Externally attached radio transmitters do not affect the parental care behaviour of rock bass

Turning, pectoral fin and caudal fin rates and time spent on the nest of male rock bass Ambloplites rupestris , engaged in parental care, were not affected after the attachment of external radio transmitters. Reproductive success was similar between treatment and control fish. Micro external radio transmitters can be used on small fishes for studying parental care duration and post-care movement without altering their behaviour.     

Can We Accurately Characterize Wildlife Resource Use When Telemetry Data Are Imprecise?

ABSTRACT Telemetry data have been widely used to quantify wildlife habitat relationships despite the fact that these data are inherently imprecise. All telemetry data have positional error, and failure to account for that error can lead to incorrect predictions of wildlife resource use. Several techniques have been used to account for positional error in wildlife studies. These techniques have been described in the literature, but their ability to accurately characterize wildlife resource use has never been tested. We evaluated the performance of techniques commonly used for incorporating telemetry error into studies of wildlife resource use. Our evaluation was based on imprecise telemetry data (mean telemetry error = 174 m, SD = 130 m) typical of field-based studies. We tested 5 techniques in 10 virtual environments and in one real-world environment for categorical (i.e., habitat types) and continuous (i.e., distances or elevations) rasters. Technique accuracy varied by patch size for the categorical rasters, with higher accuracy as patch size increased. At the smallest patch size (1 ha), the technique that ignores error performed best on categorical data (0.31 and 0.30 accuracy for virtual and real data, respectively); however, as patch size increased the bivariate-weighted technique performed better (0.56 accuracy at patch sizes >31 ha) and achieved complete accuracy (i.e., 1.00 accuracy) at smaller patch sizes (472 ha and 1,522 ha for virtual and real data, respectively) than any other technique. We quantified the accuracy of the continuous covariates using the mean absolute difference (MAD) in covariate value between true and estimated locations. We found that average MAD varied between 104 m (ignore telemetry error) and 140 m (rescale the covariate data) for our continuous covariate surfaces across virtual and real data sets. Techniques that rescale continuous covariate data or use a zonal mean on values within a telemetry error polygon were significantly less accurate than other techniques. Although the technique that ignored telemetry error performed best on categorical rasters with smaller average patch sizes (i.e., ≤31 ha) and on continuous rasters in our study, accuracy was so low that the utility of using point-based approaches for quantifying resource use is questionable when telemetry data are imprecise, particularly for small-patch habitat relationships.     

An acoustic telemetry study of seabream (Sparus aurata L.): first results on activity rhythm,effects of environmental variables and space utilization

The movements of seabream (Sparus aurata L) were recorded in two earthen ponds (250 m² and 400 m²) by tracking fish tagged with miniature acoustic transmitters. Five seabreams, 500 g in weight, were tracked for periods of four or five days. Fish positions were recorded continuously using an acoustic telemetry system. Each of the five tagged seabreams were tracked individually. Two fishes were released schooled with numerous other individuals, two others were released in isolation and one was grouped with three other individuals.The schooled seabreams were more active in general and, in the large school they were diurnal; isolated fishes however, were more active at night. Temperature influences significantly and progressively the fish activity. Activity decreases at night and increases during daylight. Oxygen saturation also influences swimming activity with a general positive relationship.The horizontal distribution of this species was not uniform. Its resting area was generally located around some particular landmarks such as inlet or outlet pipes in the ponds. No feverish feeding competition was observed between individuals of the same school. The feeding area was cleaned rapidly, in less than 10 minutes, without subsequent returns from the resting area to the feeding area.

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Résumé Les déplacements de la daurade (Sparus aurata L.) ont été enregistrés dans deux bassins en terre (250 m² et 400 m²) en suivant des poissons marqués avec des émetteurs acoustiques miniaturisés. Cinq daurades d'un poids individuel de 500 g furent suivies durant des périodes de 4 ou 5 jours. Les positions des poissons ont été enregistrées en continu avec un systéme de télémétrie acoustique. Chacun des cinq poissons marqués fut suivi individuellement. Deux poissons furent regroupés avec de nombreux autres individus, deux autres furent laissés seuls et le dernier fut mis avec trois autres individus.Les daurades groupées étaient en général plus actives et, en grand banc, étaient diurnes; les poissons isolés étaient toutefois plus actifs durant la nuit. La température influence significativement et progressivement l'activité des poissons. L'activité décroît durant la nuit et augmente pendant le jour. Le pourcentage de saturation en oxygéne agit aussi, de façon positive, sur l'activité de nage.La distribution horizontale de cette espéce n'est pas uniforme. Son aire de repos est généralement localisée dans quelques zones particuliéres comme les arrivées et les sorties d'eau. Aucune compétition alimentaire fébrile n'a été observée entre les individus d'un même banc. L'aire de nourrissage est rapidement nettoyée, en moins de 10 minutes, sans retours ultérieurs depuis la zone de repos jusqu' à la zone de nourrissage.

     

Remote monitoring of parental incubation conditions in the greater sandhill crane

To monitor incubation conditions in nests of greater sandhill cranes, a radiotrans-mitting egg was built using six temperature sensors, a position sensor, and a light sensor. Sensor readings were received, along with time of observations, and stored in a computer. The egg was used to monitor incubation in nests of six pairs of cranes during 1987 and 1988. Ambient temperature was also measured. Analysis of covariance (ANCOVA) was used to relate highest egg temperature, core egg temperature, and lowest egg temperature to ambient temperature, time since the egg was last turned, and time since the beginning of incubation. Ambient temperature had the greatest effect on egg temperature (P < 0.0001), followed by the time since the beginning of incubation and time since the egg was last turned. Pair effect, the class variable in the ANCOVA, was also very significant (P < 0.0001). A nine-term Fourier series was used to estimate the average core egg temperature versus time of day and was found to fit the data well (r² = 0.94). The Fourier series will be used to run a mechanical incubator to simulate natural incubation conditions for cranes. © 1995 Wiley-Liss, Inc.     

SATELLITE-MONITORED MOVEMENTS AND DIVE BEHAVIOR OF A BOTTLENOSE DOLPHIN (TURSIOPS TRUNCATUS) IN TAMPA BAY, FLORIDA

An adult, female bottlenose dolphin ( Tursiops trucncatus ) was radio tagged and monitored via satellite-based Argos receivers for 25 d from 28 June to 23 July 1990, in Tampa Bay, Florida. A total of 794 transmissions were obtained during 106 satellite passes. A mean of 3.9 (SE = 0.24) locations/day were determined by Service Argos and showed the animal remained in the bay, usually close to the southeastern shore. The dolphin moved at least 581 km at a minimum mean speed of 1.2 (SE = 0.1) km/h. Data from 63, 922 dives were recorded. The animal spent an average of 87.1 (SE = 0.6)% of the time submerged, with a mean dive duration of 25.8 (SE = 0.5) sec. Mean dive duration differed significantly between four periods of the day, as did the mean percent of time spent submerged. During the early morning the animal spent more time at the surface, averaged shorter dives, and was submerged less than other times of day. This is the first study to demonstrate die1 dive cycles in a bottlenose dolphin. Four months after tag loss, the dolphin was photographed with no evidence of necrosis or disfigurement of the dorsal fin. Satellite telemetry was demonstrated as an effective means of documenting the movements and dive behavior of a small inshore cetacean.     

Fluctuation of body temperature and cuckoo brood parasitism

Body temperatures of 11 bird species, including cuckoos, were measured in an artificial meteorological room. Ratios of change in body temperature to that in air temperature were thereby obtained for each species. Cuckoos demonstrate a remarkably high value, indicating a particularly low ability to regulate body temperature. Viewed in this light, the cuckoo's parasitic behavior is very likely an adaptation to overcome a physiological disadvantage. This in turn might be expected to reinforce delay in evolution of temperature homeostasis.     

Behavioural thermoregulation and homing by spring chinook salmon, Oncorhynchus tshawytscha (Walbaum), in the Yakima River

Temperature-sensitive radio transmitters were employed to study the patterns of behavioural thermoregulation, habitat preference and movement of 19 adult spring chinook salmon, Oncurhynchus tshawytscha (Walbaum), in the Yakima River. During the 4 months prior to spawning, fish maintained an average internal temperature 2.5°C below ambient river temperature. This represented a 12 to 20% decrease in basal metabolic demand or a saving of 17.3 to 29.9 calkg⁻¹ h⁻¹. Fish were most commonly associated with islands, pools, and rock out-croppings along stream banks. Homing behaviour appeared to be modified to optimize temperature regimes and energy conservation. As the time of spawning approached, fish left thermal refuges and migrated to spawning grounds upstream and downstream of refuge areas. Although spring chinook salmon residing within cool-water refuges may be capable of mitigating sub-lethal temperature effects, cool-water areas need to be abundant and available to the fish. The availability of suitable thermal refuges and appropriate holding habitat within mainstem rivers may affect long-term population survival.     

大型水母声学观测与评估技术研究进展

20世纪末以来,世界多个海域频繁出现大型水母暴发现象,对海洋生态系统、海洋渔业、沿海工业和滨海旅游业带来了巨大的灾难。为了研究大型水母生态习性,进而揭示其暴发机理并进行灾害的预警防治,近些年来国内外学者开展了大量的采用网具、目视、水下摄像、声学技术、航空影像等多种手段的大型水母监测调查工作,其中使用声学技术对大型水母进行资源评估和行为跟踪目前在欧美、日本、韩国等渔业发达国家已经开展了相关应用,在资源评估、运动学规律等研究中展现出较好的观测效果和应用潜力。目前我国在大型水母声学观测研究应用领域鲜有文献报道,通过介绍国际上利用声学技术对大型水母进行资源调查与评估、空间分布监测、运动规律等研究成果,为今后我国开展大型水母声学调查研究提供理论基础和科学依据。通过本文的分析,建议可以借鉴国际上采用科学鱼探仪、高分辨率成像声呐、声学信标等方法对大型水母进行监测调查和资源评估的研究成果,结合实际情况将声学技术逐步研究并应用到我国大型水母资源调查与评估、自然生态习性研究、重点水域大型水母动态监测预警中去,完善我国大型水母监测调查体系。     

Maximum tag to body size ratios for an endangered coho salmon (<Emphasis Type="Italic">O. kisutch</Emphasis>) stock based on physiology and performance

Many coho salmon stocks (Oncorhynchus kisutch) have been in decline during the past three decades. Canada’s most endangered salmon stock, the Thompson River coho salmon, is being studied extensively as managers attempt to reverse these population declines. Investigators are using acoustic telemetry to track the migratory behaviour and survival of the Thompson River (and other) coho salmon stocks. Coho salmon pre-smolts are relatively small compared with salmonid species that are typically studied using acoustic telemetry; therefore the identification of the appropriate sizes of fish and tags to use is critical. This study tested the effects of surgically implanting the three smallest sizes of acoustic tags currently available on the growth, survival, tag retention, swimming performance and physical condition of coho salmon pre-smolts for 300 days post-surgery. Maximum tag size to body size ratios ranged from 15–17% by fork length and 7–8% by mass for the three tag sizes (11 cm fork length for a 6 × 19 mm tag, 12.5 cm for a 7 × 19 mm tag, and 14 cm for a 9 × 21 mm tag). Based on our results, it is unlikely that coho salmon pre-smolts implanted with acoustic transmitters following these size guidelines would have poor survival in studies of freshwater migratory behaviour as a result of the surgery or the tag.