Host Total Length Research Articles

Ectoparasites of the Critically Endangered green sawfish Pristis zijsron and sympatric elasmobranchs in Western Australia

This study reports the metazoan ectoparasite fauna of juvenile Critically Endangered green sawfish, Pristis zijsron, and sympatric elasmobranchs in Western Australia. Five parasite taxa were found on 76 screened P. zijsron: Caligus furcisetifer (Copepoda: Caligidae), Dermopristis pterophila (Monogenea: Microbothriidae), Branchellion plicobranchus and Stibarobdella macrothela (Hirudinea: Piscicolidae), and praniza larvae of an unidentified gnathiid isopod. Only C. furcisetifer and D. pterophila were common, exhibiting discrepant site-specificity, with C. furcisetifer occurring mostly on the head and rostrum, and D. pterophila around the pectoral and pelvic fins. Intensity of infection for C. furcisetifer and D. pterophila increased with host total length and was influenced by host sex, but in opposite directions; intensity of C. furcisetifer was greater on female P. zijsron, whereas intensity of D. pterophila was greater on males. In the Ashburton River, likelihood of infection for C. furcisetifer and D. pterophila on P. zijsron increased with time since substantial freshwater discharge events, suggesting decreased salinity impacts both taxa. In addition to P. zijsron, five other sympatric elasmobranch species were opportunistically screened for ectoparasites in the study area: the giant shovelnose ray, Glaucostegus typus, the eyebrow wedgefish, Rhynchobatus palpebratus, the nervous shark, Carcharhinus cautus, the lemon shark, Negaprion acutidens, and the graceful shark, Carcharhinus amblyrhynchoides. Caligus furcisetifer was found on R. palpebratus; no other parasites of P. zijsron were found on other sympatric elasmobranch species. Conversely, Perissopus dentatus (Copepoda: Pandaridae) was found on all three carcharhinids but not on batoid rays (P. zijsron, G. typus or R. palpebratus).

Community ecology of the metazoan parasites of the Atlantic thread herring, Opisthonema oglinum (Lesueur, 1818) (Actinopterygii: Clupeidae) from the Sepetiba Bay, Rio de Janeiro, Brazil

This study aimed to evaluate the parasitic fauna of Opisthonema oglinum (Lesueur, 1818) from Southeastern Brazil. Between September 2017 and March 2018, a total of 100 specimens of O. oglinum from the Sepetiba Bay, Rio de Janeiro, Brazil (22°54'S, 43°34'W) were examined. Ninety one specimens of O. oglinum were parasitized by at least one species of metazoan with a mean of 5.84 ± 7.98 parasites/fish. Seven species were collected: 2 digeneans, 2 monogeneans, 2 copepods and 1 nematode. The digenean Parahemiurus merus (Linton) was the most abundant and dominant species, representing 43% of metazoan parasites collected. The parasite species richness was positively correlated with the total length of the hosts. Only Neobomolochus elongatus Cressey showed a positive correlation between host's total length and parasite prevalence. The mean parasite species diversity was not correlated with host's total length, but significant differences among the mean parasite diversity between males and females was observed. Opisthonema oglinum represents a new host record for Caligus mutabilis Wilson, Hysterothylacium sp. and Cribomazocraes travassosi Santos and Kohn. The copepod N. elongatus is recorded for the first time on the Brazilian coast.

Communities of Helminth Parasites in Sciaenid Fish From the Alvarado Coast, Veracruz, Mexico, Southern Gulf of Mexico

A helminthological examination was performed on 114 specimens of sciaenids that were captured on the Alvarado coast, Veracruz, Mexico, between August 2004 and July 2006. Bairdiella chrysoura (n = 15); Cynoscion arenarius (n = 31); Menticirrhus americanus (n = 16); Menticirrhus littoralis (n = 33) and Umbrina coroides (n = 19). 26 parasites were identified at the species, 12 genus and 5 family levels, as follows: 21 digeneans (14 adults and 7 metacercariae), 9 monogeneans, 7 nematodes (4 adults and 3 larvae), 2 cestodes (larvae), and 4 acanthocephalans (adults). Digeneans and monogeneans were the most abundant. Helminths with the highest prevalence in all five communities were Pseudorhamnocercoides stichospinus and Tetraphyllidae. The species with highest mean intensity were Diplomonorchis leiostomi and Tetraphyllidae, and Hysterothylacium sp., were registered in the five communities. Significant correlations between the host total length and species richness, U. coroides (r = 0.54), and total length and abundance, M. americanus (r = 0.63), were found. The highest similarity was recorded among communities of M. americanus and M. littoralis. The infracommunities and component communities in species richness and diversity, in all cases, were within ranges observed in most marine fish helminth communities.

Comparison of anisakid infection levels between two species of Atlantic mackerel (<em>Scomber colias</em> and <em >S. scombrus</em>) off the Atlantic Portuguese coast

Anisakiasis is a problematic zoonotic infection associated with the consumption of raw or undercooked fish. Atlantic mackerel (Scomber colias) is of high commercial interest in Portugal and has been reported as a common host of Anisakisspp. In this study, the occurrence of anisakids is evaluated in S. colias and also Scomber scombrus, and the potential zoonotic risk associated with consumption of these two fishes is evaluated according to the recorded infection levels. These were found to be high for both fish species: a mean intensity and prevalence of 21.7 worms/fish and 85% for S. colias, and 16.4 worms/fish and 83.3% for S. scombrus, respectively. No correlation was detected between anisakid intensity and host total length, total weight, condition factor, and hepatosomatic and gonadosomatic indices for both fish species, but significantly higher intensity values were detected for more mature S. scombrus, i.e. fish recording a higher gonadosomatic index. Molecular tools allowed the identification of two species of Anisakis, A. simplex (s.s.) and A. pegreffii. They differed in their occurrence: in S. colias the prevalence of A. simplex (s.s.) was 18% and that of A. pegreffii was 82%, whereas in S. scombrus the prevalence of A. simplex (s.s.) was 73% and that of A. pegreffii was 27%. Occasionally, worms of Hysterothylacium aduncum were identified for both fish. The different infection levels of the two Anisakisspecies in both hosts off the Portuguese coast raise the hypothesis of a different life cycle at the level of the invertebrate intermediate host. S. colias lives in deeper waters than S. scombrus, and the differences found in infection levels suggest that A. pegreffii main first intermediate host also live in deeper waters, compared with A. simplex (s.s.) main first intermediate host. The higher infection levels of A. simplex (s.s.) (most infectious to humans) in S. scombrus suggest that its consumption when slightly cooked, as in grilled fish (so popular in Portugal), could be more problematic for the development of anisakiasis in humans than the consumption of S. colias and thus be of potential public health concern.

The first report of liver coccidian Goussia cruciata in jack mackerel, Trachurus murphyi, from the South Pacific and its relationship with host variables.

The liver coccidian Goussia cruciata is considered as a specific parasite of the genus Trachurus, but to date, this parasite has only been reported for Atlantic species (Trachurus picturatus, Trachurus lathami, Trachurus trachurus and Trachurus mediterraneus). Therefore, this is the first report of this parasite in a species of Trachurus from the South Pacific. The prevalence and abundance of this coccidian in jack mackerel, T. murphyi, was determined, and its relationships with host variables such as total body length, condition factor and hepatosomatic index were evaluated. A total of 49 individuals were sampled from a commercial vessel of the central Chilean coast (36° 41' S, 73° 06' W) in November 2013 and February and May 2014. The parasite was identified by means of liver smears using light microscopy. The relationship between the abundance of the parasites and the host total length, condition factor and hepatosomatic index was analysed with Spearman's correlations. The sporogonic stages exhibited sporocysts that were morphologically concordant with coccidian G. cruciata. All hosts were parasitised with this coccidian, and the abundance varied between 2 and 224 oocytes per host. The parasite abundance was negatively correlated with the host total length. Infection levels of G. cruciata in T. murphyi apparently do not produce negative effects on fish condition.

Metazoan parasites of Mugil curema (Osteichthyes: Mugilidae) from the coastal Rio de Janeiro

From May to August 2011, 55 specimens of white mullet Mugil curema Valenciennes, 1836 (Osteichthyes: Mugilidae) collected from coast of the State of Rio de Janeiro (21-23° S, 41-45° W), were necropsied to study their communities of metazoan parasites. Two species of metazoan parasites were collected: Floridosentis mugilis Machado, 1951 (Acantocephala: Neoechinorhynchidae) and Metamicrocotyla macracantha Alexander, 1954 (Monogenea: Microcotylidae). The majority of the fishes (n = 41; 74.5%) were parasitized by at least one metazoan species. Three hundred twenty-four specimens, with an average of 5.8 ± 7.6 per host, were collected. Floridosentis mugilis constituted the majority of specimens collected (n = 319), was the dominant species, with highest prevalence, abundance, intensity and mean intensity. The parasites species showed a typical over-dispersed pattern of distribution. The abundance of the species F. mugilis and total parasites collected showed negative correlation with host total length. The metazoan parasites community of M. curema showed dominance of endoparasites, no correlation between parasite abundance and the lack of relationship between the sex of host and parasite rates. Mugil curema showed low parasite species richness when compared with studies on the parasitic fauna of mugilids of the Brazilian coast.

Community ecology of the metazoan parasites of the Indian mackerel Rastrelliger kanagurta (Scombridae) from the coast of Visakhapatnam, Bay of Bengal

One hundred and eighty four specimens of the mackerel Rastrelliger kanagurta collected from fish landings at Visakhapatnam coast, Bay of Bengal, between January 2006 and 2007, were examined for analysis of their metazoan parasite community structure at infra and component community levels and study the effects of season and host body length on these communities. Fifteen species of metazoan parasites were collected including 3 spp. Monogenea, 7 spp. Digenea and 5 spp. Copepoda. All the fish were parasitized by one or more metazoan parasite species. A total of 2,004 parasites were collected with a mean of 10.9. The majority were digeneans accounting for 42.4% of total number of parasites collected and the hemiurid Lecithocladium angustiovum is found to be the most dominant species. Mean values of species richness (3.0±1.5), abundance (12.4±9.3) and diversity (H'=0.92) were within ranges observed for most of the metazoan parasite communities of marine fish from temperate and tropical countries. Seasonally, the mean diversity and parasite species richness of infracommunities were high during December and January and low during September-October. No correlation was found between host total length and any of the community descriptors. Most of the parasites i.e., 12 out of 15 species of parasites collected were host specialists. Only one species Aponurus laguncula was a host generalist. All taxa of metazoan parasites showed a typical over-dispersed pattern of distribution. The dominance of the core species in all the infracommunities and the high degree of host specialization of the parasite species resulted in the predictable component in the infracommunities to be high, each infra community comprising a core species accompanied by a few secondary species.

COMMUNITY STRUCTURE OF THE INTESTINAL HELMINTHS OF THE CHINESE HOOKSNOUT CARP,<I>OPSARIICHTHYS BIDENS</I>(G-NTHER),FROM THE <I>DANJANGKOU RESERVIOR</I>

Many parasite community structures in fish have been demonstrated non-random but the results were not consistent at any time. Some environmental factors and host traits are likely to influence the parasite community structure. Here, we address this question using data on the intestinal helminthes community of the Chinese hooksnout carp Opsariichthys bidens from the Danjiangkou Reservoir, China, and focus on the impactions caused by host body length and season variation.During the time from February 2004 to November 2005 848 specimens of O. bidens were collected and examined. In total, 14 species of the intestinal helminths were found: 7 nematodes,4 digeneans,2 acanthocephalans and I cestode. The result showed that 87.49% of O. bidens were parasitized by at least one parasite species and the mean intensity was 8.71 +/- 11.557. The mean infracommunity diversity was Brillouin index = 0.238 +/- 0.287. The infracommunity diversity showed significantly positive correlation with host's total length ( Spearman rank correlation coeffection r, = 0.09 p 0.05). The nematodes Carnallanus cotti and Rhabdochona cascadilla, the cestode Bothriocephalus acheilognathi, and the acanthocephalan Micracanthorhynchina motomurai with higher prevalence and intensity were the core species of this community. The infection intensities of the core species were significantly correlated with the host's body length (r, = 0.238, -0.159, 0.150, -0.115;p = 18 cm respectively, showed that the changes of diet and body length of the host had significant impact. The parasite community in host with longer body length inclined to have significantly interspecific correlation. Also the parasite community in summer and autumn show the same tendency.

ASPECTS OF BRANCHIAL PARASITISM IN BARBUS MERIDIONALIS PETENYI HECKEL, 1847(TELEOSTEI: CYPRINIDAE)

The present paper aims to analyze some ecological a spects of the branchial microhabitat in Mediterranean barbell ( Barbus meridionalis petenyi Heckel, 1847). In the autumn of 2006, we sampled 24 specimens belonging to this cyprinid by electrofish ing from the SomeBasin. The parameters calculated for the infestation with Paradiplozoon tisae Khotenovski, 1982, were: prevalence, mean intensit y and mean abundance. Regarding the monogeneans fixing sites, most of the m manifested obvious preference for: first branchia l arch, internal hemibranch, median zone. The conclusions were argued by using the Student's t test, which als o demonstrated that parasite distribution in the righ t branchial cavity was not significantly different from the left branchial cavity (p>0.05). Also, we discussed the r elationship between host total length and the inten sity of infection. This is the first record for Paradiplozoon tisae in the Romanian fauna.

Ecologia da comunidade de metazoários parasitos do pargo, Pagrus pagrus (L., 1758) (Osteichthyes, Sparidae) do litoral do Estado do Rio de Janeiro, Brasil

Ninety specimens of red porgy, Pagrus pagrus (Linnaeus, 1758) (Osteichthyes: Sparidae) collected from the coastal zone of the State of Rio de Janeiro, Brazil (21-23 o S, 41-45 o W), from October 1998 to March 2000, were necropsied for parasite studying. All fish were parasitized by metazoan. Twenty-two species of parasites were collected. The nematodes were 59% of the total parasitic specimens number. Contracaecum sp. larvae were the dominant species with highest prevalence and abundance. Abundance and prevalence of cymothoid isopod were positively correlated with host total length, while the prevalence of Parahemiurus merus (Linton) and Polymorphus sp. were negatively correlated with host total length. The host gender did not influence any parasite species prevalence or abundance. The mean diversity in the P. pagrus infracommunities was H=0.306±0.119, with no correlation with the host’s total length and no significant difference between male and female fish. Three pairs of species shared a significant positive covariation, and two pairs shared significant positive association between their abundances and prevalences, respectively. Negative parasite species association or covariation were not found. Qualitative similarity was observed between the ectoparasite infracommunities of P. pagrus , at the genus level, with other sparid fishes of the world.

Community ecology of the metazoan parasites of namorado sandperches, Pseudopercis numida Miranda-Ribeiro, 1903 and P. semifasciata Cuvier, 1829 (Perciformes: Pinguipedidae), from the coastal zone of the State of Rio de Janeiro, Brazil

One hundred and twenty-eight specimens of namorado sandperches, 62 P. numida and 66 P. semifasciata, collected between October 2002 and June 2003 off the Cabo Frio, Rio de Janeiro, Brazil (Lat 23 degrees S and Long 42 degrees W), were examined to study their metazoan parasites. Parasite communities of these fish were composed basically of endoparasites, mainly digenean and cestodes species, with low prevalence and abundance but having high parasite species richness values (at the component community level). Among these values, that found for P. numida is the highest so far recorded for marine fishes from the Neotropical Region. Thirty-nine species of metazoan parasites were collected: 36 from P. numida and 28 from P. semifasciata. Twenty-five parasite species were common to both species of namorado sandperches. Pseudopercis numida and P. semifasciata are new host records for all parasite species collected, with the exception of Microcotyle pseudopercis. Choanodera sp., Leurodera decora, Neolebouria georgenascimentoi, and Proctoeces sp. which were recorded for the first time in the South American Atlantic Ocean. Gnathia sp. from P. numida and Scolex pleuronectis from P. semifasciata were the species having the greatest dominance frequency. Parasite abundance in P. numida and P. semifasciata were positively correlated with the host total length. Only in P. numida was parasite species richness correlated positively with the host total length. No significant differences between endoparasite infracommunities of P. numida and P. semifasciata were detected. The ectoparasites of P. numida had higher values for parasite abundance, parasite richness, Brillouin index, evenness index, and Berger-Parker index than those of the ectoparasites of P. semifasciata. Comparisons among all ecto- and endoparasites showed the ectoparasites of P. numida as the most heterogeneous group. Low similarity values were observed among the three types of parasite infracommunities of the two hosts.

Demodectic Mange in a White-Tailed Deer from Walker County, Texas

The first documented occurrence of demodectic (Acari: Prostigmata: Demodicidae) mange in white-tailed deer, Odocoileus virginianus Zimmerman, in Texas was diagnosed from deep skin scrapings taken from the neck, shoulders, and withers of a fair-to-poor condition 6 yr-old male deer captured at Elkins Lake (latitude 30 degrees 39' 27" N, longitude 95 degrees 32' 33" W), Walker County. Approximately 35% of the animal's skin showed effects of the demodicosis, which may have contributed to the animal's body condition. The hematology of the infected deer seemed little altered from mean erythrocyte and leukocyte values of the local deer population, except for an observed eosinophilia (23% increase), which is consistent with an ectoparasitic infection and the concomitant bacterial infection observed. Predicated on host specificity and total body length measurements, Demodex odocoilei Desch & Nutting is probably the parasite collected from the captured white-tailed deer.

Metazoários parasitos de seis espécies de peixes do Reservatório de Lajes, Estado do Rio de Janeiro, Brasil

From April 2002 to July 2003, 231 freshwater fishes from Lajes Reservoir in the State of Rio de Janeiro, Brazil (22 degrees 42' - 22 degrees 50'S, 43 degrees 53' - 44 degrees 05'W) were necropsied to study their community metazoan parasites: 39 Astyanax bimaculatus (Linnaeus, 1758), 79 A. fasciatus (Cuvier, 1819), 23 Hypostomus affinis (Steindachner, 1877), 26 Hoplias malabaricus (Bloch, 1794), 30 Loricariichthys castaneus (Castelnau, 1855) and 34 Trachelyopterus striatulus (Steindachner, 1876). The majority of specimens of H. affinis (95.6%) and H. malabaricus (84.6%) was parasitized by one or more metazoan species. In A. bimaculatus, A. fasciatus, L. castaneus and T. striatulus 41%, 39.2%, 56.7 and 14.7% of specimens were parasitized, respectively. Eight different metazoan parasites species were collected: 2 in A. bimaculatus, 3 in A. fasciatus, 3 in H. affinis, 4 in H. malabaricus, 4 in L. castaneus and 1 in T. striatulus. The parasites of the six host species showed the typical aggregated pattern of distribution. Two cases of negative correlation between host's total length and prevalence and parasite abundance were detected. The parasite community of L. castaneus showed the higher values of mean intensity, index of dispersion and higher values of diversity. The parasite communities of the studied fishes showed scarcity of significant correlations of parasitic abundance, species richness and diversity with the size of the host. The low species richness and diversity of parasite communities could be originated by the oligotrophic characteristics of the Lajes Reservoir.

Community ecology of metazoan parasites of the anchovy Anchoa tricolor (Osteichthyes: Engraulidae) from the coastal zone of the State of Rio de Janeiro, Brazil

Between October 2001 and March 2002, 103 specimens of A. tricolor from Angra dos Reis (23 degrees 01' S, 44 degrees 19' W), in the coastal zone of the State of Rio de Janeiro, Brazil, were analyzed in order to study their metazoan parasite infracommunities. Ten species of metazoan parasites were collected: 4 digeneans, 1 cestode, 1 acantocephalan, 2 nematodes, 1 copepod, and 1 hirudinean; 77.7% of the fishes were parasitized by one or more metazoan, with a mean of 3.5 +/- 6.2 parasite/fish. Digenean was the most dominant with 4 species that accounted for 53.2% of the total parasites collected; Ergasilus sp. was the most abundant species. Abundance and prevalence of Parahemiurus merus (Linton, 1910) were positively correlated with the total length of host. Relationships between total body length of fish and both total parasite abundance and mean parasite species richness were observed. Mean parasite diversity of species was correlated to host's total length, with significant differences found between male and female fishes. Two pairs of larval species showed significant positive association and covariation. The metazoan parasite infracommunities of A. tricolor presented dominance of larval endoparasites; correlation of parasite abundance, diversity, and species richness with host total length; and low number of parasite interspecific relationships. The parasite community of A. tricolor showed some similarities with the parasite community of another South American Atlantic engraulid.

Size Variation of Adult Polyopisthocotylid Metamicrocotyla macracantha (Monogenea) in Relation to Host Size

Abstract Growth of the polyopisthocotylid monogenean Metamicrocotyla macracantha was studied in relation to the size of its host, the striped mullet Mugil cephalus. Forty-nine adult monogeneans were collected; total length, body length, haptor length, and clamp widths were measured and compared with host total length. Although no significant correlation between these size parameters of M. macracantha and that of the host was found, the haptor of the worm was found to reach a maximum length while its body continued to elongate. Such a growth pattern may be indicative of a less-efficient haptor resulting in the unique coiling behavior of M. macracantha.

Metazoários parasitos do coió Dactylopterus volitans (Linnaeus, 1758) (Osteichthyes: Dactylopteridae) do litoral do Estado do Rio de Janeiro, Brasil

Seventy-eigth specimens of Dactylopterus volitans (Linnaeus,1758) collected from the coastal zone of the State of Rio de Janeiro (21-23º S, 41-45º W), Brazil, from December 2002 to January 2003, were necropsied to study their metazoan parasites. Twenty-seven species of parasites were collected: 1 aspidogastrean, 15 digenean, 1 monogenean, 2 cestodes, 2 acantocephalan, 4 nematodes, 1 branquiuran, and 1 isopod. All parasite species were recorded by the first time in D. volitans. The acanthocephalan Rhadinorhynchus sp. was the most dominant species with the highest prevalence in the parasite community of D. volitans. Opecoeloides sp. showed positive correlation between the host total length and parasite prevalence, while Rhadinorhynchus sp. have a negative correlation between the host´s total length and prevalence. One pair of endoparasite species (Dinurus sp.- Lecithochirium sp.) showed positive covariation between their abundances. As other parasite communities of benthic fishes from Rio de Janeiro, the parasite community of D. volitans is apparently a little−ordered species complex, characterized by the dominance of the endoparasite species

Community ecology of the metazoan parasites of Atlantic Moonfish, Selene setapinnis (Osteichthyes: Carangidae) from the coastal zone of the state of Rio de Janeiro, Brazil

Eighty-nine specimens of Selene setapinnis (Mitchill, 1815) collected from the coastal zone of the State of Rio de Janeiro (21-23 degrees S, 41-45 degrees W and 23 degrees 05'S, 44 degrees 30'W), Brazil, from August 2001 to May 2002, were necropsied to study their metazoan parasites. Eighty-one (91%) specimens of S. setapinnis were parasitized by one or more metazoan species. Twenty-one species of parasites were collected: 8 digeneans, 3 monogeneans, 2 cestodes, 5 nematodes, and 3 copepods. The endoparasites (digeneans, cestodes, and nematodes) were 74.1% of total number of parasite specimens collected. The monogenean Pseudomazocraes selene (Hargis, 1957) was the most dominant species with the highest prevalence in the parasite community of S. setapinnis. The metazoan parasites of this host species showed the typical aggregated pattern of distribution. Only one parasite species (Acanthocolpoides pauloi Travassos, Freitas & Buhrnheim, 1955) showed positive correlation between the host total length and parasite abundance in S. setapinnis. Caligus robustus Bassett-Smith, 1898, P. selene, and Terranova sp. demonstrated positive correlation between the host total length and prevalence. Larvae of Terranova sp. showed influence of the host sex on its prevalence. A pair of ectoparasite species, P. selene-C. robustus, exhibited positive covariation between their abundances. Two pairs of endoparasite species, L. microstomum-P. merus and A. pauloi-P. merus showed significant covariation among their abundances; and the pair Terranova sp.-Raphidascaris sp. had positive co-ocorrence and covariation in the infracommunities of S. setapinnis. Like the parasite communities of the other carangid fishes from Rio de Janeiro, the parasite community of S. setapinnis is apparently only a slightly ordered species complex, characterized by dominance of endoparasite species.

Community ecology of the metazoan parasites of white sea catfish, Netuma barba (Osteichthyes: Ariidae), from the coastal zone of the state of Rio De Janeiro, Brazil.

Between March 2000 and April 2001, 63 specimens of N. barba from Angra dos Reis, coastal zone of the State of Rio de Janeiro (23 degrees 0' S, 44 degrees 19' W), Brazil, were necropsied to study their infracommunities of metazoan parasites. Fifteen species of metazoan parasites were collected: 2 digeneans, 1 monogenean, 2 cestodes, 1 acantocephalan, 2 nematodes, 6 copepods, and 1 hirudinean. Ninety-six percent of the catfishes were parasitized by at least one metazoan parasite species. A total of 646 individual parasites was collected, with mean of 10.3 +/- 16.6 parasites/fish. The copepods were 37.5% of the total parasite specimens collected. Lepeophtheirus monacanthus was the most dominant species and the only species with abundance positively correlated with the host total length. Host sex did not influence parasite prevalence or mean abundance of any species. The mean diversity in the infracommunities of N. barba was H = 0.130 +/- 0.115 with no correlation with host's total length and without differences in relation to sex of the host. One pair of endoparasites (Dinosoma clupeola and Pseudoacanthostomum floridensis) showed positive association and covariation between their abundances and prevalences. The parasite community of N. barba from Rio de Janeiro can be defined as a complex of species with low prevalence and abundance and with scarcity of interspecific associations. However, because of both the presence of assemblages of sympatric ariid species as well as the spawning behavior characteristic of these fishes, additional comparative studies of the parasite component communities of ariids are necessaries to elucidate this pattern.

Ecologia da comunidade de metazoários parasitos da Maria-Luiza, Paralonchurus brasiliensis (Osteichthyes: Sciaenidae) do litoral do Estado do Rio de Janeiro, Brasil

Ninety-three specimens of banded croaker, Paralonchurus brasiliensis (Steindachner, 1875), collected from Pedra de Guaratiba (23º01’S, 43º38’W), coastal zone, State of Rio de Janeiro, Brazil, between September 2001 and March 2002, were necropsied to study their infracommunities of metazoan parasites. Fifteen species of metazoan parasites were collected. Paralonchurus brasiliensis is a new host record for 13 parasite species. The majority of fishes were parasitized by one or more metazoan. Larvae of Contracaecum sp. proved to be the dominant species, with highest prevalence and abundance values. The parasite species of P. brasiliensis showed the typical aggregated distribution pattern. Prevalence and abundance of Procamallanus (Spirocamallanus) pereirai was positively correlated with the host total length. Abundance of Contracaecum sp. was positively correlated with the host total length. The abundances of a pair of adult endoparasites (Aponurus laguncula - Procamallanus (S.) pereirai) showed negative covariation and one pair of larvae stages of endoparasites (Nybelinia sp. – Contracaecum sp.) showed positive covariations between their abundances. Paralonchurus brasiliensis showed a metazoan parasite community composed by generalist species, little ordered and with scarce quantitative evidences of interspecific associations. These patterns agree with those detected in preceding studies about the parasite communities of Neotropical sciaenid fishes.

Sanguijuelas (Hirudinea: Glossiphoniidae) asociadas a Cryphiops caementarius (Decapoda: Palaemonidae) del Río Limarí, Chile

Leeches (Hirudinea: Glossiphoniidae) associated to Cryphiops caementarius (Decapoda: Palaemonidae) of the Limari river, Chile. Two leech species were found parasitizing the shrimp Cryphiops caementarius from Limari river, Chile. These ectoparasites can act as population regulators or development inhibitors in their host; however the biological characteristics of this host-parasite interaction are unknown. We analyze the inter-specific differences of the parasitism and its relation with host size and sex using quantitative descriptors. Abundance, prevalence, intensity and range were estimated with respect to host size and sex. The leeches belong to two species of Glossiphonidae: Helobdella triserialis and H. duplicata. Forty-seven percent of the hosts were parasitized by one or both leech species. H. triserialis was found only in the pleopod of the hosts with the highest prevalence values (42 %), intensity (2.9) and range (1-11). H. duplicata was found only in the branchial filaments with 7 % prevalence, an intensity of 1.7 and a range of 1-4. The host's total length and sex can explain the variation in leech intensity and infection prevalence. However, when only the host's sex is considered, prevalence only increased with size in female hosts. Morphological characteristics of the females could explain the greater H. triserialis intensity in the base of the pleopod and would be related to a greater abdomen development. Rev. Biol. Trop. 55 (1): 255-260. Epub 2007 March. 31.