Seasonal abundance,diet, and energy consumption of round gobies (Neogobius melanostomus) in Lake Erie tributary streams

Pennuto CM, Krakowiak PJ, Janik CE. Seasonal abundance, diet, and energy consumption of round gobies (Neogobius melanostomus) in Lake Erie tributary streams.
Ecology of Freshwater Fish 2010: 19: 206–215. © 2010 John Wiley & Sons A/S Abstract – The invasive round goby (Neogobius melanostomus) is a benthic invertivore that has become established in many lake and river systems of Europe and the United States, especially within the Great Lakes basin. Multiple reports document its negative impact on benthic macroinvertebrates and fishes in lakes and recent studies show fish and invertebrate communities in streams are equally at risk. We assessed the seasonal abundance of round gobies and their summer diet composition in tributary streams to Lake Erie. Populations of round gobies in the lower reaches of two tributary streams peaked in abundance in early fall, were absent in late winter, and reappeared in early spring, suggesting a possible out‐migration to the lake in winter. Population size distributions show a peak recruitment of young round gobies in July and low‐level recruitment through October. In this study, round gobies obtained most of their energy from amphipods, chironomids, and caddisflies compared to other invertebrates, and midges were consumed in greater proportion than their availability suggesting a preference for these prey. As the stream lacked molluscs, large round gobies remained generalist invertivores without a diet shift to molluscivory as has been reported in lake studies. The observations on recruitment and abundance, and possible out‐migration suggest the lower reaches of tributary streams may act as source populations for lake‐bound round gobies. It may be possible to take advantage of this out‐migration behaviour as a control strategy to capture large numbers of round gobies each winter.     

Downstream drift of round goby (Neogobius melanostomus) and tubenose goby (Proterorhinus semilunaris) in their non‐native area

Several Ponto‐Caspian gobiid species have recently expanded their ranges in Europe and North America. This is the first study to demonstrate passive downstream dispersal (drift) of the round goby (Neogobius melanostomus) and tubenose goby (Proterorhinus semilunaris) in newly colonised areas (River Dyje, Danube basin), a factor that could play an important role in their dispersal. Drift duration (i.e. number of dates on which the species was caught) in round goby was longer than that of both native species and tubenose goby, providing a possible advantage. Size of drifting fish was restricted to a narrow range of 6–8 mm and 5–8 mm for round and tubenose goby, respectively. Drift in both species occurred almost completely during hours of darkness (<1 lux) and fish size did not vary throughout the night. In both species, drift density increased significantly during the first hour after dusk. Round goby density gradually decreased up to dawn, while tubenose goby density varied throughout the night with no clear pattern. Drift of early life stages appears to be an important phenomenon that has not received adequate attention in studies of round and tubenose goby ecology and dispersal.     

Seasonal abundance and movement of the invasive round goby (Neogobius melanostomus) on rocky substrate in the Duluth–Superior Harbor of Lake Superior

Abstract – Despite its small size [adult: 60–130 mm, total length (TL)] and limited home range, the round goby (Neogobius melanostomus) has quickly become established throughout the Laurentian Great Lakes. Little information is available, however, on the natural dispersal pattern of this species. This capture–mark–recapture study utilised alphanumeric tags subcutaneously inserted into round gobies (n = 1228) along a 550‐m stretch of the Duluth–Superior Harbor shoreline to observe their movement over a 13‐month period. Recaptured round gobies (n = 415) exhibited highly leptokurtic movement distributions, and movement events were not correlated with fish size, gender or month. Our work indicates that round gobies >50 mm (TL) generally occupy an area less than the minimum sampling interval (25 m); however, occasional movement up to 50 m per day could facilitate range expansion in the Laurentian Great Lakes.     

Using acoustic telemetry and snorkel surveys to study diel activity and seasonal migration of round goby (Neogobius melanostomus) in an estuary of the Western Baltic Sea

In just two decades, round goby Neogobius melanostomus (Pallas) has dispersed throughout most of the Baltic and the North American Great Lakes. It thrives in shallow sheltered areas, where it is impacting native fauna. In Denmark, researchers, governmental institutions and fishers have joined in an effort to establish a sustainable round goby fishery. To do so, basic information about the movement of round goby is essential, so the movements of 50 round gobies were tracked using acoustic telemetry. The results revealed that activity took place mainly at night and seasonal migrations were common. The most frequent migration behaviour observed was a seaward return migration during winter, which was further confirmed by a snorkel survey. Tracking data also revealed riverine upstream dispersal. The results demonstrate that the round goby can be mapped using telemetry, and it is suggested that fishing for round goby may improve efficiency by targeting seasonal migration corridors.     

The influence of ontogeny and prey abundance on feeding ecology of age-0 Lake Whitefish (Coregonus clupeaformis) in southeastern Lake Michigan

A shift towards oligotrophic conditions in Lake Michigan has led to concern that altered trophic pathways are leading to lower early life survival and recruitment for Lake Whitefish (Coregonus clupeaformis). This study evaluated ontogenetic shifts in age-0 Lake Whitefish diets and evaluated how feeding ecology and the amount of food eaten varied with prey abundance and composition at a site in southeastern Lake Michigan during 2014–2017. Although prey densities varied among years, cyclopoid copepods were overall the most abundant prey available. In turn, cyclopoids were the predominant prey item in diets each year, particularly for the smallest larval Lake Whitefish. However, there was a tendency for the importance of cyclopoids to decline somewhat in each diet index as fish grew and other prey such as calanoid copepods, Bosminidae, Daphniidae and/or chironomids increased in importance. High zooplankton abundance, especially high cyclopoid abundance, available to the small size groups of Lake Whitefish (<21 mm) in 2014 was associated with high food mass/fish, high number of zooplankton eaten/fish, and low incidence of empty stomachs compared with 2015–2017. As fish grew, the impact of food abundance on prey consumption diminished somewhat, indicating that the relationship between fish feeding ecology and the prey environment can change quickly with fish size during the early life period.     

Factors influencing the abundance of three common nearshore fishes in south‐west Lake Michigan

Variation in the distribution and abundance of nearshore fishes is critical to understand food web processes and fishery management issues in Lake Michigan. This study characterised patterns in abundance of three common nearshore species, yellow perch Perca flavescens (Mitchell), round goby Neogobius melanostomus (Pallas) and alewife Alosa pseudoharengus (Wilson), in relation to spatio‐temporal, abiotic and biotic factors using gillnet sampling conducted across 5 years at multiple locations representing different substrates. Significant variations were observed in alewife and round goby catches between locations. A negative relationship between round goby and age‐0 yellow perch catch was observed, indicating potential competition between the two species. This study demonstrates that variability in nearshore fish communities can be driven by factors including substrate and interspecific interactions. Given the prominent role these species play in Lake Michigan's food web and thus their importance to fishery production, a thorough understanding of these factors is warranted.     

Intra‐population variability of life‐history traits and growth during range expansion of the invasive round goby,Neogobius melanostomus

Abstract Fish can undergo changes in their life‐history traits that correspond with local demographic conditions. Under range expansion, a population of non‐native fish might then be expected to exhibit a suite of life‐history traits that differ between the edge and the centre of the population’s geographic range. To test this hypothesis, life‐history traits of an expanding population of round goby, Neogobius melanostomus (Pallas), in early and newly established sites in the Trent River (Ontario, Canada) were compared in 2007 and 2008. Round goby in the area of first introduction exhibited a significant decrease in age at maturity, increased length at age 1 and they increased in GSI from 2007 to 2008. While individuals at the edges of the range exhibited traits that promote population growth under low intraspecific density, yearly variability in life‐history traits suggests that additional processes such as declining density and fluctuating food availability are influencing the reproductive strategy and growth of round goby during an invasion.     

Seasonal migration and fine‐scale movement of invasive round goby (Neogobius melanostomus) in a Great Lakes tributary

To determine whether invasive round goby (Neogobius melanostomus) from Lake Ontario were establishing a year‐round population in a tributary stream or migrating to the lake, we assessed population and individual movement patterns using mark–recapture assessment generated from weekly backpack electrofishing from May until November 2016. Round goby abundance was low in spring, peaked in summer and decreased again in autumn, suggesting seasonal inward stream migration and outward migration back to the lake. Adult round goby movement patterns were positively associated with changes in water temperature, but this was not the case for juveniles. Juveniles displayed a preference for shallow, upstream habitats. Observations of reproductive individuals coupled with a peak in juvenile abundance following the peak in adult abundance indicate that the tributary was used for reproduction and recruitment. The individual movement was primarily upstream in spring, and there was little net movement in summer, likely during reproduction. Downstream movement occurred in autumn over a short time period, suggesting rapid outmigration to the lake. The combined observations of seasonal population structure and individual movement suggest that tributary streams connected to large, infested waterbodies can be used for round goby reproduction and recruitment, rather than year‐round residence. This study provides evidence of round goby seasonal migration and their individual movement patterns within tributary streams, which complements an earlier study in Lake Erie tributaries and may be a common occurrence in other Great Lakes tributaries.     

Survival of smaller sport caught chinook, Oncorhynchus tshawytscha (Walbaum), and coho, Oncorhynchus kisutch (Walbaum), salmon from Lake Michigan and its management implications

Abstract The survival of small-sized (<50.8 cm) chinook salmon, Oncorhynchus tshawytscha (Walbaum), and coho salmon, Oncorhynchus kitsutch (Walbaum), caught by sport fishing was determined to assess the potential for increasing the size limit for these fish. Fishermen were recently catching smaller salmon than in the 1970s, but salmon growth rates had not changed. To be an effective management option, the survival rate of hooked and returned fish must be high. The overall survival rates were high: 76% for chinook salmon and 70% for coho salmon. There was no significant difference in survival of the coho salmon with size of hook used ( P = 0.31). Any mortality among fish was generally acute; fish hooked deep in the mouth or gills generally bled and died shortly after capture. Fish hooked in the gills had a significantly greater mortality ( P = 0.0002). The overall high survival rate for these species was the result of a small proportion of fish being hooked in the gills or deep in the mouth. Since the survival rate of the salmon was high, the size limit could be increased to allow smaller fish to grow to sizes preferred by sport fishermen.     

鄱阳湖刀鲚生殖群体特征及状况分析

研究鄱阳湖刀鲚群体的生殖特征和条件状况,为制定开发利用渔业资源的政策提供基础资料,以实现鄱阳湖刀鲚资源的可持续开发和保护。2013、2014年4-7月,分别在鄱阳湖及湖口八里江段进行了实地渔业资源调查,随机抽样定置网、流刺网和拖网采集的鄱阳湖刀鲚样本共658尾,测量了体长、体重、净重、性腺重和性别。雌性287尾、雄性371尾,体长18.6~38.1 cm、体重16.3~198.2 g。雌性刀鲚的体长和体重均大于雄性(P0.01),雌、雄个体的体长和体重差异均为极显著(P0.01)。随着体长的增加,雌雄体重差异越大;同等体长的雌性体重大于雄性。6月中旬、下旬的刀鲚卵巢发育仍参差不齐,有些可挤出卵粒,已发育到Ⅳ期末和Ⅴ期,有些还处在Ⅳ期初,但成熟系数在2.0以下的个体数量已显著减少。绝对繁殖力为960~13 820粒,相对繁殖力为123.4~753粒/g。平均丰满度为0.30±0.03(0.19~0.45)。鄱阳湖刀鲚雌雄比在1∶1.25~1.44,表现出雄多雌少的现象;刀鲚繁殖种群已呈现出逐渐变小的趋势,资源已出现严重的过度利用。     

Distribution of albacore (Thunnus alalunga) in the Indian Ocean and its relation to environmental factors

The distribution pattern of albacore, Thunnus alalunga, in the Indian Ocean was analyzed based on catch data from the Taiwanese tuna longline fishery during the period 1979–85. The Taiwanese tuna fishery began operating in the Indian Ocean in 1967. We used a geographic information system to compile a fishery and environmental database and statistically explored the catch per unit effort (CPUE) distribution of albacore. Our results indicated that immature albacore were mainly distributed in areas south of 30°S although some displayed a north–south seasonal migration. Mature albacore, which were mainly concentrated between 10°S and 25°S, also showed a north–south migration. Within 10°S and 30°S, the separation of mature, spawning, and immature albacore life history stages roughly coincided with the boundaries of the three oceanic current systems in the Indian Ocean. The optimal environmental variables for CPUE prediction by stepwise discriminant analysis differed among life history stages. For immature albacore, the sea surface variables sea surface temperature (SST), chlorophyll concentration and surface salinity were significant. For mature albacore, SST was significant, while for spawning albacore, the sub‐surface variables temperature at 100 m and oxygen at 200 m were significant. Spawning albacore evidently prefer deep oceanographic conditions. Our results on the oceanographic conditions preferred by different developmental stages of albacore in the Indian Ocean were compatible with previous studies found in the Pacific Ocean.     

Early life history and recruitment of black crappie (Pomoxis nigromaculatus) in two South Dakota waters

Abstract— We compared the early life history of black crappie ( Pomoxis nigromaculatus ) in Richmond (an impoundment) and Brant (a natural lake) lakes during 1994-1996. We expected variable recruitment (i. e., missing year classes) in the natural lake and more consistent recruitment in the impoundment. Larval black crappie abundance was always higher in Richmond Lake than Brant Lake. Peak abundance of larval black crappie was highest during 1994 in both waters. However, peak larval abundance did not correspond with fall trap-net catch per unit effort (CPUE) of age-0 black crappie, which was highest during 1995. Thus, recruitment of black crappie was not simply a function of the number of larvae hatched. Similar trends in catches of age-0 black crappie with the ichthyoplankton trawl and trap nets for both water bodies during 1994-1996 suggest that broad environmental factors similarly affected reproduction and recruitment in Richmond and Brant lakes.     

Diets of endangered silver chub (Macrhybopsis storeriana,Kirtland, 1844) in Lake Erie and implications for recovery

Silver chub (Macrhybopsis storeriana, Kirtland, 1844) is a native Cyprinid in Lake Erie, one of the Laurentian Great Lakes of North America. It is listed as endangered by the US state of New York and Canada, which has a recovery plan, and as special concern by the state of Michigan. Silver chub faces a potential threat to recovery from control efforts for invasive Grass carp (Ctenopharyngodon idella, Valenciennes 1844). Among the knowledge gaps for protection and restoration is current diet data. I describe the diet of silver chub from western Lake Erie in 2014, and I compare it to past studies to assess changes in diet through time. Silver chub captured in bottom trawls May–September 2014 were frozen in the field, and stomach contents were preserved in ethanol. Diet taxa were identified to the lowest practical taxonomic unit, then dried and weighed. Frequency of occurrence in silver chub diets was highest for Hexagenia spp. mayflies (79%). Dreissena spp. and Hexagenia spp. were both 41% of the diet by dry weight. Analysis of δ¹³C isotopes identified Hexagenia spp. as the primary source of carbon in silver chub. Compared to past studies, Dreissena spp. have mostly replaced Sphaeriidae and Gastropoda in silver chub diets. There also have been seasonal shifts in relative amounts of shelled organisms and Hexagenia spp. This study and past research suggest a functional link between silver chub and Hexagenia spp. abundance. Maintenance and recovery of silver chub may be dependent on maintaining Hexagenia spp. populations.     

Eradication of colonizing populations of zebra mussels (Dreissena polymorpha) by early detection and SCUBA removal: Lake George,NY

• 1. Since their introduction to North America, zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena rostriformis bugensis) have rapidly colonized North American fresh waters. Strategies for limiting the economic and ecological impacts of zebra mussels exist, but there are few examples where once zebra mussels have invaded a natural body of water they have been removed or managed without the use of ecologically destructive methods. The first successful attempt to eradicate a colonizing population of zebra mussels using SCUBA is reported here. Studies were conducted in Lake George, NY.
• 2. Since zebra mussel larvae had been detected prior to the discovery of adults in Lake George, a comprehensive management programme for zebra mussels was in place when mussels were found in 1999, at a single location in the southern part of the Lake (Lake George Village site). Efforts were quickly launched to remove as many mussels as possible by SCUBA with the intent of minimizing the risk of the population reproducing and establishing a permanent presence in the Lake.
• 3. Population size at the discovery site was initially estimated at fewer than 30000 animals. Between 1999 and 2007 more than 21000 animals were removed from the site, over 90% of them shortly after the colony was discovered. Continued monitoring of the site for larvae, recruitment, and growth suggests that the animals have not successfully reproduced since the project began. Since detection at the Lake George Village site, six separate colonizing populations at other locations in the lake were found and similar removal efforts appear to be having comparable success.
• 4. This study demonstrates that the combination of early detection, suboptimal habitat, proactive establishment of a rapid response and management plan, and cooperation of a comprehensive network of stakeholders can prevent a successful zebra mussel invasion.Copyright © 2009 John Wiley & Sons, Ltd.

     

日本鳗鲡幼体的耳石微化学分析及其环境指示元素筛选

在长江口日本鳗鲡鳗苗捕捞汛期,于长江靖江段采集日本鳗鲡幼体,采用同步辐射X射线荧光(XRF)定量分析方法测定了幼体矢耳石中14种元素的含量,分析了在海洋与淡水早期生活史阶段的微化学特征。结果显示,耳石中Ca和Sr为常量元素,Ba、Fe、Mn、Zn的含量也在1-10μg/g之间,Cr、Ni、Se、Co、Cu、Au则在1 mg/g以下。Ni、Cu、Mn、Cr、Co、Zn和Sr含量的稳定性较好,变异系数在30%以下;Se、Au的含量低且极不稳定,变异系数达40.8-75.0%;Fe在不同个体间存在显著的含量差异(p=0.007<0.05),但其他元素不存在个体差异。在海洋生活史阶段,Mn、Se、Co、Ba为强富集元素(BCFa-e >1000),Sr、Fe、Zn、Ni、Cu为中等富集元素(BCFa-e在100~1000)。除Sr、Ba和Se外,卵黄囊期和柳叶鳗期的耳石富集系数并无显著差异(p>0.05)。在淡水生活史阶段,Sr和Co为强富集元素(BCFa-e >1000),Se、Zn、Cu、Ba、Mn为中等富集元素(BCFa-e在100~1000),Ni、Fe为低富集元素(BCFa-e在10~100)。与海水阶段相比,耳石在淡水阶段的Fe、Ba、Mn、Se、Co、Ni富集系数均大幅减小,而对Sr、Zn、Cu的富集能力有所增大。分析表明,耳石内的Sr、Ba、Ni、Co为环境强响应元素,Fe和Mn为环境弱响应元素,Zn、Cu和Se为环境负响应元素,幼鳗自海洋至淡水的迁徙过程中,前者存在明显的时滞效应,但后两者的日间含量波动较大,缺乏响应的规律性。本文认为,用作鱼类迁移行为或栖息地环境变化的指示元素,需要具备耳石富集效应强、时滞效应小、不同环境间含量差异大、稳定性好、且为非必需元素等特点。从本研究结果看,只有Sr和Ba两种元素符合这些条件 。     

Prey selectivity and ontogenetic diet shift of the globally invasive western mosquitofish (Gambusia affinis) in agriculturally impacted streams

The dietary breadth of invaders can influence their success, and having a wide dietary niche can facilitate the spread and survival of invaders under a variety of resource scenarios. The western mosquitofish (Gambusia affinis) is a globally distributed freshwater invasive fish. The spread of G. affinis is associated with agricultural land use, although the trophic role it plays in degraded systems is not well understood. We analysed the invertebrate community in 11 stream reaches in the North Island of New Zealand, in catchments spanning a range (45%–90%) of agricultural land use to determine how prey availability changes with land use. We then analysed the gut contents of 400 G. affinis from the 11 sites to determine how diet varied with prey availability and ontogeny. Invertebrate communities varied along the agricultural land‐use gradient, both in regard to taxonomic richness and community composition. G. affinis consumed a wide variety of food items with invertebrates being the most dominant, in particular Culicidae, Copepods and amphipods were the most commonly consumed invertebrates. There was also an ontogenetic diet shift from microinvertebrates (Cladocera, Copepods and diatoms) to larger invertebrates, including Culicidae, amphipods and terrestrial invertebrates. G. affinis are capable of consuming a wide variety of prey in agricultural streams; their preferred prey are generally pollution‐tolerant taxa commonly found in degraded streams. Having a large level of dietary plasticity coupled with preferring prey that are often associated with degraded systems likely facilitates to the spread of one of the most widely distributed freshwater invasive fish.     

Seasonal spawning and wind‐regulated retention‐dispersal of early life stage Atlantic cod (Gadus morhua) in a Newfoundland fjord

Sequential ichthyoplankton surveys were used to determine the spatial and temporal distribution of eggs and larvae over coastal spawning grounds of Atlantic cod (Gadus morhua) in Smith Sound, Trinity Bay, Newfoundland, during the spring and summer of 2006 and 2007. Egg densities showed similar patterns for both years with two peaks in abundance in spring (March–April) and late summer (late July). A clear progression of development stages (1–4) was observed in spring and summer in 2006 and summer in 2007, suggesting retention of eggs within the Sound during these periods. Modelled predictions of vertical egg distributions indicated eggs were broadly distributed near the surface during spring (March–April), but were concentrated below the pycnocline (>10 m) within the inner portions of the Sound during the summer months (July–August). Back‐calculated peaks in spawning based on water temperatures were estimated at 11 and 4 April for 2006 and 2007, respectfully, with late season peaks centred on 21–24 July for both years. Environmental data indicated cooler water temperatures and periods of high wind stress in spring, and warmer, calmer periods late summer, consistent with higher retention and faster development times on the spawning grounds later in the season. We conclude that spring and summer spawning events result in different distributions of early life stages and may lead to different distributions of juvenile and adult fish.     

Efficacy of different types of live and non-conventional diets in endangered clown knife fish Chitala chitala (Hamilton-Buchanan) during its early life stages

In the present study, the growth and survival of early life stages (ELS) of Chitala chitala were studied in nylon hapa for 28 days, followed by rearing in fibreglass reinforcement plastic (FRP) tanks for a period of 30 days. Ten‐day‐old ELS of C. chitala reared in hapa were fed with three different diets namely Indian Major Carp (IMC) spawn (<8 mm), live tubifex and fresh fish eggs. In the second phase, 28‐day‐old ELS were stocked in 200‐lit FRP tank and supplied four different live diets namely live tubifex worm, chironomous larvae, zooplanktons and mosquito larvae. Fish accepted all types of diets in the experimental rearing period in both the systems. The experiments conducted in hapa showed a higher specific growth rate (SGR), weight gain per cent and survival rate in larvae fed with live tubifex (SGR=1.76±0.02) than fish eggs (0.77±0.31) and IMC spawn (0.46±0.12). The study carried out in FRP tanks revealed that SGR was higher in ELS fed on chironomous larvae (4.44±0.61), followed by mosquito larvae (3.29±0.40) and live tubifex (3.28±0.36), whereas minimum SGR was recorded with zooplanktons (2.84±0.66). A significant difference (P<0.05) in SGR, final mean weight and weight gain (%) was also recorded. The highest mean survival rate (100%) of ELS in an FRP tank was observed in chironomous larvae and zooplanktons, whereas with live tubifex and mosquito larvae the same survival rate (80%) was recorded. The rate of survival of the ELS reared in hapa varied from 65% to 85%. The experiments showed that ELS of C. chitala could be reared successfully in hapas and fibreglass reinforcement tanks for attaining better survivability and growth.