Swimming Depth Research Articles

Habitat and behaviour of adult yellowfin tuna (Thunnus albacares) in the waters off southwestern Taiwan determined by pop-up satellite archival tags

Yellowfin tuna (Thunnus albacares ) is an economically important species for longline and trolling fisheries in the waters off the southwestern coast of Taiwan, yet this species' movement patterns remain poorly understood. This study provides the first information on the movement and behaviour of adult yellowfin tuna using pop-up satellite archival tags in the waters off the southwestern coast of Taiwan. In total, 11 tuna (ranging from 116 to 135 cm in fork length) were tagged and released from 2011 to 2013. Seven fish were successfully tracked to provide information on depth and temperature preferences as well as horizontal movements. The majority of the vertical movements (30.3%) of yellowfin tuna occurred in the 50-m depth range in mixed layers. The mean swimming depth was 74.4 m (±50.7 m) during the daytime and 94 m (±72.5 m) at nighttime, which was a contrast to the findings in other waters. The maximum diving depth was 1000 m, where the water temperature was approximately 4 °C. This value was similar to the measurements made by a CTD near a depth of 1000 m, where the water temperature was approximately 4.2 °C and the O2 level was 3.0 mg l−1 . One of the tuna travelled 190 NM (straight distance) in 37 days, with most of its horizontal movements (70.6%) occurring at temperatures that ranged from 26 to 28 °C, suggesting that yellowfin tuna have a preference for this temperature range throughout the period of PAST observation.

Archival tagging reveals swimming depth and ambient and peritoneal cavity temperature in age-0 Pacific bluefin tuna, Thunnus orientalis, off the southern coast of Japan

Although archival tags have been deployed in Thunnus since the early 1990s, few studies have placed such loggers on the small-size growth stage. In this study, Pacific bluefin tuna (PBT, Thunnus orientalis) 20–26.5 cm in fork length (FL) were fitted with archival tags and released off the southern coastal area of Japan from July to August in 2012, 2013, and 2014. Time-series data on swimming depth, ambient water temperature, and peritoneal cavity temperatures collected at 30-s intervals during 78–144 days were analyzed in 11 age-0 PBT. In August, the age-0 PBT spent 69.5 to 83.4% of their time within the mixed layer at mean temperatures between 27.6 and 28.3 °C, while previous studies reported that PBT with FL > 50 cm in the East China Sea are found most often in zones with temperatures between 14 and 19 °C. The thermal difference between the peritoneal cavity and ambient temperature was less than 1 °C for age-0 PBT in August, indicating that they were not in danger of overheating. The mean daytime swimming depths of age-0 PBT were significantly and positively correlated with the depth of the thermocline, especially from August to October. By focusing their swimming depths around the thermocline, the age-0 PBT potentially maximize the probability of encountering prey. There was a significant correlation between the mean nighttime depth and lunar illumination. The change in vertical distribution with the lunar cycle during nighttime is likely a form of predator avoidance.

Herring submesoscale dynamics through a major spawning wave: duration, abundance fluctuation, distribution, and schooling

In this study, a series of 17 repeated acoustic trawl surveys within a ca. 1500 km2 area covering the major spawning location for Norwegian spring-spawning herring (Clupea harengus) was conducted over a period of about 1 month. Local herring abundance increased from ca. 25 000 to 237 000 t, a significant proportion of the total spawning stock, in just 3 d and subsequently decreased to <30 000 t over the next 7 d. The abundance change was due to a single major spawning wave developing over the observation period, and an estimated 46 000 t of eggs and milt were deposited during the short time spent at the spawning ground. There was no difference in spawning activity between day and night, but herring were more associated with deep trenches and also generally stayed deeper in more dense schools during daylight than night-time. Schooling behaviour and distribution were also strongly state-dependent, and both school swimming depth and school height decreased as spawning progressed, as did the bottom depth where the schools were located. The massive herring spawning events seem to be low-risk adaptations to an environment where predators are abundant, with rapid spawning in huge aggregations as a strategy for predator swamping.

Swimming depth of dolphinfish (Coryphaena hippurus) associated and unassociated with fish aggregating devices

Swimming depth of dolphinfish (Coryphaena hippurus) associated and unassociated with fish aggregating devices

Sea lice infestation level alters salmon swimming depth in sea-cages

Hostparasite systems are often characterised by a co-evolutionary arms race, with avoidance behaviour being the first line of defence for hosts. In aquatic ecosystems, the rapid rise of fish farming has elevated host abundance, altering the context of hostparasite interactions. Behav- ioural defences in host fish may adapt to combat infection pressure in the captive environment. We tested whether farmed Atlantic salmon Salmo salar altered their swimming depth in response to the ectoparasitic sea louse Lepeophtheirus salmonis. Parasite loads were manipulated on individual fish, which were implanted with internal tags that recorded swimming depth. During daylight hours, salmon exhibited identical swimming depths irrespective of parasite load. However, fish with higher parasite loads (12�18 lice fish �1 ) swam deeper at nighttime, compared to fish with no or mod- erate parasite loads (0�6 lice fish �1 ). As infective sea louse copepodids are concentrated near the surface, our results suggest that the preference for deeper water in fish with higher parasite loads is an avoidance mechanism to prevent further infestation. Host behavioural responses to parasites are predicted to shift with changes to the system and artificial selection of host phenotypes; our study provides the first evidence of a parasite avoidance response in salmon held in sea-cages.

Comparison of the behavior of skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares) and bigeye (T. obesus) tuna associated with drifting FADs in the equatorial central Pacific Ocean

AbstractWe evaluated the behavior of skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares) and bigeye tuna (T. obesus) associated with drifting fish aggregating devices (FADs) in the equatorial central Pacific Ocean. A total of 30 skipjack [34.5–65.0 cm in fork length (FL)], 43 yellowfin (31.6–93.5 cm FL) and 32 bigeye tuna (33.5–85.5 cm FL) were tagged with coded transmitters and released near two drifting FADs. At one of the two FADs, we successfully monitored the behavior of all three species simultaneously. Several individuals remained around the same FAD for 10 or more days. Occasional excursions from the FAD were observed for all three species, some of which occurred concurrently for multiple individuals. The detection rate was higher during the daytime than the nighttime for all the species, and the detection rate for bigeye tuna was higher than for yellowfin or skipjack tuna. The swimming depth was deeper during the daytime than nighttime for all species. The fish usually remained shallower than 100 m, but occasionally dived to around 150 m or deeper, most often for bigeye and yellowfin tuna during the daytime. The swimming depth for skipjack tuna was shallower than that for bigeye and yellowfin tuna, although the difference was not large, and is probably not sufficient to allow the selective harvest of skipjack and yellowfin tuna by the purse seine fishery. From the detection rate of the signals, bigeye tuna is considered to be more vulnerable to the FAD sets than yellowfin and skipjack tuna.

Atlantic Sturgeon Spatial and Temporal Distribution in Minas Passage, Nova Scotia, Canada, a Region of Future Tidal Energy Extraction.

In the Bay of Fundy, Atlantic sturgeon from endangered and threatened populations in the USA and Canada migrate through Minas Passage to enter and leave Minas Basin. A total of 132 sub-adult and adult Atlantic sturgeon were tagged in Minas Basin during the summers of 2010–2014 using pressure measuring, uniquely coded, acoustic transmitters with a four or eight year life span. The aim of this study was to examine spatial and seasonal distribution of sturgeon in Minas Passage during 2010–2014 and test the hypothesis that, when present, Atlantic sturgeon were evenly distributed from north to south across Minas Passage. This information is important as tidal energy extraction using in-stream, hydrokinetic turbines is planned for only the northern portion of Minas Passage. Electronic tracking data from a total of 740 sturgeon days over four years demonstrated that Atlantic sturgeon used the southern portion of Minas Passage significantly more than the northern portion. Sturgeon moved through Minas Passage at depths mostly between 15 and 45 m (n = 10,116; mean = 31.47 m; SD = 14.88). Sturgeon mean swimming depth was not significantly related to bottom depth and in deeper regions they swam pelagically. Sturgeon predominately migrated inward through Minas Passage during spring, and outward during late summer-autumn. Sturgeon were not observed in Minas Passage during winter 2012–2013 when monitoring receivers were present. This information will enable the estimation of encounters of Atlantic sturgeon with in-stream hydrokinetic turbines.

Vertical distribution of saithe (Pollachius virens) aggregating around fish farms

Abstract Floating fish farm installations attract a number of marine species, probably because they provide both shelter and excess feed from the cages. Saithe are by far the most numerous fish visitors to fish farms on the Norwegian coast, and may gather in large numbers beneath the cages, but detailed knowledge of their swimming behaviour is limited. This study examined the vertical movements and distribution of saithe equipped with acoustic transmitters at 15 fish farms over a period of almost 2 years. The saithe aggregating around fish farms displayed behavioural patterns reported from saithe elsewhere; diel rhytms in vertical distribution, reduced activity level at night and seasonality in swimming depth. Typical residence depth was from 25 to 50 m in summer and 60 to 90 m during winter. However, an anomaly was observed, as fish moved 10–20 m closer to the surface during mid-winter. The reason for this is not known, but may be associated with the use of artificial light to illuminate the fish farm sea cages. The fish were usually distributed through ∼100 m of the water column. In 38% of the observations, there was no apparent diel vertical migration pattern, but 46% of the data showed fish either moved up or down during the daylight hours. Interindividual and intersite variability, in preferred night-resting depth, is a possible explanation for the differing vertical migratory patterns. Fish also moved away from fish farms in daytime (16% of all observations), probably to feed elsewhere. The results suggest that saithe establish core residence areas close to fish farms.

Olfaction Contributes to Pelagic Navigation in a Coastal Shark.

How animals navigate the constantly moving and visually uniform pelagic realm, often along straight paths between distant sites, is an enduring mystery. The mechanisms enabling pelagic navigation in cartilaginous fishes are particularly understudied. We used shoreward navigation by leopard sharks (Triakis semifasciata) as a model system to test whether olfaction contributes to pelagic navigation. Leopard sharks were captured alongshore, transported 9 km offshore, released, and acoustically tracked for approximately 4 h each until the transmitter released. Eleven sharks were rendered anosmic (nares occluded with cotton wool soaked in petroleum jelly); fifteen were sham controls. Mean swimming depth was 28.7 m. On average, tracks of control sharks ended 62.6% closer to shore, following relatively straight paths that were significantly directed over spatial scales exceeding 1600 m. In contrast, tracks of anosmic sharks ended 37.2% closer to shore, following significantly more tortuous paths that approximated correlated random walks. These results held after swimming paths were adjusted for current drift. This is the first study to demonstrate experimentally that olfaction contributes to pelagic navigation in sharks, likely mediated by chemical gradients as has been hypothesized for birds. Given the similarities between the fluid three-dimensional chemical atmosphere and ocean, further research comparing swimming and flying animals may lead to a unifying paradigm explaining their extraordinary navigational abilities.

Fine-scale 3-dimensional movement behaviour of silky sharks Carcharhinus falciformis associated with fish aggregating devices (FADs)

The silky shark Carcharhinus falciformis is the primary elasmobranch bycatch in the global tuna purse seine fishery using fish aggregating devices (FADs). Information on the associa- tive behaviour of this species with floating objects remains limited. Here the use of various elec- tronic tags provided important new insight into this behaviour. Thirty-eight juvenile silky sharks (69 to 116 cm total length; TL) were tagged with acoustic tags at 9 drifting FADs equipped with satellite-linked acoustic receivers in the western Indian Ocean (total monitoring = 154 d). Pres- ence/absence and swimming depth data were transmitted from the receivers. A subset of 17 indi- viduals was also fitted with pop-up satellite archival tags (PSATs; n = 13), or internal archival tags (n = 4). Behavioural data were successfully collected from 20 of the tagged sharks, covering a total of 300 d. Fine-scale movements of one individual were observed by active tracking, lasting 2 h 46 min. Sharks remained associated with the FAD where they were tagged for extended periods (2.84 to 30.60 d, mean = 15.69 d). Strong diel changes were observed in both FAD association and swimming depth. Typically, individuals moved away from FADs after sunset and returned later that night, then remained closely associated until the following evening. Vertical behaviour also changed around sunset, with sharks using fairly constant depths, >25 m, during the day and switching to rapid vertical movements during the night, with descents >250 m recorded. The actively tracked individual returned to a FAD from >1.2 km away. Long residence times and close association highlight the vulnerability of silky sharks to incidental capture in FAD fisheries.

Changes in host behaviour caused by immature larvae of the eye fluke: evidence supporting the predation suppression hypothesis

The manipulation of host behaviour by the not-fully-developed, immature larvae of trophically transmitted parasites is attracting growing interest. A theoretical model predicts that while facilitation of host predation risk is advantageous for fully developed parasite larvae, the immature ones should make hosts less vulnerable to the predators (predation suppression hypothesis). However, there is still little evidence of such manipulation by non-infective parasite stages. We tested whether immature trematode larvae of the eye fluke, Diplostomum pseudospathaceum, a common parasite of many freshwater fishes, enhance the anti-predatory responses of their host (Oncorhynchus mykiss). To test the predation suppression hypothesis, we experimentally infected young-of-the-year (YOY) rainbow trout and studied the influence of pre-infective metacercariae of the eye fluke on the anti-predator behaviour of the fish. Fish activity, depth preference and the ability to avoid simulated predation were evaluated in the experiments. Infected fish—harbouring a moderate number of immature metacercariae—were significantly less vulnerable to simulated predation (dip-net catch) and less active (horizontal move), but their swimming depth (vertical position) was not changed when compared with the control fish harbouring no larvae. Our findings suggest that immature larvae of D. pseudospathaceum induce changes in host behaviour that can protect them from predation, thereby supporting the predation suppression hypothesis and indicating that manipulations caused by immature parasites may play an important role in modulating predator–prey interactions.

The effect of temporal variation in sound exposure on swimming and foraging behaviour of captive zebrafish

Anthropogenic noise of variable temporal patterns is increasing in both marine and freshwater systems. Aquatic animals often rely on sounds for communication and orientation, which may therefore become more difficult. Predator–prey interactions may be affected by masking of auditory cues, sound-related disturbance or attentional interference. Here, we investigated the impact on both predator and prey for zebrafish, Danio rerio, preying on water fleas, Daphnia magna. We experimentally raised ambient sound levels in an aquarium and tested four sound conditions that varied in temporal pattern: continuous, fast and slow regular intermittent and irregular intermittent, which we compared with ambient sound levels with no extra exposure. We found no effects on water flea swimming speed or depth but there was an increasing number of individual zebrafish with an increased number of startle responses, especially to the intermittent sound treatments, which was also reflected in a significant increase in zebrafish swimming speed, but not in any change in zebrafish swimming depth. Discrimination in attacking edible water fleas or inedible duckweed particles was low for the zebrafish and unaffected by sound exposure, but foraging was affected in two ways: intermittent sounds delayed the initial acceleration response and all treatments caused a rise in handling error. These insights confirm that elevated sound levels, and especially intermittent conditions, may affect predator–prey interactions. Our results apply to laboratory conditions but call for outdoor studies that go beyond single-species effects. If acoustic impact of human activities extends to multiple species and their interactions, natural sound conditions may turn out to be important for the stability and dynamics of aquatic ecosystems.

Oversimplification of complex harvest modeling issues outlined in Welch et al. (2014)

In their paper, ‘Migration behavior of maturing sockeye (Oncorhynchus nerka) and Chinook salmon (O. tshawytscha) in Cook Inlet, Alaska, and implications for management,’ Welch et al. (Anim. Biotelem. 2:18, 2014) report data on migratory behavior and relative swimming depths of Chinook and sockeye salmon near the Eastside Setnet (ESSN) fishery, Cook Inlet, Alaska, using acoustically tagged fish and an anchored array of acoustic receivers. Using this information, they provide a model to estimate changes in Chinook and sockeye salmon harvests associated with potential regulatory changes affecting surface gillnet depths in this fishery. We are concerned that the modeling exercise paints an unrealistic picture of how simply changing gillnet dimensions would translate into a viable management approach to preserve or increase sockeye salmon harvests while minimizing catch of Chinook salmon. Much of this fishery occurs in very shallow water, and Cook Inlet tides range about 10 m with tidal current speeds reaching about 9 km hr−1. Model assumptions that gillnets in this dynamic environment were hanging vertically and that gillnets did not reach the bottom are not valid. Gillnets in this fishery billow in strong currents causing the lead lines at the bottom of the nets to rise in the water column, and an unknown but high fraction of all gillnets reach the bottom for some portion of each tide cycle. We believe further information and a more sophisticated analysis is needed to realistically model changes in Chinook and sockeye salmon harvests in relation to gillnet depths, and we are concerned about unintended consequences that may arise from unrealistic solutions based on limited data proposed in the regulatory arena.

Movements and oceanographic associations of bigeye tuna (Thunnus obesus) in the Northwest Atlantic

To address the lack of fisheries-independent information for Atlantic bigeye tuna (Thunnus obesus), we released 21 adults (131 ± 12 cm curved fork length) between 2008 and 2010 in the Sargasso Sea and Northwest Atlantic. Data from nine tags (range: 1–292 days; mean: 89 days) revealed (i) pronounced north–south movements in pelagic waters between areas including Georges Bank, Mid- and South Atlantic Bight, Caribbean Sea, and Brazilian shelf, (ii) a lack of east–west exchange, and (iii) a high-use area in the Hatteras Plain, centered southwest of Bermuda. Bigeye tuna occupied water masses of 2.7–28.2 °C and depths of 0–1280 m, with deeper depths in the daytime (daily mean ± standard deviation: 196 ± 92 m) than at nighttime (45 ± 29 m). Even though bigeye tuna are assumed to forage on the deep scattered layer during the day, generalized additive mixed models did not identify the deep scattered layer as an important predictor of daytime swimming depth. Model results highlight the importance of geographic location in influencing habitat utilization, and thus suggest the need for fisheries-independent monitoring in high-catch areas, such as the central and equatorial Atlantic.

Depth use and migratory behaviour of homing Atlantic salmon (Salmo salar) in Scottish coastal waters

AbstractKnowledge of swimming depths and migration routes of homing Atlantic salmon in open coastal zones is urgently required to inform decisions on managing the species, e.g. for the sustainable development of marine renewable energy. In May–June 2013, pop-up satellite tags programmed to detach from fish after 1–10 d were fitted to 50 adult salmon on the northern coast of Scotland. Most of the tags returned water depth recorded at regular intervals (n = 47) and gave a geographic location following detachment (n = 44). In general, salmon were found near the surface during the study, with the median number of records at 0–5 m depth ranging from 72 to 85%, depending on the extent of known potential systematic bias. Depth use varied among individuals (8–100% at 0–5 m) and cluster analysis suggested that the sample of fish could be split into two groups, representing different patterns of depth use. These clusters were also associated with pop-up location. There was a small but significant increase in recorded depth at night compared with during the day, contrasting with findings of salmon at sea in other contexts. The mean maximum dive depth was 64 m (range 13–118 m), of similar order to the likely available water column depth. These results suggest that salmon will potentially interact with man-made obstacles, e.g. renewable energy generators, throughout the water column and particularly in surface waters.

Low intensity light of different colours modifies Atlantic salmon depth use

Underwater anti-maturation-lights have recently been exploited to position sea-caged Atlantic salmon (Salmo salar L.) deeper at night in an effort to reduce infections by salmon lice (Lepeophtheirus salmonis) in surface layers. However, anti-maturation-light use is impermanent because lighting during decreasing day-lengths stimulates sexual maturation which is detrimental for fish welfare, growth and meat quality. The effects from lights on maturation are related to both light intensity and light spectrum. Here, we explored caged salmon depth use in response to lights of four low intensities (0.01, 0.10, 1.0 and 10.0μE as measured 1m from the lamps) and seven different colours (broadband white LED lamp and narrow spectrum violet, blue, green, yellow, red and deep red LED lamps). Triplicate sea cages (12×12m and 11m deep) holding approximately 5000 fish of 1.5kg were exposed to each light positioned at 10m depth for one night. Echo sounders registered fish vertical positioning on nights of light treatments and no light (control nights) before and after each light exposure. Results showed that submerged lights generally caused fish to maintain their day-time swimming depth near 10m (light depth) during the night, as opposed to the typical migration of salmon to upper cage depths at dusk observed on control nights. Quantities of fish staying deep decreased with lowered light intensity, but even 0.1μE had effects. All light colours, except deep red, significantly affected swimming depth, with a trend of increased effect at lower wavelength colours. Temperature stratification strengthened light effects when warmer water was near the lamps and weakened effects in the case of warmer water near the surface. This study opens up the potential of using low intensity lights at decreasing day-lengths that may not affect sexual maturation and remain suitable for guiding salmon away from surface waters rich in lice infective stages.

Flow Fields Inside Stocked Fish Cages and the Near Environment

This study explores the average flow field inside and around stocked Atlantic salmon (Salmo salar L.) fish cages. Laboratory tests and field measurements were conducted to study flow patterns around and through fish cages and the effect of fish on the water flow. Currents were measured around an empty and a stocked fish cage in a fjord to verify the results obtained from laboratory tests without fish and to study the effects of fish swimming in the cage. Fluorescein, a nontoxic, fluorescent dye, was released inside a stocked fish cage for visualization of three-dimensional flow patterns inside the cage. Atlantic salmon tend to form a torus shaped school and swim in a circular path, following the net during the daytime. Current measurements around an empty and a stocked fish cage show a strong influence of fish swimming in this circular pattern: while most of the oncoming water mass passes through the empty cage, significantly more water is pushed around the stocked fish cage. Dye experiments show that surface water inside stocked fish cages converges toward the center, where it sinks and spreads out of the cage at the depth of maximum biomass. In order to achieve a circular motion, fish must accelerate toward the center of the cage. This inward-directed force must be balanced by an outward force that pushes the water out of the cage, resulting in a low pressure area in the center of the rotational motion of the fish. Thus, water is pulled from above and below the fish swimming depth. Laboratory tests with empty cages agree well with field measurements around empty fish cages, and give a good starting point for further laboratory tests including the effect of fish-induced currents inside the cage to document the details of the flow patterns inside and adjacent to stocked fish cages. The results of such experiments can be used as benchmarks for numerical models to simulate the water flow in and around net pens, and model the oxygen supply and the spreading of wastes in the near wake of stocked fish farms.

Aggregations of bluefish Pomatomus saltatrix (L.) at Mediterranean coastal fish farms: seasonal presence, daily patterns and influence of farming activity

Bluefish, Pomatomus saltatrix (Linnaeus, 1766), is commonly observed close to Mediterranean open-sea fish farms. It usually preys on wild fish that are attracted to farms, but also on farmed fish by biting holes in sea cages net walls. In the current telemetry study, we found that the tagged bluefish stayed close to fish farms during spring and early summer. However, most of the tagged fish disappeared from the farms during autumn, when the sea water temperature dropped. When aggregating at farms, bluefish were present at deeper waters during day time, but moved closer to the surface during night time. In addition, periods when there was operational activity at the farms might influence on daily swimming depth of bluefish. Therefore, bluefish individuals seem to find an optimal foraging habitat around Mediterranean fish farms.

Behavior of skipjack tuna (Katsuwonus pelamis) associated with a drifting FAD monitored with ultrasonic transmitters in the equatorial central Pacific Ocean

The behavior of skipjack tuna Katsuwonus pelamis released at a drifting fish aggregating device (FAD) in the equatorial central Pacific Ocean was investigated using ultrasonic transmitters. We conducted two types of field observations: one to track a single fish using a continuous transmitter, and the other to simultaneously monitor multiple individuals with coded transmitters. In the first examination, the behavior of one individual (fork length (FL) of 65.2cm) was monitored when the fish was both near and away from the FAD. In the second examination, the behaviors of 14 individuals (FL between 36.0 and 64.0cm) were monitored only when these were associated with the FAD. The behaviors of the fish were monitored 82.0 and 154.5h using continuous and coded transmitters, respectively. The fish monitored with a continuous transmitter made several excursions from the FAD (maximum distance of approximately 9700m) during the monitoring period. The swimming depth during daytime was deeper than that observed during nighttime, and this difference was markedly more obvious when the fish was away from the FAD. Additionally, the daytime swimming depth was deeper when the fish was away from the FAD. The swimming speed of the fish monitored with a continuous transmitter was usually less than 3KT and was higher during daytime compared with nighttime. The fish monitored with coded transmitters occasionally left the FAD, particularly during nighttime, partly demonstrated diurnal vertical movements, and were mainly distributed in the mixed layer or upper part of the thermocline. In addition, the results showed a synchronicity in the vertical movements of two or more fish. This study indicated a clear difference between the on-FAD and the off-FAD vertical movements, occasional excursions from the FAD, and diurnal movements of the fish, especially when away from the FAD.

Behavioral changes of zebrafish according to cisplatin-induced toxicity of the balance system

Zebrafish are commonly used as experimental animals in otolaryngology studies. However, the behavioral characteristics of these fish are not well known, especially those related to the vestibular system. The goal of this study was to evaluate behavioral changes in zebrafish due to toxicity in the balance system. Zebrafish were exposed to 1000 μM cisplatin for 6 h. We, then, periodically monitored swimming depth, total swimming distance, peak swimming velocity, and mean swimming velocity of the fish for approximately 21 days. Total swimming distance (p < 0.0001), peak swimming velocity (p = 0.0063), and mean swimming velocity (p < 0.0001) in the cisplatin-administered group were significantly decreased when compared with control fish. Our findings demonstrate that cisplatin can alter the locomotion behavior of zebrafish.