Dispersion of stocked brown trout, Salmo trutta L., and landlocked salmon, Salmo salar L., from stocking sites in Lake Oulujärvi, Finland

Movement and recaptures of two hatchery-reared brown trout, Salmo trutta L., stocks and landlocked salmon, Salmo salar L., released at different sites in regulated Lake Oulujärvi, were studied in relation to release site. Five groups of fish from each stock were released in approximately equal numbers. Most of the fish released in June and July were recaptured within 3 months, whereas the majority of the fish released in early winter (October and November) were caught the following spring, about 7–9 months after stocking. The release site had a significant effect on recapture rate. The results showed that fishing restrictions targeted mainly at gill net fishing are needed to preserve the stocked fish from overfishing. Significantly fewer recaptures were observed from the landlocked salmon stocking compared with brown trout. The recaptures from the landlocked salmon stocking indicated more active movement and less clumping compared with the two brown trout stocks.     

Movement, social cohesion and site fidelity in adult koi carp, Cyprinus carpio

Abstract  Koi carp is an ornamental variant of the common carp, Cyprinus carpio L., that was introduced to New Zealand in the 1960s and has since become a major aquatic pest. A total of 1265 wild adult koi carp were caught by boat electric fishing, dart tagged and released at multiple sites in the lower Waikato River and associated lakes and wetlands between September 2002 and February 2005. Subsequent recaptures by boat electric fishing and recreational fishing returned 76 koi carp (6% of all tagged fish). Of these, 85% were recaptured less than 5 km from their release site; only one fish moved more than 50 km. On seven occasions, pairs or small groups of koi carp (20% of all tag returns) that had previously been tagged and released at the same locations and times were subsequently recaptured together after considerable periods of time at liberty (mean 551 days ± 419 SD). Adult koi carp in the Waikato River showed a high degree of site fidelity, exhibited prolonged social groupings and females moved downstream more often than males.     

Movement of wild and experimentally stocked brown trout, Salmo trutta L., before and after a flood in a small Austrian stream

Weirs and traps were used to monitor the movement of two strains of stocked brown trout, Salmo trutta L. Within 24 h of stocking, 15% ( n  = 13) of a Danish strain and 21% ( n  = 19) of a hybrid strain moved at least 100 m from their release site. In the following 5–6 days, no further movement was found for Danish fish, but hybrid fish continued to move, totaling 32% ( n  = 29) of the fish stocked. During this same period, 36 wild brown trout (≈ 3.5% of the population) were captured, moving over the weirs. Two weeks later, and one week after a flood, 70% ( n  = 59) of the Danish strain were recovered within their release sites and 89% ( n  = 76) were recovered during an electric fishing survey within the 3.5-km-long experimental area. In contrast, 43% ( n  = 31) of the hybrid strain were recaptured in their release sites and 49% ( n  = 45) within the experimental area. The total recapture of wild adult fish was only 16% ( n  = 41). The flooding event was insignificant in comparison with strain-specific behaviours in determining patterns of movement and residency.Austria, brown trout, floods, movement, stocking.     

Assessment of residency and movement of the endangered bullhead (Cottus gobio) in two Flemish rivers

Abstract –  Residency and movement of bullheads ( Cottus gobio ) were assessed by mark-recapture from November 2001 to June 2002 in two Flemish rivers [Steenputbeek (SPB), Laarse Beek (LB)]. Although the majority of the recaptured bullheads (SPB: 66%; LB: 55%) was found in their initial tagging site before the spawning season, some fish had covered distances between 10–100 m (mean: 17 ± 2 m) and 10–70 m (mean: 18 ± 7 m), respectively. During the spawning season, the proportion of fish that moved (SPB: 58%; LB: 75%) and the distances travelled (SPB: between 10 and 90 m, mean 26 ± 3 m; LB: between 30 and 260 m, mean 133 ± 3 m) were significantly larger. In addition, analysis of individual movement behaviour of multiple recaptured bullheads showed that some fish were either always resident or mobile, while others switched between both behaviours. In general, our results suggest that not all bullheads exhibit sedentary behaviour but that the populations under study consist of both stationary and mobile individuals.     

Patterns of movement and habitat use by tigerfish (Hydrocynus vittatus) in the Upper Zambezi River (Namibia)

Abstract – During 6 November to 24 December 2000, 23 tigerfish [( Hydrocynus vittatus ), 30–54 cm] were tagged with radio transmitters in the Zambezi River (Namibia) to record habitat utilisation during low, rising and high water levels. The fish were tracked, on average, every fourth day during 23 November to 18 May. Two movement patterns were detected. Approximately 50% of the fish moved <1000 m among tracking surveys, staying within 'defined' home ranges. The remaining fish showed consistent site fidelity for periods, with long distance movements (>1000 m) to new areas among residency periods. Overall, mean distance moved between tracking surveys was 1447 m. Home range size varied among individuals, with a 95% probability of localisation within an average area of 276,978 m². The fish utilised a mean river stretch of 18,836 m (range = 90–71,840). All the fish were recorded in the main stem, and on average, 95% of the fixes were in the main stem during low water. However, the fish used temporary flooded areas to an increasing extent during the rising and high water period, but did not undertake long-distance migrations into the floodplains. Fish were sometimes near vegetation, but were never recorded into or under vegetation.     

Movements of creek chubs, Semotilus atromaculatus, among habitat patches in a plains stream

Abstract –  We studied summer movement patterns of creek chubs, Semotilus atromaculatus, in a low-gradient, sand-bottomed stream on the western plains of the United States. Creek chubs were highly associated with patches of cover consisting of wood or macrophytes. Movements among 37 patches in a 1.1-km segment were assessed in a mark-recapture study. Over 2-week intervals, 44% of recaptured fish changed patches. Net distances moved ranged from 4 to 606 m, median distance moved was 49 m. Of fish recaptured repeatedly during the four sampling periods, most (65%) changed patches at least once, but few were consistently mobile. Inter-patch distance was an important variable with a negative effect on creek chub movements. Inter-patch cover was less important, but had a positive effect on movements. Frequent, short-distance movements among habitat patches in summer are a component of the ecology of creek chubs and the spatial arrangement of patches, and intervening stream conditions appear to mediate those movements.     

Assessment of movements of resident stream brown trout, Salmo trutta L., among contiguous sections of stream

Abstract – The present authors studied the movements of resident stream brown trout, Salmo trutta L., in Valley Creek, Chester County, Pennsylvania, USA, using mark-recapture techniques as well as radio telemetry. The novel characteristic of this study is that the entire stream was sampled during recapture, thus minimizing the possibility of bias during this portion of the analysis. The authors tagged 627 trout between June and September, 1995, and made 94.6% of recaptures in December, 1995, and 98.5% of recaptures in March, 1996, within 800 m of the initial tagging sites. They also implanted six trout with radio transmitters and made 94.6% of contacts within 800 m of the initial implantation sites. The data, which were pooled from mark-recapture and radio telemetry studies, show that 95.5% of all recaptures and contacts were within 800 m of initial tagging sites. These results, derived from complete stream sampling, support previous studies indicating that a high percentage of resident stream salmonids remain in the same area of stream throughout the year.     

Is the winter period a severe bottleneck of anadromous riverine Arctic charr parr?

Abstract –  Winter growth and survival of wild individually tagged juvenile Arctic charr (1+ age) from a riverine anadromous stock, were studied in a small ice-covered (∼6 months) ground water brook (temperature ∼1 °C) connected to Skibotnelva in subarctic northern Norway. The overall winter survival was estimated to be 68% from late October 2005 to early May 2006. The recaptured charr were not significantly different in initial length or weight compared with the nonrecaptured fish suggesting low size-dependent mortality. The majority (98%) of the recaptured charr showed significant increase in size, with a mean increment of 62% from their initial bodyweight and 12% of the charr parr had more than doubled their weight. The mean specific growth rate was calculated to be slightly lower (0.27) than estimated values from a growth model (∼0.35). In addition, the condition factor increased significantly during the field experiment. These results are the first individual growth data on riverine anadromous Arctic charr parr under natural winter conditions, and indicate that charr can grow relatively fast during periods with low temperature and also that ground water brooks can be good over-wintering habitat for juvenile Arctic charr. These results suggest that the winter period is perhaps a less severe bottleneck than previously recognised for the cold-adapted Arctic charr.     

Movements of the yellowfin shiner, Notropis lutipinnis

Abstract— Yellowfin shiner, Notropis lutipinnis , movements were observed in two streams located near Clemson, South Carolina (USA). Subcutaneous paint tags were used to associate fish with the pools in which they were initially captured, tagged and released. Few mortalities related to marking techniques were observed in both captive and field-tagged fish. Tag longevity varied among paint colors used and anatomical locations marked. Movements were inferred from recaptured fish collected over a 12-month period. Recaptures within release pools were proportionally greater than movements outside release pools, although the sampling technique used likely overestimated recaptures within release pools. Recaptures outside release pools were more frequent in late spring and early summer, coinciding with the N. lutipinnis spawning season. The linear home range estimate for this species was 42.9 ± 79.0 m, although this represents a minimum estimate because complex movements by individual fish could not be detected.     

Homing patterns of Baltic salmon, Salmo salar L., from smolts released from two hatcheries in the River Dalälven, Sweden

The River Dalälven Baltic salmon, Salmo salar L., population has been maintained by stocking reared fish since the early 1920s. Initially, all rearing was carried out at one hatchery, but since the late 1980s two have been used. Both hatcheries are situated 9–10 km from the river mouth but some 600 m apart. All broodfish were caught in a single fish trap situated some 700 m upstream of the upper hatchery. The salmon smolts were released just below the water outlets of each hatchery, respectively. About 2% of the released smolts from each hatchery were tagged annually with Carlin tags. Total recapture rates were higher for smolts from the lower hatchery. A higher proportion of recaptured fish was reported from the home river for salmon from the upper hatchery. The migration within the river to the fish trap was more precise for fish from the upper station. Strays were very late in the season and of a higher number from the lower hatchery. Observations of jumping salmon by the outlet from the lower station indicated that salmon returned to that point. The lower recaptures in the trap were considered a result of a shorter river migration of salmon from the lower hatchery.     

Stocking of brown trout, Salmo trutta L.: effects of acclimatization

One-year-old hatchery brown trout, Salmo trutta L., ( n  = 16 520) from a sea-run, local brood stock were marked and released (scatter-planted) into the River Laisälven in northern Sweden. Eight different groups were created using Alcian blue and Visible Implant Elastomer tags. Half the fish were kept in small enclosures in four stocking areas for 6 days before release. The other half were released just after transportation. To evaluate the effect of acclimatization on post-stocking performance, the areas were electric fished 2 months later. During the electric fishing survey, a higher number of the acclimatized hatchery fish were recaptured than those released immediately. The growth rate of stocked fish differed significantly between stocking areas and fish held in enclosures grew more than those released directly. The rate of recapture of hatchery fish varied between stocking areas (6.4–17.4%). Movements of juveniles within and between the stocking areas were low, and only 3.6% of the recaptured fish were found in an area not originally stocked. These results showed that acclimatization of fish before release increases the number and size at recapture within a stocking area.     

Modelling the life-history variation of Arctic charr

Abstract –  A model based on proximate considerations of life histories of Atlantic salmon, Salmo salar , was examined for its applicability to fit the variation in life-history of wild Arctic charr, Salvelinus alpinus , based on a qualitative assessment of information related to growth and lipid dynamics of Arctic charr. The original salmon model is discussed in context of modifications required to account for added complexities in the life history of Arctic charr in relation to anadromy versus residency. A study from North Norway shows that individual charr that emigrate from the lakes to the sea, maintain a high growth rate in the lake in late summer and early autumn compared with resident fish. Their relatively low lipid level in autumn combined with a high rate of change of lipid during winter was associated with postponement of maturation in the anadromous individuals. Individuals that remain resident in the lake arrested growth in autumn. Their high lipid level in autumn combined with a low rate of change of lipid during winter was associated with maturation the following summer, without emigration from freshwater. Results from this and other related studies show similarities with the model derived from lipid and growth dynamics of Atlantic salmon. The adjusted charr model illustrates possible proximate explanations for the high variation in life-history strategies of Arctic charr. However, the model does not account for the characteristic return migration of immature charr into freshwater several weeks after their entry to the sea. The proximate physiological stimulus for this movement of immature fish is not entirely clear.     

Movement of common carp, Cyprinus carpio, in a regulated lowland Australian river: implications for management

Abstract  Introduced common carp, Cyprinus carpio L., is the most abundant large fish in the Murray-Darling Basin and past studies have considered it non-migratory. Movement information is, however, important for targeting control efforts to appropriate habitats and spatial scales. Movement patterns of common carp in the Murray River were investigated between November 1999 and August 2001. In total, 3337 common carp were boat electric fished and externally tagged. Of the 293 (8.8%) fish recaptured, up to 1898 days later, the majority (80%) moved <5 km. However, over 7% of the tagged population moved ≥100 km, and the maximum distance was 890 km. Intermediate-sized males moved the greatest distances, usually downstream. Conversely, females and larger males remained close to floodplain spawning areas. For improved management, there is a need to recognise different movement strategies within common carp populations.     

Recaptures and resource use of native and non-native brown trout, Salmo trutta L., released in a Norwegian lake

Abstract Rate of recapture (gill netting), habitat use, and diet of three strains of stocked brown trout, Salmo trutta L., were compared with resident brown trout in a Norwegian lake. The strains originated from an alpine lake, from a boreal lake, and from the native brown trout population in the lake. Overall recapture rate was 5–8% for all strains. The low recapture rate could be due to the relatively small size at stocking; mean fish length varied between 13.1 and 14.5 cm with strain and stocking method. Two years after release, the frequency of the different strains decreased from about 12% in the first year to stabilize at about 1%. The alpine strain showed the highest overall recapture rate, whereas the native strain was recaptured at an intermediate rate. The overall recapture rate of scatter-planted brown trout was higher than that of spot-planted brown trout. Immediately after being stocked, introduced fish ate less and had a less-varied diet than resident trout; however, stocked fish adopted a natural diet within the first summer. The distribution of trout between the pelagic and the upper epibenthic habitat was similar for both the resident and the stocked brown trout. Results indicate that the habitat use of stocked brown trout is adaptive and becomes similar to that of indigenous fish.     

Microhabitat use, movements and abundance of gilt darters (Percina evides) in southern Appalachian (USA) streams

Abstract –  We examined microhabitat use by gilt darters ( Percina evides ) in two streams in the south-eastern USA. Darters were over-represented in erosional microhabitats with higher average velocities and more cobble. Male darters tended to show stronger selection than females. Size-based analyses showed that larger (≥60 mm) gilt darters tended to use microhabitats with more heterogeneous substrata and more boulder than smaller (≤59 mm) darters. We also conducted a short-term movement study and calculated population estimates based on mark–recapture data in autumn 2005. Darters moved both long and short distances with 40% of all recaptures occurring within 5 m of the initial capture point. Using Program mark and model-averaged parameter estimates gilt darter density was 0.31 darters·m⁻² (225 darters/730 m²). Conservation of this species will require the preservation of erosional habitats in streams.     

Residency of adult Atlantic cod (Gadus morhua) in the western Gulf of Maine

A mark and recapture study of cod in the western Gulf of Maine was conducted to study the seasonal movements of fish, particularly as they related to areas closed to commercial fishing. A total of 27,772 cod were tagged, and 1334 (4.8%) were recaptured with sufficiently detailed recapture location and date to be included in the study. Results indicated that the group is resident to the area and sedentary. Although there were a small percentage of fish (2.5%) that traveled long distances (>100 km), most were recaptured near their release location. There was no linear relationship between fish length and linear distances traveled, and linear distance traveled was only weakly related to days-at-large. For all groups of cod tagged and released in particular areas and months, mean distances traveled were small (<65 km), rates of travel were slow (<0.2 km/day), and rates of group dispersion were <50 km²/day. There were no recognizable spatial or temporal patterns in the mean angles of travel for groups released in various month/area combinations, and the angular deviations associated with the mean angles were quite large. Although there seems to be little pattern in the movement of cod in our study area, temporal and spatial changes in abundance indicate that movements are occurring.

The general pattern was a concentration of large cod into one small, inshore area (Area 133) in both the spring and winter, and dispersion from this area in the ensuing months. Monthly percentages of ripe cod in Area 133 provide evidence for two spawning groups; a winter group that spawns from November through January, and a spring group that spawns from April through July. Thus it is likely that the observed spring and winter concentrations of fish in Area 133 were associated with spawning. Fish in the spring group were the largest encountered in the study. The study also provided some evidence of natal homing, i.e. a return to the same spawning grounds year after year, for the spring spawning group. Although there is some exchange of fish between most of the closed areas, the timing of the closures appears to protect the largest aggregations of cod.     

Investigating the catch returns and growth rate of wels catfish, Silurus glanis, using mark–recapture

Abstract In January 2004, 46 wels catfish, Silurus glanis L., between 51 and 135 cm total length were tagged and released into a 0.4 ha recreational, catch and release, lake fishery in the UK, and their recapture by anglers monitored throughout the year. Of the 46 tagged fish, 16 were recaptured by anglers during 170 capture events. Some individual fish were captured up to 26 times. Catfish <75 cm appeared to be the least susceptible to capture and fish >100 cm most susceptible. Frequency of captures increased with temperatures >10 °C and peaked between June and August. Selected recapture weight data were used to produce a mass specific growth equation and revealed specific growth rate was a decreasing function of body mass over the size range of the recaptured fish. Their growth was slower than fish from elsewhere in their distribution range.     

Variability in movement dynamics of topminnow (Fundulus notatus and F. olivaceus) populations

Abstract – Movement and dispersal patterns are key biological processes across a range of organisational levels. The Fundulus notatus species complex includes several species with similar ecological niches that exhibit broadly overlapping ranges. We conducted a mark–recapture study on two of the most widely distributed members of this species complex to improve our understanding of their movement and habitat use. A population of F. notatus was studied between June and August of 2008 and 2009 in Cahokia Creek, a small tributary of the Mississippi River in Illinois, along with a parallel study of Fundulus olivaceus between May and July of 2009 in Big Creek, a tributary of the Pascagoula River in Mississippi. Fish were recaptured approximately weekly, and habitat variables were measured. Estimated daily movement rates varied significantly both between locations and between years. Fundulus olivaceus in Big Creek moved <1 m per day, while F. notatus in Cahokia Creek in 2009 moved nearly 23 m per day. The distribution of movements was strongly leptokurtic in all three data sets. Differences in movement rates were attributed to significant differences in population size and habitat characteristics. Our data did not support the hypothesis that populations consist of distinct mobile and resident components. Instead, individual fish went through periods of little or no movement followed by extensive movement (consistent with the home range shift model of fish movement). We discuss the implications these results have for contact zone dynamics between these two species.     

A collaborative approach to investigate site fidelity, home range, and homing behavior of cabezon (Scorpaenichthys marmoratus)

Understanding the area use requirements of species targeted for protection by marine protected areas (MPAs) is critical to the future conservation efforts of economically important fish species. Knowledge of home range size and site fidelity is essential in determining whether species will benefit from the protection offered by a MPA, the size of the area needed to protect individuals, and the extent to which surrounding unprotected areas may be supplemented through post-recruitment movement or “spillover”. We utilized a traditional mark and recapture approach, along with GIS spatial analysis to investigate the site fidelity, home range, and homing behavior of the economically important fish species cabezon (Scorpaenichthys marmoratus) on the south central coast of California. In collaboration with members of the commercial live-fish fishery, a total of 1240 sub-adult and adult cabezon were tagged during 10 days of fishing from September to December of 2004 along ∼18 km of coastline. A public awareness and reward program resulted in 330 total recaptures from 290 different individuals (23% recapture rate) with recaptured individuals at liberty up to 1000 days after initial tagging. A majority of individuals displayed high site fidelity, with 81% of recapture events occurring within 100 m of their initial capture locations, and only 9 individuals (.03%) recaptured greater than 1 km. Most individuals (64%) displayed home ranges less than 1000 m². Ten individuals recaptured after experiencing translocation of up to 5.3 km displayed strong homing behavior, returning to within 14 m of their initial capture locations. Findings suggest that under circumstances where suitable habitat is available in nearby unprotected areas, that adult “spillover” will likely be limited to areas within 100 m from MPA boundaries. In addition, the size of the area needed to protect individual cabezon, should be at least 1000 m². Findings from this study demonstrate many of the potential benefits of scientists and fishers working together to investigate area use patterns of economically important fish species to facilitate future design and assessment of MPAs.     

Movement of the fluvial form of masu salmon, <Emphasis Type="Italic">Oncorhynchus masou masou</Emphasis>, in a mountain stream in Kyushu,Japan

Using mark-recapture methods, the movements of the fluvial form of masu salmon (Oncorhynchus masou masou) in a mountain stream on the island of Kyushu, Japan, were studied. Most (78%) of the masu salmon were recaptured in the pool in which they had been originally caught and tagged. Of those that moved between pools, the proportion of individuals that moved during the breeding period was not significantly higher than the proportion that moved during the non-breeding period. However, during the breeding period, a higher proportion of larger salmon moved than did smaller fish. The proportion of mobile large males during breeding period was higher than that for small males. Also, it was found that a few individuals showed long-range movement in the autumn. As a long-term movement, 78 individual fish (65%) that were recaptured more than three times showed high sedentary tendencies. Sixteen individual mobile fish (13%) moved and returned to the original pool. Fluvial form of masu salmon in Kyushu show a high sedentary nature; however, large mature males seem to actively move in search of female during breeding period.