Thematische Bibliographien / Demersal specie

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Auswahl der wissenschaftlichen Literatur zum Thema „Demersal specie“

Autor: Grafiati
Veröffentlicht am 1. April 2023

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Zeitschriftenartikel zum Thema "Demersal specie"

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Miotto, Maiara Larissa, Barbara Maichak de Carvalho, Henry Louis Spach und Edison Barbieri. „ICTIOFAUNA DEMERSAL NA ALIMENTAÇÃO DO GAIVOTÃO (LARUS DOMINICANUS) EM UM AMBIENTE SUBTROPICAL“. Ornitología Neotropical 28 (12.04.2017): 27–36. http://dx.doi.org/10.58843/ornneo.v28i0.108.

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RESUMO ∙ Informações sobre a dieta de aves marinhas são de grande importância para o entendimento entre as aves e seu ambiente. Sabe‐se que o Gaivotão (Larus dominicanus) costuma forragear descartes de pesca, e que na área amostrada estes descartes são abundantes na modalidade de arrasto, com grande volume de peixes demersais. Foi analisado o hábito alimentar da L. dominicanus no estado do Paraná, Brasil. Os itens alimentares dos pellets foram identificados a fim de demonstrar a importância dos peixes demersais na dieta desta espécie. Os pellets foram amostrados entre agosto de 2011 e julho de 2012 no balneário de Barrancos. Baseado na identificação dos otólitos encontrados nos pellets, foi retrocalculado o comprimento e a massa dos peixes. Nos 120 pellets coletados, foram identificados 228 peixes, de 14 espécies e 3 famílias, destaque para a família Sciaenidae com 11 espécies. Cathorops spixii, Larimus breviceps, Paralonchurus brasiliensis e Stellifer rastrifer foram mais frequentes. Nas análises sazonais L. breviceps, Micropogonias furnieri, P. brasiliensis e S. rastrifer foram encontrados na dieta de L. dominicanus em todas as estações. A análise canônica demonstrou diferenças sazonais significativas na abundância, massa e comprimento dos teleósteos identificados na dieta de L. dominicanus. Este estudo demonstrou a frequente ocorrência de peixes demersais na dieta de L. dominicanus, sugerindo que este tipo de descarte de pesca é uma importante fonte de alimento para as populações locais de esta espécie.ABSTRACT ∙ Demersal fish in the diet of the Kelp Gull (Larus dominicanus) in a subtropical environment Information on the diet of sea birds is of great importance for the understanding between birds and their environment. It is known that the Kelp Gull (Larus dominicanus) is used to forage discards, and that in the area sampled these discards are abundant in trawling mode, with a large volume of demersal fish. The food habit of L. dominicanus was analyzed in the State of Paraná, Brazil. The food items of the pellets were identified in order to demonstrate the importance of demersal fish in the diet of this species. The pellets were sampled between August 2011 and July 2012 on the seaside of Barrancos. Based on the identification of the otoliths found in the pellets, length and mass of fishes were recalculated. In the 120 pellets collected, 228 fishes from 14 species and 3 families were identified, with emphasis on the Sciaenidae family with 11 species. Cathorops spixii, Larimus breviceps, Paralonchurus brasiliensis, and Stellifer rastrifer were most frequent. In the seasonal analyses, L. breviceps, Micropogonias furnieri, P. brasiliensis, and S. rastrifer were found in the diet of L. dominicanus in all seasons. The canonical analysis showed significant seasonal differences in abundance, mass, and length of the teleosts identified in the diet of L. dominicanus. This study demonstrated the frequent occurrence of demersal fish in the diet of L. dominicanus, suggesting that discards are an important source of food for the local populations of this species.
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Murano, Masaaki, und John Mauchline. „DEEP-SEA MYSIDS FROM THE NORTH ATLANTIC OCEAN WITH DESCRIPTION OF FOUR NEW SPECIES“. Crustaceana 72, Nr. 3 (1999): 273–95. http://dx.doi.org/10.1163/156854099503366.

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AbstractSeven species of Erythropini from the northeast Atlantic and one from the northwest Atlantic are dealt with. Four are described as new species, and three are new to science but remain unnamed because of mutilated condition. A known species Katerythrops oceanae, is described for the first time for the male pleopods and a revision of the diagnosis of the genus is presented. Five are pelagic species while three were obtained from the stomach contents of demersal fishes. Huit especes d'Erythropini de l'Atlantique sont traitees, dont sept du nord-est et une du nordouest de cet ocean. Quatre sont decrites comme nouvelles et trois sont nouvelle pour la science, mais non nommees en raison de leur condition mutilee. Les pleopodes males d'un espece connue, Katerythrops oceanae, sont decrits pour la premiere fois et la diagnose du genre est revisee. Cinq especes sont pelagiques et trois proviennent de contenus stomacaux de poissons demersaux.
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Prince, Jeremy D. „Ecosystem of the South East Fishery (Australia), and fisher lore“. Marine and Freshwater Research 52, Nr. 4 (2001): 431. http://dx.doi.org/10.1071/mf00042.

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A description of the marine ecosystem that sustains fisheries production around south-eastern Australia is based on a synthesis of fisher lore of the demersal trawling sector, a review of the literature and a decade of the author’s field observations. A wide range of species are fished demersally in the South East Fishery (SEF). Until recently, managers and researchers have often implicitly assumed that many of these demersally caught species were neritic and lived in close association with the seabed. In contrast, fisher lore emphasizes the pelagic and oceanic nature of the commercial resource together with its environmentally forced variability. This paper substantially supports the views of the fishers. Up to 90%of the primary production of the SEF ecosystem may be garnered by fish foraging through extensive, but relatively sparse, oceanic phytoplankton and gelatinous zooplankton communities. Sporadically, climatic conditions cause oceanographic features to interact with shelf-break features and create ephemeral hotspots of primary production along the shelf break. Fish of the SEF take advantage of these productivity events to aggregate for feeding and breeding and their episodes of aggregation and dispersion cause the large seasonal variations in catchability observed with the shelf-break species. Implications for ecosystem management are briefly discussed.
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Suprapto, Suprapto. „INDEKS KEANEKARAGAMAN JENIS IKAN DEMERSAL DI PERAIRAN TARAKAN“. BAWAL Widya Riset Perikanan Tangkap 6, Nr. 1 (31.12.2015): 47. http://dx.doi.org/10.15578/bawal.6.1.2014.47-53.

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Perairan Tarakan termasuk daerah penangkapan sumber daya ikan demersal dan udang cukup potensial di KalimantanUtara. Tingginya tingkat eksploitasi ikan demersal dengan menggunakan trawlmenyebabkan keragaman jenisnya rendah. Penelitian ikan demersal dilakukan di perairan Tarakan pada bulanMei,Agustus dan Nopember 2012. Tujuan penelitian adalah untuk memperoleh indeks keanekaragaman jenis ikan demersal. Data spesies ikan demersal dikumpulkan dari hasil tangkapan jaring trawl yang dioperasikan oleh kapal motor 20GT dengan metode sapuan area. Hasil penelitian menunjukkan bahwa jumlah taksa ikan demersal sebanyak 86 spesies yang tergolong kedalam45 famili. Komposisi jenis hasil tangkapan trawl didominasi oleh famili Leiognathidae (ikan petek), Sciaenidae (ikan gulama), Harpadontidae (ikan nomei),Apogonidae (ikan serinding) danMullidae (ikan bijinangka). Status keanekaragaman jenis termasuk dalamkategori sedang dengan indeks “Shanon-Wiener” (H’)berkisar antara 1,7-2,5 sedangkan indeks kekayaan “Margalef” (R1 ) berkisar antara 7-8. Penyebaran spesies ikan demersal bersifat sedang dengan indeks kemerataan jenis (E) rata-rata sebesra 0,5.Kelimpahan ikan demersal tidak ada yang dominan, ditunjukkan oleh nilai indeks kemerataan jenis “Pielou” (E) rata-rata sebesar 0,4.Tarakan and adjacent waters is one of potentially fishing ground of demersal fish resources in north Kalimantan. High exploitation by trawler tend to decreased of biodiversity of demersal fish in this area. Research has been conducted in the waters of Tarakan duringMay, August and November 2012. The aim of this research is to get species diversity indices of demersal fish, which is expected to be useful as one of the data capacity for sustainable fisheries management policy. Data obtained by using trawl fishing gear with a sweept area method.The results showed that demersal fish species richness 86 species, belonging to 45 families. Dominant family are Leiognathidae, Sciaenidae, Harpadontidae, Apogonidae andMullidae. Result of analysis indicate that species diversity in Tarakan waters in the medium category. Status of biodiversity consist of: range value diversityindices “Shanon-Wiener” (H’) was 1.7 to 2.5; species richness indices of “Margalef” (R1 ) are between 7-8; evenness indices of “Pielou” (E 1) was 0,5 and dominant indices “Pielou” (E) an average of 0.4.
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Olaso, Ignacio, Francisco Sánchez, Cristina Rodríguez-Cabello und Francisco Velasco. „The feeding behaviour of some demersal fish species in response to artificial discarding“. Scientia Marina 66, Nr. 3 (30.09.2002): 301–11. http://dx.doi.org/10.3989/scimar.2002.66n3301.

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Johnson, Andrew F., Maria Valls, Joan Moranta, Stuart R. Jenkins, Jan G. Hiddink und Hilmar Hinz. „Effect of prey abundance and size on the distribution of demersal fishes“. Canadian Journal of Fisheries and Aquatic Sciences 69, Nr. 1 (Januar 2012): 191–200. http://dx.doi.org/10.1139/f2011-138.

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Many demersal fish species rely on benthic prey as food sources for part of, or in some cases, all of their life history. We investigated the relationships between prey and predator abundance and prey size and predator mouth gape size for nine demersal fish species. Of the species analysed, four showed a significant positive increase in abundance with increasing prey abundance. Prey size is thought to be an important parameter for demersal fish that are limited in their feeding potential by their mouth gape size, as it influences consumption rate and energy expenditure while foraging. The relationship between prey size and mouth gape was investigated using both stomach content data and prey availability data. Stomach content analysis revealed positive relationships between maximum prey size and predator mouth gape size for six of the species. Indications of prey size selectivity were only seen in the environment for European hake ( Merluccius merluccius ), highlighting the potential importance of prey size over prey abundance for this species. The results demonstrate that prey abundance and size are of significance for some demersal fish species feeding primarily on benthos and will help in defining habitat requirements of demersal fish species.
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Tuapetel, Friesland, Delly DP Matrutty und Welem Waileruny. „Diversity of Demersal Fish Resources in Ambon Island Waters“. Jurnal Iktiologi Indonesia 18, Nr. 3 (09.02.2019): 223. http://dx.doi.org/10.32491/jii.v18i3.315.

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The waters surrounding Ambon Island is a potential fishing gound for demersal fish resources, yet information regarding species diversity is still slightly understood. This research aimed to analyze the diversity of species and size of demersal fish around Ambon Island oceans. Data was collected based on experimental fishing using fish trap at two locations, in northern and southern waters of Ambon Island. The data were collected by experimental capture using fishing gear at two locations, namely northern waters (March-April 2015) and south of Ambon Island (July-October 2016). Methods of demersal resource diversity analysis are several ecological indexes i.e. Shannon-Wiener diversity index, Pielou uniformity index, and Simpson's dominance index. The result showed that 21 family and 57 species with details of 35 species in the northern waters and 32 species in the southern water. Species diversity based on Shannon-Wiener Index (H´) ranged between 1,61-3,10 while species evenness index (E) was around 0,83-0,95. The abundance of demersal fish was not dominated by any fish species, showed by the average Simpson index of dominant (D) around 0,05-0,26.AbstrakPerairan Pulau Ambon termasuk daerah penangkapan sumber daya ikan demersal yang potensial, namun informasi ke-anekaragamannya masih sangat sedikit. Penelitian ini bertujuan untuk menganalisis kekayaan jenis dan keanekara-gaman ikan demersal di perairan Pulau Ambon. Pengambilan data dilakukan dengan cara penangkapan eksperimental dengan menggunakan alat tangkap bubu pada dua lokasi yakni perairan utara (Maret-April 2015) dan perairan selatan Pulau Ambon (Juli-Oktober 2016). Metode analisis keanekaragaman sumber daya ikan demersal menggunakan bebe-rapa indeks ekologi yakni indeks keanekaragaman Shannon-Wiener, indeks keseragaman Pielou, dan indeks dominansi Simpson. Hasil penelitian menunjukkan bahwa di perairan Pulau Ambon teridentifikasi 21 famili dan 57 spesies de-ngan rincian 35 spesies di perairan utara dan 32 spesies di perairan selatan. Status keanekaragaman jenis indeks Shannon-Wiener (H´) berkisar 1,61-3,10 sedangkan indeks keseragaman jenis (E) sebesar 0,83-0,95. Kelimpahan ikan demersal tidak ada yang dominan, ditunjukkan oleh indeks dominan Simpson (D) sebesar 0,05-0,26.
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Auster, Peter J., Jeff Godfrey, Anya Watson, Amy Paquette und Greg McFall. „Behavior of prey links midwater and demersal piscivorous reef fishes“. Neotropical Ichthyology 7, Nr. 1 (März 2009): 109–12. http://dx.doi.org/10.1590/s1679-62252009000100014.

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Pelagic and demersal guilds of piscivorous fishes are linked by a variety of biological and physical processes that mediate interactions with common prey species. Understanding the behaviors of predators and prey can provide insight into the conditions that make such linkages possible. Here we report on the behaviors of mid-water piscivorous fishes and the responses of prey that produce feeding opportunities for demersal piscivorous fishes associated with "live bottom" ledge habitats off the coast of Georgia (northwest Atlantic Ocean). Prey taxa reduced nearest neighbor distances and retreated towards the seafloor during predatory attacks by mid-water fishes. Demersal fishes subsequently attacked and consumed prey in these ephemeral high density patches. No predation by demersal fishes was observed when prey species were at background densities. If the predator-prey interactions of demersal piscivorous fishes are commonly mediated by the predatory behavior of midwater piscivorous fishes and their prey, such indirect facilitative behaviors may be important in terms of the population processes (e.g., prey consumption and growth rates) of these demersal fishes.
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Gray, CA, und NM Otway. „Spatial and temporal differences in assemblages of demersal fishes on the inner continental shelf off Sydney, south-eastern Australia“. Marine and Freshwater Research 45, Nr. 4 (1994): 665. http://dx.doi.org/10.1071/mf9940665.

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Variations in assemblages of demersal fishes occurring in different depths of water (30, 60 and 100 m) on the inner continental shelf off Sydney are described. Assemblages comprised a diverse and abundant ichthyofauna; many species were of economic importance. Classification analyses showed that assemblages of demersal fishes at 30 and 60 m depth were most similar to each other and that they consistently differed from those at 100 m depth. This difference may reflect a change in the demersal ichthyofauna from a nearshore to an offshore assemblage. The depth-delineated differences between assemblages agree with those found in similar studies on demersal fishes in coastal waters elsewhere. The distributions and relative abundances of many species differed markedly among depths, but such differences were not always consistent between localities or throughout time. Despite this, some species showed some temporal affinity with a particular site and/or depth. The study confirmed spatial and temporal variabilities in the demersal fish fauna in coastal waters off Sydney; such heterogeneity must be considered when future studies are designed.
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Angin, Robet Perangin, NFN Sulistiono, Rahmat Kurnia, Achmad Fahrudin und Ali Suman. „Struktur komunitas sumber daya ikan demersal berdasarkan kedalaman perairan di Laut Cina Selatan (WPP-NRI 711) [Community structure of demersal fish resources based on the depth of the waters in the South China Sea (Indonesia Fisheries Management Zone 711)]“. Jurnal Iktiologi Indonesia 17, Nr. 1 (22.08.2017): 67. http://dx.doi.org/10.32491/jii.v17i1.305.

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Information on distribution and community structure of demersal fish resources are important to be known as an input to the management of demersal fisheries. This study aimed to analyze the diversity and distribution of demersal fish resources based on the differences in the depth of the waters and the linkages to the environment. Research conducted in the South China Sea in May to June 2015 by operating a trawl gear in the station preset. The method of analysis of demersal fish diversity use some ecological indices i.e Margalef species richness index, Shannon-Wiener diversity index, Pielou evenness index, and Simpson dominance index. The ecological index value then associated with environmental conditions, using principal component analysis. Distribution of the ecological index indicated the stability of communities demersal fish resources getting better with the increase of depth. The most affected to the level of species richness and distribution of demersal fish were the parameters of depth, temperature and salinity, while the abundance distribution of fishes were associated with dissolved oxygen, and water transparency. The implication, that the water environmental conditions greatly affected the distribution and abundance of demersal fish. AbstrakInformasi mengenai persebaran dan struktur komunitas sumber daya ikan demersal penting sebagai bahan masukan untuk pengelolaan perikanan demersal. Penelitian ini bertujuan untuk menganalisis tingkat keanekaragaman dan persebaran sumber daya ikan demersal berdasarkan perbedaan kedalaman perairan, serta keterkaitannya dengan lingkungan. Penelitian dilaksanakan di Laut Cina Selatan pada bulan Mei sampai Juni 2015 dengan mengoperasikan alat tangkap pukat ikan di stasiun yang telah ditetapkan. Metode analisis keanekaragaman hayati ikan demersal menggunakan beberapa indeks ekologi yaitu indeks kekayaan jenis Margalef, indeks keanekaragaman Shannon-Wiener, indeks keseragaman Pielou, dan indeks dominansi Simpson. Nilai indeks ekologi tersebut kemudian dikaitkan dengan kondisi lingkungan, menggunakan analisis komponen utama. Hasil penelitian menunjukkan tingkat kestabilan komunitas sumber daya ikan demersal semakin baik seiring dengan meningkatnya kedalaman. Kedalaman, suhu, dan salinitas merupakan parameter yang paling memengaruhi tingkat kekayaan jenis serta persebaran sumber daya ikan demersal, sedangkan persebaran kelimpahan ikan sangat terkait dengan oksigen terlarut dan kecerahan perairan. Implikasinya, kondisi lingkungan perairan sangat memengaruhi persebaran dan kelimpahan ikan demersal.
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Dissertationen zum Thema "Demersal specie"

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O'Sullivan, Martha. „Population structure of demersal fish species in the north eastern Atlantic“. Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources. Restricted: no access until Dec. 31, 2010. Online version available for University members only until June 2, 2011, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=26063.

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Kuta, Kevin G. „The Effect of Demersal Reef Fish on Two Species of Gorgonian Coral“. NSUWorks, 1992. http://nsuworks.nova.edu/occ_stuetd/356.

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The effect of demersal reef fish on the gorgonians Pterogorgia anceps and Plexaurella grisea was determined under controlled conditions. Demersal reef fish cause significant changes in Pterogorgia anceps zooxanthellae concentration (cells cm-3), bulk density (g cm-3), and spicule concentration (g cm-3). Growth rates as measured by changes in planar area (cm2) are not significantly affected. No significant differences were found among any of the parameters measured for Plexaurella grisea; however, trends in the data were similar to those of P. anceps.
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Isidro, Eduardo Jose Louca Florencio. „Biology and population dynamics of selected demersal fish species of the Azores Archipelago“. Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307638.

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Moore, Cordelia Holly. „Defining and predicting species-environment relationships : understanding the spatial ecology of demersal fish communities“. University of Western Australia. Faculty of Natural and Agricultural Sciences, 2009. http://theses.library.uwa.edu.au/adt-WU2010.0002.

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[Truncated abstract] The aim of this research was to define key species-environment relationships to better understand the spatial ecology of demersal fish. To help understand these relationships a combination of multivariate analyses, landscape analysis and species distribution models were employed. Of particular interest was to establish the scale at which these species respond to their environment. With recent high resolution surveying and mapping of the benthos in five of Victoria's Marine National Parks (MNPs), full coverage bathymetry, terrain data and accurate predicted benthic habitat maps were available for each of these parks. This information proved invaluable to this research, providing detailed (1:25,000) benthic environmental data, which facilitated the development and implementation of a very targeted and robust sampling strategy for the demersal fish at Cape Howe MNP. The sampling strategy was designed to provide good spatial coverage of the park and to represent the park's dominant substrate types and benthic communities, whilst also satisfying the assumptions of the statistical and spatial analyses applied. The fish assemblage data was collected using baited remote underwater stereo-video systems (stereo- BRUVS), with a total of 237 one-hour drops collected. Analysis of the video footage identified 77 species belonging to 40 families with a total of 14,449 individual fish recorded. ... This research revealed that the statistical modelling techniques employed provided an accurate means for predicting species distributions. These predicted distributions will allow for more effective management of these species by providing a robust and spatially explicit map of their current distribution enabling the identification and prediction of future changes in these species distributions. This research demonstrated the importance of the benthic environment on the spatial distribution of demersal fish. The results revealed that different species responded to different scales of investigation and that all scales must be ix considered to establish the factors fish are responding to and the strength and nature of this response. Having individual, continuous and spatially explicit environmental measures provided a significant advantage over traditional measures that group environmental and biological factors into 'habitat type'. It enabled better identification of individual factors, or correlates, driving the distribution of demersal fish. The environmental and biological measures were found to be of ecological relevance to the species and the scale of investigation and offered a more informative description of the distributions of the species examined. The use of species distribution modelling provided a robust means for the characterisation of the nature and strength of these relationships. In addition, it enabled species distributions to be predicted accurately across unsampled locations. Outcomes of the project include a greater understanding of how the benthic environment influences the distribution of demersal fish and demonstrates a suite of robust and useful marine species distribution tools that may be used by researcher and managers to understand, monitor, manage and predict marine species distributions.
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Sampson, Mark Robert. „Modelling the distribution and abundance of several demersal fish species on the Agulhas Bank, South Africa“. Thesis, Rhodes University, 2002. http://hdl.handle.net/10962/d1006207.

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The Agulhas Bank supports a speciose fish community, many of which are commercially important. Despite substantial research being conducted on aspects of their biology spatial aspects of their distribution and abundance in relation to environment parameters has been ignored. This study, therefore, addressed aspects related to the distribution and abundance of representative species on the Agulhas Bank within a Geographic Information System (GIS). Four candidate species were chosen due to their importance either in numbers or unit mass to the South African demersal trawl fishery. The species also shared morphological and taxonomic similarities. The candidate species chosen were the two Cape hake species, shallow-water hake Meluccius capensis, and deep-water hake Merluccius paradoxus, and the two pleuronectiform species being Agulhas sole Austroglossus pectoralis and redspotted tonguesole Cynoglossus zanzibarensis. The use of a GIS was appropriate and allowed for hidden spatial patterns be exposed and illustrated visually, while also facilitating the quantification of the relationships between distribution/abundance and certain environmental predictors using statistical methods The Department of Marine and Coastal Management, Cape Town, supplied biological data in the form of length frequency and biomass information from spring (AprillMay) and autumn (September/October) cruises conducted between 1986 and 1993 on the R. V. Africana. The Council for National Geoscience, Cape Town, supplied sediment data for the entire southern African coastline. Initial exploratory data analysis highlighted potential relationships between environmental variables and abundance for each specie's life-history stanzas. Variations in spatial distribution were found to be significantly different between each life-history stanzas within species. Fish density as a function of the additive effects of the various environmental parameters, including temperature, depth and sediment type, was assessed using a Poisson Generalized Additive Model (GAM), while distribution was analysed with a logistic GAM. A predictive logistic model was then created, taking into consideration the importance of the predictor variables for each species, allowing for predictive estimates to be made for each species by inputting environmental information within the study area. The importance of certain environmental variables influencing distribution and abundance were noted. General patterns indicated that sediment was the most important to both the distribution and abundance of the two pleuronectiform species and juvenile life-history stanzas, while the adult gadoids' distribution and abundance appeared to be depth dependent.
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Chatfield, Brenton Sean. „How to find the one that got away : predicting the distribution of temperate demersal fish from environmental variables“. University of Western Australia. School of Earth and Geographical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2009.0009.

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Knowing where species are and understanding why is paramount for developing relevant and sustainable conservation and resource management strategies. The need for this information is becoming urgent as fishing activity, resource extraction and the impacts of coastal developments continue to put marine resources under increasing pressure. As logistical and financial constraints can restrict our ability to collect data in the marine environment, the ability to predict distributions based on known associations with different environmental variables would enhance our capacity to manage these resources. Before attempting to predict the distribution of species and groups of species, the underlying species-environment relationships must be examined to determine whether associations between species and the environment can: (i) be identified, (ii) be used to develop models that can accurately predict distributions, and (iii) are general enough to allow accurate predictions beyond the sampled area. Most studies to date have compared the composition of fish assemblages between sites to determine how different environmental variables influence distribution. While widely applied, these methods do not consider how individual species respond to multiple environmental gradients and they lack the ability to predict distributions across different combinations of variables along those gradients. This lack of prediction also limits our capacity to assess what marine biodiversity is presently threatened by global, regional, and local human pressures on marine ecosystems. '...' Thus, summarising and modelling species data at higher levels would result in models with poorer predictive accuracy and a loss of ecological information. The generality of the species-environment relationships defined by the models were assessed by evaluating the transferability of models between different areas. Models developed from data collected over a wider geographic extent could more accurately predict the distribution of species across a smaller spatial extent than vice versa. This indicated that while general theories of the ecology of temperate demersal fish can be defined, the actual patterns of distribution may vary from site to site, suggesting caution when using predictions beyond the sampled area for management purposes. Overall, species distribution modelling identified how different species and groups of species responded to the combined influence of multiple environmental gradients and was able to accurately predict distributions based on the defined associations. Their application has led to a greater understanding of the species environment relationships and will help to identify those areas that may be important for conservation. Their predictive ability will allow general predictions of distribution of fish species across unsurveyed areas and provides the ability to assess the potential impact from implementing different policy and management strategies.
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Guerra, Alessandro. „Estimates of length-at-50% maturity of two South African demersal species: Monkfish, Lophius vomerinus, and Kingklip, Genypterus capensis“. Master's thesis, Faculty of Science, 2019. http://hdl.handle.net/11427/31570.

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Long-lived and slow-growing fish species are especially vulnerable to overfishing. Deep-sea species are elusive and difficult to study, making their management challenging. South African monkfish, Lophius vomerinus, and kingklip, Genypterus capensis, are two demersal species living off the west and south coast of South Africa. These species are exploited as bycatch in the Hake fisheries, and represent an important resource for the fishery. However, reproductive information is scarce, and key life-history parameters have not been updated in recent years. Length-at-50% maturity (L50) is a fundamental biological parameter to monitor stock-health, spawning potential and improve fishery management. This research was focused on computing L50 estimates for both species, separated by sex and coast. As the stock structure for both species is still under debate, reproductive information and L50 estimates were compared between west and south coast. In addition, L50 was compared with previous studies to detect significant differences or changes over time. Demersal survey samples were used. Individuals were classed a 5 stage maturity scale and consequently referred to as mature or immature. For L. vomerinus, a significant difference in L50 between sexes was found, in contrast with previous findings in literature. However, no significant difference between the two areas was reported, corroborating the one-stock hypothesis. Furthermore, I speculate that L. vomerinus aggregate for spawning activities. The analysis of G. capensis revealed differences between coasts, reinforcing the theory of multiple South African stocks. Most importantly, the results showed a critical reduction in females L50 from previous studies. This reduction is believed to be a consequence of excessive fishing pressure exerted particularly during the latter half of the 20th century, which overexploited immature females on the west coast and main female spawners on the south coast. Further research needs to be done to verify these findings and the stock structure of the populations.
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Lelli, Stefano. „Contribution to a better knowledge of biology, distribution and diversity of demersal species along the Lebanese coast, eastern Mediterranean : a focus on Lessepsian fish species“. Thesis, Perpignan, 2017. http://www.theses.fr/2017PERP0051.

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L’objectif de cette étude était de contribuer à une meilleure connaissance des espèces démersales dans les eaux côtières libanaises en Méditerranée orientale. Différents aspects relatifs à la distribution, la diversité, et la biologie de ces espèces ont été étudiés. Les données ont été collectées à partir de captures expérimentales dans le cadre du projet ‘CIHEAM-PESCA Libano’. Un mélange hautement diversifié d'espèces de poissons (téléostéens et sélaciens), de céphalopodes et de crustacés, ainsi que de organismes macro-benthiques ont été échantillonnés. La distribution spatio-temporelle et la diversité ont été évaluées respectivement à l'aide de la ‘capture par unité d'effort’ qui a été assimilée à un indice d’abondance et du nombre total d'espèces capturées dans les relevés.Des relations longueur-poids ont été établies pour plusieurs espèces présentant un nombre d’individus suffisant. Finalement, l'accent a été porté sur la biologie et l'écologie d'une espèce lesseptienne et exploitée, l’holocentre rouge, Sargocentron rubrum. Cette étude constitue une première étape dans la gestion des pêches et la conservation dans cette région
The aim of this study was to contribute to a better knowledge of demersal species in the Lebanese coastal waters, Eastern Mediterranean. Various aspect related to the distribution, diversity and biology of these species were studied. The data were collected from a three-year experimental survey in the framework of the ‘CIHEAM-PESCA Libano project’. A highly diversified mix of fish species (teleosteans and selaceans), cephalopods and crustaceans were sampled. Spatio-temporal distribution and diversity was evaluated respectively using the ‘Catch Per Unit Effort’ which was considered as an approximation of an abundance index and the total number of species caught in the surveys
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Lundy, Caroline. „Genetic structure of demersal fish populations in oceanic environments : implications for management of European hake (Merluccius merluccius), a commercially important species“. Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323388.

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Mafunda, Patrick Siyambulela. „Aspects of the reproduction of male and female African penguins (Spheniscus demersus) with special reference to sperm biology and cryopreservation“. University of the Western Cape, 2018. http://hdl.handle.net/11394/6551.

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Philosophiae Doctor - PhD
In the marine environment, penguins have been described as curators and serve a critical role in ecological balance. The African penguin (Spheniscus demersus) has undergone a rapid population decline, mainly due to disturbances in their natural habitat. The African penguin was up-listed from vulnerable to endangered on the IUCN Red List for Threatened Species in 2010 and thus urgent conservation action is required. Integral to long-term conservation action of any species is a basic knowledge of its reproductive biology, which is currently lacking for African penguins. The main aim of this investigation was to evaluate techniques for the collection of semen in African penguin and to determine sperm quality in order to cryopreserve sperm for in vitro fertilization (IVF) purposes of captive and wild populations. Semen was collected once a week during two breeding seasons from two captive African penguins. Ejaculates (n=51) were obtained over two breeding seasons (Jan-Feb and Jun-Oct) and evaluated for semen volume, sperm concentration, sperm vitality, sperm motility and sperm morphology. In addition twelve (six females and six males, n=4 were breeding pairs) captive African penguins were monitored for hormone (estradiol, testosterone, progesterone) levels prior to and after the egg-laying period.
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Bücher zum Thema "Demersal specie"

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Yáñez-Arancibia, Alejandro. Los peces demersales de la plataforma continental del sur del Golfo de México.: The demersal fishes of the southern Gulf of Mexico shelf. 1, Environmental characterization, ecology and evaluation of species, populations and communities. México, D.F: Universidad Nacional Autónoma de México, Ciudad Universitaria, 1986.

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Lordan, Colm. The distribution and abundance of cephalapod species caught during demersal trawl surveys west of Ireland and in the Celtic Sea. Dublin: The Marine Institute, 2001.

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International Workshop on Acoustic Methods for Demersal Species (1991 St. John's, Nfld.). Proceedings of the International Workshop on Acoustic Methods for Demersal Species; recommendations for acoustic surveys of the Northern Cod stock, St. John's, Newfoundland, August 27-30, 1991. St. John's, Nfld: Science Branch, Dept. of Fisheries and Oceans, 1995.

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Kukche susan kigu tonghyang mit pʻiltŭ gaidŭ: Wŏnyang chŏsŏ ŏjong taesang = A guide to demersal species of the Korean distant water fisheries. Pusan Kwangyŏksi: Haeyang Susanbu Kungnip Susan Kwahagwŏn, 2006.

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Biodiversity of the Weddell Sea: Macrozoobenthic species (demersal fish included) sampled during the expedition ANT XIII/3 (EASIZ I) with RV "Polarstern". Bremerhaven: Alfred-Wegener-Institut für Polar- und Meeresforschung, 2000.

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Mitrea, Marius Cătălin. Ordinul Suveran Militar de Malta. Editura Universitara, 2022. http://dx.doi.org/10.5682/9786062813994.

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Era deja de multa vreme nevoie de o carte in limba romana despre istoria si actualitatea Ordinului Suveran de Malta. Intre numeroasele motive, as aminti, in primul rand, relatiile diplomatice cu Romania, incepute la nivel de Legatie in 1932‑1933, primul reprezentant al Ordinului fiind contele Marie Henry Thierry Michel de Pierredon, iar al Romaniei, printul Dimitrie Ghika, personalitate din galeria marilor nostri diplomati. Relatiile au fost suspendate dupa instalarea regimului comunist, fara sa fie denuntate de o parte sau alta, si reluate la nivel de Ambasada la 24 mai 1991. Dincolo de prestigiul istoric al figurilor care au participat initial la crearea acestor punti, ceea ce legitimeaza din plin demersul din aceasta carte este substanta insasi a activitatii Ordinului pe planul diplomatiei umanitare si, in mod special, prin Serviciul de Ajutor Maltez, fondat in Romania in 1991, o veritabila scoala de voluntariat pentru ajutorarea celor aflati in nevoie. De asemenea, o astfel de carte este binevenita pentru ca poate risipi pentru un cititor onest zvonistica si confuziile care nu au intarziat sa apara nici in tara noastra, aducand Ordinului Suveran de Malta prejudicii nemeritate de imagine sau indepartand complet atentia de la activitatea sa sociala spre chestiuni fantasmagorice referitoare la cavaleri si secrete.
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Sora, Alina Elena. Vasili Grossman. Adevaruri rostite printre lacrimi. Editura Universitara, 2021. http://dx.doi.org/10.5682/9786062813772.

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Proiectata ca o abordare in profunzime a operei sale, lucrarea de fata este fundamentata pe creatia unui scriitor care in prima etapa a carierei artistice se raliaza la ideile socialiste, ulterior, mizand pe libertate si adevar ca urmare a persecutiei si izolarii la care este supus de catre exponentii regimului totalitar sovietic – consecinte inevitabile suportate de scriitorii care dovedeau suficient curaj pentru a nu urma directivele ideologice. Caracterizata de un tragism evident, opera lui Vasili Semionovici Grossman se inscrie in sfera literaturii dezumanizarii. Tradusa in multe limbi si vanduta intr‑un numar mare de exemplare, in special in Occident, creatia grossmaniana a captivat atentia publicului larg si a criticilor, insa acest fenomen s‑a petrecut relativ recent, fapt datorat includerii scriitorului de catre ideologii sovietici in randul autorilor incomozi. De altfel, in spatiul cultural romanesc, abia dupa 1990 se observa o usoara crestere a interesului publicului pentru creatia lui Vasili Grossman, dat fiind faptul ca incepand cu acest an cititorul roman are acces la operele sale majore, si anume Panta rhei si Viata si destin. Daca se are in vedere aspectul receptarii critice a operei lui Grossman in Romania, se impune recunoasterea laturii deficitare a acestui fenomen care se remarca doar prin actiuni sporadice. In consecinta, una dintre premisele acestui volum il constituie analiza in termeni de amanunt a prozei scriitorului rus, cu precadere a celor doua opere fundamentale – Viata si destin si Panta rhei – din perspectiva contextului literar, istoric si social in care se incadreaza, a tematicii abordate, dar si a receptarii ei, in Romania, in Occident, dar si in spatiul rus. Acest demers a devenit posibil apelandu‑se la studii de critica literara in limbile romana, rusa, engleza si, de asemenea, prin compararea cu alte opere, s‑a utilizat in acest sens ca principal instrument de analiza literara intertextualitatea. Aceasta metoda a permis conturarea unei imagini cat mai clare a fenomenului literar analizat, a situarii operei lui Grossman in respectivul context literar, dar si a intelegerii acestuia in conjunctura istorico‑sociala, culturala si psihologica a sangerosului secol XX.
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Buchteile zum Thema "Demersal specie"

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Fernández-Peralta, Lourdes, Eva García-Isarch, Ramón García-Cancela, Isabel Muñoz, Francisca Salmerón, Miguel Ángel Puerto und Susana S. de Matos-Pita. „Faunistic Collections of Demersal and Benthic Species from Mauritania“. In Deep-Sea Ecosystems Off Mauritania, 593–613. Dordrecht: Springer Netherlands, 2017. http://dx.doi.org/10.1007/978-94-024-1023-5_16.

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Takami, Munehiro. „Ecological Diversity of Larval Fishes: Ontogeny of Deep-Sea Demersal Species“. In Fish Diversity of Japan, 263–82. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7427-3_15.

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Turner, George F., Denis Tweddle und Ramsey D. Makwinja. „Changes in demersal cichlid communities as a result of trawling in southern Lake Malaŵi“. In The Impact of Species Changes in African Lakes, 397–412. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0563-7_18.

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Wagner, Hans-Joachim. „Sensory Brain Areas in Deep Sea Slickheads, Eels, and Grenadiers: Comparison of Mesopelagic and Demersal Species“. In The Senses of Fish, 128–46. Dordrecht: Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-94-007-1060-3_6.

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Mackinson, Steven, Michael Park und Barrie Deas. „Does Slow-Burn Collaboration Deliver Results? Towards Collaborative Development of Multi-Annual Multi-Species Management Plans in North Sea Mixed Demersal Fisheries“. In Collaborative Research in Fisheries, 179–91. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-26784-1_11.

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Mullasseri, Sileesh, und Madhusoodana B. Kurup. „Taxonomic and Phylogenetic Indices of Species Assemblages in the Deep-Sea Demersal Ichthyofauna of the South-eastern Arabian Sea: Simple Measures of Diversity for Marine Ecosystem-Based Management“. In Impact of Climate Change on Hydrological Cycle, Ecosystem, Fisheries and Food Security, 341–51. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003299769-33.

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Brander, K. „Demersal Species Fisheries“. In Encyclopedia of Ocean Sciences, 718–25. Elsevier, 2001. http://dx.doi.org/10.1006/rwos.2001.0449.

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Brander, K. „Demersal Species Fisheries“. In Encyclopedia of Ocean Sciences, 90–97. Elsevier, 2001. http://dx.doi.org/10.1016/b978-012374473-9.00449-5.

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Khedkar, G. D., B. V. Jadhao, C. D. Khedkar und N. V. Chavan. „FISH | Demersal Species of Temperate Climates“. In Encyclopedia of Food Sciences and Nutrition, 2424–28. Elsevier, 2003. http://dx.doi.org/10.1016/b0-12-227055-x/00468-5.

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Khedkar, G. D., B. V. Jadhao, N. V. Chavan und C. D. Khedkar. „FISH | Demersal Species of Tropical Climates“. In Encyclopedia of Food Sciences and Nutrition, 2438–42. Elsevier, 2003. http://dx.doi.org/10.1016/b0-12-227055-x/00472-7.

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Konferenzberichte zum Thema "Demersal specie"

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Mueter, F. J., und B. L. Norcross. „A Multivariate Approach to Monitoring Changes in Species Composition of a Demersal Fish Community“. In Ecosystem Approaches for Fisheries Management. Alaska Sea Grant, University of Alaska Fairbanks, 1999. http://dx.doi.org/10.4027/eafm.1999.42.

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Madirolas, Adrian, Gustavo Alvarez Colombo und Federico Castro Machado. „Vertical distribution of a demersal fish species and its implication on the acoustic detection and assessment of argentine hake (Merluccius hubbsi)“. In 2015 IEEE/OES Acoustics in Underwater Geosciences Symposium (RIO Acoustics). IEEE, 2015. http://dx.doi.org/10.1109/rioacoustics.2015.7473630.

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Suzuki, Katsuya, und Tsutomu Takagi. „Dynamics of Boat Seine Fishing Using a Net Geometry Simulator“. In ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-58021.

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Boat seine fishing is used to catch mainly demersal species; it has many benefits such as reduced energy and labor costs, and low damage to the sea bottom if it is controlled. This fishing technique has complex motion between the seine boat and the supple net over large operating areas; therefore, the dynamics of its operating processes during fishing are unknown. To investigate the dynamics of boat seine fishing in detail, we calculated its dynamics during a fishing operation using a net geometry simulation system that we developed. Two experimental surveys were carried out in January 2007 at Hokkaido, Japan. Latitude, longitude, and depth were measured in 10 places, from casting the anchor buoy to picking up the seine net. Depth sensors were installed at the top and bottom of the seine net mouth to record a time series of net shape during fishing. Using our net geometry simulator, we simulated net shape and the dynamics of boat seine fishing based on ship position and net depth. Very close agreement was observed between the experimental and simulated depths of the top and bottom of the net mouth during fishing. Three-dimensional visualization of the simulation results showed the capture processes of this fishing technique in a large scale operation. This study shows that our method is valid for modeling fishing operations to better implement smart fishing.
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Berichte der Organisationen zum Thema "Demersal specie"

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Mudge, Christopher, Bradley Sartain, Benjamin Sperry und Kurt Getsinger. Efficacy of florpyrauxifen-benzyl for eurasian watermilfoil control and nontarget Illinois pondweed, elodea, and coontail response. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/42063.

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This research evaluated low concentrations and short exposure times of the recently registered aquatic herbicide florpyrauxifen-benzyl (4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)-5-fluoro-pyridine-2-benzyl ester) on the target plant Eurasian watermilfoil (Myriophyllum spicatum L., hereafter referred to as EWM) as well as selectivity towards the nontarget submersed species Illinois pondweed (Potamogeton illinoensis Morong), elodea (Elodea canadensis Michx.), and coontail (Ceratophyllum demersum L.)
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Coram, Alexander James, Allen Robert Kingston und Simon Northridge. Cod catches from demersal and pelagic trawl gears in the Clyde estuary: results from an industry-led survey in 2016: a report on behalf of the Clyde Fishermen's Association. Marine Alliance for Science and Technology for Scotland (MASTS), August 2022. http://dx.doi.org/10.15664/10023.26247.

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[Extract from Foreword] This ‘cruise report’ is the first of a short series, reflecting the aspiration of the Clyde Fishermen’s Association to establish a rigorous sampling scheme to monitor changes in the abundance and distribution of cod (and later other gadoid species) within the Clyde area. The Scottish Oceans Institute was approached to provide independent scientific support in early 2016. A series of surveys was then conducted in 2016, 2017 and 2018. In each survey the SOI provided observers, collected data and wrote up a cruise report detailing the methods used and the location, numbers, weights, sex and maturity states of fish caught. Trials were halted after 2018 firstly because of pressing issues resulting from Brexit which absorbed any potentially available human and other resources, and secondly because of the COVID pandemic. The reports remained as unapproved and incomplete drafts until 2022. Picking up these reports again in 2022, we have responded to reviewers’ comments since made by Marine Scotland Science and have finalised all four reports in the 2016-2018 current series.
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Mudge, Christopher, und Kurt Getsinger. Comparison of generic and proprietary aquatic herbicides for control of invasive vegetation; part 3 : submersed plants. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/42061.

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Herbicide selection is key to efficiently managing nuisance vegetation in our nation’s waterways. After selecting the active ingredient, there still remains multiple proprietary and generic products to choose from. Recent small-scale research has been conducted to compare the efficacy of these herbicides against floating and emergent species. Therefore, a series of mesocosm and growth chamber trials were conducted to evaluate subsurface applications of the following herbicides against submersed plants: diquat versus coontail (Ceratophyllum demersum L.), hydrilla (Hydrilla verticillata L.f. Royle), southern naiad (Najas guadalupensis (Sprengel) Magnus), and Eurasian watermilfoil (Myriophyllum spicatum L.); flumioxazin versus coontail, hydrilla, and Eurasian watermilfoil; and triclopyr against Eurasian watermilfoil. All active ingredients were applied at concentrations commonly used to manage these species in public waters. Visually, all herbicides within a particular active ingredient performed similarly with regard to the onset and severity of injury symptoms throughout the trials. All trials, except diquat versus Eurasian watermilfoil, resulted in no differences in efficacy among the 14 proprietary and generic herbicides tested, and all herbicides provided 43%–100% control, regardless of active ingredient and trial. Under mesocosm and growth chamber conditions, the majority of the generic and proprietary herbicides evaluated against submersed plants provided similar control.
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Tsybekmitova, G. Ts, L. D. Radnaeva, N. A. Tashlykova, V. G. Shiretorova, A. K. Tulokhonov, B. B. Bazarova und M. O. Matveeva. THE EFFECT OF CLIMATIC SHIFTS ON BIODIVERSITY OF PHYTOCENOSIS: LAKE ARAKHLEY (EASTERN SIBERIA, RUSSIA). DOICODE, 2020. http://dx.doi.org/10.18411/0973-7308-2020-35-3-77-90.

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Lake Arakhley is located within the Lake Baikal basin in Eastern Siberia, Russia. The area is characterized by continental subarctic climate with considerate diurnal temperature range, long cold dry winters and short hot summers with more precipitation occurring during the latter half of the summer. Climatic shifts in high water years and low water years result in morphometric changes in the lake and in the chemical and physical parameters of the ecosystem. During low water years, concentrations of ammonium nitrogen and nitrite nitrogen are decreased, whereas nitrate concentration increases. High water years feature average concentrations of ammonium ions 1.5–2 times higher than the values of recent dry years. Redundancy analysis (RDA) of abiotic factors and biotic community indicated that the community structure shows the greatest correlation with physical and chemical parameters of water and biogenic elements (nitrites, ammonium, phosphates) along the first axis, and with the lake depth and transparency along the second axis. Changes in abiotic factors induce functioning and formation of characteristic communities of the primary producers in the trophic structure of the ecosystem. During low water years, with increased level of autochthonous organic matter, Lindavia comta dominance is observed, while during high water years, with increased allochthonous organic matter Asterionella formosa appeared as dominant. Currently, during low water years, the hydrophytes community is monodominant and composed of Ceratophyllum demersum. Meanwhile, such species indicating eutrophic conditions as Myriophyllum sibiricum, Potamogeton pectinatus are found in the lake vegetation.
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