المؤلفون: Macé, Bastien, Mouillot, David, Dalongeville, Alicia, Bruno, Morgane, Deter, Julie, Varenne, Alix, Gudefin, Anaïs, Boissery, Pierre, Manel, Stéphanie

المصدر: Molecular Ecology; Jun2024, Vol. 33 Issue 12, p1-17, 17p

مصطلحات موضوعية: MARINE parks & reserves, HARBORS, GENETIC barcoding, MARINE biodiversity, RARE fishes, FOSSIL microorganisms, COASTS

مستخلص: Coastal areas host a major part of marine biodiversity but are seriously threatened by ever‐increasing human pressures. Transforming natural coastlines into urban seascapes through habitat artificialization may result in loss of biodiversity and key ecosystem functions. Yet, the extent to which seaports differ from nearby natural habitats and marine reserves across the whole Tree of Life is still unknown. This study aimed to assess the level of α and β‐diversity between seaports and reserves, and whether these biodiversity patterns are conserved across taxa and evolutionary lineages. For that, we used environmental DNA (eDNA) metabarcoding to survey six seaports on the French Mediterranean coast and four strictly no‐take marine reserves nearby. By targeting four different groups—prokaryotes, eukaryotes, metazoans and fish—with appropriate markers, we provide a holistic view of biodiversity on contrasted habitats. In the absence of comprehensive reference databases, we used bioinformatic pipelines to gather similar sequences into molecular operational taxonomic units (MOTUs). In contrast to our expectations, we obtained no difference in MOTU richness (α‐diversity) between habitats except for prokaryotes and threatened fishes with higher diversity in reserves than in seaports. However, we observed a marked dissimilarity (β‐diversity) between seaports and reserves for all taxa. Surprisingly, this biodiversity signature of seaports was preserved across the Tree of Life, up to the order. This result reveals that seaports and nearby marine reserves share few taxa and evolutionary lineages along urbanized coasts and suggests major differences in terms of ecosystem functioning between both habitats. [ABSTRACT FROM AUTHOR]

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المؤلفون: Wolnicki, Jacek, Kaczmarczyk, Dariusz, Sikorska, Justyna, Kamiński, Rafał, Osińska, Adriana, Zawrotna, Natalia

المصدر: PLoS ONE; 6/14/2024, Vol. 19 Issue 6, p1-13, 13p

مصطلحات موضوعية: GENETIC variation, RARE fishes, MINNOWS, MICROSATELLITE repeats, GENETIC polymorphisms, FISH populations

مصطلحات جغرافية: POLAND

مستخلص: The lake minnow Eupallasella percnurus is a small leuciscid fish. In Poland, this species has been in a continuous decline since the mid-20th century and is presently considered as a extremely endangered. According to Polish law, E. percnurus is a strictly protected species that requires active conservation measures. In Poland, one the most common and effective measure of active protection E. percnurus is initiation of new populations. For this purpose, in 2004–2012, juvenile individuals originating from aquaculture conditions were translocated to group of isolated water bodies not inhabited by this species. The juveniles were offspring of parental fish belonging to the same local population, which is extinct at present. Five of those attempts were successful. The aim of the present study was to assess the genetic variation in a group new populations and compare genetic variation indicators with 13 old populations that had existed for decades. The polymorphism of 13 microsatellite markers was investigated, significance of differences in the genetic variation indicators between the groups were tested using a one-way analysis of variance (ANOVA). The mean values of all summary statistics under study, i.e. observed heterozygosity, expected heterozygosity and the total number of alleles, were higher in the group of new populations compared to almost all old ones. A similar dependence was found for Garza—Williamson M values, where the mean for the group of new populations was higher than in almost all old populations. Our results indicate that all recently established E. percnurus populations have not yet experienced any extensive founder effects or bottlenecks. They have preserved a large part of the genetic variability typical of their maternal population, which might also have been relatively high. This feature of new populations, may give them a relatively high ability to adapt to changing environments in the future. [ABSTRACT FROM AUTHOR]

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المؤلفون: Fuzetti, Thomaz Stefani, Charvet, Patricia, Wosnick, Natascha

المصدر: Fisheries Management & Ecology; Jun2024, Vol. 31 Issue 3, p1-8, 8p

مصطلحات موضوعية: FISHING, FISHING surveys, RARE fishes, MARINE parks & reserves, RESEARCH personnel, SOCIAL media

مصطلحات جغرافية: BRAZIL

مستخلص: We comprehensively assessed marine recreational fishing of threatened guitarfishes (Pseudobatos percellens, Pseudobatos horkelii, and Zapteryx brevirostris) in Southern and Southeastern regions of Brazil. A dual‐method approach integrated social media reports and in‐person interviews to explore practices, challenges, and conservation implications of recreational fishing for these species. Seasonal capture of guitarfishes required the promotion of catch‐and‐release, especially during gestational periods, and the development of best angling practices manuals and accessible identification guides. With a focus on land‐based activities and engagement with fishers, our findings underscored the importance of collaboration among researchers, recreational fishers, and conservationists to map and monitor recreational capture and contribute to guitarfish research and conservation. [ABSTRACT FROM AUTHOR]

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المؤلفون: Polansky, Leo, Mitchell, Lara, Nobriga, Matthew L.

المصدر: Conservation Science & Practice; May2024, Vol. 6 Issue 5, p1-14, 14p

مصطلحات موضوعية: POPULATION viability analysis, FRESHWATER habitats, RARE fishes, ANIMAL life cycles, CLIMATE change, WILDLIFE conservation, SMELL

مصطلحات جغرافية: SAN Francisco (Calif.), CALIFORNIA

مستخلص: Identifying the most important factors affecting population growth in animal life cycles is an important tool of species conservation. Delta Smelt (Hypomesus transpacificus), an annual fish endemic to the San Francisco Estuary in California (USA), has been provided legal protection since 1993 but 30 years later exists in a conservation‐reliant state on the brink of extinction. Despite considerable controversies about what factors are most responsible for the species' decline, no population growth rate sensitivity comparisons between the most important factors regulating growth have been done. Nor has anyone attempted to quantitatively identify habitat conditions needed to support positive population growth. We developed a set of stage‐structured population models to link habitat indices regulating recruitment of new generations of fish as they metamorphosed into juveniles and the subsequent survival of those fish over several seasons until they reached adulthood. These models are used to quantify drivers of growth rate variation over 30 years. Several complimentary sensitivity analyses indicated freshwater outflow to the estuary during summer had the largest potential to change population growth. Multiple habitat metrics (e.g., food availability, temperature) influencing recruitment and life stage specific survival rates across different seasons interacted in nonlinear ways to determine habitat conditions and water management targets associated with positive population growth. We discuss the implications for freshwater management, Delta Smelt conservation, and the challenges climate change poses for co‐implementation of these two societal priorities. [ABSTRACT FROM AUTHOR]

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المؤلفون: Gilligan-Lunda, Erin K., Duarte, Adam, Peterson, James T.

المصدر: Canadian Journal of Fisheries & Aquatic Sciences; 2024, Vol. 81 Issue 5, p508-524, 17p

مصطلحات موضوعية: STURGEONS, WILDLIFE conservation, RARE fishes, ENDANGERED species, WATER hardness, KNOWLEDGE gap theory

مصطلحات جغرافية: NORTH America

مستخلص: Sturgeons are among the most endangered fishes in the world. Identifying habitat use characteristics to inform restoration projects is crucial for recovery. However, small sample sizes, inadequate replication of studies, and limited spatial extents complicate our ability to effectively apply the findings of single studies to endangered species conservation across the larger riverscape. We synthesized information from amphidromous and anadromous sturgeons in North America to identify species-specific knowledge gaps and conduct a quantitative comparison of species–habitat relationships. We provided a qualitative summary of substrate use and synthesized estimates of depth and velocity during spawning and non-spawning activity. Generalized patterns among species were identified, such as spawning in fast water on hard substrate and then using slow water with soft substrate areas when not spawning. We noted species-specific variability during spawning that may be attributed to historical maximum length, egg characteristics, and watershed features. This study provides some of the first estimates of habitat use that can be adapted for many populations. Results can contribute to empirically grounded decision-support tools used to prioritize information needs for recovery. [ABSTRACT FROM AUTHOR]

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المؤلفون: Rood, Stewart B., Hoffman, Gregory C., Merz, Norm, Anders, Paul, Benjankar, Rohan, Burke, Michael, Egger, Gregory, Polzin, Mary Louise, Soults, Scott

المصدر: River Research & Applications; May2024, Vol. 40 Issue 4, p587-598, 12p

مصطلحات موضوعية: RARE fishes, STREAMFLOW, RIPARIAN plants, CANADA-United States relations, STREAM channelization, WATERSHED management, SUMMER, RIPARIAN areas

الشركة/الكيان: U.S. Fish & Wildlife Service

مستخلص: Like most rivers worldwide, the transboundary North American Kootenay/i River has experienced multiple impacts including watershed developments, river channelization, and floodplain clearing, draining, and diking. Construction of Libby Dam was authorized by the 1964 Columbia River Treaty (CRT) between the United States and Canada, and in 1975 began regulating downstream flows for flood risk management and hydropower generation. Following cumulative impacts, the endemic Kootenai River White Sturgeon population collapsed and was designated as endangered in 1994 (U.S. Endangered Species Act). Subsequent Biological Opinions from the U.S. Fish and Wildlife Service prescribed Libby Dam operations to provide springtime flow pulses for sturgeon spawning. These provided the unanticipated benefit of substantial seedling recruitment of native and introduced riparian cottonwoods and willows. The regulated flow regime was further adaptively managed to provide a more normative (natural) regime, to balance ecological functions with flood risk management and hydropower generation. The broadened ecological considerations would be consistent with the proposed priorities for the modernization of the international CRT. The observed responses revealed that (1) diverse aquatic and riparian organisms are dependent on common river flow characteristics; (2) a normalized flow regime provided substantial ecological benefits; and (3) due to multiple influences, hybrid ecosystems develop along regulated rivers, with a blending of natural and altered processes and communities. For other regulated rivers, we recommend that (1) high springtime flows be allowed, as feasible; (2) followed by the gradual post‐peak recession; and (3) the maintenance of sufficient flows through the warm and dry interval of mid to late summer. [ABSTRACT FROM AUTHOR]

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المؤلفون: Wu, Jinping, Xiong, Wei, Liu, Wei, Wu, Jinming, Ruan, Rui, Fu, Peng, Wang, Yuqi, Liu, Yuan, Leng, Xiaoqian, Li, Pengcheng, Zhong, Jia, Zhang, Chuang, Du, Hao

المصدر: Antioxidants; Apr2024, Vol. 13 Issue 4, p421, 15p

مصطلحات موضوعية: UNSATURATED fatty acids, IMMUNOGLOBULIN M, OXIDANT status, ACIPENSER, LDL cholesterol, RARE fishes

مستخلص: Currently, the effects of dietary levels of n-3 highly unsaturated fatty acids (HUFAs) on the growth performance, antioxidant capacity, immunity, and serum oxylipin profiles of female F2-generation Yangtze sturgeon remain unknown. A total of 75 Yangtze sturgeons, an endangered freshwater fish species, with an average body weight of 3.60 ± 0.83 kg, were randomly allocated to 15 concrete pools, with each dietary group represented by 5 fish per pool. The fish were fed five different experimental diets containing various levels of n-3 HUFAs (0.5%, 1.0%, 1.5%, 2.0%, and 2.4%). After a feeding period of 5 months, no significant differences in the growth performances of the fish were observed among the five dietary groups (p > 0.05). However, we did note that the serum levels of low-density lipoprotein cholesterol (LDL-C), triglycerides (TGs), and total cholesterol (TCHO) exhibited a marked increase in the fish that consumed higher dietary n-3 HUFA levels (p < 0.05). Conversely, alkaline phosphatase (ALP) activities showed a notable decrease as dietary n-3 HUFA levels increased (p < 0.05). Serum antioxidant indices, such as the activity levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), were significantly higher in the 2.4% HUFA group compared to the 0.5% HUFA group. Additionally, muscle antioxidant indices, including total antioxidant capacity (T-AOC), catalase (CAT), and SOD activity, exhibited notable increases as dietary n-3 HUFA levels increased (p < 0.05). Furthermore, there was a decrease in malondialdehyde (MDA) levels as dietary n-3 HUFA levels increased (p < 0.05). In relation to immune indices, only serum immunoglobulin M (IgM) and muscle complement 3 (C3) were found to be influenced by dietary n-3 HUFA levels (p < 0.05). A total of 80 oxylipins were quantified, and our subsequent K-means cluster analysis resulted in the classification of 62 oxylipins into 10 subclasses. Among the different n-3 HUFA diets, a total of 14 differential oxylipins were identified in the sera. These findings demonstrate that dietary supplementation with n-3 HUFAs exceeding a 1.0% level can enhance antioxidant capacity and regulate serum lipid metabolism, potentially through modulation of oxylipins derived from ARA, DHA, and EPA. These insights provide novel perspectives on the mechanisms underlying these observations. [ABSTRACT FROM AUTHOR]

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المؤلفون: Janhunen, Matti, Eronen, Aslak, Kekäläinen, Jukka, Primmer, Craig R., Donner, Iikki, Hyvärinen, Pekka, Huuskonen, Hannu, Kortet, Raine

المصدر: Evolutionary Applications; Apr2024, Vol. 17 Issue 4, p1-14, 14p

مصطلحات موضوعية: LAKE trout, GENOTYPE-environment interaction, HATCHERY fishes, RARE fishes, GENETIC correlations, SURVIVAL analysis (Biometry), ATLANTIC salmon

مستخلص: Endangered wild fish populations are commonly supported by hatchery propagation. However, hatchery‐reared fish experience very different selective pressures compared to their wild counterparts, potentially causing genotype‐by‐environment interactions (G × E) in essential fitness traits. We experimentally studied early selection in a critically endangered landlocked Atlantic salmon population, first from fertilization to the swim‐up stage in a common hatchery setting, and thereafter until the age of 5 months in two contrasting rearing environments. Swim‐up progeny were moved either to standard indoor hatchery tanks involving conventional husbandry or to seminatural outdoor channels providing only natural food. After the first summer, sampled survivors were assigned to their families by genotyping. Early survival until the swim‐up stage was mostly determined by maternal effects, but also involved significant variation due to sires and full‐sib families (potential genetic effects). High on‐growing survival in hatchery tanks (88.7%) maintained a more even distribution among families (relative share 1.5%–4.2%) than the seminatural environment (0.0%–5.4%). This heterogeneity was mostly maternal, whereas no independent paternal effect occurred. Heritability estimates were high for body size traits in both environments (0.62–0.69). Genetic correlations between the environments were significantly positive for body size traits (0.67–0.69), and high body condition in hatchery was also genetically linked to rapid growth in the seminatural environment (0.54). Additive and phenotypic growth variation increased in the seminatural environment, but scaling effects probably played a less significant role for G × E, compared to re‐ranking of genotypes. Our results suggest that not only maternal effects, but also genetic effects, direct selection according to the environmental conditions experienced. Consistently high genetic variation in growth implies that, despite its low overall genetic diversity and long history in captive rearing (>50 years), this landlocked Atlantic salmon population still possesses adaptive potential for response to change from hatchery rearing back to more natural conditions. [ABSTRACT FROM AUTHOR]

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المؤلفون: Pavlova, Alexandra, Schneller, Nadja M., Lintermans, Mark, Beitzel, Matt, Robledo‐Ruiz, Diana A., Sunnucks, Paul

المصدر: Evolutionary Applications; Apr2024, Vol. 17 Issue 4, p1-20, 20p

مصطلحات موضوعية: INBREEDING, RARE fishes, FRESHWATER fishes, MATING grounds, STREAMFLOW, ANIMAL populations, GENETIC variation

مستخلص: Augmenting depleted genetic diversity can improve the fitness and evolutionary potential of wildlife populations, but developing effective management approaches requires genetically monitored test cases. One such case is the small, isolated and inbred Cotter River population of an endangered Australian freshwater fish, the Macquarie perch Macquaria australasica, which over 3 years (2017–2019) received 71 translocated migrants from a closely related, genetically more diverse population. We used genetic monitoring to test whether immigrants bred, interbred with local fish and augmented population genetic diversity. We also investigated whether levels of river flow affected recruitment, inbreeding depression and juvenile dispersal. Fish length was used to estimate the age, birth year cohort and growth of 524 individuals born between 2016 and 2020 under variable flow conditions. DArT genome‐wide genotypes were used to assess individual ancestry, heterozygosity, short‐term effective population size and identify parent‐offspring and full‐sibling families. Of 442 individuals born after translocations commenced, only two (0.45%) were of mixed ancestry; these were half‐sibs with one translocated parent in common. Numbers of breeders and genetic diversity for five birth year cohorts of the Cotter River fish were low, especially in low‐flow years. Additionally, individuals born in the year of lowest flow evidently suffered from inbreeding depression for juvenile growth. The year of highest flow was associated with the largest number of breeders, lowest inbreeding in the offspring and greatest juvenile dispersal distances. Genetic diversity decreased in the upstream direction, flagging restricted access of breeders to the most upstream breeding sites, exacerbated by low river flow. Our results suggest that the effectiveness of translocations could be increased by focussing on upstream sites and moving more individuals per year; using riverine sources should be considered. Our results indicate that river flow sufficient to facilitate fish movement through the system would increase the number of breeders, promote individuals' growth, reduce inbreeding depression and promote genetic rescue. [ABSTRACT FROM AUTHOR]

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المؤلفون: Bessell, Tyson J., Stuart‐Smith, Rick D., Johnson, Olivia J., Barrett, Neville S., Lynch, Tim P., Trotter, Andrew J., Stuart‐Smith, Jemina

المصدر: Journal of Fish Biology; Apr2024, Vol. 104 Issue 4, p1122-1135, 14p

مصطلحات موضوعية: LIFE history theory, RARE fishes, PARAMETERS (Statistics), MARINE fishes, SIZE of fishes, CENSUS, FISH populations

مصطلحات جغرافية: TASMANIA

الشركة/الكيان: INTERNATIONAL Union for Conservation of Nature & Natural Resources

مستخلص: Population estimates are required for effective conservation of many rare marine species, but can be difficult to obtain. The critically endangered red handfish (Thymichthys politus) is a coastal anglerfish known only from two fragmented populations in southeast Tasmania, Australia. It is at a high risk of extinction due to low numbers, loss of habitat, and the impacts of climate change. To aid conservation efforts, we provide the first empirical population size estimates of red handfish and investigate other important aspects of the species' life history, such as growth, habitat association, and movement. We surveyed both red handfish local populations via underwater visual census on scuba over 3 years and used photographic mark‐recapture techniques to estimate biological parameters. In 2020, the local adult population size was estimated to be 94 (95% confidence interval [CI] 40–231) adults at one site, and 7 (95% CI 5–10) at the other site, suggesting an estimated global population of 101 adults. Movement of individuals was extremely limited at 48.5 m (± 77.7 S.D.) per year. We also found evidence of declining fish density, a declining proportion of juveniles, and increasing average fish size during the study. These results provide a serious warning that red handfish are likely sliding toward extinction, and highlight the urgent need to expand efforts for ex situ captive breeding to bolster numbers in the wild and maintain captive insurance populations, and to protect vital habitat to safeguard the species' ongoing survival in the wild. [ABSTRACT FROM AUTHOR]

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