The aquaculture supply chain in the time of covid-19 pandemic: vulnerability, resilience, solutions and priorities at the global scale

The COVID-19 global pandemic has had severe, unpredictable and synchronous impacts on all levels of perishable food supply chains (PFSC), across multiple sectors and spatial scales. Aquaculture plays a vital and rapidly expanding role in food security, in some cases overtaking wild caught fisheries in the production of high-quality animal protein in this PFSC. We performed a rapid global assessment to evaluate the effects of the COVID-19 pandemic and related emerging control measures on the aquaculture supply chain. Socio-economic effects of the pandemic were analysed by surveying the perceptions of stakeholders, who were asked to describe potential supply-side disruption, vulnerabilities and resilience patterns along the production pipeline with four main supply chain components: a) hatchery, b) production/processing, c) distribution/logistics and d) market. We also assessed different farming strategies, comparing land- vs. sea-based systems; extensive vs. intensive methods; and with and without integrated multi-trophic aquaculture, IMTA. In addition to evaluating levels and sources of economic distress, interviewees were asked to identify mitigation solutions adopted at local / internal (i.e., farm-site) scales, and to express their preference on national / external scale mitigation measures among a set of a priori options. Survey responses identified the potential causes of disruption, ripple effects, sources of food insecurity, and socio-economic conflicts. They also pointed to various levels of mitigation strategies. The collated evidence represents a first baseline useful to address future disaster-driven responses, to reinforce the resilience of the sector and to facilitate the design reconstruction plans and mitigation measures, such as financial aid strategies.publishe

The synergistic impacts of anthropogenic stressors and COVID-19 on aquaculture: a current global perspective

The rapid, global spread of COVID-19, and the measures intended to limit or slow its propagation, are having major impacts on diverse sectors of society. Notably, these impacts are occurring in the context of other anthropogenic-driven threats including global climate change. Both anthropogenic stressors and the COVID-19 pandemic represent significant economic challenges to aquaculture systems across the globe, threatening the supply chain of one of the most important sources of animal protein, with potential disproportionate impacts on vulnerable communities. A web survey was conducted in 47 countries in the midst of the COVID-19 pandemic to assess how aquaculture activities have been affected by the pandemic, and to explore how these impacts compare to those from climate change. A positive correlation between the effects of the two categories of drivers was detected, but analysis suggests that the pandemic and the anthropogenic stressors affect different parts of the supply chain. The immediate measurable reported losses varied with aquaculture typology (land vs. marine, and intensive vs. extensive). A comparably lower impact on farmers reporting the use of integrated multitrophic aquaculture (IMTA) methods suggests that IMTA might enhance resilience to multiple stressors by providing different market options under the COVID-19 pandemic. Results emphasize the importance of assessing detrimental effects of COVID-19 under a multiple stressor lens, focusing on areas that have already locally experienced economic loss due to anthropogenic stressors in the last decade. Holistic policies that simultaneously address other ongoing anthropogenic stressors, rather than focusing solely on the acute impacts of COVID-19, are needed to maximize the long-term resilience of the aquaculture sector.publishe

Compensatory growth after various levels of dietary protein restriction in rainbow trout, Oncorhynchus mykiss

This study was conducted to determine the effects of various levels of dietary protein restriction for 3weeks (phase 1) on compensatory growth, nutrient utilization, body compositions and organ indices of rainbow trout (Oncorhynchus mykiss) during a nine-week realimentation phase (phase 2). Five experimental treatments consisted of four protein restricted diets including 15, 22.5, 30 and 37.5% protein (RP15, RP22.5, RP30 and RP37.5 respectively) and the control diet 45% (C45). All diets were prepared to be isoenergetic at levels of 22.5MJkg -1 gross or 16.3MJkg -1 digestible energy. Each of five treatment groups was tried in triplicate groups of 75 fish with an average initial weight of 62.06±0.38g. Protein restriction in phase 1 linearly decreased specific growth rates of weight and length (SGR W and SGR L), body weight and length as well as feed utilization. The restriction induced a linearly increasing trend in protein retention efficiency, feed intake, organ indices such as viscera, pyloric caecum and hepato-somatic, whole body lipid and lipid/lean body mass whereas it induced a decrease in whole body moisture and protein at the end of phase 1. Protein restriction, except RP37, caused a significant increase in SGR W during phase 2 compared with C45, being most pronounced in the first 3weeks. Repeated measures ANOVA revealed a convergence in trajectories of ln body weight and length at the end of the experiment, suggesting that a complete catch up occurred in body mass and structure. There was also replenishment in distorted organ indices and body compositions, except protein which was still less in R15 than C45. More efficient utilization of feed and dietary protein by previously protein restricted fish during phase 2 appears to be the reason of the compensatory growth. At the end of the experiment, protein restriction was found to be effective in reduction of N loss. © 2012 Elsevier B.V..National Council for Scientific ResearchThis study was supported partly by The Scientific and Technological Research Council of Turkey under grant no. VHAG-2117 and the Mediterranean Fisheries Research Production and Training Institute, Antalya, Turkey . We would like to thank İ. Dal, M.A.T. Koçer, Ş. Ege, A. Yılayaz, Ö. Yeşilçimen, R. Uysal and F. Kardeş for their contributions over the experiment and laboratory analysis. -

Effect of various lengths of single phase starvation on compensatory growth in rainbow trout under summer conditions (Oncorhynchus mykiss) [Yaz koşullari{dotless}nda tek fazl{dotless} farkl{dotless} uzunlukta açl{dotless}k süreleri·ni·n gökkuşag {dotless} alabal{dotless}g {dotless}nda (oncorhynchus myki·ss) telafi· büyümesi·ne etki·si·]

This study was conducted to determine the effects of various lengths of starvation periods on following compensatory growth (CG) in rainbow trout under summer conditions (18.1°C and day length of 12.5-14.5 hours). Five treatments with triplicate tanks were as follows: control (C) fed to satiation over 84 days; one (S1), two (S2), three (S3), and four (S4) weeks of starvation; and then refeeding for the remaining eight weeks of the experiment. Starvation periods induced hyperphagia during refeeding but only S1 and S2 were able to catch up with C. Repeated measures of analysis of variance suggested a convergence in body mass but not in body length (structure). Organo-somatic indices of the starvation groups were significantly reduced at the end of starvation periods and restored to levels of the control fish within the first two weeks of the refeeding period. Broadly speaking, starvation longer than one week significantly reduced apparent digestibility of dry matter, lipid, and energy compared with the control group but did not affect protein and ash, and a complete recovery in the digestibility coefficients occurred within two weeks of satiation feeding. There was a linear increase in body moisture and a decrease in lipid and lipid/lean body mass ratio with the severity of starvation periods, but these divergences largely disappeared at the end of refeeding. During the starvation period, the protein synthesis rate (estimated using RNA/DNA ratio in the muscle and liver) reduced but in subsequent refeeding period, it increased in starved fish. The findings of the present experiment suggest that an application of single starvation episodes to elicit CG as a management tool in summer conditions should not be longer than two weeks. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey

Effects of mixed feeding schedules on growth performance, body composition, and nitrogen- and phosphorus balance in rainbow trout, Oncorhynchus mykiss

Background. Reducing feed cost and the pollution originating from feed have been principal matters in fish nutrition. Mixed feeding schedules have been proposed as one of the methods to reduce both of them and successfully tested in many fish species. The aim of the present study was to determine the mixed feeding schedules′ suitability for culture of rainbow trout. Materials and methods. Five different feeding schedules were tried by alternating the presentation of a low-protein (28.1%) diet (A) and a high-protein (49.9%) diet (B). The feeding schedules employed were 1A/1B, 1A/2B, 1A/3B, 2A/2B, and 2A/3B where the numerical values refer to the number of days each diet (A and B) was offered continuously. Fish given diets A and B continuously served as controls. Totally, seven dietary treatments were tested in triplicate for 10 weeks. Results. The fish maintained on the different mixed feeding schedules exhibited lower weight gain than those fed continuously on the high-protein diet (P < 0.05). The fish reared on schedule 1A/3B (1 day diet A alternated with 3 days diet B) had similar specific growth rate (SGR), feed conversation ratio (FCR), and protein efficiency ratio (PER) to those fed diet B continuously and was best among all mixed feeding schedules. However, the most cost-effective treatment was 2A/2B. In addition, this group compared to B resulted in significant increase and reduction of phosphorus retention and discharge, respectively (P < 0.05). The treatments significantly effected body moisture, fat- and ash levels (P < 0.05), but not protein. Conclusion. The study shows that mixed feeding schedules are promising for use in rainbow trout culture as they result in feed cost saving and reduced phosphorus discharge in the effluents

Effects of dietary zeolite (clinoptilolite) levels on growth performance, feed utilization and waste excretions by gilthead sea bream juveniles (Sparus aurata)

Natural zeolites have been increasingly used in terrestrial animal and freshwater fish diets as a growth and health promoter, but few studies have considered marine fish. Therefore, this study was planned to investigate the effects of dietary zeolite (clinoptilolite) incorporation on growth, feed and nutrient utilizations, whole body composition, waste excretions, intestinal morphology, fillet iron (Fe) and aluminum (Al) accumulations in juvenile gilthead sea bream (Sparus aurata). In the experiment, zeolite was included at 0 (Z0, control), 10 (Z10), 20 (Z20), 30 (Z30) and 40. g/kg (Z40) in a commercial sea bream diet and fed to fish with an initial weight of about 9.1. g for 10 weeks. Dietary zeolite treatments had a significant increasing effect on final weight (linear, P=0.046; quadratic, P=0.002) and specific growth rate (SGR) (linear, P=0.057; quadratic, P=0.010). Feed conversion efficiencies (FCE) of fish were linearly improved (linear, P=0.013) whereas PER increased both linearly (linear, P=0.033) and quadratically (quadratic, P=0.005). Supplemental zeolite did not affect body moisture or lipid but there was a trend for an increase (linear, P0.10). No differences in ADCs for dry matter, protein and lipid were detected but ADCs for energy had a quadratic trend (P=0.068). A trend for a decrease in total and dissolved nitrogen (N) losses was detected as the level of zeolite increased in the diet (quadratic, P=0.071 and 0.089 respectively). Anterior intestinal folds and gut length did not change with increasing zeolite levels but posterior intestinal folds decreased (linear, P=0.013; quadratic, P=0.023) and gut index had a quadratic trend (P=0.081). Optimum dietary inclusion level of zeolite was estimated as 27.1. g/kg based on the maximization of SGR, PER and FCE values. © 2014 Elsevier B.V.TAGEM/HAYSUD/2011/09/01/01The General Directorate of Agricultural Research and Policy , Ministry of Food, Agricultural and Livestock , and Academic Research Projects Unit, Cukurova University, Turkey supported this research under grant no TAGEM/HAYSUD/2011/09/01/01 and SÜF 2010 D 04 respectively. The authors wish to express their gratitude to Yılmaz Emre, Aslıhan Polatoğlu and Talip Özgen for their supports during the study, and Gordes Zeolite, for generously providing the zeolite material

Hatchery performance in a major rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) seed production area of Turkey

This study aims to determine the production characteristics and performance of rainbow trout hatcheries in Seydikemer, Muğla, Turkey where over half of the total production of eyed eggs and juveniles take place. For this purpose six hatcheries with different production scales were selected and coded A, B, C, D, E and F (with capacities of 60, 15, 5.6, 4, 0.95 and 0.6 million juveniles per year, respectively). From each hatchery, 20 females were selected and their egg qualities (egg number, diameter and weight, fertilization, eyed egg, hatching, swim-up fry and survival rates at 120 days after hatching) and juvenile growth rates were monitored until the 120th day after hatching under each farms own conditions. The sperm characteristics of 10 broodstock males from each hatchery were also examined. Although fertilization and eyed egg rates were similar among the farms, hatching, swim-up fry, and survival rates at the 120th day after hatching differed significantly. The average eyed egg, hatching and survival rates (calculated from selected 20 females) were 72, 55, and 32%, respectively. While sperm characteristics except duration of motility (s), were significantly different among the farms, average sperm concentration (per ml), motility (%) and duration of motility (s) in the region were 11.8 × 109, 55.3, and 56.4, respectively. The best hatchery performance was observed in Farm A because of better records and management applications than in the other farms. © 2016 Blackwell Verlag Gmb

Effects of natural and synthetic pigments in diets on flesh coloration and growth of rainbow trout (Oncorhynchus mykiss W.)

The desired pink to red color of rainbow trout flesh (Oncorhynchus mykiss W.) can be obtained by adding carotenoids to the fish diet. This study was conducted to determine the effects on growth and color retention of natural pigments (30 ppm red pepper meal, 60 ppm red pepper meal, 30 ppm shrimp by-products meal, 60 ppm shrimp by-products meal), synthetic carotenoids (30 ppm astaxanthin, 60 ppm astaxanthin), and a control group (no added pigment). Duplicates of each of the seven treatments were reared for three months. The best specific growth rates were obtained with 30 ppm astaxanthin (0.83%) and 60 ppm red pepper meal (0.84%); the lowest was in the control (0.54%). The lowest food conversion ratio was obtained with 30 ppm astaxanthin (1.38) and highest in the control (2.23; p<0.05). Visual coloration values ranged from 14.46±0.23 in the 30 ppm astaxanthin group to 11.55±0.25 in the control. Retention coefficients ranged from 6.63 in the 30 ppm astaxanthin group to 1.79 in the 60 ppm shrimp by-products meal (p<0.05). Tristimulus chromometer a values ranged from 0.87±0.47 in the control to 6.96±0.47 in the 60 ppm astaxanthin treatment, b values from 10.94±0.27 in the control to 12.90±0.27 in the 60 ppm red pepper meal treatment, and L values from 46.81±0.50 in the 60 ppm astaxanthin group to 54.57±0.26 in the control (p<0.05)