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1.
The callianassid shrimp Nihonotrypaea petalura (Stimpson, 1860) is a common member on boulder beaches in Japanese waters. Its burrow morphology was investigated, based on 28 resin casts collected from a steeply sloping beach with dense boulders and 30 from a more gently sloping beach with less dense boulders in Ariake Sound, southern Japan. The structure and dimensions of the burrows from the two beaches were basically the same, and thus a combined mean value could be given to most of their constituent elements. In its entire dimensions, the burrow is greater in lateral extent than depth, with a mean maximum horizontal extension of 145 mm and a mean maximum depth of 119 mm for the shrimp with a mean total length of 31.8 mm. The burrow winds along boulders or cobbles and consists of, from top to bottom, a single surface opening with an ejected mound, a top shaft leading to the uppermost chamber at a mean depth of 48–56 mm, a passage with a regular cross section that is wider than that of the top shaft, and bulbous chambers (mean no.=4.7) with an irregular cross section associated with branches (mean no. per burrow=1.2). Bulbous chambers are much larger than the uppermost chamber and are usually connected by passages, with some directly attached to each other. The combined architecture of these features is unique and relatively simple among the burrows of all callianassid species, the majority of which inhabit bare soft sediments. The structure and function of the N. petalura burrow are discussed in relation to lifestyle.Communicated by T. Ikeda, Hakodate 相似文献
2.
Sand disposal of the painted ghost crab Ocypode gaudichaudii (Decapoda: Ocypodidae): A possible role in courtship 总被引:1,自引:0,他引:1
In 1991/1992, we studied the sand disposal behavior of the painted ghost crabs Ocypode gaudichaudii on the Pacific coast of Panamá. O. gaudichaudii either kick, dump or tamp sand they excavate from their burrows. Here we relate these three kinds of sand disposal to burrow structure and distribution, as well as to crab size and sex. Our objective was to determine whether tamping may be a male courtship signal. Burrows whose owners tamped sand were on average longer, deeper, and higher on the beach than were burrows whose owners kicked or dumped sand. Five burrow shapes were distinguished, with half-spiral and spiral shapes being most common among tamped burrows. All crabs excavated from tamped burrows were males. Tamped burrows peaked in abundance around full and new moons. These observations, together with what is known about mating and breeding behavior of other ghost crabs, suggest that tamping may be involved in O. gaudichaudii courtship. 相似文献
3.
Reproductive biology of a wood-boring isopod, Sphaeroma terebrans, with extended parental care 总被引:1,自引:0,他引:1
M. Thiel 《Marine Biology》1999,135(2):321-333
The isopod Sphaeroma terebrans Bate, 1866 burrows in aerial roots of the red mangrove Rhizophora mangle L. The burrows serve as shelter and as a reproductive habitat, and females are known to host their offspring in their burrows.
I examined the reproductive biology of S. terebrans in the Indian River Lagoon, a shallow lagoon stretching for ∼200 km along the Atlantic coast of Florida, USA. Reproductive
isopods were found throughout the year, but reproductive activity was highest in the fall and during late spring/early summer.
During the latter periods, large numbers of subadults established their own burrows in aerial roots. The average numbers of
S. terebrans per root were high during the fall, but decreased during the winter and reached lowest levels at the end of the summer. Females
reached maturity at a larger size than males, but also grew to larger sizes than the males. The average size of females varied
between 8 and 10 mm, the average size of males between 6.5 and 8.5 mm. The number of embryos female−1 was strongly correlated with female body length. No indication for embryo mortality during development was found. Parental
females (i.e. with juveniles in their burrows) hosted on average between 5 and 20 juveniles in their burrows (range 1 to 59).
Most juveniles found in female burrows were in the manca stage and 2 to 3 mm in body length. Juveniles did not increase in
size while in the maternal burrow, and juveniles of similar sizes could also be found in their own burrows. Males did not
participate in extended parental care, since most of them left the females after copulation. Many females that were born in
the summer produced one brood in the fall and a second during winter/early spring. Females that were born in the fall produced
one brood during spring/early summer, but then probably died. Extended parental care in S. terebrans is short compared to other peracarid crustaceans. It is concluded that this reproductive strategy in S. terebrans serves primarily to shelter small juveniles immediately after they emerge from the female body, when their exoskeleton is
still hardening and their physiological capabilities are still developing. Thus, in S. terebrans, extended parental care probably aids to protect small juveniles from adverse physical conditions in their subtropical intertidal
habitat.
Received: 9 December 1998 / Accepted: 24 June 1999 相似文献
4.
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
5.
The burrows of 4 sympatric associations of alpheid shrimp (Alpheus djiboutensis 1 and 2, and Alpheus sp. A and B) and non-burrowing gobiid fish were studied in the lagoon of a narrow fringing reef, in the northern Red Sea. Epoxy resin casts were used to determine the subterranean structure of burrows. The burrows were irregular, and in close contact with hard objects within the substrate. The number and structure of openings and their daily displacement were type-specific. On the other hand, no type specificity was observed in the deeper parts of the burrow. The mechanism of the formation of new openings by the combined activities of the fish Cryptocentrus sungami and the shrimp A. djiboutensis 2 is described. A positive correlation in the size of the partners seems to be due to competition of fish for larger burrows. 相似文献
6.
O. Anne E. Rasa 《Behavioral ecology and sociobiology》1998,43(2):105-113
Parastizopus armaticeps is a nocturnal subsocial detritivorous desert tenebrionid that produces very few offspring per brood. The two environmental
factors that constrain reproduction, rapid sand desiccation rate and food scarcity, are countered by biparental effort. Males
dig and extend breeding burrows, maintaining their moisture level; females forage on the surface at night for high-quality
detritus, the larval food. This was shown to be a scarce and unpredictable resource for which there is high competition. When
food was supplemented in a field experiment, offspring number and survivorship doubled and burrow failure due to desiccation
dropped from approximately half, the typical failure rate for unsupplemented burrows, to zero. Food supplementation did not,
however, increase larval foodstore size and there was no difference in the size of the offspring produced. Supplemented females
reallocated their time, foraging less and digging more with the male. This change in maternal behaviour patterns resulted
in deeper burrows which remained moist longer, thus extending the larval production period. Female foraging efficiency, particularly
food retrieval speed, determined how much time females could allocate to digging, consequently increasing the reproductive
success of the pair. Burrow depth and sand moisture level at the burrow base were the major correlates of reproductive success,
but the scarcity and unpredictability of high-quality food on the surface and the competition for this resource influenced
the number of offspring indirectly through their effect on female behaviour.
Received: 29 November 1996 / Accepted after revision: 7 December 1997 相似文献
7.
The benthic crustacean Saduria entomon occurs frequently in deeper parts of the Gulf of Gdańsk. It is one of a few species able to survive oxygen deficiencies in
its natural environment. The anaerobic heat production of S. entomon during 40 h of anoxia was determined. Additionally, the effects of size, sex and activity of the organism on its heat production
were investigated. Average heat production of S. entomon was 0.25 ± 0.16 mJ g−1 wet wt s−1 (n=55, avg. length 39 ± 6 mm). The amount of heat produced decreased with increasing body size. The heat production of S. entomon males was greater than that of females ( p<0.05). Specimens kept in chambers with glass beads and water were less active and had lower metabolic rates than those placed
in chambers containing water only (more active). During 40 h of anoxia S. entomon gradually decreased its heat production to 5–16% of aerobic level, demonstrating the high adaptation of this species to changeable
oxygen conditions in the Baltic Sea.
Received: 31 July 1997 / Accepted: 21 January 1998 相似文献
8.
R. J. A. Atkinson 《Marine Biology》1974,25(3):239-252
Diving studies at Fishguard harbour in South Wales (UK) combined with laboratory studies, provided information on the burrowing behaviour of Goneplax rhomboides (L.). Polyester resin casts indicated that burrows had from 1 to 6 openings and tunnels were horizontal at about 10 cm depth, with branches usually at right angles to each other. Burrowing was studied in the laboratory and related to variations in burrow casts taken in the field. Preliminary laboratory experiments suggest that social interactions occur between crabs, but analysis of the spatial distribution of burrows in the field suggested randomness. Burrows in the field showed some similarity of orientation, although the reasons for this were uncertain. 相似文献
9.
M. Thiel 《Marine Biology》1998,132(1):107-116
The reproductive traits of a deposit-feeding amphipod that engages in extended parental care were examined. At the study
site in Lowes Cove, Maine, USA, Casco bigelowi (Blake, 1929) occurred in highest densities in soft sediments just below mean low water (MLW). During most months, the sex
ratio was ≃1. Many females hosted males in their burrows throughout the summer, but after fertilization of females in September,
all adult males disappeared from the study area. In October almost 80% of the females were ovigerous, and in November about
the same percentage was parental, i.e. caring for juveniles in their burrows. The females produced only one brood each in
late fall which they accommodated in their burrows for 2 mo or longer. The average number of juveniles per female was ∼20
in November, and continuously decreased until January. Juveniles reached sizes >10 mm length in the maternal burrows. In early
December the first juveniles were found in their own burrows, but major recruitment took place in late December and January.
It is concluded that for C. bigelowi, the delay of recruitment into the winter months with low predation pressure and the large offspring size at this time are
major advantages gained by extended parental care. C. bigelowi is host to the peritrich ciliate Cothurnia sp. on its gills, and during the summer months >70% of all amphipods had ciliates on their gills. Juveniles still living
in their mother's burrows showed infestation rates similar to that of the parent; those of highly infested mothers were more
heavily infested than those of “clean” mothers. Facilitated epibiont transmission during intimate and long-lasting (2␣mo)
parent–offspring associations may be a consequence of extended parental care.
Received: 25 November 1997 / Accepted: 14 April 1998 相似文献
10.
This study was carried out between January and March 1995 on the intertidal sand flats of Tang Khen Bay, Phuket, South Thailand,
where the soldier crab Dotilla myctiroides (H. Milne-Edwards) occurs in densities of up to 120 m−2. In this bay, long, ribbon-like sand waves (wavelength 40 m, height 0.4 m) are interspersed with shallow pools, running approximately
parallel to the shore. During daylight low-tides, exposure of the sand waves is followed 15 to 20 min later by the emergence
of the crabs which have been buried under the sediment surface during high tide. Their subsequent burrowing and feeding activity
results in the production of large numbers of sand pellets on the sediment surface. Most crabs retreat down their burrows,
and some also plug the burrow entrance, prior to being covered by the incoming tide. The crab burrows have a distinct distribution
on the sand waves. Burrows are most dense at the top of each sand wave, and a band of unburrowed sediment adjoins the adjacent
tidal pools. Crabs are most abundant between mean high-water neap-tide level and mean low-water neap-tide level, where the
median particle size of the surface sediment is ∼2 . Measurements of water-table depth below the sand waves and the exposure
time of the sediment indicated that, where sediment size is suitable, the main factor controlling crab distribution is the
duration of daytime exposure. This observation is in contrast to those of many previous studies, which have suggested that
water-table height and sediment drainage are the main factors controlling the distribution of D. myctiroides.
Received: 14 January 1998 / Accepted: 6 May 1999 相似文献
11.
Variation of the amplification effect of burrows of the leptodactylid frog Eupsophus emiliopugini on conspecific calls generated externally was investigated. Advertisement calls broadcast through a loudspeaker placed in
the vicinity of a burrow were monitored with small microphones positioned inside and outside the cavity. For 150 presentations
of calls of 15 individuals in 12 burrows, 134 were amplified and 16 were attenuated (range –6–13 dB). The fundamental resonant
frequency of burrows, measured with broadcast noise and pure tones, averaged 814 Hz (range 302–1361 Hz) and covaried with
burrow length. The dominant frequency of the calls of burrow occupants (average 1062 Hz, range 636–1459 Hz) was not correlated
with the fundamental resonant frequency of these cavities. In burrows with low resonant frequencies, externally broadcast
calls with high dominant frequencies were attenuated, or amplified to a lower extent than calls with lower dominant frequencies.
The dominant frequencies of the calls experienced shifts towards the burrows’ fundamental resonant frequencies. The amplification
of calls inside burrows of E. emiliopugini exhibits manifest variability, with considerable potential for facilitating acoustic interactions in this species.
Received: 18 July 1999 / Received in revised form: 19 July 1999 / Accepted: 25 July 1999 相似文献
12.
We examined the mating behaviour of the New Zealand ocypodid crab Macrophthalmus hirtipes in the laboratory between February and June 1998. This species has a discrete breeding season. Mating and moulting were not
linked and only intermoult females with mobile gonopore opercula were attractive to males. Allometry and compatibility of
gonopods and gonopores of different-sized crabs was investigated. Under laboratory conditions, the opercula of intermoult
females remained mobile on average for 11.4 d, but the duration of receptivity did not appear to be under female control.
The operational sex ratio in the laboratory fluctuated greatly, but was always male-dominated. During the period of opercular
mobility, females mated many times with several different males. Matings in the absence of burrows were relatively short (mean
duration = 23 min, max. = 122 min) and the mating behaviour of M. hirtipes lacked courtship and mate-guarding. Males used a search-intercept method to acquire mates, with very low levels of intrasexual
competition. There was no evidence of mate preference in M. hirtipes, and males spent just as long mating with ovigerous females as with non-ovigerous ones. Although M. hirtipes has ventral-type spermathecae, as do several other ocypodid crabs, it is unclear whether this promotes last-male sperm precedence.
The role of burrows in modifying the mating behaviour of M. hirtipes in the field remains to be established.
Received: 7 January 2000 / Accepted: 5 June 2000 相似文献
13.
Few studies conducted in crustaceans have demonstrated how habitat features could shape the mating systems. Here, the burrow of Neohelice granulata was considered as a resource used for mating, and its architecture was characterized in two contrasting study sites: Mar Chiquita Lagoon (MCL), an estuary composed of muddy sediments, and San Antonio Oeste (SAO), a marine bay composed of gravel sediment. Burrow features differed between study sites and occupant gender. Large males constructed burrows with a chamber in MCL and with a widened entrance in SAO, while small males constructed the same narrow burrows as females at both study sites. Field experiments demonstrated that burrows with chambers or widened entries are places used for copulation, although successful post-copulatory guarding was displayed only in those with chambers. The intensity of the agonistic encounters and the success of males in winning resources (burrows/females) also depend on the habitat characteristics. N. granulata shows a resource defense mating system where males employ different mating strategies according to the burrow architecture to ensure mating success. 相似文献
14.
Pablo D. Ribeiro John H. Christy Rebecca J. Rissanen Tae Won Kim 《Behavioral ecology and sociobiology》2006,61(1):81-89
Courting male fiddler crabs Uca terpsichores (1 cm carapace width) sometimes build mounds of sand called hoods at the entrances to their burrows. Males wave their single
enlarged claws to attract females to their burrows for mating. It was shown previously that burrows with hoods are more attractive
to females and that females visually orient to these structures. In this study, we test whether males also use their hoods
to find their burrows. We first determined the maximum distance that males can see and find a burrow opening without a hood.
Males were removed from their burrows and placed on the sand at a range of distances from a burrow opening. If they were more
than about 8 cm (seven units of eye-height) away, they were unable find the burrow. In contrast, males that were burrow residents
used a non-visual path map to return to their burrows from much greater distances. To determine if hoods help males find their
burrows when there are errors in their path maps, we moved residents 1–49 cm on sliding platforms producing errors equal to
the distances they were moved. Males with self-made hoods or hood models at their burrows relocated their burrows at significantly
greater distances than did males with unadorned burrows. Hood builders also relocated their burrows faster. Hence, hoods have
two functions: they attract females and they provide a visual cue that males use to find their burrows quickly and reliably
when their path maps fail.
An erratum to this article can be found at 相似文献
15.
J. B. Lewis 《Marine Biology》1998,130(4):651-662
Dipolydora armata (Langerhans, 1880) is a small (4 to 5 mm) spionid polychaete found burrowing in the calcareous hydrozoan Millepora complanata Lamarck, 1816, on coral reefs at Barbados, West Indies. It excavates complex networks of interconnecting burrows and forms
aggregations of worms in cavities within branches of the coral. Adult worms have a mixed feeding mode (suspension feeding
and deposit feeding). Size–frequency distributions of worms in branch samples suggest that they mature in a single year and
that reproduction occurs throughout the year. Burrow openings on the surface of the coral develop distinctive, erect spines
caused by combined growth of worm tubes and host tissue. Millepore zooids were absent in the vicinity of tube openings and
on spines, and thus the potential feeding surface of the coral will be reduced in heavily colonized branches. Burrows and
openings were densest at the bases of millepore branches where weakening of the skeleton would be expected to occur. The absence
of openings near the branch tips suggests difficulty in larval settlement there, amongst stinging zooids. Reproduction␣and
larval development of the worms were examined, and a sequence of larval stages from one to 20 segments and a juvenile stage
of 22 segments are described. Eggs are deposited in brood sacs attached to the burrow wall, and the larvae feed upon nurse
eggs (adelphophagy). The presence of larvae and juveniles occurring free in the burrows suggests that larval development may
be completed within the host coral as an alternative or in addition to a planktonic larval phase. Lack of provisional larval
setae, early development of adult capillary setae, production of special spermatophores and a protracted breeding cycle in
D. armata are all traits which would favour complete development within the host skeleton.
Received: 6 March 1997 / Accepted: 25 October 1997 相似文献
16.
The behaviour of the Caribbean Corallianassa longiventris and the Mediterranean Pestarella tyrrhena, two burrowing thalassinideans, was studied in situ and in laboratory aquaria. Burrows of C. longiventris were closed most of the time; they consist of a deep U (down to 1.5 m) with upper and deeper chambers, some of them filled
with macrophyte debris. The burrows of P. tyrrhena reached down to a maximum depth of 54 cm and consisted of a shallow U with a mound and a funnel, and a spiral shaft from
which several, often debris-filled chambers branched off. The appearance of C. longiventris at the sediment surface to collect debris is strongly triggered by wave swell or odours from plant and animal juices; its
burrows are opened within 10 min. The surface activity of P. tyrrhena was relatively less frequent and less predictable. Inside the burrows, both species exhibited different patterns of time
allocated to 25 defined behavioural states. After being offered seagrass debris, P. tyrrhena spent relatively less time manipulating this debris, but it handled sediment more often than C. longiventris. During frequent mining events, both species showed sediment-sorting behaviour, which brought a parcel of sediment in close
contact with the mouthparts; some of this sediment may be ingested because the fecal rods produced by both shrimps contain
very fine sediment particles. Seagrass debris is irregularly tended by P. tyrrhena after its introduction into the chambers. Such material ultimately becomes buried. Corallianassa longiventris frequently returns to its debris chambers to pick up pieces of seagrass, which are subsequently cut with the chelae or ripped
with the third maxilliped and then transported to another empty chamber nearby. Pieces become smaller with time and show curved
cutting edges and bite marks. After 100 to 140 days, 2 to 6 g(dw) seagrass debris are consumed in this manner by individuals
of this species. The debris-related behaviour of P. tyrrhena probably enriches the sediment around the burrow for stochastic encounters during later mining events. Such an indirect benefit
may also be effective on a population level because other individuals may also encounter this buried nutrient source.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
17.
In a Kenyan mangrove, we studied the interactions between the gastropod Terebralia palustris and the crab Neosarmatium smithi when foraging on decaying mangrove leaves. Interactions are considerable on account of their wide overlap in zonation (Rhizophora mucronata belt), food items (mangrove leaves) and activity window (diurnal low water). The snails find a leaf by a systematic transecting
of the platform and eat the leaf after crawling on to it, usually en masse. The crabs rarely venture beyond 80 cm from their
burrows, and once they find a leaf they quickly drag it back into their burrow, probably to reduce the strong intra-specific
competition. A crab is able to drag a leaf away even if a number of snails are already feeding on it, by strongly pulling
the leaf away or by pushing the snails off the leaf. The success of the “thief ” depends on both the crab's size and the number
of snails on the leaf.
Received: 25 July 1999 / Accepted: 27 April 2000 相似文献
18.
R. W. Brill B. A. Block C. H. Boggs K. A. Bigelow E. V. Freund D. J. Marcinek 《Marine Biology》1999,133(3):395-408
We measured the horizontal and vertical movements of five adult yellowfin tuna (Thunnus albacares, estimated body mass 64 to 93 kg) near the main Hawaiian Islands, while simultaneously gathering data on oceanographic conditions
and currents. Fish movements were recorded by means of ultrasonic depth-sensitive transmitters. Depth–temperature and depth–oxygen
profiles were measured with vertical conductivity–temperature–depth (CTD) casts, and the current-velocity field was surveyed
using an acoustic Doppler current profiler (ADCP). Large adult yellowfin tuna spent ≃60 to 80% of their time in or immediately
below the relatively uniform-temperature surface-layer (i.e. above 100 m), a behavior pattern similar to that previously reported
for juvenile yellowfin tuna, blue marlin (Makaira nigricans), and striped marlin (Tetrapturus audax) tracked in the same area. In all three species, maximum swimming depths appear to be limited by water temperatures 8 C°
colder than the surface-layer water temperature. Therefore, neither large body mass, nor the ability to maintain elevated
swimming-muscle temperatures due to the presence of vascular counter-current heat exchangers in tunas, appears to permit greater
vertical mobility or the ability to remain for extended periods below the thermocline. In those areas where the decrease in
oxygen with depth is not limiting, the vertical movements of yellowfin tuna, blue marlin and striped marlin all appear to
be restricted by the effects of water temperature on cardiac muscle function. Like juvenile yellowfin tuna, but unlike blue
marlin and striped marlin, adult yellowfin tuna remained within 18.5 km of the coast and became associated with floating objects,
including anchored fish-aggregating devices (FADs) and the tracking vessel. Like juvenile yellowfin tuna, large adult yellowfin
repeatedly re-visit the same FAD, and appear able to navigate precisely between FADs that are up to 18 km apart. The median
speed over ground ranged from 72 to 154 cm s−1. Neither speed nor direction was strongly influenced by currents.
Received: 27 March 1998 / Accepted: 13 November 1998 相似文献
19.
The annual occurrence of hypoxia (<25% oxygen saturation) in the bottom waters along the Swedish west coast coincides with
the postlarval settlement of Norway lobster, Nephrops norvegicus (L.). This study investigates behaviour and the experimental effects of low oxygen concentrations in juvenile N. norvegicus of different ages. All experimental individuals were reared to the juvenile (postlarval) stage in the laboratory and then
given sediment as a substratum. Behavioural responses to low oxygen concentrations were tested in early and late Postlarvae
1 exposed to normoxia (>80% oxygen saturation, pO2 > 16.7 kPa), moderate hypoxia (30% oxygen saturation, pO2 = 6.3 kPa) and hypoxia (25% oxygen saturation, pO2 = 5.2 kPa). The experiments were run for a maximum period of 24 h or until individuals died. Behaviour was studied using
sequential video recordings of four behavioural activities: digging, walking, inactivity or flight (escape swimming up into
the water column). Behaviour and mortality changed with lowered oxygen concentrations; energetically costly activities (such
as walking) were reduced, and activity in general declined. In normoxia, juveniles initially walked and then burrowed, but
when exposed to hypoxia they were mainly inactive with occasional outbursts of escape swimming. To increase oxygen availability
the juveniles were observed to raise their bodies on stilted legs (similar to adults in hypoxic conditions), but oxygen saturations
of 25% were lethal within 24 h. The results suggest that the main gas exchanges of early postlarval stages occur over the
general body surface. Burrowing behaviour was tested in Postlarvae 1 and 2 of different ages held in >80% oxygen saturation
for 1 wk. The difference in time taken to complete a V-shaped depression or a U-shaped burrow was measured. The results showed
a strong negative relationship between postlarval age and burrowing time, but all individuals made a burrow. Juveniles were
more sensitive to hypoxia than adults. Thus, the possible consequences of episodic hypoxia for the recruitment of Nephrops norvegicus and for the recolonization of severely affected areas are discussed.
Received: 4 August 1996 / Accepted: 11 October 1996 相似文献
20.
The aim of this study was to determine whether the composition of the demersal fish fauna in coastal marine waters in temperate
Australia changes markedly with increasing water depth and distance from the shore and whether the composition of the fish
fauna in water depths of 5 to 35 m undergoes cyclic, seasonal changes. Samples of demersal fishes were therefore collected
by trawling over the predominantly sandy substrate at nine sites located in water depths of 5 to 15 m or 20 to 35 m and within
20 km of the shore in four regions along ∼200 km on the lower west coast of Australia. The sampling regime involved trawling
for fishes at each site at night in seven consecutive seasons between the summer of 1990/1991 and winter of 1992. A total
of 72 435 fishes, representing 77 families, 143 genera and 172 species was caught. The compositions of the fish faunas in
offshore waters with depths of 5 to 35 m were shown to differ markedly from those previously recorded for nearshore marine
waters in the same regions. However, as some species, such as Sillago burrus, S. vittata, S. bassensis and Rhabdosargus sarba, increase in size, they move out from their nursery areas in nearshore waters into deeper and more offshore waters, where
spawning occurs. Ordination showed that, in each of the four regions, the composition of the fish fauna in depths of 5 to
15 m differs from that in depths of 20 to 35 m. This difference is attributable to the fact that some species, such as S. burrus, S. vittata and Upeneichthys lineatus, are far more abundant in depths of 5 to 15 m, whereas other species, such as S. robusta, U. stotti and Lepidotrigla modesta, occur predominantly in depths of 20 to 35 m. However, the samples collected from the single site that was inshore but in
deeper water demonstrate that the composition of the fish fauna is influenced by distance from shore as well as by water depth.
The compositions of the fish faunas differed with latitude, largely due to the fact that some subtropical species, such as
Polyspina piosae, S. burrus and S. robusta, did not extend down into the more southern regions. Ordination also showed that the composition of the fish faunas at all
but one of the nine sites underwent pronounced and consistent cyclic, seasonal changes. This seasonal cyclicity at the different
sites was attributable to sequential patterns of immigrations and emigrations by a number of fish species during the course
of the year. These seasonal migrations involved, inter alia (1) movements of certain species from their nursery areas into
these deeper waters, e.g. S. bassensis and Scobinichthys granulatus; (2) migrations into and off the sandy areas of the inner continental shelf, e.g. Arnoglossus muelleri; (3) migrations to spawning areas, e.g. Sillago robusta; and (4) movements into areas where detached macrophytes accumulate in winter, e.g. Cnidoglanis macrocephalus and Apogon rueppellii.
Received: 21 August 1998 / Accepted: 9 February 1999 相似文献