Spatial variability of metallic and organic contamination of anguilliform fish in New Caledonia

Trace element accumulation in the muscles of reef fish collected from southern new Caledonian lagoon: Risk assessment for consumers and grouper Plectropomus leopardus as a possible bioindicator of mining contamination

Flesh of 141 fish specimens collected along the southern coast of New Caledonia, close to the mining industry Prony Resources New Caledonia, were analyzed for 10 elements (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni and Zn). The leopard coral grouper Plectopomus leopardus revealed significant spatial variations for Cr, Fe, Mn and Zn and size-dependent accumulation of Hg. Sanitary risk assessment suggests that Hg and Me-Hg could potentially be a concern for heavy fish consumers. A previous study in New Caledonia had demonstrated the capacity of P. leopardus to differentially accumulate Ag, Cd, Cu, Hg and Zn and as such its potential as bioindicator specie to monitor contamination status in urban areas (Metian et al., 2013). Our results demonstrate that this specie can also to be used as a bioindicator to monitor the contamination status of Cr, Fe and Mn in New Caledonian lagoon in relation to mining activities.

Trace element contamination of soil and dust by a New Caledonian ferronickel smelter: Dispersal, enrichment, and human health risk

Metallurgical industries remain a considerable source of trace element contamination and potential human health risk. Determination of sources is a key challenge. With respect to the South Pacific's largest and longest operating metallurgic smelter in Nouméa, New Caledonia, determining the environmental impact and subsequent human health risk associated with local ferronickel smelting is complicated by natural geological enrichment of Ni and Cr. This study applies a multi-method and multi-matrix approach to disentangle smelter emissions from geogenic sources and model the consequent health risk from industrial activity. Dust wipes (n = 108), roadside soil (n = 91), garden soil (n = 15) and household vacuum dust (n = 39) were assessed to explore geospatial trace element (As, Cr, Cu, Fe, Mn, Ni, Pb, S, V and Zn) variations across outdoor and indoor environments. Enrichment factors (EF) identified elevated levels of smelter-related trace elements: S (EF = 7), Ni (EF = 6) and Cr (EF = 4), as well as Zn (EF = 4). Smelter-related elements in soil and dust deposits were negatively correlated with distance from the facility. Similarity of Pb isotopic compositions between dust wipes, surface soil and vacuum dust indicated that potentially toxic trace elements are being tracked into homes. Non-carcinogenic health risk modelling (Hazard Index, HI) based on 15 spatial nodes across Nouméa revealed widespread exceedance of tolerable risk for children (0-2 years) for Ni (HI 1.3-15.8) and Mn (HI 0.6-1.8). Risk was greatest near the smelter and to the north-west, in the direction of prevailing wind. Given the elevated cancer risk documented in New Caledonia, disentanglement of environmental from industrial sources warrants further attention to ensure community health protection. Our analysis illustrates how the confounding effects from complex environmental factors can be distilled to improve the accuracy of point source apportionment to direct future mitigation strategies.

Knowledge gaps in ecotoxicology studies of marine environments in Pacific Island Countries and Territories - A systematic review

The Pacific Island Countries and Territories (PICTs) are heavily dependent on the marine resources for food security, employment, government revenue and economic development, hence the concern about the potential exposure of these resources to pollutants. The main goal of this review was to identify ecotoxicology studies published that were done in PICTs. Four major gaps were identified: i) a quantitative gap, with low number of studies published on the PICTs; ii) a geographic gap, where ecotoxicology studies have unevenly covered the different PICTs; iii) a temporal gap, as no biological effect monitoring study has so far been published for the PICTs; and, iv) a pollutants gap, as all of the PICTs studies focused mainly on environmental monitoring studying on average two types of pollutants (heavy metals and pesticides) per PICT only. We suggest, therefore, the potential risk to the marine environment to be estimated by assessing the fate of pollutants via chemical and biological effect monitoring.

New species and new records of camallanid nematodes (Nematoda, Camallanidae) from marine fishes and sea snakes in New Caledonia

Recent examinations of camallanid nematodes (Camallanidae) from marine fishes off New Caledonia, collected in the years 2003–2011, revealed the presence of the following five new species of Procamallanus Baylis, 1923, all belonging to the subgenus Spirocamallanus Olsen, 1952: Procamallanus (Spirocamallanus) dispar n. sp. from the common ponyfish Leiognathus equulus (type host) and the striped ponyfish Aurigequula fasciata (both Leiognathidae, Perciformes); Procamallanus (Spirocamallanus) bothi n. sp. from the leopard flounder Bothus pantherinus (Bothidae, Pleuronectiformes); Procamallanus (Spirocamallanus) hexophtalmatis n. sp. from the speckled sandperch Parapercis hexophtalma (Pinguipedidae, Perciformes); Procamallanus (Spirocamallanus) synodi n. sp. from the sand lizardfish Synodus dermatogenys (Synodontidae, Aulopiformes); and Procamallanus (Spirocamallanus) thalassomatis n. sp. from the yellow-brown wrasse Thalassoma lutescens (Labridae, Perciformes). These are described based on light and scanning electron microscopical (SEM) studies. An additional three congeneric nematodes unidentifiable to species are reported from perciform fishes and a shark: Procamallanus (Spirocamallanus) sp. 3 of Moravec et al., 2006, Procamallanus (Spirocamallanus) sp. 1, and Procamallanus (Spirocamallanus) sp. 2. Ten fish species are recorded as new hosts for Camallanus carangis Olsen, 1954. Two camallanids, Procamallanus (Spirocamallanus) sp. 3 (subgravid female) and Camallanus carangis (fourth-stage larva) were also found in the digestive tract of the New Caledonian sea krait Laticauda saintgironsi, serving apparently as postcyclic and paratenic hosts, respectively, for these fish nematodes.

Does trophic level drive organic and metallic contamination in coral reef organisms?

Metallic and organic pollutants constitute a serious threat for coral reef ecosystems, potentially affecting a great number of species interacting within complex trophodynamic processes. Pesticides, PCBs and trace elements were measured on coral reef communities of three Pacific islands (Moorea, Wallis and New Caledonia) in relation with δ¹⁵N values, a proxy of trophic level. Several potential sources of organic matter, benthic invertebrates and fish belonging to various trophic strategies were sampled at each island. Wallis and New Caledonia displayed, respectively, the highest concentrations of pesticides and trace elements. In the three islands, most trace element concentrations (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and V) decreased when δ¹⁵N was rising (i.e. bioreduction), whereas Hg and Se biomagnified with increasing δ¹⁵N values. Only few trace elements in some islands did not show any significant trend in relation with δ¹⁵N (i.e., Ag in New Caledonia, Zn in Wallis and As plus Zn in Moorea). PCBs concentrations showed a significant bioreduction in New Caledonia and in Moorea, but a significant biomagnification in Wallis. Aldrin and heptachlor were the only pesticides to show a similar significant bioreduction in the three islands. Other pesticides, such as chlordecone, diazinon, endosulfan I and II, heptachlor-epoxide A and B, lindane and pp'-DDE displayed contrasted patterns (e.g. chlordecone significantly biomagnified in New Caledonia, significantly bioreduced in Wallis and did not displayed any significant trend in Moorea). Finally, for unclear reasons, Moorea displayed only negative significant correlations between δ¹⁵N and all pesticides (except pp'-DDT). Our results highlight that trophic level, here assessed through δ¹⁵N values, is a good predictor of metallic trace elements biomagnification or bioreduction in coral reef organisms. However, at large spatial scale, trophic level relevance to predict pesticides and PCBs biomagnification or bioreduction should be considered with caution and studied in close relation with local characteristics.

Differential uses of coral reef habitats by a poorly-known cryptic fish predator

This study used otolith microchemistry to evaluate whether the moray eel Gymnothorax chilospilus uses different habitats throughout its life (mainly juvenile and adult phases). Of the most informative trace elements within otoliths (the twelve isotopes ²³ Na, ²⁵ Mg, ⁴³ Ca, ⁵⁵ Mn, ⁵⁹ Co, ⁶⁰ Ni, ⁶³ Cu, ⁶⁶ Zn, ⁸⁶ Sr, ¹¹¹ Cd, ¹³⁸ Ba and ²⁰⁸ Pb) only three ratios of Ca (Na:Ca, Sr:Ca and Ba:Ca) were informative and therefore used in a multivariate regression-tree analysis. Using a multivariate partitioning, three main phases were described from profiles, including the larval life phase (leptocephali), the intermediate phase (longest section between the larval life phase and the terminal phase) and the terminal phase (final section i.e., the most recent months preceding the death of fish). According to concentrations of the three ratios to Ca, G. chilospilus can be separated into three groups during their larval life stage (very different in Sr and Na), four groups during the intermediate phase (few differences in Sr and Na) and three groups during the terminal phase (differences in Sr), illustrating that G. chilospilus inhabit different habitats during these three phases. Our results showed that the leptocephali encountered different oceanic water masses with fluctuating Sr:Ca ratios during the early larval phase. During the intermediate phase (main part of their life-span), they lived in lagoonal waters such as fringing reefs or reef flats of lagoonal islets, characterized by a lower Sr:Ca ratio. During the latter part of their life, approximately one third of G. chilospilus encountered more oceanic waters close to or at barrier reefs, suggesting possible movements of these fish along a coast-to-ocean gradient.

Three new species of Cucullanus (Nematoda: Cucullanidae) from marine fishes off New Caledonia, with a key to species of Cucullanus from Anguilliformes

Based on light and scanning electron microscopical studies of nematode specimens from the digestive tract of some rarely collected anguilliform and perciform fishes off New Caledonia, three new species of Cucullanus Müller, 1777 (Cucullanidae) are described: C. austropacificus n. sp. from the longfin African conger Conger cinereus (Congridae), C. gymnothoracis n. sp. from the lipspot moray Gymnothorax chilospilus (Muraenidae), and C. incognitus n. sp. from the seabream Dentex fourmanoiri (Sparidae). Cucullanus austropacificus n. sp. is characterized by the presence of cervical alae, ventral sucker, alate spicules 1.30–1.65 mm long, conspicuous outgrowths of the anterior and posterior cloacal lips and by elongate-oval eggs measuring 89–108 × 48–57 μm; C. gymnothoracis n. sp. is similar to the foregoing species, but differs from it in the absence of cervical alae and the posterior cloacal outgrowth, in the shape and size of the anterior cloacal outgrowth and somewhat shorter spicules 1.12 mm long; C. incognitus n. sp. (based on female morphology) differs from other congeneric species parasitic in the Sparidae mainly in possessing cervical alae, the postequatorial vulva, phasmids situated at the mid-length of the tail and in the size of the eggs (75–84 × 45–66 μm). A key to species of Cucullanus parasitizing anguilliform fishes is provided.

Contamination of marine fauna by chlordecone in Guadeloupe: evidence of a seaward decreasing gradient

Chlordecone is an organochlorine pesticide, used in the Lesser Antilles from 1972 to 1993 to fight against a banana weevil. That molecule is very persistent in the natural environment and ends up in the sea with runoff waters. The objective of the present study is to evaluate the level of contamination in several trophic groups of marine animals according to their distance from the source of pollution. Samples of suspended matter, macroalgae, herbivorous fishes, detrivorous crustaceans, zooplanktivorous fishes, first- and second-order of carnivorous fishes, and piscivorous fishes have been collected in two sites, located downstream the contaminated sites (Goyave and Petit-Bourg), in three marine habitats (coastal mangroves, seagrass beds located 1.5 km from the shoreline, and coral reefs at 3 km offshore). Animals collected in mangroves were the most contaminated (mean concentrations 193 μg kg^-1 in Goyave and 213 μg kg^-1 in Petit-Bourg). Samples from seagrass beds presented intermediate concentrations of chlordecone (85 μg kg^-1 in Goyave and 107 μg kg^-1 in Petit-Bourg). Finally, samples from coral reefs were the less contaminated (71 μg kg^-1 in Goyave and 74 μg kg^-1 in Petit-Bourg). Reef samples, collected 3 km offshore, were two to three times less contaminated than those collected in mangroves.

Tracking trace elements into complex coral reef trophic networks

The integration, accumulation and transfer of trace elements across the main tropic levels of many food webs are poorly documented. This is notably the case for the complex trophic webs of coral reef ecosystems. Our results show that in the south-west lagoon of New Caledonia both abiotic (i.e. sediments) and biotic (i.e. primary producers, consumers and predators) compartments are contaminated by trace elements. However, our analyses revealed different contamination patterns from the sources of organic matter to the predators. The trophic levels involved in the sedimentary benthic food web (S-BFW, based on the sedimentary organic matter) and to a lesser extent in the reef benthic food web (R-BFW, based on algal turf) were mainly contaminated by trace elements that originate from mining activities like Ni and associated trace elements (Co, Cr, Fe, and Mn). Trace elements linked to agro-industrial (As, Hg, and Zn) and urban (Ag, Cd, Cu, Pb, Se, and V) activities were also integrated into the S-BFW, but preferentially into the R-BFW, and to a lesser extent into the detrital benthic food web (D-BFW, supplied by sea-grass plants). Most of the trace elements were biodiminished with increasing trophic levels along food webs. However, a marked biomagnification was observed for Hg, and suspected for Se and Zn. These results provide important baseline information to better interpret trace element contamination in the different organisms and trophic levels in a highly diversified coral reef lagoon.

Occurrence of Anisakis (Nematoda: Anisakidae) larvae in unusual hosts in Southern hemisphere

Nematodes belonging to the genus Anisakis are important parasites due to their abundance in seafood and health impacts on humans. In the present study Anisakis larvae were found in a number of uncommon hosts including the Grey petrel, Procellaria cinerea, the Little penguin, Eudyptula minor, Blue-lipped sea krait, Laticauda laticaudata and Spinner shark, Carcharhinus brevipinna. Morphological examination showed nematodes in these animals are Anisakis larval type I. Genetic characterisation suggested that the larva from one Grey petrel was Anisakis berlandi, whereas the other larvae from the second Grey petrel and from the little penguin were Anisakis pegreffii. A number of larvae found in Blue-lipped sea krait and Spinner shark were identified as Anisakis typica. This is the first report of infective stage of Anisakis larvae parasitising hosts other than teleost fish. Understanding of the extent of infection and the pathogenicity of anisakid nematodes in hosts found in the present study is important in the conservation studies and management plans of these hosts.