Seasonality and historic trends in the reef fisheries of Pulau Banggi, Sabah, Malaysia

The reef fisheries of Pulau (meaning “island” in Malay) Banggi, Sabah are not managed, and lack baseline fisheries data despite forming part of a proposed marine park. Thus, a combination of qualitative and quantitative approaches was applied to obtain a baseline picture about the past and present state of the fisheries. Fish landings were monitored, and fisher interviews conducted to investigate seasonal effects and historical changes in Banggi’s reef fisheries. Monsoon winds were a major driver of seasonal differences in catch quantities for the hook and line, but not the gillnet fishery. Spatial distribution of fishing effort and target species also differed by season. Fishers consistently indicated that Banggi’s fisheries were declining, with a suggested three to four times decrease in catch rates over the last 20 years. Interestingly, it appeared that substantial decreases began in the year 2000. The responses of fishers to seasonal changes, and the resultant implications for management are discussed. Importantly, the need for immediate management policies to prevent further declines and to maintain sustainable reef fisheries is stressed. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

The metazoan parasites of Stellifer minor (Tschudi, 1844): an ecological approach

A quantitative and qualitative analysis of the parasite fauna of the sciaenid Stellifer minor (Tschudi) from Chorrillos, Perú, was made. Some characteristics of the infectious processes, in terms of intensity and prevalence of infection, as a function of host sex and size, are given. Moreover, comments on the characteristics of the parasite fauna, related with host role in the marine food webs are included. The parasite fauna of Stellifer minor taken off Chorrillos, Perú, include the monogeneans Pedocotyle annakohni, Pedocotyle bravoi, Rhamnocercus sp. and Cynoscionicola sp., the digenean Helicometra fasciata, the adult acantocephalan Rhadinorhynchus sp. and the larval Corynosoma sp., the nematode Procamallanus sp., the copepods Caligus quadratus, Clavellotis dilatata and Bomolochus peruensis and one unidentified isopod of the family Cymothoidae. A distinctive characteristic of the parasite fauna (Metazoa) of S. minor is the almost absence of larval forms.     

Aquatic pollution assessment based on attached diatom communities in the Pinang River Basin,Malaysia

The diatom communities collected from artificial substrates (glass slides) at 12 sampling sites along Pinang River Basin were analysed. Species composition was highly variable among sampling sites, and the highest diversity value (mean H = 3.56 bit/individual) and species richness (mean S = 17.32) was recorded at a polluted station in an estuary, which received salt-water intrusion during high tide. The downstream sampling stations were heavily organically polluted with Saprobic Index values ranging between 2.81 and 3.10, while upstream stations were relatively clean with Saprobic Index values recorded between 1.40 and 1.96. The diatom community structure and the specific sensitivity of certain diatom species can be related to the degree of water quality in Pinang River Basin. The abundance of certain diatom species could be used as biological indicators to measure impacts of river pollution.     

Influence of collection methods on the occurrence of alimentary canal helminth parasites in fish.

The effect of collecting trauma on the metazoan parasites in the alimentary canal of French grunts, Haemulon flavolineatum (Desmarest) (Perciformes: Haemulidae), was evaluated by comparing the number and species of parasites in 10-fish lots that were identical except for collecting technique. Collecting techniques included speared (dead), speared through the caudal peduncle (live), trapped, dipnetted at night, and ostracitoxin exposed. Dead, trapped, and toxin-stressed fish had no alimentary canal parasites, whereas speared-live and night-dipnetted fish had comparable numbers of parasites. Fish collected by using apparently traumatic techniques quickly expelled their alimentary canal metazoan parasites. Our results cast doubt on the reliability of traditional fish parasite surveys, studies on population dynamics of fish parasites, and experiments that employ these traumatic collecting methods.     

Communities of metazoan parasites in open water fishes of Cold Lake, Alberta

Communities of metazoan parasites in ten species of fishes from Cold Lake, Alberta are described and compared. Relative abundances in the overall community of parasites in the lake were estimated using data on abundance in each host species, plus estimates of the relative abundances of the species of hosts. Parasites of the numerically dominant salmonid fishes dominated the overall community, with over half of the individual parasites being Metechinorhynchus salmonis . Exchange of parasites between host species was greatest between related and/or abundant host species. Parasite communities in cisco and whitefish, Coregonus spp., were relatively rich in species and diverse (Simpson's index) compared with communities in those species in other lakes in North America; communities in lake trout, Salvelinus spp., and the non-salmonid fishes were poor in species and low in diversity compared with communities in other lakes. Parasite species overlaps (Jaccard index) between related host species in Cold Lake were greater than overlaps within host species between lakes. The same pattern is seen in data from some other lakes. These features support the hypothesis of Wisiewski (1958); that the parasite community within an ecosystem is characterized by parasites of the numerically dominant hosts.     

The metazoan parasites of freshwater fishes in the Corrib catchment area, Ireland

A survey of the parasites of 243 fish belonging to 13 species, from the Corrib catchment area, western Ireland, was undertaken. At least 32 species of metazoan parasites were shown to be present. Diplostomum gasterostei, Tylodelphys clavata, Eubothrium salvelini, Cucullanus truttae, Raphidascaris acus, Ergasilus gibbus and Salmincola gordoni appear to be first records for Ireland and Phyllodistomum conostomum has not previously been reported from the British Isles. New host records involving Lamptera planeri, Salvelinus alpinus, Abramis brama, Noemacheilus barbatulus, Anguilla anguilla and Pungitius pungitius for the British Isles are given.     

Leachate Characterization and Phytoremediation Using Water Hyacinth (Eichorrnia crassipes) in Pulau Burung,Malaysia

Leachate from Pulau Burung landfill site was analyzed and treated using phytoremediation technique while water hyacinth (Eichhornia crassipes) was used as the phytoremediator. Some parameters analyzed included ammonia nitrogen (NH₃-N), nitrate, nitrite, total Kjeldahl nitrogen (TKN), phosphate, and zinc. The range of values of nutrients such as the pH, ammonia nitrogen, TKN, phosphate and zinc during leachate characterization were 8.72 and 8.58, 1810 and 1070 mg/L, 1183 and 1120 mg/L, 46.4 and 31.2 mg/L, 11.1 and 5.4 mg/L, respectively. After phytoremediation, significant reduction was noticed in all the nutrients and zinc. Nitrite, phosphate and zinc values were between 91.9% and 98.2%, 4.4 to 0.6 mg/L and 1.1 and 0.1 mg/L, respectively. Statistical analyses showed significant differences between the planted and unplanted systems (p ≤ .05). It was established that Eichhornia crassipes had the capacity to remove nutrients and heavy metals from leachate, which requires treatment to minimize pollutants to an acceptable level before discharging into water courses.     

Macvicaria taksengi n. sp. (Digenea: Opecoelidae) in marine teleosts from Pinang,Malaysia

Summary A new species, Macvicaria taksengi (Opecoelidae: Plagioporinae), is described from the fishes Otolithes ruber and Sillago sihama from Pinang, Malaysia. It differs from most other members of the genus in the position of the ovary relative to the testes and the anterior position of the genital pore. A brief discussion on the Indo-West Pacific forms of the genus Macvicaria and related genera includes references to several new combinations: M. [Lebouria] isaitschikowi (Layman, 1930), M. [Plagioporus] sillagonis (Yamaguti, 1938), M. [Plagioporus] chrysophrys (Nagaty & Abdel Aal, 1969) and M. [Plagioporus (Plagioporus)] longisaccus (Fischthal & Kuntz, 1964).     

Biogeographic patterns of metazoan parasites of the bigeye flounder, Hippoglossina macrops, in the southeastern Pacific coast

We examined the metazoan parasite fauna of the bigeye flounder, Hippoglossina macrops, in a latitudinal gradient of the southeastern Pacific (ca. 25 degrees S-33 degrees S) to assess whether their parasites show latitudinal and/or biogeographical patterns, and to determine if these patterns agree well with those observed for free-living organisms. In total, 331 fish from 6 localities were analyzed. Eighteen parasite species, including 5 ecto- and 13 endoparasites, were found in the bigeye flounder. Neoheterobothrium chilensis, Floridosentis sp., and Corynosoma australe were the most prevalent parasite species. Ecto- and endoparasites of H. macrops showed different latitudinal patterns. Only endoparasite species show a distributional pattern concordant with biogeographic areas recognized for free-living organisms; this finding was supported by cluster analyses showing 2 major divisions. The first joined the most northern localities (25 degrees S-26 degrees S), and the second consisted of 2 subgroups: (1) 28 degrees S-30 degrees S, and (2) 31 degrees S-32 degrees S. A multivariate analysis of infracommunities showed significant differences in the parasitic load of H. macrops from different latitudes. The latitudinal differences in the prevalence and abundance of the parasites might be explained by differing oceanographic conditions in water masses. These physical conditions could affect the dispersal ability of the infective stages of ecto-parasites, and produce zoogeographical breaks that could affect the distribution of intermediate hosts (invertebrate and vertebrate prey), subsequently affecting the transmission of endoparasites.     

Notes on the occurrence of the tropical eel Anguilla bicolor bicolor in Peninsular Malaysia, Malaysia

Previous studies indicated that a tropical freshwater eel Anguilla bicolor bicolor occurs in Africa, India, Sri Lanka, Bangladesh, Myanmar, Indonesia and Australia, but an intensive survey has indicated an extended distribution range for the species into Peninsular Malaysia. Thus, A. b. bicolor is a native subspecies of Malaysia.     

First occurrence of Cochlodinium blooms in Sabah, Malaysia

Harmful algal blooms (HABs) resulting in red discoloration of coastal waters in Sepanggar Bay, off Kota Kinabalu, Sabah, East Malaysia, were first observed in January 2005. The species responsible for the bloom, which was identified as Cochlodinium polykrikoides, coincided with fish mortalities in cage-cultures. Determinations of cell density between January 2005 and June 2006 showed two peaks that occurred in March–June 2005 and June 2006. Cell abundance reached a maximum value of 6 × 10⁶ cells L⁻¹ at the fish cage sampling station where the water quality was characterized by high NO₃–N and PO₄–P concentrations. These blooms persisted into August 2005, were not detected during the north–east monsoon season and occurred again in May 2006. Favorable temperature, salinity and nutrient concentrations, which were similar to those associated with other C. polykrikoides blooms in the Asia Pacific region, likely promoted the growth of this species. Identification of C. polykrikoides as the causative organism was based on light and scanning microscopy, and confirmed by partial 18S ribosomal DNA sequences of two strains isolated during the bloom event (GenBank accession numbers DQ915169 and DQ915170).     

Local variability in metazoan parasites of the pelagic fish species, Engraulis ringens: implications for fish stock assessment using parasites as biological tags

Parasites have been used successfully as biological tags in population studies, mainly in marine fishes, but also in marine mammals, crustaceans and molluscs. Almost all published information dealing with parasites as biological tags evaluates differences between localities. However, local variability in the component community has not been assessed. In this work, we examined whether local variation of the metazoan parasite fauna of Engraulis ringens, extracted from five independent samples from two nearby localities in northern Chile, can be a factor causing bias in stock identification. Our results show that local variability, as estimated by a single sample, may suffice to represent component community variability with no need for replicated data.     

Comparison of metazoan parasites of Atlantic cod, Gadus morhua, from three geographical areas of coastal Newfoundland

This study compared metazoan parasites in the digestive tract of Atlantic cod, Gadus morhua , captured from 3 geographical areas off the northeastern (NE), southeastern (SE), and southwestern (SW) coasts of Newfoundland. Samples were obtained by line trawl and frozen after capture, and the digestive tract was subsequently examined for metazoan parasites following conventional parasitological methods. Mean abundance of nematodes, but not the trematodes, and an acanthocephalan was significantly greater in cod taken from the NE than from the SE or SW areas, which were generally similar. Four species of trematodes, 3 nematodes, and an acanthocephalan, Echinorhynchus gadi , were the dominant parasites observed. Differences in mean abundance among samples from different areas might be related to the types of prey consumed rather than to environmental factors. The dominant parasites were probably acquired by cod on the NE coast after feeding on capelin, Mallotus villosus , which serve as paratenic hosts for several helminth species. Previous studies on tagging, feeding, and prevalence of 3 parasites have revealed differences in the populations of cod from the NE than from the SW or SE areas. Results from the present study, indicating geographical differences in parasite mean abundance and prevalence from the digestive tract of Atlantic cod between SW and NE areas, support the view of distinct coastal cod stocks off Newfoundland.     

Guide to the identification of fish protozoan and metazoan parasites in stained tissue sections

The identification of protozoan and metazoan parasites is traditionally carried out using a series of classical keys based upon the morphology of the whole organism. However, in stained tissue sections prepared for light microscopy, taxonomic features will be missing, thus making parasite identification difficult. This work highlights the characteristic features of representative parasites in tissue sections to aid identification. The parasite examples discussed are derived from species affecting finfish, and predominantly include parasites associated with disease or those commonly observed as incidental findings in disease diagnostic cases. Emphasis is on protozoan and small metazoan parasites (such as Myxosporidia) because these are the organisms most likely to be missed or mis-diagnosed during gross examination. Figures are presented in colour to assist biologists and veterinarians who are required to assess host/parasite interactions by light microscopy.     

Testing local-scale panmixia provides insights into the cryptic ecology, evolution, and epidemiology of metazoan animal parasites

When every individual has an equal chance of mating with other individuals, the population is classified as panmictic. Amongst metazoan parasites of animals, local-scale panmixia can be disrupted due to not only non-random mating, but also non-random transmission among individual hosts of a single host population or non-random transmission among sympatric host species. Population genetics theory and analyses can be used to test the null hypothesis of panmixia and thus, allow one to draw inferences about parasite population dynamics that are difficult to observe directly. We provide an outline that addresses 3 tiered questions when testing parasite panmixia on local scales: is there greater than 1 parasite population/species, is there genetic subdivision amongst infrapopulations within a host population, and is there asexual reproduction or a non-random mating system? In this review, we highlight the evolutionary significance of non-panmixia on local scales and the genetic patterns that have been used to identify the different factors that may cause or explain deviations from panmixia on a local scale. We also discuss how tests of local-scale panmixia can provide a means to infer parasite population dynamics and epidemiology of medically relevant parasites.     

Seasonal occurrence of rotavirus in sewage.

A seasonal distribution was observed for rotaviruses in sewage by using indirect immunofluorescence. Levels were low from May through September and generally higher during winter and spring. In contrast, no seasonal pattern was observed for total enteroviruses. Limitations of the indirect immunofluorescence assay and enzyme immunoassay for environmental samples are discussed.     

Seasonal and ontogenetic dynamics in trophic transmission of parasites

Transmission rates from the intermediate (amphipods) to the definitive hosts (fish) were quantified for two helminth species ( Cyathocephalus truncatus , Cestoda, and Cystidicola farionis , Nematoda) both seasonally and through the ontogeny of the final hosts (arctic charr, Salvelinus alpinus , and brown trout, Salmo trutta ). Amphipods ( Gammarus lacustris ) were important prey for both fish species, especially in the autumn. Both parasite species had low infection levels in amphipods compared to high abundance in fish. The seasonal variations in transmission rate of C. truncatus procercoids from amphipods to fish were in accordance with the observed abundance in fish hosts, being highest in the autumn and lowest during late winter and early summer. During summer, however, the estimated monthly transmission rates of C. truncatus were higher than the observed infection levels in the fish, suggesting restricted establishment success and shorter development time and longevity of the cestode in fish at higher temperatures. The accumulated transmission of C. farionis over the ontogeny of arctic charr was similar to the observed age-specific infection levels, reflecting a high establishment success and longevity of this parasite in charr. In contrast, brown trout exhibited an infection level that was much lower than the estimated transmission rates, suggesting a high resistance against C. farionis in these fish. The magnitudes of the estimated transmission rates were sufficient to explain the paradoxical contrast between low infection levels in the intermediate and high in the final hosts.     

Rainfall induces time-lagged changes in the proportion of tropical aquatic hosts infected with metazoan parasites

Rainfall serves as a powerful driving force, shifting temporal abundance and prevalence patterns in parasites and free-living aquatic organisms in tropical environments. However, there is a lack of sound evidence showing the temporal scales at which rainfall influences infection parameters of parasites in the tropics either directly by affecting the parasite life cycle or indirectly by modifying host population abundance. In the present study, we demonstrate that changes in rainfall patterns lead to changes in the proportion of infected hosts with several parasite species, causing immediate or lagged favourable conditions for an increase in levels of infection. However, the temporal scale of the influence of rainfall varied depending on the ecological characteristics of aquatic ecosystems. Despite the environmental heterogeneity and stochastic events (storms and hurricanes) which affect the study sites, the proportion of infected hosts shows frequency cycles on a yearly scale, suggesting that environmental changes are within the range of variability that naturally occur at the study sites. We propose that the incorporation of stochastic events into long-term predictive models is crucial for understanding the potential effects of global climate change on infection parameters of tropical parasites.     

Potential interactions between metazoan parasites of the Mayan catfish Ariopsis assimilis and chemical pollution in Chetumal Bay,Mexico

The effect of pollutants on the intensity of infection of metazoan parasites in the Mayan catfish, Ariopsis assimilis was investigated. Data were collected on pollutants and metazoan parasites from 76 catfish from five localities in Chetumal Bay in October, 1996. Nineteen pollutants (pesticides, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs)) were found in the catfish livers. Heavy metal content was not determined. Nineteen metazoan parasite species were recovered. After controlling for fish length and sampling station, there was a significant negative linear relationship between the intensity of the larval digenean Mesostephanus appendiculatoides and 1,1,1,-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) concentrations. This negative relationship may be explained either by the effect of the pesticide on the mortality of (i) free-living larval forms, (ii) metacercariae in the fish, (iii) infected fish or (iv) intermediate host snails. There were significant differences between fish parasitized and not parasitized with M. appendiculatoides with respect to their DDT concentrations. There were also significant differences between the variances of the mean Clark's coefficient of condition values between catfish parasitized and not parasitized by M. appendiculatoides, with the variance of non-parasitized catfish being significantly larger. The results provided statistical evidence that DDT has a detrimental effect on M. appendiculatoides infection intensity. Furthermore, the significantly larger variance value of Clark's coefficient for non-parasitized fish suggested that DDT affects both the parasite and general host condition.