SignificanceWe conducted a systematic, high-resolution analysis of bottom trawl fishing footprints for 24 regions on continental shelves and slopes of five continents and New Zealand. The proportion of seabed trawled varied >200-fold among regions (from 0.4 to 80.7% of area to a depth of 1,000 m). Within 18 regions, more than two-thirds of seabed area remained untrawled during study periods of 2–6 years. Relationships between metrics of total trawling activity and footprint were strong and positive, providing a method to estimate trawling footprints for regions where high-resolution data are not available. Trawling footprints were generally smaller in regions where fisheries met targets for exploitation rates, implying collateral environmental benefits of effective fisheries management.

Vaccination is a medical procedure, and the decision to vaccinate should be based on a risk-based assessment for each cat and each vaccine.

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Results suggested that feral and pet cats had similar baseline health status, as reflected by results of hematologic and serum biochemical testing and similar prevalences of infection with Cryptosporidium spp, Giardia spp, and T. cati. Feral cats did have higher seroprevalences of antibodies against B. henselae and T. gondii than did pet cats, but this likely was related to greater exposure to vectors of these organisms.

White sharks, Carcharodon carcharias, are often described as elusive, with little information available due to the logistical difficulties of studying large marine predators that make long-distance migrations across ocean basins. Increased understanding of aggregation patterns, combined with recent advances in technology have, however,

The effect of community structure on the functioning of the ecosystem is an important issue in ecology due to continuing global species loss. The influence of infaunal community structure on the functioning of marine systems is proposed here to act primarily through bioturbation of the sediment. Nutrient concentration in the water column, generated by release from the sediment, was used as a measure of ecosystem functioning. In situ and laboratory experiments showed a significant difference in nutrient concentrations with different species treatments. Bioturbation profiles showing the incorporation of tracer particles also differed between communities with different dominant species. The behavioural differences between infaunal species, generating different modes and rates of bioturbation, are therefore proposed to influence nutrient release. The presence and quantity of bioturbating infauna also influenced the amount of sediment suspended in the water column. The increase in surface area available for microbial activity may generate an increase in nutrient cycling. Abiotic influences on sediment structure, such as flow, may have a similar effect on nutrient concentration. Annular flumes used in both laboratory and in situ experiments to generate flow conditions produced a significant increase in ammonia (NH 4 -N) production in macrofaunal treatments. Flow may influence the behaviour of macrofaunal species, causing changes in NH 4 -N production through modifying bioturbation of the sediment.

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Increased sedimentation from changes in land use in coastal areas is a potentially important impact of human urbanisation. The potential impact of sedimentation on benthic infauna was quantitatively investigated in the Okura estuary, which is at the northern fringes of urban development in Auckland, New Zealand. A structured mensurative sampling programme, measuring benthic infauna and various environmental variables, is described. Of the variance in macrofaunal assemblages from 15 sites throughout the Okura estuary on 6 sampling occasions, 70% was explained by environmental variables. Proportions of ambient sediment grain-sizes, depositional categories from previous models, the amount and characteristics of trapped sediments, organic content, changes in bed height and distance from the mouth of the estuary were all useful in explaining variation in macrofaunal assemblages. Levels of sedimentation recorded in this study were sub-catastrophic (< 3 cm of deposition d -1 ), corresponding to natural fluctuations in sedimentation. Bivalves generally had a negative relationship with sedimentation, while certain burrowing crabs and polychaetes were more abundant in high-deposition environments. The total amount and the grain-size characteristics of trapped sediments explained a significant proportion of the variation in soft-sediment assemblages, over and above the variation explained by ambient sediment variables. Thus, sedimentation appears to be an important structuring force in these intertidal estuarine macrobenthic assemblages.KEY WORDS: New Zealand · Intertidal · Soft sediment · Sedimentation · Estuarine · Impact · MacrofaunaResale or republication not permitted without written consent of the publisher