<?xml version="1.0" encoding="utf-8"?>
    <rss version="2.0">
      <channel xmlns:content="http://purl.org/rss/1.0/modules/content/">
        <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>
        <generator>Frontiers Feed Generator,version:1</generator>
        <pubDate>2026-04-15T20:53:25.594+00:00</pubDate>
        <ttl>60</ttl>
        <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' ecology in inshore areas, 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>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1473376</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1473376</link>
        <title><![CDATA[Under pressure: deep-sea elasmobranchs experience high mortality and stress in a crustacean trawling fishery]]></title>
        <pubdate>2025-04-11T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Sofia Graça Aranha</author><author>Alexandra Teodósio</author><author>Tiago Marsili</author><author>Pedro Pires da Rocha</author><author>Teresa Modesto</author><author>Pedro M. Guerreiro</author><author>Aurélien Tambutte</author><author>Alexandra Alves</author><author>Paulo Relvas</author><author>Ester Dias</author>
        <description><![CDATA[Crustacean bottom trawling in southern Portugal is an economic and culturally important fishing activity but may result in considerable bycatch of deep-sea elasmobranchs (DSE). Due to DSE life-history strategies, at-vessel mortality (AVM) rates in crustacean bottom trawl fisheries are expectedly high but require further investigations. This study assessed the at-vessel condition of 18 species of DSE, and AVM rates and stress of four deep-sea shark species (Etmopterus pusillus, E. spinax, Galeus melastomus, and Scymnodon ringens), to understand the impact of bottom trawling on these animals. Opportunistic sampling on a crustacean trawler in the southern Portuguese coast, revealed that 95% of specimens were either dead (n = 1,258) or in poor condition (n = 224) upon collection, underscoring their minimal chance of post-release survival. General linear model analyses showed that AVM was species-specific and highest in smaller sharks, as well as in those from hauls that exhibited larger temperature differences between bottom and surface waters, and those caught in hauls with heavier codend weight using a 55 mm codend mesh (targeting shrimp and prawns) instead of those caught in hauls using a 70 mm codend mesh (targeting Norway lobster). Stress, evaluated through metabolites and electrolytes levels in sharks' plasma, indicated significant differences in potassium, urea, and magnesium levels between live and deceased specimens of E. pusillus and G. melastomus, suggesting these as reliable mortality markers. Elevated lactate levels in G. melastomus further pointed to high post-release mortality risk. These findings highlight an urgent need to find solutions to mitigate the impacts of bottom trawling on those DSE, which are thoroughly discussed. A coordinated, multi-stakeholder approach involving researchers, the fishing industry, and regulatory bodies is crucial for developing and implementing effective, and more sustainable fisheries management and protection of DSE populations.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1581493</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1581493</link>
        <title><![CDATA[Effect of different levels of environmental enrichment on the welfare of guppy (Poecilia reticulata)]]></title>
        <pubdate>2025-04-09T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Isabella Manenti</author><author>Benedetto Sicuro</author><author>Elisabetta Macchi</author><author>Patrizia Ponzio</author><author>Riccardo Crosetto</author><author>Sharon Cavallari</author><author>Martina Tarantola</author><author>Cecilia Mugnai</author>
        <description><![CDATA[IntroductionThe breeding of ornamental fish is increasingly widespread across the world. For this reason, assessing the welfare of ornamental fish in aquariums is becoming ever more important. This study wants to evaluate, through minimally invasive analyses, behavioral observations, and an analysis of cortisol concentrations in the water, how the absence or presence of environmental enrichment (EE) influences the welfare of guppies (Poecilia reticulata).MethodsIn total, 15 tanks, divided by EE level [without, with low (25%), and with high (75%) levels of EE], were considered. Fish were video-recorded and behavioral analyses were carried out. In addition, the cortisol concentrations in each tank's water were evaluated.ResultsIn the tanks with higher EE, behaviors such as wood, flotation, and plant feeding and courting, which are indicators of a good quality of life, were significantly more expressed. Bite behavior was also expressed more in high-level EE tanks, probably as a response to the territoriality of animals. The only stereotypy behavior, a stress index, was found to be significantly more expressed in tanks with low levels of EE. Finally, cortisol concentrations were found to be significantly higher in tanks with low levels of EE.DiscussionIn light of these results, we conclude that fish in tanks with higher EE levels showed better welfare statuses. Considering the use of EE in tanks is therefore useful for enabling these fish to express their species-specific behavioral repertoire and improve their quality of life.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1437507</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1437507</link>
        <title><![CDATA[First record of orcas (Orcinus orca) preying on a prickly shark (Echinorhinus cookei) in the Gulf of California: insights into shark ecology]]></title>
        <pubdate>2025-03-21T00:00:00Z</pubdate>
        <category>Brief Research Report</category>
        <author>Frida Lara-Lizardi</author><author>María Fernanda Gómez</author><author>Andrea Quintero-Perez</author>
        <description><![CDATA[The first documented instance of predation on a prickly shark (Echinorhinus cookei) by orcas (Orcinus orca) in the shallow waters of the southwestern Gulf of California, particularly around Cerralvo Island, is presented. The observation was made possible through a combination of local ecological knowledge and citizen science efforts, demonstrating the value of community involvement in marine research. Both the vulnerability of prickly sharks to industrial fishing and the deep- water sharks limited ecological knowledge in the Gulf of California emphasize the significance of this sighting. The findings underscore the necessity for ongoing research and conservation efforts, highlighting the importance of the integration of the local ecological knowledge and citizen science to protect this species' habitat in the Gulf of California and beyond.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1547935</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1547935</link>
        <title><![CDATA[Correlating environmental DNA and hydroacoustic estimates of biomass and abundance to monitor the globally Endangered mulloway (Argyrosomus japonicus)]]></title>
        <pubdate>2025-03-19T00:00:00Z</pubdate>
        <category>Brief Research Report</category>
        <author>Meaghan L. Rourke</author><author>Matt K. Broadhurst</author><author>Ashley M. Fowler</author><author>Julian M. Hughes</author><author>Joseph D. DiBattista</author><author>Stefan Sawynok</author><author>Elise M. Furlan</author>
        <description><![CDATA[Monitoring long-term spatiotemporal changes in populations of vulnerable species requires non-lethal methods. Here we investigate the utility of environmental DNA (eDNA) for estimating the relative biomass and abundance of the globally Endangered mulloway (Argyrosomus japonicus) in a southeastern Australian estuary. During minimal tidal movement, 10 parallel transects at each of 12 sites were surveyed, involving water samples being collected for determining eDNA concentrations of mulloway DNA prior to hydroacoustics being used to estimate their abundance and then biomass. There was no significant linear relationship between eDNA and abundance but there was for biomass, although the direction of differences varied seasonally, with positive and negative regressions observed during autumn and spring, respectively. As non-invasive survey methods, both eDNA and hydroacoustics require further validation, and such efforts should assess the influence of key environmental factors.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1550222</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1550222</link>
        <title><![CDATA[Metrics, scales, and correlates of intraspecific variation in hypoxia tolerance in fishes]]></title>
        <pubdate>2025-03-19T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Courtney H. Babin</author><author>Bernard B. Rees</author>
        <description><![CDATA[The extent of aquatic hypoxia (low dissolved oxygen) has increased in recent times and now threatens aquatic habitats worldwide. Here, we review intraspecific variation in hypoxia tolerance in fish on various scales: geographic variation among populations; variation among genetic strains; variation due to laboratory acclimation; and variation among individuals coming from a given population and having similar exposure history. Metrics of hypoxia tolerance include the oxygen level below which the costs of maintenance can no longer be met by oxygen uptake from the environment; the time or oxygen level at which aquatic surface respiration is conducted; and the time or oxygen levels at which fish lose the ability for coordinated movement. There is great diversity in the range of intraspecific hypoxia tolerance and its association with potential underlying morphological, physiological, and genetic correlates. We advocate for greater standardization of experimental design, enhanced data reporting, and development and validation of new metrics of hypoxia tolerance. With greater understanding of intraspecific variation in hypoxia tolerance, it might be possible to predict which populations, strains, or individuals will fare better during hypoxic episodes; mitigate the effects of low oxygen on fishes; and design breeding protocols to enhance the hypoxia tolerance of fishes.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2025.1525181</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2025.1525181</link>
        <title><![CDATA[How genomic and environmental relationships shape phenotypic plasticity in brook charr Salvelinus fontinalis: an historical review]]></title>
        <pubdate>2025-02-19T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Céline Audet</author><author>Dany Garant</author><author>Amélie Crespel</author><author>Marie Vagner</author>
        <description><![CDATA[This review revisits 20 years of collaborative studies that were pursued with Louis Bernatchez who sadly passed away in October 2023. With him, we explored the phenotypic plasticity of brook charr by combining ecophysiology, genetics, genomics, and more recently epigenetics. Over the years, we conducted extensive studies on brook charr, focusing on metabolism, stress response, growth regulation, and temperature tolerance across various strains. Our research highlighted the remarkable diversity in physiological responses to temperature and salinity conditions, along with significant differences in the heritability of key traits across different strains and life stages. We studied stages from yolk-sac fry to reproductive adults, compared freshwater residents and anadromous fish, and recently showed how epigenetics affects the physiological and transcriptomic responses of progeny to temperature conditions. This review highlights the incredible physiological plasticity of brook charr and presents future research avenues that will lead to a better understanding of how the species may face challenges related to global changes.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/frish.2024.1476026</guid>
        <link>https://www.frontiersin.org/articles/10.3389/frish.2024.1476026</link>
        <title><![CDATA[Pacific sailfish (Istiophorus platypterus) in the Eastern Pacific Ocean, association with ocean currents and seasonal effects of upwelling using real-time Argos locations]]></title>
        <pubdate>2025-01-21T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Chelsea E. Clyde-Brockway</author><author>Samir Harshad Patel</author><author>Gabriela Blanco</author><author>Samuel J. Friederichk</author><author>Stephen Morreale</author><author>Frank V. Paladino</author>
        <description><![CDATA[Pacific sailfish (Istiophorus platypterus) are the most abundant marlin in Central American waters and are a species of socioeconomic and ecological importance with sport fishing generating millions of dollars (USD) and thousands of jobs each year. Concurrently, sailfish are caught as bycatch in purse seine and longline fishing gear potentially threatening the stability of the population and sportfishing community. In this study, Wildlife Computers Mk10 satellite transmitters were deployed on sailfish (n = 6) which relayed real time Argos satellite locations and post-release light-derived geolocation positional estimates. The two location recording methods produced similar tracking intervals—deployment date until the final location date—(Argos: 33.0 ± 13.5 d; GPE: 32.0 ± 11.2 d), and detection days—number of days the transmitter recorded a location—(Argos: 7.8 ± 6.0 d; GPE: 12.3 ± 8.5 d). In total, displacement distances from initial tagging to final (Argos) location ranged from 339.92 to 985.59 km and crossed 6 different Exclusive Economic Zones. During migrating, sailfish exhibited alternating with-current and against-current movements, a pattern that was consistent in both the upwelling and non-upwelling seasons. Despite the known fluctuations associated with seasonal upwelling in the eastern Pacific, sailfish experienced relatively stable microenvironments with average temperature variability remaining within 2°C. Behavioral modification to achieve this consistency could be through depth use (48 ± 28 m vs. 37 ± 47 m), though this mechanism alone seems unlikely to fully explain their ability to mitigate environmental dynamics. Further research is needed to understand the mechanisms underlying these behavioral adaptations and the ecological factors that contribute to sailfish resilience. Additionally, strengthened protection measures are critical to ensure the conservation of sailfish in Costa Rica, including elimination of all commercial sale.]]></description>
      </item>
      </channel>
    </rss>