Life history traits of the temperate mini-maximalist Idiosepius notoides, (Cephalopoda: Sepioidea)

Age, growth and maturation of the temperate ‘mini-maximalist’ Idiosepius notoides from Tasmania is described and compared with those of its tropical congener Idiosepius pygmaeus. Using statolith increment analysis, growth of I. notoides was best described by a power curve with a maximum age of 115 days recorded. Males have a shorter lifespan than females, however growth rates were similar between the sexes. Idiosepius notoides grows to a larger size than its tropical counterpart. Onset of maturity in I. notoides occurred at an age of approximately 68 days for males and 88 days for females compared to 45-60 days for I. pygmaeus. Size at onset of sexual maturity was analogous between the two species, with males mature at approximately 6.5mm mantle length (ML) and females at 14.0mm ML. Idiosepius notoides, like I. pygmaeus, is a small short-lived sepioid with signi¢cant gender dimorphism and the capacity to spawn multiple times throughout its short life.This research supports the concept of similar cephalopod species living longer and growing larger in cooler environments

Maximising the utility of bioelectrical impedance analysis for measuring fish condition requires identifying and controlling for sources of error

Body condition indices are commonly used to represent the physiological status of fishes. Bioelectrical impedance analysis (BIA) has emerged as a rapid, nonlethal and cost-effective method for measuring fish condition and predicting proximate composition components, such as per cent fat. Measuring the condition of fish obtained from varied sources requires consideration of potential sources of error to ensure robust and comparable data are obtained. This is important when opportunistically applying BIA to assess fish condition for species that are logistically difficult to sample (e.g., large-bodied marine fishes), when different sampling methods are used, or where fish handling effects may confound condition comparisons. We experimentally tested the effects of five factors related to fish handling on an instantaneous body condition index (phase angle) measured using BIA. Using the coastal-pelagic yellowtail kingfish (Seriola lalandi) as a model species, we identified significant effects for four out of five factors tested: time since death, temperature of the tissue, removal of the gills and gastrointestinal tract, and the anatomic location for measurements. We propose protocol considerations when using BIA to opportunistically measure condition in fish obtained from varied sources. These sampling protocols for the robust application of BIA can maximise the utility of this approach for opportunistically measuring body condition in fish

Multiple measures of thermal performance of early stage eastern rock lobster in a fast-warming ocean region

To date, many studies trying to understand species’ climate-driven changes in distribution, or ‘range shifts’, have each focused on a single potential mechanism. While a single performance measure may give some insight, it may not be enough to accurately predict outcomes. Here, we used multiple measures of performance to explore potential mechanisms behind species range shifts. We examined the thermal pattern for multiple measures of performance, including measures of aerobic metabolism and multiple aspects of escape speed, using the final larval stage (puerulus) of eastern rock lobster Sagmariasus verreauxi as a model species. We found that aerobic scope and escape speed had different thermal performances and optimal temperatures. The optimal temperature for aerobic scope was 27.5°C, while the pseudo-optimal temperature for maximum escape speed was 23.2°C. This discrepancy in thermal performance indicators illustrates that one measure of performance may not be sufficient to accurately predict whole-animal performance under future warming. Using multiple measures of performance and appropriate modelling techniques may lead to a more accurate prediction of future range shifts, including the timing and extent of climate-driven species redistribution

Temperature alters the physiological response of spiny lobsters under predation risk

Predation risk can strongly shape prey ecological traits, with specific anti-predator responses displayed to reduce encounters with predators. Key environmental drivers, such as temperature, can profoundly modulate prey energetic costs in ectotherms, although we currently lack knowledge of how both temperature and predation risk can challenge prey physiology and ecology. Such uncertainties in predator–prey interactions are particularly relevant for marine regions experiencing rapid environmental changes due to climate change. Using the octopus (Octopus maorum)–spiny lobster (Jasus edwardsii) interaction as a predator–prey model, we examined different metabolic traits of sub adult spiny lobsters under predation risk in combination with two thermal scenarios: ‘current’ (20°C) and ‘warming’ (23°C), based on projections of sea-surface temperature under climate change. We examined lobster standard metabolic rates to define the energetic requirements at specific temperatures. Routine metabolic rates (RMRs) within a respirometer were used as a proxy of lobster activity during night and day time, and active metabolic rates, aerobic scope and excess post-exercise oxygen consumption were used to assess the energetic costs associated with escape responses (i.e. tail-flipping) in both thermal scenarios. Lobster standard metabolic rate increased at 23°C, suggesting an elevated energetic requirement (39%) compared to 20°C. Unthreatened lobsters displayed a strong circadian pattern in RMR with higher rates during the night compared with the day, which were strongly magnified at 23°C. Once exposed to predation risk, lobsters at 20°C quickly reduced their RMR by ~29%, suggesting an immobility or ‘freezing’ response to avoid predators. Conversely, lobsters acclimated to 23°C did not display such an anti-predator response. These findings suggest that warmer temperatures may induce a change to the typical immobility predation risk response of lobsters. It is hypothesized that heightened energetic maintenance requirements at higher temperatures may act to override the normal predator-risk responses under climate-change scenarios

Physiological mechanisms linking cold acclimation and the poleward distribution limit of a range-extending marine fish

Extensions of species’ geographical distributions, or range extensions, are among the primary ecological responses to climate change in the oceans. Considerable variation across the rates at which species’ ranges change with temperature hinders our ability to forecast range extensions based on climate data alone. To better manage the consequences of ongoing and future range extensions for global marine biodiversity, more information is needed on the biological mechanisms that link temperatures to range limits. This is especially important at understudied, low relative temperatures relevant to poleward range extensions, which appear to outpace warm range edge contractions four times over. Here, we capitalized on the ongoing range extension of a teleost predator, the Australasian snapper Chrysophrys auratus, to examine multiple measures of ecologically relevant physiological performance at the population’s poleward range extension front. Swim tunnel respirometry was used to determine how mid-range and poleward range edge winter acclimation temperatures affect metabolic rate, aerobic scope, swimming performance and efficiency and recovery from exercise. Relative to ‘optimal’ mid-range temperature acclimation, subsequent range edge minimum temperature acclimation resulted in absolute aerobic scope decreasing while factorial aerobic scope increased; efficiency of swimming increased while maximum sustainable swimming speed decreased; and recovery from exercise required a longer duration despite lower oxygen payback. Cold-acclimated swimming faster than 0.9 body lengths sec−1 required a greater proportion of aerobic scope despite decreased cost of transport. Reduced aerobic scope did not account for declines in recovery and lower maximum sustainable swimming speed. These results suggest that while performances decline at range edge minimum temperatures, cold-acclimated snapper are optimized for energy savings and range edge limitation may arise from suboptimal temperature exposure throughout the year rather than acute minimum temperature exposure. We propose incorporating performance data with in situ behaviour and environmental data in bioenergetic models to better understand how thermal tolerance determines range limits

Species on the move around the Australian coastline: a continental-scale review of climate-driven species redistribution in marine systems

Climate‐driven changes in the distribution of species are a pervasive and accelerating impact of climate change, and despite increasing research effort in this rapidly emerging field, much remains unknown or poorly understood. We lack a holistic understanding of patterns and processes at local, regional and global scales, with detailed explorations of range shifts in the southern hemisphere particularly under‐represented. Australian waters encompass the world's third largest marine jurisdiction, extending from tropical to sub‐Antarctic climate zones, and have waters warming at rates twice the global average in the north and two to four times in the south. Here, we report the results of a multi‐taxon continent‐wide review describing observed and predicted species redistribution around the Australian coastline, and highlight critical gaps in knowledge impeding our understanding of, and response to, these considerable changes. Since range shifts were first reported in the region in 2003, 198 species from nine Phyla have been documented shifting their distribution, 87.3% of which are shifting poleward. However, there is little standardization of methods or metrics reported in observed or predicted shifts, and both are hindered by a lack of baseline data. Our results demonstrate the importance of historical data sets and underwater visual surveys, and also highlight that approximately one‐fifth of studies incorporated citizen science. These findings emphasize the important role the public has had, and can continue to play, in understanding the impact of climate change. Most documented shifts are of coastal fish species in sub‐tropical and temperate systems, while tropical systems in general were poorly explored. Moreover, most distributional changes are only described at the poleward boundary, with few studies considering changes at the warmer, equatorward range limit. Through identifying knowledge gaps and research limitations, this review highlights future opportunities for strategic research effort to improve the representation of Australian marine species and systems in climate‐impact research

Body Size, Growth and Life Span: Implications for the Polewards Range Shift of Octopus tetricus in South- Eastern Australia

Understanding the response of any species to climate change can be challenging. However, in short-lived species the faster turnover of generations may facilitate the examination of responses associated with longer-term environmental change. Octopus tetricus, a commercially important species, has undergone a recent polewards range shift in the coastal waters of south-eastern Australia, thought to be associated with the southerly extension of the warm East Australian Current. At the cooler temperatures of a polewards distribution limit, growth of a species could be slower, potentially leading to a bigger body size and resulting in a slower population turnover, affecting population viability at the extreme of the distribution. Growth rates, body size, and life span of O. tetricus were examined at the leading edge of a polewards range shift in Tasmanian waters (40°S and 147°E) throughout 2011. Octopus tetricus had a relatively small body size and short lifespan of approximately 11 months that, despite cooler temperatures, would allow a high rate of population turnover and may facilitate the population increase necessary for successful establishment in the new extended area of the range. Temperature, food availability and gender appear to influence growth rate. Individuals that hatched during cooler and more productive conditions, but grew during warming conditions, exhibited faster growth rates and reached smaller body sizes than individuals that hatched into warmer waters but grew during cooling conditions. This study suggests that fast growth, small body size and associated rapid population turnover may facilitate the range shift of O. tetricus into Tasmanian waters

Towards a diagnostic approach to climate adaptation for fisheries

A diagnostic approach to climate change adaptation for fisheries is proposed to define potential climate adaptation pathways in well-managed fisheries. Traditional climate vulnerability and risk assessments tend to focus on biophysical threats and opportunities and thereby what needs to be done to adapt to climate change. Our diagnostic approach moves from such analysis to focus on how the processes of adaptation and development of adaptive capacity can be structured to achieve desired outcomes. Using a well-grounded framework, the diagnostic approach moves from system description to characterization of challenges and opportunities, through two stages of analysis and validation, to the definition and embedding of adaptation options and pathways. The framework can include all contextually relevant variables and accommodate evaluation of adaptation outcomes and comparisons across scales and contexts. Such an approach can serve as a basis for enabling stakeholders to identify challenges and opportunities, and to explore and prioritize options for development and implementation of legitimate adaptation pathways

Rapid shifts in distribution and high-latitude persistence of oceanographic habitat revealed using citizen science data from a climate change hotspot

The environmental effects of climate change are predicted to cause distribution shifts in manymarine taxa, yet data are often difficult to collect. Quantifying and monitoring species’suitable environmental habitats is a pragmatic approach for assessing changes in speciesdistributions but is underdeveloped for quantifying climate change induced range shifts inmarine systems. Specifically, habitat predictions present opportunities for quantifyingspatiotemporal distribution changes while accounting for sources of natural climate variation.Here we demonstrate the utility of a marine-based habitat model parameterised using citizenscience data and remotely-sensed environmental covariates for quantifying shifts inoceanographic habitat suitability over 22-years for a coastal-pelagic fish species in a climatechange hotspot. Our analyses account for the effects of natural intra- and inter-annual climatevariability to reveal rapid poleward shifts in core (94.4 km decade-1) and poleward edge(108.8 km decade-1) oceanographic habitats. Temporal persistence of suitable oceanographichabitat at high-latitudes also increased by approximately three months over the study period.Our approach demonstrates how marine citizen science data can be used to quantify rangeshifts, but necessitates shifting focus from species distributions directly, to the distribution ofspecies’ environmental habitat preferences

An assessment of how Australian fisheries management plans account for climate change impacts

For Australian fisheries to remain productive and sustainable (environmentally and commercially), there is a need to incorporate climate change considerations into management and planning, and to implement planned climate adaptation options. Here, we determine the extent to which Australian state fisheries management documents consider issues relating to climate change, as well as how frequently climate change is considered a research funding priority within fisheries research in Australia. We conduct a content analysis of fisheries management documents investigating categories and themes relating to Australian state fisheries, climate, and environmental change. We also reviewed recent Research Priorities from the major fisheries research funding body for reference to climate change related themes, and the number of subsequently funded projects which considered climate change or related topics. Results show that commercial state fisheries management documents consider climate only to a limited degree in comparison to other topics, with less than one-quarter of all fisheries management documents having content relating to climate. However, we find that the south-east and south-west regions of the Australian coastline have the highest incorporation of “climate” and “environmental protection considerations” in their fisheries management documents, and that fisheries are more likely to have more “climate-related mentions” within their related management documents, if they (i) primarily target species with higher economic commercial catch values, (ii) commercial catch weights, or (iii) a greater number of commercial fish stocks existing. Only a small number of recently funded fisheries research projects considered climate change, representing only a small proportion of fisheries research investment. Given the extensive climate-driven impacts recently documented among key Australian fisheries species and associated ecosystems, we conclude that there is a clear need for fisheries management in Australia to consider longer-term climate adaptation strategies for Australian commercial state fisheries to remain sustainable into the future. We suggest that without additional climate-related fisheries research and funding, many Australian agencies and fisheries may not be prepared for the impacts and subsequent adaptation efforts required for sustainable fisheries under climate change