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Harmful algal blooms (HABs) have wide-ranging environmental impacts, including on aquatic species of social and commercial importance. In New Zealand (NZ), strategic growth of the aquaculture industry could be adversely affected by the occurrence of HABs. This review examines HAB species which are known to bloom both globally and in NZ and their effects on commercially important shellfish and fish species. Blooms of Karenia spp. have frequently been associated with mortalities of both fish and shellfish in NZ and the sub-lethal effects of other genera, notably Alexandrium spp., on shellfish (which includes paralysis, a lack of byssus production, and reduced growth) are also of concern. Climate change and anthropogenic impacts may alter HAB population structure and dynamics, as well as the physiological responses of fish and shellfish, potentially further compromising aquatic species. Those HAB species which have been detected in NZ and have the potential to bloom and harm marine life in the future are also discussed. The use of environmental DNA (eDNA) and relevant bioassays are practical tools which enable early detection of novel, problem HAB species and rapid toxin/HAB screening, and new data from HAB monitoring of aquaculture production sites using eDNA are presented. As aquaculture grows to supply a sizable proportion of the world’s protein, the effects of HABs in reducing productivity is of increasing significance. Research into the multiple stressor effects of climate change and HABs on cultured species and using local, recent, HAB strains is needed to accurately assess effects and inform stock management strategies.

Seagrass systems of the Western Pacific region are biodiverse habitats, providing vital services to ecosystems and humans over a vast geographic range. SeagrassNet is a worldwide monitoring program that collects data on seagrass habitats, including the ten locations across the Western Pacific reported here where change at various scales was rapidly detected. Three sites remote from human influence were stable. Seagrasses declined largely due to increased nutrient loading (4 sites) and increased sedimentation (3 sites), the two most common stressors of seagrass worldwide. Two sites experienced near-total loss from of excess sedimentation, followed by partial recovery once sedimentation was reduced. Species shifts were observed at every site with recovering sites colonized by pioneer species. Regulation of watersheds is essential if marine protected areas are to preserve seagrass meadows. Seagrasses in the Western Pacific experience stress due to human impacts despite the vastness of the ocean area and low development pressures.

This study examined the potential use of macroalgae epiphytic on mangrove aerial roots as indicators of estuarine contamination. The distribution and abundance of macroalgae was investigated in four estuaries in the vicinity of Sydney, Australia, and compared to water and sediment metal concentrations, nutrient concentrations and physicochemical parameters over four seasonal surveys. Macroalgal diversity and distribution appeared to be highly influenced by the ambient contaminant concentrations, while biomass appeared to be linked with nutrient concentrations. The distribution of the Rhodophyta species, Catenella nipae Zanardini significantly decreased as metal concentrations increased among the estuaries during all seasonal surveys. This species showed strong potential for use as a bioindicator of estuarine contamination.

AbstractWarming of freshwaters as a result of climate change is expected to have complex interactions with the toxicity of contaminants to aquatic organisms. The present study evaluated the effects of temperature on the acute toxicity of endosulfan, chlorpyrifos, and phenol to 3 warm water species of fish—silver perch, rainbowfish, and western carp gudgeon—and 1 cold water species, rainbow trout. Endosulfan was more toxic to silver perch at 30 °C and 35 °C than at 15 °C, 20 °C and 25 °C during short exposures of 24 h, but at 96 h, temperature had no effect on toxicity. Toxicity to rainbow trout increased with increasing temperature, whereas warm water species exhibited maximum toxicity at around 30 °C, decreasing again toward 35 °C. Chlorpyrifos became more toxic to all species with increasing temperature. Phenol toxicity to all species decreased at low to intermediate temperatures; but as temperatures increased further toward the upper thermal limit, phenol became more toxic. Increasing toxicity in the upper thermal range of cold water species may contribute to upstream range contraction in rivers with high toxicant loads. In contrast, warm water species may not exhibit a range shift within rivers as a result of interactions between temperature and toxicity. Catchment management to offset global warming at local scales may present opportunities to mitigate increased toxicity of contaminants to fish. Environ Toxicol Chem 2015;34:1809–1817. © 2015 SETAC

The extent of seabed licensed for offshore renewables is being expanded with the global requirement to reduce carbon emissions. The opportunity for Nature-based Solutions for restoration, conservation, mariculture, infrastructure protection, and carbon sequestration initiatives are being explored internationally. Co-location of marine renewable or structures with conservation initiatives offers the opportunity to support populations of threatened species and contribute to wider ecosystem services and benefits. Building on experience from a North Sea project, we explore the feasibility to co-locate bivalve species at offshore wind farms. We present a three-step approach to identify offshore wind farm sites with the potential to co-locate with compatible species within a marine licensed area, based on environmental and physical conditions and biological tolerances. These steps are, (1) information collection and data synthesis, (2) data analysis through site suitability and species compatibility assessments, and (3) numerical modelling approaches to test the feasibility of pilot studies and scale-up planned operations. This approach supports feasibility assessment by identification of sites where Nature-based Solution project success is more likely or certain, thereby reducing project costs and risk of failure. An example case study is provided using Gunfleet Sands offshore wind farm (southeast England) and the restoration and conservation of the commercially valuable European Flat Oyster (Ostrea edulis).

Climate change is predicted to lead to more extreme weather events, including changes to storm frequency, intensity and location. Yet the ecological responses to storms are incompletely understood for sandy shorelines, the globe’s longest land-ocean interface. Here we document how storms of different magnitude impacted the invertebrate assemblages on a tidal flat in Brazil. We specifically tested the relationships between wave energy and spatial heterogeneity, both for habitat properties (habitat heterogeneity) and fauna (β-diversity), predicting that larger storms redistribute sediments and hence lead to spatially less variable faunal assemblages. The sediment matrix tended to become less heterogeneous across the flat after high-energy wave events, whereas β-diversity increased after storms. This higher β-diversity was primarily driven by species losses. Significantly fewer species at a significantly lower density occurred within days to weeks after storms. Negative density and biomass responses to storm events were most prominent in crustaceans. Invertebrate assemblages appeared to recover within a short time (weeks to months) after storms, highlighting that most species typical of sedimentary shorelines are, to some degree, resilient to short-term changes in wave energy. Given that storm frequency and intensity are predicted to change in the coming decades, identifying properties that determine resilience and recovery of ecosystems constitute a research priority for sedimentary shorelines and beyond.

This article discusses two key issues: firstly, the demise of reefs in the Gulf which is happening probably more rapidly than elsewhere; and secondly, the reasons why this remains such an intractable problem. Most reasons for this decline are scientifically well understood, though clearly not by the region's managers. Several factors may cause people to ignore the problem, even though habitat loss is vastly costly to the region. About 70% of the Gulf's reefs have essentially disappeared in a few decades, and although scientific indicators confirm that this is happening, it is commonly discounted as even being a possibility. Management of human interactions with the Gulf's marine systems remains very inadequate, to the detriment of the Gulf's marine systems and its people. It is clear that this not a scientific issue any longer but rather it is a political problem and failure.

The Arctic is experiencing rapid warming, and resultant sea ice losses represent a serious threat to ice-associated species in the region. This study explored the distribution and abundance of the 3 Arctic resident whale species: narwhals, bowhead and white whales, in the marginal ice zone and into the sea ice north of the Svalbard Archipelago. Line-transect surveys were conducted using a combination of helicopter-based and ship-based efforts in August 2015. Twenty-six sightings, involving 27 bowhead whales and 58 narwhals, occurred along the helicopter transects, while no whales were recorded along ship transects. No white whales were observed during these surveys. After correcting for surface availability, distance sampling produced abundance estimates of 343 (CV = 0.488) bowhead whales and 837 (CV = 0.501) narwhals within the 52919 km2 study area. Bowhead whales were predominantly seen close to the ice-edge, whereas narwhals were located deeper into the ice. To contextualize these results within the broader Svalbard cetacean community, all whale sightings from the Norwegian Polar Instituteís Svalbard Marine Mammal Sighting Data Base, from the period of the survey, were mapped to compare general distributions. These opportunistic sightings included numerous cetacean species, especially seasonally occurring ones. However, white whales dominated in terms of the numbers of individuals reported. Our results suggest little spatial overlap between seasonally occurring whales and the 3 Arctic resident whales. Bowhead whales and narwhals were tightly associated with sea ice, and white whales were tightly coastal. In contrast, the seasonally occurring species were found over the shelf and along its edges.