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Swordfish ( Xiphias gladius ) are a widely distributed (45°N–45°S) large pelagic fish targeted by fisheries worldwide. Swordfish that occur at high latitudes tend to disproportionately be large adults, so their movements have implications for population dynamics and fisheries management. In the southwest Pacific, little is known about this subset of the stock and existing evidence suggests limited movement from the subtropics into cooler high latitude waters. Here, we capitalize on the recent emergence of a recreational swordfish fishery off temperate southeast Australia to characterize movements of swordfish caught in the fishery with pop-up satellite archival transmitting tags. Data were recovered from tags deployed for 56–250 days on 11 swordfish (50–350 kg) tagged between 38 and 43°S in the western Tasman Sea. Five swordfish entered the Coral Sea (< 30°S), with four reaching north to 11–24°S, up to 3275 km away from location of capture. Behavior modelling suggests these four individuals rapidly transited north until encountering 23–27 °C water, at which point they lingered in the area for several months, consistent with spawning-related partial migration. One migrating swordfish still carrying a tag after the spawning season returned to ~ 120 km of its release location, suggesting site fidelity. Movements toward the central south Pacific were confined to two individuals crossing 165°E. Swordfish predominantly underwent normal diel vertical migration, descending into the mesopelagic zone at dawn (median daytime depth 494.9 m, 95% CI 460.4–529.5 m). Light attenuation predicted daytime depth, with swordfish rising by up to 195 m in turbid water. At night, swordfish were deeper during the full moon, median night-time depth 45.8 m (37.8–55.5) m versus 18.0 m (14.9–21.8) m at new moon. Modelling fine-scale (10 min −1 ) swordfish depth revealed dynamic effects of moon phase varying predictably across time of night with implications for fisheries interactions. Studying highly migratory fishes near distribution limits allows characterization of the full range of movement phenotypes within a population, a key consideration for important fish stocks in changing oceans.

Many species of reef fishes form spawning aggregations during predictable seasons and lunar phases, which are often targeted by fishers, leading to their depletion over time. In Palau, a new fisheries management plan will protect the Longnose Emperor ( Lethrinus olivaceus ) at an assumed spawning aggregation site around the full moon; however, whether and/or when this species forms spawning aggregations in Palau was unclear. We investigated lunar and seasonal patterns in fish density using diver operated stereo-video surveys 5–8 days around the new moon between February 2023 and February 2024 at the aggregation site. Gonad samples were collected from the aggregation site and local fish market to assess spawning and trends in gonadosomatic index (GSI). Aggregation site new moon fish densities were over 6x greater than full moon densities and other reference sites, and densities peaked during the new moon. The peak aggregation months were February to May, September and October. Hydrated oocytes in gonad samples indicated active spawning at the aggregation site, and GSI was greatest around the new moon. Our results provide multiple lines of evidence that the Longnose Emperor forms spawning aggregations around the new moon in Palau and will be critical to inform fisheries management reforms.

Abstract Fishing is one of the most sustained forms of human–wildlife interaction and can alter trait distributions through selective harvest and repeated disturbance. Such changes, whether plastic or evolutionary, may alter productivity, resilience, and recovery in exploited species. The sand flathead (Platycephalus bassensis), a benthic ambush predator with strong site fidelity, supports lutruwita (Tasmania’s) largest recreational fishery and is exposed to contrasting levels of fishing pressure across its range. In southern Tasmania, fishing mortality exceeds natural mortality more than fivefold and biomass has fallen below 20% of unfished levels, while northern regions remain comparatively lightly fished. This regional contrast offers a natural setting in which to investigate whether sustained harvest is associated with regional differences in physiology and behaviour, and whether such variation is more consistent with fishing pressure, environmental conditions, or their interaction. We compared mass-specific metabolic rate, boldness, and size-at-age between sand flathead from heavily and lightly fished regions. Metabolic rate was measured using intermittent flow-through respirometry, and boldness was quantified in a shuttlebox based on exploration latency and bait strikes. Fish from the heavily fished south exhibited smaller size-at-age, a 62% higher mean metabolic rate, and a transient post-capture elevated metabolic rate consistent with greater metabolic reactivity or stress responsiveness, whereas boldness did not differ between regions. Our findings align with other exploited systems and raise the possibility that trait diversity of sand flathead in southern regions of Tasmania have been shaped, at least in part, by fisheries selection. We discuss the relevance of these results for fisheries management and emphasize the importance of assessing trait variation in wild populations, where expression is likely shaped by the interactive effects of fishing pressure and local ecological conditions. Lay Summary We compared traits of sand flathead from heavily and lightly fished regions of Tasmania. Fish from heavily fished areas were smaller for their age and had higher metabolic rates, showing that fish populations can differ in growth and energy use across regions with contrasting fishing pressure.

Aim Climate-driven extensions of species distributions have serious consequences for human wellbeing and ecosystems. The recent growth of citizen science data collection represents an underutilised resource for the early detection of marine species range extensions (i.e., expansion of species' distributions at the poleward edge) that can enable proactive conservation and management. Here, we present a framework for the systematic assessment of evidence for marine species range extensions along a continent's coastlines from observations collected by different citizen science programmes. Location Australia's coastal oceans. Methods Observations of 200 marine species on a pre-registered target list from around Australia during 2013–2022 were sourced from the citizen science databases Redmap Australia, iNaturalist, and Reef Life Survey. We established historical (circa 2012) poleward distribution limits for populations of target species and identified out-of-range (poleward of distribution limit) observations, which underwent expert validation. We assessed the likelihood that each species underwent range extension using a decision tree informed by citizen science observations and species traits. Results In total, 73 species (39%) were observed out-of-range, comprising 76 range extensions along different coastlines. Twenty-five range extensions were assessed as high confidence, five with medium confidence, and 46 with low confidence. Range extensions were concentrated in Australia's southwest (Western Australia) and southeast (New South Wales and Tasmania), which are influenced by warm boundary currents and considered ocean warming hotspots. The mean extent of range extensions was 318 km (max. 1250 km). Main Conclusions As most (91%) range extensions identified were not previously described in the scientific literature from other data, we demonstrate that opportunistic citizen science monitoring can provide early detection of marine species range extensions at the continental scale. Given the varied consequences of range-extending species for recipient ecosystems, effectively harnessing citizen science would critically enhance the capacity for needed targeted research and anticipatory management efforts.

The identification of practical early diagnostic biomarkers is a cornerstone of improved prevention and treatment of cancers. Such a case is devil facial tumor disease (DFTD), a highly lethal transmissible cancer afflicting virtually an entire species, the Tasmanian devil ( Sarcophilus harrisii ). Despite a latent period that can exceed one year, to date DFTD diagnosis requires visual identification of tumor lesions. To enable earlier diagnosis, which is essential for the implementation of effective conservation strategies, we analyzed the extracellular vesicle (EV) proteome of 87 Tasmanian devil serum samples using data-independent acquisition mass spectrometry approaches. The antimicrobial peptide cathelicidin-3 (CATH3), released by innate immune cells, was enriched in serum EV samples of both devils with clinical DFTD (87.9% sensitivity and 94.1% specificity) and devils with latent infection (i.e., collected while overtly healthy, but 3-6 months before subsequent DFTD diagnosis; 93.8% sensitivity and 94.1% specificity). Although high expression of antimicrobial peptides has been mostly related to inflammatory diseases, our results suggest that they can be also used as accurate cancer biomarkers, suggesting a mechanistic role in tumorous processes. This EV-based approach to biomarker discovery is directly applicable to improving understanding and diagnosis of a broad range of diseases in other species, and these findings directly enhance the capacity of conservation strategies to ensure the viability of the imperiled Tasmanian devil population.

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.

Barred sand bass Paralabrax nebulifer (Family: Serranidae; BSB) are among the most popular recreational game fishes in southern California and an important food fish. Patterns of residency and habitat use are critical for determining the potential for BSB to be impacted by point source anthropogenic contaminants prevalent in the densely populated coastal environment near Los Angeles, California. Home ranging behavior, degree of site fidelity, residency, habitat selection, and seasonal spawning migration of BSB were observed over 27 mo using a large, continuous coverage, fine-scale acoustic telemetry array (~20 km²). The 55 tagged individuals used small core areas (mean ± SD = 2682 ± 2005 m² over 329 ± 227 d) and showed high affinity for the rock/sand ecotone at a depth of 20 to 30 m. Overall weekly residency to the array was 70 ± 25% of tagged fish present from the first tag date through the end of the study, with lower residency during the summer spawning season (June to August). Individuals leaving the array emigrated in a southeasterly direction 98% of the time, and 100% of the BSB detections outside the array occurred to the southeast of the Palos Verdes Shelf Superfund Site (PVSSS; 26.4 ± 0.8 km). BSB of legal size (<360 mm TL) exhibit high long-term site fidelity to small areas within the PVSSS and make seasonal migrations to spawning aggregations beyond the boundaries of the ‘do not consume’ zone defined by the Office of Environmental Health Hazard Assessment in 2009.

Reef predators play a critical role in maintaining the balance of marine ecosystems and are an important component of Hawaii’s recreational and commercial fisheries. In response to the increasing anthropogenic demands on these populations across the main Hawaiian Islands, the study of predator movements in marine protected areas has become a research priority. To this aim, we used passive acoustic telemetry to investigate the spatial and temporal movement patterns of five reef predator species: bluefin trevally ( Caranx melampygus ), giant trevally ( Caranx ignobilis ), green jobfish ( Aprion virescens ), whitetip reef sharks ( Triaenodon obesus ) and gray reef sharks ( Carcharhinus amblyrhynchos ) at the 31 ha Molokini Marine Life Conservation District (MLCD) off Maui, Hawaii (Lat: 20°37′56.70″N, Lon: 156°29′44.52″W) from November 13, 2013 to August 28, 2015. Our results indicate that the predator assemblage in the MLCD was dominated by teleost fishes during the day and sharks at night. Residency was variable across species, with bluefin trevally exhibiting the highest residency in the MLCD, green jobfish the lowest, and long-distance movements between the Molokini MLCD and the other islands of the Maui Nui Complex were common for gray reef sharks and giant trevally. These results indicate that despite its small size, the Molokini MLCD provides a high level of protection to resident species such as bluefin trevally. However, this MLCD is less effective at protecting more mobile predators such as green jobfish, gray reef sharks and giant trevally.

Citizen science programs are effective methods to collect large volumes of data to assist researchers in monitoring ecological environments. As species shift their distributions globally due to climate change, the use of citizen science data to detect these shifts is increasing. Using targeted citizen science programs to collect data on these species could provide information on range edges to inform species distribution modelling. Currently, species distribution models (SDMs) often rely on large data repositories that may lack observations, and hence ability, to detect changes at the range edge. Here, we developed a SDM to compare traditional data repository observations with targeted citizen science data at the southern distribution limit of two recreationally important marine fish in Tasmania, Australia to investigate the potential change in spatial predictions at their range edge. The SDM using the targeted citizen science data in addition to traditional observation data improved the representation of species by 2.3 and 52.7% and increased the southern distribution of the species by 277 and 438 km, for snapper and King George whiting, respectively. Future (centred around 2050 under IPCC RCP 8.5) habitat suitability was predicted to increase more over the winter season, with implications for species overwintering and persistence of populations. The use of citizen science data allowed for the modelling of historical and future change for two range-extending species, an outcome possible due to the collaboration of two citizen science programs that collected observational data on the target species. Species range shifts will require ongoing monitoring and we have demonstrated that complimentary citizen science initiatives are effective in capturing occurrences of species at their range edge. Increasing collaboration between programs may further increase data collection efforts and provide the knowledge to create a hub for these data to be used more efficiently in the future.

The identification of practical early diagnosis biomarkers is a cornerstone of improved prevention and treatment of cancers. Such a case is devil facial tumour disease (DFTD), a highly lethal transmissible cancer afflicting virtually an entire species, the Tasmanian devil (Sarcophilus harrisii). Despite a latent period that can exceed one year, to date DFTD diagnosis requires visual identification of tumour lesions. To enable earlier diagnosis, which is essential for the implementation of effective conservation strategies, we analysed the extracellular vesicle (EV) proteome of 87 Tasmanian devil serum samples. The antimicrobial peptide cathelicidin-3 (CATH3) was enriched in serum EVs of both devils with clinical DFTD (87.9% sensitivity and 94.1% specificity) and devils with latent infection (i.e., collected while overtly healthy, but 3-6 months before subsequent DFTD diagnosis; 93.8% sensitivity and 94.1% specificity). As antimicrobial peptides can play a variety of roles in the cancer process, our results suggest that the specific elevation of serum EV-associated CATH3 may be mechanistically involved in DFTD pathogenesis. This EV-based approach to biomarker discovery is directly applicable to improving understanding and diagnosis of a broad range of diseases in other species, and these findings directly enhance the capacity of conservation strategies to ensure the viability of the imperilled Tasmanian devil population. Competing Interest Statement The authors have declared no competing interest.