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1.
The karyotype of the endemic Okhotsk Sea sculpin Myoxocephalus ochotensis Schmidt (Cottidae) from Odyan Bay was studied. The number and morphology of chromosomes were determined, 2n = 42 (2 metacentric, 20 subtelocentric, and 20 acrocentric chromosomes), NF = 44. Variability of chromosome number was not revealed; no difference between male and female karyotypes was found. The karyotype of the Okhotsk sculpin M. ochotensis was compared with karyotypes of the Far East Steller’s M. stelleri (Tilesius), snow M. brandti (Steindachner), and plain M. jaok (Cuvier) sculpins, and to the European shorthorn sculpin M. scorpius (Linnaeus) from White Sea. Their similarities and distinctions were shown.  相似文献   

2.
Feeding patterns of the great sculpin Myoxocephalus polyacanthocephalus in near-Kamchatka waters of the Sea of Okhotsk, the Bering Sea and Pacific Ocean are considered using materials collected during 1978–2002. This species of Cottidae is characterized by wide feeding spectra (over 150 nutritive objects); nonetheless, fishes (on average 61.1%) and Decapoda (20.0%) have the highest significance in its diet. The fishes include Alaska pollock Theragra chalcogramma (32.7% of food mass), flatfish Pleuronectidae (12.2%), and sculpins Cottidae (10.5%); Decapoda include crabs from the family Majidae (18.5%). Seasonal, local, interannual, and age-related changes in food composition of the great sculpin are considered. This species is a facultative ambuscade predator; it is characterized by wide feeding spectra that permits him to use a considerable range of food components. In the trophic system of near-Kamchatka regions, units that form the biomass of the great sculpin are selected.  相似文献   

3.
The food spectrum and seasonal dynamics of feeding of the stone sculpin Paracottus knerii in the littoral of southern Baikal is investigated. Altogether, 29 species of invertebrates are recorded. All year round, the bulk of food, similarly to other areas of the lake, consisted of amphipods; other groups of zoobenthos were represented insignificantly. The significance of particular amphipod species in the food of fish depended on their ecological and morphofunctional traits. The seasonal changes in the species composition and the ratio of food items in the food depended on life cycles of fish and on the migrations of zoobenthic organisms.  相似文献   

4.
A new cottid species,Icelus ecornis, is described on the basis of 31 specimens collected from 159–226 m in the southwestern Okhotsk Sea off Hokkaido, Japan. It is distinguished from all other members of the genusIcelus by the following combination of characters: no supraocular and parietal spines; short blunt nuchal spine; cirri absent from head and body, except for supraocular, parietal and nuchal regions; platelike scales of dorsal row bearing 6–10 long uniform spinules; tubular lateral line scales bearing small spines on dorsal and posterior margins; large oval black spot on first dorsal fin; 16–20 anal fin rays.  相似文献   

5.
Data on occurrence, spatial-bathymetric distribution, size-weight composition, size-sex structure, and food composition of butterfly sculpin Melletes papilio in the Sea of Okhotsk waters off the Kamchatka shores are given. This species is a relatively nonnumerous representative of fam. Cottidae with maximal length 42 cm and body weight to 960 g. In summer time, the species occurs practically over the whole study region at depths of 15 m to 285 m and water temperature near the bottom from ?0.9 to 10.7°C. However, the majority of individuals of this species occur within the depths range of 41–80 m in the cold intermediate water level at minimal positive (<2.0°C) and negative values of near-bottom water at sandy-silty grounds. The correlation between the harvesting depth and fish size has been analyzed. The variations of the feeding spectrum with growth of butterfly sculpin are described for the pre-Kamchatka waters of the Sea of Okhotsk.  相似文献   

6.
The food spectra, trophic statuses, and feeding interrelations of three most abundant benthic carnivorous fish species inhabiting the Shelikhov Bay—the Pacific cod Gadus macrocephalus, the great sculpin Myoxocephalus polyacanthocephalus, and the Okhotsk sculpin M. ochotensis—are considered based on materials collected during the complex survey of the RV Professor Kaganovsky of the TINRO-Center, in September 2004. It was found that these species were facultative predators with wide food spectra. The significance of prey objects in the diet of the Okhotsk sculpin was as follows: crustaceans, fish, and mollusks. Great sculpin and Pacific cod preyed mostly on fish, then on crustaceans, and mollusks. Pacific cod ate equal proportions of fish and decapods. All the species had age-related variability of diet. The potential competition of great sculpin and Okhotsk sculpin for food was mitigated by the difference in the depths of their ranges, as well as by morphological (body size) and behavioral peculiarities in the areas where their habitats overlapped, and in microecosystems. The most probable competition was among Pacific cod 30–60 cm long and Okhotsk sculpin 20–50 cm in length, as well as among cod and great sculpins of all sizes.  相似文献   

7.
This study deals with the karyotype of the flathead sculpin Megalocottus platycephalus platycephalus (Pallas, 1814) (family Cottidae) from Odyan Bay of the Sea of Okhotsk. The karyotype is stable: 2n = 42 (2 metacentric, 2 submeta-subtelocentric, 30 subtelocentric, and 8 acrocentric chromosomes), NF = 44 + 2. The nucleolar organizers (NOs) were identified using Ag-banding in the telomere parts of the short arms of two large subtelocentric chromosomes. Variations in the number of nucleolar organizer chromosomes and in the number of NO-staining blocks were found. Comparison of the karyotype of M. p. platycephalus with the karyotypes of previously studied species of the genus Myoxocephalus from the Sea of Japan and the Sea of Okhotsk revealed their significant similarity in the main features and difference in the number and localization of NORs.  相似文献   

8.
Journal of Ichthyology - In the waters of Primorye in the spring-summer period, the Okhotsk snailfish Liparis ochotensis is distributed in the depth range from 50 (minimum analyzed) to 741 m;...  相似文献   

9.
Journal of Ichthyology - Plastic and meristic characters, position of teeth on jaws, and coloration of Okhotsk Sea fringed sculpin Porocottus minutus endemic to the north part of the Sea of Okhotsk...  相似文献   

10.
11.
It may be expected that vertehral anomaties would reduer the viability and reproductive success of fish. In the present study. the relationship of vertebral defects to body mass. Iength, age, condition, gonadosomatic index and growth in fourhorn sculpin, Myoxocephalus quadricornis , in the Gulf of Bothnia was studied. There were no differences in growth between normal and defective lish, for either males or females. While normal and defectives males were similar in age and length. defective females were older and longer than normal females. Defective males and females had a significantly greater somatic mass that normal fish. However defective females may be later than in normal fish. Hence, vertebral defects do not necessarly reduce the reproductive potential of fourhorn sculpin.  相似文献   

12.
We have previously shown in rainbow trout (Oncorhynchus mykiss) that gastric distension induces an instantaneous alpha-adrenoceptor-mediated increase in the dorsal aortic blood pressure (P(da)), with no change in cardiac output (CO), gut blood flow (Q(cma)), or heart rate. To investigate if feeding habits affect these patterns and to compare the differences between gastric distension alone and feeding in the same experimental setting, we used the short-horn sculpin (Myoxocephalus scorpius), an inactive ambush predator with a capacity to eat large meals. An inflatable balloon was placed in the stomach of one group while another group was fed fish meat. When distending the stomach with a volume corresponding to a meal of 8-10% body weight, there is a profound and long-lasting increase in systemic (123 +/- 27%) and gastrointestinal (R(cma); 82 +/- 24%) vascular resistance, leading to an increase in P(da) (19%) without any change in CO or Q(cma). After force-feeding, there is a rapid transient increase in R(cma) (24 +/- 4%) and an even larger P(da) response (53%). There is also a subsequent increase in both CO (28 +/- 8%) and Q(cma) (27 +/- 9%) after 30 min. By 15 h, CO and Q(cma) increase further (41 +/- 11 and 63 +/- 14%, respectively), and this increase persists for up to 60 h. The increase in Q(cma) is mediated via both an increase in CO and a shunting of blood from the systemic circulation via a decrease in R(cma) (34 +/- 7%). In conclusion, the response to mechanical distension of the stomach is similar to what we have described in rainbow trout, and the postprandial gastrointestinal hyperemia is most likely chemically induced.  相似文献   

13.
A field study examined sound production in the pygmy sculpin Cottus paulus, a threatened species found only in Coldwater Spring (Coosa River drainage), Alabama where the study was conducted. Two distinct call types are made during both courtship and agonistic encounters: a single knock and a knock train. The duration of the knock train significantly differs between contexts, while the signal structure stays the same. Knock trains are longer when the intended audience is a female, while short and abrupt when intended for a male intruder.  相似文献   

14.
Vertebral defects in adult fourhorn sculpin were used to trace heavy metal pollution in the Gulf of Bothnia (Baltic Sea). From 1978 to 1984 a total of 9789 specimens from 22 localities were X-rayed and analysed for vertebral deformities, e.g., scoliosis, deformation and/or dislocation of individual vertebrae, etc. The frequency of fish with vertebral defects ranged between 4.3 and 39.7%, the highest frequencies being found in the vicinity of a metal ore smeltery (Rönnskärsverken) emitting heavy metals and arsenic. The possible influence of genetic factors, migration, sex, size, age and parasitic infections on the results are discussed and evaluated.  相似文献   

15.
Spawning of snowy sculpin in Peter the Great Bay begins in November and takes place at a depth of about 4–7 m. Males of this sculpin species guard their laid eggs. Larvae hatch in April. Final fecundity is attained at ovary maturity stages IV–V.  相似文献   

16.
Synopsis During reproduction maleCottus bairdi defend cavities beneath stones and perform defense and reproductive displays. Using a geophone to detect substrate vibrations under dark conditions (infrared viewing), we recorded three types of sounds. Knocks are produced during head nods and an acoustically similar sound is produced when the fish slaps the head to the substrate. A third sound, the drum roll appears to be a fast repetition of several knocks followed by a head slap. We argue that these signals traveling through the substrate are of greater importance than sounds traveling through the water because (1) the substrate vibration attenuates at a much lesser rate than the water vibration and, (2) even near riffles, which generate much water vibration, the background noise in the substrate is low enough for the fish to detect such sounds.  相似文献   

17.
1. We examined the effects of prey abundance on patch selection by a benthic fish, the mottled sculpin ( Cottus bairdi ), in a fourth order, southern Appalachian stream (North Carolina, U.S.A.). This habitat is a mosaic of small (i.e. < 0.5 m2), relatively discrete patches.
2. Patches were characterized in terms of physical habitat variables, detritus (coarse particulate organic matter, CPOM) and macroinvertebrate abundance (number and biomass). We quantified patch selection by comparing the characteristics of patches utilized by sculpin with those of locally available patches. Locally available patches were selected using a constrained random sampling design (i.e. randomly selected within a 2 m radius from each fish). We also examined the relationship between macroinvertebrate abundance, CPOM and the physical characteristics of available patches.
3. Patches selected by sculpin contained significantly higher macroinvertebrate abundances (both number and biomass) than locally available patches in five out of six seasonal samples. Sculpin also occupied patches with significantly higher amounts of CPOM in three out of five seasonal samples. Patches utilized by sculpin, however, could not be consistently differentiated from locally available patches on the basis of physical variables. In addition, macroinvertebrate abundance was not consistently related to physical habitat variables or CPOM during the course of the study.
4. Our results suggest that sculpin are able to assess patch quality on the basis of prey abundance and select patches that potentially maximize energy gain. This behaviour may produce an increase in individual fitness, especially when prey distributions are not consistently related to habitat variables. Quantifying patch use in relation to prey abundance may help elucidate the causal factors determining habitat use by benthic fishes in other lotic systems.  相似文献   

18.
1. We examined the effects of prey abundance on patch selection by a benthic fish, the mottled sculpin ( Cottus bairdi ), in a fourth order, southern Appalachian stream (North Carolina, U.S.A.). This habitat is a mosaic of small (i.e. < 0.5 m2), relatively discrete patches.
2. Patches were characterized in terms of physical habitat variables, detritus (coarse particulate organic matter, CPOM) and macroinvertebrate abundance (number and biomass). We quantified patch selection by comparing the characteristics of patches utilized by sculpin with those of locally available patches. Locally available patches were selected using a constrained random sampling design (i.e. randomly selected within a 2 m radius from each fish). We also examined the relationship between macroinvertebrate abundance, CPOM and the physical characteristics of available patches.
3. Patches selected by sculpin contained significantly higher macroinvertebrate abundances (both number and biomass) than locally available patches in five out of six seasonal samples. Sculpin also occupied patches with significantly higher amounts of CPOM in three out of five seasonal samples. Patches utilized by sculpin, however, could not be consistently differentiated from locally available patches on the basis of physical variables. In addition, macroinvertebrate abundance was not consistently related to physical habitat variables or CPOM during the course of the study.
4. Our results suggest that sculpin are able to assess patch quality on the basis of prey abundance and select patches that potentially maximize energy gain. This behaviour may produce an increase in individual fitness, especially when prey distributions are not consistently related to habitat variables. Quantifying patch use in relation to prey abundance may help elucidate the causal factors determining habitat use by benthic fishes in other lotic systems.  相似文献   

19.
Data on the flathead sculpin Megalocottus platycephalus taeniopterus from different regions of Sakhalin are provided. Based on analysis of the morphological material, the estimates of taxonomically significant characters of the northern and southern subspecies are clarified. They include the relative length of the lower jaw, the extent of development of postorbital and occipital tubers, the coloration of pectoral fins, the shape of free ends of ventral fin rays, and their relative length and coloration in females. The habitats of M. platycephalus taeniopterus are considerably attributed to the desalinated sites of coastal waters. In the areas of eastern Sakhalin, its individuals stay in brackish water lakes and lagoons for a considerable part of their life; some individuals migrate to coastal waters for feeding in summer. Considerable differences are observed between populations in the life span, rate of growth, and the age of maturation of individuals. In the regions of eastern and western Sakhalin, the pattern of feeding of M. platycephalus taeniopterus differs considerably: in eastern regions, it is a clearly pronounced predator, and in western regions, it feeds mainly on invertebrates.  相似文献   

20.
Synopsis Mating success of males and its correlates were investigated in a natural population of the polygynous fluvial sculpinCottus nozawae. Furthermore, the female mate preference of this species was examined experimentally under alternative conditions for mating in a stream. The mating success of individual males (the number of females with which a male mated) ranged between 0 and 8 with a mean of 2.41 in 1983 and 2.52 in 1989, in a population of which the sex ratio was about 1 : 2 in both years, skewed toward females. Mainly due to the excess of nests without egg masses and the few nests with one egg mass, the distribution of male mating success did not fit a Poisson distribution, indicating its non-randomness. Male mating success was not correlated either with the size of the nest rocks or with the male size, suggesting that these two variables are not determinants of mating success. The mate choice experiments demonstrated that females of this species more frequently chose smaller males as mates whose nests already contained eggs than large males without eggs. Additionally, an analysis of stomach contents of guarding males suggested that the parental males ate their own eggs during egg guarding (filial-cannibalism). Based on these results and on a comparison of reproductive characteristics with congeneric species, it is suggested that one of the most important determinants for female mate choice inCottus species may be whether or not parental males are filial egg cannibals.  相似文献   

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