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51.
KO FUJIOKA ALISTAIR J. HOBDAY RYO KAWABE KAZUSHI MIYASHITA KENTARO HONDA TOMOYUKI ITOH YOSHIMI TAKAO 《Fisheries Oceanography》2010,19(3):183-195
The spatial habitat utilization of juvenile southern bluefin tuna in southern Western Australia was investigated using automated acoustic receivers with acoustic transmitters implanted in tagged fish during three austral summers (2004/2005, N = 79 fish, 2005/2006, N = 81, 2006/2007, N = 84). Seventy acoustic receivers were deployed at three cross-shelf lines and three coastal topographic features (lumps) between December and May. We observed markedly different patterns of habitat utilization between the three seasons: (i) aggregation at lumps in 2004/2005 and 2006/2007, and (ii) wide distribution over the continental shelf (i.e., few occurring at lumps) in 2005/2006. Vertical profile by conductivity-temperature-depth casts showed these spatial shifts were caused by interannual changes in the presence of sub-Antarctic water. The sub-Antarctic water was present in the subsurface layer close to the continental slope only during 2005/2006, and the area had higher chlorophyll-a concentrations than the coastal areas, including at the lumps. These environmental characters, related to the nutrient rich sub-Antarctic water, appear to have a strong influence on fish distributions in 2005/2006, and may occur generally during La Niña events. Interannual fluctuations in habitat utilization will influence detection of fish in recruitment monitoring surveys and thus bias the resulting juvenile abundance indices. 相似文献
52.
Abstract – Fishery biologists have documented small home ranges, relative to available habitat, for many littoral freshwater fishes. Home ranges for pelagic species, such as white bass Morone chrysops , are generally not well described, yet are thought to be large. We studied white bass movement using acoustic telemetry in two irrigation reservoirs of the Republican River basin in south-western Nebraska. Acoustic transmitters were implanted in fall of the previous year and tracking occurred a minimum of once per week throughout spring (mid-March to May) 2007 and 2008. Linear home ranges were calculated from observed locations of individual fish. Twelve of the twenty-seven tagged fish with at least five locations exhibited localised home ranges throughout the spring whereas the remaining fish exhibited home ranges extending across large portions of each reservoir. Home range size was not correlated with fish size or condition. 相似文献
53.
Rodents are efficient invaders on a global scale and pose a significant threat to native biotas, particularly in systems such as oceanic islands which support a reduced suite of mammals. Pacific rats (Rattus exulans) are implicated in extinctions, range restrictions and declines of vulnerable endemic faunas throughout the Pacific. However, research into the behavioural and ecological modifications that enable native species to persist in the presence of Pacific rats is scant. We examined the population structure, behaviour and microhabitat use of Duvaucel’s geckos (Hoplodactylus duvaucelii; radio-telemetry), and Pacific rats (spool-and-line tracking) on three New Zealand offshore islands with different histories of rat incursions and eradication: (1) Green Island, historically rat-free, (2) Korapuki, from which rats were eradicated 20 years ago, and (3) ōh?¯nau, before and 6 months after rat eradication. Although Pacific rats and Duvaucel’s geckos shared habitat at a broad spatial scale, little overlap in micro-habitat use existed where they were sympatric. In the presence of rats, Duvaucel’s gecko capture rates and recruitment were reduced. However, 6 months after rat eradication, and prior to any recruitment, capture rates of adult geckos increased fourfold and geckos were using a greater proportion of habitat preferred by rats. Thus, we provide strong empirical evidence that Pacific rats ecologically displace Duvaucel’s geckos. Highly plastic spatial avoidance behaviour by native prey species in response to the presence of introduced rodents may enable geckos to persist in sympatry with rodents at least in the short-term. 相似文献
54.
Fine‐scale movement ecology of a freshwater top predator,Eurasian perch (Perca fluviatilis), in response to the abiotic environment over the course of a year
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Shinnosuke Nakayama Stefan Linzmaier John Briege Thomas Klefoth Tonio Pieterek Robert Arlinghaus 《Ecology of Freshwater Fish》2018,27(3):798-812
Fine‐scale underwater telemetry affords an unprecedented opportunity to understand how aquatic animals respond to environmental changes. We investigated the movement patterns of an aquatic top predator, Eurasian perch (Perca fluviatilis), using a three‐dimensional acoustic telemetry system installed in Kleiner Döllnsee (25 ha), a small, shallow, mesotrophic natural lake. Adult piscivorous perch (N = 16) were tagged and tracked in the whole lake at a minimum of 9‐s intervals over the course of one year. Perch increased swimming activity with higher water temperature and light intensity. Air pressure, wind speed and lunar phase also explained perch movements, but the effects were substantially smaller compared to temperature and light. Perch showed a strong diel pattern in activity, with farther swimming distances and larger activity spaces during the daytime, compared to the night‐time. To investigate the influence of prey distribution, we sampled the prey fish in both littoral and pelagic zones in both day and night monthly using gill nets. We found that the prey fish underwent diel horizontal migration, using the littoral zone during the day and the pelagic zone during the night. However, perch showed the opposite patterns, suggesting either that the prey fish avoided predation risk or that the horizontal diel migration of perch was driven by other mechanisms. Our results collectively suggest that the movement ecology of piscivorous perch is mainly governed by a foraging motivation as a function of abiotic variables, especially temperature and light. 相似文献
55.
Site fidelity,diel and seasonal activities of yellow‐phase Japanese eels (Anguilla japonica) in a freshwater habitat as inferred from acoustic telemetry
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Hikaru Itakura Yoichi Miyake Takashi Kitagawa Shingo Kimura 《Ecology of Freshwater Fish》2018,27(3):737-751
Japanese eels (Anguilla japonica) perform large‐scale oceanic migrations between their spawning ground and growth habitats in continental waters during life history. However, between these migrations, they spend most of time in growth habitats such as rivers. To investigate the diel and seasonal activities, homing behaviour and home range of yellow‐phase Japanese eels in the lower reach of the Tone River, we tracked them throughout a year using a fine‐scale positioning system (VPS) based on acoustic telemetry. The tracked eels were generally nocturnal, but not exclusively. They were mainly mobile from spring to autumn, with little or no activity observed during winter. A transport‐release experiment showed that most eels returned to their original capture area within 13 days after release. The eels had very small home ranges (mean ± SD = 0.085 ± 0.068 km2), core areas (0.014 ± 0.014 km2) and linear home ranges (744 ± 268 m). They also tended to be distributed on one particular side of the river (right or left bank) and in one particular shore type (revetment or vegetation), rarely moving from one to the other. This study provides evidence for nocturnal, dormancy, homing behaviours, limited habitat use and small home range size in Japanese eels. The eels clearly showed strong fidelity to a “familiar” site, which contrasts with the long distances travelled during upstream and downstream migration phases in the river, and during spawning migrations in the ocean. 相似文献
56.
Jason D. Thiem Ben T. Broadhurst Mark Lintermans Brendan C. Ebner Rhian C. Clear Daniel Wright 《Ecology of Freshwater Fish》2013,22(1):145-156
Knowledge of the movement patterns of threatened fishes aids their conservation management and informs sustainable development of natural resources including freshwater. Prior to the expansion of a temperate upland reservoir in Australia, we used radio telemetry to compare seasonal differences in the diel movements of adult endangered Macquarie perch (Macquaria australasica) (235–414 mm total length) in Cotter Reservoir, Australian Capital Territory. Macquarie perch exhibited a diel range of 389 ± 46 m, a diel mobility of 769 ± 93 m and diel area use of 24008 ± 5595 m2 among four seasons. Diel range was significantly higher in winter compared with other seasons, and diel mobility was negatively correlated with fish size among four seasons. Macquarie perch inhabited deeper water in summer across the diel cycle (7.2 ± 0.5 m) in comparison with other seasons (spring: 3.8 ± 0.3 m, autumn: 3.0 ± 0.2 m, winter: 3.0 ± 0.3 m). Within seasons, both remote and manual telemetry identified that diel activity was predominantly crepuscular. Prey availability and the threat of avian predation represent the most likely explanations for the differences in seasonal movements. In a reservoir where expansion will likely result in a loss of critical habitat (emergent macrophytes) for this endangered species, we use site‐specific knowledge of the spatial ecology of Macquarie perch to inform the placement of shelter habitat prior to filling the enlarged reservoir. 相似文献
57.
Danielle M. Frechette Elsa Goerig Normand E. Bergeron 《Fisheries Management and Ecology》2020,27(1):20-31
Transport of salmonids allows upstream migrating adults to bypass barriers to migration, for example hydroelectric dams or adverse habitats. Downstream movement (“fallback”) after transport is common and removes individuals from spawning populations, with possible detrimental consequences for population productivity. Time‐to‐event analysis was used to determine effects of fish characteristics, transport conditions and environmental variables on fallback by adult Atlantic salmon transported to an inaccessible river reach as a population enhancement strategy on the Rivière Sainte‐Marguerite Nord‐Est (Québec, Canada). Of 68 salmon transported, 19 exhibited post‐transport fallback within seven days of transport. Fork length (FL) was the only factor that increased risk of post‐transport fallback; there was a 5% increase in the proportion of large salmon (≥780 mm FL) exhibiting post‐transport fallback relative to individuals of median size (750 mm FL). Although the present study was limited by small sample size, the findings will help inform design of transport programmes in freshwater systems. 相似文献
58.
Hugo Flvio Richard Kennedy Dennis Ensing Niels Jepsen Kim Aarestrup 《Fisheries Management and Ecology》2020,27(1):92-101
The River Bush (Northern Ireland) is an index river for the estimation of Atlantic salmon, Salmo salar L., stock size, population dynamics and marine survival rates. Marine survival estimates are based on the number of smolts counted at a trap 3.5 km upstream of the river outlet. The survival from release to coastal inshore waters for acoustic‐tagged smolts released at the Bushmills trap varied between 32% and 68%, with both year and brightness during river exit playing a significant role in explaining the variations in survival. This constitutes an important survival bottleneck. Contrary to true marine mortality, this significant loss of smolts in the river and nearshore environments could be reduced by focused management actions. More studies on other rivers, where smolts are enumerated above the head of tide, could further partition smolt and post‐smolt mortality, help differentiate true marine survival and help understand fluctuations in adult returns. 相似文献
59.
Einar Krgenberg Eva B. Thorstad Rein Jrvekülg Odd Terje Sandlund Ene Saadre Finn
kland Mart Thalfeldt Meelis Tambets 《Fisheries Management and Ecology》2020,27(1):32-40
Salmon smolts were released upstream of a run‐of‐river hydropower site and recaptured downstream for inspection. Descending fish behaviour through three possible migration routes (turbines, fishway, spillway) was analysed using telemetry, fyke nets and diving. Tagged smolts did not follow the main water flow; over 70% used the fishway, which received only about 10% of the flow. The turbines received about 80% of the water, but <25% of the smolts. Smolts were not fully stopped from entering the turbines by the 25‐mm bar racks. Mortality of smolts passing through the Kaplan turbines was at minimum 36%. No mortality was found in fish moving through the fishway or spillway. This shows that small and fast‐rotating Kaplan turbines can cause relatively high mortality. No mortality in alternative migration routes resulted in a total mortality for descending smolts at the hydropower station of 8.5%, emphasising the importance of providing functional alternative migration routes. 相似文献
60.
Jonathan D. Bolland Leona A. Murphy Robert J. Stanford Natalie V. Angelopoulos Nicola J. Baker Rosalind M. Wright Jake D. Reeds Ian G. Cowx 《Fisheries Management and Ecology》2019,26(1):76-85
Downstream passage of European eel Anguilla anguilla (L.) in catchments with pump(s) for water level management is a major concern. Catchment‐wide acoustic telemetry revealed silver eels quickly migrated downstream through unobstructed reaches (n = 12; mean ± SD = 17.9 ± 1.9 km/day). Fourteen of 17 acoustic‐tagged eels detected at the pumping station (82.1%) retreated back upstream and ten (58.8%) passed through pumps after delays (9.5 ± 11.0 days). Multi‐beam sonar imaging across the intake screen (55‐mm gaps) revealed that peaks in migration occurred during the nights preceding the new moon but 76.7% retreated back upstream. All passive integrated transponder (PIT)‐tagged eels recaptured (n = 56) downstream of a large (2.23‐m diameter) mixed flow pump survived but 96.5% had minor injuries, reduced physical condition and/or abnormal behaviour. By contrast, 64.7% of PIT‐tagged eels recaptured (n = 17) downstream of a small (0.8‐m diameter) axial flow pump died. No acoustic‐tagged eels that passed through the small axial flow pump (n = 10) performed onward migration at sea, unlike “control” eels released downstream (n = 11). This evidence may help develop effective remediation measures, such as operational changes, to maximise escapement of catadromous eel species at pumping stations. 相似文献