COMPARISON OF SOME FISH SORTING TOOLS FOR GRADING Clarias .
ORIGINAL ARTICLE/ORİJİNAL ÇALIŞMAFULL PAPERTAM MAKALECOMPARISON OF SOME FISH SORTING TOOLS FORGRADING Clarias gariepinus FINGERLINGSUgwem GABRIEL1, Ojo AKINROTIMI2, Yusuf MOMOH11Department of Fisheries and Aquatic Environment, Faculty of Agriculture Rivers State University of Science andTechnology P.M.B. 5080, Port Harcourt, Rivers State Nigeria2African Regional Aquaculture Centre/Nigerian Institute for Oceanography and Marine Research P.M.B. 5122, PortHarcourt, Rivers State Nigeria.Received: 06.02.2015Corresponding author:Accepted: 09.11.2015Ojo AKINROTIMI, African Regional Aquaculture CenterPublished online: 04.04.2016Nigerian Institute for Oceanography and Marine ResearchP.M.B 5122, Port Harcourt, Rivers State, NigeriaE-mail: ojoakinrotimi@yahoo.comAbstract:Over 200,000 of Clarias gariepinus two-week oldhatched fry were sorted at different ages i.e 2, 3, 4, 5and 6 weeks using nine differet grading tools, namelyDipnet (DN), grading cage (GC), hang grading net(HGN), meshed box (MB), plastic basin (PB), plywood box (PWB), sorting table (ST), woven basket(WB), and wood grading panel (WGP). The resultfrom the study indicated that sorting table (ST), gradesfaster in all the age of the fry, having the highest number of graded fry. In all the ages, plastic basin (PB)consistently had the lowest. The highest mortality values were observed in sorting table (ST) in all the agesof fish sorted while the lowest values were recorded ingrading cage (GC). The success of the grading cage(GC) was that it grades more efficiently through thebottom unlike other sorting tools which gradel throughits sides. Clarias gariepinus fry between the age of 2and 4 weeks is best graded using the grading cage forhigh survival rate and sorting table is best used withfish from the age of 4 weeks and above.Key words: Aquaculture, Grading tools, Size diversity, Fingerlings, Clarias gariepinusJOURNAL OF AQUACULTURE ENGINEERING AND FISHERIES RESEARCHE-ISSN 2149-02362(3): 109-118 (2016) doi: 10.3153/JAEFR16013 2015-2016 ScientificWebJournals (SWJ)109
Journal of Aquaculture Engineering and Fisheries ResearchGabriel et al., 2(3): 109-118 (2016)Journal abbreviation: J Aquacult Eng Fish ResIntroductionAquaculture in Nigeria has a history of at least fourdecades, with spectacular growth recorded in thelast few years (AIFP, 2010; Akinrotimi et al.,2011a). According to Gabriel et al. (2007a) the fullpotential of aquaculture began to be realizedrecently when it became obvious that the everincreasing demand for fish cannot be met fromcapture fisheries alone. Therefore, reducing thewidening gap between fish demand and supply andachieving the ultimate goal of self-sufficiency infish production is the major target of aquaculture asan enterprise (Ugwumba and Ugwumba, 2003).The steadily growing importance of fish farminghas compelled improvements in the technologiesnecessary for securing the initial and basic requirements for productive aquaculture; namely theproduction of fish seed for stocking (Akinrotimi etal., 2011b). Fish culture today is hardly possiblewithout the artificial propagation of fish seeds ofpreferred cultivable fish species (Akinrotimi et al.2013a). The need for the production of quality fishseed for stocking the fish ponds and natural waterbodies has indeed increased steadily (Dada, 2006).Artificial propagation methods constitute the majorpracticable means of providing enough quality seedfor rearing in confined fish enclosure waters such afish ponds, reservoirs and lakes (Conceicao et al.,2005; Akinrotimi et al., 2011c). The production ofmarketable fish fingerlings or juveniles into rearingenvironment that assures optimum and rapid growthto allow harvest in the shortest possible time. Thefish farmer has to obtain adequate number of youngfish to meet “his” production goals. The possibilities of obtaining fish seed in adequate numbersfrom natural source is rather limited. Even thespawners which, reproduces successfully inconfined enclosures are propagated artificially(Madu et al., 2004; Gabriel et al., 2007b). Apartfrom being able to obtain quality seed, the artificialpropagation technique can also be used to developstrains superior to their ancestors by the methods ofselective breeding and hybridization. Depending onthe perfection of the system, at least 65% of theeggs produced can be raised to viable fingerlings asagainst less than 1% survival rate in natural spawning. It is through this method that out of seasonsupplies of fingerlings are achieved (Dada et al.,2002).110For a fish production through aquaculture to meetthis projected or potential demand for fish in thecountry there is the need to establish a pool offingerlings annually (Ezenwa et al., 1990; Dada andWonah, 2003). According to Ayinla (1991), thereare generally two sources of fingerlings: wildcollection and hatchery production. It is obviousthat the supply from the wild is unreliable; hencesupply of sufficient fingerlings depends on hatcheryproduction. Fish hatchery is the bedrock uponwhich true and sustainable fish farming is built(Nwadukwe and Ayinla, 1993; Ugwumba et al.,1998; Anyanwu et al., 2007).The major problem faced by the hatcheries operators’ center on the technicalities of handling fish fryon farms (Zaki et al., 2004). Grading of fishfingerlings is one of the most common managementpractices in fish farming that a serious hatcheriesoperator need to know in order to be able tomaintain almost the same quantity of fish from fryto fingerlings stage. For example, some hatcheryoperators do have up to 500,000 fry at early stage,but before getting to fingerlings stage a lot of themwould have been lost as a result of cannibalismwhich is more prevalent among the clariids (Ayinlaand Nwadukwe, 2003). Hence the need for them tobe sorted (graded). Sorting of fish according toFAO (2000), involves separating a mixed group offish into different species, sexes, and sizes.Significant size diversity within fish speciesrequires that they be sorted. The main goal of thistechnique is to obtain maximum weight gain by allindividuals and to increase their survival rate whichresult in obtaining the maximum biomass (Baarduikand Jobling 1990; Kamstra 1993, Sunde et al.,1998). Sorting separates small and big fish fingerlings, thus minimizing the effect of inter individualinteraction (Jobling, 1995). However, frequentsorting of the species sometimes can cause decreased growth rates as a result of stress (Baarduikand Jobling, 1990; Jamu and Ayinla, 2003).Clarias gariepinus belong to the family clariidaeand it is most popular fish for culture in Nigeria,next to the tilapia fishes (FAO, 1997; Adeogun etal., 2007). They are characterized by highlyvariable individual growth rates. During earlydevelopmental stages this leads to intensified
Journal of Aquaculture Engineering and Fisheries ResearchGabriel et al., 2(3): 109-119 (2016)Journal abbreviation: J Aquacult Eng Fish Rescannibalism (Barki et al., 2000). In order tominimize losses at this early stage the stock must besorted frequently. According to Kestemont andMelarde (2000) sorting of fish fingerlings intovarious size groups normally leads to equalizationof the growth rates in the reared groups. Thissuggests that the growth rate of particular specimenis not only determined genetically, but that thephenomena of domination and hierarchies in fishstocks might also play some roles (Melard et al.,1995). According to Wedemeyer (1996), young fishare under significant stress due to increased interindividual interactions such as high stockingdensity, competition for food and space, that theyare costantly exposed to, this leads to differentialrate of growth among individuals of the same age(Carmichael, 1994) necessitating the need forsorting.However, report on the assessment of differentsorting tools for grading of Clarias gariepinusfingerlings, a popular culturable fish in Nigeria isessential for the sustainability of aquacultureindustry, thus necessitated the need to carry out thiswork.Materials and MethodsThe study was carried out in a privately ownedfarm, located at Kpite, in Tai Local GovernmentArea of Rivers State, Nigeria under actual farmingconditions. The Clarias gariepinus frys used for theexperiment were obtained from the hatchery unit ofthe farm. The fish were observed to be active andapparently healthy.Experimental ProcedureThe experimental procedure was adapted followingthe method described by Ezenwa et al. 1990, whoproposed a maximum number of 1000fries persorting tool in grading of 2 weeks old catfish, C.gariepinus and which can subsequently be reducedas the fries grows older. The experiment started bygrading a total number of 9,000 fries (two weeksold), consisting of 1000 fries per each of the ninegrading tools, this was reduced, to 7,200 fries (3weeks old) by the second week, consisting of 800fries per each of the nine grading tools. This wasfurther reduced to 5,400 fries (4 weeks old) duringthe third week at 600 per each of the sorting tool.At week 4 however, 3,600 fries (5 weeks old) weregraded at 400 per each sorting tool. Lastly 1, 800fries (6 weeks old) were graded at week 5 at 200per each sorting tool. In all, the experiment lastedfor a period of five weeks, grading over 200,000 fryby using 9 different grading tools for each stage offry development.Method of Counting of Experimental FishIn counting the number of fry, an estimationmethod was used. This was done by using a strainerof 2.0g, which normally contain 1,800 fry. Theweight of the fry was then determined using theformulaW2 - W1 W3WhereW1 Weight of strainerW2 Weight of strainer fishW3 Weight of fishGrading ToolsNine different grading tools were used for thisexperiment, namely:a.Plastic Basinb.Plywood Boxc.Meshed Boxd.Woven Baskete.Sorting tablef.Grading cageg.Dip neth.Hang Grading neti.Wooden panelThe fry was collected from the rearing trough, withthe aid of scoop net and put inside a strainer forestimation. After this they were then placed insideeach of the grading tools. The fry was only gradedonce using one type of grading tools to separate thesmaller ones from the bigger one and placed insidea separate rearing trough to monitor the mortality.Evaluation of Mortality RatesThe mortality rate was recorded by carefullyremoving and counting the dead fry, from each ofgrading tool throughthe rearing trough after eachgrading by usiing scoop net, they were latercounted. The percentage mortality was thencalculated according to FAO (2005) using theformula:111
Journal of Aquaculture Engineering and Fisheries ResearchGabriel et al., 2(3): 109-118 (2016)Journal abbreviation: J Aquacult Eng Fish ResNo of mortality100 Total no of fish graded 1Evaluation of Water Quality ParametersDuring the study, the following water qualityparameters were monitored: temperature, hydrogenion concentration (pH), dissolved oxygen (DO),ammonia nitrogen and nitrite nitrogen. Temperaturemeasurements were taken during the experimentalperiod using mercury in glass thermometer (0C).Hydrogen ion concentration (pH) was determinedby the use of a pH meter (Model HI 9812, Hannahproducts, Portugal). Dissolved oxygen levels in theexperimental tank were determined, twice at thebeginning and at the end of the experiment by theWinkler method (APHA, 1985). Ammonia nitrogenand nitrite nitrogen were measured using a test kitwith calorimetric chart produced by SUNPU,Biochem, Beijing, China.Data AnalysisThe data obtained from this study were collated andsubjected to ANOVA (Analysis of variance),difference among mean where existed were determined by Tuckeys multiple comparison test (Zar,1996).Results and DiscussionPhysical Observation of FishThe experimental fish used were very active andfree from disease or any external bruise, which arecapable of inducing stress or mortality.Water Quality ParametersThe results of physico chemical parameters, pHtemperature, dissolved- oxygen, nitrite nitrogen,(N-N02), ammonia- nitrogen (N-NH3), recorded inthe course of the trial were not significantlydifferent (p 0.05) in all the experimental weeks(Table 1).Number of Fries GradedThe results of fries graded were recorded for all theten grading tools, in all the experimental weeks. Inweek 2, the lowest value of graded fish (3.14 5.00)was observed in plywood box (PWB), while thehighest (720.67 26.63) was recorded in sortingtable (ST). In week 3, PWB, had the lowest value(390.00 2.00) and sorting table (ST) had the112highest. In week 4, 5, and 6 plywood box (PWB)consistently had the lowest value of graded fish,while sorting table (ST) had the highest value inthese weeks (Table 2).Mortality of Fish Fries Using Different SortingToolsThe mean values of % mortality recorded by usingdifferent tools were presented in table 4.3. Theresult indicated that the highest values of mortality(91.67 12.58, 3.12.67 3.51, 173.67 7.77, 41.00 4.00 and 31.33 1.53) were observed in week 2, 3,4, 5 and 6 respectively. While grading cage (GC),recorded the lowest values (4.67 1.53, 5, 33 1.53,1.00 0.00. 0.00 0.00, 0.00 0.00) in week 2, 3, 4,5, and 6 respectively (Table 3).Comparative Percentage Mortality at DifferentAge of Fish Using Different Sorting ToolsThe percentage mortality of fish recorded by usingdifferent sorting tools are shown in (Figure 1). Theresults indicated that in all the sorting tools thepercentage mortality tends to decrease as age of thefish increases. In Dip Net (DN) the highest value(3.26 0.11) was recorded at age 2, while thelowest value (0.46 0.11) at 6 weeks of age, forgrading cage (GC) the highest value (0.80 0.20)was recorded at age 2, while at age 5 and 6 nomortality was recorded. In hand grading net (HGNthe highest value of 1.4 0.20 was observed at age2, no mortality was recorded at 6 weeks. In usingmeshed box (MB), the highest mortality value of1.96 0.47 was recorded at age 2, while age 6 hasthe lowest value of 0.87 0.11. The highest valuesof 2.53 0.40 and 7.03 0.49, and the lowest values0.90 0.17 and 1.16 0.35 were recorded in PB andPWB respectively at week 2. The highest values of50.20 0.20, 1. 36 0.25 and 1.80 0.20, with thecorresponding lowest values of 2.13 0.11, 0.60 0.20 and 0.53 0.11 recorded respectively insorting tools (ST) Woven basket (WB), andWooden grading panel, (WGP), In rearing of fish.Malison (2000) reported that pH, temperature anddissolved oxygen are the three most importantwater quality variables in fish hatchery. Thedifferences in survival and mortality among thenine grading tools were not attributable to waterquality parameters because these variables weresimilar in all the grading groups and were within
Journal of Aquaculture Engineering and Fisheries ResearchGabriel et al., 2(3): 109-119 (2016)Journal abbreviation: J Aquacult Eng Fish Resthe acceptable limits for hatchery production(Ayinla and Nwadukwe, 1990; Haylor and Mollah,1995).It should be borne in mine that sorting fish according to size is a standard rearing procedure incommercial rearing system and on fish farms(Melntyre et al., 1987; Popper et al., 1992;Kamstra, 1993). Its aim is to simplify feeding (byapplying the appropriate feed granulation size andration) and to limit phenomena of domination andinter -individual interaction (Jobling 1995). Theassumption is that separating smaller fish willprotect them from domination by large fish, thusimproving their growth rate and increase stockbiomass (production). The results of this workindicated various degrees of effectiveness usingdifferent sorting tools as revealed in the diver’smortalities of fish recorded.It was deduced from the results obtained in thisstudy that the number of fish sorted, using differentsorting tools varied significantly (p 0.05) fromeach other, with sorting table having the highestnumber, supporting the findings of Togugeni et al.(1997) who obtained similar results in using threedifferent tools to sort tilapia (Oreochromis niloticus). This may be due to the fact that sorting tablehas a very flat and wide surface, which allows fryto be sorted easily. Also, the number of fry sortedusing different tools in this work seemed to beincreasing as the age of the fry increased. Thisdisagreed with the findings of Melard et al. (1996)who observed a contrary trend in the number oflarvae of perch (Perca fluviatilis) sorted after 44days. This may be due to the fact that the two fisheswere sorted at different ages after 44 days, the fishhave grown to some extent, and cannibalism of thesmaller ones by the bigger fish may have occurredthus reducing the number of the fish. According toGabriel et al. (2007b), the variability of individualgrowth patterns especially at the early stages whengrowth is allometric and potentially maximalcannot be over emphasized. Therefore, hugediscrepancies between individual growth patternsduring this period would favour the precociousemergence of cannibal fish resulting in their lowernumber.The mean mortality of baby fish observed in thiswork by using different sorting tools, vary significantly (P 0.05) from one sorting tool to another.Also, the mortality of the fish tends to decrease asthe age of the fish increased. This result is in linewith the findings of Koebele (1982) who observedsimilar results in red belly tilapia (Tilapia Zilli). Hepostulated that sorting of fish with different toolsmodify the various degrees of mortality recorded.Wickins (2005) and Kamstra (1993) found thatmortality of fish was mainly governed by physiological responses and not necessarily social interactions. While Purdom (2004) and Jobling (1982)found that mortality in larvae of sorted sole, Soleasolea and plaice, Pleuronectes platessa dependedon the efficiency of the sorting tools that were used.Conversely, Wickins (2005) observed an increasein larvae mortality as a result of defective gradingtool.Moreover, Dewandel (2002) found that the effectsof four different sorting tools on the survival andmortality of Atlantic cod (Gadus morhua) varyfrom one tool to another, as observed in this study.This according to them may be as a result of socialstress and increased motor activity, which ultimately leads to mortality. The various degree ofmortality observed in the various sorting tools maybe due to inter individual interactions as a result ofthe efficiency of the tools. Dill (1983) proposed thehypothesis that the highest level of inter individualinteractions occurs between sorted fishes’ relativeto their sorting tool. In effect, this means that thesurvival of fish is directly proportional to theefficiency of the grading tools used.However, the pooled data from the nine sortingtools indicated that the percentage mortality thoughvaried according to the age of the fish, also variedin different sorting tools. Similar results wereobtained with larvae of walleye (Coho salmon).This support the relevance of size-sorting larvaefish, especially within a standard intensive rearingframe work, implying sorting at regular intervals asthe age of the fish increases. This natural progressive sorting limits the cannibal emergence, althoughthe variability of individual growth patterns may besubstantial (Jensen 1988; Melard et al., 1995).113
Journal of Aquaculture Engineering and Fisheries ResearchGabriel et al., 2(3): 109-118 (2016)Journal abbreviation: J Aquacult Eng Fish ResTable 1.Physico-Chemical Parameters in Rearing Tanks During The Experiment (Mean SD)ParameterspHTemperature (0C)Dissolved oxygen (mg/l)N-N02 (mg/l)NH3 (mg/l)Table 2.Experimental Weeks236.57 0.006.50 0.1328.78 0.5429.14 0.866.70 0.306.68 0.460.0029 0.010.0028 0.010.32 0.040.36 0.0616.58 0.1229.24 0.646.74 0.320.0030 0.020.30 0.0346.56 0.1129.11 0.146.59 0.410.0027 0.020.38 0.0856.48 0.1329.18 0.766.41 0.880.0026 0.060.39 0.08Number of Graded Fish Fries Using Different Sorting Tools.ToolsAGEDN(WEEKS)2508.67 58.31a3477.00 1.00a4490.00 1.00a5492.00 1.00a6527.00 8.54aKey:GC577.67 22.01d604.00 6.93d652.33 14.50c797.00 12.12b857.33 24.50aHGN573.33 6.35d588.33 11.50d638 0.000c698.00 16.00b744.00 10.39aMB445.00 5.
seed for stocking the fish ponds and natural water bodies has indeed increased steadily (Dada, 2006). Artificial propagation methods constitute the major practicable means of providing enough quality seed for rearing in confined fish enclosure waters such a fish ponds, reservoirs and lakes (Conceicao et al., 2005; Akinrotimi et al., 2011c).
When I found One Fish Two Fish Red Fish Blue Fish I was sure I’d found the best learn-to-count book and that it would explain how to count without a grown-up to get you started.7 Here’s how it begins: One fish, two fish, red fish, blue fish. Black fish, blue fish old fish, new fish. This one has a litt
r. Seuss's One fish, two fish, red fish, blue fish is a clas-sic children's story, a simple rhyming book for beginning readers. We need a similar rhyme to help people grasp the problems afflicting Alberta's native fish species. It might read like this: Two fish, one fish, dead fish, no fish, No grayling or goldeye, something's amiss .
Fish noun Fish noun Examples Freshwater fish live in rivers and lakes. Freshwater fish live in rivers and lakes. Saltwater fish live in oceans and seas. Saltwater fish live in oceans and seas. The fish is swimming in the water. The fish is swimming in the water. The fish is looking at the bait. The fish is looking at the bait. freshwater fish .
Sorting: Overview One of the most commonly used and well-studied kernels. Sorting can be comparison-based or noncomparison-based. The fundamental operation of comparison-based sorting is compare-exchange. The lower bound on any comparison-based sort of n numbers is ( nlogn). We focus here
1. Explain in detail about sorting and different types of sorting techniques Sorting is a technique to rearrange the elements of a list in ascending or descending order, which can be numerical, lexicographical, or any user-defined order. Sorting is a process through whi
eating fish and chips on the beach, how many goldfish they have in their fish tank at home, fish have bones, fish only live in water, some fish can jump and fish are slimy. What a wealth of prior knowledge and understanding about fish these preschoolers already had.
Page 1 of 37 2012 HOME ECONOMICS SEC MARKING SCHEME PAPER I 1a. Two other types of fish (2 x 0.5 marks) oily fish, shell fish. b.i. Type of fish which has tough fibres (0.5 mark) oily fish b.ii. Type of fish which is easily digested (0.5 mark) white fish c. Nutritive value of fish
Fish Dichotomous Key Step 1 If fish shape is long and skinny then go to step 2 If fish shape is not long and skinny, then go to step 3 Step 5 If fish has spots, then go to step 6 If fish does not have spots, then go to step 7 Step 2 If fish has pointed fins, it is a trumpet fish If fish has smooth fins, it is a spotted moray eel Step 6
