Evaluation of management factors affecting the relative success of a Brook Trout eradication program using YY male fish and electrofishing suppression

Removal of non-native fish populations can be crucial to the conservation of native species, but often presents a complex challenge for managers. The goal of Trojan Y chromosome (TYC) programs is to skew the non-native sex ratio until only males remain, leading to eradication. We present results from a simulation model used to explore effects of alternative management approaches on an in-progress mechanical removal and TYC program to eradicate non-native Brook Trout. Simulation results indicated that stocking fingerling YY males (~137 mm) was more effective than stocking catchable-sized YY males (~230 mm), although questions about inter-cohort competition warrant further investigation. Increasing the proportion of mature fingerling YY males reduced treatment time by increasing the number of YY male spawners and increasing density-dependent mortality on young, mature wild Brook Trout. Maximizing the spatial distribution of YY male releases may be crucial to program success but is also dependent upon immediate dispersal movements. Principles derived from our results can be broadly applied to the management of other aquatic invaded systems using TYC programs to eradicate non-native species.

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Advancing improvement in riverine water quality caused a non-native fish species invasion and native fish fauna recovery

Scientific Reports ◽

10.1038/s41598-021-93751-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Łukasz Głowacki ◽

Andrzej Kruk ◽

Tadeusz Penczak

Keyword(s):

Water Quality ◽

Fish Species ◽

Native Species ◽

Interference Competition ◽

Fish Fauna ◽

Species Traits ◽

Native Fish ◽

Biological Degradation ◽

Species Invasion ◽

Prussian Carp

AbstractThe knowledge of biotic and abiotic drivers that put non-native invasive fishes at a disadvantage to native ones is necessary for suppressing invasions, but the knowledge is scarce, particularly when abiotic changes are fast. In this study, we increased this knowledge by an analysis of the biomass of most harmful Prussian carp Carassius gibelio in a river reviving from biological degradation. The species' invasion followed by the invasion's reversal occurred over only two decades and were documented by frequent monitoring of fish biomass and water quality. An initial moderate improvement in water quality was an environmental filter that enabled Prussian carp’s invasion but prevented the expansion of other species. A later substantial improvement stimulated native species’ colonization of the river, and made one rheophil, ide Leuciscus idus, a significant Prussian carp’s replacer. The redundancy analysis (RDA) of the dependence of changes in the biomass of fish species on water quality factors indicated that Prussian carp and ide responded in a significantly opposite way to changes in water quality in the river over the study period. However, the dependence of Prussian carp biomass on ide biomass, as indicated by regression analysis and analysis of species traits, suggests that the ecomorphological similarity of both species might have produced interference competition that contributed to Prussian carp’s decline.

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Facilitating Successful Smart Campus Transitions: A Systems Thinking-SWOT Analysis Approach

Applied Sciences ◽

10.3390/app11052044 ◽

2021 ◽

Vol 11 (5) ◽

pp. 2044

Author(s):

Bankole Awuzie ◽

Alfred Beati Ngowi ◽

Temitope Omotayo ◽

Lovelin Obi ◽

Julius Akotia

Keyword(s):

Systems Thinking ◽

Swot Analysis ◽

Qualitative Content Analysis ◽

Holistic Approach ◽

Education Institution ◽

Factors Affecting ◽

Smart Campus ◽

University Of Technology ◽

Management Approaches ◽

Gap Data

An identification of strengths, weakness, opportunities, and threats (SWOT) factors remains imperative for enabling a successful Smart Campus transition. The absence of a structured approach for analyzing the relationships between these SWOT factors and the influence thereof on Smart Campus transitions negate effective implementation. This study leverages a systems thinking approach to bridge this gap. Data were collected through a stakeholder workshop within a University of Technology case study and analyzed using qualitative content analysis (QCA). This resulted in the establishment of SWOT factors affecting Smart Campus transitions. Systems thinking was utilized to analyze the relationships between these SWOT factors resulting in a causal loop diagram (CLD) highlighting extant interrelationships. A panel of experts drawn from the United Kingdom, New Zealand, and South Africa validated the relationships between the SWOT factors as elucidated in the CLD. Subsequently, a Smart Campus transition framework predicated on the CLD archetypes was developed. The framework provided a holistic approach to understanding the interrelationships between various SWOT factors influencing Smart Campus transitions. This framework remains a valuable tool for facilitating optimal strategic planning and management approaches by policy makers, academics, and implementers within the global Higher Education Institution (HEI) landscape for managing successful Smart Campus transition at the South African University of Technology (SAUoT) and beyond.

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The first unified inventory of non-native fishes of the South Caucasian countries, Armenia, Azerbaijan, and Georgia

Knowledge and Management of Aquatic Ecosystems ◽

10.1051/kmae/2021028 ◽

2021 ◽

pp. 32

Author(s):

Tatia Kuljanishvili ◽

Levan Mumladze ◽

Bella Japoshvili ◽

Namig Mustafayev ◽

Shaig Ibrahimov ◽

...

Keyword(s):

Black Sea ◽

Fish Species ◽

Caspian Sea ◽

Native Species ◽

Biological Diversity ◽

Native Fish ◽

The Black Sea ◽

The South ◽

In The Wild ◽

Native Fishes

The South Caucasus (SC) region is recognized for its high biological diversity and various endemic animal taxa. The area has experienced many fish introductions over the years, but the overall information about non-native fishes in the three SC countries, Armenia, Azerbaijan, and Georgia did not exist. Although these three countries belong to the Kura River drainage, Caspian Sea basin (only the western half of Georgia drains into the Black Sea), the legislative framework for each country regarding introduction of non-native fish species and their treatment is different and poorly developed. The goal of the present study was to make an initial inventory of non-native fish species in the three SC countries, and summarize the existing knowledge as a basis for future risk assessment models and formulation of regional management policies. Here, we present a unified list of 27 non-native species recorded in the wild in Armenia, Azerbaijan, and Georgia. Among these 27 species, eight were translocated from the Black Sea basin to the Caspian Sea basin. Out of these 27 non-native fishes, 15 species have become established (three of them being considered invasive) and six fish species could not survive in the wild.

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Preserving Wildlife: An International Perspective

Pacific Conservation Biology ◽

10.1071/pc010146 ◽

2001 ◽

Vol 7 (2) ◽

pp. 146

Author(s):

Nadia Elizabeth Tapp

Keyword(s):

Wildlife Management ◽

Native Species ◽

Captive Breeding ◽

Management Strategies ◽

Field Studies ◽

Moral Values ◽

International Perspective ◽

Management Approaches ◽

Sport Hunting ◽

Selection Of

PRESERVING Wildlife: An International Perspective is an anthology of twenty papers exploring the issues related to the preservation of wildlife, with an emphasis on related management approaches. This topic is introduced philosophically with a discussion of moral values associated with human activities. Sport hunting, the medical aid of injured wild animals and the manipulation of wildlife during ecological field studies are discussed within this context. The focus then shifts to a selection of wildlife management strategies including habitat protection, captive breeding, culling of non-native species, eco-tourism and marketing of wildlife products.

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What is needed to restore native fishes in Australia’s Murray–Darling Basin?

Marine and Freshwater Research ◽

10.1071/mf20248 ◽

2020 ◽

Vol 71 (11) ◽

pp. 1464

Author(s):

John D. Koehn ◽

Stephen R. Balcombe ◽

Lee J. Baumgartner ◽

Christopher M. Bice ◽

Kate Burndred ◽

...

Keyword(s):

First Nations ◽

Native Species ◽

Cultural Practices ◽

Native Fish ◽

The Past ◽

Murray Darling Basin ◽

Native Fishes ◽

Conservation Concern ◽

First Nations People

The Murray–Darling Basin (MDB) is Australia’s food bowl, contributing 40% of agricultural production and supporting a population of over 4 million people. Historically, the MDB supported a unique native fish community with significant cultural, subsistence, recreational, commercial and ecological values. Approximately one-quarter of the MDB’s native species are endemic. Changes to river flows and habitats have led to a >90% decline in native fish populations over the past 150 years, with almost half the species now of conservation concern. Commercial fisheries have collapsed, and important traditional cultural practices of First Nations People have been weakened. The past 20 years have seen significant advances in the scientific understanding of native fish ecology, the effects of human-related activities and the recovery measures needed. The science is well established, and some robust restoration-enabling policies have been initiated to underpin actions. What is now required is the political vision and commitment to support investment to drive long-term recovery. We present a summary of 30 priority activities urgently needed to restore MDB native fishes.

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Exotic plus native: findings in an unscheduled fish duoculture

Latin American Journal of Aquatic Research ◽

10.3856/vol49-issue4-fulltext-2674 ◽

2021 ◽

Vol 49 (4) ◽

pp. 649-653

Author(s):

David Julián Palma-Cancino ◽

Mao Ernesto Rafael Basto-Rosales ◽

Carlos Alfonso Álvarez-González ◽

Rafael Martínez-García ◽

Daniel Badillo-Zapata ◽

...

Keyword(s):

Native Species ◽

Good Alternative ◽

Native Fish ◽

Sustainable Aquaculture ◽

Feed Conversion ◽

Exotic Fish ◽

Biological Variables ◽

Nile Tilapia Oreochromis Niloticus ◽

Concrete Tank ◽

Feed Conversion Rate

The development of native fish aquaculture represents an important alternative to mitigate ecological displacement generated by exotic fish. The introduction of native fish in polyculture systems with high commercial value fishes has provided a useful strategy for sustainable aquaculture development. The present study aims to provide information on tilapia, as an exotic species, and Dormitator latifrons, as a native species, in a duo culture not programmed as such. Using juveniles of Pacific fat sleeper D. latifrons leftovers from another experiment, we decide to analyze and report the biological feasibility of a duoculture system with this species and Nile tilapia (Oreochromis niloticus). Two hundred fifty organisms of each species were placed for 90 days in a concrete tank with a capacity of 50 m3 to evaluate the compatibility of these species. The biological variables measured were growth, survival, feed conversion rate, and protein efficiency. The findings suggest a good interaction between species, with adequate growths and a survival rate of 98%. No antagonistic behavior was observed during confinement, suggesting the duoculture of these species may represent a good alternative for tropical sustainable aquaculture.

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Coptotermes formosanus (Formosan subterranean termite).

10.1079/cpc.15284.20210099969 ◽

2021 ◽

Author(s):

Gregg Henderson

Keyword(s):

Native Species ◽

Coptotermes Formosanus ◽

Subterranean Termite ◽

Limiting Factor ◽

Port Cities ◽

Factors Affecting ◽

Termite Control ◽

Exotic Pests ◽

The Usa ◽

The 1960S

Abstract C. formosanus is often transported by boats and shipping containers to port cities before being carried further inland via landscape materials such as railroad ties (railway sleepers). This may explain the current C. formosanus distribution in the USA with coastal areas more densely infested than inland areas (Hochmair and Scheffrahn, 2010). Temperature and humidity are primary factors affecting the establishment of C. formosanus, and it is potentially invasive to areas of high humidity approximately 35° north and south of the equator (Su and Tamashiro, 1987). Competition from native species is another limiting factor for many exotic pests, but C. formosanus is more aggressive and is known to out-compete the endemic termites such as Reticulitermes species. Another factor that has allowed the successful establishment and spread of C. formosanus in exotic areas has been the pest control industry's heavy reliance on soil termiticide barriers for subterranean termite control since the 1950s. Numerous studies, using mark-recapture methods, have revealed that a single colony of C. formosanus might contain several million termites that forage up to 100 m in the soil (Lai, 1977; Su and Scheffrahn, 1988). These agree with the results of excavation studies for C. formosanus colonies (Ehrhorn, 1934; King and Spink, 1969). Because of the large colony size, the application of soil termiticides beneath a structure does not usually have a major impact on the overall population, and the surviving colony continues to produce alates that can further infest nearby areas. Once established, C. formosanus has never been completely eradicated from an area. The dependency of soil termiticide barriers as the primary tool for subterranean termite control is probably the main reason for the establishment and spread of C. formosanus from four isolated port cities in the 1960s in the USA to all south-eastern states by 2001.

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Rapid resistance to pesticide control is predicted to evolve in an invasive fish

Scientific Reports ◽

10.1038/s41598-019-54260-5 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Mark R. Christie ◽

Maria S. Sepúlveda ◽

Erin S. Dunlop

Keyword(s):

Genetic Model ◽

Sea Lamprey ◽

Control Agent ◽

Native Fish ◽

Primary Control ◽

Factors Affecting ◽

Natal Homing ◽

Generation Times ◽

Evolution Of Resistance ◽

Near Future

AbstractXenobiotic resistance is commonly found in species with short generation times such as bacteria, annual plants, and insects. Nevertheless, the fundamental evolutionary principles that govern the spread of resistance alleles hold true for species with longer generation times. One such example could occur with sea lamprey (Petromyzon marinus), a parasitic invasive species in the Laurentian Great Lakes that decimated native fish populations prior to its control with the pesticide 3-trifluoromethyl-4-nitrophenol (TFM). Since the 1950s, tributaries have been treated annually with TFM, where treatments effectively remove most, but not all, larval sea lamprey. We developed an eco-genetic model of sea lamprey to examine factors affecting the evolution of resistance and found that resistance alleles rapidly rise to fixation after 40–80 years of treatment, despite the species’ relatively long generation time (4–7 years). The absence of natal homing allows resistant individuals to spread quickly throughout the entire system, but also makes the early detection of resistance challenging. High costs of resistance and density independent reproduction can delay, but not prevent, the onset of resistance. These results illustrate that sea lamprey have the potential to evolve resistance to their primary control agent in the near future, highlighting the urgent need for alternative controls.

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Development of a fish-based index for the assessment of the ecological status of Lake Balaton in the absence of present day reference condition

Knowledge and Management of Aquatic Ecosystems ◽

10.1051/kmae/2020002 ◽

2020 ◽

pp. 11 ◽

Cited By ~ 1

Author(s):

András Specziár ◽

Tibor Erős

Keyword(s):

Native Species ◽

Ecological Status ◽

Fish Fauna ◽

Native Fish ◽

Lake Balaton ◽

Anthropogenic Pressures ◽

Key Species ◽

Good Ecological Status ◽

Electric Fishing

A fish-based index is proposed to indicate the ecological status of Lake Balaton, Hungary in accordance with the standard of the European Water Framework Directive (WFD). The Balaton fish index (BFI) synthetises information of 13 lake-specific fish metrics including gillnetting and electric fishing data of species richness of native assemblages, relative abundance, biomass and age structure of native key species, representation of non-native species and general health status. The main anthropogenic pressures considered were the degradation of littoral habitats, invasion of non-native fish species, eutrophication and fishing/angling including stocking. Ecological quality ratio (EQR) is assessed by relating actual fish assemblage metrics to the supposed undisturbed reference status of Lake Balaton reconstructed by expert judgement based on recent and historic information on the fish fauna and its changes. Values of BFI were consistent and indicated good ecological status of Lake Balaton in the period of 2005–2018. This study provides an example on how an EQR assessment methodology might be established in unique habitats with no possibilities for statistical evaluation of pressure-respond relationships and exact determination of the reference status.

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Reproduction in Brook Trout (Salvelinus fontinalis) Fed Sublethal Concentrations of DDT

Journal of the Fisheries Research Board of Canada ◽

10.1139/f68-164 ◽

1968 ◽

Vol 25 (9) ◽

pp. 1787-1796 ◽

Cited By ~ 53

Author(s):

Kenneth J. Macek

Keyword(s):

Brook Trout ◽

Salvelinus Fontinalis ◽

Wild Fish ◽

Major Portion ◽

Feeding Period ◽

Male Fish ◽

Insecticide Residues ◽

Treated Fish ◽

Sublethal Concentrations ◽

Maximum Utilization

When sexually maturing yearling brook trout were fed for 156 days with DDT at rates that evidently caused no mortality, fish fed at the lower dosages produced more mature ova than untreated fish. Those fed at the highest dosage produced fewer mature ova than untreated fish. The size of the male fish at the end of the feeding period tended to increase according to dosage of DDT. In eggs and sac fry obtained from various mating combinations of gametes from the experimental groups, mortality was with one exception higher when at least one of the gametes came from treated fish than when they both came from untreated fish. A major portion of the mortality of sac fry in groups where the eggs came from treated fish occurred during the 15th week of development. This period coincided with the period of maximum, utilization of yolk fat reported to occur in other salmonid fry, and indicated that insecticide residues in the eggs were released at this time and resulted in the observed mortality. The residue concentrations in the fish at the end of the feeding period were similar to those reported for wild fish.

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