Explore the vast range of titles available.

Growth is a fundamental biological process, driven by a multitude of intrinsic (within-individual) and extrinsic (environmental) factors, that underpins individual fitness and population demographics. Focusing on the comprehensive information stored in aquatic and terrestrial organism hard parts, we develop a series of increasingly complex hierarchical models to explore spatial and temporal sources of growth variation, ranging in resolution from within individuals to across a species. We apply this modeling framework to an extensive data set of otolith increment measurements from tiger flathead ( Platycephalus richardsoni ), a demersal commercially exploited fish that inhabits the warming waters of southeast Australia. We recreated growth histories (biochronology) up to four decades in length from seven fishing areas spanning this species' range. The dominant pattern in annual growth was an age-dependent, allometric decline that varied among individuals, sexes, fishing areas, years, and cohorts. We found evidence for among-area differences in growth-rate selectivity, whereby younger fish at capture were generally faster growers. Temporal growth variation was partitioned into two main sources: extrinsic year to year annual fluctuations in environmental conditions and persistent cohort-specific growth differences, reflecting density dependence and/or juvenile experience. Despite low levels of among-individual growth synchrony within areas, we detected a regionally coherent signal of increasing average growth rate through time, a trend related to oceanic warming. At the southerly (poleward) range limit, growth was only weakly related to temperature, but farther north in warmer waters this relationship strengthened until closer to the species' equatorward range limit, growth declined with increasing temperatures. We partitioned these species-wide and area-specific phenotypic responses into within- and among-individual components using a reaction norm approach. Individual tiger flathead likely possess sufficient growth plasticity to successfully adapt to warming waters across much of their range, but increased future warming in the north will continue to depress growth, affecting individual fitness and even population persistence. Our modeling framework is directly applicable to other long-term, individual-based, data sets such as those derived from tree rings, corals, and tag-recapture studies, and provides an unprecedented level of resolution into the drivers of growth variation and the ecological and evolutionary implications of environmental and climatic change.

Fishing and climate change are profoundly impacting marine biota through unnatural selection and exposure to potentially stressful environmental conditions. Their effects, however, are often considered in isolation, and then only at the population level, despite there being great potential for synergistic selection on the individual. We explored how fishing and climate variability interact to affect an important driver of fishery productivity and population dynamics: individual growth rate. We projected that average growth rate would increase as waters warm, a harvest‐induced release from density dependence would promote adult growth, and that fishing would increase the sensitivity of somatic growth to temperature. We measured growth increments from the otoliths of 400 purple wrasse (Notolabrius funicola), a site‐attached temperate marine reef fish inhabiting an ocean warming hotspot. These were used to generate nearly two decades of annually resolved growth estimates from three populations spanning a period before and after the onset of commercial fishing. We used hierarchical models to partition variation in growth within and between individuals and populations, and attribute it to intrinsic (age, individual‐specific) and extrinsic (local and regional climate, fishing) drivers. At the population scale, we detected predictable additive increases in average growth rate associated with warming and a release from density dependence. A fishing–warming synergy only became apparent at the individual scale where harvest resulted in the 50% reduction of thermal growth reaction norm diversity. This phenotypic change was primarily caused by the loss of larger individuals that showed a strong positive response to temperature change after the onset of size‐selective harvesting. We speculate that the dramatic loss of individual‐level biocomplexity is caused by either inadvertent fisheries selectivity based on behaviour, or the disruption of social hierarchies resulting from the selective harvesting of large, dominant and resource‐rich individuals. Whatever the cause, the removal of individuals that display a positive growth response to temperature could substantially reduce species’ capacity to adapt to climate change at temperatures well below those previously thought stressful. The authors demonstrate that harvesting can affect the sensitivity of temperate reef fish to warming via changes in the expression of individual thermal reaction norms. Whilst fishing relaxed density‐dependent constraints on growth, it halved the phenotypic diversity present in populations through either inadvertent selection or the disruption of social hierarchies.

The oceanographic consequences of climate change are increasingly well documented, but the biological impacts of this change on marine species much less so, in large part because of few long-term data sets. Using otolith analysis, we reconstructed historical changes in annual growth rates for the juveniles of eight long-lived fish species in the southwest Pacific, from as early as 1861. Six of the eight species show significant changes in growth rates during the last century, with the pattern differing systematically with depth. Increasing temperatures near the ocean surface correlate with increasing growth rates by species found in depths <250 m, whereas growth rates of deep-water (>1,000 m) species have declined substantially during the last century, which correlates with evidence of long-term cooling at these depths. The observations suggest that global climate change has enhanced some elements of productivity of the shallow-water stocks but also has reduced the productivity, and possibly the resilience, of the already slow-growing deep-water species.

Historical evidence provides a valuable context for models that predict the biological impacts of climate change, but such long-term data sets are sparse for aquatic systems. This Review outlines the potential of aquatic biochronologies — generated from the hard parts of fish, molluscs and corals — to provide long-term ecological insights into marine and freshwater environments. Historical evidence provides essential context for models predicting the biological impacts of climate change. Such long-term data sets are relatively common for terrestrial taxa and environments, but sparse for aquatic systems. Aquatic biochronologies — generated from information recorded in the hard parts of fish, molluscs and corals that are archived in their millions worldwide — can provide valuable long-term ecological insights into marine and freshwater environments. These resources are, however, at present under-utilized in the measurement and prediction of ecological responses to climate change, despite their potential to provide unprecedented levels of spatial and temporal detail in aquatic environments.

Port Phillip Bay (PPB) is a large (1,930 km²), temperate embayment in southern Victoria, Australia. Extensive bay-wide surveys of PPB have occurred since 1840. In 1995/1996 the Commonwealth Scientific and Industrial Research Organization (CSIRO) Centre for Research on Introduced Marine Pests (CRIMP) undertook an intensive evaluation of the region with the aims of developing a comprehensive species list of native and introduced biota and contrasting previous bay-wide assessments with a current field survey in order to detect new incursions and discern alterations to native communities. Two methods were used to meet these aims: a re-evaluation of regional museum collections and published research in PPB to identify and determine the timing of introductions; and field surveys for benthic (infauna, epifauna and encrusting) organisms between September 1995 to March 1996. One hundred and sixty introduced (99) and cryptogenic (61) species were identified representing over 13% of the recorded species of PPB. As expected, the majority of these are concentrated around the shipping ports of Geelong and Melbourne. Invasions within PPB appear to be increasing, possibly due to an increase in modern shipping traffic and an increase in aquaculture (historically associated with incidental introductions); however the records of extensive biological surveys suggest that this may, in part, be an artefact of sampling effort. In contrast to Northern Hemisphere studies, PPB (and Southern Hemisphere introductions in general) have significantly different suites of successfully invading taxa. PPB is presented as one of the most invaded marine ecosystems in the Southern Hemisphere.

The effects of invasive pathogens on wild fish and fish communities generally are not well documented. We compiled information on the impacts of mass mortality events due to Cyprinid Herpesvirus-3 (CyHV-3), otherwise known as Koi Herpesvirus, on wild North American populations of the invasive cyprinid, Cyprinus carpio (common carp), based on our personal experiences, discussions with North American fish ecologists and virologists, a detailed survey of technical and popular publications and a web search. We found evidence of 17 mass die-offs of carp due to CyHV-3 in North America since 2004, for 7 of which we were able to obtain information about carp before and after the events. For 6 of the events, effects of the die-offs on carp population indices appeared to be slight. Carp size-frequency distributions before and after the well-documented 2007/08 event in Ontario were also not conspicuously different. The exceptional event was at Blue Springs Lake, Missouri, in 2012, at which we estimate 65% of the carp present died as a result of CyHV-3 infections and carp abundance continues to decline. Why Blue Springs Lake differs from other events in North America is not clear. Overall, carp die-offs due to CyHV-3 in North America (1) confirm laboratory studies that only common carp are affected, (2) are of brief duration (3–6 weeks), (3) are not repeated in subsequent years and (4) cause much lower mortality (with the exception of Blue Springs Lake) than previously reported for carp in aquaculture facilities or in the laboratory. In terms of both wild carp and their effects on aquatic communities, the short and long-term effects of most die-offs appear to be slight. These features could have implications for the effectiveness of the proposed use of CyHV-3 to reduce feral carp populations in Australia.

Several factors, including: (1) on-going difficulties of cost-effectively managing invasive species; (2) recent successes in using recombinant genetics to suppress mosquito populations; and, (3) developments in gene-drive technology, have re-invigorated interest in using genetic biotechnology to manage the impacts of invasive species. However, the extent to which there is ‘social license’ to develop and use these technologies has not been widely canvassed. We surveyed stakeholders involved directly and indirectly in managing Sea Lamprey (Petromyzon marinus) in the upper North American Great Lakes and a key community group of resource users—recreational fishers—to assess their support and concerns about researching, developing, and potentially implementing recombinant methods that an expert group assessed as likely to be effective in managing Sea Lamprey in the Great Lakes. Both groups overwhelmingly supported initiating R&D and, if risks were deemed very low, undertaking steps towards implementation. The key concern expressed by both groups was the risk of impacts to non-target taxa, including valued native populations of Sea Lamprey outside of the Great Lakes. Few respondents expressed opposition based on ethical or moral grounds, which contrasts with previous surveys on the use of recombinant technology in general. The broad support for R&D into recombinant approaches is likely to reflect trust in the nominated implementing agency (the Great Lakes Fishery Commission), its history of extensive consultation prior to undertaking management actions, and the hope that genetic biocontrol could “solve” the Sea Lamprey problem rather than simply managing it.

Sometime between 2010 and 2012, Nile Tilapia (Oreochromis niloticus) invaded the remote Lake Kutubu, in the Southern Highlands of Papua New Guinea, apparently as a result of flooded aquaculture ponds. The subsequent burgeoning population of Tilapia has had apparent impacts on the RAMSAR-listed lakes’ ecology, but paradoxically may be benefiting endemic fish and crustaceans in the lake that have been under severe threat of extinction due to sustenance overfishing. Here, we explore options for eradicating or adaptively managing the invasive Tilapia population, and conclude that it is logistically and socially feasible to use low-risk genetic (chromosomal) technology to establish a non-self-sustaining population in the lake as an alternative protein source for local communities that causes minimal environmental damage while reducing exploitation rates on endemic taxa that have already driven at least three to apparent extinction.

Genetic options for the control of invasive fishes were recently reviewed and synthesized at a 2010 international symposium, held in Minneapolis/St. Paul, MN, USA. The only option currently available “off-the-shelf” is triploidy, which can be used to produce sterile males for a release program analogous to those widely and successfully used for biological control of insect pests. However, the Trojan Y and several recombinant options that heritably distort pest population sex ratios are technologically feasible, are at or are close to proof-of-concept stage and are potentially much more effective than sterile male release programs. All genetic options at this stage require prolonged stocking programs to be effective, though gene drive systems are a potential for recombinant approaches. They are also likely to differ in their current degree of social acceptability, with chromosomal approaches (triploidy and Trojan Y) likely to be the most readily acceptable to the public and least likely to require changes in legislative or policy settings to be implemented. Modelling also suggests that the efficacy of any of these genetic techniques is enhanced by, and in turn non-additively enhance, conventional methods of pest fish control.

Ocean acidification has been predicted to reduce the ability of marine organisms to produce carbonate skeletons, threatening their long-term viability and severely impacting marine ecosystems. Corals, as ecosystem engineers, have been identified as particularly vulnerable and important. To determine the sensitivity of corals and allied taxa to long-term exposure to very low carbonate concentrations, we examined the distribution and skeletal characteristics of coral taxa along a natural deep-sea concentration gradient on seamounts of SW Australia. Carbonate undersaturation had little evident effect on the depth distribution, growth or skeletal composition of live scleractinians or gorgonians, with corals growing, often abundantly, in waters as much as 20 to 30% under-saturated. Developmental anomalies in the deepest skeleton-forming anthozoan collected (an isidid gorgonian, at nearly 4 km depth) suggest an absolute low tolerance limit of about 40% under-saturation. Evidence for an effect of acidification on the accumulation of reef structure is ambiguous, with clear indications of dissolution of high-magnesium calcite (HMC) gorgonian skeletons at depths below 2300 m, but also abundant, old scleractinian skeletons well below the aragonite saturation horizon. The latter might be the result of ferromanganese deposition on exposed skeletons, which, however, may render them inhospitable for benthic organisms.