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1.
I. D. Tuck A. C. Taylor R. J. A. Atkinson M. E. Gramitto C. Smith 《Marine Biology》1997,129(3):505-511
Changes in the biochemical composition of the ovary of Nephrops norvegicus (L.) were examined throughout maturation at stations with fast and slow growing individuals in Scottish waters and in the
Mediterranean. Ovary index (ovary wt:total body wt) increased significantly with maturation. Lipid, protein and water content
of the ovary increased with maturation, while carbohydrate content decreased. Similar changes were also identified in the
hepatopancreas. Significant spatial differences in ovary and hepatopancreas composition were identified, which may be related
to whole-body growth rate. The ovary maturation scale commonly used for N. norvegicus was shown to reflect biochemically distinct stages in ovary development.
Received: 7 February 1997 / Accepted: 25 February 1997 相似文献
2.
We determined the temporal evolution of amylase, cellulase, laminarinase and protease in the digestive gland and crystalline
style of cockles Cerastoderma edule held over 9 to 12 d in the presence and absence of food. Cockles were fed a constant diet of 1.5 mm3 l−1 of Tetraselmis suecica for 9 to 12 d and were then starved for 6 to 8 d in late summer (September 1992) and in winter (January 1993). Feeding increased
the dry weight and total cellulase, laminarinase and protease activities of the digestive gland irrespective of season, whereas
amylase activity remained unchanged. In winter (i.e. when cockles are metabolically weak) the response was faster and stronger,
especially for protease. An additional experiment in September starved cockles for 20 d before resuming feeding. In agreement
with the seasonal differences, the presence of food after prolonged starvation induced a rapid and marked increase in protease
in the digestive gland of the cockles. In winter, the possible effects of the biochemical composition of food on their enzymatic
response were tested by feeding two groups of cockles with the same ration of T. suecica but harvested at different growth phases. A compensatory induction of cellulases occurred in cockles fed on T. suecica with a lower carbohydrate content. In the crystalline style, the protein level and carbohydrase fell during the first day
of feeding and increased during the first day of subsequent starvation. These results indicate that the release of enzymes
from the style prevails over the incorporation of enzymes during the early stages of feeding, whereas the opposite occurs
during starvation.
Received: 15 February 1998 / Accepted: 22 February 1999 相似文献
3.
Using the number of segments of pleopod rami as a marker of instar number, the population structure (instar composition)
of the mesopelagic gammarid amphipod Cyphocaris challengeri was investigated by monthly samplings from May 1997 to April 1999 at a station off southwest Hokkaido, Japan. Laboratory-rearing
experiments were also conducted to establish the relationship between the number of segments of pleopod rami and instar number,
and to estimate the growth pattern of this gammarid based on the intermolt period and molt-increment data. Stratified sampling
in the field (0 to 200 and 200 to 400 m depth strata) showed this species occurred mainly at 200 to 400 m depth during the
day. Instar analysis indicated that C. challengeri has 12 instars in females and 11 instars in males. Based on observations of secondary sexual characters, Instars 1 to 6 were
designated juveniles (Instars 1 to 3 occurred in the marsupia of gravid females); in males, 7 to 9 were immature and 10 and
11 were mature, while in females 7 and 8 were immature and 9 to 12 were mature. Off southwest Hokkaido, Instar 4 (just released
from a female's marsupium) was found throughout the year, with a peak abundance occurring in April to July of each year. A
sequential development of Instar 4 to 9 (youngest adult instar) through the year was observed. Generation length (i.e. the
time required to grow from Instar 4 to 10) was estimated from a laboratory-obtained growth curve to be 216 to 584 d at the
in situ temperature range (2 to 5 °C), which is consistent with observations on field populations. Specimens older than Instar
9 were rare in the field and could not be used in laboratory-rearing experiments, so longevity could not be estimated. Eggs
were oval and measured 0.6 mm (large diameter). Brood size ranged from 20 to 65. Comparing the present results with those
of epipelagic hyperiid amphipods, the nearly identical growth rates together with the production of fewer but larger eggs
seen in C. challengeri appear to reflect to the typical life mode of deep-living pelagic crustaceans.
Received: 14 February 2000 / Accepted: 6 July 2000 相似文献
4.
Understanding physiological and environmental variables that initiate sexual maturity would provide fundamental information
on life history dynamics. The aim of this study was to test the usefulness of the common circumnuclear ring (CNR), an oocytic
structure similar to the Balbiani body, which appears just prior to oocyte development as a predictor of first maturation
in Atlantic herring (Clupea harengus). The relative roles of physiology (e.g. fat) and photoperiod as triggers of maturation were also investigated. Samples were
collected in May 2008 (72°26′–73°84′N/11°26′–18°40′E) and February 2009 (56°12′–59°45′N/00°25′–03°06′W). These data suggested
that thresholds in body size may influence the decision to mature. We also found that short days (winter solstice) may be
the photoperiod trigger for a first-decision window for both Norwegian spring-spawning (NSS) and North Sea autumn-spawning
(NSAS) herring. The second-decision window for NSAS herring maturation appears to be triggered by longer days (spring equinox),
while a decreasing rate of day lengthening may trigger NSS herring maturation. So, photoperiodic cycle is a key determinate
of the timing of maturation in Atlantic herring. 相似文献
5.
The endogenous rhythm of oxygen consumption in juvenile spotted sea bass (Lateolabrax sp.) was measured to test the effects of sudden changes in salinity on the metabolic activity. Mean oxygen consumption rates
of this euryhaline fish decreased by 13.5 to 16.0% and 25.3 to 36.4% when they were transferred from 31.5 to 15‰ seawater
and to fresh water (0‰), respectively. The maximum rate of oxygen consumption was observed between 18:00 and 19:00 hrs local
time, 1 to 2 h before sunset, even though they were kept in constant darkness. The peaks of oxygen consumption occurred in
23.2- and 23.3-h intervals, which correspond with a circadian rhythm, as revealed by maximum entropy spectral analysis. A
markedly weakened rhythm in oxygen consumption occurred from 8 to 10 d after onset of the experiments. This study indicates
that spotted sea bass can withstand sudden drops in salinity from 31.5‰ to fresh water, and yet maintain a regular though
somewhat dampened endogenous rhythm of oxygen consumption.
Received: 16 June 1997 / Accepted: 3 February 1998 相似文献
6.
We used an immunofluorescence technique to investigate the effects of varying light regimes on ribulose 1,5-bisphosphate
carboxylase/oxygenase (Rubisco) in individual cells of the chlorophyte Dunaliella tertiolecta Butcher. These studies were carried out between September 1995 and February 1996. The population was heterogeneous with respect
to Rubisco localization in the pyrenoid, i.e. in some cells Rubisco staining was highly concentrated in the pyrenoid while
in others it was evenly distributed throughout the chloroplast stroma. When light intensity was varied sevenfold, the fraction
of the cell population that displayed distinct Rubisco staining in the pyrenoid (PR-index) was correlated with light intensity,
although the average Rubisco abundance per cell or per total cellular protein appeared fairly constant. In darkness, or when
treated with 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU), the PR-index decreased markedly during the first 4 and 3 h,
respectively, and then remained at low levels, while the cell division cycle progression remained unaffected. We conclude
that D. tertiolecta probably possesses an adaptive mechanism, i.e. the redistribution of Rubisco between the pyrenoid (probably the active site
of Rubisco activation and CO2 fixation) and the stroma (probably a reservoir of deactivated Rubisco that is readily available for transport to the pyrenoid
and activation), to respond to variations in irradiance or photosynthetic inhibition. Our results also suggest that this mechanism
is insensitive to slight variations in growth irradiance and to seasonal changes in photoperiod and temperature.
Received: 19 August 1996 / Accepted: 12 September 1996 相似文献
7.
Incorporation of 3H-labelled glucose and 3H-labelled N-acetylglucosamine (NAGA) — both precursors to chitin —into the cuticle of Rhithropanopeus harrisii (Gould) larvae (Crustacea: Brachyura) has been examined at different stages of the moult cycle in control larvae as well as in larvae treated with the insect growth regulator diflubenzuron (Dimilin®). As far as the control larvae were concerned, the incorporation of both precursors was high at the postmoult stage when endocuticle was secreted. NAGA appeared to be a more specific precursor of cuticular material than glucose during the premoult stage when exocuticle was produced. Incorporation of both precursors was low immediately before ecdysis and during the intermoult stage when secretion of the cuticle is complete. The results show that incorporation of glucose into chitin was greatly inhibited by the pollutant during the postmoult stage when endocuticle is produced, while incorporation of NAGA was reduced to a lesser extent at this stage. Diflubenzuron treatment markedly affected the incorporation of both NAGA and glucose in the premoult stage during secretion of exocuticle. 相似文献
8.
Most pandalid shrimps show protandric hermaphroditism, and male sexual differentiation is considered to be controlled by the androgenic gland. In the present study, we examined the histology of gonadal development during the male phase and sex change and the involvement of the androgenic gland in regulating male reproduction in laboratory-maintained Pandalus hypsinotus. Juvenile shrimps developed testicular tissues in the peripheral part of gonads during the age of 16–31 months and produced spermatozoa between 34 and 36 months. After reaching sexual maturity, male shrimps exhibited seasonal testicular development: active production of spermatozoa (February–May), disappearance of spermatozoa (spent, April–June), increase of spermatocytes (May–November), appearance of spermatids and spermatozoa in the gonads (November–February). The androgenic gland cells became larger and the rough endoplasmic reticulum in the cytoplasm developed at male sexual maturity. The cell structure shows that the androgenic gland hormone is a peptide. Furthermore, bilateral eyestalk ablation on immature male shrimps induced hypertrophy of the androgenic gland and acceleration of male sexual maturation. These results indicate the involvement of androgenic gland hormone and some eyestalk factor in regulating male sexual maturation. Over a 1-year laboratory-rearing period, some male shrimps (16.7%) changed sex. In transitional shrimps, testicular tissues in the gonads and androgenic glands degenerated; on the other hand, oocytes started yolk protein accumulation and hemolymph vitellogenin levels became high. These results suggest that androgenic gland degeneration is a trigger for sex change and that the vitellogenin level is a useful marker for sex change. 相似文献
9.
Fluoride in Antarctic marine crustaceans 总被引:2,自引:0,他引:2
The concentration of fluoride in the body parts of a range of Antarctic crustaceans from a variety of habits was examined
with the aim of determining whether fluoride concentration is related to lifestyle or phylogenetic grouping. Euphausiids had
the highest overall fluoride concentrations of a range of Antarctic marine crustaceans examined; levels of up to 5477 μg g−1 were found in the exoskeleton of Euphausia crystallorophias. Copepods had the lowest fluoride levels (0.87 μg g−1 whole-body); some amphipods and mysids also exhibited relatively high fluoride levels. There was no apparent relationship
between the lifestyle of the crustaceans and their fluoride level; benthic and pelagic species exhibited both high and low
fluoride levels. Fluoride was concentrated in the exoskeleton, but not evenly distributed through it; the exoskeleton of the
head, carapace and abdomen contained the highest concentrations of fluoride, followed by the feeding basket and pleopods,
and the eyes. The mouthparts of E.␣superba contained almost 13 000 μg F g−1 dry wt. Antarctic krill tail muscle had low levels of fluoride. After long-term (1 to 5 yr) storage in formalin, fluoride
was almost completely lost from whole euphausiids.
Received: 1 April 1998 / Accepted: 29 July 1998 相似文献
10.
K. Parvathy 《Marine Biology》1971,10(1):82-86
InEmerita asiatica, the quantitative fluctuations in the glycogen content of the hepatopancreas were markedly related to the moult cycle. The glycogen content of the hepatopancreas was maximum during premoult stages. It has been suggested that reserve glycogen, in addition to meeting general metabolic needs, may be especially involved in the genesis of the sugar precursors of chitin. The marked fall in the hepatopancreas glycogen values following moulting is probably due to its utilization in chitin synthesis during and immediately following moulting. InE. asiatica, the storage of glycogen was found to be meagre in muscles, and muscle glycogen had no bearing on chitin synthesis during moulting. InLigia exotica, glycogen is stored to a lesser extent than inE. asiatica, and was found in connective tissue and muscles. Significant fluctuations were noted in glycogen values correlated with the phases in the moult cycle when chitin synthesis took place. InL. exotica, the hepatopancreas does not serve as a storage depot for glycogen related to chitin synthesis. 相似文献
11.
X. de Montaudouin 《Marine Biology》1997,128(4):639-648
Juvenile bivalves may be dispersed by entering a bysso-pelagic phase where they drift through the water mass aided by a long
thread. The ability to resuspend and control the specific weight in two bivalve species, the cockle Cerastoderma edule (L.) and the Japanese clam Ruditapes philippinarum (Adams and Reeves), was documented with juveniles through flume and still-water experiments. Cockle juveniles initially placed
on an unsuitable substratum were exposed to two shear velocities (u
*). At the end of the experiment, 42 (±15)% (for u
*=0.51 cm s−1) and 79 (±9)% (for u
*=0.99 cm s−1) of individuals were retrieved from the sand area which represents only 8% of the total flume surface. Most juveniles (70.5%)
with shell lengths <2.5 mm migrated from the unsuitable Plexiglas substratum to the sand array by resuspension in the water
column. The percentage was lower (21.5%) for larger individuals. The same experimental design was applied to clams, which
immediately adhered to the Plexiglas substratum and remained attach to it. Sinking rates of live and dead specimens of both
species were measured in a 1 m long transparent PVC tube. Cockle fall velocities showed severe deceleration, probably due
to byssus secretion (up to 15-fold slower than dead cockles), sometimes interrupted by brutal acceleration probably due to
byssal rupture. Cockles were able to reduce their sinking rate for shell lengths up to 4.25 mm. By contrast, clam sinking
rates were constant, and similar to dead clam sinking rates. Specific weights of all experimental juveniles were calculated
in relation to their lengths, and their passive motion into the boundary layer was theoretically assessed with Shields curve.
In short, C. edule and R. philippinarum can both exhibit dense populations in the field with a good capacity to colonize, although juveniles display different abilities
to resuspend in the water column.
Received: 27 January 1997 / Accepted: 13 February 1997 相似文献
12.
The Norway lobster Nephrops norvegicus (L.) inhabits burrows in muddy clay sediments (e.g. on the Swedish west coast), where an autumnal oxygen deficiency in the
bottom water can occur. Our experiments investigated whether the irrigation of the burrows would reflect a behavioural adaptation
to hypoxia, and whether any gender differences of such behaviour exist. Irrigation is performed by the pleopods which may
compensate for a decreasing oxygen tension. Pleopod activity (total number of strokes per sampling time), associated with
oxygen concentration and gender, was studied in N. norvegicus kept in artificial burrows resembling their natural habitat. Male and female lobsters were separately exposed to either normoxia
(70% oxygen saturation) or hypoxia (30% oxygen saturation). A sexual difference in behaviour was found, where females irrigated
the burrow less than males during normoxia. Females showed a significant increase of pleopod activity in hypoxia compared
with normoxic conditions, which was not displayed by the males probably due to the degree of individual variation found. However,
when only males were studied during progressive hypoxia (from 60 to 5% oxygen saturation), following any changes of irrigational
behaviour, a significant increase of accumulated pleopod activity occurred. A major increase of pleopod activity appeared
between 60 and 50% oxygen saturation, below which the activity remained high until a critical point (<10% saturation, 11 °C,
33 psu) where irrigation dropped to a level close to that of normoxic values. Activity sessions during hypoxia were longer
and had a higher stroke rate than during normoxia.
Received: 22 October 1997 / Accepted: 26 February 1998 相似文献
13.
To elucidate the effects of temperature and algal cell concentration on pumping of water in the ascidian Ciona intestinalis a number of different experiments were performed. Beat frequency of the lateral cilia in the openings of the branchial sac
was measured in intact specimens using a microprojection objective and a monochrome CCD video camera. At constant low algal
cell concentration, beat frequencies increased linearly with temperature from 4.0 Hz (±0.5) at 7.4 °C to 13.6 Hz (±1.6) at
20.1 °C. At a constant temperature of 15 °C, beat frequency decreased with increasing algal cell concentration from approximately
3000 to >10 000 Rhodomonas sp. cells ml−1. The decrease was observed both in experiments where the ascidians had been acclimated to a fixed algal cell concentration
and in experiments with changing concentrations. Effect of algal cell concentration on squirting/siphon closure and flow velocity
in the exhalent siphon was measured using a thermistor. At low algal cell concentrations, flow velocity in the exhalent siphon
was stable, apart from a few short squirts. At very high algal cell concentrations, the flow velocity was reduced and much
less stable, with prolonged squirting. The effect of gut content on filtration was studied in experiments with specimens acclimated
to high algal cell concentrations. Results showed a close relation between gut clearance and filtration rate. From the experimental
results and a qualitative analysis of the Ciona-pump it was concluded that the ciliary beat frequency is proportional to the water flow through the sea squirt and that changes
in pumping caused by temperature or algal cell concentration are under nervous control or governed by enzyme kinetics, rather
than being a result of physico-mechanical properties, i.e. pump efficiency versus flow resistance, of the ascidian pump.
Received: 6 October 1997 / Accepted: 8 October 1998 相似文献
14.
Juvenile squids were grown in individual 2.6-l floating enclosures and were fed either a high- or a low-ration diet of fish
and the crustacean Acetes. Squids were maintained for a maximum of 44 days in two experiments. The high-ration individuals reached a significantly
larger size in both experiments (27, 25.5 mm mean mantle length, ML) compared to their low-ration siblings (19 mm mean ML)
in both experiments. The statolith increment widths prior to the start of the experiment were significantly wider (between
3 and 4 μm) compared to the increment widths after the start of the experiment (between 2 and 3 μm) both for the low- and
the high-ration squids. High-ration squids also had significantly wider increments and larger statoliths than their low-ration
siblings. Even though we detected consistent trends in daily statolith increment widths for the different feeding regimes,
we could not detect variation in increment widths at a daily level of resolution (i.e. as a result of differences in day-to-day
food intake at an individual level). This was probably due to the relatively consistent diet experienced by each individual.
These experiments revealed that ration level influences squid growth rate, statolith size and daily statolith increment width.
Received: 30 March 2000 / Accepted: 30 October 2000 相似文献
15.
Early development of the Antarctic sea urchin Sterechinus neumayeri was examined under two differ-ent culture regimes: one to simulate development near-bottom (“demersal development”) and the
other to simulate the development of embryos in the water column (“pelagic development”). When embryos of both treatments
reached the hatching blastula stage at 5 d post-fertilization (−1.5 °C), the blastulae that had undergone demersal development
evidenced significant differences (by ANOVA or suitable non-parametric comparison) in the following: a thicker blastoderm
layer (12%, P < 0.001), higher ash-free dry weights (19%, P < 0.01), lower mass-specific respiration rates (50%, P < 0.001), higher incorporation rates of 35S-methionine into protein (23%, P < 0.003), and a differential pattern of protein synthesis. When embryos developed demersally, they remained in the jelly-coat
material released with the eggs at spawning. Quantitative isolation of this jelly-coat material in S. neumayeri demonstrated that it contained a significant amount of organic matter, 115 ng ash-free dry mass per egg, equivalent to 17%
of the egg's initial organic mass. Uptake of external nutrients during embryogenesis may be a significant component of the
physiological energetics of this polar invertebrate by allowing the utilization of jelly-coat material released by a female
during spawning.
Received: 21 April 1999 / Accepted: 5 June 2000 相似文献
16.
Klaus Peschke Peter Friedrich Uwe Kaiser Stephan Franke Wittko Francke 《Chemoecology》1999,9(2):47-54
Summary. In the rove beetle Aleochara curtula, a male specific sternal gland is described. Isopropyl (Z9)-hexadecenoate has been identified by GC/MS of surface and sternal gland extracts as a male specific compound. Its emission
in the air was demonstrated by closed-loopstripping-analyses. In field experiments, conspecific males and females were attracted
by the odor of carrion, caged males from laboratory cultures, and by the synthetic ester. Isopropyl (Z9)-hexadecenoate or live males, combined with fresh carrion attract more beetles than a fresh carcass alone. Isopropyl hexadecanoate
as a minor compound was not attractive. The term “aggregation” pheromone and the ecological significance of attracting females
to a fresh carcass allowing early copulation and egg-deposition are discussed.
Received 20 August 1998; accepted 15 January 1999. 相似文献
17.
Although dimethylsulfoniopropionate (DMSP) has a variety of functions in marine macroalgae including that of a cryoprotectant,
an osmolyte, a way to remove excess sulfur and energy, an antioxidant, and an allelopathic precursor, the latter two functions
are believed to be the most important in Ulva lactuca L. (=U. fenestrata) in intertidal populations on the coast of Washington state, USA. The present study found significant variation in DMSP concentrations
among U. lactuca collected in May 2005 from six sites ranging from 47°54.45′N (Possession Point, Whidbey Island, WA, USA) to 48°30.55′N (Shannon
Point Beach, Anacortes, WA, USA), and also among individuals within sites, and among tissues (basal tissues near the holdfast,
middle of the blades, and tips). Concentrations ranged from 37 to 224 μmol g−1 fresh mass (FM). In several 10-day experiments between July 2001 and August 2004 with U. lactuca collected from several places on the coast of Washington, the effects of nutrient level (DIN), light intensity and wavelength,
and grazing by the herbivorous gastropod Lacuna vincta, were examined. None of these manipulations resulted in DMSP concentrations that differed significantly from controls, and
variance in DMSP concentrations within each experiment was very low. Although DMSP concentrations in U. lactuca may be affected by factors not tested in these experiments, it is also possible that the observed spatial differences reflect
constitutive genotypic or phenotypic differences among geographically separated U. lactuca populations or among cryptic Ulva species.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
18.
From September to November 1991, UV-absorbing mycosporine-like amino acids (MAAs) were monitored in a natural population of
the sea urchin Sterechinusneumayeri from a coastal area of Anvers Island (Antarctic Peninsula). MAA concentrations were determined for specific tissues (gonad,
digestive tract and body wall) from adults collected at four depths (intertidal, 8, 15 and 24 m). Four MAAs were identified:
mycosporine-glycine, shinorine, porphyra-334 and paly-thine. Concentrations of MAAs among replicate individuals varied considerably.
Ovaries had high concentrations of MAAs (84 to 1389 μg g−1 dry wt), while testes had non-detectable levels. The relative abundance of specific MAAs in ovaries appeared to be related
to the spawning cycle. Digestive-tract samples had MAA concentrations as high as 3000 μg g−1 dry wt, but the mean MAA content in intertidal individuals decreased by 70% over 3 mo during spring. The body walls of sea
urchins had very low amounts of MAAs (≤ 0.08 μg g−1 dry wt). There were significant depth differences in the␣total MAA content of the ovary ( p <0.001), ( p <0.015), digestive tract ( p <0.001), and body wall with organisms from the intertidal and 8 m depth having the highest concentrations of MAAs. Biological
dosimetry indicated that UV-B (280 to 320 nm) wavelengths penetrated 3 to 7 m below the sea ice during the study period. The
total MAA content in ovaries decreased with depth on all sample dates; however, the MAA content of the digestive tract and
body wall did not exhibit a consistent pattern of change with depth. The MAA content of tissues did not change significantly
with the temporal gradient of light exposure that was established by both ozone depletion and increasing photoperiod, except
in the digestive tract sampled from intertidal specimens. Adult urchins are probably well-protected from UV exposure by the
water column and a calcareous test; however, the results of this study suggest that, even under ice cover, depth of habitation
is a determinant of MAA content in S. neumayeri. Large daily and seasonal fluctuations in the light regime, which are characteristic of Antarctic coastal environments, apparently
do not provide reliable cues to elicit a detectable, temporal, biochemical response.
Received: 19 February 1997 / Accepted: 26 March 1997 相似文献
19.
Rates of respiration and protein synthesis were measured during embryonic and larval development of Antarctic asteroids with
different life-history modes (non-feeding and feeding larvae: Acodontaster hodgsoni, Porania antarctica, Odontaster meridionalis). Patterns of respiration for these species all show an increase during embryogenesis, with subsequent maintenance of routine
respiration (“starvation resistance”), even in the absence of food for ~4 months (O. meridionalis). Fractional rates of protein synthesis (i.e., rate per unit mass of whole-body protein content) in the Antarctic larvae
are essentially identical to those of temperate species. Larvae of O. meridionalis had an average fractional synthesis rate of 0.52% ± 0.05 h−1 at −1.0°C, which is comparable to the temperate asteroid Asterina miniata at 0.53% ± 0.14 h−1 at 15°C. For embryos of the asteroids A. hodgsoni and P. antarctica, fractional rates of protein synthesis (~0.2% h−1) also are comparable to those reported for embryos of temperate echinoderm species. While rates of synthesis are high, rates
of protein deposition are relatively low (percent of protein synthesized that is retained for growth). During a ~4 month growth
period for larvae of O. meridionalis, the average protein depositional efficiency was 5.2%. This contrasts with higher rates of depositional efficiency reported
for similar developmental stages of temperate echinoderm species. The biological significance of maintaining high rates of
macromolecular synthesis for species with low rates of cell division and low protein depositional efficiencies is intriguing
in the context of understanding the mechanistic bases of extended life spans and dispersal potential in response to changing
Antarctic environments. 相似文献
20.
Effects of food type and ration on reproductive maturation and growth of the sea urchin Strongylocentrotus droebachiensis 总被引:1,自引:0,他引:1
We investigated the effects of food quality and quantity on reproductive maturation and growth of juveniles of Strongylocentrotus droebachiensis (Müller) in a 22 month laboratory experiment in which we fed sea urchins four diets: (1) kelp (Laminaria spp.) for 6 d wk−1 and mussel (Mytilus spp.) flesh for 1 d wk−1 (KM); (2) kelp for 7 d wk−1 (high ration, KH); (3) kelp for 1 d wk−1 (low ration, KL) and (4) no food other than encrusting coralline algae (NF). At their first and second opportunity for reproduction,
all sea urchins in the KM and KH treatments, and most in the KL treatment were reproductively mature, whereas all sea urchins
in the NF treatment remained immature. Gonad index differed significantly among all fed treatments at first and second reproduction,
and was highest in the KM and lowest in the KL treatment. Gonad index was similar in both sexes at first reproduction, but
it was higher in females than in males at second reproduction. Diet had little or no effect on the relative abundance of spermatocytes,
spermatozoa, or nutritive phagocytes in testes at first and second reproduction. In ovaries, nutritive phagocytes were significantly
more abundant in females in the KM and KH treatments than in the KL treatment at first reproduction, and significantly more
abundant in unfed (NF) than fed (KM, KH, KL) females at second reproduction. Mean oocyte size was similar in all fed females
at first reproduction, but significantly larger in fed than unfed females at second reproduction. Mean ovum size was similar
in all fed females in both reproductive periods. Increase in test diameter was greatest in the KM treatment and smallest in
the KL treatment; sea urchins in the NF treatment decreased slightly in size. Survival was 95 to 100% in all fed sea urchins
but significantly lower in unfed ones. The feeding rate on kelp was significantly greater in the KL than the KM and KH treatments.
In the KM treatment, the feeding rate on kelp increased significantly over a 6 d period after mussel flesh was provided. Our
results demonstrate that a diet of high food quality and quantity accelerates reproductive maturation and growth rate, and
enhances gonad production and survival in juvenile and young adult S. droebachiensis. These findings contribute to our understanding of the reproductive ecology of S. droebachiensis in habitats with differing food supplies (e.g., kelp beds and barrens). Our results also can be used to improve aquacultural
practices for sea urchins.
Received: 3 June 1998 / Accepted: 2 February 1999 相似文献