共查询到20条相似文献,搜索用时 15 毫秒
1.
K. M. Gorbatenko S. I. Kiyashko A. Ye. Lazhentsev V. A. Nadtochii A. B. Savin 《Russian Journal of Marine Biology》2008,34(7):497-506
The composition, abundance, diet and trophic status of zooplankton, bottom invertebrates, fish and nekton were analyzed based
on the data collected by the staff of the TINRO-Center during complex bottom trawl catches on the Bering Sea shelf in the
fall of 2004. The stomach contents of mass fish species were analyzed and the nitrogen and carbon isotopic composition of
36 mass species of plankton, benthos, nekton and nektobenthos, which together make up the basis of pelagic and bottom communities,
was determined. It was found that zooplankton noticeably differ from benthic invertebrates in carbon isotopic composition:
δ13C values in zooplankton varied from −20.3‰ to −17.9‰; in benthos—from −17.5‰to −13.0‰; and in fish—from −19.2‰ (juvenile walleye
pollock) to −15.3‰ (saffron cod). The levels of 13C isotope in the tissues of fish depended mostly on the share of pelagic or benthic animals in their diet. δ15N values in the studied species ranged from 8.6‰ (in sea urchins) to 17.2‰ (in large Pacific cods), which corresponds to a
trophic level of 2.8. Obviously the δ15N values reflect the degree of predation and generally show the ratio of primary, secondary and tertiary consumers in a fish’s
diet. Trophic interactions manifest a high degree of interdependence between benthic and pelagic communities (even without
taking into account such lower components of the food web as phytoplankton, bacteria, and protozoa) occurring in most nektonic
species that depend on both bottom and pelagic food. 相似文献
2.
D. S. Pavlov V. V. Kostin I. V. Nechaev N. I. Shindavina V. Ya. Nikandrov 《Journal of Ichthyology》2009,49(11):1081-1091
The social status of hatchery-reared juveniles of Atlantic salmon Salmo salar at the age of 11–19 months in conditions of lack of shelters was investigated experimentally. It was demonstrated that biochemical
differentiation in such juveniles begins at the age of 13 months—one month before the first differences in the social status
of fish and four months prior to the beginning of smoltification. The dominants occupy bottom areas with shelters and extrude
the subordinates to the water column. The subordinates undergo smoltification or die from aggression of the dominants. Concentrations
of dopamine, noradrenalin, and of their metabolites in the brain of fish in the beginning of smoltification were higher in
the dominants and, by the end of smoltification, were higher in smolts. The social behavior of fish is considered to be one
of the ethological mechanisms of differentiation of salmon juveniles into smolts and parr. 相似文献
3.
Yannis P. Papastamatiou Brad M. Wetherbee John O’Sullivan Gwen D. Goodmanlowe Christopher G. Lowe 《Environmental Biology of Fishes》2010,88(4):361-368
The Cookiecutter Shark (Isistius brasiliensis) is an ecto-parasitic predator of numerous large pelagic fish and mammals. However, little is known of its foraging ecology
due to its elusive foraging tactics in the pelagic environment. We used bite scar patterns on pelagic fishes landed at the
Honolulu Fish Auction to assess some of the Cookiecutter Shark foraging habits. Swordfish (Xiphias gladius) had the greatest percentage of bites (87.9 ± 25.0% of individuals had healed scars) followed by Opah (Lampris guttatus, 33.0 ± 8.3% of individuals). Most fish with scars only had one Cookiecutter Shark bite per individual with the exception
of Swordfish, which often had >5 bites per individual. Furthermore, Swordfish had a higher proportion of healed bite scars
meaning they had been attacked while free-swimming. Seasonal changes in the probability of hooked fish being bitten by sharks
were apparent for Swordfish, Bigeye Tuna and Opah. Based on bite scar diameter, larger Cookiecutter Sharks may preferentially
attack Swordfish rather than the other species of pelagic fish. When taken in conjunction with diving behavior of pelagic
fish, and fishing depths, the results add further support to the hypothesis that Cookiecutter Sharks perform diel vertical
migrations. 相似文献
4.
Aggressive behavior of hatchery-reared juvenile Black Sea brown trout Salmo trutta labrax at the age of 5.5–6.0 months is investigated. Shortage of suitable territory leads to the separation of the fish into two spatial groups: demersal and pelagic. During the process of spatial differentiation of the fish, the individuals that have not selected permanent habitats (demersal or pelagic) are characterized by the highest aggression level. The duration of the formation of stable spatial differentiation of the fish depends on the stocking density. At a low stocking density (10–45 fish/m2), spatial differentiation is established by the beginning of the second day after the transfer of the fish to new conditions; at a high stocking density (182 fish/m2), it is established approximately by the seventh day. Following the establishment of the (secondary) spatial groups, aggressive acts are registered mainly between the individuals from the same spatial group. A role of aggressive behavior in intrapopulation differentiation of brown trout is discussed. 相似文献
5.
Ovaries of four flatfish species—Liopsetta pinnifasciata, Pleuronectes obscurus, Pleuronectes yokohamae, and Glyptocephalus stelleri, as well as of Far Eastern navaga Eleginus gracilis and rudd Tribolodon brandtii caught in Peter the Great Bay of the Sea of Japan in prespawning and/or spawning periods were studied. Under conditions of
anthropogenic pollution of the bay, the state of fish ovaries is determined by several factors, such as migration activity,
mode of life (bottom or pelagic), and the degree of sites pollution where females stayed in the period of the vitellogenous
growth of oocytes. The pollution of the bay exerts the most damaging effect on the reproductive system of shallow species
of flatfish—L. pinnifasciata and P. obscurus—that do not perform far migrations and throughout their life stay in the zone exposed to toxicants. In navaga Eleginus gracilis and flatfish P. yokohamae, and G. stelleri that perform seasonal migrations, no damages of ovaries were found. 相似文献
6.
A. I. Markevich 《Journal of Ichthyology》2011,51(7):543-550
Territorial behavior of males of masked greenling Hexagrammos octogrammus guarding the nest site with eggs until hatching of embryos in the aquarium is studied based on visual observations and videorecording.
Formation of defensed territory around the nest and dynamics of aggressive contacts between the guarding male, conspecific
individuals, and other fish species are described. Factors determining the shape of the nesting territory, as well as the
features of behavior of masked greenling in the aquarium in comparison to behavior of this species in natural conditions,
are discussed. 相似文献
7.
Experiments carried out on underyearlings of four fish species—roach Rutilus rutilus, carp Cyprinus carpio, bream Abramis brama, and perch Perca fluviatilis—at illumination of 200–300 lx showed that the specimens with negative type of rheoreaction move downstream mainly (47–93%)
in the active form, with their heads downstream, and rarer (3–37%) in the active-passive form, with their tails downstream.
Increase of motivation for downstream movement caused by starvation leads to a higher part of fish with an active form of
movement and to greater speed of movement of underyearlings. Active downstream movement is a manifestation of rheoreaction. 相似文献
8.
Masanori Kohda Kenta Sasaki Yoichi Sakai Nobuhiro Ohnishi Kazunori Matsumoto 《Ichthyological Research》2005,52(4):406-409
Female choice of mates versus sites was studied in a wrasse, Cirrhilabrus temminckii. Males had territories within a restricted area on a rocky slope at which females visited and pair-spawned pelagic gametes.
Females visited several males or territories before spawning, suggesting the opportunity of female choice. Of the four characteristics
of territorial males examined—body size, ratio of pelvic fin length to body size, courtship, frequency and territory depth—only
territory depth was significantly correlated with daily mating success of males. The former three male characters were not
related to territory depth. These results suggest that female C. temminckii chooses deep sites rather than specific mates in mating. 相似文献
9.
Morphological and behavioral traits of Rasbora paviei from river and lake environments are studied. For investigations, the fish were caught from the middle reaches of the Cai
River and from the inshore zone of the Kam Lam Reservoir (Khanh Hoa Province, Central Vietnam). Phenotypic differences are
found in river and lake fish groups. Experimentally, differences in tactics and efficiency of defensive behavior are found
in specimens from different habitats in the presence of a predator—Lepisosteus sp. (Lepisosteidae). In river specimens of Rasbora, the defensive reaction is more efficient in comparison with specimens from the reservoir. The river specimens of Rasbora used predominantly the tactics of group defense from the predator and stayed in a school longer than the lake specimens. 相似文献
10.
Leila M. Porter Sarah M. Sterr Paul A. Garber 《International journal of primatology》2007,28(5):1035-1058
We studied the diet, habitat use, and ranging behavior of 1 group of Callimico goeldii (callimicos) over 12 mo in northwestern Bolivia. The group’s diet was comprised of fungi (39%), fruits (31%), arthropods
(14%), exudates (14%), and other matter (2%). Callimicos concentrated their ranging activities in secondary forest (50%),
primary forest with dense understory (30%), and bamboo (17%) habitats. The group’s total home range was 114 ha; on average
they used 38.4 ha/ mo and had a day range of 925 m. Monthly average day ranges—but not monthly home ranges—increased as frugivory
declined, suggesting that subjects foraged on fungi and exudates by rechecking resources within a core area, making their
day ranges longer than during months when they concentrated on fruit resources. The callimicos formed polyspecific associations
with tamarins (Saguinus labiatus and S. fuscicollis) during 81% of observations. Day ranges increased in months with higher association rates which appears to result from the
callimicos using a broader set of habitats when with tamarins than when alone. The ranging pattern of callimicos appears to
be influenced primarily by 3 factors: their seasonal shift in diet requires that they forage in a variety of habitats across
the year; their depletion of resources causes them to shift their core area over time; and their lack of territorial behavior
eliminates the need to patrol boundaries as part of their daily movement. As a result, callimicos differ from many other callitrichids
in their low ratio of day range length to home range size. 相似文献
11.
The pleustonic hydrozoan, Velella velella, occurs throughout tropical to cold-temperate oceans of the world and sometimes are stranded in masses along hundreds of kilometers of beaches. In June 2009, we encountered algal rafts in the Celtic Sea containing many V. velella that we immediately preserved for gut content analysis. Available prey were enumerated from raft-associated fauna and zooplankton sampled nearby. The identifiable prey (331) in V. velella comprised 78% raft-associated prey (primarily harpacticoid copepods, cumaceans, small fish) and 22% pelagic prey (calanoid copepods, barnacle nauplii, fish eggs). Comparison of ingested with available prey showed selection for fish eggs and small fish, among others; therefore, the null hypothesis, that V. velella consumed all available prey equally, was rejected. Transport by wind and water concentrate Velella spp. in convergences with algal rafts, which suggests that they are important predators of raft—as well as pelagic fauna. A visual survey in September 2004 across the Celtic Sea and beach-stranding data show that V. velella is very abundant in Irish waters at times. Its circumpolar abundance, consumption of pelagic prey and production from symbiotic zooxanthellae, and mass deposition on beaches suggest that V. velella is important in open-ocean carbon cycling and in transport of pelagic production to landmasses. 相似文献
12.
Little is known about species composition, distribution, and abundance of pelagic fish in the U.S. portion of the Beaufort
Sea continental shelf and slope. To inventory the community and describe pelagic fish distributions relative to water characteristics,
a systematic survey was conducted in August 2008. Acoustics (38 kHz), midwater trawling, and CTD casts were used to sample
water depths from 20 to 500 m. Age-1+ polar cod (Boreogadus saida) was the dominant fish species, with peak densities of 155,000 # ha−1 at bottom depths of 100–350 m. Age-0 fish (polar cod, sculpin (Cottidae family), and eelblenny (Lumpenus sp.)), dominated the pelagic biomass at bottom depths between 20 and 75 m, with peak densities of 160,000 # ha−1, but were also found in surface waters at bottom depths >75 m. Age-1+ polar cod were associated with cold, saline waters
likely of Chukchi Sea origin and mirrored published foraging distributions for beluga whales (Delphinapterus leucas). Conversely, age-0 fish were found in warm, fresher water, likely of ice melt and/or riverine origin, throughout the study
area. This study provides a necessary baseline for the development of Arctic assessment surveys and management plans for polar
cod. 相似文献
13.
An original behavioral test was used to study the effect of opioid substances on the thresholds of nociceptive responses to
pain stimuli—a series of electric impulses applied to nerve endings of the caudal fin—in the common carp (Cyprinus carpio). The substances tested included tramadol (μ-agonist of opioid receptors), DADLE (δ-agonist), and U-50488 (κ-agonist) injected
intramuscularly in concentrations 10–100 nmol/g of body weight. Raised thresholds of sensitivity to the pain stimulus were
observed in the studied fish 5 to 15 min after the injection. The degree of analgesia and the rate of its increase varied
depending on the dose. The total duration of analgesia was 40 to 90 min and depended on the concentration of the injected
substance. It was observed in some experiments that the analgesic effect of tramadol (the most efficient of the analgesics
used) could last longer than 4 h. The analgesic effect of opioids was not detected in experiments where they were applied
together with naloxone, an antagonist of opioids. Decreased motor response to pain stimuli after injections of analgesics
was not caused by the immobilization of the animal, because the tested fish individuals released into an aquarium demonstrated
normal swimming and their usual behavior. We concluded that the systems of opioid nociceptive regulation function similarly
in fish and land vertebrates. This regulation can play an important role in defense behavior and in other behaviors in fish. 相似文献
14.
João Alves de Lima Filho Jhany Martins Rafael Arruda Lucélia Nobre Carvalho 《Biotropica》2012,44(4):512-520
The breathing behavior of the jeju fish Hoplerythrinus unitaeniatus has been the focus of several studies in recent decades. Few of these studies, however, have described how the fish's air breathing functions in natural environments. We examined changes in the behavior of H. unitaeniatus during daily variations in the dissolved‐oxygen (DO) content of the water in Amazonian streams. We recorded the mean time intervals between instances when the fish breached the water surface to take in atmospheric air and the variation in the DO concentrations. We also observed the number of individual fish that breached the surface together as well as their territory‐forming behavior. We recorded the individual and collective anti‐predator strategies in the presence of a potential predator, experimentally testing the capacity of H. unitaeniatus to recognize the shape of a predator. The results indicated that as the DO concentration decreased, the individuals of H. unitaeniatus tended to breach the water surface at shorter time intervals, which increased their exposure to predators. To minimize the risks from this longer exposure time, the species tends to adopt anti‐predator strategies individually or as a group. In well‐lit locations, the fish recognized the predator's silhouette, left their territory and took a longer time to return. We provide an original contribution to the understanding of the anti‐predatory tactics of the species by describing the behavior of group formation and territory definition as a tool to maximize efficiency in the defense against predators, a behavior that until now was an unknown strategy for this species. 相似文献
15.
Fabián A. Vanella Daniel A. Fernández M. Carolina Romero Jorge Calvo 《Polar Biology》2007,30(4):449-457
The fish fauna associated with a Macrocystis pyrifera forest and the effects of the canopy removal on this fauna were studied in the Beagle Channel, Tierra del Fuego. Seasonal
changes and differences in the fish communities that inhabit the canopy and the holdfast were also studied. Two patches of
kelp forest separated by 200 m were selected. In one, the canopy was removed periodically while the other was used as a control.
Samples were collected seasonally, from autumn 1999 to 2001. Fish fauna in the water column was sampled using trammel nets
and holdfast fish fauna was sampled by removing the complete holdfast. Different assemblages of fish species were captured
in the water column (surface and bottom) and in the holdfast. In the former there were mainly pelagic and benthopelagic species
and the latter predominantly demersal species. The principal effect of the canopy removal was a drop in the abundance (and
total weight) of Paranotothenia magellanica (doradito), the species with the strongest relationship with the canopy, principally at the surface of the treated patch
probably due to a reduction in the availability of refuges. A high degree of seasonality was observed for fish species’ total
weight, abundance and diversity, with higher values in summer and autumn. Taking into account our data and available data
on kelp growth in the same locality, we suggest of cutting the kelp forest (preferably those farther away from the coast)
once a year in winter or early spring, in order to minimize impact on the fish community. 相似文献
16.
In comparison with other bathydraconids, all species of the genus Bathydraco are poorly known from an ecological perspective. The diet of juvenile Bathydraco marri Norman, 1938 was studied for the first time in specimens collected in the southwestern Ross Sea during summer 1998. Fish
were collected in a single otter trawl catch at 330–340 m depth. The stomach content analysis showed that this species fed
exclusively on crustaceans. Overall, 20 prey taxa were identified to genus or species level. Mysids, amphipods and copepods
were the most important prey in decreasing order of importance. Other prey, such as Euphausia superba, isopods and tanaids were eaten occasionally and in very small amounts. A multivariate analysis was applied to feeding data
to assess ontogenetic or sex-related changes in diet. No difference was detected between sexes, whereas diet of small and
large fish differed in some degree. An ontogenetic shift from small and pelagic crustaceans such as copepods to benthic–benthopelagic
prey such as amphipods and mysids was observed. Relating present results with published data on physiological characteristics
of B. marri, it was possible to infer their feeding behaviour and mode of life. Like other bathydraconids, this species appeared to be
an inactive and sluggish fish, which relied on more or less motile benthic or epibenthic prey adopting a “sit and wait” feeding
strategy. On the other hand, smaller fish seem to be more active, feeding also on pelagic prey such as copepods that can be
seasonally abundant, thus reducing the intraspecific competition for food. 相似文献
17.
18.
The occurrence of eggs, pelagic larvae and juveniles, and settled juveniles of the dragonetRepomucenus valenciennei in Tokyo Bay, Japan, were investigated by plankton net and bottom trawl surveys between September 1990 and September 1991.
Eggs, and pelagic larvae and juveniles appeared from April to November (spring to autumn), peaking in both spring and autumn.
From the temporal pattern of egg and pelagic fish occurrence, and pelagic duration reported elsewhere (ca. one month), settlement
could be predicted as occurring from late spring to autumn. However, settled juveniles appeared from August to December, with
an abrupt peak in November. Aging from daily increments in the otoliths of settled recruits in 1990 indicated that the latter
comprised individuals which had hatched between mid-September and early November (i.e. autumn cohort), implying that individuals
which had hatched in spring to summer (April to August) were not recruited. Benthic hypoxia occurs widely in Tokyo Bay, from
June to October each year, particularly in the northern part, which is the main nursery area ofR. valenciennei. The timing of dissolved oxygen recovery, and appearance of settled fish coincided closely (i.e. November), indicating that
summer hypoxic conditions prevented the settlement of the spring cohort and hence recruitment to the population. 相似文献
19.
Egor S. Zadereev Alexander P. Tolomeyev Anton V. Drobotov Anna Yu. Emeliyanova Mikhail V. Gubanov 《Aquatic Ecology》2010,44(3):531-539
The vertical distribution and abundance of Gammarus lacustris in the pelagic zone of two fishless meromictic lakes, L. Shira and L. Shunet, in Southern Siberia (Russia), was studied with
the underwater video recording system and using vertical hauls. In both lakes, during summer stratification, Gammarus was distributed non-homogenously, with a stable peak in the metalimnion. The average depth of Gammarus population in the pelagic zone was significantly correlated with the depth of the thermocline. Gammarus abundances obtained using vertical plankton hauls with net were quite comparable with those obtained from video records.
The peak abundance of Gammarus in the pelagic zone of the lakes observed with underwater video amounted up to 400 individuals m−2, while the peak animal densities in the metalimnion reached 50 ind. m−3. The data are compared with previously published abundances of Gammarus in the littoral of Lake Shira. Both littoral and pelagic can be equally important habitats for amphipods in meromictic lakes.
The absence of fish in the pelagic zone, high oxygen concentration, low water temperature, increased seston concentration,
elevated water density in the metalimnion and the anoxic hypolimnion can be the most probable combination of factors that
are responsible for the peak of Gammarus in the metalimnion of these lakes. 相似文献
20.
Long-term, remote monitoring of animals under natural conditions is essential for obtaining information on animal activity. Advances in biotelemetry have led to the construction of low-power accelerometers placed on Global Positioning System (GPS) collars. Such acceleration data from roe deer have not yet been classified to the various behavioral categories. Here, we determined the threshold values of such data for different behavioral categories. We equipped captive roe deer with Global Positioning System–Global System for Mobile Communications/dual-axis acceleration sensor neck collars and simultaneously measured their movement and observed their behavior. The difference between feeding and slow locomotion was significant on the x- but not the y-axis, and both of these two behavioral categories differed significantly from resting and fast locomotion. Specific thresholds for the behavioral categories—resting, feeding, and slow and fast locomotion—were established by recursive partitioning. We compared the behavior determined by these threshold values with observed behavior and found that 92% of the behavioral categories were correctly assigned. A comparison of our results with those of earlier studies showed that thresholds derived for one species cannot be directly applied to another species. We provide recommendations for the further development of acceleration sensors based on the results obtained in this study. 相似文献