Quality of Mince from Alaska Pollock (Theragra chalcogramma) Frames     

《Journal Of Aquatic Food Product Technology》2013,22(1):7-17

The quality and frozen stability of minces produced from Alaska pollock (Theragra chalcogramma) frames were compared against commercially produced fillet mince. Fresh frame mince had a higher defect level, lower nutritional content, and darker color. Cooked frame mince had a softer texture than commercial mince. After 6 mo frozen storage, frame mince had deteriorated to where it had unacceptable color, flavor and cooked texture. Rancidity increased more rapidly in frame mince than commercial fillet mince. Blending frame mince at levels of 10% to 20% with commercial mince produced acceptable fresh quality but marginal frozen storage stability.  相似文献   

Host and environmental risk factors associated with Cryptosporidium scophthalmi (Apicomplexa) infection in cultured turbot, Psetta maxima (L.) (Pisces, Teleostei)     

Pilar Alvarez-Pellitero  Andrs Perez  M. Isabel Quiroga  M. Jos Redondo  Sonia Vzquez  Ana Riaza  Oswaldo Palenzuela  Ariadna Sitj-Bobadilla  Jos M. Nieto 《Veterinary parasitology》2009,165(3-4):207-215

An epidemiological cohort study of Cryptosporidium scophthalmi in cultured turbot Psetta maxima L. of Northwestern Spain was conducted along a four-year period. Four different ongrowing cohorts were monitored monthly from introduction into the ongrowing tanks (10–50 g) until reaching market size (400–1400 g). The association of host and environmental factors with five categories of parasite abundance was assessed using a multivariable regression framework. Epidemiological factors assessed here were water temperature, weight, length, month of collection, season, age, origin, condition factor, water filtration, and status to the myxozoan Enteromyxum scophthalmi infection. E. scophthalmi was included into the analysis because it targets the same organ than C. scophthalmi and it was prevalent in the studied population. The multivariable analysis demonstrated the statistically significant association between several factors and parasite abundance. C. scophthalmi abundance was associated (P < 0.05) with age, condition factor, season, and status to E. scophthalmi infection. Young animals, with poor condition factor, during spring or summer, and not infected with the myxozoan were most likely to be highly infected by C. scophthalmi. Inclusion of these four variables significantly (P < 0.05) improved the model, compared to the model that did not include any of these epidemiological factors. Increasing levels of C. scophthalmi abundance were associated (P < 0.01) with higher severity of C. scophthalmi-compatible lesions. The frequency of distribution of C. scophthalmi abundance was clearly right-skewed and fitted a negative binomial distribution, whereas the intensity of infection fitted a Poisson distribution. The quantification of the variance-to-mean ratio stratified by age demonstrated overdispersion for 8–16 months old fish, although this bivariate association is likely affected by several other factors, as suggested by the results of the multivariable analysis. The negative relation between C. scophthalmi abundance and status to E. scophthalmi infection suggests differences in the transmission, onset, and course of both infections. The coarse filtration used in some cohorts did not significantly affect the levels of infection. C. scophthalmi was probably introduced into the ongrowing tanks mainly with carrier fish, though the involvement of infective oocysts from the water supply cannot be disregarded. Infection prevalence and mean intensity decreased with fish age and a seasonal distribution was found. Results presented here will help to understand the epidemiology of C. scophthalmi in turbot, to estimate the expected levels of infection associated with presence or absence of epidemiological factors, and to quantify the impact that the disease may have on susceptible turbot populations. The multivariable model used here is more powerful than the visual inspection of graphics for exploring associations in cooperative processes and can be easily extended to the assessment of epidemiological associations in other population and parasitic diseases.  相似文献   

用熵权模糊综合评价法评价养殖池塘水质状况的研究     

吴会民  张韦  梁传辉  樊振中  谢刚  高勇  缴建华 《安徽农业科学》2012,40(10):6110-6112,6115

[目的]利用熵权模糊综合评价法对养殖池塘水质状况进行评价,以期能对池塘养殖的水质评判提供参考。[方法]利用熵权模糊综合评价法评价以乌克兰鳞鲤(Cyprinus carpio)为主养鱼,平均规格71.4 g/尾,密度分别为6 000、9 000、12 000尾/hm2的3组池塘的水质情况。[结果]根据我国地表水环境质量标准GB3838-2002,在养殖过程中,6 000尾/hm2组池塘属Ⅰ类水,9 000和12 000尾/hm2组池塘属Ⅴ类水。[结论]随着养殖密度的增大,池塘水质逐渐变差,但从综合评价结果也可看出9 000和12 000尾/hm2组池塘的水质没有差异。  相似文献   

基于直接碳汇核算的长三角地区海水贝类养殖发展分析     

岳冬冬  王鲁民 《山东农业科学》2012,44(8):133-136

海水贝类养殖是形成渔业碳汇的重要途径之一。以海水贝类养殖直接碳汇核算原理为基础,通过对2010年全国海水贝类养殖直接碳汇进行核算,得出以下结论:(1)2010年我国海水贝类养殖直接碳汇总量约97×104t,其中,按省区排序,山东省位居第一,而按品种排序,牡蛎则是主要来源;(2)长三角地区海水贝类养殖直接碳汇量不具有优势,仅占总量的11.58%。为了提高长三角地区碳汇渔业发展地位,以相应海区养殖容量为基础,提出两点建议:一是借助地区内外两种资源,提高长三角地区海水贝类养殖产量;二是在现有养殖产量基础上,通过优化海水贝类养殖结构,提高贻贝养殖比重以实现增汇,据估算,养殖结构调整可使江苏、浙江两省碳汇量分别提高到18 703.87 t和9 048.56 t。  相似文献   

青岛市水产业经济增长方式转变研究     

辛德树  刘学忠 《安徽农业科学》2012,(5):3088-3090

对青岛市水产业经济增长方式进行了分析,研究了制约其增长的因素,在此基础上提出了相应的建议,即通过水产品质量安全技术创新、水域生态安全技术创新、水产品良种繁育技术创新、完善水产业科技创新体系,大力发展休闲渔业等第三产业,实现青岛市水产业经济增长方式的转变。  相似文献   

Horizontally integrated aquaculture development: Exploring consensus on constraints and opportunities with a stakeholder Delphi     

Stuart W. Bunting 《Aquaculture International》2008,16(2):153-169

Horizontal integration represents a technically viable opportunity for aquaculture producers to reduce environmental impacts whilst apparently enhancing production efficiency and gaining from economies of integration. Despite significant research, pilot-scale developments and recommendations advocating adoption by producers, uptake has been limited. Consequently, research was undertaken, invoking the iterative Delphi methodology, to explore consensus amongst a multidisciplinary stakeholder panel concerning the nature and significance of constraints and opportunities associated with horizontal integration. Round 1 participants (n = 24) submitted 84 and 94 statements identifying constraints and opportunities, respectively, within physical, environmental, managerial, institutional, economic and social subcategories; aggregating similar statements produced 29 distinct constraints and 27 opportunities for subsequent evaluation. Friedman’s randomised block analysis indicated similar rank patterns (P < 0.001, two-tailed) in the distribution of weights assigned to opportunities and constraints by panel members after round 3. Kendall’s coefficient of concordance (W) indicated that agreement on constraints was ‘strong’ and confidence in rank patterns ‘high’; agreement was ‘very strong’ and confidence ‘high’ to ‘unusually high’ concerning opportunities. Agreement within subcategories ranged from ‘unusually high’ for physical and environmental constraints and opportunities to ‘moderate’ for institutional and social constraints. Economic, physical and managerial constraints were ranked highest, as compared with environmental and physical opportunities. These findings confirm that constraints and opportunities associated with horizontal integration are multifaceted and that a multidisciplinary, systems-based approach to aquaculture development is critical. Furthermore, the stakeholder Delphi constitutes a promising approach to facilitating constructive dialogue and consensus-building amongst diverse, antagonistic and hierarchical stakeholder groups frequently associated with aquaculture development.  相似文献   

Efficiency of producing bioflocs with aquaculture waste by using poly-β-hydroxybutyric acid as a carbon source in suspended growth bioreactors     

《Aquacultural Engineering》2017

With additional organic carbon, fish waste can be used as a substrate to produce bioflocs, a protein source for aquaculture animals. In choosing a carbon source, one should consider convenience, cost and biodegradability. This study investigates the efficiency of poly-β-hydroxybutyric acid (PHB), a biologically degradable polymer, as a carbon source to produce bioflocs in suspended growth bioreactors (SGRs), PHB-SGRs, compared with glucose (GLU-SGRs). The C:N ratio in PHB-SGRs could be maintained around 15:1. The volatile suspended solids (VSS) yield was 2.94 ± 0.72 gVSS/g fish waste for PHB-SGRS and 4.90 ± 0.23 gVSS/g fish waste for GLU-SGRs. The recycling rate of nitrogen in aquaculture solid waste was 56 ± 2% and 87 ± 7% for the PHB-SGRs and Glu-SGRs. No significant differences were found in the bioflocs produced and in the crude protein content of the produced bioflocs between PHB-SGRs and GLU-SGRs. PHB-SGRs and GLU-SGRs could remove dissolved inorganic nitrogen from aquaculture wastewater, with average values of 11.82 ± 8.95 and 16.27 ± 3.95 mg/g TSS/d. Because the calculation of the added amount of carbon and the multiple additions of carbon was avoided, PHB is considered to be a good choice as an organic carbon source for this process, even though not all parameters used for assessment were better than those of GLU-SGRs.  相似文献   

Testing the efficacy of bouncing-bucket nursery systems for enhancing shell strength and thickness in on-bottom cultured Eastern oysters (Crassostrea virginica)     

《Aquacultural Engineering》2020

Through physical manipulation, oyster growers can modify the morphological features of young oysters in order to improve their robustness and resiliency to predation. In this study, the efficacy of a novel passive culturing technique using floating buckets that “bounce” oysters prior to the benthic grow-out phase for enhancing shell thickness and strength, while not compromising oyster shape, was investigated. Using a field experiment, we quantified and compared the shell thickness (mm), compressive strength (Newtons), and shape (fan ratios and cup ratios) of juvenile oysters subjected to this bouncing technique with oysters grown in floating bags, the current industry standard. Results indicated that bouncing increased shell thickness and strength for oysters >45 mm shell height compared to control oysters, but also decreased shell thickness and strength for oysters <45 mm shell height compared to control oysters. There was no difference in shell shape between bounced and control oysters, with both groups having similar fan and cup ratios. Ultimately, our results suggest that the size at which bounced oysters are released to the benthos for grow out will dictate the usefulness of bouncing technique for reducing predation-related mortality.  相似文献   

Development of human-powered fish feeding machine for freshwater aquaculture farms of developing countries     

《Aquacultural Engineering》2020

Feeding the fishes rightly has been a problem for the fish farmers and developing suitable feeding devices is one of the most challenging problems faced by aquaculture engineers. Fish farmers of developing nations find manual feeding economical rather than opting for expensive mechanized feeding. In this study, a simple human-powered fish feeding machine which can economically solve the feeding issue in freshwater aquaculture, has been developed. The major parts of the feeder are cylindrical feed drums mounted on a pedal powered shaft, a catamaran barge, propeller and steering arrangements. When the operator pedals, the feed shaft rotates and the feed in the feed drums is metered through the metering holes provided in the feed drums. Human muscle power is used to power feeding operation as well as to propel the feeder. Since the device has been designed to utilize optimum human power for its entire operation, it is energy-efficient, environmental friendly and most importantly affordable. The developed device has been tested in laboratory and has been observed to be successfully operating in field condition while achieving the desired feed rate.  相似文献   

Numerical model of an aquaculture structure under oscillatory flow     

《Aquacultural Engineering》2020

Marine aquaculture is widely distributed in coastal areas. The aquaculture farms generate drag resistance to fluid motion and alter ambient hydrodynamics. Meanwhile, aquacultural structures are subjected to complex flow conditions including waves and currents. With the expansion to more open areas with severe flow field conditions, marine aquacultural structures face greater challenges and risks of damage. Culture unit is an important component of aquacultural structures and shows flexibility in both field observations and laboratory measurements. Underestimating or overestimating the drag resistance of culture units under the action of fluid flow can lead to damage risks or overdesign of the structure. A dynamic model is developed to estimate the deflection of flexible culture units and is incorporated into an aquacultural structure numerical model in this paper. Critical factors for safety as well as routine operation of aquacultural structures are considered including structural responses and mooring line forces. A suspended mussel long line system is taken as an example, and the results show that the calculated value (9.2 kN) of the maximum tension of the north mooring line is in good agreement with the measured data (9.8 kN) under the action of tide flow. The influence of different flow field parameters on structural dynamic responses is investigated. The numerical results indicate that decreasing wave height can reduce maximum mooring line tension and longitudinal and vertical motion amplitude of the main line. The maximum tension of the mooring line generally decreases with the increase of the angle between the main line and the inflow direction under the action of waves and tide flows. In structural design, the arrangement angle of structures can be determined according to the force calculation of mooring lines based on the numerical model. The spacing of culture units and the distance between adjacent long lines can be determined by referring to the motion calculation of structures to avoid damage due to intertwinement of structural components.  相似文献