Management of a highly unlikely native fish: The case of arctic charr Salvelinus alpinus from the Southern Alps

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Eroding diversity away: Impacts of a tetrapod breakwater on a subtropical coral reef

1. Artificial barriers for coastal protection have been deployed across numerous tropical and subtropical islands in the Pacific, including Okinawa Island, southern Japan, where artificial defences have been installed along a large part of the coastline.
2. Although artificial barriers can lead to beach narrowing or loss and can exacerbate erosion, their effects on coral reef ecosystems remain understudied.
3. This study investigated the impact of a tetrapod breakwater in Ogimi Village, Okinawa Island, Japan, comparing the area affected by the presence of the barrier with a nearby natural coastline, and examining differences in physical parameters (depth profiles, sediment granulometry, and erosion on plaster balls) and benthic community composition.
4. Significant differences in depth profiles, sediment granulometry, and erosion were found, suggestive of alterations in water energy levels (lower than controls on the landward side of the barrier, and higher on the seaward side).
5. The benthic community was also clearly affected, with almost no living corals growing over the blocks or in their proximity.
6. Overall, the data show how breakwaters can affect the physical environment and benthic communities in a subtropical coral reef ecosystem, with negative consequences for coral survival.

     

Application of extinction risk and conservation criteria for assessing fish species in the lower La Plata River basin,South America

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Seasonal and spatial bank habitat use by fish in highly altered rivers – a comparison of four different restoration measures

Pander J, Geist J. Seasonal and spatial bank habitat use by fish in highly altered rivers – a comparison of four different restoration measures.
Ecology of Freshwater Fish 2010: 19: 127–138. © 2009 John Wiley & Sons A/S
Abstract –  River regulations have resulted in substantial modifications of the characteristics and the diversity of stream ecosystems. Fish habitat use in the context of species life histories and temporal habitat dynamics are crucial for the development of sustainable measures of habitat restoration in degraded rivers. The objective of this study was to compare the effects of introducing four different in-stream structures (bank ripp-rapp, benched bank ripp-rapp, successively grown riparian wood and artificial dead wood, nine replicates each) on the seasonal fish community distribution in a heavily modified stream ecosystem. Species richness and diversity, fish biomass and density showed strong variation (i) between habitat types, (ii) among replicates of the same habitat type, and (iii) in different seasons. The current low abundance of historical widespread rheophilic and migratory fish species in the study stream suggests that technical bank habitat restoration measures are only of limited use for the restoration of highly specialised target species in conservation such as Barbus barbus and Chondrostoma nasus . However, introduction of particular artificial stream structures (in particular of artificial dead-wood fascines) was found to concentrate biomass and density of none-specialised fish species like Squalius cephalus , Alburnus alburnus , Gobio gobio or Rutilus rutilus .     

Non-native fish in the fresh waters of Portugal, Azores and Madeira Islands: a growing threat to aquatic biodiversity

Abstract  Portugal, the Azores, and Madeira had a combined total of twenty six non-native fish species introductions, with the mainland having the highest number (twenty three), followed by the Azores with ten and Madeira with two records. Fifteen of these species established in Portugal, six in the Azores and one in Madeira. The oldest known introduction (1792) was goldfish, Carassius auratus (L.), while the newest (2005) was tinfoil barb, Barbonymus schwanenfeldii (Bleeker). Ten species had been introduced in Portugal by the beginning of 20th century, but the rate of introduction continues to increase, with four species introduced since 2000. In mainland Portugal, the Douro, the Tejo and the Guadiana drainages had the highest number of introduction records, while the Lima and the Mira drainages had the fewest. Management measures are offered to reduce current rate of fish introductions in Portuguese watersheds.     

Freshwater fishes of Southeast Asia: potential for the aquarium fish trade and conservation issues

SoutheastAsia is an area rich in biodiversity, with a high degree ofendemism in both flora and fauna. Many freshwater fish specieshave been exploited for the ornamental fish trade. As thepopulation in South East Asia increases, vast tracts of forestsare cleared for agricultural, industrial and urbanizationpurposes. To conserve and sustainably exploit the wild fishpopulation, measures should be adopted to protect this naturalresource. Already, several ornamental species have been severelyoverexploited, e.g. bala shark (Balantiocheilos melanopterus),pygmy loach (Botia sidthimunki) and arowana (Scleropagesformosus), but the extirpation of local populations occurs formany reasons, including deforestation, and not just because offishing for the trade. There are also still many species thathave great ornamental fish potential. Wild fish species have alsobeen successfully bred in captivity and conserved, e.g. tigerbarb (Puntius tetrazona), bala shark, pygmy loach and arowana.Other methods of conservation include public education, leavingpristine forests intact and reforestation. The aquarium trade ofthe bala shark, harlequin rasbora (Rasbora heteromorpha), clownloach (Botia macracanthus), arowana and sawfish (Pristismicrodon) is discussed     

Impacts of stock enhancement strategies on the effective population size of Murray cod,Maccullochella peelii,a threatened Australian fish

Abstract Murray cod, Maccullochella peelii (Mitchell) is an iconic Australian species endemic to the Murray‐Darling Basin (MDB) of inland south‐eastern Australia. Murray cod has been a valuable food source and supported a large commercial fishery throughout much of the 20th century. Over‐fishing and habitat destruction have resulted in significant declines in Murray cod populations throughout much of its range. Since the early 1980s, large numbers of Murray cod have been stocked into waterways to support both recreational fishing and conservation efforts. In this study, the likely impacts of past and current stocking practices on genetic diversity of Murray cod were modelled and new strategies to maximise genetic diversity in stocked populations are explored. The results suggest that a large, well‐managed breeding and stocking programme could help maintain genetic diversity of Murray cod across the MDB. In catchments within the MDB where the effective population size is very small, a well‐designed stocking programme, following strict guidelines for numbers of families reared and number of individuals maintained per family, could increase genetic diversity in a few generations.     

广东深圳大鹏半岛海域秋季渔业资源群落结构分析

为探究深圳大鹏半岛沿岸海域渔业资源承载力情况,文章参考《资源环境承载能力监测预警技术方法(试行)》和国内外渔业资源承载力评价方法,结合大鹏半岛沿岸海域实际情况,构建了大鹏半岛沿岸海域渔业资源承载力评价指标体系。基于2012—2016年每年秋季大鹏半岛沿岸海域渔业资源监测调查数据,采用2016年数据与近3年(2013—2015年)数据比较、2016年数据与近4年(2012—2015年)数据比较两种方法,对大鹏半岛沿岸海域渔业资源承载力进行评估。结果表明,两种方法所得结果一致,均为大鹏半岛沿岸海域游泳动物指数呈下降趋势、鱼卵仔稚鱼指数显著下降,渔业资源承载力已临界超载。建议进一步加强海域渔业资源监测调查和渔业资源承载力评价预警,为推进渔业资源修复保护和增殖养护提供技术支持。

     

Multiple metrics provide context for the distribution of a highly mobile fish predator,the blue catfish

Data sets with increased spatial and temporal resolution can help researchers and resource managers quantify representative distributional patterns of mobile sportfish. In this research, first, we illustrate patterns of sportfish distribution using individual (percent of population, residence time, number of movements) and combined distributional metrics. Second, we apply these metrics to one highly mobile fish species, the blue catfish (Ictalurus furcatus), across a range of spatial (whole reservoir, region, site) and temporal (year, month, diel period) scales. Specifically, we tracked 123 acoustically tagged blue catfish with a 20‐receiver array in Milford Reservoir, KS, USA. When we integrated metrics, four site‐specific distributional patterns emerged: (a) a large, active multi‐site fish aggregation, (b) localised site fidelity, (c) transitional sites and (d) rarely used locations. These patterns would not have been detected using a single metric as each measurement revealed a different piece of the distribution story. For example, if we had only quantified percent of population, we could identify fish location, but not whether individual fish spent time at a location or were just passing through. Our examination of multiple scales also provided a novel context for interpreting site‐specific patterns. As an illustration of this insight, using conventional approaches, we would have observed heterogeneity, but we would not have detected fish aggregations, in which individual fish either remained or repeatedly returned to a site. In summary, our results show the advantage of setting the entire ecosystem as the study boundary to integrate multiple responses using a spatially and temporally extensive data set.     

Regional population genetics and global phylogeography of the endangered highly migratory shark Lamna nasus: Implications for fishery management and conservation

1. The porbeagle shark Lamna nasus is a large highly migratory shark distributed in cold and temperate marine waters of the North Atlantic and Southern Hemisphere (SH). According to the International Union for Conservation of Nature, the porbeagle is assessed globally as Vulnerable and regionally as Critically Endangered in the North Atlantic and the Mediterranean Sea. This study explored, for the first time, the population genetics of L. nasus at a regional (south-east Pacific Ocean) and global scale.
2. In this study, the null hypotheses of no genetic discontinuities among populations (i) within the SH, and (ii) between the SH and Northern Hemisphere (NH) were tested. Also, the demographic history of L. nasus in different ocean basins was assessed. Two mitochondrial markers (Control Region [CR] and cox1) well suited for population genetics inferences in sharks were used.
3. Spatial–genetic analyses suggested two genetic clusters co-occurring in the south-eastern Pacific Ocean. A two-way ANOVA using the cox1 but not the CR mtDNA fragment detected an effect of genetic identity on shark body size. Phylogeographic analyses, haplotype networks, and analyses of molecular variance demonstrated genetic differences between populations from the NH and SH but not among populations in the SH.
4. Migration estimates indicated limited current maternal gene flow between the two hemispheres but high gene flow within hemispheres. Two well-defined haplotype groups with star-like shapes inhabited all ocean basins in the SH. These results could reflect a historical scenario of reproductive isolation and more recent mixture among previously isolated populations in the SH. A Bayesian skyline plot analysis indicated sudden population expansion in the SH occurring ~100–125 kya.
5. This study highlights the need for additional studies focusing on the population genomics (using nuclear markers, i.e. single nucleotide polymorphisms) and the general biology of L. nasus to explore the existence of genetically dissimilar populations in the SH. Such studies will help implementing efficient genetic monitoring programmes.

     

The critical importance of an undammed river segment to the reproductive cycle of a migratory Neotropical fish

Biotelemetry, ichthyoplankton and genetic data can provide detailed information about the migratory dynamics and reproductive cycle of freshwater fishes. However, few studies have combined these techniques in Neotropical systems. The objective of this study was to examine the migratory and reproductive dynamics of Prochilodus costatus in the São Francisco River watershed, south‐east Brazil, by comparing the ecological importance of two rivers to the species, an undammed segment of the São Francisco River and a dammed segment of one of its main tributaries, the Pará River. In total, 215 fish were radio‐tagged over three years (2014–16). Eggs and larvae were sampled at seven locations and analysed by PCR to identify Prochilodus spp. ichthyoplankton. Most radio‐tagged individuals (97%) used the undammed segment of the São Francisco River as spawning migration route, even those captured and released in the Pará River. Fish migrated to spawn from late September to late November with the arrival of the rains and returned to feeding sites from December to May after spawning. The highest densities of fish eggs and larvae were recorded in the upper reaches of the São Francisco River during months of peak river discharge. Returning fish showed high fidelity to sites occupied before spawning migration. Fish spent roughly 71% of the year at feeding sites, 25% at spawning sites and 4% moving between them. This study provides novel information about the migratory dynamics of Neotropical fishes and underscores the key role of undammed river segments for the conservation of Neotropical migratory fish species.     

Exploring uncertainty in population viability analysis and its implications for the conservation of a freshwater fish

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Effects of fisheries management on fish communities in the floodplain lakes of a Brazilian Amazonian Reserve

Abstract –  We compared fish abundance, diversity and species composition between lakes open (fished) and closed (no-take) to fishing activities in Mamirauá Sustainable Development Reserve in the Central Brazilian Amazon, in order to investigate potential influences of the common-based management. We sampled 1483 fishes from 70 species through gillnet fishing during the low-water season, in seven fished and seven no-take lakes. Contrary to expected, the mean values for abundance, size, diversity and species-richness of fish did not differ between fished and no-take lakes. There was no difference between fished and no-take lakes considering only the abundance of the 14 fish species more intensely targeted by fishermen. However, the abundance of an important commercial fish, the tambaqui ( Colossoma macropomum ) was higher in no-take lakes. Such data from a rapid assessment may be useful to monitor this and other fishery co-management schemes.     

Identifying a suite of surrogate freshwaterscape fish species: a case study of conservation prioritization in Ontario's Far North,Canada

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A review of sawfishes (Pristidae) in the Arabian region: diversity,distribution, and functional extinction of large and historically abundant marine vertebrates

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Impacts of fishing,river flow and connectivity loss on the conservation of a migratory fish population

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Heads you win,tails you lose: Life‐history traits predict invasion and extinction risk of the world's freshwater fishes

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Harbour seal (Phoca vitulina) abundance within the Firth of Tay and Eden Estuary,Scotland: recent trends and extrapolation to extinction

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