Suitable Spawning Habitat Research Articles

Seasonal Movements and Behaviour of Adult Barbel Barbus barbus, a Riverine Cyprinid Fish: Implications for River Management

To provide information on the movements and localized activity of barbel Barbus barbus (Cyprinidae) in a river containing potentially obstructing weirs, 31 adult barbel were radio-tracked in the River Nidd, a tributary of the Yorkshire Ouse, North East England between June 1993 and September 1994. Barbel exhibited substantial movements, ranging from 2 to nearly 20 km. Four fish are known to have moved between the Nidd and the Ouse, demonstrating that at least a part of the barbel population utilize the Nidd and Ouse at different times of the year. Range of upstream movement was restricted by the presence and nature of several weirs, including Skip Bridge flow-gauging weir. Low levels of spawning downstream of Skip Bridge weir appear to have been due to a lack of suitable spawning habitat. Movements followed a seasonal pattern, with males and females migrating upstream in spring to spawn on gravel beds. Females moved downstream more quickly than males over the summer months. Both sexes moved downstream in autumn and winter. Day length and water temperature were the best predictors in relation to distance moved up the River Nidd. Descriptive models, relating movement to water temperature and day length, are provided. For both sexes, localized activity varied greatly on both diel and seasonal scales, and was mainly associated with foraging. During summer there was typically a bimodal pattern of diel activity with peaks usually in early morning and late evening. In winter, mean daily activity was less than 20% of peak summer levels and fish were relatively dormant. In winter, diel activity patterns exhibited a single peak towards dusk. Mean daily activity levels for each month were linearly correlated with mean monthly water temperatures, even during the months where movement to and on the spawning sites occurred. The importance of natural migrations and seasonal activity patterns for barbel, and likewise many other riverine cyprinids, has probably been underestimated for a wide variety of river systems. As major components of riverine fish communities, the importance of seasonal movements of mobile cyprinid species should be considered when constructing weirs and other obstructions. Greater consideration should be given to ways of mitigating effects of existing barriers to movement of non-salmonid species.

Lessons to be Learned from Attempts to Restore Salvelinus Species Other Than S. namaycush: a Review of Reproductive Behavior

Published literature was reviewed on spawning and early rearing habitat of Salvelinus species, other than S. namaycush, for information on the success of attempts to introduce these species into new habitats, and to restore these species into habitats from which they had been eliminated. Competition from other fish species, particularly coregonids and salmonids, appears to lessen the chances of successful introductions of these species, whether to new or previously occupied habitats. Predation by esocids, osmerids, and other salmonids is also a factor reported to reduce the likelihood of success of introductions and restoration attempts. Loss of spawning habitat and nursery habitat through siltation, eutrophication, or lowered water levels are additional variables preventing successful introductions or reintroductions. Restoration of historical spawning areas, or provision of new, suitable spawning habitat can lead to successful recruitment by introduced or reintroduced Salvelinus species. Stocking appropriate life stages was important for successful introductions or reintroductions. In general, older/larger fish were more likely to survive and reproduce after stocking.

Effects of Improved Water Quality and Stream Treatment Rotation on Sea Lamprey Abundance: Implications for Lake Trout Rehabilitation in the Great Lakes

Efforts over the past 25 years to improve water quality in the Great Lakes basin may be counteracting progress toward lake trout rehabilitation that has been made possible by sea lamprey control. Improved water quality in streams has been linked to increased amounts of suitable sea lamprey spawning and ammocoete habitat leading to increased sea lamprey production. To assess the impact of improved water quality on sea lamprey production, we simulated transformer (young adult stage) production in a model stream assuming 50%, 75%, and 100% habitat availability. We also assessed the effect of lengthening the lampricide treatment cycle in streams; a proposed solution to inadequate funding of the sea lamprey control program. Increasing habitat availability dramatically increased the number of transformers produced in the stream; for example, doubling the available sea lamprey habitat resulted in a 2.5 fold increase in sea lamprey production. In addition, we found that the combined effects of improved water quality and lengthened lampricide treatment rotation caused transformer production to increase at a faster rate than either factor acting alone. Increased sea lamprey production directly impacts lake trout mortality and retards efforts toward achievement of lake trout rehabilitation goals. To counteract the improvement of sea lamprey habitat in tributaries, sea lamprey control efforts must be increased in order to enable lake trout rehabilitation to succeed.

Assessment of Lake Trout Spawning Habitat and Egg Deposition and Survival in Lake Ontario

Identification of the amount of lake trout spawning habitat and its actual use by lake trout in Lake Ontario is important for re-establishment of this species. From a combination of hydrographic field data, bathymetry measurements, and video observations, 20 reputed spawning sites, 14 of which were considered to be historically important, were evaluated for possible use by lake trout. Based on preliminary evaluations 13 of the 20 sites were rejected for further study because of inappropriate substrate or excessive infilling of interstitial spaces. Additional, more intense evaluations were made of seven sites, five that were of historical importance and two that were man-made. These seven sites had areas of suitable spawning habitat of from 6 to 4,000 m2, minimal water depths of from 2.2 to 10.8 m, mean cobble diameters of 9.8–20.0 cm, and slopes of 20–45°. Lake trout egg densities, estimated from recoveries in egg nets deployed in 1992, ranged from a mean of 6 to 6,200 eggs m−2 and the highest densities were found at man-made sites. The actual egg deposition on the seven sites studied intensely amounted to only 0.0003 to 0.6% of the potential deposition if all the lake trout that survived from stocking within a 30 km radius of each site spawned there.Egg survival to the eyed stage ranged from 21 to 82% and was inversely related to wind fetch. Spawning was earlier in western than in eastern Lake Ontario and was related to the rates of fall cooling. Duration of the spawning period ranged from 1 to 39 days but the low estimates were from collections of only a few eggs. A swim-up mortality syndrome observed in eggs reared in a laboratory was high, ranging from 31.0 to 74.5%. The potential for lake trout restoration in Lake Ontario appears to be limited by a scarcity of good spawning sites, low egg deposition on spawning sites recognized by researchers, and excessive swim-up mortality.

Assessing Habitat Requirements of Young Colorado River Cutthroat Trout by Use of Macrohabitat and Microhabitat Analyses

Abstract We used both microhabitat and macrohabitat analyses to better assess habitat requirements of young Colorado River cutthroat trout Oncorhynchus clarki pleuriticus. Microhabitat analyses revealed that among a range of stream types, young cutthroat trout consistently preferred slow water (<0.06 m/s) and depths over 3 cm. Suitable habitat of this type was provided by different types of pool habitat within the geomorphically diverse study streams. Macrohabitat analysis indicated that the density of young cutthroat trout was positively correlated with the abundance of spawning gravel and negatively correlated with stream depth (adjusted R 2 = 0.67). This relationship helped explain the absence of young cutthroat trout from some stream reaches that had suitable microhabitat but that often lacked suitable spawning habitat. The two types of habitat analysis provided complementary information concerning the habitat requirements of young Colorado River cutthroat trout in the study streams.

Beach erosion and geochemical factors: Influence on spawning success of horseshoe crabs (Limulus polyphemus) in Delaware Bay

Horseshoe crab spawning activity is spatially patchy within the Delaware Estuary. This study investigated the importance of geochemical and erosional factors to the selection of breeding beaches. Two sandy beaches in Cape May county, New Jersey, USA, were studied; one beach had been subjected to considerable erosion, exposing underlying peat; the second beach, less than 1 km away, had only traces of peat. Reduced sediments with high levels of hydrogen sulfide were correlated with the presence of peat, and significantly fewer crabs utilized sediments in the proximity of peat beds for reproduction. The lower spawning activity on the beach in the vicinity of exposed peat, suggests that crabs may detect, at a distance, the nature of sediments and the quality of beach for spawning activity. Active salt marsh and peat-bank sediments dominate the upper bay shore; these sediments are unsuitable, or at best marginal, for horseshoe crab reproduction. Extensive bulkheading of eroding sandy beach along several New Jersey shore communities has further restricted the availability of suitable spawning habitat, making the remaining stretches of optimal sandy beach critical to the reproductive success of this species.

Population Dynamics of Yellow Perch (Perca flavescens), Sauger (Stizostedion canadense), and Walleye (S. vitreum vitreum) in Four Main Stem Missouri River Reservoirs

Percid populations have generally increased in abundance relative to other groups of fishes in the 15–25 yr four large reservoirs have been operational on the Missouri River in South Dakota. Saugers (Stizostedion canadense) were initially the most abundant percid, but their numbers gradually declined, probably because of the reduction in river spawning habitat and the increase in water clarity. Yellow perch (Perca flavescens) increased to high population levels as the reservoirs filled but later decreased in abundance. Walleye (S. vitreum vitreum) populations were the slowest to develop in the reservoirs, probably because of initial lack of suitable spawning habitat; they later became well established.The yellow perch was one of the most important forage species in the reservoirs, and walleyes and saugers the primary predator and sport fishes. Sportfishing quality 15–25 yr after impoundment was good, but harvest remained low because of the large size of the reservoirs, inadequacy of facilities for anglers, and the relatively sparse human population. Reproductive success was the primary factor regulating the abundance of percids. Year-class strength was primarily determined by climatic rather than biological factors. Above-average precipitation presumably enhanced reproductive success, both directly by increasing the quantity and quality of spawning substrate through higher stream flows and water levels, and indirectly by providing a larger forage supply, thereby apparently reducing predation on young percids, as well as cannibalism. Kew words: Percidae, reservoirs, Missouri River, Stizostedion, Perca, population dynamics, ecology, precipitation, water level