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Understanding and managing the response of marine ecosystems to human pressures including climate change requires reliable large-scale and multi-decadal information on the state of key populations. These populations include the pelagic animals that support ecosystem services including carbon export and fisheries. The use of research vessels to collect information using scientific nets and acoustics is being replaced with technologies such as autonomous moorings, gliders, and meta-genetics. Paradoxically, these newer methods sample pelagic populations at ever-smaller spatial scales, and ecological change might go undetected in the time needed to build up large-scale, long time series. These global-scale issues are epitomised by Antarctic krill (Euphausia superba), which is concentrated in rapidly warming areas, exports substantial quantities of carbon and supports an expanding fishery, but opinion is divided on how resilient their stocks are to climatic change. Based on a workshop of 137 krill experts we identify the challenges of observing climate change impacts with shifting sampling methods and suggest three tractable solutions. These are to: improve overlap and calibration of new with traditional methods; improve communication to harmonise, link and scale up the capacity of new but localised sampling programs; and expand opportunities from other research platforms and data sources, including the fishing industry. Contrasting evidence for both change and stability in krill stocks illustrates how the risks of false negative and false positive diagnoses of change are related to the temporal and spatial scale of sampling. Given the uncertainty about how krill are responding to rapid warming we recommend a shift towards a fishery management approach that prioritises monitoring of stock status and can adapt to variability and change.

Understanding and managing the response of marine ecosystems to human pressures including climate change requires reliable large-scale and multi-decadal information on the state of key populations. These populations include the pelagic animals that support ecosystem services including carbon export and fisheries. The use of research vessels to collect information using scientific nets and acoustics is being replaced with technologies such as autonomous moorings, gliders, and meta-genetics. Paradoxically, these newer methods sample pelagic populations at ever-smaller spatial scales, and ecological change might go undetected in the time needed to build up large-scale, long time series. These global-scale issues are epitomised by Antarctic krill (Euphausia superba), which is concentrated in rapidly warming areas, exports substantial quantities of carbon and supports an expanding fishery, but opinion is divided on how resilient their stocks are to climatic change. Based on a workshop of 137 krill experts we identify the challenges of observing climate change impacts with shifting sampling methods and suggest three tractable solutions. These are to: improve overlap and calibration of new with traditional methods; improve communication to harmonise, link and scale up the capacity of new but localised sampling programs; and expand opportunities from other research platforms and data sources, including the fishing industry. Contrasting evidence for both change and stability in krill stocks illustrates how the risks of false negative and false positive diagnoses of change are related to the temporal and spatial scale of sampling. Given the uncertainty about how krill are responding to rapid warming we recommend a shift towards a fishery management approach that prioritises monitoring of stock status and can adapt to variability and change.

Cylindropuntia fulgida var. mamillata (A. Schott ex Engelm.) Backeb. (Cactaceae) (coral or boxing glove cactus) is one of eight invasive species of Cylindropuntia in Australia that have been targeted for biological control. The ‘cholla’ lineage of Dactylopius tomentosus (Lamarck) (Hemiptera: Dactylopiidae) was first released in South Africa in 2008. This lineage is the second of a series of host-specific cochineal insects to be released to control Cylindropuntia species in Australia and was selected to target C. fulgida var. mamillata. Approval to field release this lineage was granted in November 2015 and the cochineal was first released at Leander Station, near Longreach, Queensland in March 2016 and at Booligar Station, near Hebel, Queensland in April 2016. An intensive monitoring program was undertaken at both sites to evaluate the establishment, rate and direction of spread and impact of the D. tomentosus ‘cholla’ lineage on C. fulgida var. mamillata. The cochineal established very well at Leander Station but needed to be re-released at Booligar Station following heavy rain and flooding soon after the first release. Once established, populations of the cochineal at both sites built up very quickly and spread with the prevailing winds, infesting 100% of plants at each of the monitoring sites within 14 months of release. The impact on plants was substantial, with 95% of plants dying at Leander Station within 19 months of the cochineal being released. At Booligar Station, about 98% of plants had died within 18 months of the second cochineal release. Of the plants that were still alive, all had been severely damaged by the cochineal and were showing signs of poor health. These results and observations at other release sites, both in Australia and South Africa, suggest D. tomentosus ‘cholla’ lineage should be an effective agent for the control of C. fulgida var. mamillata.