marinha da Universidade Federal Rural do Rio de Janeiro (EBM-UFRRJ). Ap?s dez dias de aclimata??o, os animais foram distribu?dos aleatoriamente em 18 tanques de polietileno com volume ?til de 450L, com aera??o constante, fluxo cont?nuo de ?gua do mar filtrado, bandejas de alimenta??o e peda?os de canos de PVC para servir de abrigo para os animais. Em cada tanque foram colocados 6 animais. O delineamento experimental foi inteiramente casualizado com seis tratamentos e tr?s repeti??es cada. Foram avaliadas tr?s dietas alimentares: A-25% ra??o/75% alimento fresco; B-50% ra??o/50% alimento fresco e C-75% ra??o/25% alimento fresco e duas propor??es sexuais (macho:f?mea) de 1:1 e 1:2.Todas as f?meas foram abladas e marcadas com cortes alternados nos ur?podos para identifica??o individual. A avalia??o do desempenho reprodutivo foi realizada atrav?s do n?mero de desovas, fecundidade e taxa de eclos?o de cada tratamento. A propor??o sexual 1M:2F e a dieta B apresentaram os melhores resultados de desempenho reprodutivo em rela??o ao no de desovas e fecundidade. Os tratamentos que receberam a dieta C foram os que apresentaram melhor taxa de eclos?o, apesar do baixo n?mero de desovas. Ocorreram mudas durante todo per?odo experimental, por?m a ocorr?ncia das desovas cessou entre 81o e 90o dia de experimento, provavelmente por desgaste fisiol?gico. Ao final do experimento, as f?meas apresentaram alta mortalidade em todos os tratamentos, possivelmente devido ao estresse causado pelo manuseio di?rio para vistoria da matura??o das g?nadas. Os resultados obtidos no presente estudo constataram a possibilidade de F. brasiliensis reproduzir em cativeiro em tanques pequenos, apresentando desempenho reprodutivo satisfat?rio. Por?m ? necess?rio reavaliar o manejo, para diminuir a mortalidade e melhorar a efici?ncia de c?pula, para otimizar o desempenho em cativeiro.

Restoration efforts are being implemented in many of the world’s coral reefs due to damages from anthropogenic sources such as ship groundings and anchor damage. One restoration technique involves attempts to save dislodged and fragmented coral colonies by transplanting them back to damage sites. Research has shown that survivorship and growth of transplanted colonies is comparable to that of natural, control colonies. What remains unknown is to what extent transplantation affects the ecological success and reproduction of dislodged and fragmented coral colonies. The purpose of this study was twofold. Reproduction and spawning information is sparse for S. intersepta and Solenastrea bournoni, so the first purpose was to describe gamete development of these two species and assess correlations between environmental dynamics and spawning of each species. Tissue samples were collected throughout Broward County, Florida and processed for histological examination. Gametes were counted, and development was assessed. For S. intersepta and S. bournoni, late stage oocyte abundance was compared with environmental factors of mean daily water temperatures at depth, lunar phase, semidiurnal tides and solar insolation for correlative evidence to predict future spawning events. Findings indicated that both S. bournoni and S. intersepta are gonochoric broadcast spawners. Solenastrea bournoni spawns annually after the full moon in September when sea temperatures are at a maximum. Stephanocoenia intersepta spawns annually after the full moon of August or September, depending on the timing of the full moon. The second purpose was to determine if previously transplanted Porites astreoides, Montastraea cavernosa, Siderastrea siderea and Stephanocoenia intersepta corals produce gametes and spawn similarly to naturally occurring colonies and to address the issue of transplantation as a suitable resource management tool to aid in reef recovery for future coral generations. Results indicated no significant difference in fecundity between transplants and controls of M. cavernosa, S. siderea or S. intersepta. A significant difference was found in fecundity between P. astreoides transplants and controls, but it is thought that it is due to a difference in depth of collected samples. Overall, this study shows that transplantation of coral colonies after damage and fragmentation events does not have adverse effects on the long-term fecundity of coral colonies.

Abstract Dam building for hydropower production, dredging for log floating and drainage of peatlands have massively affected migrating salmonid populations in Finland. Increased sedimentation and changes in hydraulic conditions have destroyed the majority of spawning and rearing habitats in freshwater brooks and dam building has stopped migration upstream at river mouths. This thesis examines the current state of drained forest brooks, possibilities for restoration and methods to assist migration in rivers used for hydropower. Drainage down to the mineral soil has caused massive erosion and sedimentation in headwater brooks. The surface layer of a sand bed is constantly moving, preventing vegetation growth, while shortcuts created during drainage increase flow velocity and reduce retention time. The cross-sectional and longitudinal profiles become homogeneous and biodiversity is severely reduced. A simple wooden brook restoration structure was developed in laboratory experiments. Fish migration problems past a hydropower dam and reproduction possibilities offered by a natural-like bypass channel were studied in the river Oulujoki, the mouth of which was blocked by a hydropower dam in the late 1940s. Public pressure for remedial structures has grown since then and was given a boost after a fishway was opened at Merikoski, in the river mouth, in 2003. This thesis examined the next dam upstream, Montta at Muhos, which was studied separately as a partial and sole natural-like bypass. A natural-like bypass can offer stable conditions for spawning and rearing and can be designed precisely, through water flow and habitat modelling, to match desired conditions. The most important section in a fishway is ultimately the entrance. Fishway discharge is often merely a fraction of whole river discharge and the attractivity of the entrance can be increased by pumping additional discharge to the lowest part of the fishway. The hydraulics of a twin-slot vertical slot fishway were studied here by laboratory flume testing and 2D water flow modelling. Water flow and habitat modelling proved to be good tools in designing partly natural-like bypasses. However, fish behaviour should be closely monitored in any natural-like fishways already built, in order to verify the results of habitat modelling. / Tiivistelmä Jokien patoaminen vesivoiman tuotantoon, ruoppaaminen puunuiton helpottamiseksi sekä latvapurojen ojitukset metsän kasvun edistämiseksi ovat voimakkaasti vaikuttaneet vaeltavien lohikalakantojen vaellus- ja lisääntymismahdollisuuksiin. Muuttuneet hydrauliset olosuhteet ja lisääntynyt sedimentaatio ovat tuhonneet lohikalojen lisääntymisalueet ja patoaminen on katkaissut ylösvaelluksen lisääntymispaikoille. Väitöstyö koostuu viidestä artikkelista, joissa esitellään uusia menetelmiä ja ratkaisuja lohikalojen vaelluksen ja lisääntymisen ennallistamiseksi. Kaksi artikkelia keskittyy ojituksesta kärsivien latvapurojen nykytilaan, kunnostusmahdollisuuksiin sekä kunnostusrakenteen kehittämiseen. Paikoin ojituksen seurauksena on ollut massiivinen mineraalimaan eroosio ja hienon hiekan sedimentoituminen puroihin. Puroihin on kertynyt paksuja hiekkakerroksia, joiden pintakerros on jatkuvassa liikkeessä. Pintakerroksen jatkuva liike estää kasvillisuuden kasvamisen. Osittain ojitus on myös oikaissut puroja, jolloin virtausnopeudet ovat kasvaneet ja veden viipymä lyhentynyt. Purojen pituus- ja poikkileikkauksen vaihtelu ja biodiversiteetti ovat on vähentyneet huomattavasti. Laboratoriokokeissa kehitettiin yksinkertainen puusta rakennettava kunnostusrakenne hiekoittuneiden purojen kunnostamiseksi. Kolme artikkelia käsittelee Oulujokea, kalateiden suunnittelua ja kalatierakenteita. Vuonna 2003 rakennettu Merikosken kalatie kasvatti paineita kalatierakentamiseen Oulujoen muille voimalaitoksille. Erityisesti väitöstyö keskittyi Montan voimalaitoksen ohitukseen suunniteltuun kalatiehen, jota tutkittiin virtausmallinnuksen avulla kokonaan ja osittain luonnonmukaisena ohitusuomana. Luonnonmukainen ohitusuoma voidaan suunnitella toimimaan kutukanavan tyyppisenä uomana, jonka tarkoitus on tarjota vakaat virtausolosuhteet lohikalojen lisääntymistä varten. Virtaus- ja habitaattimallinnuksen avulla uoma voidaan suunnitella tarkasti haluttujen virtausolosuhteiden mukaisesti. Kalatien toimivuuden kannalta tärkeintä on että kalat löytävät kalatien sisäänkäynnin. Kalatien virtaama on usein vain murto-osa koko joen virtaamasta, joten sisäänkäynnin houkuttavuutta voidaan lisätä lisävettä pumppaamalla. Kaksirakoisen pystyrakokalatien hydrauliikkaa tutkittiin sekä laboratorio- että virtausmallilla.

Several studies suggest the environment influences chokka squid catches which are mostly based on the successful formation of inshore spawning aggregations. None of the evidence, however, is direct observation. Acoustic telemetry offers a means to determine the response of spawners to changes in the environment and insight into the behaviour of spawning squid. A hexagonal array of VR2 receivers deployed 500 m apart was deemed to be ideal to monitor the movement patterns of squid on the spawning sites. In isothermic conditions, an area up to 1.28 km2 could be monitored as there was an approximate 50 m overlap in individual VR2 receiver range. In thermocline conditions however, “acoustic dead zones” as wide as 350 m may have existed between VR2 receivers, limiting the performance of this configuration. Similarly benthic turbidity events would also decrease detection range and limit performance. A hexagonal array of VR2 receivers was moored in Kromme Bay on and around active spawning aggregations during the squid fishery closed seasons of November 2003, 2004, 2005 and 2006. Squid were caught on jigs and tagged with V9 acoustic pressure telemetry transmitters. A total of 45 animals were tagged. Presence-absence analysis identified three general behaviours: (1) arrival at dawn and departure after dusk, (2) a continuous and uninterrupted presence for a number of days and (3) presence interrupted by frequent but short periods of absence. Overall, the data suggests frequent migrations between spawning aggregations and offshore feeding grounds. The pressure sensor data showed both males and females stayed persistently near the seabed during the day, but at night, this pattern was broken with common activity higher up in the water column. The squid did not remain exclusively in the water column and regularly made excursions to the seabed. CTD and temperature data indicated the intrusion of a cold bottom layer due to upwelling at the monitored spawning sites on a number of occasions. The formation of spawning aggregations appears to be triggered by upwelling events and spawning behaviour, once initiated, disrupted by upwelling events with a rapid onset, possibly due to an inability to adapt physiologically over such a short time period.

For many native, imperiled salmonid species, the prioritization of recovery and conservation efforts hinges upon the identification of a species most limiting life stage. The early life-history stage can be a limiting life stage for fish, and given the importance of the reproductive stage to overall persistence, there is a need to better understand the spawning ecology and early life history of many salmonids. The Logan River, in northern Utah, contains one of the largest metapopulations of imperiled Bonneville cutthroat trout (BCT) throughout the Bonneville Basin. Little research has evaluated the temporal and spatial distribution of BCT spawning nor quantified their early life-history survival. In the summer of 2008, I documented the spawning ecology of BCT and quantified their early life-history survival via egg-to-fry survival field experiments in four tributaries to the Logan River. I observed considerable variability in the timing, magnitude, and duration of spawning between study streams, in part as a function of a variable, multi-peaked hydrograph. I also conducted egg-to-fry survival experiments using incubation boxes and hatchery-fertilized, eyed cutthroat embryos and installed these boxes throughout my study streams. I found that survival was extremely variable within and among my study streams. For example, the variation I observed in survival appeared to be a function of fine sediment loads. Lastly, I observed that in the Logan River the timing of greatest intensity of both stream side and in-stream anthropogenic activities (e.g., livestock grazing, horseback riding) overlaps directly with the spawning and early life stages of BCT. Using my estimates of early survival, I revised a four-stage matrix population model for BCT in order to evaluate the hypothetical effects of anthropogenic impact on rearing areas. I determined that population growth rates are sensitive to perturbation at the egg-to-fry and fry to age-1 stages, and if even a small number of redds are destroyed through habitat degradation, a high degree of immigration of reproductively mature BCT is required to maintain the near-term persistence of this population. Future conservation efforts for BCT should be prioritized to protect areas where land-use activities are high during the sensitive spawning and early life-stage periods.

My aim in this study is to identify Late Archaic persistent places—places of continued importance throughout the long-term occupation of a region—within the lower Grand River Area of what is now southern Ontario. I accomplish this through the use of kernel density estimation applied to datasets containing the locations of Late Archaic (4000-2800 RCYBP) sites within this study area which were discovered through cultural resource management (CRM) survey and excavation. Areas identified as persistent places were investigated with regard to landscape features and environmental affordances that could have structured their consistent re-use throughout the Late Archaic, with particular attention paid to the hypothesis that persistent places may have developed around the riverine spawning grounds of spring-spawning fish. Two places with particularly intense concentrations of diagnostic materials dating to successive periods of the Late Archaic were identified: one surrounding Seneca Creek near Caledonia, and one near D’Aubigny Creek south of Brantford. The results show that the persistent use of these places would likely have been structured by the presence of landscape features which would have made these areas particularly rich in many different seasonal resources during the Late Archaic. Perhaps most significantly, both areas are located in close proximity to areas identified as walleye spawning grounds. The contributions of this thesis include the synthesis of the results of many years of CRM survey of the Grand River Area, evidence for the existence of Late Archaic riverine fishing sites related to the spawning runs of walleye, and an improved understanding of Late Archaic subsistence-settlement systems. / Thesis / Master of Arts (MA) / Lay Abstract: My aim in this study is to identify persistent places—places of continued importance throughout the long-term occupation of a region—within the lower Grand River Area of what is now southern Ontario during a period known as the Late Archaic (ca. 2500 B.C.- ca. 1000 B.C). This was accomplished using GIS spatial analysis of data produced through commercial archaeological assessments. As a result of this analysis, I identified two persistent places within the study area: one near D’Aubigny Creek south of Brantford, and one surrounding Seneca Creek near Caledonia. I also investigated the environments surrounding these places to determine what may have made them continuously appealing for over a millennium. Both areas were found to contain environmental features that would have likely made them particularly resource-rich and appealing to hunter-gatherers. One of the most important findings was that both areas are in close proximity to walleye spawning grounds.

Studies were conducted with the Asiatic clam, Corbicula fluminea, that examined seasonal periodicities in spawning, body condition, and percent tissue water content. In addition, responses of adults to brief (24 hr) and extended (30 d) periods of exposure to toxicants were investigated. These studies addressed the valve closure behavioral response by adults exposed to chlorine, cadmium, and zinc; the effects of these pollutants and temperature on the levels of metal binding protein in adults; and the efficacy of halogens ( chlorine and bromine) in providing acceptable levels of Asiatic clam biofouling control. Spawning periodicity of C. fluminea was monitored weekly for 8 months in 1984. Observations revealed that spawning occurred on three distinct occasions with peaks in release of veligers in June, August, and October. Percent tissue water content and body condition were monitored monthly in 1985. Significant differences in these parameters were observed among certain months and among size classes. Tissue water content and body condition in the largest individuals were inversely related. Periods of activity (valves parted) and quiescence (valves closed) were determined in the absence and presence of toxicants by continuously monitoring valve movement patterns. Data indicate that the duration of activity periods and toxicant exposure concentration are inversely related. Application of these observations to efforts to control Asiatic clam fouling in industrial water lines resulted in a reduction in the total levels of molluscicide required. Exposure of clams to low levels of chlorine (0. 25 mg/L total residual chlorine) induced valve closure that resulted in weakened clams after two weeks that were more susceptible to increased levels of chlorine. The levels of a metallothionein-like metal binding protein (MBP) in tissues of Q. fluminea following exposure to metal and non-metal stressors were also assessed. In general, exposure to dissolved cadmium resulted in significantly greater levels of MBP than either dissolved zinc, chlorine, or temperature extremes (4°, 30°C). Analysis of individual organ groups demonstrated an inverse relationship between sites of MBP synthesis ( gills, mantle, and adductor muscles versus visceral mass) and mode of exposure to cadmium (dissolved versus food associated). / Ph. D.

The dusky grouper Epinephelus marginatus (Lowe 1834), is a protogynous sequential hermaphrodite and is considered to be one of the most important fish species in the Mediterranean Sea. It is a K-strategist, being slow growing and late maturing, and this, coupled with its reproductive biology and relatively sedentary behaviour, has made it extremely sensitive to overexploitation, leading it to be classified by the IUCN as an endangered fish species. Wild dusky grouper have suffered from disease outbreaks in the past decade, leading to mass mortalities across the Mediterranean Sea, including Libyan coastal waters. These mortalities have mostly been attributed to Nodavirus infections. In Europe and Brazil, efforts are in place to culture this fish for commercial grow-out and stock enhancement programmes. In Libya, the dusky grouper is consumed regularly and is considered a prime-eating fish. Its importance for the Libyan internal market, as well as its potential for export, makes it an ideal candidate for future Libyan aquaculture activities. Given the scarce literature regarding the dusky grouper in Libya, this study aimed first to assess dusky grouper fisheries, spawning seasons and to identify the main threats that the fishing sector poses for wild stocks. Second this study aimed to determine the health status of wild dusky grouper offered at a local fish market in the capital Tripoli, in order to identify pathogens, pathologies or other health issues that might pose a hazard to cultured populations but also to remaining wild dusky grouper stocks. To achieve these aims, twelve field surveys spanning the period of 2013-2015 were conducted. From these surveys, it was established that the dusky grouper is captured throughout the year, including the spawning season. Fish sizes offered for sale ranged between 20-92 cm total length (TL), with the fish being sold from local fishing grounds around Tripoli, but also from as far as Benghazi, 1300 km to the east of Tripoli. The dusky grouper is principally caught in artisanal fisheries and by spearfishing, with approximately 300 spear-fishermen serving one particular fish market in Tripoli that was a focus in this study, and with dusky grouper being one of their main targets. Over the period of the survey, 267 landed dusky grouper were inspected for visible lesions prior to sampling. A total of 50 dusky grouper with sizes ranging from 27- 66 cm TL including the gonads from a further five fish measuring 66-92 cm TL that were sampled separately and examined to assess the stage of sexual maturity and to look for the presence of parasitic infections mainly affecting the gills, skin and gonads. The spawning season was found to extend from May to early September, with females ranging between 39-68 cm TL, males measuring 57-92 cm TL, and transient fish measuring 58-68 cm TL. From otolith readings of 8 fish, the youngest fish was a 3 year old juvenile of 28 cm TL and the oldest was an 8-9 year old 56 cm TL female. Whilst the highest prevalence of parasitic infection was found to be monogenean infection of the gills, with 100% prevalence, followed by gnathiid isopods infecting the oral cavity with 92% prevalence, it was the nematode Philometra sp. infecting post-spawning ovaries at 52% prevalence, that gave the highest apparent pathological impact. Necrosis potentially attributed to Philometra sp. in one particular ovary, was at a level likely to have caused complete parasitic castration, while others showed varying levels of probable functional reduction. The pathologies described need further investigation, especially in relation to possible synergies between Philometra sp. and bacteria in causing the necrosis. From the 267 inspected dusky grouper, 55 fish ranging in size from 42-92 cm TL were observed to be affected by external skin lesions of unknown aetiology. Twenty-six of these fish were sampled, having lesions at various stages of severity, and 5 further unaffected fish were used for histological assessment of the skin as negative controls. Histopathologically, the lesions comprised a multifocal, unilateral or bilateral dermatitis, involving the epidermis, superficial dermis and scale pockets, and sometimes, in severe cases, the hypodermis. Severe lesions had marked epidermal spongiosis progressing to ulceration. Healing was observed in some fish. Bacteria and fungi could be isolated from severe lesions, although they were not seen histopathologically in early-stage lesions. By contrast, metazoan parasite eggs were observed in the dermis and epidermis of some fish with mild and moderate dermatitis. Unidentified gravid digenean trematodes, carrying similar eggs, were also seen within the blood vessels of the deep and superficial dermis. The newly described condition was termed dusky grouper dermatitis (DGD). DGD’s geographical distribution along the Libyan coastline was investigated using a novel application of the social media network Facebook. Using Facebook, it was possible to document skin lesions of dusky grouper in Libyan waters from images attached to the entries of spear-fishermen. Thirty two Facebook accounts and 8 Facebook groups posting from 23 Libyan coastal cities provided a retrospective observational dataset comprising a total of 382 images of dusky grouper caught by spearfishing from December 2011-December 2015. Skin lesions were observable on 57 / 362 fish, for which images were of sufficient quality for analysis, giving a minimal prevalence for lesions of 15.75%. Only dusky grouper exceeding an estimated 40 cm total length exhibited lesions. The ability to collect useful data about the occurrence and geographical distribution of pathological conditions affecting wild fish using social media networks, demonstrates their potential utility as a tool to support epidemiological studies and monitor the health of populations of aquatic animals. The gravid digenean trematode described from mild lesions of five fish was identified using reconstruction through histological sectioning as belonging to the Family Aporocotylidae Odhner, 1912. This is the first description of a blood fluke from the dusky grouper, as well as from dermal blood vessels. The parasite was relatively long; the longest section of the parasite that could be measured was 1500 µm and 20-80 µm in width, while the total length of the parasite was estimated at 1500-2000 µm. Minute tegumental spines, possibly covering only a few parts of the parasite, were seen from some cross-sections. The parasite had one post-testicular ovary, which might overlap the testis, a pre-ovarian ascending uterus, and a post-ovarian descending uterus. It also possessed an oesophagus surrounded by oesophageal glandular cells and a pre-ovarian and pre-testicular extension of the vitelline cells, mostly at the level of the ascending uterus. The parasite was observed to be intra-vascular, the uterine lumen varies in size to accommodate between 1-7 eggs. The uterine eggs were embryonated and observed to span several stages of maturation. Eggs were also found in the dermal blood vessels, in the dermis, and in the epidermis, with the latter appearing to provide a potential route of egress of eggs into the environment. The extra-uterine eggs were 23.5 to 37.52 µm long and contained a ciliated miracidium. The eggs seemed to elicit a mixed inflammatory reaction, with degranulation of eosinophilic granular cells attached to the external surface of some of the eggs within the blood vessels but also the dermis. From observations made in the current study, this parasite appears to be a new species, most closely allied to none of the currently described Aporocotylidae genera. / In summary, the present study has demonstrated that the dusky grouper is extensively fished in Libya without discrimination to sizes and season, by both artisanal and spearfishing, with the latter as one of the main fishing methods, posing treats to the spawning potential and conservation of dusky grouper in Libya. The philometrid infecting the ovaries has a potential to reduce fecundity or to result in parasitic castration of wild broodstock. Gill-infecting monogeneans might represent a hazard for all stages of dusky grouper production. Dusky grouper dermatitis is a skin lesion, although there are no indications that infections may result in mortalities. Under culture conditions, however, this might change due to increase bacterial loads, which might lead to secondary bacterial infection. The presence of skin lesions would undoubtedly reduce the market value of whole fish. These findings are important for existing wild stocks, and for future plans regarding the aquaculture of dusky grouper. Future studies need to focus on the pathology of DGD, describing the disease process and aetiology using laboratory techniques such as TEM and virology as well as using morphology and molecular-based tools to describe the blood fluke and to determine their potential role in the initiation the disease. The novel approach to disease surveillance using social media Facebook posts could be further expanded by attracting citizen scientists, for future research assessing disease in wild fish, for sightings of mortality events and/or the appearance of disease outbreaks, or, for mapping marine mammal stranding’s and/or turtle nesting activity.

The clown loach Chromobotia macracanthus, is a well known species in ornamental fish circuits although the knowledge about it in its wild environment today is limited. The outtake of 50 million juveniles every year may drive the population into a collapse and it might be necessary to breed clown loaches in captivity to lower the pressure in wild stocks. This has not yet been accomplished without hormone treatment. The aim of the present study is to find out if it is possible for C. macracanthus to prepare for spawning in captivity without the use of hormones. The study was set up according to documentation about the wild conditions simulating the migration prior to spawning from greater rivers and swamps to smaller streams upriver. Although the experiment did not result in spawning it is believed that egg production took place according to criteria for identifying sexually mature fish ready to spawn. If so it would have resulted in the fish retaining or reabsorbing the eggs since they were not laid. A surprising result which tells us it would not be unusual with egg production in C. macracanthus in aquariums around the world.