Population growth, trophic level, and reproductive biology of two congeneric archer fishes (Toxotes chatareus, Hamilton 1822 and Toxotes jaculatrix, Pallas 1767) inhabiting Malaysian coastal waters

Population growth, trophic level, and reproductive biology of two congeneric archer fishes ( Toxotes chatareus , Hamilton 1822 and Toxotes jaculatrix , Pallas 1767) inhabiting Malaysian coastal waters 1 first-author †E-mail:skdas_maa@yahoo.commagfish05@yahoo.com †E-mail:skdas_maa@yahoo.commagfish05@yahoo.com skdas_maa@yahoo.com 2 3 3 4 3 corresp ‡Corresponding Author ‡Corresponding Author †E-mail:skdas_maa@yahoo.commagfish05@yahoo.com †E-mail:skdas_maa@yahoo.commagfish05@yahoo.com skdas_maa@yahoo.com Marine Science Programme, School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E., Malaysia Marine Science Programme, School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E., Malaysia Biology Programme, School of Biological Sciences, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E., Malaysia Biology Programme, School of Biological Sciences, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E., Malaysia Marine Ecosystem Research Centre, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E., Malaysia Marine Ecosystem Research Centre, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E., Malaysia Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor D.E., Malaysia Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor D.E., Malaysia Population growth, trophic level, and some aspects of reproductive biology of two congeneric archer fish species, Toxotes chatareus and Toxotes jaculatrix , collected from Johor coastal waters, Malaysia, were studied. Growth pattern by length-weight relationship ( W = aL b ) for the sexes differed, and exhibited positive allometric growth (male, female and combined sexes of T . chatareus ; female and combined sexes of T . jaculatrix ) and isometric growth (male samples of T . jaculatrix only). Trophic levels of both species were analyzed based on 128 specimens. The results show that, in both species, crustaceans and insects were the most abundant prey items, and among crustaceans the red clawed crab Sesarma bidens and Formicidae family insects were the most represented taxa. The estimated mean trophic levels for T . chatareus and T . jaculatrix were 3.422±0.009 and 3.420±0.020, respectively, indicating that they are largely carnivores. Fecundity of T . chatareus ranged from 38 354 to 147 185 eggs for females with total length ranging from 14.5 to 22.5 cm and total body weight from 48.7 to 270.2 g, and T . jaculatrix 25 251 to 150 456 eggs for females with total length ranging from 12.2 to 23.0 cm and total body weight from 25.7 to 275.0 g. Differences in values of gonadosomatic and hepatosomatic indexes calculated for both species in this study may have resulted from uneven sample size ranges. Archer fish Toxotidae Mangrove Estuary Predator Growth Reproduction INTRODUCTION 1 Seven species in the genus Toxotes are commonly referred to as archer fishes (Allen, 2004 2004 ). They live mainly in the brackish water of mangrove-lined estuaries (Allen, 1978 1978 ; 2001 2001 ). These fishes are relatively scarce, swim fast, and have sharp eye vision (Blaber, 2000 2000 ), which makes collecting specimens with nets in the complex root network of mangrove forests challenging. Therefore, it is not surprising that little is known about the biology and ecology of these fascinating fishes. Recently, we have reported the length-weight and length-length relationships of archer fishes (combined sex) (Simon and Mazlan, 2008 2008 ). However, length-weight relationship (LWR) of archer fishes within and between sexes is still lacking. The relationship between length and weight of fish species is important and it is extensively used for: (1) estimation of weight from length due to technical difficulties and the amount of time required to record weight in the field (Kolher et al., 1995 1995 ); (2) conversion of growth in length equations to growth in weight for use in stock assessment models (Stergiou and Moutopoulos, 2001 2001 ; Özaydin and Taskavak, 2007 2007 ); (3) estimation of the biomass from length observations (Anderson and Gutreuter, 1983 1983 ; Petrakis and Stergiou, 1995 1995 ); and (4) estimation of condition factors of the aquatic species (Petrakis and Stergiou, 1995 1995 ). The quality and quantity of food are among the most important exogenous factors directly affecting growth and, indirectly, maturation and mortality in fish, thus being ultimately related to fitness (Wootton, 1990 1990 ). Traditionally, information on the quality and quantity of food consumed by fish can be derived from feeding studies (Jennings et al., 2001 2001 ). Diet composition data are also used for the estimation of trophic levels (Pauly and Christensen, 2000 2000 ; Pauly and Sa-a, 2000 2000 ), which is very important for the management of aquatic resources. Despite the key role of trophic levels for fisheries and ecosystem research, up to now the position (trophic level) of archer fish in the food web has never been studied in Malaysia or elsewhere. Apart from length-weight relationship and trophic level, assessments of fecundity, gonadosomatic index and hepatosomatic index are fundamental indexes in the study of the biology and population dynamics of fish (Hunter et al., 1992 1992 ). Published information on archer fish reproductive biology is scarce. There exist only the reports on the fecundity and egg size of T . chatareus (Pethiyagoda, 1991 1991 ). Therefore, the aims of this study were to measure some important biological features, e.g., population growth pattern, trophic level, gonadosomatic index, hepatosomatic index, and fecundity, of T . chatareus and T . jaculatrix , two congeneric archer fishes collected from Malaysia’s Johor coastal waters. MATERIALS AND METHODS 1 Field sampling and laboratory preparation 2 Sampling was carried out in the coastal waters of Johor (01°24′53″ N; 104°09′44″ E), the southern part of Peninsular Malaysia, from August 2007 to November 2008. A total of 350 fish ( T . chatareus , n =145, 35 females and 110 males; T . jaculatrix , n =205, 63 females and 142 males) were collected using three-layered trammel net, cast net, scoop net, and trap. The gear was set up randomly throughout the study areas. The mesh sizes (stretched length) of the trammel and cast nets were 4.2, 6.5, 7.5, and 2.0 cm. Mesh size of the scoop net was 1.5 cm. The length of the net was 20 m for trammel net, 250 cm for the cast net, and 40 cm for the scoop net. The size of the trap was 80 cm×80 cm×90 cm (length×width×depth). The mesh size of the net used in the trap was 1 cm 2 . Specimen identification was carried out in the field according to the description given by Allen ( 2001 2001 ; 2004 2004 ). Several individuals of varying sizes were saved for diet studies. In order to prevent further digestion and decomposition of the content, the preservative (4% (w/v) formaldehyde) was injected into fish’s body cavity soon after weight measurement. Length-weight relationship 2 Population growth of the two species of archer fish was estimated based on the length-weight relationship analysis. In the laboratory, specimens were sorted by sex, measured to the nearest 1 cm (total length), and weighed to the nearest 0.1 g (weight). Total length of individual fish was taken from the tip of the upper jaw to the tip of the caudal fin. The relationship between the length and weight of a fish is usually expressed by the equation W = aL b (Ricker, 1973 1973 ), where W is body weight (g), L is total length (cm), a is the intercept, and b is the slope (fish growth rate) (Beverton and Holt, 1996 1996 ). Determination of a and b values was done using a non-linear regression for which curve fitting was carried out by a non-linear iterative method using Levenberg-Marquardt and Simplex algorithms for obtaining best convergence χ 2 goodness of fit values using a computer programme, Microcal Origin™ Version 6.0 (Simon and Mazlan, 2008 2008 ). The degree of adjustment of the model studied was assessed by the correlation coefficient ( r 2 ). A t -test was performed to test whether the computed value of b was significantly different from 3.0, indicating the type of growth: isometric ( b =3.0), positive allometric ( b> 3.0), or negative allometric ( b< 3.0) (Spiegel, 1991 1991 ). In all cases a statistic significance of 5% was adopted. Stomach content and trophic level analysis 2 In the laboratory, the digestive tract was removed and fixed in 70% (v/v) ethanol to provide further and longer preservation in the museum. Diet estimation was achieved by analyses of stomach contents from pre-selected samples (63 T . chatareus and 65 T . jaculatrix ). Stomach fullness was determined according to Joyce et al.( 2002 2002 ). Stomach contents were analyzed under the microscope and quantified in accordance with occurrence method (Hyslop, 1980 1980 ; Gunn and Milward, 1985 1985 ). Frequency of occurrence ( f o ) and percentage weight (wt%) were examined for different length classes. Finally, diet composition data were also used for the estimation of the trophic levels of T . chatareus and T . jaculatrix . Trophic level ( TROPH ) expresses the position of organisms within the food webs that largely define aquatic ecosystems (Pauly and Christensen, 1995 1995 ; 2000 2000 ; Pauly et al., 1995 1995 ; 1998 1998 ; Pauly and Palomares, 2000 2000 ). TROPH value was calculated from the dataset using TrophLab (Pauly et al., 2000 2000 ), which is a stand-alone application for estimating TROPH and its standard error ( SE ) using the weight or volume contribution and the trophic level of each prey species to the diet (Pauly et al., 2001 2001 ). Real consumers do not usually have TROPHs with integer values and the definition of TROPH for any consumer species i is: $$TROPH_i = 1 + \sum\limits_{j = 1}^G {DC_{ij} } \times TROPH_j$$ , where TROPH j is the fractional trophic level of prey j , DC ij represents the fraction of j in the diet of i , and G is the total number of prey species. Thus defined, the trophic level of aquatic consumers is a measurable entity that can take any value between 2.0 for herbivorous/detrivorous and 5.0 for piscivorous/carnivorous organisms (Pauly et al., 1998 1998 ; Pauly and Palomares, 2000 2000 ). Reproductive biology 2 Each fish was dissected, and the gonad and liver were removed and weighed (wet weight) to the nearest gram. Fecundity, considered as the total number of oocytes present in mature gonad (ripe), was estimated from 49 females (12 T . chatareus and 37 T . jaculatrix ). Briefly, after fixing in formalin, the gonads were carefully dissected and weighed to the nearest 0.1 g. Sub-samples were taken from three different locations of each ovary: near the base, mid part, and apical part, and were weighed to the nearest 0.01 g. Oocytes were loosened from the trabeculae and counted, and the total number of oocytes in the ovary was calculated and is reported here as fecundity (Clavier, 1992 1992 ). The gonadosomatic index ( GSI ) was calculated as GSI =( GW / BW )×100%, where GW is gonad wet weight (g), and BW is body wet weight (g) (excluding gonad weight). The hepatosomatic index ( HSI ) was calculated as HSI =( LW / BW )×100%, where LW is liver wet weight (g) (Mazlan and Rohaya, 2008 2008 ). RESULTS 1 Length-weight relationship 2 Length-weight relationship was derived from 145 T . chatareus and 205 T . jaculatrix samples. The T . chatareus samples ranged from 9.8 to 22.5 cm in total length and 17.2 to 270.2 g in total body weight for females, and 8.5 to 20.0 cm in total length and 12.0 to 180.2 g in total body weight for males; and the T . jaculatrix samples ranged from 8.7 to 23.0 cm in total length and 13.4 to 275.0 g in total body weight for females, and 8.5 to 19.0 cm in total length and 12.0 to 142.8 g in total body weight for males. The intercept a for combined sexes of T . chatareus and T . jaculatrix was 0.007 and 0.012, and correlation coefficient r 2 was 0.971 and 0.959 (Fig. 1 1 ). Intercept a for male T . chatareus was 0.01 and for female was 0.005 and correlation coefficient r 2 for male was 0.969 and for female was 0.970, while in T . jaculatrix intercept a was 0.015 for male and 0.007 for female and coefficient correlation r 2 was 0.958 for male and 0.950 for female (Fig. 2 2 ). The values of the slope or exponent b for males (3.246), females (3.465), and combined sexes (3.353) were significantly ( P < 0.05) higher than 3, exhibiting a positive allometric growth for T . chatareus , whereas the exponent b value for male (3.076) was close to 3.0 ( P > 0.05), showing isometric growth pattern (i.e., changing the body form following the cube law (volume= L 3 )) for T . jaculatrix . In contrast, the estimated b values for female (3.310) and combined sexes (3.160) were significantly ( P < 0.05) higher than 3 and therefore exhibited a positive allometric growth for T . jaculatrix , indicating that weight increases faster than length (Figs. 1 1 and 2b 2b ). Solid regression line represents non-linear fit of T . chatareus and dashed regression line represents non-linear fit of T . jaculatrix Solid regression line represents non-linear fit of male specimens in both species and dashed regression line represents non-linear fit of female specimens Stomach content and trophic level 2 The stomachs of 63 T . chatareus samples were examined, and 8% were found empty and 92% contained food items, whereas in 65 T . jaculatrix stomachs 11% were empty and 89% contained food items. A total of 2 crustaceans (crab and shrimp), 4 different insect families, and 1 teleost species were identified (Table 1 1 and Fig. 3 3 ). After grouping all food items into three categories, crustaceans in particular with the red clawed crab ( Sesarma bidens ) (70%, 67%) were the main prey items observed in both T . chatareus and T . jaculatrix , followed by insects (namely Formicidae 12%, 13%; Dytiscidae 5%, 6%; Araneidae 3%, 5%; and Cerambycidae 3%, 3%). Penaeus sp. occurred in 3% and 2% in T . chatareus and T . jaculatrix stomachs, respectively. Teleost ( Toxotes sp.) constituted a tiny proportion of diet (5%) in T . jaculatrix while it was not found in T . chatareus stomachs (Table 1 1 and Fig. 4 4 ). Crustaceans formed the majority of the diet, 73% ( f o =92) and 69% ( f o =89) by weight, followed by insects 23% ( f o =87) and 26% ( f o =69) in T . chatareus and T . jaculatrix , respectively (Table 1 1 ). N : number of organisms; W : total weight; wt%: percentage weight in g; n : number of stomachs with prey item; f o : frequency of occurrence; w : weight per stomach sampled in g Species Prey category N W (g) wt% n f o w (g) T. chatareus Crustaceans 175 46 73 58 92 0.73  Crab ( S . bidens ) 151 44 70 48 76 0.69  Shrimp ( Penaeus sp.) 24 2 3 10 16 0.03 Insects 328 14 23 55 87 0.22  Formicidae 153 7 12 29 46 0.11  Dytiscidae 73 3 5 16 25 0.05  Araneidae 57 2 3 6 10 0.03  Cerambycidae 45 2 3 4 6 0.03 Teleosts 0 0 0 0 0 0.00 Total 503 60 96 0.95 8 T. jaculatrix Crustaceans 184 27 69 58 89 0.42  Crab ( S . bidens ) 156 26 67 50 77 0.40  Shrimp ( Penaeus sp.) 28 1 2 8 12 0.02 Insects 205 10 26 45 69 0.15  Formicidae 97 5 13 25 38 0.08  Dytiscidae 51 2 6 10 15 0.03  Araneidae 43 2 5 6 9 0.03  Cerambycidae 14 1 3 3 5 0.02 Teleosts 2 2 5 2 3 0.03   Toxotes sp. 2 2 5 1 2 0.03 Total 391 39 100 0.60 (a) Crab. Plus sign indicates chelate leg and asterisk indicates non-chelate leg; (b) Shrimp; (c) Insect; (d) Teleosts n : number of fish in each length class (excluding empty stomach) The estimated trophic levels ranged from 3.230 to 3.590 with mean value of (3.422±0.009) for T . chatareus and from 3.24 to 4.39 and mean value of (3.420±0.020) for T . jaculatrix (Fig. 5 5 ). Trophic levels in both species gradually increased with size (Fig. 5 5 ). Open circles represent mean TROPH values/trophic level and solid bars represent variants of prey items Reproductive biology 2 Estimated fecundity ranged from 38 354 to 147 185 eggs for T . chatareus females and 25 251 to 150 456 eggs for T . jaculatrix females. The sample size, minimum and maximum numbers of eggs, and mean egg count values are presented in Table 2 2 . The fecundity of mature females increased with total length (TL), total body weight (BW), eviscerated weight (EW) (excluding the stomach and gonad weights) and ovary weight (OW) (Fig. 6 6 ). The calculated mean gonadosomatic index was (1.061±0.075) for T . chatareus and (1.796±0.077) for T . jaculatrix , and hepatosomatic index was (1.201±0.080) for T . chatareus and (1.332±0.070) for T . jaculatrix (Table 2 2 ). 2 Species 2 Samples (female) 3 Fecundity 2 Samples (combined sex) 3 Gonadosomatic index 3 Hepatosomatic index Mean SE Range Mean SE Range Mean SE Range T. chatareus 12 60 716 ±8 303.389 38 354~147 185 145 1.061 ±0.075 0.02~7.26 1.201 ±0.080 0.130~4.430 T. jaculatrix 37 55 063 ±3 552.849 25 251~150 456 205 1.796 ±0.077 0.03~8.70 1.332 ±0.070 0.130~4.680 Dot bar represents non-linear fit of T . jaculatrix and solid bar represents non-linear fit of T . chatareus in (a), while dot bar represents linear fit of T . jaculatrix and solid bar represents liner fit of T . chatareus in (b)~(d) DISCUSSION 1 In the current study, we observed that T . chatareus and T . jaculatrix (except male samples of T . jaculatrix ) exhibit similar growth patterns (i.e., positive allometry and fish becomes more rotund as length increases), in accordance with a previous study (Simon and Mazlan, 2008 2008 ). The slopes or exponents ( b ) for male, female, and both sexes for T . chatareus were significantly ( P < 0.05) higher than 3.0, reflecting a positive allometric growth, whereas in T . jaculatrix the values of exponent b for males were close to 3.0 ( P > 0.05), showing isometric growth pattern. The estimates of the parameter b , varying between 2 and 4 (Bagenal and Tesch, 1978 1978 ), remain within the expected range (3.076~3.465), with a mean b value of 3.268 (±0568) for all the species. A high degree of positive correlation between total length and total weight of both species is indicated by high values of correlation coefficient r 2 . The length-weight relationships of T . chatareus and T . jaculatrix within and between sexes have not been previously recorded in Malaysia or elsewhere. However, as a result of the size-selective characteristics of fishing gears, the samples may not have included all available lengths. For more precise weight estimations, the application of these length-weight relationships should be limited to the observed length ranges; otherwise it may be erroneous (Petrakis and Stergiou, 1995 1995 ; Froese, 1998 1998 ). Even though the change of b value depends primarily on the shape and fatness (size) of the species, various factors may be responsible for the differences in parameters of the length-weight relationships among seasons and years, including temperature, salinity, food (quantity, quality, and size), sex, time of year, and stage of maturity (Pauly, 1984 1984 ; Sparre, 1992 1992 ). The parameter b , unlike the parameter a , may vary seasonally, even daily, and between habitats (Bagenal and Tesch, 1978 1978 ; Gonçalves et al., 1997 1997 ; Taskavak and Bilecenoglu, 2001 2001 ; Özaydin and Taskavak, 2007 2007 ). Thus, the length-weight relationship in fish is affected by a number of factors including gonad maturity, sex, diet, stomach fullness, health, and preservation techniques as well as season and habitat; however, none of them were taken into consideration in the present study. Our results show that the two species of archer fishes in the Johor coastal waters feed primarily on crustaceans (mostly Sesarma bidens ) and insects (in decreasing order of abundance: Formicidae, Dytiscidae, Araneidae, and Cerambycidae), followed by teleost. Crustaceans (i.e., crabs and shrimps) dominated the stomach content by weight, while insects dominated the diet by number in all length classes of T . chatareus and T . jaculatrix (Table 1 1 and Fig. 4 4 ). It is assumed that insects were captured by the two species through shooting from the overhanging mangrove vegetation in the study area. This feeding mechanism has been well documented (Timmermans, 2000 2000 ; 2001 2001 ; Timmermans and Vossen, 2000 2000 ; Rossel et al., 2002 2002 ; Schuster et al., 2004 2004 ; 2006 2006 ). Smaller individuals with total length of 8.5~11.5 cm of both species fed on a smaller number of prey items compared to larger length classes. The diet differences among the size classes are probably due to the energy requirements, which vary according to the developmental stage. Indeed, during ontogeny, fishes often change their diet mediated by allometric, morphological changes (Karpouzi and Stergiou, 2003 2003 ), thus being able to exploit sequentially a series of prey sizes ranging from phytoplankton and small size zooplankton to much larger prey (Wootton, 1998 1998 ). Our results show that the diets of T . chatareus and T . jaculatrix include crabs, shrimps, and insects prey, which is consistent with Blaber ( 2000 2000 )’s results. However, Blaber found that the two fish species also take plant material, which he explained as an occasional behavior. In addition, the similar ontogenetic changes in the diet in T . chatareus were reported in the present study and by Blaber ( 2000 2000 ) (Figs. 4 4 and 5 5 ). The methods of stomach fullness assessment in the present study allowed observing the prey items in the stomach by dissection. A similar method of assessment has been also reported by Joyce et al.( 2002 2002 ). Larger archer fishes appear to develop a higher degree of carnivory by capturing large crabs, shrimps, insects or even to display cannibalistic behavior on juvenile fish. The estimated trophic levels for T . chatareus and T . jaculatrix are similar to those calculated by Stergiou and Karpouzi ( 2001 2001 ) for other pelagic species such as Gadiculus argenteus argenteus , Trachurus mediterraneus , and Trachurus trachurus . All these species exhibit similar feeding preference, namely, crustaceans, fish larvae, and mysids, and can be considered as largely carnivores. Our results indicate that the two species of archer fishes are largely opportunistic predators feeding on a wide spectrum of prey species such as crustaceans, insects, and, rarely, teleost, depending on the food availability in the environment. The fecundity estimates of T . chatareus and T . jaculatrix show that these species have a reproductive strategy common to other fish families (e.g., Carangidae and Scombridae) with lack of parental care: i.e., they produce a high number of smaller size pelagic eggs. These results agree with the findings for T . chatareus females in previous studies (Allen et al., 2002 2002 ; Pethiyagoda, 1991 1991 ). The increase in fecundity with body length and weight is consistent with the observations made in other fish species (Gartner, 1993 1993 ; Barbin and McCleave, 1997 1997 ). An increase in gonadosomatic index value is an indication of increased reproductive activity. In contrast, hepatosomatic index is a good indicator of recent feeding activity (Tyler and Dunn, 1976 1976 ) and hepatosomatic index value decreases during spawning, suggesting that the fishes may decrease its feeding activity during reproduction. In the present study, due to scarcity of samples in each month’s sampling programme, we were unable to obtain the monthly gonadosomatic and hepatosomatic indexes of both species. However, differences in values of gonadosomatic index and hepatosomatic index calculated for both species in this study may have resulted from uneven sample size ranges. Moreover, there was no previous study on these reproductive indexes in archer fish to confidently infer real gonadosomatic index and hepatosomatic index values from gonad and liver analyses. CONCLUSION 1 In conclusion, we observed that T . chatareus (male, female, and combined sexes) exhibited positive allometric growth pattern (species become more rotund as their length increases) and T . jaculatrix exhibited both positive allometric (female and combined sexes) and isometric growth (male samples only) patterns (changing the body form following the cube law (volume= L 3 )) by the exponent b values derived from the allometric length-weight relationship. The estimated trophic levels indicate that T . chatareus and T . jaculatrix are opportunistic fish feeders that take a wide spectrum of prey species such as crustaceans, insects, and, rarely, teleost, depending on the food availability in the environment. The estimated fecundity demonstrates that both species are highly fecund and their fecundity increases linearly with body length, body weight, ovary weight, and eviscerated weight. Low gonadosomatic index and hepatosomatic index values obtained from both samples might be as a result of abundant juvenile samples; therefore, further studies are needed to obtain more information about the reproductive biology of this fascinating fish. Our findings will be useful for ecological modeling for a better representation of the trophic flows associated with large, medium, and small pelagic fishes in Malaysian estuaries. References GR Allen . A review of the archer fishes (family Toxotidae) . Records of the Western Australian Museum , 1978 . 6 ( 4 ): 355 - 378 . . A review of the archer fishes (family Toxotidae) GR Allen . KE Carpenter , VH Niem . Toxotidae-Archer Fishes . FAO Species Identification Guide for Fishery Purposes. The Living Marine Resources of the Western Central Pacific , 2001 . Volume 5 : Rome, Italy FAO , 3212 - 3215 . Bony Fishes part 3 (Menidae to Pomacentridae) . Toxotidae-Archer Fishes GR Allen . 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Ecology of Teleost Fishes , 1998 . : Dordrecht, the Netherlands Kluwer Academic Publishers , 425 Fish and Fisheries Series, No. 24 . Ecology of Teleost Fishes Heartiest thanks to the respected laboratory and field technicians for their efforts and support throughout the study. Special thanks to our colleague Mark Alabi at the Universiti Kebangsaan Malaysia for critical reading of the manuscript. All field sampling and laboratory protocols followed and complied with in the current laws of Malaysia. 10.1631/jzus.B0920173 Project supported by the Malaysia government through UKM-Science Fund (No. 04-01-02-SF0124) and the fellowship of Skim Universiti Kebangsaan Malaysia (No. UKM-OUP-FST-2008) 2009-06-22 2009-10-28 2009-09-27 2022-01-05 Copyright © 2009, Journal of Zhejiang University Science 2009 Journal of Zhejiang University-SCIENCE B (Biomedicine and Biotechnology) 12 10