Search results for "Fish"
showing 10 items of 3164 documents
Simultaneous optimization of harvest schedule and measurement strategy
2013
In many recent studies, the value of forest inventory information in the harvest scheduling has been examined. Usually only the profitability of measuring simultaneously all the stands in the area is examined. Yet, it may be more profitable to concentrate the measurement efforts to some subset of them. In this paper, the authors demonstrate that stochastic optimization can be used for defining the optimal measurement strategy simultaneously with the harvest decisions. The results show that without end-inventory constraints, it was most profitable to measure the stands that were just below the medium age. Measuring the oldest stands was not profitable at all. It turned out to be profitable t…
Gill area explains deviations from body size–metabolic rate relationship in teleost fishes
2022
Whether gill area constrains fish metabolism through oxygen limitation is a debated topic. Here, the authors provide insights into this question by analysing mass-specific metabolic rates across 44 teleost fishes extracted from FishBase. They explore whether species deviations from metabolic rates predicted by body mass can be explained by species gill area. They show that the gill area explains c. 26%–28% of species-level deviations from mass-specific metabolic rates. Their findings suggest that gill area might indeed be one of the factors limiting metabolic rate in fishes.
Haemolymphatic Parameters in Two Aquaculture Crustacean Species Cherax destructor (Clark, 1836) and Cherax quadricarinatus (Von Martens, 1868)
2022
In the last few years, there has been a notable development in the breeding of freshwater shrimp (astaciculture), which involved various species and in particular, the two Australian Parastacidae species, Cherax destructor and Cherax quadricarinatus. Information about the haemolymphatic parameters of these two species is fragmentary, and filling these gaps becomes important given their importance in aquaculture. Cellular and biochemical parameters were analyzed in both species to create a reference baseline for these parameters to identify the state of welfare or suffering of these animals. The results showed that the total haemocyte count, haemocyte subpopulations, enzymatic activities and…
Honey Bee Pollen in Meagre (Argyrosomus regius) Juvenile Diets: Effects on Growth, Diet Digestibility, Intestinal Traits, and Biochemical Markers Rel…
2020
This research aimed to evaluate the effects of the inclusion of honey bee pollen (HBP) in meagre (Argyrosoumus regius) juveniles&rsquo
Design, fabrication and evaluation of an online Intelligent machine for trout beheading and gutting
2021
La clasificación y procesado de pescado empleando máquinas automáticas reduce costes e incrementa el volumen de procesado. Después de su llegada a los mercados de distribución mayorista y minorista, el tamaño de los ejemplares suele ser muy variado para la mayoría de las especies (trucha, caballa, dorada, lubina, etc.). Debido a ello, la limpieza y corte de pescado se realiza habitualmente de forma manual. Este proceso involucra diferentes pasos y a menudo se corta en función de la demanda del usuario: sin cabeza, sin vísceras, sin cabeza ni vísceras, fileteado, etc. Combinando diferentes elementos tecnológicos, hoy en día es posible el desarrollo de sistemas automáticos capaces de mejorar …
Farming intensity indirectly reduces crop yield through negative effects on agrobiodiversity and key ecological functions
2022
International audience; Farming intensity and landscape heterogeneity influence agrobiodiversity and associated ecological functions. The relative contributions of these agroecosystem components to agricultural production remain unclear because of inter-relations and weather-dependant variations. Using a structural equation modelling approach, we estimated direct and indirect contributions of farming intensity (soil management, pesticide use and fertilisation) and landscape heterogeneity (of semi-natural covers and crop mosaic) to cereal crop production, in 54 fields (mostly wheat), in two years (24 and 30 fields). Indirect effects were evaluated through agrobiodiversity (carabid and plant …
Effects of UV Radiation and Diet on Polyunsaturated Fatty Acids in the Skin, Ocular Tissue and Dorsal Muscle of Atlantic Salmon (Salmo salar) Held in…
2010
Article published in Photochemistry and Photobiology, 86 (4): 909-919 JUL-AUG 2010 The effect of UV radiation (UVR) on juvenile Atlantic salmon (Salmo salar) was assessed by measuring the fatty acid (FA) profiles of muscle, dorsal and ventral skin, and ocular tissues following 4-month long exposures to four different UVR treatments in outdoor rearing tanks. Fish were fed two different diets (Anchovy- and Herring-oil based) that differed in polyunsaturated fatty acid (PUFA) concentrations. Anchovy-fed salmon had higher concentrations of ALA (alpha-linoleic acid; 18:3n-3), EPA (eicosapentaenoic acid; 20:5n-3) and DPA (docosapentaenoic acid, 22:5n-3) in their muscle tissues than fish fed the H…
Pathways for the amplification of agroecology in African sustainable urban agriculture
2020
A growing awareness that highly intensified agricultural systems have made a substantial worldwide contribution to the worsening of the resilience capacity of natural ecosystems has, over the last twenty years, brought general attention to agroecological management models. This aspect is even more evident in industrial agriculture, which is based on the use of multiple chemical products derived from non-natural synthesis. In more developed countries, a new idea of ecology linked to agricultural production has been increasingly developed and, for this reason, there has been a greater diffusion of differentiated agricultural models taking into consideration the environmental impact of product…
From Analysis to Formulation of Strategies for Farm Advisory Services (Case Study: Valencia – Spain). an Application through Swot and Qspm Matrix
2019
Abstract European agriculture should meet new increasing internal and contextual challenges. For example, the reform of the Common Agricultural Policy in 2003 introduced the cross-compliance, among other novelties, as compulsory for farmers. To better meet this and other requirements, Member States had to set up the so-called Farm Advisory System, operational across the European Union in 2007. From a sample of actors involved in the provision of farm advisory services in the region of Valencia (Spain), the present study aimed to identify the most appropriate strategies to implement such services. SWOT method has been applied to examine the internal and external environment. Based on this di…
Behavioural adaptations of argulid parasites (Crustacea: Branchiura) to major challenges in their life cycle
2015
Fish lice (Argulus spp.) are obligate ectoparasites, which contrary to most aquatic parasites, retain the ability to swim freely throughout the whole of their life. In fish farms, they can quickly increase in numbers and without effective control cause argulosis, which results in the reduced growth and survival of their fish hosts. The morphology of Argulus spp, including their sensory organs, is suitable for both parasitism and free-swimming. By spending a considerable amount of time away from their host, these parasites risk being excessively dispersed, which could endanger mating success. Here we present a review of recent studies on the behaviour of Argulus spp, especially the aggregati…