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1.
The growth and survival of larvae can be significantly enhanced through close association with patches of high prey concentration.
However, the taxis and kinesis responses used by larvae to locate and maintain residence in micro-patches remains poorly understood.
In this study, the behavioral responses of Pacific cod (Gadus macrocephalus) and walleye pollock (Theragra chalcogramma) larvae (45–100 dph) to light, prey scent, and prey were examined. Both species displayed an ontogenetic shift in response
to a horizontal light gradient, with small larvae (11–13 mm SL) exhibiting a positive phototaxis and large larvae (23–32 mm
SL) exhibiting a negative phototaxis. Whether this reversal is related to ontogenetically appropriate foraging cues or some
other aspect of the environment remains to be determined. Neither species displayed significant behavioral responsiveness
to the introduction of olfactory prey cues at either size. The aggregating (taxis) response of large larvae to introduction
of live prey was stronger than that of small larvae, possibly due to increased reaction distances and encounter rates. In
addition, both species exhibited a kinesis response of reducing the frequency of swimming bouts in response to introduction
of live prey. These results suggest that the scale of prey patchiness and the physical factors that determine patch encounter
rates are a significant determinant of larval growth and survival in the early feeding stages of marine fishes. 相似文献
2.
The juveniles of Kyphosus vaigiensis (Quoy and Gaimard 1825), collected from the Indian Ocean and Japanese waters, are described with some ontogenetic morphological changes based on
six specimens having 14 dorsal and 13 anal fin soft rays, 56–62 scales in a longitudinal row along the midbody, and 30–32
gill-rakers on the first gill-arch. The juveniles of K. vaigiensis smaller than ca. 42 mm in standard length (SL) have the proximal parts of the dorsal and anal fin soft-rayed portions covered
with small scales, and the single outer row of the upper jaw teeth consisting of incisor-like and conically pointed teeth,
the former with polycuspid tips differing from the specimens greater than ca. 68 mm SL. The holotype of Cantharus lineolatus Valenciennes 1830, 41.5 mm SL, was included here in the juveniles as K. vaigiensis. Therefore, K. vaigiensis is recognized as a senior synonym of C. lineolatus. 相似文献
3.
4.
Larvae and juveniles of the alepocephalid fishes, Leptoderma lubricum [26.9–69.0 mm in standard length (SL)] and Leptoderma retropinnum (21.1–67.2 mm SL), collected within 1–8 m of the seafloor in Suruga Bay, southern Japan, are described. They can be easily
distinguished from each other by the following adult-like characters: membrane morphology between the vertical fin rays and
procurrent caudal-fin rays (separated in L. lubricum vs. continuous in L. retropinnum), numbers of dorsal-fin rays (34–40 vs. 45–52) and anal-fin rays (50–57 vs. 65–72), and caudal peduncle length (11.7–13.4%
SL vs. 4.5–5.9% SL), in addition to several other body proportional differences. Unique characters in the larval stages of
Leptoderma include a translucent occipital region, horizontally elongated eye, and head below the upper margin of the orbit and abdominal
cavity densely covered by melanophores, ontogeny being characterized by the acquisition of general adult characters to the
postflexion stage, indistinct transformation, and the retention of few larval characters until almost the end of the juvenile
stage, as in other known alepocephalids. In addition to the near-bottom larval and juvenile collections of both species, the
occurrences of benthic or near-bottom taxa, including Harpacticoida, in their gut contents confirmed the early life history
dependence of the former on the near-bottom. 相似文献
5.
A new species of opisthoproctid, Dolichopteryx pseudolongipes, is described on the basis of three specimens (48.7–79.9 mm in standard length: SL) collected from the eastern Pacific Ocean.
This species is characterized by small tubular eyes (diameter 2.7–3.9% SL), presence of an adipose fin, anal fin base originating
under the dorsal fin base, relatively short predorsal (73.3–73.8% SL), prepelvic (64.3–67.9% SL), preanal (77.4–80.1% SL),
and preanus (71.5–75.7% SL) lengths; 31–33 (=9–10 + 22–24) gill rakers and 43–45 vertebrae. Although D. pseudolongipes had previously been confused with Dolichopteryx longipes, many differences between the species are apparent [e.g., adipose fin absent, anal fin base origin just behind dorsal fin
base, greater prepelvic length (70.3–72.7% SL), 25 gill rakers, and 46–47 vertebrae in D. longipes]. 相似文献
6.
Tomoaki Iseki Kouki Mizuno Taro Ohta Kouji Nakayama Masaru Tanaka 《Ichthyological Research》2010,57(3):245-253
A total of 263 adult and preadult Chinese temperate bass Lateolabrax sp. caught at 20 locations in the coastal waters of western Japan from October 1999 to September 2008 were used for age,
growth and maturity examinations. Examination of marginal increments of transverse sections of otoliths showed that rings
(opaque zones) were formed once a year from spring to summer. According to the number of rings and the sampling month, ages
were assigned to individuals. For males, we obtained the following von Bertalanffy growth equation: L(t) = 618{1 − e−0.420 (t + 0.273)}. Females attain sizes over 600 mm SL mainly after 5 years of age and attain sizes of 850–1,000 mm SL at 8–10 years and over
1,100 mm SL about 15 years. Based on histological examinations of gonads and seasonal changes in gonadosomatic indices, potential
spawning period was confirmed during mid-October to late January. In males, the minimum size and age at first maturity were
estimated as 380 mm SL and 2 years old, respectively, though most males reach sexual maturity at 3–4 years old. Furthermore,
female specimens at the mature or developing stages were over 470 mm SL and 4 years old. 相似文献
7.
Early life stages of Artedidraco skottsbergi and A. shackletoni were collected off Adélie Land. The morphology and pigmentation pattern of nine larvae and juveniles of A. skottsbergi between 17.2 and 21.4 mm in standard length (SL), and of two juveniles of A. shackletoni measuring 25.1 mm SL were described. A. skottsbergi was characterized by a heavily pigmented body, except for the caudal peduncle, with distinctively dense pigmentation on the
ventrolateral half of the body and caudal section (17.2–17.9 mm SL). Furthermore, they had no pigmentation on the pectoral
fin base until they attained 21.4 mm SL. Juvenile A. shackletoni had a heavily pigmented body except for the ventral side of the abdomen and the anal fin base. The proximal part of the dorsal
fin and most of the anal fin were covered with melanophores. Although knowledge of larval and juvenile Artedidraco species is limited, the distribution of melanophores on the fins, pectoral fin base and caudal peduncle at each developmental
stage may be useful for species identification. 相似文献
8.
Makoto Okamoto 《Ichthyological Research》2011,58(2):101-108
A new epigonid fish, Epigonus mayeri, is described on the basis of two specimens (109.7–113.8 mm in standard length: SL) from off Angola, and Epigonus heracleus Parin and Abramov 1986 is redescribed on the basis of 12 additional specimens with type specimens from off eastern New Zealand.
These species belong to a subgroup of Epigonus, known as the “Epigonus robustus group,” which have a pungent opercular spine and VII-I, 9 dorsal-fin rays. The new species differs from other species of
the group by having a sharp-pointed mustache-like process, presence of a rib on the last abdominal vertebra, vertebrae 10 + 15,
tongue toothless, pyloric caeca 5, pectoral fin reaching to vertical line from anus (length 22.2–23.6% SL), orbital diameter
16.4–17.0% SL, head length 37.8–38.0% SL, and lower jaw length 16.7–17.0% SL. 相似文献
9.
Juvenile development ofSuggrundus meerdervoortii was described, based on twelve specimens (12.9–43.8 mm SL) collected from off Yamagata Prefecture, Japan Sea. Two exterior
openings in the lateral line scales were completed at ca. 35 mm SL, with the interopercular flap and iris lappet being visible
at ca. 44 mm SL, these all being useful taxonomic characters. In juveniles and additional young and adult specimens (ca. 70–191
mm SL), the proportions of head length, snout length, orbital diameter, caudal peduncle depth and caudal fin length decreased
with growth; interorbital width decreased rapidly until ca. 70 mm SL, but more or less stabilised thereafter (70–191 mm SL). 相似文献
10.
Life history parameters associated with reproductive biology, age, and growth of the convict cichlid (also known as the zebra
cichlid) Amatitlania nigrofasciata, which was introduced into the Haebaru Reservoir on Okinawa-jima Island, were estimated using 437 specimens that ranged from
13.7 to 82.9 mm standard length (SL). Lengths of females at first maturity (SL) and 50% maturity (L
50) were estimated to be 32.2 and 37.3 mm SL, respectively. The spawning period continued throughout the year, with a peak spawning
cycle from March to May 2006–2007. Observations of postovulatory follicles and tertiary yolk stage oocytes indicate that convict
cichlids spawn multiple times within a year. Female cichlids that hatched during the peak spawning seasons matured after October
of the same year. Batch fecundity of females (32.2–61.2 mm SL) ranged from 65 to 345 (mean ± SD = 155 ± 63). Opaque zones
along the outer margins of otoliths formed annually. The maximum age of male and female cichlids was 3 years. The von Bertalanffy
growth formulae (VBGF) were expressed as Lt = 57.4( 1 - e - 0.78( t + 0.91 ) ) {{\hbox{L}}_{\rm{t}}}{ = 57}{.4}\left( {1 - {e^{ - 0.78\left( {t + 0.91} \right)}}} \right) for females and Lt = 69.5( 1 - e - 1.07( t + 0.24 ) ) {{\hbox{L}}_{\rm{t}}}{ = 69}{.5}\left( {1 - {e^{ - 1.07\left( {t + 0.24} \right)}}} \right) for males. Males grew larger than females beginning from the first year. Certain life history characteristics, such as year-round
spawning and early maturation, probably contributed to the successful establishment of the convict cichlid, and this species
in particular is thought to adapt and become established quickly upon introduction to freshwater systems on Okinawa-jima Island. 相似文献
11.
Yusuke Hibino Seishi Kimura Kazuo Hoshino Kiyotaka Hatooka John E. McCosker 《Ichthyological Research》2012,59(2):179-188
The myrophine ophichthid fishes (worm eels) Muraenichthys aoki Jordan and Snyder 1901 and Muraenichthys gymnotus Bleeker 1857 are redescribed as valid species of Scolecenchelys based on the types and non-type specimens collected from the Indo-Pacific. Because both species are similar to each other
in having acute snouts, the posterior margin of the eye before the rictus, and their dorsal-fin origins located slightly posterior
to a vertical line through the anus, Scolecenchelys aoki has usually been regarded as a junior synonym of Scolecenchelys gymnota. However, S. aoki is clearly distinguishable from S. gymnota by having a median groove on the ventral side of snout (absent in S. gymnota), uniserial maxillary teeth in smaller specimens (<200 mm TL; vs. biserial), three infraorbital sensory pores at postorbital
area (vs. two), and more numerous vertebrae (56–65 in predorsal vs. 51–57; 53–58 in preanal vs. 47–52). Scolecenchelys aoki is restricted to Japanese waters and regarded as a senior synonym of Muraenichthys borealis Machida and Shiogaki 1990. Scolecenchelys gymnota is widely distributed in the Indo-Pacific, from South Africa and the Red Sea to Samoa, north to Okinawa, Japan. Sphagebranchus huysmani Weber 1913 and Muraenichthys fowleri Schultz 1943 are synonymized under S. gymnota. 相似文献
12.
The reduction potential of a cell is related to its fate. Proliferating cells are more reduced than those that are differentiating, whereas apoptotic cells are generally the most oxidized. Glutathione is considered the most important cellular redox buffer and the average reduction potential (Eh) of a cell or organism can be calculated from the concentrations of glutathione (GSH) and glutathione disulfide (GSSG). In this study, triplicate groups of cod larvae at various stages of development (3 to 63 days post-hatch; dph) were sampled for analyses of GSSG/2GSH concentrations, together with activities of antioxidant enzymes and expression of genes encoding proteins involved in redox metabolism. The concentration of total GSH (GSH+GSSG) increased from 610±100 to 1260±150 μmol/kg between 7 and 14 dph and was then constant until 49 dph, after which it decreased to 810±100 μmol/kg by 63 dph. The 14- to 49-dph period, when total GSH concentrations were stable, coincides with the proposed period of metamorphosis in cod larvae. The concentration of GSSG comprised approximately 1% of the total GSH concentration and was stable throughout the sampling series. This resulted in a decreasing Eh from −239±1 to −262±7 mV between 7 and 14 dph, after which it remained constant until 63 dph. The changes in GSH and Eh were accompanied by changes in the expression of several genes involved in redox balance and signaling, as well as changes in activities of antioxidant enzymes, with the most dynamic responses occurring in the early phase of cod larval development. It is hypothesized that metamorphosis in cod larvae starts with the onset of mosaic hyperplasia in the skeletal muscle at approximately 20 dph (6.8 mm standard length (SL)) and ends with differentiation of the stomach and disappearance of the larval finfold at 40 to 50 dph (10–15 mm SL). Thus, metamorphosis in cod larvae seems to coincide with high and stable total concentrations of GSH. 相似文献
13.
Short-term variability in vertical distribution and feeding of Atlantic mackerel (Scomber scombrus L.) larvae was investigated while tracking a larval patch over a 48-h period. The patch was repeatedly sampled and a total
of 12,462 mackerel larvae were caught within the upper 100 m of the water column. Physical parameters were monitored at the
same time. Larval length distribution showed a mode in the 3.0 mm standard length (SL) class (mean abundance of 3.0 mm larvae
=75.34 per 100 m3, s=34.37). Highest densities occurred at 20–40 m depth. Larvae <5.0 mm SL were highly aggregated above the thermocline, while
larvae ≥5.0 mm SL were more dispersed and tended to migrate below the thermocline. Gut contents of 1,177 mackerel larvae (2.9–9.7 mm
SL) were analyzed. Feeding incidence, mean number (numerical intensity) and mean dry weight (weight-based intensity) of prey
items per larval gut were significantly dependent on larval size. However, while weight-based feeding intensities continued
to increase with larval length, numerical intensity peaked at 4–4.9 mm SL, indicating a shift in the larval diet. While first-feeding
larvae relied most heavily on copepod nauplii and eggs, larvae ≥5.0 mm SL initiated piscivorous feeding. All identifiable
fish larvae were Atlantic mackerel. Thus, the piscivory was cannibalism. Larval feeding incidence and numerical feeding intensities
peaked during daytime and were reduced at night. Daily ration estimates for first-feeding mackerel larvae <4.0 mm SL were
extremely low
= 1.43% body dry weight, but increased dramatically at 5.0 mm SL, i.e., at the onset of cannibalism, reaching >50% body dry
weight in larva ≥8.0 mm SL.
Received in revised form: 31 October 2000
Electronic Publication 相似文献
14.
Age, growth, and reproductive biology of the Waigieu seaperch Psammoperca waigiensis were studied using 291 specimens obtained around Okinawa Island, Japan. Otolith opaque zones that formed every year correlated
with spawning activity and were thought to be annual rings. Growth of this species was rapid during the first 2 years, reaching
186.2–270.3 mm in standard length (SL). Females (196.6–334.0 mm SL) were larger than males (186.2–288.6 mm SL), caused by
differential growth between sexes, which started before 2 years of age. Most of the specimens were 1–11 years old and accounted
for 96% in total. Spawning season was estimated to be from April to October by gonadosomatic index (GSI) and histological
observation. The smallest mature female and male were 217.0 mm SL (2 years) and 206.0 mm SL (2 years), respectively. After
recruitment in rocky areas up to about 200.0 mm SL and 2 years of age, Psammoperca waigiensis were then found to soon mature. 相似文献
15.
Molnar SJ Chapados JT Satheeskumar S Wight CP Bancroft B Orr W Luckert DE Kibite S 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(6):1115-1125
Seven pairs of oat near-isogenic lines (NILs) (Kibite in Crop Sci 41:277–278, 2001) contrasting for the Dw6 dwarfing gene were used to test for correlation between tall/dwarf phenotype and polymorphic genotype using restriction fragment
length polymorphism (RFLP) and other molecular markers selected from the Kanota × Ogle (K×O) (Wight et al. in Genome 46:28–47,
2003) and Terra × Marion (De Koeyer et al. in Theor Appl Genet 108:1285–1298, 2004) recombination maps. This strategy located the Dw6/dw6 locus to a small chromosomal region on K×O linkage group (LG) KO33, near or at a putative RFLP locus aco245z. Aco245z and
other tightly linked flanking markers have potential for use in marker-assisted selection (MAS), and PCR-based markers were
developed from several of these. RFLP genotyping of the Dw6 NILs indicated that 13 of the 14 individual lines were homogeneously maternal or paternal for a large genomic region near
Dw6/dw6, an unexpected result for NILs. The cDNA clone aco245 codes for a vacuolar proton ATPase subunit H, a potential candidate
gene for Dw6. Vacuolar proton ATPase enzymes have a central role in plant growth and development and a mutation in subunit C is responsible
for the det3 dwarfing mutation in Arabidopsis thaliana (Schumacher et al. in Genes Dev 13:3259–3270, 1999). Aco245 affords the potential of designing highly precise diagnostic markers for MAS for Dw6. The Dw6 NILs have potential utility to investigate the role of vacuolar proton ATPases in growth and development in plants. 相似文献
16.
Wim J. Vredenberg 《Photosynthesis research》2009,102(1):99-101
Quantitative data on laser flash-induced variable fluorescence in the 100 ns to 1 ms time range (Belyaeva et al. in Photosynth
Res 98:105–119, 2008) confirming those of others (Steffen et al. in Biochemistry 40:173–180, 2001, Biochemistry 44:3123–3132, 2005; Belyaeva et al. in Biophysics 51(6):976–990, 2006), need a substantial correction with respect to magnitude of the normalized variable fluorescence associated with single
turnover-induced charge separation in RCs of PS II. Their data are conclusive with the involvement of donor side quenching,
the release of which occurs with a rate constant in the range of tens of ms−1, and presumed to be associated with reduction of
Y\textz + Y_{\text{z}}^{ + } by the OEC. 相似文献
17.
Hannibal T. Musarurwa Johannes van Staden Nokwanda P. Makunga 《Plant Growth Regulation》2010,61(3):287-295
The aromatic medicinal plant Salvia stenophylla contains α-bisabolol, making this plant an important contributor to the aromatherapy and cosmetic industries in South Africa.
Due to its commercial importance, the cultivation of this plant using an in vitro system was considered. Firstly, seedlings
were raised in vitro after breaking dormancy with light, smoke-water or chemical scarification treatments. Germination improved
when seeds were smoke-treated or soaked in 70% (v/v) H2SO4. Vigorous plantlet regeneration was achieved when seedling explants were cultured on Murashige and Skoog (1962) medium with 5.7 μM IAA and 8.9 μM BA. The potential regeneration capacity for this protocol was estimated and over 1,000
plantlets can be produced from a single shoot (6.67 cm with 4–6 nodes) over a period of 3 months. Plants rooted easily regardless
of their growth medium. This was followed by their successful rapid establishment and normal growth out of culture (75%).
Finally, the volatile compounds in in vitro plants were compared to ex vitro plants via headspace solid phase microextraction
linked to gas chromatography–mass spectrometry. The chemical complexity of microplants was similar to wild plants with in
vitro plants continuing to produce α-bisabolol (21%) at high levels. 相似文献
18.
Yaser Hassan Dewir Nisha Singh Shakira Shaik Ashley Nicholas 《In vitro cellular & developmental biology. Plant》2010,46(1):41-46
The present study reports a simple protocol for indirect shoot organogenesis and plant regeneration of Sutherlandia using rachis and stem segments. Different concentrations (0.0–68.08 μmol l−1) of thidiazuron (TDZ) were used for callus induction and shoot organogenesis. The highest percentage of callus formation
(97.5%) and the highest percentage of explants forming shoots (88.8%) were obtained from rachis explants cultured onto Murashige
and Skoog (MS) medium (Murashige and Skoog, Physiol. Plant. 15:473–495, 1962) supplemented with 45.41 μmol l−1 TDZ. Scanning electron microscopy demonstrated the early development of adventitious shoots derived from callus cultures.
Shoot clusters were further developed and grown in MS hormone-free medium. The presence of l-canavanine was determined by thin-layer chromatography and confirmed after column fractionation using silica gel and nuclear
magnetic resonance spectroscopy. Individual shoots were rooted on different concentrations and combinations of MS salt strength
and IBA. Half-strength MS salt medium supplemented with 24.6 μmol l−1 IBA was optimal for root induction in which 78% of shoots were rooted. The in vitro plants were successfully acclimatized in a growth chamber with a 90% survival rate. 相似文献
19.
Naoki Yagishita Yoshiaki Kai Atsushi Yamasaki Tetsuji Nakabo 《Ichthyological Research》2007,54(2):198-206
Morphological and genetic differences between red and yellow morphotypes of Sebastes owstoni were investigated, utilizing 277 males [84.0–194.3 mm in standard length (SL)] and 542 females (92.3–251.5 mm SL) from the
Sea of Japan. All males smaller than 120 mm SL were characterized by red body color. The frequency of specimens with yellow
body color thereafter increased gradually with SL, all specimens larger than 170 mm SL being yellow. The specimens with yellow
body color were observed throughout the year. All females smaller than 170 mm SL were characterized by red body color, the
frequency of specimens with yellow body color tending to slightly increase with SL. However, most females had red body color,
except for 16 specimens (177.7–241.5 mm SL) that were yellow, growth-related color change from red to yellow being uncommon.
Morphological analysis of 49 males (107.6–193.3 mm SL) and 68 females (108.7–241.5 mm SL) showed the head length, orbit diameter,
lower jaw length, and predorsal length to be relatively greater, but the distance between the pelvic and anal fins less, in
males. A discriminant analysis using Mahalanobis distances resulted in 100% correct assignment of specimens to sex, regardless
of SL and body color. In addition, no genetic differences were apparent between red and yellow individuals in mitochondrial
DNA sequence analyses from the threonine tRNA to the first half of the control region (498 bp). Accordingly, the differences
in body color, maximum size, and the five morphometric characters listed above were considered to represent sexual dimorphism.
That evidenced by body color was considered to appear after that shown by morphometric characters, some exceptions in the
former occurring in females. This is the first report of permanent sexual dimorphism in body color in Sebastes. 相似文献
20.
Makoto Okamoto Keiichi Takeda Hiroya Sugisaki Takashi Asahida 《Ichthyological Research》2007,54(1):61-67
The early life stages of Lestidiops sphyraenopsis (Paralepididae) are described on the basis of 14 specimens [7.8 mm in notochord length (NL)–88.6 mm in standard length (SL)]
collected from the western North Pacific, and the holotype of Stemonosudis molesta is reexamined. Larval L. sphyraenopsis occurred in the Kuroshio waters, and juveniles were taken in the Kuroshio–Oyashio transition waters. Diagnostic characters
of larval and juvenile L. sphyraenopsis are 96–101 myomeres; 27–31 anal fin rays; 4–9 peritoneal pigment sections in larvae (7.8 mm NL–27.3 mm SL); dorsal and anal
pigment patches present; and anus located anterior to a vertical through dorsal fin origin. Stemonosudis molesta, known only from the holotype from the South Pacific, is similar to immature specimens of L. sphyraenopsis, but can be clearly distinguished from the latter by having higher vertebral counts (105 vs. 96–101) and by morphometric
and pigment differences. Consequently, S. molesta is a valid species, and the distribution of L. sphyraenopsis is restricted to the North Pacific. 相似文献