Fitting growth with the von Bertalanffy growth function: a comparison of three approaches of multivariate analysis of fish growth in aquaculture experiments

Three approaches for multivariate analysis of fish growth in aquaculture experiments with Nile tilapia (Oreochromis niloticus niloticus L.) based on the von Bertalanffy growth curve are presented and compared. The approaches are: an extended Gulland‐and‐Holt (GH) plot, a forced extended GH plot and a multilinear regression analysis for the growth parameter K. All three models provide valuable insight into the major environmental factors influencing the daily growth rate and explain 28–46% of the variance of the observed daily growth rate of the used data set. For all three methods, the modelled parameter is significantly related to the net yield of Nile tilapia and can, therefore, be used for the predictive modelling of management scenarios. The extended GH plot loads the influence of environmental parameters upon L_∞, while the forced extended GH plot and Direct fitting of K load the influence on the growth parameter K. The latter is more in the tradition of aquaculture research. But the forced extended GH plot and Direct fitting of K can only be applied if L_∞ of the cultured species is known, as the selected L_∞ influences the variance in the regression variables.     

Stringency of environmental regulation and aquaculture growth: A cross-country analysis

During the last three decades, aquaculture has been the fastest growing animal-food-producing sector in the world, accounting for half of the present seafood supply. However, there is a significant growth disparity among aquaculture-producing countries. The reasons why some countries have achieved remarkable growth in aquaculture while others have stagnated or even declined have not been determined. In this article, we investigate whether environmental regulations have an impact on aquaculture growth. Using a cross-country regression analysis, we show that stringent environmental regulations are negatively related to aquaculture growth, whereas GDP growth has a positive effect. Countries often face a difficult balancing act between growth and environmental considerations when devising regulations. Our empirical results suggest that stricter environmental regulations in developed countries have contributed to lower growth rates and that these countries are falling behind emerging and developing economies that have more lenient environmental regulations.     

A partial-reuse system for coldwater aquaculture

A model partial-reuse system is described that provides an alternative to salmonid production in serial-reuse raceway systems and has potential application in other fish-culture situations. The partial-reuse system contained three 10 m³ circular ‘Cornell-type’ dual-drain culture tanks. The side-wall discharge from the culture tanks was treated across a microscreen drum filter, then the water was pumped to the head of the system where dissolved carbon dioxide (CO₂) stripping and pure oxygen (O₂) supplementation took place before the water returned to the culture tanks. Dilution with make-up water controlled accumulations of total ammonia nitrogen (TAN). An automatic pH control system that modulated the stripping column fan ‘on’ and ‘off’ was used to limit the fractions of CO₂ and unionized ammonia nitrogen (NH₃---N). The partial-reuse system was evaluated during the culture of eight separate cohorts of advanced fingerlings, i.e., Arctic char, rainbow trout, and an all female brook trout × Arctic char hybrid. The fish performed well, even under intensive conditions, which were indicated by dissolved O₂ consumption across the culture tank that went as high as 13 mg/L and fish-culture densities that were often between 100 and 148 kg/m³. Over all cohorts, feed conversion rates ranged from 1.0 to 1.3, specific growth rates (SGR) ranged from 1.32 to 2.45% body weight per day, and thermal growth coefficients ranged from 0.00132 to 0.00218. The partial-reuse system maintained safe water quality in all cases except for the first cohort—when the stripping column fan failed. The ‘Cornell-type’ dual-drain tank was found to rapidly (within only 1–2 min) and gently concentrate and flush approximately 68–88% (79% overall average) of the TSS produced daily within only 12–18% of the tank’s total water flow. Mean TSS concentrations discharged through the three culture tanks’ bottom-center drains (average of 17.1 mg/L) was 8.7 times greater than the TSS concentration discharged through the three culture tanks’ side-wall drains (average of 2.2 mg/L). Overall, approximately 82% of the TSS produced in the partial-reuse system was captured in an off-line settling tank, which is better TSS removal than others have estimated for serial-reuse systems (approximately 25–50%). For the two cohorts of rainbow trout, the partial-reuse system sustained a production level of 35–45 kg per year of fish for every 1 L/min of make-up water, which is approximately six to seven times greater than the typical 6 kg per year of trout produced for every 1 L/min of water in Idaho serial-reuse raceway systems.     

A design study on the optimal water refreshment rate in recirculating aquaculture systems

Refreshment (make-up) water is used in recirculating aquaculture systems (RAS) mainly to purge off-flavors, to add alkalinity and sometimes for temperature control. Alternatively, alkalinity may be added by means of a chemical base and heat may be supplied by a heating system. The objective of this study is to show how the optimal (minimizing cost) mix of the three controls: water, base and heat, can be found for given temperatures and water prices.The optimal solution varies over the temperature space and also depends on the price of water. For conditions at Eilat, Israel (on the Red Sea), using supplementary heating to maintain a constant temperature may become prohibitively expensive. If heating is given up, the remaining choice is between the supply of alkalinity via the refreshment water and adding a base. The supply of alkalinity with the water requires 2.0 m³[water]/kg[feed], much more than the minimum refreshment rate required to purge off-flavors, which is thought to be 0.3 m³[water]/kg[feed]. If the price of water is more than 0.03 USD/m³, the use of sodium bicarbonate for alkalinity control is justified.     

鱼类生长的幂指数生长方程

研究鱼类生长往往需要选择适当的数学模型来处理实际数据以表征生长的某些特点 ,或用于比较生长速度 ,或用于消除随机因素的影响 ,使生长曲线圆润化 ,以显示生长的趋势。其中受到高度重视并被广泛应用的是贝特朗菲方程 (ｖｏｎＢｅｒｔａｌａｎｆｆｙｅｑｕａｔｉｏｎ)。然而该模型在理论上有不足之处 ,适用范围也不够理想。为此 ,取陆文杰[1] 对林木生长研究中提出并命名的数学模型———幂指数生长方程 ,用大量的鱼类生长数据[2 -6] 验证结果 ,证实该方程比贝氏方程更适于研究鱼类生长规律。1　材料与方法1 .1　数据及其来源共 12 4份 ,75…     

基于工厂化养殖的圆斑星鲽生长初步研究

为了解工厂化养殖条件下圆斑星鲽(Verasper variegates)幼鱼的生长特性,在水温9.0~22.5℃时,对圆斑星鲽幼鱼的体长和体质量进行了近1年的测定分析。结果显示:平均体长为(9.29±0.16)cm、平均体质量为(22.11±1.03)g的5月龄左右的圆斑星鲽幼鱼,经1年的人工饲养后平均体长为(36.15±0.36)cm、平均体质量为(647.97±12.54)g,体长与日龄之间呈线性关系L=1.492x+2.350,R2=0.966,其体长平均瞬时增长率为0.12,体长平均月增长量为2.44 cm;体质量与日龄之间呈指数关系Wgc=9.380 e0.264x,R2=0.960,其体质量平均瞬时增长率为0.31,体质量平均月增长量为56.92 g;体长与体质量的回归曲线Wwl=0.030x2.971,R2=0967,幂指数约等于3,表明体质量与体长的立方呈正相关系,为等比生长类型。在工厂化养殖条件下,圆斑星鲽幼鱼的体质量增长量、体质量相对生长率、体质量瞬时生长率与水温变化大体一致,16~18℃时增重较快;反映幼鱼生长阶段的生长指标、生长系数波动较大,没有显示出规律性;体质量与体长呈显著相关,处于负异速生长阶段。     

水产养殖鱼类生长性状研究进展

生长性状是水产养殖鱼类最重要的经济性状之一,对水产养殖业的发展意义重大。通过以不同的养殖鱼类为对象,大量的研究结果表明,鱼类生长主要受环境、基因,以及基因与环境相互作用的影响,具体为:(1)环境是生长性状调控的外因,其对生长的影响一般呈现出剂量效应的规律。温度、光照、营养等主要环境因子的过量和不足均可能对鱼类生长产生不利影响,因此,寻求最优条件是制定最佳养殖环境的终极目标,人为调控多种环境因子在现代水产养殖业中具有重大的应用潜力。(2)基因是生长性状调控的内因,其对生长的影响很大程度上表现出因果效应的关系。某些基因的单碱基核苷酸多样性、基因结构变异、染色体倍性变化,以及转基因等都表现出对鱼类生长产生统计显著性的影响。鉴于生长是多基因控制的复杂数量性状,寻找主效基因并在选育中加以利用是改良生长性状的重要基础。高通量测序技术在生长相关候选基因的筛选以及辅助分子育种方面展现出强大的优势。(3)基因与环境相互作用的影响主要来自基因型对不同环境条件的适应性,具有特异性和复杂性的特点,因此目前对其量化研究非常有限。但在制定大规模商业育种计划之前,考虑基因与环境相互作用具有重要意义。综上所述,充分理解环境、基因,以及基因与环境相互作用对水产养殖鱼类生长的影响能更好地对其生长性状加以利用,从而最大限度地节约养殖成本和发挥生态效益。     

高效藻类塘技术及其在水产养殖中的研究与应用

介绍了高效藻类塘(HRAP)的技术原理,分析了国内外在高效藻类塘方面的研究进展以及在水产养殖方面的研究应用情况,认为高效率藻塘技术是净化养殖富营养化水体的一种有效途径。应用高效藻类塘净化养殖水体,应充分利用养殖生态系统中的能量和物质转化关系,并与生态工程化技术、藻菌固定化技术、微生物技术等相结合。     

A site management system for shellfish aquaculture

Abstract

A production management and planning system has been developed for large‐scale hanging culture operations. The relational database was designed to provide a fast, reliable and versatile tool for managing large volumes of production data at a scallop aquaculture site. The application development process is described, starting with the set of management decisions to be supported by the software. Best practices used for data structure design included normalization and entity‐relationship diagramming. The process‐based design resulted in visually consistent and user‐friendly interfaces which minimize data entry errors. An integrated forecasting model, based on seasonal exponential smoothing, extrapolates stagewise mortalities and flows calculated from the database. Typical simulation results demonstrate how forecasts provide insight into the grow‐out dynamics for capacity planning, manpower planning, and dealing with seasonal fluctuations in the yields. The software generates daily production reports, weekly harvesting schedules and long‐range planning information.     

中国水产养殖种类组成、不投饵率和营养级

根据1950–2014年水产养殖种(类)有关统计和调研数据,并在对养殖投饵率、饲料中鱼粉鱼油比例、各类饵料(配合饲料、鲜杂鱼/低值贝类/活鱼、天然饵料等)营养级等基本参数进行估算的基础上,研究分析了中国水产养殖种类组成、生物多样性、不投饵率和营养级的特点及其变化。结果表明:中国水产养殖结构相对稳定,变化较小,其显著特点是种类多样性丰富、优势种显著、营养层次多、营养级低、生态效率高、生物量产出多。其中:(1)养殖种类296个、品种143个,合计为439个。种类组成区域差异明显,淡水养殖鱼类占绝对优势,如2014年草鱼、鲢鱼、鳙鱼、鲤鱼、鲫鱼和罗非鱼排名前6个种类的养殖占淡水养殖产量69.6%,其次为甲壳类、其他类、贝类及藻类,而海水养殖则以贝藻类为主,如2014年牡蛎、蛤、扇贝、海带、贻贝和蛏6个种(类)的养殖占海水养殖产量71.3%,其次为甲壳类、鱼类及其他类;(2)养殖种类多样性特征显著,与世界其他主要水产养殖国家相比,独为一支,具较高的多样性、丰富度和均匀度,发展态势良好;(3)由于养殖方式从天然养殖向投饵养殖转变,不投饵率呈明显下降趋势,从1995年90.5%降至2014年53.8%(淡水35.7%,海水83.0%),但与世界平均水平相比,仍保持较高的水准;(4)与世界相比,营养级低且较稳定。由于配合饲料的广泛使用及其鱼粉鱼油使用量减少,近年营养级略有下降,从2005年较高的2.32降至2014年2.25(淡水2.35,海水2.10)。营养级金字塔由4级构成,以营养级2为主,近年占70%,表明其生态系统有较多的生物量产出。中国水产养殖未来发展需要遵循绿色、可持续和环境友好的发展理念,探讨适宜的、特点各异的新生产模式,发展以养殖容量为基础的生态系统水平的水产养殖管理,建设环境友好型的水产养殖业,为保障国家食物安全、促进生态文明建设作出更大贡献。     

一种新型水产饲料添加剂--酵母细胞壁

酵母细胞壁是一种新型的环保型饲料添加剂,在水产养殖中应用十分广泛。大量试验表明,它能影响肠道微生态平衡,增殖肠道有益菌,抑制有害菌,提高动物免疫机能,促进新陈代谢,从而提高动物的生产性能和经济效益。综述了酵母细胞壁的组成成分、免疫机理及其在水产养殖中的应用情况,并展望了酵母细胞壁作为水产饲料添加剂的应用前景。     

Optimization of fertilization rate for maximizing periphyton production on artificial substrates and the implications for periphyton-based aquaculture

The effects of four rates of application of fertilizer, with cow manure (3000 kg ha⁻¹), urea (100 (kg ha⁻¹) and triple super phosphate (TSP) (100 kg ha⁻¹) (treatment F)), treatment F × 0.5 (treatment 0.5F), treatment F × 1.5 (treatment 1.5F) and treatment F × 2 (treatment 2F), on periphyton, plankton and water quality in tropical freshwater ponds were studied. The highest periphyton biomass in terms of dry matter (3.27 mg cm⁻² substrate), ash-free dry matter (2.06 mg cm⁻² substrate) and chlorophyll a (7.49 µg cm⁻² substrate) developed in treatment 1.5F. The ash content of periphyton was lower in treatment 1.5F (38% of dry matter) than in other treatments (57–66% of dry matter). Total ammonia and chlorophyll a of water increased with fertilization rate. Treatment 1.5F (cow manure, urea and TSP at rates of 4500, 150 and 150 kg ha⁻¹ respectively) appears to be the optimum, yielding high quantity and quality periphyton. By supplying a substrate area for periphyton equivalent to the pond surface, it was estimated that this level of fertilization could support a fish production of around 5000 kg ha⁻¹ y⁻¹, without recourse to supplementary food.     

Effects of flow rate on growth performance and welfare of juvenile turbot (Scophthalmus maximus L.) in recirculating aquaculture systems

The effects of flow rate on growth and welfare of juvenile turbot (Scophthalmus maximus L.) were investigated in the present study. Fish with same initial weight (102.5 ± 10.6 g) were subjected to four flow rates, equalling to 0.5, 1, 1.5 and 2 tank volumes per hour in twelve 392 L tanks during 80 days. Results showed that specific growth rate of turbots increased (0.40–0.58% day^?1) significantly with promoted flow rate (P < 0.05). Total ammonia nitrogen, nitrite nitrogen, unionized ammonia nitrogen, chemical oxygen demand, total bacteria and total vibrio in tanks were affected significantly by flow rate and accumulations were found in low rate (200 L h^?1) (P < 0.05). Free carbon dioxide increased significantly with the increased flow rate and ranged between 4.5 and 13.5 mg L^?1 (P < 0.05). Both superoxide dismutase activity and lysozyme activity increased significantly with flow rate (P < 0.05), with ranges of 108.51–131.57 U mL^?1 and 551.81–869.28 U mL^?1. Serum cortisol showed reversed tendency and ranged between 7.39–19.26 ng mL^?1. The principal components analysis suggested that increased flow rate promoted fish welfare. It was concluded that increased flow rate promoted the growth of juvenile turbot, possibly explained by fish welfare differences in combination of health, water quality and serum parameters.     

A review of production frontier analysis for aquaculture management

Abstract

This paper examines recent advances in production economics with special reference to efficiency measurement using production frontiers and its implications for aquaculture management. Compared with agriculture and other industries, the use of production frontiers in aquaculture is still very limited. However, in recent years several frontier applications in aquaculture have appeared in the literature, suggesting potential applications of these techniques in aquaculture. A synopsis of stochastic frontier production function model and data envelopment analysis (DEA), the two most popular approaches to efficiency measurement, is presented, followed by a review of recent frontier studies in shrimp, carp and tilapia production. The paper concludes with a brief discussion of future development and prospects of frontier applications for aquaculture management.     

A future vision for disease control in shrimp aquaculture

Aquaculture is the fastest‐growing animal production sector, and shrimp production already exceeds that of the capture fishery. Viruses and bacteria account for the majority of disease losses for shrimp farmers. Viral pandemics in the mid 1990s and, more recently, a bacterial pandemic from 2009 to 2015 have led to the conclusion that future, sustainable shrimp aquaculture will depend on the development of more efficient, biosecure production facilities that cultivate specific pathogen‐free (SPF) shrimp, genetically improved for growth and disease tolerance or resistance. Major requirements for development, maintenance, and use of SPF stocks in aquaculture are effective pathogen surveillance and disease prevention methods. When protective measures fail and diseases occur in production ponds, there are currently only a few approved and practical therapeutic methods available for use with bacterial pathogens and none so far for viral pathogens. To improve existing methods of prevention and therapy and to develop new ones, research is being carried out on the nature of shrimp–pathogen interactions. Promising results have been obtained at the laboratory level for possible applications involving the use of immunostimulants for “immune priming” or “trained immunity” of RNA interference and of endogenous viral elements. Some of these promising new directions are discussed.     

Modelling fish growth: multi-model inference as a better alternative to a priori using von Bertalanffy equation

The common practice among researchers who study fish growth is to a priori adopt the von Bertalanffy growth model (VBGM), which is the most used and ubiquitous equation in the fisheries literature. However, in many cases VBGM is not supported by the data and many species seem to follow different growth trajectories. The information theory approach frees the researcher from the limiting concept that a ‘true’ growth model exists. Multi‐model inference (MMI) based on information theory is proposed as a more robust alternative to study fish growth. The proposed methodology was applied to 133 sets of length‐at‐age data. Four candidate models were fitted to each data set: von Bertalanffy growth model (VBGM), Gompertz model, Logistic and the Power model; the three former assume asymptotic and the latter non‐asymptotic growth. In each case, the ‘best’ model was selected by minimizing the small‐sample, bias‐corrected form of the Akaike information criterion (AIC_c). To quantify the plausibility of each model, the ‘Akaike weight’w_i of each model was calculated. Following a MMI approach, the model averaged asymptotic length for each case was estimated, by model averaging estimations of interpreting Akaike weights as a posterior probability distribution over the set of candidate models. The VBGM was not selected as the best model in 65.4% of the cases. Most often VBGM was either strongly supported by the data (with no other substantially supported model) or had very low or no support by the data. The estimation of asymptotic length was greatly model dependent; as estimated by VBGM was in every case greater than that estimated by the Gompertz model, which in turn was always greater than that estimated by the Logistic model. The percentage underestimation of the standard error of , when ignoring model selection uncertainty, was on average 18% with values as high as 91%. Ignoring model selection uncertainty may have serious implications, e.g. when comparing the growth parameters of different fish populations. Multi‐model inference by model averaging, based on Akaike weights, is recommended as a simple and easy to implement method to model fish growth, for making robust parameter estimations and dealing with model selection uncertainty.     

基于生长和死亡参数变化的官井洋大黄鱼资源现状分析

依据2010—2011年福建官井洋水域渔业资源监测调查资料,对2 098尾大黄鱼的体长、体质量、生长、性腺进行测定。据此,利用von Bertalanffy生长方程和死亡参数分析官井洋大黄鱼资源现状,并讨论了拐点年龄,临界年龄等渔业生物学特征。结果表明,目前官井洋大黄鱼平均体长132.6 mm,优势体长组为110～150 mm,占55.96%;平均体质量45.1 g,优势体质量组为10～50 g,占61.77%,大黄鱼幼鱼和补充群体已成为渔业生产的主要捕捞对象。大黄鱼体长—体质量间的关系式为W=2.001×10-5L3.006。用ELEFAN技术拟合的von Bertalanffy生长方程参数分别为L∞=385.4 mm、k=0.43及t0=-0.32a,拐点年龄为2.2龄。对照20世纪80年代福建近海海域大黄鱼群体L∞值从555.4 mm下降到现在的385.4 mm,拐点年龄由2.97下降到2.2,均表明当今大黄鱼群体小型化且低龄化严重。生长系数k由0.36增长到0.43表明大黄鱼的生长速度加快。总死亡系数(Z)为3.12,自然死亡系数(M)为0.45,捕捞死亡系数(F)为2.67,资源开发率(E)为0.856。大黄鱼M值出现上升,可能与福建近海环境质量下降有关,而高强度的捕捞促使大黄鱼捕捞死亡系数由0.84上升到2.67,说明大黄鱼资源已经处于过度开发状态。在官井洋大黄鱼现行资源状态下,应努力降低捕捞死亡水平,保护大黄鱼生存环境,而对目前以小型化和低龄化为主的大黄鱼群体,建议以控制大黄鱼的开捕年龄(t0)为主。     

5种壳色长牡蛎不同组织常规营养成分分析与评价

为探究DNA甲基化在长牡蛎性腺发育中的表观遗传调控机制,对长牡蛎Htatip2的同源性、系统进化、组织表达以及三倍体性腺可育型和不育型不同发育时期的基因表达和DNA甲基化谱进行了研究。结果显示,长牡蛎Htatip2的保守结构域与美洲牡蛎的Htatip2-like的保守结构域同源性最高。qPCR分析显示, Htatip2在各个组织中均有表达,其中在雌性性腺中的表达量最高。此外,该基因的表达量在可育型三倍体牡蛎性腺中随着性腺发育成熟而升高,在不育型三倍体牡蛎性腺中表达量变化不显著。BS-PCR分析显示,该基因的甲基化水平随着性腺发育成熟而降低,与基因表达水平成负相关性。双荧光素酶报告结果显示,甲基化的Htatip2启动子片段与未甲基化的片段相比,显著抑制了荧光素酶的活性。研究表明,长牡蛎Htatip2的DNA甲基化可能通过抑制基因表达参与了性腺成熟调控。本研究为表观遗传调控机制参与牡蛎性腺发育提供了重要参考依据。     

Effects of mechanical aeration on evaporation rate and water temperature in aquaculture ponds

Water temperature and water loss by evaporation were monitored in control ponds and in ponds with different rates of aeration (9.2, 18.4, 27.6 and 36.9 kW/ha). The mean decrease in water temperature at 70‐cm depth was greater than that at the surface in aerated ponds than in control ponds. The greater the aeration rate, the cooler was water, both at the surface and at 70 cm. Evaporation rates were found to increase with greater aeration rate. Water loss increased by 32%–92% over 24‐hr periods in ponds with one to four 0.37‐kW Air‐O‐Lator aerators, respectively. The nutrient‐enriched control pond was more turbid, had cooler surface and deep water temperature, and had greater evaporation loss than the control pond without nutrient addition and less turbid water. But, aeration did not increase turbidity. Aeration can increase water loss from ponds and result in lower water temperature. Although aeration should not be used excessively in order to conserve water and reduce production cost, it is essential for many types of feed‐based aquaculture.     

A review of genetic improvement in growth rate in redclaw crayfish Cherax quadricarinatus (von Martens) (Decapoda: Parastacidae)

This paper provides a review and summary of strain comparison and selective breeding work carried out on redclaw crayfish Cherax quadricarinatus (von Martens) at the Queensland Department of Primary Industries, Freshwater Fisheries and Aquaculture Centre, Walkamin. Redclaw crayfish are a highly marketable, environmentally tolerant, freshwater crayfish with a moderately fast, but variable, growth rate. Five strains of the species were assessed morphologically and in terms of age at maturity. A non‐replicated production trial was also carried out before two strains, from the Gilbert and Flinders rivers in North Queensland, were chosen to be part of an experimental selective breeding programme for improved growth. Initially, 14 families of each strain were randomly mated and grown out. At this point, a size‐related selection took place, with the largest animals from each family forming a selected line, and individuals from around the mean forming a control line. Within‐family selection and reciprocal mating between families was performed. Data were collected after each of two generations of growout and analysed by analysis of variance. Significant differences (P < 0.05) were measured between strains, sexes and between selected and control lines. Selected individuals grew 9.5% faster than the controls. Recommendations for selective breeding research involving freshwater crayfish are presented.