Fisheries Research最新文献_第10页

The effects of ENSO on spatial-temporal distribution and growth rate of three cryptic mullet species in Taiwan ENSO对台湾三种隐鲻鱼时空分布及生长速率的影响

IF 2.3 2区农林科学 Q2 FISHERIES

Fisheries Research

Pub Date : 2025-11-01 Epub Date: 2025-09-23 DOI: 10.1016/j.fishres.2025.107538

Yu-Ling Nien , Nan-Jay Su , Ching-Ping Lu , Hsueh-Jung Lu , Chia-Hui Wang

This study investigates the impact of ENSO on the species composition and growth during the early-life history of three cryptic mullet species (NWP1–3) in the estuaries around Taiwan. Juvenile mullets were identified using genetic method, and their growth rates were analyzed using generalized additive models (GAMs) based on biological and environmental variables. The results found that NWP2 was the most abundant species, dominating several months and estuaries. NWP1 had lower abundance than NWP2, but its proportion was relatively higher in La Niña and rarer in El Niño. NWP3 exhibited the lowest abundance, but expanded spatially during El Niño. Moreover, the growth of juvenile mullet was influenced by multiple factors annually, especially sea surface temperature (SST) and drifting growth rate (DGR). The environmental changes induced by ENSO and species-specific traits simultaneously impact both the distribution and growth patterns of cryptic mullet species. Both these factors directly influence species composition and indirectly affect species abundance by modifying growth and mortality rates. Consequently, lower SST during La Niña year benefited the abundance and growth of NWP1, while higher SST during El Niño year benefited NWP3 population. Although NWP2 maintained high abundance annually, rising SST may impact the growth of this species. These findings underscore the critical role of interannual environmental variability in regulating the distribution, abundance, and growth during the early life stages of cryptic mullet species in subtropical estuarine systems.

本研究探讨ENSO对台湾沿岸河口三种隐鲻鱼（NWP1-3）早期生活史的物种组成及生长的影响。采用遗传方法对鲻鱼幼鱼进行鉴定，并利用基于生物和环境变量的广义加性模型（GAMs）对其生长速率进行分析。结果发现，NWP2是最丰富的物种，在几个月和河口占主导地位。NWP1丰度低于NWP2，但在La Niña中所占比例相对较高，在El Niño中较少。NWP3丰度最低，但在El Niño期间呈空间扩张趋势。此外，鲻鱼幼鱼的生长受多种因素的影响，尤其是海温（SST）和漂流生长率（DGR）。ENSO引起的环境变化和物种特异性性状同时影响隐鲻鱼的分布和生长模式。这两个因素都直接影响物种组成，并通过改变生长和死亡率间接影响物种丰度。因此，La Niña年较低的海温有利于NWP1种群的丰度和生长，而El Niño年较高的海温有利于NWP3种群。尽管NWP2每年都保持高丰度，但海温的上升可能会影响该物种的生长。这些发现强调了在亚热带河口系统中，年际环境变异在调节隐鲻鱼的分布、丰度和早期生长过程中的关键作用。

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引用次数: 0

Investigation of shell banding in an arcid cockle alongside trace-element concentrations to evaluate potential suitability for age estimation 在一个酸性蛤壳带的调查与微量元素浓度，以评估年龄估计的潜在适用性

IF 2.3 2区农林科学 Q2 FISHERIES

Fisheries Research

Pub Date : 2025-11-01 Epub Date: 2025-09-10 DOI: 10.1016/j.fishres.2025.107522

Patrick Reis-Santos , Rhiannon A. Van Eck , Charlotte Gauthier , Joseph B. Widdrington , Rowan C. Chick , Bronwyn M. Gillanders , Matthew D. Taylor

Arcid clams or cockles (Arcidae) are widespread sediment-associated bivalves that support commercial, recreational and cultural fisheries. Despite their importance, ageing in these species has received little attention, constraining stock assessment to length-based models and data limited approaches. In this context, sclerochronology (growth increments) and sclerochemistry (chemical proxies) offer valuable tools for population analysis and environmental reconstructions. Here, we investigated shell banding in Sydney Cockle (Anadara trapezia) alongside shell chemistry to assess the potential suitability for ageing. Specifically, we examined whether variation in Mg:Ca and Sr:Ca was associated with shell bands, as a means of validating seasonal growth increments. Banding patterns correlated closely with seasonal variation in shell chemistry, and application of innovative peak detection algorithms (spline quantile regression, and split moving window analysis) to chemical data improved the objectivity of increment identification, particularly for Mg:Ca and in larger, older shells. Overall, the results indicated that dark shell bands in Sydney Cockle are most likely annuli, and are likely to be appropriate for determining age composition and growth in the species. By enhancing objectivity and consistency, particularly for Mg:Ca, our integrated approach supports more robust age and growth assessments. The protocol developed for ageing and chemical analysis is relevant for ageing other arcid cockle species, but further validation work will improve confidence in ageing data using this approach.

海蛤或蛤（海蛤科）是广泛分布的与沉积物有关的双壳类动物，支持商业、娱乐和文化渔业。尽管这些物种很重要，但它们的老化问题却很少受到关注，这使得种群评估仅限于基于长度的模型和数据有限的方法。在这种情况下，硬化年代学（生长增量）和硬化化学（化学代用物）为种群分析和环境重建提供了有价值的工具。在这里，我们研究了悉尼蛤（Anadara trapezia）的壳带和壳化学，以评估老化的潜在适应性。具体来说，我们研究了Mg:Ca和Sr:Ca的变化是否与壳带有关，作为验证季节性生长增量的一种手段。条带模式与贝壳化学的季节变化密切相关，将创新的峰值检测算法（样条分位回归和分裂移动窗口分析）应用于化学数据，提高了增量识别的客观性，特别是对Mg:Ca和更大、更老的贝壳。总体而言，结果表明悉尼贝的深色壳带最有可能是环空，并且可能适合于确定该物种的年龄组成和生长情况。通过提高客观性和一致性，特别是镁钙的客观性和一致性，我们的综合方法支持更稳健的年龄和生长评估。为老化和化学分析制定的方案与其他酸蛤物种的老化有关，但进一步的验证工作将提高使用这种方法的老化数据的信心。

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引用次数: 0

The capability of electronic monitoring to measure logbook reporting performance and improve data for scientific analyses 电子监控的能力，以衡量日志报告的性能和改进数据的科学分析

IF 2.3 2区农林科学 Q2 FISHERIES

Fisheries Research

Pub Date : 2025-11-01 Epub Date: 2025-09-09 DOI: 10.1016/j.fishres.2025.107518

Timothy J. Emery, Rocio Noriega, Mahdi Parsa, Don Bromhead, Trent Timmiss

Electronic monitoring (EM) systems are used to collect fisheries dependent data to support scientific analyses and management decision-making. In Australian Commonwealth fisheries, EM is also used to validate and improve logbook data reporting at the individual vessel level through the provision of consistent feedback to fishers on their logbook reporting. We compared five years of EM and logbook reported catch numbers for both retained and discarded key tuna and billfish species and, interactions with endangered, threatened and protected (ETP) species in the Australian Eastern Tuna and Billfish Fishery (ETBF). This was undertaken to examine congruence at an individual vessel level and determine how both EM and logbook reporting can potentially be improved in the future. At a fleet-wide level, overall congruence was higher for retained than discarded catch and higher for ETP groups (i.e., seabirds) than at an ETP species (i.e., wandering albatross) taxonomic level. Importantly, vessel-level estimates of congruence revealed significant inter-vessel variation in logbook reporting performance. For example, a small number of vessels were not reporting any bycatch and discards despite EM analysts observing these occurrences on these vessels, whilst other vessels had perfect congruence for some species across all audited sets. These results highlight the capability of EM to identify vessels with general (i.e. universal) or specific (e.g. particular species) logbook reporting deficiencies, that enable managers to undertake either incentive-based, education-based or (where required) compliance-based targeted actions to ensure that those vessels improve their future logbook reporting. Ultimately this approach will improve data inputs for scientific analyses and the fisheries management decisions that rely on them.

电子监测系统用于收集渔业相关数据，以支持科学分析和管理决策。在澳大利亚联邦渔业中，EM还通过向渔民提供一致的日志报告反馈，在单个船只层面上验证和改进日志数据报告。我们比较了澳大利亚东部金枪鱼和长嘴鱼渔业（ETBF）中保留和丢弃的主要金枪鱼和长嘴鱼物种的5年EM和日志报告的捕捞数量，以及与濒危、受威胁和受保护（ETP）物种的相互作用。这是为了检查单个船舶水平的一致性，并确定未来如何改进EM和日志报告。在全船队水平上，保留渔获物的总体一致性高于丢弃渔获物，ETP类群（如海鸟）的总体一致性高于ETP物种（如信天翁）的分类一致性。重要的是，船舶水平的一致性估计揭示了日志报告性能在船舶间的显著差异。例如，尽管EM分析师在这些船只上观察到这些情况，但少数船只没有报告任何副渔获物和丢弃物，而其他船只在所有被审计的集合中对某些物种具有完美的一致性。这些结果突出了EM识别船舶的一般（即通用）或特定（例如特定物种）日志报告缺陷的能力，使管理人员能够采取基于激励，基于教育或（必要时）基于合规性的针对性行动，以确保这些船舶改善其未来的日志报告。最终，这种方法将改善科学分析的数据输入和依赖这些数据的渔业管理决策。

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引用次数: 0

Cod highly infected with the parasitic nematode Contracaecum osculatum demonstrates stunted growth: A controlled laboratory experiment with ad libitum feeding 高度感染了寄生线虫的鳕鱼表现出生长迟缓：一项自由摄食的对照实验室实验

IF 2.3 2区农林科学 Q2 FISHERIES

Fisheries Research

Pub Date : 2025-11-01 Epub Date: 2025-09-18 DOI: 10.1016/j.fishres.2025.107532

Jane W. Behrens , Marie Plambech Ryberg , Jakob Hemmer-Hansen , Maria Krüger-Johnsen , Anders Nielsen , Niels Gerner Andersen

Predatory fish in the wild and in particular Eastern Baltic cod Gadus morhua are facing varying and unpredictable feeding opportunities. This implies a high assimilative capacity including nutritional state-related hyperphagia to maintain long-term positive energy balance. Heavy infection of cod livers by the parasitic nematode Contracaecum osculatum is suspected to jeopardize the assimilative capacity and thus the vital rates, growth, reproduction and mortality of the cod population. We examine the effect of C. osculatum on growth, condition and liver weight of cod in laboratory experiments with ad libitum feeding. We find that highly infected cod displays reduced hepatosomatic index and reduced or negative growth and change in condition factor. We suggest that in the wild, cod also with lower infection levels may be constrained by an impaired liver capacity as they here also face feeding constraints. Measurements of growth hormone expression together with knowledge about the endocrine regulation of appetite and growth are used to explain the data. We find strong indications that for cod with high infection level this plays a significant role for all the three vital population rates, and that these effects should be considered in the management of the cod stock in the eastern Baltic Sea.

野生掠食性鱼类，特别是波罗的海东部鳕鱼正面临着变化莫测的捕食机会。这意味着高的同化能力，包括营养状态相关的贪食，以维持长期的正能量平衡。鳕鱼肝脏被寄生线虫镰状缩孔虫严重感染，可能危及鳕鱼的同化能力，从而影响鳕鱼种群的生长率、生长、繁殖和死亡率。在实验室试验中，采用自由放养的方法，研究了隐状梭菌对鳕鱼生长、状况和肝脏重量的影响。我们发现，高感染的鳕鱼表现为肝体指数降低，条件因子减少或负增长和变化。我们认为，在野外，感染水平较低的鳕鱼可能受到肝脏功能受损的限制，因为它们在这里也面临着进食限制。生长激素表达的测量以及对食欲和生长的内分泌调节的了解被用来解释这些数据。我们发现强有力的迹象表明，对于高感染水平的鳕鱼，这对所有三种重要种群率都起着重要作用，并且在波罗的海东部鳕鱼种群的管理中应考虑到这些影响。

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引用次数: 0

A meta-analysis of immediate and delayed discard mortality of red snapper (Lutjanus campechanus) 红鲷鱼（Lutjanus campechanus）即刻和延迟丢弃死亡率的荟萃分析

IF 2.3 2区农林科学 Q2 FISHERIES

Fisheries Research

Pub Date : 2025-11-01 Epub Date: 2025-09-09 DOI: 10.1016/j.fishres.2025.107524

Chloe Ramsay , Matthew D. Campbell , Beverly Sauls

Red snapper (Lutjanus campechanus) is an economically important fishery in the Gulf of America (formerly the Gulf of Mexico). This species is subject to discard mortality due to barotrauma. Novel discard mortality research on this species has estimated delayed mortality in addition to immediate mortality at the surface (i.e., swim or float). To determine how this combined mortality measurement changes red snapper discard mortality, we conducted a meta-analysis, combining 11 studies, with 92 distinct estimates from 34 years of research. We assessed if depth, season, release method, or region predict discard mortality. We found a significant positive relationship between depth and discard mortality and that, in the western Gulf, fishing in the summer significantly increases discard mortality compared to fishing in other seasons and regions. Analysis of studies with well-defined release method treatments revealed that venting and descending generates a 14.6 % decrease in estimated release mortality compared to no barotrauma mitigation. We estimate a 31 % discard mortality at 33 m, the median fishing depth of the private recreational fleet; this is more than double the discard mortality estimate generated by a previous meta-analysis based on immediate mortality alone. Given that we generated estimates from both immediate mortality and delayed mortality, we propose that these updated, higher estimates of discard mortality are more representative of the mortality experienced by this recreational fishery.

红鲷鱼（Lutjanus campechanus）是美国海湾（以前的墨西哥湾）经济上重要的渔业。由于气压创伤，这一物种容易死亡。对该物种的丢弃死亡率的新研究估计了除了在水面（即游泳或漂浮）立即死亡之外的延迟死亡。为了确定这种综合死亡率测量方法如何改变红鲷鱼的丢弃死亡率，我们进行了一项荟萃分析，结合了11项研究，以及34年研究中的92种不同估计。我们评估了深度、季节、释放方法或区域是否能预测丢弃死亡率。我们发现深度和弃物死亡率之间存在显著的正相关关系，在西部海湾，与其他季节和地区相比，夏季捕鱼显著增加了弃物死亡率。采用明确的释放法治疗的研究分析显示，与不缓解气压创伤相比，通气和下降可使估计的释放死亡率降低14.6% %。我们估计在33 米（私人休闲船队的中位捕鱼深度）的弃置死亡率为31% %；这是先前仅基于即时死亡率的荟萃分析得出的丢弃死亡率估计的两倍多。考虑到我们从即时死亡率和延迟死亡率中得出的估计值，我们建议这些更新的、更高的弃置死亡率估计值更能代表这种休闲渔业所经历的死亡率。

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引用次数: 0

Evidences of formation of predominant calcite polymorphs in otoliths of the fishes of riverine environment 河流环境鱼类耳石中方解石多晶形成的优势证据

IF 2.3 2区农林科学 Q2 FISHERIES

Fisheries Research

Pub Date : 2025-11-01 Epub Date: 2025-10-17 DOI: 10.1016/j.fishres.2025.107552

Lubna Yasmeen, Mohd Sadiq, Mohd Hammad, Ameer Hamza, Begum Raziya Nargis, Mohammad Afzal Khan

Fish otoliths record biological and environmental history through a metabolically driven biomineralization process. The otolith's crystalline structure is due to the presence of calcium carbonate polymorphs that may influence trace element chemistry; thus, understanding otolith polymorphs is essential. This study employs confocal micro-Raman spectroscopy to investigate the crystalline polymorphs in otoliths of three freshwater fishes (Heteropneustes fossilis, Channa punctata, and Labeo bata) from the River Ganga. In all three fishes, Raman signals showed the strong calcite band intensities of v₁ stretching mode at 1087 cm⁻¹ and weak signals of lattice mode at 154.9 cm⁻¹, aragonite band intensities of v₄ vibrational mode at 707 cm⁻¹ and lattice mode at 208 cm⁻¹. The vaterite band intensities of the lattice mode were recorded in L. bata and C. punctata. The mean baseline-corrected Raman intensities were highest for calcite in all three fishes. The results suggested that calcite is the predominant polymorph in the selected fish species. The replacement of calcium by barium was mapped as witherite (BaCO₃) in H. fossilis and C. punctata. The Kruskal-Wallis and post hoc Dunn’s test revealed significant differences among nearly all polymorph intensities. The findings can help to understand the biological processes involved in otolith formation and growth. Further detailed research is warranted to decipher the ecological factors that could have led to the relative abundance of calcite polymorphs in the target fish species.

鱼耳石通过代谢驱动的生物矿化过程记录了生物和环境历史。耳石的晶体结构是由于碳酸钙多晶体的存在，可能影响微量元素的化学性质；因此，了解耳石的多态是必不可少的。本研究利用共聚焦微拉曼光谱研究了恒河三种淡水鱼（Heteropneustes化石、Channa punctata和Labeo bata）耳石中的晶体形态。在这三种鱼类中，拉曼信号显示v1拉伸模式的强方解石波段强度为1087 cm−1，晶格模式的弱信号为154.9 cm−1，文石波段强度为v4振动模式的707 cm−1和晶格模式的208 cm−1。记录了白莲花和刺花花晶格模式的紫外带强度。在所有三种鱼类中，方解石的平均基线校正拉曼强度最高。结果表明，方解石是所选鱼类的优势多态性。在石楠和石楠中，钙被钡取代，被定位为枯萎石（BaCO3）。Kruskal-Wallis和post - hoc Dunn测试揭示了几乎所有多晶型强度之间的显著差异。这一发现有助于了解耳石形成和生长的生物学过程。进一步的详细研究是必要的，以破译生态因素，可能导致方解石的多态性相对丰富的目标鱼类。

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引用次数: 0

Productivity versus engineering-based approaches to measure effort creep over time 随着时间的推移，生产力与基于工程的方法来衡量工作的蠕变

IF 2.3 2区农林科学 Q2 FISHERIES

Fisheries Research

Pub Date : 2025-11-01 Epub Date: 2025-10-03 DOI: 10.1016/j.fishres.2025.107546

Trevor Hutton, Sean Pascoe, Denham Parker

Most fisheries stock assessments rely on fishery dependent data to a large extent, with catch per unit effort a key indicator of changes in stock conditions. However, increases in fishing efficiency due to changes in technology and physical fleet attributes distort the relationship between observable effort (e.g., days or hours fished), catch and biomass. To compensate, a key component of fisheries stock assessment is the estimation of changes in fishing power over time to adjust catch rate information for this “effort creep”. Two approaches have developed in parallel for estimating changes in efficiency of fishing vessels over time. An approach commonly applied in stock assessment is engineering-based, focusing on changes in physical inputs. In contrast, economic based approaches have developed for assessing efficiency change that also capture non-physical inputs such as fisher skill, management changes and resulting behavioural change. We apply both of these approaches to the Australian Northern Prawn Fishery (NPF) and test the degree to which the derived efficiency time series agree. We find that the two series are highly correlated and cointegrated, suggesting that both provide a consistent measure of efficiency change over time. In the case of the NPF, this validates the current method used to adjust for effort creep in the stock assessments.

大多数渔业种群评估在很大程度上依赖于依赖渔业的数据，单位努力渔获量是种群状况变化的关键指标。然而，由于技术和船队物理属性的变化而提高的捕鱼效率扭曲了可观察到的渔获量（例如，捕鱼的天数或小时数）、渔获量和生物量之间的关系。为了补偿，渔业资源评估的一个关键组成部分是估计随时间的捕捞能力变化，以调整这种“努力蠕变”的捕捞率信息。同时发展了两种方法来估计渔船效率随时间的变化。通常用于库存评估的一种方法是以工程为基础的，侧重于实物投入的变化。相比之下，以经济为基础的评估效率变化的方法也包括非物质投入，如渔民技能、管理变化和由此产生的行为变化。我们将这两种方法应用于澳大利亚北方对虾渔业（NPF），并测试所得效率时间序列一致的程度。我们发现这两个系列是高度相关和协整的，这表明两者都提供了一个一致的效率变化随时间的衡量标准。在NPF的情况下，这验证了用于调整存量评估中工作量蠕变的当前方法。

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引用次数: 0

Seasonal dynamics of the reproductive effort and first maturity of Chinese hat snails Trochita trochiformis (Born, 1778) in Guerrero, Mexico: Towards a sustainable fishery management 1778年生于墨西哥格雷罗的中国帽螺（Trochita trochiformis）繁殖努力和首次成熟的季节动态：走向可持续渔业管理

IF 2.3 2区农林科学 Q2 FISHERIES

Fisheries Research

Pub Date : 2025-11-01 Epub Date: 2025-09-06 DOI: 10.1016/j.fishres.2025.107520

Juan Carlos Cerros-Cornelio , Rafael Flores-Garza , Alma Rubí Castrejón-Ríos , Jesús Guadalupe Padilla-Serrato , Pedro Flores-Rodríguez , Carmina Torreblanca-Ramírez , Carmen Rodríguez-Jaramillo , José Luis García-Corona

The Chinese hat snail Trochita trochiformis is a valuable gastropod for artisanal fisheries on the southeast coast of Guerrero, in the Mexican Pacific. The knowledge of the reproductive biology of this species is of the utmost importance to assess the renewal capacity of natural stocks, thus ensuring sustainable management strategies, particularly in the case of this heavily exploited resource. Here, we investigated gametogenesis, reproductive effort and the size at first maturity of T. trochiformis over a 2-year cycle using qualitative and quantitative histological techniques. Gonad development was classified into 6 different stages for both males and females, ranging from immature to spent sexual structures. Moreover, the first records of protandric sex reversal were reported for this species. Snails were able to reproduce throughout the year, with maximum peaks of gonad development occurring during winter at minimal sea surface temperatures of around 27 °C; whereas spawning and short periods of gametogenic inactivity were observed with rising temperatures (27 °C to ∼31 °C) through spring and summer. The results suggest that female gonads have superior breeding capacity than males, yielding the highest oocyte quality during winter. Shell diameter at first maturity (SD₅₀) was estimated for the first time for this species at 44.8 mm for females, and 45.4 mm for males. Therefore, females are prone to overfishing since nearly 12 % of males changed to females after adult size in this study. Based on these results, two management measures could be applied: 1) a banning period from December to February during the season of greatest reproductive effort, and 2) an initial minimal capture size of ∼45 mm, thus allowing the snails to spawn at least once during the reproductive cycle.

中国帽螺Trochita trochiformis是墨西哥太平洋格雷罗东南海岸手工渔业的宝贵腹足类动物。了解这一物种的生殖生物学对于评估自然种群的更新能力，从而确保可持续的管理战略，特别是在这种被大量开发的资源的情况下，是极为重要的。本研究利用定性和定量组织学技术，研究了2年周期内疣状体虫的配子体发生、繁殖努力和初成熟时的大小。男性和女性的性腺发育分为6个不同的阶段，从未成熟到成熟的性腺结构。此外，还首次报道了该物种的原雄性性反转。蜗牛全年都能繁殖，性腺发育的高峰出现在冬季，海面最低温度约为27°C；而在春季和夏季，随着温度的升高（27°C至~ 31°C），观察到产卵和短时间的配子体不活动。结果表明，雌性性腺的繁殖能力优于雄性，在冬季产生的卵母细胞质量最高。首次测定了该物种的初熟壳直径（SD50），雌虫为44.8 mm，雄虫为45.4 mm。因此，雌性容易过度捕捞，在本研究中，接近12% %的雄性在成年后变为雌性。根据这些结果，可以采取两项管理措施：1)在繁殖最活跃的季节，从12月到次年2月实行禁捕期；2)最初的最小捕获尺寸为~ 45 mm，从而使蜗牛在繁殖周期中至少产卵一次。

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引用次数: 0

In situ target strength measurements of Peruvian anchovy (Engraulis ringens) from data collected by a commercial echosounder during fishing operations 根据商业回声测深仪在捕鱼作业期间收集的数据对秘鲁凤尾鱼（Engraulis ringens）的原位目标强度进行测量

IF 2.3 2区农林科学 Q2 FISHERIES

Fisheries Research

Pub Date : 2025-11-01 Epub Date: 2025-09-15 DOI: 10.1016/j.fishres.2025.107534

Martin Santivañez-Yuffra , Nathaly Pereira-Letona , Cynthia Vasquez-Paredes

Although fishing vessels have been used as opportunistic scientific platforms in the last two decades, target strength (TS) studies based on industry-collected data are still scarce. Here we present an in situ TS estimation of Peruvian anchovy (Engraulis ringens) from data recorded by a 120 kHz Simrad ES60 commercial echosounder mounted on the purse-seiner “Maru” in May-July 2017 during its fishing operations on North-Center stock area. TS-length (L) relationships (TS=a Log₁₀ (L)+b, with b= b₂₀ when a= 20) were estimated from pooled data using a curve fitting method. Influence of depth (Z) on TS was also investigated. Mean TS of 10–16.5 cm individuals was −54.2 dB (±0.2 dB) with corresponding a, b and b₂₀ values of 22.2, −79.5 dB and −77 dB. TS showed strong dependence with depth following Boyle’s law: TS= 20Log₁₀(L)-6.4Log₁₀(1-Z/10)-73.3 dB (r²=0.8). Our TS and b₂₀ estimates are in line with existing values for E. ringens in Perú but are lower than those published for the same species in Chile and from other members of the Engraulis genus. Results reported here can be used for biomass estimation during periods not covered by systematic surveys, helping to achieve near-real time monitoring of stocks.

尽管渔船在过去二十年中被用作机会主义的科学平台，但基于行业收集数据的目标强度（TS）研究仍然很少。在这里，我们根据安装在“Maru”号围网渔船上的120 kHz simmrad ES60商用回声测深仪于2017年5月至7月在中北部种群区捕捞作业期间记录的数据，对秘鲁凤尾鱼（engrulis ringens）进行了现场TS估计。用曲线拟合的方法从汇总数据中估计TS-length (L)关系（TS=a Log10 (L)+b，当a= 20时，b= b20）。研究了深度(Z)对TS的影响。10-16.5 cm个体的TS平均值为- 54.2 dB（±0.2 dB），对应的a、b和b20值分别为22.2、- 79.5 dB和- 77 dB。TS与深度有很强的相关性，遵循波伊耳定律：TS= 20Log10(L)-6.4Log10(1-Z/10)-73.3 dB （r2=0.8）。我们的TS和b20估计值与Perú的现有值一致，但低于智利公布的同一物种和其他Engraulis属成员的估计值。这里报告的结果可用于系统调查未涵盖期间的生物量估计，有助于实现对种群的近实时监测。

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引用次数: 0

New trophic insights associated with the return of a top predator, bluefin tuna, to Skagerrak and the Sound 与顶级捕食者蓝鳍金枪鱼回归斯卡格拉克和海湾有关的新的营养见解

IF 2.3 2区农林科学 Q2 FISHERIES

Fisheries Research

Pub Date : 2025-11-01 Epub Date: 2025-09-12 DOI: 10.1016/j.fishres.2025.107501

Gustav Hellström , Kim Birnie-Gauvin , Petter Lundberg , William Jaktén Langert , Kristi Källo , Lene K. Sortland , Brian R. MacKenzie , Jose Luis Varela , Anders Koed , Einar Eg Nielsen , Andreas Sundelöf , Hege Sande , Maria Overgård , Henrik Baktoft , Kim Aarestrup , Tomas Brodin

This study examines the dietary composition of the recently reoccurring Atlantic bluefin tuna (ABFT, Thunnus thynnus) in the Skagerrak-Kattegat-Sound area of the North-East Atlantic. We analysed the stomach contents of 44 ABFT, with lengths between 232 and 295 cm (CFL), captured in August and September annually from 2020 to 2022 via rod-and-reel fishing. Our analysis identified 19 species of teleost fish, four types of squid, and one crab species, although the diet was dominated by pelagic schooling fish such as garfish (percentage of index of relative abundance (%IRI) = 22.5), herring (%IRI = 6.8), mackerel (%IRI = 6.8), and various demersal gadoid species (combined %IRI = 42). Regional variation in dietary composition between Skagerrak and the Sound indicates that ABFT exhibit foraging flexibility, primarily targeting locally abundant, energy-rich schooling fish, while occasionally consuming other prey. The prevalence of garfish in the diet, which is neither commercially targeted nor managed or regulated, highlights the importance of maintaining healthy stocks of this species for supporting the continuous return of ABFT to the area.

本研究调查了最近在东北大西洋的斯卡格拉克-卡特加特海峡地区重新出现的大西洋蓝鳍金枪鱼（ABFT, Thunnus thynnus）的饮食组成。我们分析了44条ABFT的胃内容物，长度在232至295 cm （CFL）之间，从2020年到2022年，每年8月和9月通过鱼竿和卷轴捕鱼捕获。我们的分析发现了19种硬骨鱼，4种鱿鱼和1种螃蟹，尽管饮食中主要是远洋洄游鱼类，如garfish（相对丰度指数百分比(%IRI) = 22.5），鲱鱼（%IRI = 6.8），鲭鱼（%IRI = 6.8）和各种底栖类（总%IRI = 42）。Skagerrak和Sound之间饮食组成的区域差异表明ABFT表现出觅食的灵活性，主要针对当地丰富，能量丰富的鱼群，偶尔也会消耗其他猎物。饮食中普遍存在的garfish，既没有商业目标，也没有管理或管制，突出了维持该物种健康种群的重要性，以支持该地区ABFT的持续回归。

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引用次数: 0