Effects of size difference and stocking density on cannibalism rate of juvenile grouper Epinephelus coioides

Hseu, Jinn–Rong

doi:10.1046/j.1444-2906.2002.00578.x

Cited by 32 publications

(33 citation statements)

References 12 publications

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“…Due to species-dependent morphological differences, the variability of dimensions during ontogeny and behaviour typical of a given species, diverse mathematical models are applied. The most commonly used models include those based on direct measurements of total length (TL) of cannibals and their prey or models based on such parameters as mouth width (MW), mouth gape (MG), body depth (BD) of a prey, head depth (HD) of a prey and head width (HW) of a prey (Folkvord and Otterå 1993;Baras and Dalmeida 2001;Hseu 2002;Kailasam et al 2002;Kestemont et al 2003;Hseu et al 2003b;Fessehaye et al 2005;Wallat et al 2005;Hseu et al 2007;Policar et al 2013;Baras et al 2014;Hseu and Huang 2014;Ribeiro and Qin 2015).…”

Section: Size-sortingmentioning

confidence: 99%

Intracohort cannibalism and methods for its mitigation in cultured freshwater fish

Naumowicz

Pajdak

Terech-Majewska

et al. 2017

Rev Fish Biol Fisheries

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Cannibalism is a common phenomenon that occurs in over 30 fish families. Most of the species are valuable objects of aquaculture and cannibalism is highly undesirable. Cannibalism is an aggressive behaviour, which can be caused by stress induced by various population and environmental factors and can occur in two main forms: early larval and late juvenile (or adult). Each of these forms can lead to severe losses of stock. Losses are caused not only by fish eating each other, but also by an increase in the number of infections (the result of body surface damage). It is important to understand the phenomenon of cannibalism in order to properly prevent, diagnose and reduce it. The main aim of this study was to present and examine some of the well-examined methods of cannibalism mitigation. Most of the methods consist of creating rearing conditions similar to natural conditions and to reduce stress. Moreover, because of large interspecies differences, similar methods can result in different effects depending on the species. Additional studies are needed to better understand the biology of each cultured species with particular emphasis on the impact of domestication, as well as to improve fish rearing conditions.

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Section: Size-sortingmentioning

confidence: 99%

Intracohort cannibalism and methods for its mitigation in cultured freshwater fish

Naumowicz

Pajdak

Terech-Majewska

et al. 2017

Rev Fish Biol Fisheries

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“…4 density (Hseu, 2002;Duray et al 1995;Tookwinas, 1989), whilst the percentage of abnormal larvae (curved and relatively smaller larvae) was significantly higher at incubation densities of 800 and 1,600 eggs/l than at 200 and 400 eggs/l. Hatching rates and percentage of normal larvae are higher at an aeration volume of 100 ml/min than at 500 and 1000 ml/min (Toledo, 2000).…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Skeletal anomalies in dusky grouper Epinephelus marginatus (Lowe 1834) juveniles reared with different methodologies and larval densities

et al. 2009

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A C C E P T E D M A N U S C R I P T Skeletal anomalies in reared dusky grouper juveniles ACCEPTED MANUSCRIPTThe first attempts to reproduce dusky grouper (Epinephelus marginatus, Lowe 1834) under controlled conditions started in 1995, but the egg and larvae quality was very low. Mass production is still encountering many difficulties, mainly concentrated in the larval period when very high mortality rates are observed, confirming what has been observed in the rearing of other grouper species. The main bottlenecks have been identified as the difficulty to properly nourish the larvae, stress shock syndrome, and the high deformation rates.We analysed 633 dusky grouper larvae and juveniles (0.2-7.2 cm total length, TL), sampled during two larval rearing cycles carried out in 2001 and 2002 in Italy. The specimens at different development stages were stained in toto for bone and cartilage and examined for skeletal anomalies during dusky grouper ontogenesis. The incidence of anomalies in groupers hatched from the same egg batch but reared using two different methods (green waters and semi-intensive rearing) and three stocking densities (8, 16 and 28 larvae/l) was compared, with a view to providing tools for identifying the most appropriate larval rearing method in order to at least limit the onset of skeletal anomalies.Our results suggest that during development no particular skeletal anomaly patterns (or fate) can be clearly identified as a high variability was observed in malformation typologies and the regions affected.No significant differences in the morphological quality between groupers reared using semi-intensive (LV02 lot) and green water (GW02-01 lot) methodologies were observed, whilst groupers reared at the highest stocking density (28 larvae/l) showed the highest frequency of deformed individuals (75.8%), the highest malformation charge (average of 5.5 anomalies per deformed individual), the largest range of anomaly typologies (38), and the highest incidence of individuals with at least one severe anomaly (30.9%). Whilst in green waters no evident effects of larvae density were observed on survival rates, the survival rate in large volume reared individuals (17.5%) was considerably higher with respect to those reared in green waters (0.2%) at 7-8 larvae/litre. This indicates that the semi-intensive methodology should be considered more effective in enhancing the survival rate of dusky grouper larvae.

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“…Previous studies have associated mortalities in larvae and juvenile stage to cannibalism and it is estimated to contribute up to 70-83% of the total mortality accumulated during the first 46-50 days of rearing C. gariepinus (14). Several studies have also shown that cannibalistic behaviour is intensified by increasing size heterogeneity at these stages; size variation is also a primary cause of agonistic behaviour, which in turn can have the same end effect as cannibalism (15). However with the result of homogeneity reported in the present study for growth, cannibalism is likely not the cause of mortality in the present study but may be linked to accessibility to food (14) had pointed out that high rate of mortality of African catfish is linked to inadequate larval food, improper feeding regime, stocking density and photoperiod (16) and (17) rightly stated that light and dark alternation generally are the main synchronizer of feeding activity, this is likely true for the developmental stage under study.…”

Section: Resultsmentioning

confidence: 99%

Effect Of Photoperiod On Hatching Success Of Eggs And Early Fry Performance Of Clarias Gariepinus (Siluriformes, Burchell 1822)

Ataguba¹,

Okomoda²,

Azave³

2015

TJS

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The present study investigated the effect of egg exposure to three light and dark regimes: 00D: 24L; 24D: 24L; and 12D: 12L on hatching and early growth of Clarias gariepinus larvae. Incubation was carried out in 30L black cylindrical plastic bowls. Hatching rates were determined 24hours post incubation while growth and survival were determined every three days for two weeks. Results obtained reveal no significant difference (P>0.05) in fertilization rate of eggs assigned to various photoperiods and no effect of photoperiod on mean final weight, mean weight gain, and specific growth rate of fry. However hatching rate and survival rate were significantly affected by light regime (P<0.05) with fry raised under the light regimes of 12L: 12D and 24L: 00D having significantly higher hatching (84%) and survival (54%) rates. A favorable temperature as well as better vision in search and capture of food aided fish under these treatments to perform better. Photoperiod can therefore be used to enhance incubation, hatching and early growth of C. gariepinus with potential to maximize hatching from egg batches.

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Effects of size difference and stocking density on cannibalism rate of juvenile grouper Epinephelus coioides

Cited by 32 publications

References 12 publications

Intracohort cannibalism and methods for its mitigation in cultured freshwater fish

Intracohort cannibalism and methods for its mitigation in cultured freshwater fish

Skeletal anomalies in dusky grouper Epinephelus marginatus (Lowe 1834) juveniles reared with different methodologies and larval densities

Effect Of Photoperiod On Hatching Success Of Eggs And Early Fry Performance Of Clarias Gariepinus (Siluriformes, Burchell 1822)

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