1,721,212 research outputs found
Maximising sustainable nutrient production from coupled fisheries-aquaculture systems
Full text linkAquaculture expansion is expected to meet growing demand for sustainable animal-source foods. Yet marine-fed species already require millions of tonnes of wild-caught fish for feed, over 90% of which are nutritious food-grade species. Allocating feed fish for human consumption could reduce pressure on marine resources while increasing seafood production. We examine micronutrient flows (the transfer of micronutrients from feed to fish) in Scotland's farmed salmon industry, which is particularly reliant on marine feeds, to show that 1-49% of essential dietary minerals and fatty acids available in wild fish are retained in farmed salmon. Using three alternative production scenarios we show that reducing marine feeds in salmon production and allocating wild-caught feed fish for human consumption could produce more nutritious seafood and leave 66-82% of feed fish in the sea. Using global data on marine-fed aquaculture production, we show that removing wild-caught fish from salmonid production could leave 3.7 Mt fish in the sea while increasing global seafood production by 6.1 Mt
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Ligula intestinalis infection of Pseudorasbora parva in Hirfanlı Dam Lake, Kırşehir, Turkey
Full text linkLigula intestinalis was found during the parasitological investigations of Pseudorasbora parva specimens collected from Hirfanlı Dam Lake, Turkey. It was found that 8.78% of all specimens were infected with L. intestinalis including 17 female (3.8%) and 22 males (4.95%). It was determined that the length–weight relationship equivalents of infected individuals with population differed from those of non-infected individuals. The b value of the infected individuals was found to be lower than the b value of the non-infected individuals. It is thought that the results obtained in this study will be beneficial in preserving and improving the ecological potential of the lake
Concentrations of Arsenic and Boron in Water, Sediment and the Tissues of Fish in Emet Stream (Turkey)
No full textIn this study, the concentrations of arsenic and boron were determined in the water and the sediment, as well as in the muscle tissues of Squalius cephalus, Alburnoides bipunctatus, Barbus plebejus and Capoeta tinca from Emet Stream. The fish samples were caught in May 2011 and September 2012. The metal concentrations in the water samples were as follows: arsenic was 137.1-1002 A mu g L-1, and boron was 2421-14490 A mu g L-1. The metal concentrations in the sediment samples were as follows: arsenic was 14.51-3317.1 mg kg(-1), and boron was 14.22-1014.01 mg kg(-1). The mean tissue concentration of arsenic was lower than the TFC and WHO limits. Boron has been identified in fish tissues at concentrations between 0.26 and 2.96 mg kg(-1). The bioaccumulation in the muscle tissues of all fish species caught from Emet Stream did not exceed the limit values
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Population structures and some growth properties of tench (Tinca tinca L., 1758) in Mogan Lake, Ankara, Turkey
No full textTrdizinScopu
Growth Properties of Endemic Aphanius marassantensis in Hirfanli Reservoir, Turkey
No full textGrowth properties and length weight relationship are determined for endemic Aphanius marassantensis Pfleiderer, Geiger & Herder, 2014 in Hirfanli Reservoir. A total of 305 individuals are (115 females, 190 males) determined with a random method by using a gill nets (1.2 x 2 cm mesh sizes). Length weight relationship was W = 0.01075342 L-3.415 (R-2 = 0.881) for females, W = 0.01138892L(3.364) (R-2 = 0.904) for males. The Von Bertalanffy equations were L-t = 6.18 [1 - e(-0.191(t + 1.770))], W-t = 4.01 [1 - e(-0.191(t + 1.770))] for females, L-t = 7.07 [1 - e(-0.133 (t + 2.380))], W-t = 5.89[1 - e(-0.133 (t + 2.380))] for males. Aphanius is an endemic fish species and it shows its importance in terms of biodiversity. It is necessary to increase knowledge about endemic species and to monitor population trends and status
Bioacumulation of Arsenic and Boron in Water Sediments and Tisues of Fishes from Emet Stream Turkey
No full textFirst record of the big-scale sand smelt (Atherina boyeri Risso, 1810, Pisces: Atherinidae) from Porsuk Dam Lake, Türkiye
Full text linkThis study represents a preliminary report on the occurrence of Atherina boyeri in the Porsuk Dam Lake, with a total of 420 individuals obtained from local fishermen between May and July 2023. Of these specimens, 34.76% (146 individuals) were males and 65.24% (274 individuals) were females, resulting in a calculated sex ratio (females:males) of 1:0.53. The total length of the sampled fish ranged from 6.06 to 10.84 cm and their weight ranged from 1.34 to 8.60 g. The length–weight relationship (LWR) based on total length was calculated as W = 0.00001003 L2.9359 for the female population, W = 0.00000525 L3.0665 for the male population, and W = 0.00000474 L3.0975 for the entire population. The exponential value of the total length to weight ratio, denoted as ‘b’, was determined as 3.0975, indicating isometric growth for the species. The mean value of the condition factor for females, males, and all individuals of A. boyeri was determined as 0.755 ± 0.085, 0.710 ± 0.076, and 0.740 ± 0.084, respectively. This study not only provides preliminary and valuable data on the presence of A. boyeri in the Porsuk Dam Lake, but also offers a significant perspective on the biodiversity of the new habitat. The findings of the study are considered to be applicable to local fisheries management authorities and decision-makers to ensure the sustainability of fishery resources and the implementation of appropriate fisheries management strategies.This study represents a preliminary report on the occurrence of Atherina boyeri in the Porsuk Dam Lake, with a total of 420 individuals obtained from local fishermen between May and July 2023. Of these specimens, 34.76% (146 individuals) were males and 65.24% (274 individuals) were females, resulting in a calculated sex ratio (females:males) of 1:0.53. The total length of the sampled fish ranged from 6.06 to 10.84 cm and their weight ranged from 1.34 to 8.60 g. The length–weight relationship (LWR) based on total length was calculated as W = 0.00001003 L2.9359 for the female population, W = 0.00000525 L3.0665 for the male population, and W = 0.00000474 L3.0975 for the entire population. The exponential value of the total length to weight ratio, denoted as ‘b’, was determined as 3.0975, indicating isometric growth for the species. The mean value of the condition factor for females, males, and all individuals of A. boyeri was determined as 0.755 ± 0.085, 0.710 ± 0.076, and 0.740 ± 0.084, respectively. This study not only provides preliminary and valuable data on the presence of A. boyeri in the Porsuk Dam Lake, but also offers a significant perspective on the biodiversity of the new habitat. The findings of the study are considered to be applicable to local fisheries management authorities and decision-makers to ensure the sustainability of fishery resources and the implementation of appropriate fisheries management strategies
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