Invasive Smallmouth Bass Research Articles

Development of LAMP primers for rapid detection of invasive smallmouth bass from environmental DNA

Development of LAMP primers for rapid detection of invasive smallmouth bass from environmental DNA

Small mouth, big appetite: diet analysis of invasive smallmouth bass (Micropterus dolomieu) in Cultus Lake, British Columbia

Small mouth, big appetite: diet analysis of invasive smallmouth bass (Micropterus dolomieu) in Cultus Lake, British Columbia

Male guarding behavior and brood predators of invasive Bluegill in a Japanese lake

AbstractObjectiveThe Bluegill Lepomis macrochirus, which utilizes colony spawning, has been introduced globally, and in Japan it is considered one of the worst invasive species. However, a detailed examination of the factors driving male guarding behavior and brood predation in the invaded habitat is lacking. The removal of guarding males, a common management technique in Japan, is thought to be effective in controlling Bluegill. However, the colony spawning strategy may influence the effectiveness of selective male removal through brood protection from neighbor males.MethodsBluegill spawning was studied in Lake Nojiri, Nagano, Japan, using underwater video recording and experimental removal of guarding males.ResultBluegill were found spawning in shallow habitat during June–July, and nests were constructed in loosely aggregated colonies, with many solitary nests. Males utilized a variety of guarding behaviors, such as rim circling and predator chases, as well as paternal investment behaviors, such as tail fanning. Males that preyed upon their own eggs defended their nests less aggressively and invested less time in nourishing behaviors. Removal of guarding males revealed that brood predators were primarily conspecific Bluegill, but other fishes, such as invasive Smallmouth Bass Micropterus dolomieu and Largemouth Bass M. nigricans as well as native Japanese Dace Pseudaspius hakonensis, preyed on broods.ConclusionIn concurrence with the colony spawning theory, nests that were located closer to other nests with active guarding males experienced decreased brood predation and increased predator arrival time after male removal. In addition, nests where males had been guarding more aggressively prior to removal experienced reduced brood predation after male removal. These results provide insights into the factors driving male guarding behavior and brood predation of colony‐spawning Bluegill in an invasive habitat and indicate that the removal of guarding males—a common management strategy in Japan—may have reduced effectiveness due to colony spawning.

Spawning season and nest guarding behavior of invasive smallmouth bass (Micropterus dolomieu) in a Japanese Lake

AbstractSpawning of invasive smallmouth bass (Micropterus dolomieu) was studied in 2020 and 2021, in Lake Nojiri, Nagano, Japan. Male smallmouth bass began nest construction once water temperatures reached 14°C, and eggs progressed to fry dispersal in approximately 2 weeks. The main spawning season was in late May through early June, with a smaller second peak of nests in late June through early July. Nests were constructed primarily under dock cover, and nest size and depth were positively correlated with male body size. Of the nests that received eggs, nearly all progressed successfully to fry dispersal. Time lapse videos of male guarding behavior revealed that as nests progressed, males rotated less and were suspended off the bottom substrate. Similarly, the presence of egg predators was determined by experimental removal of guarding males. Freshwater gobies (Rhinogobius kurodai) were the only egg predators observed and arrived on all nests in the egg stage. However, only a handful of gobies visited each nest, the total number of eggs predated was low, and eggs or alevins in the progressed stage were rarely predated. These results indicate that in Lake Nojiri, smallmouth bass spawning is highly successful and egg predators appear to have minimal effect on egg survival. The stable smallmouth bass fishery without stocking at this lake is likely a product of these favorable spawning conditions. The lack of native egg predators may also be a driving factor in the continued spread of smallmouth bass throughout Japan.

Changes in foraging and predator avoidance behavior of Japanese dace (Pseudaspius hakonensis) to predation risk by invasive smallmouth bass (Micropterus dolomieu) in a Japanese lake

Changes in foraging and predator avoidance behavior of Japanese dace (Pseudaspius hakonensis) to predation risk by invasive smallmouth bass (Micropterus dolomieu) in a Japanese lake

Habitat dependent predation‐competition interaction shifts of invasive smallmouth bass (Micropterus dolomieu) and resident cyprinids in the Chikuma River, Nagano Japan

Habitat use and diet composition of invasive smallmouth bass, Micropterus dolomieu, Japanese dace, Pseudaspius hakonensis, and pale chub, Opsariichthys platypus, were studied for two years in the Middle Chikuma River, Nagano, Japan. Habitat use of dace and chub overlapped both years but showed differences from smallmouth bass. Additionally, smallmouth bass habitat use differed greatly between years, as young smallmouth bass were found in uncharacteristically fast flowing habitat in 2018 and predominantly in more typical slow flowing habitat in 2019. This use of fast flowing habitat in 2018 appears to be influenced by the high overall fish density, especially for smallmouth bass. Diet composition, studied in 2018, overlapped significantly between the three species in riffle habitat and overlap became less significant in run and pool habitat where smallmouth bass fed increasingly on fish prey. We therefore suggest that the interactions between smallmouth bass and dace and chub shift from predominantly predation in slow flowing habitat to resource competition in faster flowing habitat.

Invasion and food habits of invasive smallmouth bass in Shingashi River, Saitama, Japan

Invasion and food habits of invasive smallmouth bass in Shingashi River, Saitama, Japan

Spawning season and nesting habitat of invasive smallmouth bass Micropterus dolomieu in the Chikuma River, Japan

Spawning season and habitat of invasive smallmouth bass were studied for two seasons in the Chikuma River, Nagano, Japan. Smallmouth bass spawning started in early May, when required water temperatures were met, and continued as long as spawning was not disrupted by high water levels. Spawning sites were found in patches throughout the study area that had significantly different physical characteristics than typical stream habitat features. Utilized spawning sites had low current velocity, were relatively shallow, and had pebble-sized substrate. Individual nest variables showed correlation with nesting male size as larger males constructed larger and deeper nests in faster flowing and deeper areas of the river. Nest guarding rates were low while egg presence rates were high compared to the native range, which may indicate that factors such as favorable water levels and water temperature and prevalence of spawning habitat facilitate spawning and the spread of smallmouth bass in the Chikuma River.

Stream drift feeding and microhabitat competition of invasive smallmouth bass Micropterus dolomieu, native Japanese dace Tribolodon hakonensis and pale chub Opsariichthys platypus in the Nogu River, Japan

Foraging behavior and microhabitat use of native Japanese dace, pale chub, and invasive smallmouth bass were studied in the Nogu River, Nagano, Japan. Chub, dace and smallmouth bass all used drift feeding as their dominant foraging behavior. Chub drift fed most frequently, followed by dace, and smallmouth bass drift fed significantly less frequently than both native species. Chub and dace utilized microhabitat that had significantly higher flow velocity than smallmouth bass. However, smaller chub and dace were found in areas with lower flow velocity compared to larger individuals. Prey resource competition between smallmouth bass and native cyprinids, especially smaller individuals, is suspected due to similar feeding methods and microhabitat use.

The ghost of introduction past: Spatial and temporal variability in the genetic diversity of invasive smallmouth bass.

Understanding the demographic history of introduced populations is essential for unravelling their invasive potential and adaptability to a novel environment. To this end, levels of genetic diversity within the native and invasive range of a species are often compared. Most studies, however, focus solely on contemporary samples, relying heavily on the premise that the historic population structure within the native range has been maintained over time. Here, we assess this assumption by conducting a three‐way comparison of the genetic diversity of native (historic and contemporary) and invasive (contemporary) smallmouth bass (Micropterus dolomieu) populations. Analyses of a total of 572 M. dolomieu samples, representing the contemporary invasive South African range, contemporary and historical native USA range (dating back to the 1930s when these fish were first introduced into South Africa), revealed that the historical native range had higher genetic diversity levels when compared to both contemporary native and invasive ranges. These results suggest that both contemporary populations experienced a recent genetic bottleneck. Furthermore, the invasive range displayed significant population structure, whereas both historical and contemporary native US populations revealed higher levels of admixture. Comparison of contemporary and historical samples showed both a historic introduction of M. dolomieu and a more recent introduction, thereby demonstrating that undocumented introductions of this species have occurred. Although multiple introductions might have contributed to the high levels of genetic diversity in the invaded range, we discuss alternative factors that may have been responsible for the elevated levels of genetic diversity and highlight the importance of incorporating historic specimens into demographic analyses.

The trout fishery of the upper Medway watershed, Nova Scotia, 2016-17

During the spring of 2016 and 2017, the Mersey Tobeatic Research Institute (MTRI), in collaboration with the Nova Scotia Department of Fisheries and Aquaculture, conducted an angler creel survey in the Medway Lakes Wilderness Area that is located within the upper Medway watershed. Since 2012, public access to this region was improved to numerous lakes and streams, increasing the risk of overexploitation and the illegal introduction of invasive fish species. The purpose of this study was to assess the current status of the fishery for Brook trout, Salvelinus fontinalis, investigate the possible presence of invasive Smallmouth bass, Micropterus dolomieu, and Chain pickerel, Esox niger, and inform anglers of the effects of invasive species on local biodiversity. Over the course of this two-year study, a total of 264 anglers spent 1017 hours to catch 1279 trout, of which 74% were released. Median length of retained Brook trout was of 25 cm and the maximum length was 43 cm. The majority of the catch was 2+ and 3+ years old. Angler catch rates were similar to nearby Kejimkujik National Park and greater than in the Tangier Grand Lakes Wilderness Area. The study area does not currently appear to be inhabited by invasive fish species. Most of the anglers interviewed lived nearby and had a long history of fishing in the upper Medway watershed. The study provides baseline data from the trout fishery which could be used to evaluate management strategies and future impacts of invasive fish species.

Dynamism in the upstream invasion edge of a freshwater fish exposes range boundary constraints.

Studying the dynamics of species' borders can provide insight into the mechanisms limiting or promoting range expansion in response to environmental change. In the John Day River, Oregon (USA), rising stream temperatures are facilitating the upstream expansion of invasive smallmouth bass Micropterus dolomieu. Here, where smallmouth bass occupy the upstream limit of its thermal tolerance, we explore population structure and seasonal movement patterns to elucidate the environmental conditions and individual traits that define front edge (where individuals reside year-round) and leading edge (where individuals colonize, but may not establish) limits to its upstream distribution. Reporting on a multi-year, spatially extensive riverscape survey, our results show dramatic ebbs and flows of seasonal occupancies due to individual movement with an overall trend of upstream expansion. We revealed distinct front and leading edge invasion extents, each constrained by different ecological conditions. The front edge is largely constrained by the ability for juveniles to survive an overwinter starvation period, whereas the leading edge is associated with adult growth potential and seasonal hydrological conditions. We also found key morphological traits associated with more mobile individuals. By providing mechanistic insight into the factors that promote or limit range expansion of an invasive riverine species, our study enhances the ability to predict future range shifts and provides critical information to managers tasked with restricting further expansion.

Preliminary evaluation of the impact of invasive smallmouth bass Micropterus dolomieu on native fish abundance in the Witte River, Cape Floristic Region, South Africa

The impact of invasive smallmouth bass, Micropterus dolomieu, on the abundance of two native fish species, Breede River redfin, Pseudobarbus burchelli, and Cape kurper, Sandelia capensis, was investigated in the Witte River tributary of the Breede River in South Africa’s Cape Floristic Region (CFR). Native fish density was estimated in five pools and three riffles both above and below a 2 m-high waterfall that acts as a barrier to M. dolomieu. Both native species were relatively abundant (mean ± S.E. fish/100 m2: 152.10 ± 19.16–10.33 ± 6.06) at sites above the waterfall where M. dolomieu was absent, but absent or scarce (0–0.53±0.38 fish/100m2) at sites below it with M. dolomieu. There were no significant differences in measured environmental variables between sites above and below the waterfall, and M. dolomieu is thus implicated as the main factor responsible for the differences in native fish densities. These findings highlight the critical role of waterfalls in excluding non-native fishes from native fish refugia in the CFR.

Stage‐Structured Simulations Suggest That Removing Young of the Year Is an Effective Method for Controlling Invasive Smallmouth Bass

AbstractSmallmouth Bass Micropterus dolomieu is an invasive fish for which few control methods have been developed or tested. Adult removal is most common, but this strategy is labor‐intensive and can result in an increase in population abundance (i.e., overcompensation). Using a stage‐structured matrix model, we tested removal of young of the year as a control method, both alone and in combination with three supplemental removal strategies. Our results suggest that young of the year removal alone does not lead to overcompensation and can be expected to control some populations of Smallmouth Bass in a reasonable timeframe (e.g., 75% reduction in abundance after 10 years at 68% removal). Lower rates of removal of young of the year are required if this method is combined with supplemental removal strategies (especially those that also target immature bass). Where feasible, we recommend that managers include young of the year removal as part of their control plans. Future research should focus on incorporating more biological realism into simulation models and testing this method in the field.Received January 15, 2014; accepted April 24, 2014

Preliminary Evaluation of the Impact of Invasive Smallmouth BassMicropterus dolomieuon Native Fish Abundance in the Witte River, Cape Floristic Region, South Africa

The impact of invasive smallmouth bass, Micropterus dolomieu, on the abundance of two native fish species, Breede River redfin, Pseudobarbus burchelli, and Cape kurper, Sandelia capensis, was investigated in the Witte River tributary of the Breede River in South Africa's Cape Floristic Region (CFR). Native fish density was estimated in five pools and three riffles both above and below a 2 m-high waterfall that acts as a barrier to M. dolomieu. Both native species were relatively abundant (mean ± S.E. fish/100 m2: 152.10 ± 19.16–10.33 ± 6.06) at sites above the waterfall where M. dolomieu was absent, but absent or scarce (0–0.53 ± 0.38 fish/100 m2) at sites below it with M. dolomieu. There were no significant differences in measured environmental variables between sites above and below the waterfall, and M. dolomieu is thus implicated as the main factor responsible for the differences in native fish densities. These findings highlight the critical role of waterfalls in excluding non-native fishes from nati...

Invasive smallmouth bass (Micropterus dolomieu): history, impacts, and control

In this review, we (i) describe smallmouth bass (Micropterus dolomieu Lacepede, 1802) invasions past, present, and future; (ii) summarize the impact that this species can have on native communities; and (iii) describe and discuss various options for control. M. dolomieu are invasive throughout much of the United States, southern portions of Canada, and in countries in Europe, Asia, and Africa. Historically, this species spread via stocking programs intended to improve sport fisheries. Currently, their spread is facilitated by anglers and global climate change. Models predict that M. dolomieu will continue to spread with consequences for native prey fish, sport fish, and food webs through predation, competition, and hybridization. Effective control methods are necessary to mitigate these impacts. Options for M. dolomieu control include biological control, chemical control, environmental manipulation, and physical removal. However, our review of the literature suggests that only a handful of the possible control options have been explored (usually in isolation and with limited success), and that there is a clear need for focused research and informed management. For example, our elasticity analysis of published M. dolomieu matrix population models suggests that M. dolomieu control will be most effective when it targets eggs, larvae, and juveniles. We recommend targeting these life stages by using nest failure as part of an adaptive and integrated pest management approaches that incorporate existing and emerging technologies. However, we also emphasize that M. dolomieu control, where necessary and possible, is more likely to take the form of suppression rather than permanent eradication. Therefore, we also recommend efforts to prevent M. dolomieu (re)introduction.

Prey naivety in the behavioural responses of juvenile Chinook salmon (Oncorhynchus tshawytscha) to an invasive predator

Summary1. Non‐native predators might inflict proportionally higher mortality on prey that have no previous experience of them, compared to species that have coexisted with the predator for some time.2. We tested whether juvenile Chinook salmon (Oncorhynchus tshawytscha) were less able to recognise a non‐native than a native predator, by investigating behavioural responses to the chemical cues of the invasive smallmouth bass (Micropterus dolomieu) and the native northern pikeminnow (Ptychocheilus oregonensis) in both laboratory and field experiments.3. Laboratory results demonstrated strong innate antipredator responses of individual juvenile Chinook salmon to northern pikeminnow; fish spent 70% of time motionless and exhibited 100% greater panic response than in controls. By contrast, antipredator responses to the chemical cues of smallmouth bass did not differ from controls.4. These results were supported by similar differences in recognition of these predator odours by groups of juvenile Chinook salmon in fully natural conditions, though responses reflected a greater range of antipredator behaviours by individuals. In field trials, responses to northern pikeminnow odour resulted in increased flight or absence, reductions in swimming and foraging, and increased time spent near the substratum, compared to smallmouth bass odour.5. Given that survival of juvenile fish is facilitated by predator recognition, our results support the hypothesis that naivety may be an important factor determining the effect of non‐native predators on prey populations. Efforts to manage the effect of native and non‐native predators may benefit by considering complex behavioural interactions, such as these at the individual and group levels.

Invasive crayfish in a high desert river: Implications of concurrent invaders and climate change

No crayfish species are native to the Colorado River Basin (CRB), including the portion of the state of Colorado west of the Continental Divide. Virile crayfish [Orconectes virilis (Hagen, 1870)], a recent invader in the middle Yampa River in northwestern Colorado, displayed an abrupt increase in abundance in the early 2000s, which coincided with a drought, a severe decline in the abundance of smallbodied and juvenile native fishes, and a dramatic increase in the abundance of nonnative smallmouth bass [Micropterus dolomieu (Lacepede, 1802)]. The annual density of virile crayfish was 6.4/m 2 in 2005 and 9.3/m 2 in 2006. The annual biomass density of virile crayfish was 9.0g/m 2 in 2005 and 15.8 g/m 2 in 2006, representing a riverwide biomass of 122 kg/ha, which equaled that of other macroinvertebrates and fish combined (120.7 kg/ha). Efforts to recover and preserve native fishes in the Upper Colorado River Basin (UCRB), particularly in the Yampa River, have been hampered by nonnative predatory fishes, but the implications of crayfish may have been overlooked and underestimated. Stream conditions during the drought apparently facilitated proliferation by virile crayfish in the middle Yampa River, likely contributing to hyperpredation on native fishes by invasive smallmouth bass. This trophic interaction between virile crayfish and smallmouth bass, in conjunction with regional projections for climate change, will likely make efforts to reduce the abundance and negative ecological impact of smallmouth bass in this ecosystem more difficult and costly. Given the nonnative status of all crayfishes in the CRB, and their invasive capacity and potential to negatively reconfigure native lotic food webs, all states in the UCRB should prohibit the importation, movement, sale, possession and stocking of any live crayfish.

The impact of invasive fish and invasive riparian plants on the invertebrate fauna of the Rondegat River, Cape Floristic Region, South Africa

Invasive fish and plants are widespread in the rivers and riparian zones of the Cape Floristic Region of South Africa and represent potential threats to the highly endemic freshwater fauna. We investigated the impact of invasive smallmouth bass (Micropterus dolomieu) and black wattle (Acacia mearnsii) on assemblages of macroinvertebrates and fish in a cobble-bed foothill river, the Rondegat River, in the Cederberg mountains, by sampling from sites representing four invasion conditions: no invasion; invasive trees; invasive fish; invasive trees and fish. Invertebrate assemblages were sensitive to invasion from bass and/or wattle: in the presence of A. mearnsii the abundance of some cobble-dwelling taxa were reduced, while those of particle-feeding mayflies and chironomids increased, reflecting increased leaf litter and sediment produced by acacias. In the presence of bass the abundance of most invertebrate taxa, particularly Chironomidae and Baetidae, increased, whereas the algal-grazing Heptageniidae and Elmidae were moderately reduced. These changes in invertebrate assemblages, coupled with data on the biomass and diet of fishes, indicate that smallmouth bass, in contrast to indigenous fish, do not exert a strong influence on the abundance of their invertebrate prey. Bass remove indigenous insectivorous fish predators, thereby reducing predation on invertebrate prey, with consequent food-web effects that influence the invertebrate community assemblage.

The predatory impact of invasive alien smallmouth bass, Micropterus dolomieu (Teleostei: Centrarchidae), on indigenous fishes in a Cape Floristic Region mountain stream

Fish populations in the Rondegat River, a mountain stream in the Olifants-Doring system in the Cape Floristic Region, South Africa were surveyed to assess the impact of predatory alien invasive smallmouth bass Micropterus dolomieu (Lacepède) on the indigenous fishes. This was the first such attempt to quantify the predatory impacts of M. dolomieu within this region. The Rondegat River is home to five species of indigenous fish and is partially invaded by M. dolomieu, which has penetrated the lower river up to a waterfall barrier. Seasonal surveys were conducted at five sites above, and five below, the waterfall. Physical habitat was measured at each site. Four of the five indigenous fish species were absent at bass-invaded sites. Labeobarbus capensis (Smith), while still present below the waterfall, appeared to have suffered a near-total loss of post-spawning recruits. Analyses of physical habitat quality failed to explain the loss of indigenous fish below the waterfall, although sedimentation may have increased the vulnerability of the catfish Austroglanis gilli (Barnard) to M. dolomieu predation by obliterating benthic cover. Consequently, predation by M. dolomieu was presumed to be the critical mechanism explaining the loss of indigenous fishes in the lower Rondegat River.