Relative Condition Factor and Parasitism in Anostomid ﬁshes from the ﬂoodplain of the Upper Paraná River, Brazil

Veterinary Parasitology 177 (2011) 145–151 View metadata, citation and similar papers at core.ac.uk brought to you by CORE Contents lists available at ScienceDirect provided by Elsevier - Publisher Connector Veterinary Parasitology journal homepage: www.elsevier.com/locate/vetpar Relative condition factor and parasitism in anostomid fishes from the floodplain of the Upper Paraná River, Brazil Gislaine Guidelli a,∗, Washington Luiz Gomes Tavechio a, Ricardo Massato Takemoto b, Gilberto Cezar Pavanelli b a Universidade Federal do Recôncavo da Bahia (UFRB), Centro de Ciências Agrárias, Ambientais e Biológicas (CCAAB), Núcleo de Estudos em Pesca e Aquicultura (NEPA), Brazil b Universidade Estadual de Maringá (UEM), Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (Nupélia), Brazil article info abstract Article history: Individuals of four species of Leporinus were captured in the floodplain of the Upper Paraná Received 26 July 2010 River and their metazoan parasites were collected. Fifty-eight taxa of ectoparasites and Received in revised form endoparasites were recorded: 31 in Leporinus lacustris,32inLeporinus friderici,28inLep- 19 November 2010 orinus obtusidens and 25 in Leporinus elongatus. The aim of this paper was to study the Accepted 23 November 2010 relationship between the host’s condition and the parameters of infrapopulations and infracommunities. The health of the host was represented by the relative condition factor (Kn). Keywords: Richness and number of individuals in the infracommunities of ectoparasites covariated Relative condition factor Ectoparasites with the Kn of the hosts in one species of fish. Some infrapopulations of ectoparasites Endoparasites covariated negatively and/or the mean Kn of parasitized individuals was lower than those Leporinus without parasites. The abundance in some infrapopulations of endoparasites covariated Floodplain positively with the Kn and/or the mean Kn of parasitized fish was better. These results may Paraná river be related to different transmission strategies used by ecto and endoparasites. © 2010 Elsevier B.V. Open access under the Elsevier OA license. 1. Introduction The condition factor, both relative or alometric, and the presence or abundance of certain species of parasites are The condition factor represents a quantitative indicator related variables (Ranzani-Paiva et al., 2000; Tavares-Dias of the well-being of fish (Vazzoler and de, 1996). Analysis et al., 2000; Lizama, 2003; Isaac et al., 2004). But often, of variations in this indicator between populations or indi- fish are naturally infected by many coexisting species that viduals can be used to demonstrate the effects of different demonstrate inter-relationships, i.e. each host individual factors, such as environmental quality and food resources harbors an infracommunity of parasites (sensu Bush et al., (Bolger and Connolly, 1989). Because it is a measure regard- 1997). Thus, it is also important to consider the effect of ing health, it can also be effective to indicate the effects these sets of species on the condition of the hosts. Accord- of parasites on their hosts, both in natural and confined ing to Brasil-Sato (1999), knowledge of the influence of this environments. mixed type of parasitism can be a useful tool in ichthyopar- asitology, in particular applied to fish farming. The studied species of the genus Leporinus harbor numerous species of parasites (Guidelli, 2006; Guidelli et al., 2006) and have potential or are already important for ∗ Corresponding author at: Universidade Federal do Recôncavo da aquaculture (Froese and Pauly, 2009). Knowledge of the Bahia, Centro de Ciências Agrárias, Ambientais e Biológicas, Rua Rui Bar- amplitude of fauna that these fish are capable of harboring, bosa, Campus Universitário, 44380-000 Cruz das Almas, Bahia, Brazil. Tel.: +55 75 3621 1558; fax: +55 75 3621 1558. as well as the indication of the possible effects that parasite E-mail address: [email protected] (G. Guidelli). species or communities may have on them are useful infor- 0304-4017 © 2010 Elsevier B.V. Open access under the Elsevier OA license. doi:10.1016/j.vetpar.2010.11.035 146 G. Guidelli et al. / Veterinary Parasitology 177 (2011) 145–151 mation for handling these animals in captivity, especially of each parasite species. Analyses in the infrapopulations in regard to ectoparasites, monoxenic life cycles and infest- were applied to species with prevalence higher than 10%, ing forms that can be easily transported in water from one as suggested by Bush et al. (1990). The Mann–Whitney’s habitat to another. U-test with correction for ties – Z(U) – was used to This study aimed to evaluate how the infracommuni- test differences between the mean Kn of males and ties and infrapopulations of parasites of four species of females and parasitized and non-parasitized fish for each Anostomid fishes from the floodplain of the Upper Paraná species (Zar, 1996). The level of significance adopted was River are related to the condition of these hosts, repre- p < 0.05. sented by the relative condition factor (Kn). We chose to use the relative condition factor as an indicator of the health status of animals because this index is not affected by 3. Results reproductive events or the formation of gonads (Le Cren, 1951). Fifty-eight taxa of metazoan ecto and endoparasites were identified. Leporinus lacustris harbored 31 species, 2. Materials and methods Leporinus friderici 32, Leporinus obtusidens 28 and Leporinus elongatus 25 species. Taxa recorded in the four host species, Samplings of hosts were carried out between May 2001 sites of infection/infestation and parasitism indicators are and June 2004 in lentic, lotic and semilotic environments of presented in Table 1. the floodplain of the Upper Paraná River (22◦50–22◦70S The mean values of the host’s Kn for total sam- and 53◦15–53◦40W). Information about the study area ple are presented in Table 2, where the means for can be found in Thomaz et al. (2004). Fish were cap- males and females are also shown. The Kn did not dif- tured, labeled, placed in plastic bags and transported on fer significantly between males and females (L. lacustris: ice to the laboratory of the Advanced Research Base of the Z(U) = 1.776, p = 0.075–L. friderici: Z(U) = 1.849, p = 0.064–L. Research Nucleus in Limnology, Ichthyology and Aquacul- obtusidens: Z(U) = 0.693, p = 0.486–L. elongatus: Z(U)= ture (Nupélia), where they were identified for later record 0.477, p = 0.632). It also did not differ between hosts col- of biometric and sex data. lected in three types of environments (L. lacustris: H = 0.359, The necropsy of the hosts, collection, preservation p = 0.825–L. friderici: H = 1.410, p = 0.493–L. obtusidens: and preparation of ecto and endoparasites were con- H = 1.162, p = 0.559–L. elongatus : H = 0.812, p = 0.661). Thus, ducted based on methodology suggested by Eiras et al. all fish of each species were treated as one data set. (2000). The terms infracommunity and infrapopulation, Among the analyzed specimens of L. lacustris, 4 and as well as the infrapopulation descriptors (prevalence, 45 were unparasitized by ecto and endoparasites, respec- intensity and abundance) were used according to Bush tively. For L. friderici these numbers were 4 and 27, et al. (1997). All parasites were collected, counted and for L. obtusidens 4 and 17, and for L. elongatus 2 and recorded separately for each individual host. Richness in 9, respectively. The mean Kn ± standard deviation of infracommunities refers to the total number of parasite parasitized and unparasitized fish, respectively, were: species in each fish. The identification of parasite taxa L. lacustris, ectoparasites = 1.026 ± 0.181, 0.844 ± 0.500; was performed using specialized literature and consulting endoparasites = 1.040 ± 0.200, 0.978 ± 0.172; L. friderici, paratypes. ectoparasites = 1.005 ± 0.114, 1.043 ± 0.125; endopar- Values of the relative condition factor were obtained for asites = 1.006 ± 0.119, 1.008 ± 0.100; L. obtusidens, all individual as described by Le Cren (1951). With the loga- ectoparasites = 0.999 ± 0.107, 1.087 ± 0.062; endopar- rithms of the values of standard length (Ls) and total weight asites = 1.003 ± 0.113, 1.010 ± 0.094; L. elongatus, (Wt) of each individual host, the curve was adjusted for ectoparasites = 1.025 ± 0.282, 1.048 ± 0.196; endopar- Wt/Ls (Wt = a·Ltb) and the values of the regression coef- asites = 1.002 ± 0.237, 1.105 ± 0.388. ficients a and b were estimated. The values of a and b were used for estimating values theoretically predicted of body weight (We) by using the equation: We = a·Ltb. Then 3.1. Infracommunities the relative condition factor (Kn) was calculated, which corresponds to the ratio between the observed weight Mean richness in the infracommunities of ectoparasites and the theoretically expected weight for a given length of L. lacustris was 3.42 ± 1.84 (1–10) and of endoparasites (Kn = Wt/We). was 1.38 ± 1.23 (1–4), for L. friderici these values were The non-parametric test Kruskal–Wallis (H) was used to 3.12 ± 1.66 (1–7) and 1.52 ± 1.36 (1–6), for L. obtusidens test differences of the mean Kn between the environments 4.02 ± 2.48 (1–10) and 1.15 ± 0.98 (1–3) and L. elongatus in the floodplain of the Upper Paraná River, considering 2.87 ± 1.94 (1–9) and 1.56 ± 1.26 (1–4), respectively for that different biotopes can influence the Kn. To assess ecto and endoparasites. the relationship between infracommunities and infrapop- Correlating the Kn of the hosts with species richness and ulations of parasites with the relative condition factor, total number of individuals of ectoparasites, only L. lacustris the nonparametric Spearman’s rank correlation coefficient presented significant results.

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