Derelict fishing gear in the northwestern Hawaiian Islands: diving surveys and debris removal in 1999 confirm threat to coral reef ecosystems

Marine debris threatens Northwestern Hawaiian Islands' (NWHI) coral reef ecosystems. Debris, a contaminant, entangles and kills endangered Hawaiian monk seals (Monachus schauinslandi), coral, and other wildlife. We describe a novel multi-agency effort using divers to systematically survey and remove derelict fishing gear from two NWHI in 1999. 14 t of derelict fishing gear were removed and debris distribution, density, type and fouling level documented at Lisianski Island and Pearl and Hermes Atoll. Reef debris density ranged from 3.4 to 62.2 items/km². Trawl netting was the most frequent debris type encountered (88%) and represented the greatest debris component recovered by weight (35%), followed by monofilament gillnet (34%), and maritime line (23%). Most debris recovered, 72%, had light or no fouling, suggesting debris may have short oceanic circulation histories. Our study demonstrates that derelict fishing gear poses a persistent threat to the coral reef ecosystems of the Hawaiian Archipelago.     

Marine debris accumulation in the Northwestern Hawaiian Islands: an examination of rates and processes

Large amounts of derelict fishing gear accumulate and cause damage to shallow coral reefs of the Northwestern Hawaiian Islands (NWHI). To facilitate maintenance of reefs cleaned during 1996-2005 removal efforts, we identify likely high-density debris areas by assessing reef characteristics (depth, benthic habitat type, and energy regime) that influence sub-regional debris accumulation. Previously cleaned backreef and lagoonal reefs at two NWHI locations were resurveyed for accumulated debris using two survey methods. Accumulated debris densities and weights were found to be greater in lagoonal reef areas. Sample weight-based debris densities are extrapolated to similar habitats throughout the NWHI using a spatial 'net habitat' dataset created by generalizing IKONOS satellite derivatives for depth and habitat classification. Prediction accuracy for this dataset is tested using historical debris point data. Annual NWHI debris accumulation is estimated to be 52.0 metric tonnes. For planning purposes, individual NWHI atolls/reefs are allotted a proportion of this total.     

Brominated flame retardants and organochlorine contaminants in winter flounder, harp and hooded seals, and North Atlantic right whales from the Northwest Atlantic Ocean

Various brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs) and current-use, non-PBDE BFRs, as well as organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs), were measured in winter flounder, harp and hooded seals, and North Atlantic right whales from the Eastern United States and Canada. The concentrations of PBDEs in winter flounder and right whales were similar in magnitude to the levels of PCBs, which was unlike the pattern observed in seals. In these marine mammals, the levels of PBDEs were orders of magnitude lower than the levels of OCs and PCBs detected. Evidence existed for the accumulation of methoxylated (MeO)-PBDEs of natural origin in seals and right whales. Current-use, non-PBDE BFRs (including hexabromocyclododecane, pentabromoethylbenzene, hexabromobenzene, and pentabromotoluene) were detected in winter flounder and marine mammals. Future research should focus on monitoring PBDEs, current-use, non-PBDE BFRs, and MeO-BDEs of natural origin in marine organisms from Massachusetts and Cape Cod Bays.     

Marine debris from the Oregon Dungeness crab fishery recovered in the Northwestern Hawaiian Islands: identification and oceanic drift paths

Two Dungeness crab trap tags and floats lost off the State of Oregon, USA during the 2006-2007 fishing season were recovered 4years later in the Northwestern Hawaiian Islands (NWHI): on Lisianski Island on July 15, 2010; and on Kure Atoll on December 10, 2010. This is the first documented recovery of marine debris from Oregon fisheries in the NWHI. We simulate the oceanic drift tracks of the derelict fishing gear with the Ocean Surface Current Simulator (OSCURS) model using estimated loss dates in Oregon based on interviews with the crab trap owners and known recovery sites and dates in the NWHI. These data confirm the US Pacific Northwest as a source of marine debris deposited in the NWHI and provide enhanced understanding of the oceanic drift pathways of marine debris in the North Pacific Ocean.     

Contaminants still high in top-level carnivores in the Southern California Bight: levels of DDT and PCBs in resident and transient pinnipeds

Highly industrialized areas, such as the Southern California Bight, often have high levels of contaminants in marine sediments, which can cause chronic exposure to organisms long after their use has ceased. tDDT and tPCB were analyzed in the blubber of 145 stranded pinnipeds that died at local marine mammal centers between 1994 and 2006. Resident species (California sea lion and Pacific harbor seal) had significantly higher concentrations of tDDT and tPCB than the transient species (northern elephant seal). Adult female California sea lions had significantly lower concentrations of tDDT and tPCB than pups, yearlings, and adult males. Concentrations of both tDDT and tPCB in California sea lions significantly declined over time, but did not change in northern elephant seals. Current concentrations of tDDT and tPCB in California sea lions and harbor seals are among the highest values reported worldwide for marine mammals and exceed those reported to cause adverse health effects.     

Organochlorine and butyltin residues in deep-sea organisms collected from the western North Pacific,off-Tohoku,Japan

Organochlorine (OCs) and butyltin (BTs) residues were determined in deep-sea organisms collected from the western North Pacific, off-Tohoku, Japan. Among OCs, concentrations of polychlorinated biphenyls (PCBs) and DDTs (DDTs and its metabolites) were the highest in deep-sea organisms (maximum concentrations of 6700 and 13,000 ng/g lipid wt, respectively). Chlordane compounds (CHLs) were the next most abundant OCs, and hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were the lowest. BTs were also detected at maximum concentrations of 570 ng/g wet wt. Concentrations of PCBs, CHLs and BTs in deep-sea organisms collected from the western North Pacific, off-Tohoku, were generally lower than those in deep-sea and shallow water organisms from Japanese coastal waters. On the other hand, considerable variations in the concentrations of OCs were found among deep-sea organisms analyzed. Several carnivorous fishes such as snubnosed eel, lanternshark and grenadiers accumulated some OCs such as PCBs, DDTs and CHLs at high concentrations of up to a few μg/g levels. In addition, the residue pattern of OCs and BTs in fishes showed a specific trend according to the sampling depth; higher concentrations of PCBs, DDTs and CHLs and lower concentrations of HCHs, HCB and BTs were found in fishes collected from greater depth (1000 m) compared to those from shallower waters. This trend is consistent with the results of our earlier study on mesopelagic myctophid fishes. Results of this study suggest vertical transport of hydrophobic OCs such as PCBs, DDTs and CHLs and its accumulation in benthic deep-sea organisms.     

Organochlorine pesticides in fish from the southern Baltic Sea: levels, bioaccumulation features and temporal trends during the 1995-2006 period

The levels of HCH isomers, HCB and summation DDTs were determined in five species of Baltic fish collected during 1995-2006. Some downward time trends of HCH isomer, pp'-DDE and pp'-DDD concentrations in Baltic fish were observed; in contrast, HCB and DDT concentrations did not exhibit any obvious trend. Concentrations of summation HCHs expressed on a lipid weight basis were very similar in all species studied. In contrast, concentrations of summation DDTs varied in tested species. The most abundant HCH isomer was beta-HCH and among DDT-related compounds, pp'-DDE prevailed. In our investigations the sampling sites were not a crucial factor for organochlorine pesticide concentrations and patterns observed in fish, but the occurrence of several inter-species differences in the bioaccumulation features of OC pesticides were observed. For cod there was a positive correlation between fish size (length) and summation DDT concentration. In herring, sprat and salmon samples, summation DDT concentrations were negatively correlated with fat content.     

Total body burden and tissue distribution of polyfluorinated compounds in harbor seals (Phoca vitulina) from the German Bight

Total body burden and tissue distribution of polyfluorinated compounds (PFCs) were investigated in harbor seals (Phoca vitulina) from the German Bight in 2007. A total number of 18 individual PFCs from the following groups could be quantified in the different tissues: perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonates (PFSAs) and their precursors perfluorinated sulfinates (PFSiAs), perfluorinated sulfonamides, and sulfonamido ethanols. Perfluorooctanesulfonate (PFOS) was the predominant compound in all measured seal tissues (up to 1665 ng g⁻¹ wet weight in liver tissue). The dominant PFCAs were perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA), but their concentrations were much lower compared to PFOS. The mean whole body burden in harbor seals of all detected PFCs was estimated to be 2665 ± 1207 μg absolute. The major amount of the total PFCs burden in the bodies was in blood (38%) and liver (36%), followed by muscle (13%), lung (8%), kidney (2%), blubber (2%), heart (1%), brain (1%), thymus (<0.01%) and thyroid (<0.01%). These data suggest large differences in body burden and accumulation pattern of PFCs in marine mammals.     

Reconstruction of pollution history of organic contaminants in the upper Gulf of Thailand by using sediment cores: first report from Tropical Asia Core (TACO) project

This paper reports the first reconstruction of a pollution history in tropical Asia from sediment cores. Four sediment core samples were collected from an offshore transect in the upper Gulf of Thailand and were analyzed for organic micropollutants. The cores were dated by measurement of (137)Cs and geochronometric molecular markers (linear alkylbenzenes, LABs; and tetrapropylene-type alkylbenzenes, TABs). Polychlorinated biphenyl (PCB) concentrations showed a subsurface maximum in layers corresponding to the 1970s, indicating the effectiveness of regulation of PCBs in Thailand. LAB concentrations increased over time, indicating the increase in input of sewage into the Gulf during the last 30 years. Hopanes, biomarkers of petroleum pollution, also increased over time, indicating that the inputs of automobile-derived hydrocarbons to the coastal zone has been increasing owing to the increased number of cars in Thailand since the 1950s. Polycyclic aromatic hydrocarbons (PAHs) increased in the layers corresponding to the 1950s and 1960s, probably because of the increased inputs of automobile-derived PAHs. PAH concentrations in the upper layers corresponding to the 1970s and later remained constant or increased. The absence of a subsurface maximum of PAHs contrasts with results observed in industrialized countries. This can be explained by the facts that the Thai economy did not depend on coal as an energy source in the 1960s and that economic growth has continued since the 1970s to the present. The deposition flux of PAHs and hopanes showed a dramatic offshore decrease, whereas that of LABs was uniform.     

Hawaiian magma-reservoir processes as inferred from the petrology of gabbro xenoliths in basalt,Kahoolawe Island

Gabbro xenoliths in a tholeiitic lava of Kahoolawe Island, Hawaii, a 1.3–1.4 Ma shield volcano, are 1–3 cm in size and comprised of plagioclase, clinopyroxene, and orthopyroxene. Gabbro textures — while intergranular and in part subophitic-are open due to 28–48 vol.% of vesicular basalt occupying xenolith space. Vesicles in and around the xenoliths are lined or filled with rhyolitic glass (segregation vesicles). The host is evolved tholeiite (MgO 6.1 wt%) with phenocrysts, microphenocrysts, and glomerocrysts of olivine, clinopyroxene, orthopyroxene, and plagioclase, and megacrysts (1 cm) of plagioclase. The Sr-isotope ratio of one xenolith is 0.70489; the host basalt ratio is 0.70460. Xenolith isotope composition, grain resorption, and clinopyroxene (Fs_12.5–15Wo_38–35.5), orthopyroxene (Fs_19.5–24Wo_4.1), and plagioclase (An_68–65Or_0.8–1.2) compositions suggest that these gabbros crystallized from Kahoolawe tholeiitic magma of essentially the same composition as the host basalt, but pre-dating the magma represented by the host. Based on the absence of intergranular Fe–Ti oxide phases from the pl+cpx+opx assemblages, and the open, vuggy textures, we envision crystallization on a reservoir roof at temperatures >1100°C. Entrainment of gabbro assemblages and plagioclase megacrysts from a roof mush/suspension zone occurred during convection associated with replenishment of the magma reservoir. These open-textured gabbro xenoliths are therefore not fragments of preexisting coarse-grained bodies such as sills or segregation veins. Rhyolitic glass in vesicles represents a gas-effervescence filtration process that forced fractionated residual liquids from the groundmass into voids associated with the xenoliths.Sirrine Environmental Consultants, Fremont, CA 94538