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1.
Territorial Parma microlepis (Günther) (Pomacentridae) were collected at different depths, at three sites in each of four estuaries near Sydney, Australia.
Element concentrations were measured by induc- tively-coupled–plasma mass spectrometry. Significant differences in concentrations
of Mn and Ba were found in the otoliths of fish sampled in different depth strata, with concentrations generally greatest
in fish found in water <4 m deep. Depth-related differences varied among estuaries (e.g. 0 to 1.2 μg Ba g−1 otolith). In most estuaries there was a negative linear relationship between concentrations of Mn and Ba in otoliths and
actual depth. Great variation was found within an estuary among sites separated by 0.5 to 3 km. In the eye lenses, concentrations
of Rb differed according to depth of capture of fish. The age of fish (1+ to 34 yr) had no influence on the concentrations
of elements in otoliths or lenses. Multivariate comparisons of elemental composition (= fingerprints) detected significant
differences among depth strata. Fish collected from shallow water had the clearest multivariate classification according to
depth. There was a close match between our shallow strata and the average depths reached by low-salinity/high-temperature
estuarine plumes. The element composition of whole otoliths and lenses represents average concentrations experienced by the
fish. The temporal resolution of differences in ambient conditions is likely to be coarse in the fish (i.e. months to years).
Received: 9 April 1999 / Accepted: 29 February 2000 相似文献
2.
S. G. Dove 《Marine Biology》1999,134(4):653-663
The eye lenses of Parma microlepis from the rocky barrens of Sydney (New South Wales, Australia) were found to contain Ba, Hg, Rb, and Sr at concentrations
above the quantitative detection limits of solution-based inductively-coupled plasma–mass spectrometry (ICP–MS). Lenses were
separated into the hard central nucleus and the softer surrounding cortex. Nuclei contained lower (equal for Ba) concentrations
of these metals. Biochemical analysis of the protein composition of these lenses revealed differences in the ratio of γ-crystallin
to β-crystallin in the lens nucleus and cortex. These changes were shown to be attributable both to protein degradation and
changes in protein synthesis as fish age. Such changes may lead to the loss of sequestered metals from older cell layers,
or change the affinity of new layers for particular trace metals. Differential binding affinities of these crystallins may,
therefore, partially account for trace-metal differences observed in the lens nucleus and cortex.
Received: 13 November 1998 / Accepted: 23 April 1999 相似文献
3.
In recent years, mussels have already become commercially important seafood species worldwide. Mussels accumulate a wide range
of metals in their soft tissue. Thus, the determination of accumulated concentrations of heavy metals, such as Pb, Cd, Hg,
and As, in mussels is essential because of their usage as seafood and the potential adverse effects of their consumption on
human health. In this review, these issues are presented and discussed using the Mediterranean mussel Mytilus galloprovincialis as an example. M. galloprovincialis is very efficient at converting low value victuals into high quality animal protein. The production of M.
galloprovincialis in Mediterranean countries has been increasing rapidly, but Spain is still the largest producer of mussels. Only China has
a larger production of these mussels than Spain. M. galloprovincialis is a filter feeding animal and accumulates a wide range of metals from their environment. The metal concentrations in the
soft tissue of M.
galloprovincialis are indicators of marine ecosystems contamination. In the same time, the bioaccumulation of heavy metals remains an issue
concerning the consumption of mussels. Thereby, the Cd, Pb, Hg, and As concentration measurement in mussel soft tissue as
a seafood have become significant. A review of literature data revealed large variations in the Cd, Pb, Hg, and As concentrations
in M. galloprovincialis from their endemic areas, e.g., Mediterranean, Adriatic, and Black Sea, and the concentrations of these toxic metals were
generally in the following order: As > Pb > Cd > Hg. The guidelines on heavy metals for seafood safety set by different countries
and associations are reviewed. Comparison of the published data with European legislation showed that the levels of the heavy
metals generally did not exceed the existing limits in all the mussels analyzed, excluding mussels from hot spots, such as
lagoons and harbors, in the Mediterranean, Adriatic, and Black Sea. 相似文献
4.
K. A. Tricklebank 《Marine Biology》2000,136(2):337-348
Parma microlepis (Günther) were collected from Malabar, an urban location close to the centre of Sydney, Australia, and from Jervis Bay, a
reference location 170 km south of the city centre. At each location, fish were collected from two sites separated by 100
to 200 m. The ultrastructure of normal liver tissue is described based on 20 female fish collected from Jervis Bay, where
fish are known to be exposed to low levels of organochlorine contaminants. Alterations in the endoplasmic reticulum, mitochondria,
lysosomes and nuclei of hepatocytes were identified and quantified in the liver tissue of fish from this location and compared
to alterations in 20 female fish collected from Malabar, where fish are exposed to higher concentrations of organochlorine
pesticides such as DDT compounds. There were significant differences in the percentage of hepatocytes with swollen mitochondria
(F = 124.025, df = 2, 2, P = 0.008) and atypical nuclei (F = 22.198, df = 2, 2, P = 0.043) between sites (100 to 200 m apart), but there were no clear differences between the percentage of structural alterations
in the hepatocytes of P. microlepis from Jervis Bay and Malabar. Associations between liver morphology and the organochlorines aldrin, dieldrin, DDE and chlordane
were examined using a Pearson correlation matrix. Significant correlations were detected between the percentage of hepatocytes
with dilated endoplasmic reticulum and the concentrations of the pesticide aldrin (r = 0.600, df = 11, r
crit(α = 0.05) = 0.553). Significant associations were also detected between the percentage of hepatocytes with disorganised endoplasmic
reticulum and the concentrations of dieldrin and DDE residues in fish (r = 0.576, r = 0.567, respectively, df = 13, r
crit (α = 0.05) = 0.514). However, there was little evidence that ultrastructural alterations in fish responded to increasing concentrations
of these pesticides in a consistent dose-response manner.
Received: 20 October 1998 / Accepted: 24 November 1999 相似文献
5.
The levels and burdens of Cd, Zn, Cu and Hg were measured in the dorsal mantle, digestive gland and gonads of the squid Illex argentinus, from the Southwest Atlantic Ocean. Mature and immature individuals of both sexes were analysed. Correlations of heavy metal
concentrations and burdens with sex and food habits were studied. The highest metal levels were found, particularly for Cd,
in the digestive gland, which attained a concentration of up to 270 μg g−1 (wet weight). Dorsal mantle and gonads exhibited the same order of metal enrichment: Zn>Cu>Cd. Zinc and Cu levels were higher
in ovaries than in testes and varied with the stage of maturation. The dorsal mantle exhibited the lowest heavy metal concentrations.
Mercury levels were below the detection limit of the method in all the tissues analysed.
Received: 7 September 1999 / Accepted: 9 March 2000 相似文献
6.
We assessed the efficacy of tetracycline, calcein and strontium chloride for validating the periodicity of otolith growth-increments
in eight species of tropical marine gobies (family Gobiidae). We compared the number of fishes in which the otoliths were
successfully marked when each of these chemicals was administered by intraperitoneal injection or immersion bath at a range
of doses and immersion times. All three chemicals could produce a detectable mark in the otoliths of five reef-flat gobies,
Asterropteryx semipunctatus, Amblygobius bynoensis, Istigobius goldmanni, Valenciennea muralis and Amblygobius phalaena; however, tetracycline injection at 50 mg kg−1 is recommended because it produced a brighter otolith mark than calcein and is cheaper and quicker to detect than strontium
chloride. Calcein immersion treatment of 125 mg l−1 for 24 h was the most successful treatment for two estuarine gobiids, Favonigobius reichei and Glossogobius biocellatus. No treatment produced a detectable mark in the otoliths of the coral-dwelling goby Gobiodon histrio. Adequate care in the preparation of otoliths was found to be essential for detection of the validation mark produced by
tetracycline and calcein. Otolith growth-increments were deposited daily in the seven species of goby for which validation
was possible.
Received: 15 October 1999 / Accepted: 15 June 2000 相似文献
7.
Physicochemical properties, total metals and metal species were investigated in surface soil samples from six urban dumpsites within Akwa Ibom State, Nigeria. Results obtained indicated that Pb, Cd and Cr levels were higher in the dry season than in wet season, whereas Ni levels were higher during the wet season. Soil pH, organic matter and cation-exchange capacity (CEC) showed higher values in wet season than in dry season, whereas sand and clay levels were higher in the dry season. Speciation analysis showed the principal fraction of the metals to be Pb (reducible), Cd (acid extractable) and Ni (residual), whereas Cr existed in the residual fraction during the dry season and in the acid-extractable fraction during the wet season. Soil pH was positively correlated at p<0.1 with all metals in both seasons, sand was negatively correlated with the metals in both seasons, and CEC was negatively correlated with all metals in both seasons, except Pb in the wet season. Organic matter showed variable relationships with metals in both seasons. Seasonal variations affected metal availability and physicochemical properties of the soil. Total metal concentrations followed the order Pb>Ni>Cd>Cr, whereas their bioavailability followed the trend Cd>Pb>Cr>Ni. 相似文献
8.
Effects of specimen handling and otolith preparation on concentration of elements in fish otoliths 总被引:2,自引:0,他引:2
The use of otolith chemistry as a tool for analysing the biology of fishes assumes that the procedures used to collect and
prepare otoliths for analysis do not alter their composition. With otoliths of Nemadactylus macropterus, Hoplostethus atlanticus, and Rhombosolea tapirina, we show that this assumption is not valid for the elements that can be detected using electron-probe microanalysers (those
present at concentrations greater than ≃100 parts per million): all six elements routinely measured using these techniques
were affected by at least one post-mortem procedure tested. Measured concentrations of calcium and strontium were relatively
insensitive to most procedures tested, whereas concentrations of sodium, potassium, sulphur and chlorine were affected substantially
by many commonly used procedures. The ease with which otolith composition could be modified post-mortem suggests that apparent
geographic, habitat-specific or ontogenetic differences in otolith composition should be interpreted with extreme caution
because of easily induced artefacts and the problem of pseudo-replication associated with the ways otoliths are sampled and
prepared for analysis.
Received: 23 September 1996 / Accepted: 11 April 1998 相似文献
9.
Metallothionein-like proteins (MTLs) have been measured by differential pulse polarography every two months during a period
of two and half years in the marine bivalve Macoma balthica from two locations of the Western Scheldt Estuary. The MTL concentrations (0.85 to 7.81 mg g−1 dry wt) are comparable to most values found for other marine invertebrates. These concentrations vary significantly with
the seasons (higher in winter, lower in summer), which is mainly due to body weight fluctuations. Strong correlations exist
between MTL and metal levels. Upon short-term exposure to a mixture of Cd, Cu and Zn, there are on average significant MTL
increases, but important seasonal variations have been observed: in winter, the clams are more sensitive to metals, uptake
more Cd and Cu and induce more MTL than during the warmer months.
Received: 16 May 1997 / Accepted: 6 June 1997 相似文献
10.
Element analysis of the annual increments in a longitudinal section from the tusk of a female dugong Dugong dugon (Müller) from Exmouth, Western Australia, was carried out by X-ray fluorescence-imaging, inductively coupled plasma-atomic
emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS). Nine elements (Ba, Ca, Fe, Li,
Mg, Na, P, Sr and Zn) were present in concentrations amenable to determination by these techniques. Most elements revealed
both long-term trends and shorter, year-to-year, variations. For example, sodium concentrations increased from 0.55 to 0.72%
with the age of the dugong. Strontium concentrations (mean 0.17%) were closely correlated (r = 0.86) with those of barium (mean 4.5 mg kg−1). Zinc concentrations increased from ∼70 to 170 mg kg−1 with dugong age, but also showed shorter-term fluctuations of ∼30 mg kg−1 that were correlated (r = 0.41) with mean annual Fremantle sea level (a measure of the Southern Oscillation Index and strength of the Leeuwin Current).
The concentrations of the elements and correlations with year and between pairs of elements are discussed.
Received: 10 January 1997 / Accepted: 21 April 1997 相似文献
11.
Falusi Bamidele Ayodeji Olanipekun Edward Olorunsola Olanisebe Deborah Olukemi 《毒物与环境化学》2013,95(9):1665-1672
Transfer coefficients of the four metals As, Cd, Hg, and Pb were determined in the leaves and barks of Morinda lucida collected in Nigeria, with the view to quantify relative differences in the bioavailability of the metals to these parts of the plant. Samples were acid digested and the levels of the metals in the digestates were determined using an atomic absorption spectrophotometer. Certain properties of the soils, i.e., pH, clay fraction, electrical conductivity, cation exchange capacity, and organic matter, were also determined. The latter influence the bioavailability of the metals. All parameters correlated with the concentrations of the metals in soils. Transfer coefficient values recorded for Cd and Pb in various tissues of M. lucida Benth were within the expected ranges, while those of As and Hg showed elevated topsoil concentrations of metals. The order of bioavailability of the metals and their bioaccumulation in the tissues of M. lucida Benth was Hg > Cd > As > Pb. Stem barks of the plant showed the least bioaccumulation of all four metals and hence are most suitable for therapeutic purposes. Vegetative parts of M. lucida Benth used for therapeutic purposes should be sourced at sites that will give low transfer coefficient in order to reduce human exposure to toxicity associated with ingestion of heavy metals. 相似文献
12.
Aleksandra Wilk Elżbieta Kalisińska Danuta I. Kosik-Bogacka Maciej Romanowski Jacek Różański Kazimierz Ciechanowski Marcin Słojewski Natalia Łanocha-Arendarczyk 《Environmental geochemistry and health》2017,39(4):889-899
Heavy metals, including cadmium (Cd), lead (Pb) and mercury (Hg) act as nephrotoxic agents, particularly in the renal cortex. The aim of the study was to determine the concentrations of Cd, Pb and Hg in kidneys removed from patients due to lesions of various etiologies and from patients after the rejection of transplanted kidneys. Additionally, we determined the influence of selected biological and environmental factors on the concentrations of toxic metals. The study material consisted of kidneys with tumor lesions (n = 27), without tumors (n = 7) and its extracted grafts (n = 10) obtained from patients belongs to the north-western areas of Poland. The determined metal concentrations in the renal cortex and medulla may be arranged in the following descending order: Cd > Pb > Hg. The highest concentrations of Cd and Hg were found in the cortex, while the maximum content Pb was observed in the medulla. Significant correlations were found in the concentrations of the same metals between cortex and medulla and between Pb and Hg in the renal medulla. Pb content was higher in the renal medulla of men than in the cortex of the elderly (above 60 years of age). The highest concentrations of Pb and Hg were found in the cortex and medulla, of the kidneys had not neoplastic changes, and lower content of these metals were found in the extracted kidney grafts. In summary, renal grafts accumulate less heavy metals than cancerous kidneys, what could have been caused by immunosuppressors taken by the graft recipients. Moreover, sex, age and smoking are key factors responsible for xenobiotics concentrations. 相似文献
13.
Strontium (Sr) and calcium (Ca) contents in the otoliths of yellow and silver European eels [Anguilla anguilla (L.)] collected from coastal waters of the Baltic Sea and a freshwater lake in Sweden were examined by wavelength dispersive
X-ray spectrometry with an electron microprobe. The mean Sr/Ca ratios from elver check to otolith edge were significantly
higher for the eels from coastal waters (5.39 ± 1.09‰) than for those from the lake (0.71 ± 0.89‰). The evidence indicates
that European eels in the Baltic Sea do not necessarily migrate into freshwater streams during the growth phase.
Received: 30 September 1999 / Accepted: 6 April 2000 相似文献
14.
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
15.
Chukwujindu M. A. Iwegbue Godwin E. Nwajei Jude E. Ogala Chukwudumebi L. Overah 《Environmental geochemistry and health》2010,32(5):415-430
The concentrations of trace metals (Cd, Pb, Cu, Cr, Fe, Ni, Zn and Co) were studied in soil profiles of eight municipal waste
dump sites in Warri metropolis. The results indicate that concentrations of trace metals varied widely among the different
dumpsites and decreased with depths in a studied soil profile. The accumulation pattern for the heavy metals in the soil profiles
follows the order: Fe > Pb > Mn > Co > Cr > Zn > Ni > Cu > Cd. The concentrations of metals found in these sites was below
the Canadian remediation criteria for land for agricultural, residential and commercial/industrial purposes except for the
cadmium levels in some sites that exceeded criterion values for agricultural and residential. In such sites, remedial actions
are required before any form of chosen development can take place. The levels of heavy metals found in these dump sites were
higher than that of the control site. The examined metals showed no significant correlation with soil physicochemical properties
at the surface horizon, which is suggestive evidence that these metals arise from anthropogenic input. 相似文献
16.
The spatial, diel and tidal variability in the abundance of piscivorous fishes and their teleost prey, and the dietary composition
of predatory fishes were investigated in beds of Heterozostera tasmanica within Port Phillip Bay, Australia, from September 1997 to February 1998. Predatory and prey fish assemblages were sampled
from beds of H. tasmanica at three locations during each combination of diel (day and night) and tidal (high and low) cycles. Pelagic and benthic crustaceans
represented >60% by abundance of the diets of all predatory fishes. Seven species, 54% of all predatory fishes, were piscivorous.
These piscivores consumed individuals from seven families, 36.8% of the fish families being associated with seagrass. Western
Australian salmon, Arripis truttacea (Arripidae) (n = 174) and yank flathead, Platycephalus speculator (Platycephalidae) (n = 46) were the most abundant piscivores. A. truttacea consumed larval/post-larval atherinids, gobiids and sillaginids. P. speculator consumed late-juvenile/adult atherinids, clinids and gobiids. While the abundances of piscivores varied between locations
(P < 0.001) and diel periods (P = 0.028), the relative differences in piscivore abundance between sites and diel periods were not consistent between tides.
The abundances of A. truttacea varied in a complex way amongst sites, diel period and tidal cycle, as shown by a three-way interaction between these factors
(P = 0.026). Only during diurnal periods at St. Leonards was the abundance of A. truttacea significantly higher during high than low tides (P < 0.001). During the other diel periods at each site, the abundance of A. truttacea did not vary. P. speculator was significantly more abundant nocturnally (P = 0.017). The abundance of small (prey) fishes varied significantly amongst sites (P < 0.001). During the day, the abundance of small fishes did not vary between high and low tides (P = 0.185), but their nocturnal abundance was greater during low tide (P < 0.001). Atherinids (n = 1732) and sillaginids (n = 1623) were the most abundant families of small fishes. Atherinids were significantly more abundant nocturnally (P = 0.005) and during low tides (P = 0.029), and varied significantly amongst sites (P < 0.001). Sillaginids varied significantly only amongst sites (P < 0.001). Seagrass beds provide a foraging habitat for a diverse assemblage of predatory fishes, many of which are piscivorous.
Anti-predator behaviour and amongst-location variability in abundances of piscivorous fishes may explain some of the diel
and tidal, and broad-scale spatial patterns in small-fish abundances.
Received: 23 July 1999 / Accepted: 18 January 2000 相似文献
17.
S. K. Wilson 《Marine Biology》2000,136(3):431-437
An evaluation of the dietary resources available to, and selected by, blennies of the tribe Salariini was used to assess
their trophic status on the Great Barrier Reef. Gut-content analysis of nine species of blennies found detrital aggregates
to be the dominant item ingested. Samples of the dietary resources available to one of these species, Salarias patzneri, were compared biochemically. Of the two main dietary categories (detrital aggregates and filamentous algae), detrital aggregates
were the major resource available, accounting for 53 ± 4.6% (SE) of the organic matter present. The mean C:N values for detrital
aggregates (17.2 ± 0.8) and filamentous algae (20.0 ± 1.8) were very similar, as were protein concentrations (1.8 ± 0.1 and
2.1 ± 0.1 μg mg−1, respectively). However, mean carbohydrate concentrations were much lower in the aggregates than the filamentous algae (19 ± 2
and 76 ± 13 μg mg−1, respectively). Comparison of the inorganic particles ingested to those available indicated that S. patzneri selectively fed on particles <125 μm, (predominantly detrital aggregates) and avoided particles >250 μm, (predominantly algal
filaments). The patterns of resource availability, nutritional quality and selectivity suggest that salariin blennies utilise
detrital aggregates as their primary dietary resource.
Received: 24 May 1999 / Accepted: 29 November 1999 相似文献
18.
An ecological survey was carried out to determine the sediment concentrations of nutrients and heavy metals and bioaccumulation of heavy metals in fish and shrimp including tilapia (Oreochromis mossambicus×O. nilotica), grey mullet (Mugil cephalus), gei wai shrimp (Metapenaeus ensis) and caridean shrimp (Macrobrachium nipponensis) in the traditional tidal shrimp ponds (gei wais) of Mai Po Nature Reserve, Hong Kong. The sediments collected from the landward sites contained higher nutrient contents, as well as zinc (Zn), chromium (Cr), copper (Cu), nickel (Ni) and cadmium (Cd) than those collected from the seaward sites, but vice versa for lead (Pb) and mercury (Hg). However, the concentrations of all metals were exceptionally high in the two sites located outside the reserve, suggesting that waters from Deep Bay might be the possible source of metal contamination affecting the reserve. All metals studied seemed to accumulate in the viscera of fish. Body size was the determining factor for the accumulation of heavy metals in caridean shrimp and gei wai shrimp but not fish. Concentrations of the metals studied in tissues of grey mullet and gei wai shrimp were found to be safe for human consumption. Concentrations of Cr in tilapia whole body (0.68–1.10 mg kg−1 wet weight) were close to or over the guideline value of 1 mg kg−1 set by the Food Adulteration (Metallic Contamination) Regulations of Hong Kong. Tilapia flesh and small caridean shrimp collected from gei wais were contaminated by Cr and Pb but still fit for human consumption. Caution is required if large caridean shrimp is to be consumed in large amounts continuously because the concentration of Pb exceeded the maximum permitted concentration (6 mg kg−1). The rather high Cr concentrations in tilapia whole body should not be overlooked as the fish will serve as a food source for migratory birds visiting the site. 相似文献
19.
The European fanworm Sabella spallanzanii (Gmelin, 1791) was recently introduced to Port Phillip Bay and is now a conspicuous component of most benthic communities.
Reproduction of the worm was investigated in a population at Queenscliff over a 2 yr period (October 1995 to October 1997)
using gonadal histology. The worms are dioecious (sex ratio 1:1, n=250), and attained sexual maturity at ∼50 mm body length. Reproductive periodicity followed a distinct annual cycle, and
spawning proceeded through an extended autumn/winter period. Spawning was broadly synchronous between sexes, and coincided
with falling seawater temperatures and shorter day-lengths. The females were highly fecund, and >50 000 eggs were probably
shed from large females (>300 mm body length) during the annual spawning period. Breeding cycles of S. spallanzanii in Port Phillip Bay are ∼6 mo out of phase with endemic populations located at similar latitudes in the northern hemisphere.
The spread of S. spallanzanii within Port Phillip Bay has been monitored by divers on an annual basis since 1994. The most recent dive survey (1998) indicates
that S. spallanzanii has extended its range through out the entire 2000 km2 embayment, and has invaded most subtidal habitats. Quantitative estimates of S. spallanzanii abundances were highest on pier pylons (12.5 individuals m−2, 0.5 to 7 m depths). On sediments, estimates were highest at shallow sites (0.3 m−2, 7 m depth), but numbers declined significantly with depth (0.1 m−2, 17 to 22 m depth). Mean worm lengths and biomass were, by contrast, significantly higher at intermediate depths (12 to 17 m)
than in shallower (7 m) or deeper (22 m) locations. S. spallanzanii demonstrates a clear preference for growth in sheltered, nutrient-enriched waters, so it may not spread from Port Phillip
Bay into the adjacent oceanic waters of Bass Strait; however, in view of S. spallanzanii's current high abundance, fecundity and extended spawning periodicity, there is a high risk of future range expansions, mediated
by shipping, into other temperate-water ports.
Received: 17 November 1998 / Accepted: 6 January 2000 相似文献
20.
Late larvae of the serranid coral trout Plectropomus leopardus (Lacepède), captured in light traps, were released during the day both in open water and adjacent to two reefs, and their
behaviour was observed by divers at Lizard Island, northern Great Barrier Reef. Coral trout larvae (n = 110) were present in light-trap catches from 18 November to 3 December 1997, including new moon (30 November). The swimming
speed of larvae in open water or when swimming away from reefs was significantly greater (mean 17.9 cm s−1) than the speed of larvae swimming towards or over reefs (mean 7.2 cm s−1). Near reefs, larvae swam at average depths of 2.7 to 4.2 m, avoiding 0 to 2 m. In open water, swimming depth varied with
location: larvae >1 km east of Lizard Island swam steeply downward to >20 m in 2 to 4 min; larvae >1 km west oscillated between
2.6 and 13 m; larvae 100 to 200 m east of Lizard Island oscillated between 0.8 and 15 m. Nearly all larvae swam directionally
in open water and near reefs. In open water, the average swimming direction of all larvae was towards the island, and 80%
(4 of 5) swam directionally (p < 0.05, Rayleigh's test). Larvae swam directionally over the reef while looking for settlement sites. The frequency of behaviours
by larvae differed between two reefs of different exposure and morphology. Depending on site, 26 to 32% of larvae released
adjacent to reefs swam to open water: of these, some initially swam towards or over the reef before swimming offshore. In
some cases, offshore-swimming seemed to be due to the presence of predators, but usually no obvious cause was observed. Depending
on the reef, 49 to 64% of the larvae settled. Non-predatory reef residents aggressively approached 19% of settlers. Between
5 and 17% of the larvae were eaten while approaching the reef or attempting to settle, primarily by lizardfishes but also
by wrasses, groupers and snappers. A higher percentage of larvae settled in the second week of our study than in the first.
Average time to settlement was short (138 s ± 33 SE), but some larvae took up to 15 min to settle. Average settlement depth
was 7.5 to 9.9 m, and differed between locations. No settlement took place on reef flats or at depths <4.2 m. Larvae did not
appear to be selective about settlement substrate, but settled most frequently on live and dead hard coral. Late-stage larvae
of coral trout are capable swimmers with considerable control over speed, depth and direction. Habitat selection, avoidance
of predators and settlement seem to rely on vision.
Received: 7 July 1998 / Accepted: 26 January 1999 相似文献