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        <title>Frontiers in Fish Science | New and Recent Articles</title>
        <link>https://www.frontiersin.org/journals/fish-science</link>
        <description>RSS Feed for Frontiers in Fish Science | New and Recent Articles</description>
        <language>en-us</language>
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        <pubDate>2026-08-11T00:28:24.295+00:00</pubDate>
        <ttl>60</ttl>
        <item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2026.1734136</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2026.1734136</link>
        <title><![CDATA[Heavy metal trophic transfer and human health risks in the Northern Benguela current ecosystem: a review with a focus on cape hake species (Merluccius capensis and M. paradoxus)]]></title>
        <pubdate>2026-08-05T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Medusalem Jairus</author><author>Tamuka Nhiwatiwa</author><author>Johannes Angala Iitembu</author>
        <description><![CDATA[The Benguela Current Large Marine Ecosystem (BCLME), renowned for its high productivity, sustains vital fisheries, including the ecologically and economically crucial Cape hake (Merluccius capensis and M. paradoxus). This system faces threats from anthropogenic heavy metal (HM) pollution, primarily from industrial and mining activities, which jeopardizes ecosystem integrity and seafood safety. This review synthesizes current knowledge on trophic interactions and heavy metal (HM) transfer in the BCLME, focusing on Cape hake (Merluccius capensis and M. paradoxus) and their crustacean prey. Using a PRISMA structured systematic literature review of published literature, the review evaluates patterns of HM bioaccumulation and trophic transfer across marine food webs. Evidence indicates that mercury (Hg) is the most extensively studied and bioaccumulative metal, with concentrations generally increasing with trophic position marine organisms. Spatial variability in HM concentrations is influenced by environmental drivers such as upwelling intensity, sediment interactions, and coastal inputs, which affect metal bioavailability. However, important gaps remain, including limited data on non-mercury metals, seasonal variability, and multi-trophic level analyses within the BCLME. In addition, the application of trophic ecology tools, such as stable isotope analysis (SIA) and Bayesian mixing models (MixSIAR), remains underutilized in assessing contaminant pathways. These limitations constrain a comprehensive understanding of HM dynamics in the region. The review highlights the implications of HM bioaccumulation for ecosystem functioning, fisheries sustainability, and seafood safety in Namibia. Evidence from the reviewed studies indicates that mercury concentrations in most marine organisms generally remain below established food safety thresholds, suggesting a low immediate risk to consumers. Strengthening region-specific monitoring and integrating ecological and human health assessments will be essential for improving management under increasing environmental and anthropogenic pressures.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2026.1856912</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2026.1856912</link>
        <title><![CDATA[Omics-guided aquafeed innovation: raw ingredients to functional nutrition]]></title>
        <pubdate>2026-07-29T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Mir Ishfaq Nazir</author><author>Pankaj Gargotra</author><author>Oyas Asimi</author><author>Irfan Ahmad Bhat</author><author>Gowhar Iqbal</author><author>Mukilan Aakash</author>
        <description><![CDATA[The rapid expansion of aquaculture and the ongoing transition from marine derived feed ingredients have intensified the need for precise tools to evaluate alternative diet formulations. Traditional compositional analyses are increasingly insufficient for this purpose, as they lack the potential to capture molecular complexity of novel plant-based, insect based and single cell protein ingredients. High-throughput omics technologies like metabolomics, proteomics, transcriptomics, metagenomics, and epigenomics are filling the gaps by characterization of molecular interactions, including identification of bioactive phytochemicals, anti-nutritional factors, and quality markers. Then they are integrated with dynamic in-vitro gastrointestinal simulations systems, multi-omics data can support rational pre-selection of experimental functional feeds before animal trails, reducing cost and ethical burden. In vivo validation through controlled feeding trials, integrated with multi-omics analyses, then allows mechanistic elucidation of host-diet-microbiome interactions and systematic biomarkers discovery for feed efficiency assessment. Nutriepigenomics adds further dimensions by how early nutritional programming induces lasting epigenetics modifications in fish, with implications for long term diet assessment. Throughout, the extraordinary physiological diversity of teleosts in trophic strategy, gut morphology, and genomic resources imposes meaningful constraints on cross-species data interpretation that the field must acknowledge rigorously. Despite the challenges in standardization, cost, and large-scale validation, advances in artificial intelligence, portable analytics, and open access omics data bases are accelerating the translation of these technologies into practical feed innovation.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2026.1845924</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2026.1845924</link>
        <title><![CDATA[The quest for seal-safe fisheries—a comparison of alternative gear types in the Baltic Sea cod fishery]]></title>
        <pubdate>2026-07-01T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Peter Ljungberg</author><author>Edmond Sacre</author><author>Daniel Rooth</author><author>Sara Königson</author>
        <description><![CDATA[With recovering seal populations, there is a need to rethink fisheries technology and application to overcome economic and ecological obstacles while overcoming socially challenging situations. We have evaluated catchability, seal-induced damage, and potential commercial viability, considering handling time, of four passive fishing gear types: pots, pontoon traps, fyke nets, and gillnets in a seal-dense area. Results indicated that while gillnets initially exhibited the highest catch rates, they also experienced the most substantial seal damage, with over 50% of the catch affected. In contrast, pots and pontoon traps showed no seal damage, and fyke nets had an almost negligible damage rate of 2%. When extrapolated to a full day of fishing and accounting for handling time, fyke nets could potentially yield the highest average daily catch, followed by gillnets, pontoon traps, and pots. We conclude that alternative gear types, particularly fyke nets, along with pots and pontoon traps, show potential as more seal-safe and commercially viable alternatives to traditional gillnets in regions with high seal interaction where future research should focus on optimizing the design and handling of these alternative gears, and evaluating their performance across diverse conditions and scales.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2026.1820382</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2026.1820382</link>
        <title><![CDATA[First assessment of life history and spatial ecology of the endemic Raja Ampat epaulette shark (Hemiscyllium freycineti) in the Dampier Strait, Indonesia]]></title>
        <pubdate>2026-06-17T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Edy Setyawan</author><author>Ronald Mambrasar</author><author>Abdy W. Hasan</author><author>Orgenes Ambafen</author><author>Imanuel Mofu</author><author>Nesmus Saleo</author><author>Adrianus Urbata</author><author>Linus Mambraku</author><author>Deny Mambrasar</author><author>Hironimus Bani</author><author>Natasya Mambraku</author><author>Usal Mambraku</author><author>Ona Mambrasar</author><author>Decky Oniminya</author><author>Wehelmina Mambrasar</author><author>Giovani Sahusilawane</author><author>Leberina Rumbewas</author><author>Popaia Mambrasar</author><author>Eran Sauyai</author><author>Muhamad Izuan</author><author>Danang A. Prabowo</author><author>Abraham Sianipar</author><author> Fahmi</author><author>Mochamad Iqbal Herwata Putra</author><author>Mark V. Erdmann</author>
        <description><![CDATA[The Raja Ampat epaulette shark (Hemiscyllium freycineti) is an endemic species inhabiting shallow coastal habitats of the Raja Ampat Archipelago, Indonesia. Despite recent legal protection, information on its biology, population structure, and spatial ecology remains limited, constraining effective conservation. To address these gaps, a total of 64 nocturnal surveys (averaging 1.8–2.3 hours each) were conducted between February 2024 and April 2025 at six sites in the Dampier Strait region. Using photo-identification and passive integrated transponder tagging, 736 unique individuals were identified from 1,191 sightings, with most records from Arborek Island (n = 602). Of these, the population comprised 415 females and 321 males, resulting in a significantly female-biased sex ratio. Total length (TL) ranged from 19.4 to 75.0 cm (mean = 51.1 cm), and body mass ranged from 24 to 1,025 g (mean = 412.8 g). The length–weight relationships indicated negative allometric growth in both females (b = 2.91) and males (b = 2.81). Estimated length-at-maturity was 56.59 cm TL for females and 56.42 cm TL for males, with no significant difference between sexes. Relative density ranged from 333 to 2,462 individuals per km², representing the highest population density recorded globally for Hemiscyllium. A total of 256 individuals were resighted at least once, with resighting intervals extending up to 451 days. Immature individuals exhibited significantly higher growth rates than mature ones (7.8 vs 2.8 cm year-1), while no sex-specific difference in growth was detected. The best-supported and biologically meaningful growth model, seasonally oscillating ELEFAN with simulated annealing, estimated an asymptotic length (L∞) of 79.6 cm for all individuals, with a growth coefficient (K) of 0.747 year-1. Growth showed pronounced seasonal oscillations (C = 0.915). Sharks were most frequently observed in seagrass meadows. Habitat use analyses revealed ontogenetic partitioning. Coral reefs appear to function as a nursery habitat with 69% immature sharks, while seagrass and sand habitats supported higher proportions of adults. Individuals were highly resident, showed no inter-site movement, and occupied small spatial ranges, with maximum net displacements of 475 m. Collectively, these findings provide the first demographic and spatial baseline for H. freycineti in Raja Ampat.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2026.1828234</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2026.1828234</link>
        <title><![CDATA[Animal welfare in European caviar production: insights from sturgeon producers]]></title>
        <pubdate>2026-06-05T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Wasseem Emam</author><author>Matthew Unerman</author>
        <description><![CDATA[Sturgeon are long-lived, late-maturing species and are typically maintained in captivity for many years prior to roe collection, raising distinct welfare considerations compared with most other farmed fish. European producers account for a substantial proportion of farmed caviar, yet little is known about welfare conditions in commercial sturgeon broodstock systems. This exploratory study examined European caviar producers’ perspectives on production practices and animal welfare. Semi-structured interviews were conducted with eight participants representing approximately 20% of European caviar production. Participants were recruited with support from the Federation of European Aquaculture Producers Sturgeon Commission. Interviews were transcribed and analysed using thematic analysis. Three main themes were identified: (1) history of caviar production and species used in farming, (2) living conditions for sturgeon and (3) market considerations and external pressures. Producers consistently described strong links between water quality, stress reduction and feed management and the quality of caviar, suggesting that economic incentives may align with certain welfare-supportive practices. Divergent views were expressed regarding traditional slaughter versus no-kill extraction, with perceived welfare and quality trade-offs in both systems. This study provides initial insight into European sturgeon farming practices and identifies priority areas for independent welfare assessment and future research.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2026.1837236</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2026.1837236</link>
        <title><![CDATA[Neurobehavioral changes in response to trauma-like and contextual anxiety in zebrafish (Danio rerio): the modulatory influence of music]]></title>
        <pubdate>2026-05-22T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Ana Paula Giolo Franz</author><author>Emilly Baldissarelli</author><author>Amanda Corrêa dos Santos</author><author>Lisiane Siqueira</author><author>Wagner Antonio Tamagno</author><author>Carla Alves</author><author>Leonardo José Gil Barcellos</author>
        <description><![CDATA[IntroductionExposure to acute stress events, trauma, and intense anxiety can cause cognitive and memory deficits. This study investigated whether exposure to structured acoustic stimulation (classical music) modulates stress-induced cognitive impairments in adult zebrafish exposed to conspecific alarm substance (CAS), using the Y-maze test. MethodsFish were divided into groups, two of which were subjected to 15 days of Vivaldi’s classical music, with sound intensity between 65 and 75 dB SPL with predominantly measured frequencies between 330 and 506 Hz. One group was exposed to CAS before the acoustic stimulation (CAS + M), while another received the stimulation prior to CAS exposure (M + CAS). Additionally, two groups were exposed to CAS only, one on day 0 (CAS 0d) and the other on day 15 (CAS 15d), without any acoustic stimulation. A control group (CTL) was included without experimental manipulation. Spatial memory performance was assessed using the Y-maze test, and social behavior was evaluated through the shoaling test. Serum cortisol levels were measured as an index of physiological stress. ResultsExposure to CAS impaired exploratory behavior, evidenced by reduced time spent in the novel arm of the Y-maze. Consider this parameter as the main test outcome, post-stress acoustic stimulation restored exploratory performance to levels comparable to control fish, whereas prior exposure had no protective effect. Importantly, the CAS 15d group, which experienced the same temporal interval without acoustic stimulation, showed no recovery, supporting a specific effect of post-stress acoustic exposure on behavioral outcomes. CAS exposure significantly increased cortisol levels compared to controls; however, acoustic stimulation did not significantly attenuate this endocrine response. DiscussionTogether, these findings indicate that prolonged exposure to structured acoustic stimulation can modulate behavioral and cognitive responses following acute stress independently of cortisol normalization. The results support the use of zebrafish as an experimental model to investigate stress-induced cognitive dysfunction and highlight the relevance of acoustic environmental factors in post-stress behavioral modulation. Further studies are needed to elucidate the underlying neurobiological mechanisms and to determine the specificity of acoustic parameters involved.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2026.1758559</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2026.1758559</link>
        <title><![CDATA[Identifying spawning sites and fidelity of Ogaa (Walleye, Sander Vitreus): implications for fishery stewardship]]></title>
        <pubdate>2026-05-21T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Kayla Lenz</author><author>Aaron Shultz</author><author>Carl Klimah</author><author>Adam Ray</author>
        <description><![CDATA[Many giigoonyag (fishes) species worldwide display spawning site fidelity, making them especially susceptible to habitat disturbances in spawning areas. Identifying spawning sites and the degree of fidelity to these sites may be key to maintaining the relationship between humans and giigoonyag for future generations. Here, we use Indigenous knowledge to define Ogaa (Walleye Sander vitreus; singular) spawning periods, identify spawning sites, characterize habitat use, and quantify spawning site fidelity of 70 adult Ogaawag (Walleye; plural) during the 2019–2021 spawning seasons, in Mille Lacs Lake, Minnesota using an acoustic telemetry array. Ogaawag movements were tracked during the spring spawning period, and fish depth, number, and frequency of fish detected by each receiver were used to identify spawning sites and determine the relative importance of each spawning reef. Habitat characteristics such as substrate type, wind/wave action, and shoreline development were compared across reefs. We found that approximately 64% of Mille Lacs Ogaawag returned to the same site to spawn in 2020 as in 2019, 32% returned to the same site but also used other spawning areas, and only 4% used completely different spawning grounds across years. We identified areas with rocky and/or hard substrate, exposed to wind/wave action, and near undeveloped shorelines to be hotspots of Ogaawag activity during spawning. We also observed a rare example of skipped spawning by a female Ogaa. This study offers new insight into the rates of spawning site fidelity and the form that that fidelity takes in inland, fully-mixed waters, as well as provides evidence that Ogaa spawning hotspots may be correlated to areas of low or no onshore development. These findings may alter how humans act as stewards of this species, such as conserving spawning sites and adjacent habitats to improve recruitment and be a template for how Indigenous and Western societies can move toward a more inclusive life-history and ecosystem-based approach to sustaining their relationship with giigoonyag.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2026.1727267</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2026.1727267</link>
        <title><![CDATA[Return ticket: spatial use patterns of white sharks (Carcharodon carcharias) from a shark-bite mitigation program in eastern Australia]]></title>
        <pubdate>2026-04-13T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Gonçalo G. Ramos</author><author>Dean C. Blower</author><author>Nuno Queiroz</author><author>Paul A. Butcher</author>
        <description><![CDATA[The inherent susceptibility of white sharks (Carcharodon carcharias), coupled with reported declines in abundance, has led to their global listing as “Vulnerable”, prompting substantial conservation efforts. However, white sharks' propensity to use coastal areas overlaps with human activities, causing safety concerns. In New South Wales (NSW), Australia, they are caught as part of the world's longest-running meshing bather protection program. After an unprecedented spate of shark bites in 2015, Shark-Management-Alert-in-Real-Time (SMART) drumline trials started in NSW as a novel catch-and-release program aimed at non-lethal bather protection. Using seven years of data, this study analyzed SMART drumline recapture events to describe white shark habitat use along the NSW coastline. In total, 890 individuals were tagged with a recapture rate of 24.5% (n = 218). Smaller individuals (fork length < 225 cm) and females were more commonly recaptured, suggesting size and sex-specific habitat preferences. Although recaptures occurred year-round and throughout the entire NSW coast, most occurred during the Austral winter and spring and along the northern NSW coast. There were few consecutive recaptures recorded in the same location, suggesting that white sharks move throughout relatively large ranges within coastal areas. Linear distances between recaptures were on average ~220 (SE ± 25) km, mostly representing northward travels. Despite some variation, most recaptures (~77%) were recorded within a year and ~45% within 90 days. These results are consistent with the described movement ecology for the species along NSW, corroborating the seasonal importance of NSW northern coast for juvenile white sharks, and the potential effect that the Eastern Australian Current has on their distribution. This study provides important insights into immature white sharks' inshore ecology, highlighting the value of capture-mark-recapture data collected from SMART drumlines to forecast shark movement for enhanced bather safety and species management.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2026.1716016</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2026.1716016</link>
        <title><![CDATA[Fishing ground expansion and its consequences for estimates of sustainability in artisanal coral reef fisheries]]></title>
        <pubdate>2026-03-23T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Tim Rice McClanahan</author>
        <description><![CDATA[Sustainable fisheries require balancing ecological production with resource capture, but this balance is often obscured by changes in the fishing area. Further, expansion of fishing grounds is commonly proposed to mitigate overfishing by dispersing effort and promoting nearshore recovery, but its long-term consequences remain poorly understood. We evaluated artisanal coral reef fisheries along Kenya's fringing reef over a 23-year period, comparing ecological and fisheries production in non-expanded and expanded fishing grounds. Seventy percent of landing sites expanded by an average of 5% annually. Fishery catches were assessed against ecological production using fish censuses (1987–2024) and a biomass-production model (R2 = 0.78). Area changes significantly influenced per-area effort and catch estimates, requiring interpolation between initial and final measurements. Across all methods, capture consistently exceeded ecological production estimates, indicating unsustainable capture rates. Both area categories exhibited an effort–catch resource capture overshoot dynamic, with expanded areas showing delayed but more pronounced declines in per-area effort and yield after peak catches. Future yield projections varied with area estimation methods, expansion status, and catchability assumptions and projected that expansion would delay the time required to restore optimal yields. These findings highlight that fishing ground expansion is a less efficient use of fishing area, excludes several more efficient gears and livelihoods, slows recovery, and does not guarantee sustainability, or high long-term employment or yields. Detecting these patterns required regular evaluation of multiple fisheries and fisheries' independent variables, long-term assessments of effort, area, and ecological production. Moreover, simple time series and future projection methods can promote recommendations that hide the resource overshoot dynamic caused by a misalignment and time lags between production and capture rate estimates.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2026.1733032</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2026.1733032</link>
        <title><![CDATA[Improved estimates of growth for wild Yellowtail Kingfish (Seriola lalandi) off eastern-Australia using multiple data sources]]></title>
        <pubdate>2026-03-13T00:00:00Z</pubdate>
        <category>Brief Research Report</category>
        <author>John Stewart</author><author>Sarah Stuart</author><author>Julian M. Hughes</author><author>David J. Booth</author>
        <description><![CDATA[Unbiased growth functions are imperative for stock assessment and sustainable management of fisheries. We present a case-study demonstrating implications of data collection biases from fishery-dependent sampling where length-selective fishing occurs. Yellowtail Kingfish Seriola lalandi supports substantial fisheries around the world and is the focus of a developing aquaculture industry. Estimating growth rates in wild populations has been challenging, with uncertainties around accurate estimates of length-at-age from which to model growth. Length-at-age data are generally derived from sectioned sagittal otoliths. We generated new estimates of growth rates for Yellowtail Kingfish from south-eastern Australia by excluding data for age classes not fully recruited to the fishery based on significance tests of normality and skewness. New length-at-age estimates for young fish were generated from dive surveys around offshore Fish Aggregation Devices (FADs) to inform early growth. Otolith-derived age classes younger than 5 years old were biased in terms of faster growing individuals being sampled. Length-selective biases from fishery dependent sampling results in over-estimation of the von Bertalanffy growth function parameter L∞ and under-estimation of the parameters K and t0. Revised growth function parameters of L∞ = 133.40 cm fork length, K = 0.13 year -1, and t0 = −1.20 years are substantially different from those used for stock assessment. We recommend that future studies of growth rates would benefit from more fishery-independent sampling, the collection of greater numbers of larger and older fish, and regular sampling and direct aging of young-of-the year fish recruiting to offshore FADs.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2026.1746803</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2026.1746803</link>
        <title><![CDATA[Increasing lifting-bag mesh size to reduce codend occlusion in Australian whiting (Sillago spp.) trawls]]></title>
        <pubdate>2026-01-28T00:00:00Z</pubdate>
        <category>Brief Research Report</category>
        <author>Matt K. Broadhurst</author>
        <description><![CDATA[Some small-meshed fish-trawl codends require so-called “protective,” “strengthening,” or “lifting” bags for structural support, but these can occlude mesh openings and reduce size/species selectivity. This study compared two lifting-bag mesh sizes (94 and 216 mm stretched mesh opening; SMO) surrounding a 46-mm SMO codend in an Australian whiting-trawl fishery. During 37 deployments off Newcastle, New South Wales, compared to the 94-mm lifting bag, the 216-mm lifting bag significantly reduced the catches of juvenile eastern school whiting (Sillago flindersi <17 cm total length; TL) by ~35% and small unwanted velvet leatherjacket (Meuschenia scaber) by ~67%. Total bycatch declined by ~50%. However, ~6% of eastern school whiting ≥17 cm TL also escaped, along with some important byproduct species. Relative size–frequency analysis revealed no significant TL effects for eastern school whiting although there was evidence of fewer individuals being retained with the larger-meshed lifting bag. The data reiterate species-specific lifting-bag effects and the importance of evaluating both conservation benefits and economic impacts when subtly modifying trawl configurations.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1730596</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1730596</link>
        <title><![CDATA[Spawning patterns and reproductive biology of yellowtail scad (Trachurus novaezelandiae) off south-eastern Australia]]></title>
        <pubdate>2026-01-12T00:00:00Z</pubdate>
        <category>Brief Research Report</category>
        <author>John Stewart</author><author>Anne-Marie Hegarty</author><author>Caitlin Young</author><author>Antony Gould</author><author>James Craig</author>
        <description><![CDATA[We characterized the reproductive biology of the ecologically and commercially important small pelagic fish Trachurus novaezelandiae (yellowtail scad) in south-eastern Australian waters using a 25-year monitoring dataset. Sexual maturity occurred at 15.5 cm fork length (FL), with 95% of individuals mature by 23.2 cm FL. There were no significant differences in maturity ogives between sexes. Trachurus novaezelandiae exhibited an extended spawning season from July to March, peaking in October during the austral spring, consistent with sympatric small pelagic species in eastern Australian waters. Sex ratios in the commercial purse-seine fishery through 10 years were significantly skewed toward females (58%) and were consistent through years. Similarly to some other species within the Trachuridae, females predominated in all months except for those immediately following the spawning season, suggesting some differential sex-based availability to the fishery related to spawning. The fishery for T. novaezelandiae is currently classified as sustainable, with relatively low fishing mortality applied to the population. However, commercial harvests of small pelagic teleosts are rapidly increasing in Australian waters, and with developing markets it is likely that T. novaezelandiae will be fished more intensively in the future. The baseline information on reproductive biology in the present study may support sustainable exploitation through improved estimates of spawning stock biomass.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1708976</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1708976</link>
        <title><![CDATA[Catecholamines as central modulators of the stress response. A preliminary study in Atlantic salmon (Salmo salar) head kidney cells]]></title>
        <pubdate>2025-11-26T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Angelico Madaro</author><author>Victoria Warth Basso</author><author>Rolf Erik Olsen</author>
        <description><![CDATA[This study investigated the contribution of catecholamines to stress regulation in Atlantic salmon, with the goal of clarifying inconsistencies between the classical model of cortisol control in teleosts and recent observations that challenge it. According to the traditional theory, cortisol secretion is driven primarily by adrenocorticotropic hormone (ACTH) through activation of the hypothalamic–pituitary–interrenal (HPI) axis. However, several studies in salmonids have reported that elevations in cortisol can occur in the absence of, or prior to, measurable increases in ACTH. To examine whether catecholamines influence cortisol production we performed ex vivo incubations of head kidney tissue either with ACTH (10−6 M, 10−8 M, and 10−10 M), or catecholamine (adrenaline and noradrenaline, 10−6 M, 10−8 M for both) and monitored cortisol production up to 60 min post-incubation. The results confirmed that ACTH elicited a cortisol response, but not catecholamines. However, when head kidneys were incubated with combinations of ACTH (10−6 M) and catecholamines (adrenaline or noradrenaline, 10−7 M each) there was a massive increase in cortisol (by ~2.4-fold) production far exceeding that of ACTH alone. These findings suggest that catecholamines are unlikely to function as independent stimulators of cortisol synthesis but will enhance the responsiveness or sensitivity of interrenal cells to ACTH. Such a synergistic interaction could represent an adaptive mechanism enabling rapid cortisol elevation during acute stress, thereby helping to reconcile discrepancies between ACTH and cortisol profiles reported in vivo. Overall, this work provides new insight into the interplay between sympathetic activation and endocrine regulation in teleost fish.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1591515</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1591515</link>
        <title><![CDATA[How the resilient ecophysiology of the sea lamprey allowed them to invade the Laurentian Great Lakes and could protect them from climate change]]></title>
        <pubdate>2025-10-27T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Michael P. Wilkie</author>
        <description><![CDATA[Native to the Atlantic Ocean, anadromous sea lamprey (Petromyzon marinus) likely invaded the Laurentian Great Lakes in the mid 1800's-early 1900's following construction of the Erie Canal. Initially restricted to Lake Ontario, and some smaller nearby lakes, they entered Lake Erie via the Welland Canal in the early 1900s. Sea lamprey quickly became established in Lake Erie (1921), from which they invaded the three upper Great Lakes. Along with overharvest, predation (parasitism) by blood-feeding sea lamprey devastated commercial, sport and Indigenous fisheries including lake trout (Salvelinus namaycush) and whitefish and ciscoes (Coregonus sp.) populations. To deal with the crisis, the Great Lakes Fishery Commission (GLFC) was founded in 1955 with a mandate to eradicate sea lamprey. Sea lamprey were not eradicated, but a comprehensive sea lamprey control (SLC) program brought populations under control using barriers (dams) and traps to prevent spawning by adult lampreys, and chemical control using lampricides that selectively targeted larval sea lamprey in nursery streams draining into the lakes. In this synthesis the sea lamprey invasion is explored through the lens of “invasion theory” to characterize the likely vectors that introduced sea lamprey into the Great Lakes ecosystem, and to establish what eco-physiological features of sea lamprey led to their establishment and spread. The weight of evidence suggests that pre-existing adaptations and a robust physiology facilitated the sea lamprey's invasion of the Great Lakes. Key features likely included: (i) facultative anadromy, which allowed them to complete their entire life cycle in fresh water, (ii) a generalist diet enabling them to feed on a wide variety of fishes, (iii) the high fecundity of females that expedited their spread, (iv) a resilient thermal physiology, and (v) the availability of similar, suitable spawning and nursery habitat to that found in their native ranges. Many of these features may make sea lamprey relatively resilient to climate change, with changes in water temperature, water quality and hydrology having both negative and positive effects on the distribution of invasive populations in the Great Lakes, and imperiled populations native to the Western and Eastern Atlantic Ocean, and the Mediterranean Sea.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1672665</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1672665</link>
        <title><![CDATA[Editorial: Patterns, causes and consequences of intraspecific variation in environmental tolerance in fishes]]></title>
        <pubdate>2025-09-02T00:00:00Z</pubdate>
        <category>Editorial</category>
        <author>David J. McKenzie</author><author>Katja Anttila</author>
        <description></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1580250</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1580250</link>
        <title><![CDATA[Bottom trawl surveys show a sharp decline in European eel (Anguilla anguilla) abundance in northern European coastal waters]]></title>
        <pubdate>2025-08-12T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Henrik Svedäng</author>
        <description><![CDATA[Almost 50 years ago, the first signs of population decline in the European eel (Anguilla anguilla) were observed when upstream migration of yellow eel and catches of silver eel decreased in the Baltic Sea. Since then, the decline in recruitment has continued throughout the eel's range, and many indices based on early life stages are now hovering at extremely low levels. Consequently, the European eel is considered critically endangered, which has been linked to overfishing and habitat destruction, including barriers, spread of parasites, contaminants, and climate change. Measurements of European eel escapement are considered difficult to obtain because return sea migrations occur diffusely from all possible coasts, including marine habitats. Currently, the main source of data is the reported commercial landings data, which are subject to several uncertainties. Such uncertainties make evaluating stock status and the efficiency of eel management plans (EMPs) difficult. In this study, data on eel catches are presented from fishery independent international trawl surveys, which often is a more consistent data source than fisheries-dependent data (i.e., tag returns and landing reports from commercial fisheries). The trawl survey data presented here show drastic declines in eel abundance over the last 30–35 years throughout the Baltic Sea, the Kattegat, and the southern North Sea both regardless of size and in the group of larger eels (≥50 cm). This decline in abundance of larger eels calls into question the effectiveness of national EMPs and the future of the European eel.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1542342</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1542342</link>
        <title><![CDATA[Patterns of inter-populational and inter-individual variation in tolerance of sublethal progressive hypoxia and warming in the European seabass Dicentrarchus labrax]]></title>
        <pubdate>2025-07-11T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Julie J. H. Nati</author><author>Charles Rodde</author><author>Felipe R. Blasco</author><author>Germain Salou</author><author>Alain Vergnet</author><author>Hugues de Verdal</author><author>Marc Vandeputte</author><author>François Allal</author><author>David J. McKenzie</author>
        <description><![CDATA[We compared tolerance of acute progressive hypoxia and warming in the three recognized populations of European seabass, Atlantic (AT), West Mediterranean (WM) and East Mediterranean (EM), that have evolved within a North-West to South-East thermal gradient, from AT to EM. We reared progeny of captive broodstock in common garden at two temperatures, 18 and 24°C, representing summer temperatures in Atlantic and East Mediterranean, respectively. At about 1 year of age, hypoxia tolerance was evaluated with static respirometry, as critical saturation for regulation of standard metabolic rate (Scrit) and regulation index (RI); while warming tolerance was evaluated by swimming respirometry, as critical thermal maximum for aerobic swimming (CTSmax). We expected AT fish systematically to be least tolerant and EM most, with WM intermediate. At 18°C, the tolerance traits were similar among populations, but they responded differently when reared at 24°C. In AT and WM, Scrit increased—tolerance declined—from 18 to 24°C, whereas in EM it did not change. In AT and WM, RI did not change from 18 to 24°C whereas in EM it increased—tolerance increased, and EM had higher RI than WM at 24°C. In AT and EM, CTSmax was similar at 18 and 24°C whereas in WM it increased—tolerance increased, and WM had higher CTSmax than AT and EM at 24°C. Therefore, the EM population is able to avoid negative effects of warmer water on hypoxia tolerance, compared to AT and WM, but this was not related to improved thermal tolerance at the warmer temperature, where WM performed better than AT and EM. Consequently, the seabass exhibits inter-populational variation in tolerance of the stressors but patterns are complex and not consistent between hypoxia and warming. We explored some potential patterns of inter-individual variation in tolerance. We found no evidence that individuals relatively tolerant of hypoxia (low Scrit, high RI) were also relatively tolerant of warming (high CTSmax). There was evidence of complex relationships with body mass, whereby tolerance of warming declined with increasing mass at 18°C but tolerance of hypoxia increased with mass at 24°C. Finally, the traits of tolerance were not dependent on individual standard metabolic rate at either temperature.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1520995</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1520995</link>
        <title><![CDATA[Novel observations of an oceanic whitetip (Carcharhinus longimanus) and tiger shark (Galeocerdo cuvier) scavenging event]]></title>
        <pubdate>2025-05-29T00:00:00Z</pubdate>
        <category>Brief Research Report</category>
        <author>Molly Scott</author><author>Olivia Miller</author><author>Devon Stapleton</author><author>Kayleigh Grant</author>
        <description><![CDATA[Oceanic whitetip sharks, Carcharhinus longimanus, are known to be common scavengers; however, observations of C. longimanus scavenging events are extremely rare due to their classification as an oceanic pelagic species, typically solitary in nature. On April 9, 2024, over 8.5 h, at least nine C. longimanus were observed scavenging from a heavily degraded carcass off the coast of Kailua-Kona, Hawai‘i, USA. Five tiger sharks (Galeocerdo cuvier) were also observed scavenging on the same carcass. Simultaneous feeding within and between species occurred; however, no agonistic or aggressive interactions were observed. Although a small snapshot, this stochastic event sheds new light on trophic relationships and social interactions among aquatic apex predators that do not normally overlap in space and time.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1414859</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1414859</link>
        <title><![CDATA[Trophic and feeding ecology of whale sharks (Rhincodon typus) using bulk stable isotope analysis]]></title>
        <pubdate>2025-05-22T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Clare E. M. Prebble</author><author>Lydie I. E. Couturier</author><author>Christoph A. Rohner</author><author>Simon J. Pierce</author><author>Clive N. Trueman</author>
        <description><![CDATA[IntroductionDespite their size, relatively passive behavior, and commercial significance, knowledge of the behavioral ecology of whale sharks remains limited. The difficulty of tracking individual animals at sea encourages the use of retrospective biochemical approaches such as stable isotope analysis.MethodsWhale sharks at Mafia Island in Tanzania form a comparatively small and resident aggregation that has been monitored for several successive years, providing a rare opportunity to study biochemical changes in individuals over time. In this study, 53% of the identified individuals were sampled at the time of collection over a multi-year period. Stable isotope analysis was performed on these samples to investigate their feeding ecology.ResultsStable isotope data suggest that whale sharks at Mafia Island predominantly feed within the local food web at a trophic level consistent with current understanding of the species' general feeding ecology. These data also reveal a range of individual feeding strategies within the local aggregation, with some sex and size-related differences. However, the isotopic niche area at the population level was relatively constrained.DiscussionWe call for additional research and emphasize the importance of a multi-faceted approach incorporating diverse biochemical and tracking techniques to more accurately understand the long-term feeding ecology of this endangered and charismatic mega-planktivore.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1571172</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1571172</link>
        <title><![CDATA[Multiple fishways mostly maintain upstream teleost movement in a south-eastern Australian river]]></title>
        <pubdate>2025-04-30T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Meaghan L. Rourke</author><author>Wayne Robinson</author><author>Lee J. Baumgartner</author><author>Jonathon Doyle</author><author>Martin Mallen-Cooper</author><author>Jason D. Thiem</author><author>Matt K. Broadhurst</author>
        <description><![CDATA[River development affects fish connectivity, with intra-river issues exacerbated via sequential barriers. Remediation typically involves installing ‘fishways' to facilitate upstream movements. Here we evaluated species-specific upstream fish-passage efficiencies through three sequential vertical-slot fishways along the Nepean River in Australia via paired entry and exit trapping. Species-specific water velocity preferences associated with fishway entrance were informed by restricting head loss at the entry traps, but not at the exit traps. During 78 paired trap deployments 26,139 fish were caught, comprising 19 species; most of which successfully negotiated the fishways—albeit with considerable inter- and intra-specific variability among fishways. Catches of the most abundant species (38% of total), the amphidromous Gobiomorphus coxii (20–160 mm total length; TL), in the entry and exit traps were negatively and positively affected by water velocity, respectively at the second and third fishways, but not at the first. Catches of other species were also directly or indirectly affected by water velocity, with fewer catadromous Trachystoma petardi (145–460 mm fork length; FL) and Mugil cephalus (35–410 mm FL) recorded in entry than exit traps, implying (1) insufficient water velocity to permit entry and/or (2) confounding effects of the entry-trap design on capture. Conversely, two gudgeons [the potamodromous Philypnodon grandiceps (29–77 mm TL) and Hypseleotris galii (31–49 mm TL)] were caught in significantly greater abundances in the entry than exit traps implying some restriction to their passage and possibly due to deficits in fishway hydraulics and/or a lack of motivation to migrate in these species. The study highlights the value of location-specific monitoring for identifying key factors affecting fishway performance.]]></description>
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