bluuebunny/crossref_metadata_2025 huggingface dataset:
Vegetative and reproductive responses of charophytes to water-level fluctuations in permanent and temporary wetlands in Australia
Authors: Casanova MT
Published: November 2005

Chara australis responded to changes in water levels by altering its morphology and allocation of
resources. In a field harvest experiment, vegetative vigour of C. australis was greatest after water-level
rises and the overall morphology of the plants varied depending upon season and site of collection.
Allocation of dry weight varied over time, but allocation to sexual reproduction was always less than 10%
of the total in this dioecious perennial species. C. australis reproduced sexually through the spring, summer
and autumn, and where water levels were continually decreasing more female than male shoots were
present. Field growth rates increased when depth was increased, and sexual reproduction was stimulated
when water levels fell. An annual charophyte species (Nitella sonderi) did not display significant
vegetative or sexual responses to water-level changes. The results of these experiments show that
charophyte species can display morphological and reproductive plasticity in response to water level
changes, although as charophytes are not uniform in their adaptations to fluctuations, results from one
species cannot be extrapolated to another species. Life history could be a more important determinant of
vegetative and reproductive characteristics than is phylogenetic affinity.
Ludwigia peruviana (Onagraceae) in the Botany Wetlands near Sydney, Australia
Authors: Jacobs SWL , Perrett F , Sainty GR , Bowmer KH , Jacobs BJ
Published: November 2005

Ludwigia peruviana is an aquatic shrubby species introduced from the Americas and spreading to wetlands
in coastal south-eastem Australia. It has become dominant, replacing much of the former vegetation in the
Botany Wetlands, a series of shallow urban swamps and lakes near Sydney, Australia. Studies of
L. peruviana were essential to the development of a management plan for the Botany Wetlands. Ecological
studies were conducted in situ and supplemented by a series of germination and growth experiments in
controlled environments. Flowering peaked in early autumn. Seed production for 1990-91 was ~ 450000
seeds m-2 and there was also ~ 65000 seeds m-2 in the soil seed bank and ~ 300000 seeds m-2 in old fruits
that remained on the stems over winter. The seeds are ~ 0.8 mm long, weigh ~ 0.05 mg, are hydrophobic,
usually germinate while afloat, and are easily dispersed by water, machinery and birds. Viability of fresh
seed was 99% (tetrazolium dye test), and - 20% of seeds were dormant. Dormancy appeared to break down
within two years. Propagation and dispersal may also occur by means of stem pieces that produce new
shoots. New plants from seed, seedlings or stem fragments may become established on strand lines or form
floating islands that may eventually become stranded. Management needs to focus on control of the
seedlings and soil seed bank.
Litter accession and accumulation in a Melaleuca quinquenervia (Cav.) S.T. Blake wetland in south-eastern Queensland
Authors: Greenway M
Published: November 2005

Litterfall and litter accumulation were investigated over two years in a Melaleuca quinquenewia wetland in
south-eastern Queensland. In 1992, a seasonally wet year, litterfall was 809 � 135 g m-2 yr-1 at the
floodplain site and 764 �192 g m-2 yr-1 at the riparian site, of which Melaleuca leaf litter made up 65% and
56% respectively. Litterfall was significantly lower and more variable in 1993, a drought year, being
725�106 g m-2 and 675 � 216 g m-2 year-1. There was a distinct seasonal pattern, with peak leaf
litterfall occurring in spring in 1992 but extending into summer in 1993. Melaleuca leaf fall was
significantly lower in 1993, possibly because drought conditions caused greater leaf longevity.
Litter accumulation on the forest floor was 3457 g m-2 at the floodplain site and 2320 g m-2 at the
riparian site; there was no significant difference between years, although the organic matter content of the
litter was lower in 1992, possibly as a result of leaching during flooding. Carbon content decreased with
decreasing particle size of the litter, whereas nitrogen and phosphorus increased. There was no evidence to
suggest leaching of nitrogen or phosphorus, and the high C: N: P ratios indicate slow rates of litter decay.
The high accumulation of litter mass suggests that these woody wetlands may function as nutrient sinks.
Biomass and above-ground productivity of salt-marsh plants in south-eastern Australia
Authors: Clarke PJ , Jacoby CA
Published: November 2005

The above-ground biomass of three dominant salt-marsh vascular plants (Juncus kraussii, Sarcocornia
quinquejlora and Sporobolus virginicus) was measured to assess both spatial and temporal variation and to
provide baseline data. Additionally, the culm dynamics of the rush J. kraussii were measured so that aboveground
productivity could be estimated.
No distinct seasonal patterns were detected in above-ground biomass in J. kraussii. Averaged over all
sites and times, the above-ground biomass of J. kraussii was 1116 g dry weight m-2. Culms are replaced
annually, hence standing crop approximated annual above-ground productivity. Much of the dead aboveground
biomass appears to accumulate in the upper marsh, as evidenced by the elevated nutrient and
organic carbon content of the soil there relative to the sediment in the mangrove zone. Above-ground
biomass of the decumbent perennial grass Sporobolus virginicus and the procumbent perennial chenopod
Sarcocornia quinqueflora showed no consistent spatial or temporal trends. The above-ground standing
crops of these species were about one-third that of J. kraussii.
Sources, abundance and disappearance of polyphenolic compounds in temporary ponds of Donana National Park (south-western Spain)
Authors: Serrano L
Published: November 2005

The abundance of polyphenolic compounds in four temporary ponds in Donana National Park (south-western
Spain) was examined during three years of varying hydrology (1989-92). During flooding in 1989-90, the
ponds received large amounts of allochthonous organic matter, as indicated by the relative increases in
dissolved organic carbon (70-120 mg C L-1), dissolved polyphenolic compounds (7.6-12.2 mg L-1) and
water colour (17-33 m-1, A440). As the ponds dried out, the concentration of dissolved polyphenols
decreased rapidly in ponds with abundant submerged macrophytes, whereas the concentrations increased in
unvegetated ponds. Very low concentrations of dissolved polyphenols (1.0-2.8 mg L-1) were measured in
all ponds when they refilled again after drought in October 1991. A large percentage of the initial amount of
polyphenols (80%) and of soil organic matter (71%) disappeared from surface sediments after four months
of drought. The temporary nature of these ponds enhanced the disappearance of allochthonous organic
matter. It is suggested that sunlight and aerobic conditions promote the decrease of organic matter in pond
sediments during drought.
Observational evidence of the interaction of ocean wind-sea with swell
Authors: Reid JS
Published: November 2005

More than 10 000 spectra of ocean wave data were acquired from a series of buoys moored in the Southern Ocean off the west coast of Tasmania for a period of seven years. Spectra were grouped according to the wind speed and whether the wind direction was onshore or offshore and the mean spectrum found for each group. The frequencies of the low frequency cut-offs and of the spectral peaks of the resulting mean spectra were found to be independent of the wind speed in contrast to self-similar standard spectra such as JONSWAP. This property is attributed to the presence of a swell background which controls the evolution of wind-seas in the open ocean. During offshore winds, the spectral variance between 0.04 Hz and 0.16 Hz was found to be negatively correlated with wind speed indicating that swell is in turn shaped either by the wind-sea or by the wind itself. Relationships between various spectral and time domain parameters and the wind speed were investigated empirically. The slope/acceleration measures such as m4, the spectral fourth moment, were found to be highly correlated with wind speed.
Distribution patterns and selective feeding in two Astropecten species (Asteroidea:Echinodermata) from Cleveland Bay, northern Queensland
Authors: Lemmen s , Arnold PW , Birtles RA
Published: November 2005

During 1985, Astropecten zebra was concentrated in shallow inshore areas of Cleveland Bay, northern Queensland, Australia, whereas Astropecten velitaris was found only further offshore. The two species had an overlapping distribution in depths between 5 and 13 m, but juveniles (maximum arm length ≤ 16 mm) were virtually absent from areas of co-occurrence: A. zebra juveniles were largely restricted to inshore areas, whereas A. velitaris juveniles were predominantly found in offshore areas.
Analysis of stomach contents demonstrated that both species are selective feeders, consuming mainly bivalves and gastropods, which constituted nearly 90% of the diet in A. zebra and nearly 75% in A. velitaris. The diet of the latter is complemented largely by crustaceans (17.1%). Crustaceans were proportionately better represented in the stomach contents of A. velitaris than in bottom samples. In contrast, although foraminiferans and polychaetes dominated the bottom samples, they were virtually absent from the stomach contents of either species of Astropecten. Both species demonstrated a preference for small prey items. Although spatial differences in the diet of A. velitaris were observed, there was little evidence for competitive interactions.
The findings strengthen the view that there is a clear horizontal zonation in benthic communities of the Great Barrier Reef Marine Park, requiring an appropriate management strategy.
The coral communities of Lord Howe Island
Authors: Harriott VJ , Harrison PL , Banks SA
Published: November 2005

Lord Howe Island (31�33′S, 159�05′E) is surrounded by the southern-most coral reefs in the Pacific Ocean. The status of the benthic communities at Lord Howe Island was quantified in 1992-93 using replicated video-transects at 20 sites in the shallow reefal area (<20 m depth). The cover of hard coral was comparable with coral cover on some tropical reefs, ranging from less than 10% at some reef flat sites to greater than 40% cover at two seaward beach sites. The process of reef formation is apparently slow, and accretion of limestone is localized. A total of 59 scleractinian coral species were recorded during this study (including 19 new records), bringing the total number recorded at Lord Howe Island to 83. The coral communities contain a unique association of tropical species at their southern limits of distribution, and subtropical species which are rare or absent from the Great Barrier Reef. Many of the species that have been recorded from Lord Howe Island are rare, and may have resulted from chance recruitment of only a few larvae. There have been few major changes in the coral communities at Lord Howe Island in the past 16 years. At two inshore sites there was an apparent reduction in hard coral cover in the 1980s.
Reproduction of Euastacus bispinosus Clark (Decapoda:Parastacidae), and trends in the reproductive characteristics of freshwater crayfish
Authors: Honan JA , Mitchell BD
Published: November 2005

The reproductive biology of Euastacus bispinosus populations was studied in a river and a creek of the Glenelg River system in south-western Victoria, and a small coastal creek in south-eastern South Australia.
Females produced eggs in the first breeding season after maturation of their gonopores. At the Victorian sites, E. bispinosus spawned in early May, carrying eggs for about seven months before hatching and juvenile release in October-December. At least 95% of mature females at each Victorian site carried eggs during the breeding season. Mature females had relatively broader abdomens than did males and carried between 63 and 812 eggs. The number of eggs carried was linearly related to both occipital carapace length and abdomen width.
The South Australian population differed from the Victorian populations in having a smaller mean size at sexual maturity for females (occipital carapace length 58 mm compared with 85-86 mm in Victoria), a higher proportion (17%) of gonopore abnormalities (< 1% in Victoria), and relatively wider abdomens (which continued to broaden after maturity).
Euastacus bispinosus is a winter brooder and has a long generation time and low potential reproductive rate, characteristics it shares with Astacopsis and Parastacoides species, and members of the Astacidae. Other crayfish species (e.g. Cherax species and members of the Cambaridae) are summer brooders and tend to have a high potential reproductive rate and short generation time.
Larval dispersal and recruitment of Haliotis discus hannai and Tegula spp. on Miyagi coasts, Japan
Authors: Sasaki R , Shepherd SA
Published: November 2005

The spatial dispersal and vertical distribution of larvae of Haliotis discus hannai and Tegula spp. were examined in relation to storm events in Miyagi Prefecture, Japan, from 1983 to 1993. Epidemic spawning is induced by typhoons and minor storms. After typhoons, larvae are dispersed in coastal waters up to 3 km from shore to a depth of 30 m and later are advected toward the coast by onshore winds. After minor storms, larvae are locally dispersed close to shore. Larvae of H. discus hannai and Tegula spp. become vertically stratified and settle on the substratum at depths in accordance with the vertical depth range of their larvae. Strong settlements of H. discus hannai of up to 200 m-2 were recorded around headlands, with average survival rates of about 13% per month in the first 2-3 months. The adaptive significance of dispersal over short and long distances is considered.
Measuring settlement intensity of abalone: Results of a pilot study
Authors: Keesing JK , Grove-Jones R , Tagg P
Published: November 2005

Results of a pilot study to assess the utility of settlement collectors for measuring settlement intensity of abalone in the field are presented. The collectors, consisting of transparent PVC sheeting, were conditioned in sea water before being deployed on the seabed in habitat containing adult and juvenile abalone. Collectors were recovered and replaced at intervals of between one and eight weeks over a 12-month period. The optimum period was found to be between two and four weeks. Two discrete peaks in settlement were recorded, coinciding with the annual spawning activity of two species, Haliotis rubra and Haliotis laevigata. Intensity of settlement in each peak was equivalent to 114 m-2 and 45 m2 respectively.
Growth of the ass's ear abalone (Haliotis asinina Linné) on Heron Reef, tropical eastern Australia
Authors: McNamara DC , Johnson CR
Published: November 2005

Growth of ass's ear abalone (Haliotis asinina) was measured in situ (mark-recapture of adults) and in aquaria (juveniles) on Heron Reef, Queensland. A growth curve (y = 4.27L2.03 e-u, where y is the growth rate, L is the shell length, and u = 0.27L0.88) fitted to these data indicated a sigmoidal age-length relationship. It is estimated that H. asinina may grow from 2 mm to 35.6 mm in shell length in six months and 55.0 mm in one year. These growth estimates are consistent with temporal shifts in the size-frequency distributions of juveniles in the field. Peak growth rates, estimated at over 120 mm year-1 in young abalone (approximately 3-4 months of age), are the highest recorded for any abalone species.
Shell growth checks and growth of the Omani Abalone Haliotis mariae
Authors: Shepherd SA , Al-Wahaibi D , Al-Azri AR
Published: November 2005

Settlement of the Omani abalone Haliotis mariae Wood on the Dhofari coast in 1992 occurred from January until April. Growth was measured by analysis of modal progressions of cohorts in length-frequency data, mark-recapture data and frequency of primary growth checks. The annual increase in shell length was about 43 mm in the first year and 20-25 mm in the second and third years. Primary and secondary growth checks in the shell were caused by spawning and seasonal factors. Parameters of fitted von Bertalanffy growth curves were K = 0.27-0.43 per year and L∞ = 139 to 149 mm according to site. Examination of the rate of deposition of rings in the spire indicated that four rings per year were laid down, but that one ring per year was lost through erosion of the shell.
Growth and movement of the South African abalone Haliotis midae: A reassessment
Authors: Tarr RJQ
Published: November 2005

Growth rates of a number of Haliotis midae populations around the South African coast were studied by means of tagging. These populations ranged from the cool waters of the western coast to the more temperate environment of the eastern Cape. Standard von Bertalanffy growth curves were fitted and growth parameters derived. These ranged from 0.19 to 0.25 for K, the average rate at which L∞ is approached, and from 156 to 173 for L∞, the average theoretical maximum length. These indicate far higher growth rates than were previously published for this commercially fished species, and the reasons for this difference are discussed. The expectation that growth rates would be fastest in the warmer eastern Cape waters was not realized, there being no significant difference in growth between the Bird Island population on the eastern coast and the Robben Island population on the western coast. These new growth parameters indicate that H. midae in the commercial fishery grounds is attaining sexual maturity some four years earlier, and the minimum legal size some five years earlier, than previously considered. This has considerable significance for modelling studies presently underway.
Movement of a small population of adult H. midae was studied over a three-year period, after which 47% of the original abalone were still present on the study site. Of these, 81.5% still occupied exactly the same position on the rocks. This indicates that H. midae that have located an optimum habitat, and that are not disturbed, tend not to move.
A comparison of fluorochromes for marking abalone shells
Authors: Day RW , Williams MC , Hawkes GP
Published: November 2005

This study assessed the potential of five fluorochromes in marking shells of the abalone Haliotis rubra, using an immersion technique. Such marks are required to 'time stamp' the shells and thus determine whether shell layers are deposited regularly enough to be used to age abalone. The stains used were: oxytetracycline and tetracycline at 300-1000 mg L-1; calcein at 10-120 mg L-1; alizarin red S at 10-60 mg L-1; and xylenol orange at 20-100 mg L-1. Immersion times were 12, 24 and 48 h. Mortality rates were low in all treatments, and clearly discernible marks were produced when abalone were immersed for 24 and 48 h at high concentrations in all the stains. Three problems were encountered when tetracyclines were employed: (i) the solutions were acidic, so the pH had to be adjusted with NaOH to prevent mortality; (ii) there was excessive foaming of the solutions; and (iii) a natural fluorescence in the shells closely resembled that of the tetracyclines. Problems also arose in assessing alizarin red and xylenol orange because they have long emission wavelengths, so that simultaneously viewing natural layers on the sections is difficult. Calcein, although expensive, was the most effective, as at high concentrations it consistently produced bright, extensive marks. The success of marking appeared to depend on the growth rate of the abalone, as feeding before staining increased the intensity of marks, and marking varied between batches of abalone collected at different times.
Toward a chronology of Haliotis fulgens, with a review of abalone shell microstructure
Authors: Shepherd SA , Avalos-Borja M , Quintanilla MO
Published: November 2005

The microstructure of the shell of the abalone Haliotis fulgens consists of alternate layers of aragonite and prismatic calcium with darker organic matrix (conchiolin) that are visible as rings when the shell is ground down at the spire. This abalone deposits about four prismatic layers in the first year and three layers each year thereafter at the site studied. Prismatic layers are laid down in about April, August and November, corresponding with sea temperature minima and maxima and with the spawning season. After about 3 years of age, prismatic layers at the spire of the shell begin to be lost through erosion of the outer layers of the shell. The first prismatic layers deposited are 5-10 �m across, and later layers successively increase in thickness to a maximum of about 80 �m. This property is used to estimate the rate of erosion of layers, which is about one per annum. When the rate of deposition and the rate of erosion are known for a locality, an estimate of the true age can be made. The findings are considered in relation to the microstructure of the abalone shell.
Reproduction of paua, Haliotis iris Gmelin 1791 (Mollusca:Gastropoda), in north-eastern New Zealand
Authors: Hooker SH , Creese RG
Published: November 2005

An examination of the reproductive condition of a population of paua, H. iris, at Leigh in north-eastern New Zealand during 1986-87 revealed a long breeding season extending from late summer through autumn and winter and into early spring. Within this period, a sharp decrease of over 60% in the gonad index for both males and females indicated major spawning events in July and October. A smaller decrease in the gonad index in March suggested a third, minor spawning. These spawning events were confirmed by regular examination of histological sections of gonadal material. This breeding pattern is different from that previously described for southern localities in New Zealand, where spawning activity is limited to a four-month period from late summer into autumn. Paua in this northern population had a sex ratio slightly biased towards males (1 female to every 1.3 males) and achieved reproductive maturity between the sizes of 48 and 60 mm shell length. These features are also different from those described for southern populations of H. iris. These findings highlight the need to take regional differences in reproductive pattern into account when describing the population dynamics of marine gastropods.
Bias towards brown algae in determining diet and food preferences: The South African abalone Haliotis midae
Authors: Day RW , Cook P
Published: November 2005

Previous studies of gut contents have suggested that Haliotis midae in South Africa feeds selectively on brown algae, and that the feeding preferences of this abalone might differ from other species in favouring tannin-rich foods in accord with an evolutionary hypothesis based on food availability. In the present study, H. midae specimens were starved for one month, then fed a variety of algae and frozen at intervals thereafter, to assess whether gut contents provide a good estimate of diets. Fragments of the brown kelps Ecklonia maxima and Laminaria pallida disappeared more slowly than did green or red algae from the abalone crop, as expected from work on H. rubra in Australia and the fact that the kelps contain high concentrations of phlorotannins. The apparent extent to which H. midae feeds on E. maxima, derived from gut content analysis, is biased. There is thus no good evidence that any abalone, faced with brown algae rich in polyphenolics, have adapted to select these foods.
Yield-per-recruit and egg-per-recruit analyses of the Omani abalone, Haliotis mariae
Authors: Shepherd SA , Baker JL , Johnson DW
Published: November 2005

The fecundity, size at sexual maturity, sex ratios and total mortality of Haliotis mariae on the Dhofar coast of the northern Arabian Sea were measured. These data, and estimates of the growth rate, were used for yield-per-recruit and egg-per-recruit analyses. Maximum yields occur at 3+ to 4+ years of age, depending on the natural mortality rate chosen. At the present age at first capture egg production levels are 2-29% of the unfished stock, depending on estimates of the fishing mortality rate and the natural mortality rate, and are considered to be far too low to maintain recruitment. At 40% egg production, of the maximum possible the age at first capture is 4 to 4.5 years, i.e. 105-115 mm shell length, depending on site.
Development and depth distribution of the eggs of orange roughy, Hoplostethus atlanticus (Pisces: Trachichthyidae)
Authors: Bulman CM , Koslow JA
Published: November 2005

The development of the eggs of deep-sea fish has seldom been described. The eggs of orange roughy (Hoplostethus atlanticus), a mid-slope benthopelagic fish, were fertilized and incubated at three temperatures. Those incubated at 7�C hatched at 13 days; wild eggs were estimated to hatch at 7.3 days. Their development rate was similar to that of eggs of fish from other orders and of shallower- living species. From depth-stratified plankton samples, early-stage eggs were found at 500-700 m. Their buoyancy was estimated to be 6.02 kg m-3, the upper end of the range of known fish-egg buoyancies. The eggs rose to the upper mixed layer at an estimated 23.8 m h-1, which is faster than ascent rates reported for other fishes. Their relative buoyancy and large size would be the reason for this faster rate. However, large egg size is apparently not an adaptation to enhance development rate; the more rapid rise into warmer water reduces development time but does not fully compensate for the slower development.
Cross-shelf distribution patterns of tropical juvenile cephalopods sampled with light-traps
Authors: Moltschaniwskyj NA , Doherty PJ
Published: November 2005

This paper describes the cephalopod genera caught with light-traps at different locations and depths in the waters of the central Great Barrier Reef (GBR). Multiple stations were sampled in four locations: (I) the coastal GBR Lagoon, (2) inter-reef passages (Magnetic and Palm), (3) near-reef environments (Keeper, Helix, Faraday and Myrmidon) ranging from mid- to outer-shelf locations, and (4) the Coral Sea. A total of 13 cephalopod genera was caught from monthly cruises conducted from October to January of 1990-91 and 1991-92. Octopus, the most abundant juvenile cephalopod, was present in relatively high numbers at all shelf locations; few were caught in the Coral Sea. Photololigo, the most abundant squid, was rarely caught outside the GBR Lagoon. In contrast, Sthenoteuthis, the second most abundant squid, was caught at all locations. Deep samples from most locations were dominated by Octopus. Abralia was found only near the bottom of the GBR Lagoon; in contrast, Euprymna, the fourth most abundant genus, was collected only at the surface. Cephalopod communities from the GBR Lagoon had higher abundances of Octopus, Photololigo and Abralia compared with communities from the three other areas. Reef passages and reef locations shared similar communities, with the squid component dominated by Sthenoteuthis. Very low numbers of cephalopods were caught in the Coral Sea by light attraction. High concentrations of cephalopods detected in the middle of the GBR Lagoon are consistent with present knowledge about oceanographic processes over this shelf.
Aspects of the reproductive cycle and gonadal development of Murray cod, Maccullochella peelii peelii (Mitchell) (Percicthidae), in Lake Charlegrark and adjacent farm ponds, Victoria, Australia
Authors: Gooley GJ , Anderson TA , Appleford P
Published: November 2005

The gonadal development of Murray cod, Maccullochella peelii peelii, in Lake Charlegrark, Victoria, and adjacent farm ponds was evaluated. Gonadosomatic index, macroscopic classification and histological analysis were used to determine the age at first maturity and the gonadal development in this introduced population.
There is a marked difference between the sexes in the size at first maturity, with females maturing at approximately 6 years of age and 2000 g in weight and males maturing at 3-4 years and 700 g. Gonadosomatic index data indicate that spawning occurs around November.
Ovarian development in this species follows a pattern similar to that in a number of other teleosts. Testes have a lobular structure. Macroscopic evaluation of ovaries provided a good indication of the stage of the development of the gonad. However, the presence of spermatozoa throughout the year in the gonads of mature male fish makes the macroscopic evaluation of testicular development less reliable.
Three cod, approximately 1% of the population, contained gonads with both ovarian and testicular tissue.
Egg and larval abundance and spawning localities of the anchovy (Engraulis australis) and pilchard (Sardinops neopilchardus) near Phillip Island, Victoria
Authors: Hoedt FE , Dimmlich WF
Published: November 2005

The distribution and abundance of the eggs and larvae of the anchovy (Engraulis australis) and pilchard (Sardinops neopilchardus) were determined for the waters near Phillip Island between May 1992 and January 1994. Eggs and larvae of both species were common in these waters, indicating that this region is an important spawning area for both species. Pilchard eggs and larvae occurred at sample stations in Bass Strait and in the western entrance to Western Port. Anchovy eggs and larvae were collected both within Western Port and at most plankton stations in Bass Strait. The mean density of anchovy eggs in Western Port differed markedly between the two spawning seasons, suggesting that the number of adult fish spawning therein can vary between years. Densities of pilchard eggs and of the larvae of both species exhibited considerable spatial variability in Bass Strait.
Effects of an increase in mesh size on the catches of fish trawls off New South Wales, Australia
Authors: Broadhurst MK , Kennelly SJ
Published: November 2005

In response to claims that fish trawls off New South Wales, Australia, caught excessive quantities of under-size fish, the catches of finfish by a conventional fish trawl (constructed of 90-mm mesh in the body) were compared with those by a fish trawl constructed of 100-mm mesh in the body. Catches by the 100-mm trawl showed a 27% reduction in all by-catch and a 28% reduction in the numbers of retained tiger flathead, compared with catches by the conventional trawl. The 100-mm trawl also showed a 48% and 47% reduction in the numbers and weights respectively of discarded tiger flathead and a 57% and 63% reduction in the numbers and weights respectively of discarded rubberlip morwong. For john dory, however, at a particular locality where large numbers occurred, the 100-mm trawl caught significantly more fish than did the conventional trawl (a mean increase in weight of 66%). There is a need to determine species-specific mesh selectivities and to study the behaviour of fish in trawls. The importance of the results for the future management and operational efficiency of trawl fisheries is discussed.
Genetic and morphological differences between populations of the western minnow, Galaxias occidentalis, from two river systems in south-western Australia
Authors: Watts RJ , Storey AW , Hebbert DR , Edward DHD
Published: November 2005

Allozyme electrophoresis was used to examine patterns of genetic differentiation in the western minnow, Galaxias occidentalis, from the North Dandalup and Canning Rivers in south-westem Australia. Two distinct genetic forms of this species were identified in these rivers and both forms occur sympatrically in samples from two sites. A significant deficit of heterozygotes and a non-random association of alleles among loci was observed in these two samples. The distribution of one of the genetic forms extended from the headwater streams in the Darling Range to the transition zone between the ranges and the Swan Coastal Plain. With the exception of one population, the distribution of the other form extended from the transition zone to the Swan Coastal Plain. The exception was a population that was caught from a site in the ranges but grouped with the populations from the coastal plain. Discriminant analyses of meristic and morphological data were undertaken to determine if morphological differences exist between the two identified genetic groups. All individuals were correctly classified by the analyses of samples from each catchment separately and of the two sympatric populations separately. However, the discriminant analysis of individuals from all sites correctly classified only 85.7% of the Darling Range genetic group and 79.4% of the Swan Coastal Plain genetic group. Further research is required to clarify the taxonomic status of these two genetic forms of G. occidentalis.
Associations between sea temperature, catch per unit of fishing effort, and yield in the Bermuda spiny lobster fishery, 1975-1989
Authors: Evans CR , Lockwood APM , Evans AJ
Published: November 2005

Results of graphical analyses of annual records of catch, effort and sea temperature indicate empirical quadratic associations between industry catch per unit of fishing effort (CPUE) in Bermudan spiny lobster (Panulirus argus and P. guttatus) fisheries and the annual average sea temperature at Hamilton Harbour, Bermuda. CPUE and yield of P. argus and of P. guttatus were each associated by quadratic expressions with the annual average sea temperature of the Bermuda Platform. Annual growth and survival of late juvenile P. argus and P. guttatus into the fishable stock at Bermuda is controlled in a quadratic fashion chiefly by sea temperature with a six-month lag. The optimum annual average sea temperature for the survival and growth of late benthic juvenile P. argus into the fishery stock was 23.6 � 0.2�C (mean � s.e.), and the comparable optimum for P. guttatus juvenile recruitment was 24.1 � 0.1�C. The maximum equilibrium catch of P. guttatus lobsters on Bermuda Platform was estimated at approximately 33 000 lobsters from quadratic regression of yield on fishing effort.
Temporal and spatial patterns of spawning in jack mackerel, Trachurus declivis (Pisces:Carangidae), during 1988-91 in eastern Tasmanian waters
Authors: Jordan A , Pullen G , Marshall J , Williams H
Published: November 2005

Ichthyoplankton surveys conducted during the summer and autumn of 1988-89, 1989-90 and 1990-91 along the eastern coast of Tasmania were used to examine the spatial and temporal patterns of eggs and larvae of jack mackerel, Trachurus declivis. Results indicate that the species spawns along the entire eastern coast during summer. Trachurus declivis eggs were most abundant at shelf-break stations, indicating that spawning is concentrated in this region, although high concentrations of eggs were present on the inner shelf in 1988-89, which can be attributed to rapid onshore transport in that year. Larvae were evenly dispersed over the shelf, with the distribution of larval ages showing no indication of inshore recruitment. Considerable interannual differences in sea surface temperatures and vertical thermal structure were apparent, with the warmer waters and strong thermal stratification in the summer of 1988-89 resulting from the influx of subtropical East Australian Current (EAC) water onto the shelf, which corresponded with a major La Nina 'cold event' at that time. It is suggested that the distribution of spawning is unaffected by the interannual variations in oceanography as the mature population spawns in deeper water in the shelf-break region that is unaffected by the warming in surface waters.
Short- and long-term movement patterns of six temperate reef fishes (Families Labridae and Monacanthidae)
Authors: Barrett NS
Published: November 2005

Movement patterns were studied on a 1-ha isolated reef surrounding Arch Rock in southern Tasmania. Short-term movements were identified from diver observations, and interpretation of long-term movements involved multiple recaptures of tagged individuals. Visual observations indicated that the sex-changing labrids Notolabrus tetricus, Pictilabrus laticlavius and Pseudolabrus psittaculus were all site-attached, with females having overlapping home ranges and males being territorial. In the non-sex-changing labrid Notolabrus fucicola and in the monacanthids Penicipelta vittiger and Meuschenia australis, there was no evidence of territorial behaviour and 1-h movements were in excess of the scale of the study. The long-term results indicated that all species were permanent reef residents, with most individuals of all species except M. australis always being recaptured within a home range of 100 m × 25 m or less. Only 15% of individuals of M. australis were always recaptured within this range category. The natural habitat boundary of open sand between the Arch Rock reef and adjacent reefs appeared to be an effective deterrent to emigration. The use of natural boundaries should be an important consideration in the design of marine reserves where the aim is to minimize the loss of protected species to adjacent fished areas.
Condition index and chemical composition of meats of Sydney rock oysters (Saccostrea commercialis) and Pacific oysters (Crassostrea gigas) at four sites in Port Stephens, NSW
Authors: Mason CJ , Nell JA
Published: November 2005

Adult Sydney rock oysters (Saccostrea commercialis) and Pacific oysters (Crassostrea gigas) were kept on commercial oyster leases at three intertidal sites in Port Stephens, New South Wales, and subtidally under an experimental raft at a fourth site between July 1988 and September 1989. Oysters were sampled from each site at approximately monthly intervals for chemical and histological analysis. Condition index and percentage glycogen of Pacific oysters were higher than those of Sydney rock oysters during winter and spring but tended to be lower during summer and autumn. Gonads of Pacific oysters matured two months earlier than those of Sydney rock oysters, with spawning being observed at all sites in October. Sydney rock oysters spawned later during December-January and did not lose as much condition after spawning as Pacific oysters.
The absolute amount of glycogen in the meats of both species dropped at the expense of protein and lipid as the oysters became fully ripe. For both species, general condition of the oysters was best when they were grown subtidally under the raft, although both species were badly affected by invasion of the protistan parasite Mikrocytos roughleyi at this site. Poorest overall condition for both species occurred at a site (Karuah River) that experienced decreased salinities and increased turbidity after rain. Highest condition indices were found in Sydney rock oysters, at the site most dominated by coastal conditions (Corrie Island).
Comparison of methods for sampling ectoparasites from coral reef fishes
Authors: Grutter AS
Published: November 2005

Methods for sampling ectoparasite assemblages were compared using 7 species of coral reef fishes (Acanthochromis polyacanthus, Thalassoma lunare, Ctenochaetus striatus, Chlorurus sordidus, Scolopsis bilineatus, Hemigymnus melapterus, and Siganus doliatus). Estimates of total numbers and composition of ectoparasites were dependent on post-collection handling techniques and the method of ectoparasite removal. Fish were enclosed within plastic bags under water at the point of capture. Filtration of water from the plastic bags revealed a large number of parasites (mainly gnathiid isopods) that had detached from the host on capture. A subsequent sea-water rinse removed a large number of ectoparasites, but further treatment with the anaesthetic chloretone released additional individuals. The few remaining parasites were removed by visual inspection. A chloretone bath was more effective than a sea-water bath at removing parasites. The species composition of parasites recovered by a chloretone bath plus a visual survey was different from that recovered with a sea-water bath and visual survey; this suggests that traditional scanning techniques may not detect all parasites.
Factors affecting distribution and abundance of small demersal fishes in the Gulf of Carpentaria, Australia
Authors: Martin TJ , Brewer DT , Blaber SJM
Published: November 2005

The distribution and abundance of small demersal fishes at depths of 7 to 63 m in the Gulf of Carpentaria were surveyed at 103 stations in 1990 and 60 stations in 1991 with the aid of a Church dredge. A total of 234 species from 70 families was recorded. The most abundant fish groups were cryptic or benthic species such as pleuronectiforms, scorpaenids, apogonids, platycephalids, monacanthids and gobiids. Several species, such as Elates ransonnetti, Pseudorhombus elevatus and Suggrundus macracanthus, are widely distributed; others had a narrower distribution. Apogon poecilopterus, Apogon fasciatus, Arnoglossus waitei and Uranoscopus cognatus were most abundant in the northern Gulf of Carpentaria and Cynoglossus macrophthalmus, Dactyloptena papilio and Paramonacanthus japonicus in the eastern gulf. The dredge is more efficient at catching smaller fish: the smallest individuals of 113 species were caught by the dredge and a further 32 small species were caught only by the dredge. The effects of depth, substratum type and turbidity on the abundance of 17 common species at different stations are described. Neither temperature nor salinity showed significant correlations with catches of the common species. There were significant correlations between the presence of structured benthos and both the number of fish species and the number of fish individuals. The relationship between benthic structure and fish is discussed in relation to the possible effects of trawling, and it is postulated that changes to structure resulting from trawling may affect fish community composition.
Allozyme and mitochondrial DNA separation of Pacific northern bluefin tuna, Thunnus thynnus orientalis (Temminck and Schlegel), from southern bluefin tuna, Thunnus maccoyii (Castelnau)
Authors: Ward RD , Elliott NG , Grewe PM
Published: November 2005

Northern and southern bluefin tunas are morphologically similar and can be misidentified, posing problems for fishery management and marketing. Allozyme variation and restriction-site variation in mitochondrial DNA (mtDNA) were used to distinguish between the two species. A survey of 36 allozyme loci active in white muscle and liver tissue showed that the genetic identity between the species was high (Nei's I = 0.907). One diagnostic locus (sAH*) and two nearly diagnostic loci (ADA* and GDA*) were found, and four loci showed highly significant allele frequency differences (FH*, GPI-A*, PGDH* and sSOD*). A survey of the mtDNA genome, using 15 restriction enzymes and southern blotting, revealed five restriction enzymes that gave species-diagnostic restriction digest profiles (Ban I, Bcl I, Dra I, Pvu II, Xba I) and a further three enzymes (Pst I, Barn HI and Nco I) with large haplotype frequency differences. Mitochondrial DNA analysis provided more reliable discrimination of specimens than did allozyme analysis, although the more rapid allozyme identification will be accurate for most specimens. The two biochemical genetic methods were then used to identify Australian-caught fish of uncertain identity. Six of 12 tuna originally considered to be northern bluefin tuna were confirmed as northern bluefin and six were identified as southern bluefin. The presence of northern bluefin tuna as far south as south-western Tasmania was confirmed.
Reproductive parameters of blue shark, Prionace glauca, and other sharks in the Gulf of Guinea
Authors: Castro JA , Mejuto J
Published: November 2005

In total, 1967 pelagic sharks of eight different species were sampled in waters of the Gulf of Guinea between June and August 1993 by commercial longline gear. Catches of Prionace glauca and Sphyma zygaena included a large number of pregnant females, making it possible to calculate some of their reproductive parameters.
In total, 419 gravid females of P. glauca were caught, ranging in size from 170 to 260 cm fork length. The size at which 50% of females have embryos was determined to be 180 cm FL. Examination of the uteri from 128 of these females showed a higher number of embryos (59-60%) in the right uterus. The mean number of embryos was 37. Data on embryo size suggests that P. glauca may have a west-east migration to give birth along the Atlantic equatorial line. The embryonic sex ratio was 1 : 1.
In the same catch there were 21 gravid females of S. zygaena. No difference in the number of embryos between uteri was found in this species. Mean embryo number was 33.5 and embryonic sex ratio was 1 : 1.
Tissue nutrient content of Gracilaria spp. (Rhodophyta) and water quality along an estuarine gradient
Authors: Horrocks JL , Stewart GR , Dennison WC
Published: November 2005

Tissue nutrient content of Gracilaria spp. (Rhodophyta) was tested as a bioindicator of water column nutrient availability in the Logan River and southern Moreton Bay, south-eastem Queensland. Macroalgae were incubated for one to two weeks within flow-through incubation chambers suspended in the water column. Tissue nutrient content of Gracilaria spp, and water column nutrients were measured at five sites over a five-month period. Tissue nitrogen content (%N) was correlated with dissolved inorganic nitrogen (DIN) at a site 15 km upstream from the Logan River mouth (r² = 0.81), at the Logan River mouth (r² = 0.50), and at a Moreton Bay site 8 km from the Logan River mouth (r² = 0.71). Time-course analyses of water column nutrients and plant tissue content showed more significant correlations with nitrogen (N) than with phosphorus (P). Plant tissue nitrogen-to-phosphorus (N:P) molar ratios ranged between 19 and 23 whereas water column N:P ratios were between 2 and 6, suggesting low nitrogen availability relative to plant requirements and possible N limitation.
In the laboratory, Gracilaria verrucosa was subjected to treatments of N, P or N + P nutrient additions. Deepening of the thallus colouration was observed after additions of N. Chlorophyll and phycoerythrin concentrations increased in treatments with N addition; however, owing to wide variability between phycoerythrin replicates, only chlorophyll increases were significant. The amino acid citrulline also increased with the addition of N and accounted for up to 16% of the total tissue N. Macroalgae may be more useful than traditional water quality sampling for integrating biologically available pulses of nutrients, especially for a limiting nutrient such as N in coastal marine ecosystems.
Effects of feeding by Agapetus species (Trichoptera) on the density of epilithon in an Australian upland stream
Authors: Gawne B
Published: November 2005

The effects of feeding by an abundant glossosomatid trichopteran on the density of epilithon on cobbles in an upland stream were evaluated by using both exclosures and flow-through in-stream channels. The in-stream channel experiment found that Agapetus kimminsi Banks had the ability to reduce significantly the density of epilithon on experimental substrata and that this effect was more pronounced on the sides of experimental substrata. The exclosure experiment found that excluding Agapetus monticolus Banks from experimental substrata within the stream had no effect on epilithon density. The different results from the two experiments appear to be due to the use of different experimental protocols and indicate that although Agapetus species are capable of affecting the density of epilithon, they may have only a limited effect within the stream. The limited effect of Agapetus species on the density of epilithon may be due to the effects of other environmental factors (e.g. current) both on the foraging activities of Agapetus species and on the density of epilithon.