Intertidal sand‐dwelling Peracarid fauna of Stewart Island

Abstract

The distributions of infaunal Peracarida (Crustacea) and their correlation with sediment type, tidal height, and degree of exposure were studied in winter (June) at five beaches on Stewart Island, New Zealand. The beaches were selected lo cover a range of exposures to wind and wave action and substrate sorting. Substrate and infauna samples were taken at four tidal levels from each, with a 0.0625 m² quadrat.

Sieve separation and statistical analysis of the substrate samples indicated predominantly sand‐sized particles from all beaches, with median diameters in the range +1.52 to +2.92 ? (phi) units. Substrates were well sorted throughout the size range: ? quartile deviation ranged from 0.26 to 0.71, skewness from —0.18 to +0.07 ?.

Peracarid fauna was generally abundant, with a maximum of 29 136 per m²sampled in a more sheltered beach. Cumacea was the most abundant group, followed by Amphipoda, Isopoda, and Tanaidacea; dominance followed a similar sequence, being 78%, 19%, 2% and 1% respectively. Frequency of occurrence at the 19 stations was headed by Amphipoda (100%), with Isopoda 53%, Cumacea 32% and Tanaidacea 11%.     

Size composition of Jack mackerel catches from the west coast of New Zealand

Catches of iack mackerel Trachurus declivis taken everv 2 months from the west coast of New Zealand show that this species attains lengths of approximately 11 cm and 24 cm at the completion of the first and second years of life respectively. Above these lengths, year classes overlap considerably. Juveniles were found from Westland to North Cape and were most abundant in surface waters.     

Bivalve population health: Multistress to identify hot spots

This study investigated some stress (metals, parasites) and response (immunity, metallothionein) factors in two cockle and two Manila clam populations. Data from eight seasons were averaged to obtain global baseline values. Stress/response characteristics of each population were compared to population health status that was determined through population dynamics parameters. Four different scenarios were discussed: (1) a lightly stressed cockle population with correct population health but with a risk of deterioration (hot spot); (2) a lightly stressed introduced cockle population threatened of extinction. In this case ecological factors were suspected; (3) a moderately stressed clam population with moderate adaptative response. The population was sustainable but the level of stress should not increase (hotspot); and (4) a stressed clam population and unfavourable ecological conditions preventing clam settlement. This monitoring highlighted that the discrepancy between population health and stress levels could be due to insufficient response by bivalves and/or by unfavourable ecological factors.     

Hepatic histopathology in two populations of the mummichog, Fundulus heteroclitus

The pollution-tolerant mummichog, Fundulus heteroclitus, inhabits a heavily contaminated estuary, Piles Creek (PC), in Linden, NJ. PC contaminants include PAHs, PCBs and many metals, including high Hg and Pb. PC mummichog livers and kidneys were compared with those from a pristine estuary in Tuckerton (TK), NJ, by standard histopathological methods, with quantification by computerized image analysis. PC livers had>2× the lipid ratios of TK livers. Cell sizes and shapes were not different between populations. TK livers had a 25% incidence of basophilic areas and an age-related 30% incidence of macrophage aggregates; PC livers had none of these lesions. PC livers had a 100% incidence of necrotic foci, compared with 55% of TK livers. Inflammation was noted in 50% of TK livers but only 27% of PC livers. Curiously, the TK livers had a 45% incidence of metacercarial cysts of a digenetic trematode, while none were found in the PC livers. The TK focal necrosis and macrophage aggregates coincided with parasite infestation. There were no observed kidney lesions in either population. Positive biomarkers in this species thus included high hepatic lipid content, possibly necrosis, but no other lesions. The lack of trematode cysts in PC livers may reflect the lack of an intermediate host in this low biodiversity estuary.     

Cryptosporidium and Giardia in tropical recreational marine waters contaminated with domestic sewage: Estimation of bathing-associated disease risks

Sewage is a major contributor to pollution problems involving human pathogens in tropical coastal areas. This study investigated the occurrence of intestinal protozoan parasites (Giardia and Cryptosporidium) in tropical recreational marine waters contaminated with sewage. The potential risks of Cryptosporidium and Giardia infection from recreational water exposure were estimated from the levels of viable (oo) cysts (DIC+, DAPI+, PI−) found in near-shore swimming areas using an exponential dose response model. A Monte Carlo uncertainty analysis was performed in order to determine the probability distribution of risks. Microbial indicators of recreational water quality (enterococci, Clostridium perfringens) and genetic markers of sewage pollution (human-specific Bacteroidales marker [HF183] and Clostridium coccoides) were simultaneously evaluated in order to estimate the extent of water quality deterioration associated with human wastes. The study revealed the potential risk of parasite infections via primary contact with tropical marine waters contaminated with sewage; higher risk estimates for Giardia than for Cryptosporidium were found. Mean risks estimated by Monte Carlo were below the U.S. EPA upper bound on recreational risk of 0.036 for cryptosporidiosis and giardiasis for both children and adults. However, 95th percentile estimates for giardiasis for children exceeded the 0.036 level. Environmental surveillance of microbial pathogens is crucial in order to control and eradicate the effects that increasing anthropogenic impacts have on marine ecosystems and human health.     

Endoparasites in common eiders Somateria mollissima from birds killed by an oil spill in the northern Wadden Sea

Mass mortalities of common eiders Somateria mollissima have been ascribed to high parasite loads. However, the actual role of parasites in mortalities is disputed as in the case of a mass mortality of eiders in the Wadden Sea in the winter of 1999/2000. A critical evaluation of the role of parasites in eider mass mortalities is hampered by (1) a lack of data on actual parasite loads of the birds involved, (2) missing regional data for comparison, and (3) a lack of unbiased samples: investigations are often based on dead beached individuals, which are presumably the more heavily infected birds of a population and thus more likely to die and be washed ashore. Although published data on parasite loads in birds of the winter 1999/2000 mortality are available, no data on background parasitism in eiders from the Wadden Sea exist, making an evaluation of the potential role of parasites in this mortality event difficult. By investigating endoparasites of 102 eiders affected by an oil spill in the northern Wadden Sea in winter 1998/1999, we provide a data set of background parasitism in wintering eiders from the Wadden Sea. We found 13 different parasite taxa with high prevalence values (% infected birds) in the acanthocephalan Profilicollis botulus, the nematode Amidostomum acutum, cestodes and trematodes. In some taxa we observed pronounced differences in prevalence values between juvenile eiders and adults, as well as between adult sexes. The parasite composition shows that bivalves, crabs (Carcinus maenas) and other crustaceans are important sources of infections by being intermediate hosts. This is partly mirrored in the food content of eider stomachs where bivalves and crabs were predominantly found. Intensities of the acanthocephalan P. botulus, suspected of causing eider mortalities, were especially high in juveniles (1112 ± 416 ind per infected host), but lower in adult males (40 ± 7) and adult females (81 ± 18). However, no extraordinary mortality event was observed in the winter of 1998/1999, indicating no or a very weak effect of the parasites on host condition. A comparison with the parasite loads of eiders from the mass mortality in the winter of 1999/2000 shows that parasite numbers were by no means exceptional for birds from the area. Hence, parasites alone are unlikely to have caused this mortality. Regional background parasite loads are important to differentiate between primary and secondary roles of parasites in anomalous mortality events.     

Geographical variation in metazoan parasites of the deep-sea fish Bathypterois mediterraneus Bauchot, 1962 (Osteichthyes: Ipnopidae) from the Western Mediterranean

This study examines the parasite fauna of Bathypterois mediterraneus, the most common fish below 1500 m in Western Mediterranean waters. Samples were obtained during July 2010 from the continental slope of two different areas (off Catalonia and Balearic Islands) in three different bathymetric strata at depths between 1000 and 2200 m. The parasite fauna of B. mediterraneus included a narrow range of species: Steringophorus cf. dorsolineatum, Scolex pleuronectis, Hysterothylacium aduncum, Anisakis sp. larva 3 type II and Sarcotretes sp. Steringophorus cf. dorsolineatum and H. aduncum were the most predominant parasites. H. aduncum showed significant differences in abundance between depths of 2000–2200 m with 1000–1400 m and 1400–2000 m, irrespective of locality, whereas S. cf. dorsolineatum showed significant differences between the two localities at all depths except for 2000–2200 m. We suggest the possible usefulness of these two parasites as geographical indicators for discriminating discrete stocks of B. mediterraneus in Western Mediterranean waters.     

A new subspecies of Ranularia (Mollusca,family cymathdae) from the Kermadec Islands

A new geographic subspecies, Ranularia dunkeri iredalei, is described from beach specimens from Raoul Island in the Kermadec Islands. Ranularia dunkeri dunkeri (Lischke, 1868) is restricted to southern Japan.