bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth and demography of the Pacific Angle Shark (Squatina californica), based upon tag returns off California
Authors: Cailliet GM , Mollet HF , Pittenger GG , Bedford D , Natanson LJ
Published: November 2005

Knowledge of the age, growth and demography of an organism can be quite useful for managing its fishery. However, for many elasmobranch species, no valid estimates of age, growth and therefore age-specific mortality and natality rates are available. Thus, even though the distribution, abundance, habits and reproduction of a population may be known, no reliable estimates of population growth are possible. As a result, detailed demographic analysis has been completed for only a few shark species (e.g. the California leopard shark, Triakis semlfasciata). All age-determination techniques attempted for the Pacific angel shark (Squatina californica) have met with difficulties. Recently, however, we have accumulated data on 69 tag-recaptures and have used this information to model a von Bertalanffy growth function (VBGF) to predict the growth of this commercially exploited shark species. We performed a demographic analysis of this species, which yielded a net reproductive rate (R0) of 2.25, a generation time (G) of 14.5 years, and an estimate of the instantaneous population growth coefficient (r) of 0.056 year-1, assuming that only natural mortality (M) was occurring, estimated to be 0.2 year-1. When reasonable estimates of fishing mortality (F) are included in the survivorship function, Ro and r are reduced considerably. Presently, Pacific angel sharks first enter the fishery at the same size and age at which they first reproduce. Until accurate estimates of M and Fare available, it would be prudent to set a size limit considerably above the size at first reproduction to protect the Pacific angel shark in California.
Modelling of the residual circulation in Broken Bay and the lower Hawkesbury River, NSW
Authors: Kjerfve B , Seim HE , Blumberg AF , Wright LD
Published: November 2005

To elucidate the importance of lateral circulation in estuaries, a tidal circulation model was applied to Broken Bay and the lower Hawkesbury River estuarine system in New South Wales, Australia. The numerical simulation model solves the vertically averaged governing equations explicitly on a 61 × 51 finite difference grid, utilizing a 6.5-s computational step. The model is forced with an M2 tidal wave with a 1.1-m range, steady homogeneous wind stress, and river discharge. The time-averaged circulation is computed as residual transport velocities and consists of a series of residual circulation gyres. These gyres are due to tidal ebb-flood flow asymmetries and suggest the importance of lateral estuarine circulation. Very limited field data are consistent with this interpretation. Gyres in open areas change their sense of rotation in response to changing wind stress, whereas the gyres in the main channel appear to be independent of wind stress. With river discharge increased from 38 to 1250 m3 s-1, the gyres are replaced by strong ocean-directed residual velocities. The residual Stokes' drift is everywhere landward-directed and is weak except in shallow, constricted areas.
Fish assemblages in residential canal developments near the mouth of a subtropical Queensland estuary
Authors: Morton RM
Published: November 2005

The hydrological conditions and fish fauna occurring in canal developments situated near the mouth of a subtropical estuary in southern Queensland were studied for 15 months from December 1985 to February 1987. In contrast to canal developments situated in bays or the middle reaches of estuaries, these downstream canals did not entrap sediments, and only minimal silt deposition occurred in those canals most isolated from the river. Hydrological conditions within the canals were generally within recommended limits for fish survival, although low oxygen concentrations in bottom water occurred on isolated occasions in the dead-end canals. The ichthyofauna of these canals, as in other canal developments, was dominated by planktivores/microcarnivores of no direct importance to fisheries. These fish guilds occurred in substantially greater numerical proportions in the canals than in undisturbed wetland areas. Well-flushed canals constructed in nontidal sandy areas are likely to have minimal impact on existing fish communities and could increase the area of available fish habitat. Extra keywords: canal design, hydrology, oxygen content, estuarine fisheries, coastal development.
Dissolved trace metal speciation in the Manuherikia River, Central Otago, New Zealand
Authors: Hawke DJ , Hunter KA
Published: November 2005

The inorganic speciation of the trace metals Cu, Ni, Cd, Zn and Pb has been calculated for the pristine, subalpine Manuherikia River. Temperature, pH, ionic strength and major-ion composition were found to be important controls on the free-ion activity of trace metals. Metal -CO3-2 species were the most important complexes for Pb, Cu and Ni. The metal-HCO3- species was most important for Cd, and Zn was intermediate. Ni, Zn and Cd were present mainly as the free divalent ion, whereas Pb (up to 81% complexed) and Cu (up to 70% complexed) were strongly affected by ionic interactions. Free-ion activities of Cu2+ and Pb2+ were essentially constant along the length of the river despite significant increases in total dissolved-metal concentrations. Thus, for these metal ions, total dissolved concentrations are a poor indicator of biological availability.
Total mercury concentrations in sand flathead, Platycephalus bassensis Cuvier & Valenciennes, from Port Phillip Bay, Victoria
Authors: Fabris GJ , Monahan C , Nicholson G , Walker TI
Published: November 2005

Total mercury concentrations were measured in the axial muscle tissues of 562 sand flathead (Platycephalus bassensis) from a total of 37 sites within Port Phillip Bay, Victoria. Mean concentrations of mercury (0.23 �0.18�g g-1 wet weight) were less than half (P<0.05) of those recorded for this species during 1975-78 and below the Victorian health standard for fish and fish products (i.e. less than a mean concentration of 0.5 �g g-1 wet weight) at all 37 sites. During the 1975-78 period, mercury concentrations in sand flathead from the bay were reported to decrease from north to south and from east to west. During 1990, however, mercury concentrations were found to be related to the water depth at which the fish were sampled. Sand flathead from the deeper (22 m) waters of the bay had significantly (P<0.05) higher mean mercury concentrations than did those collected from shallower (7 m) waters. The overall mean mercury concentration in sand flathead from the bay during 1990 approached the mean concentration in sand flathead collected from six sites in Bass Strait (0.22 �g g-1) during 1975-78, although the range of concentrations for the Port Phillip Bay samples (0.01- 0.89 �g g-1) was wider than that for the Bass Strait samples (0.1-0.33 �g g-1).
Abundance and distribution of the black-lip pearl oyster, Pinctada margaritifera (L.), in the Cook Islands, South Pacific
Authors: Sims NA
Published: November 2005

Stocks of Pinctada margaritifera were surveyed in three atoll lagoons in the Cook Islands to assess abundance, describe distribution patterns, and evaluate the method for ongoing monitoring. Belt transects were laid at randomly selected sites across the lagoons. Densities over depth gradients were extrapolated to give a stock estimate for Manihiki lagoon of 2.0 million�3.2 million pearl oysters. Stocks in Penrhyn lagoon (5.0 million � 4.1 million) and Suwarrow lagoon (around 400 000) were estimated from average densities. The wide confidence limits mean that other methods are needed to monitor changes in abundance over time. Penrhyn and Suwarrow lagoons have not recovered from earlier overfishing. No pearl oysters occurred below 36 m. Density and shell size increased with depth; this was most notable in Manihiki, where fishing was heaviest. Sizes and densities were influenced by bottom type in Manihiki. Density was greatest in the north of Penrhyn and decreased southwards; Manihiki had no density gradient across the lagoon.
Population dynamics and stock management of the black-lip pearl oyster, Pinctada margaritifera (L.), in the Cook Islands, South Pacific
Authors: Sims NA
Published: November 2005

Permanent transects were used to measure changes in abundance of Pinctada margaritifera in Manihiki lagoon, Cook Islands. Growth in situ, mortality and recruitment were also studied. A correction factor for searcher efficiency was also determined, allowing earlier estimates of standing stocks to be adjusted. Overall abundance in Manihiki decreased by 18% in one year. Most losses were attributable to fishing (F=0.19; M=0.11). Mortality (27%) and recruitment (9%) were presumably underestimated because of heavy fishing of juveniles. Total mortality, estimated by Wetherall plots, decreased from 0.48 to 0.35 over the year owing to a decline in fishing for larger oysters. The average shell diameter of recruits was 110 mm. This was also an approximation of Ic,. von Bertalanffy growth parameters of K=0.26 and L∞ = 183 mm were estimated from shell size increments. Yield-per-recruit calculations indicate that minimum size limits are not effective. Reserve areas, quotas, and other restrictions on effort should instead be used to protect broodstocks.
Diet in odacid and aplodactylid fishes from Australia and New Zealand
Authors: Choat JH , Clements KD
Published: November 2005

Diets of a number of temperate-water reef fishes considered to be herbivores were examined by stomach content analysis. Two species of the genus Odax (family Odacidae), O. pullus and O. acroptilus, were investigated. Stomach contents of samples of O. pullus from two times and two localities on the New Zealand coast were dominated by fucoid and laminarian algae. There was evidence of selection of reproductive structures of fucoid algae as an important food source. O. acroptilus collected from the central NSW coast of Australia proved to be a carnivore on small benthic invertebrates. In addition, the stomach contents of a taxon unique to Southern Hemisphere waters, Aplodactylus arctidens (family Aplodactylidae), and of one member of a widespread taxon, Girella tricuspidata (family Girellidae), were examined as a comparison with Odax. Collections of each species were made in northern New Zealand. A. arctidens and G. tricuspidata were facultative herbivores with diets dominated by under storey and epiphytic red algae. These results emphasize the unusual feeding patterns of herbivorous odacids and their importance in the development of general models of piscine herbivory.
Population genetics of tailor, Pomatomus saltatrix (Linnaeus) (Pisces: Pomatomidae) in Australia
Authors: Nurthen RK , Cameron R , Briscoe DA
Published: November 2005

Tailor, Pomatomus saltatrix, from the eastern coast of Australia were sampled and typed for nine polymorphic gene loci, using allozyme electrophoresis. Tailor were also sampled from the western coast but were typed for only six of the same nine gene loci. East-coast samples did not differ significantly from each other, apart from the frequency of one allele at one gene locus, and are hence considered as one genetic stock. The west-coast tailor differed significantly from the east-coast tailor at two of the six gene loci and can be considered as a separate stock.
Observations of circulation and exchange processes in Jervis Bay, New South Wales
Authors: Holloway PE , Symonds G , Nunes Vaz R
Published: November 2005

This paper discusses oceanographic observations obtained in and near Jervis Bay, a small coastal embayment of approximately 124 km2 situated on the New South Wales coast, during a series of measurement programmes spanning three years. Various mechanisms that drive water circulation within the bay and water exchange between the bay and the adjacent continental shelf are discussed. Current meter data from within the bay show surprisingly little correlation with the wind. Currents are characterized by persistent flows in one direction for periods of months, and it is suggested that influences from the shelf are responsible for driving the bay circulation. Flow through the bay entrance is weakly correlated with the wind at a period of around eight days, with near-surface inflow on the southern side of the entrance being in phase with deeper outflow on the northern side and vice versa. The shelf waters are well known for their coastally trapped waves. These have the potential to oscillate vertically the density surfaces on the shelf on a time scale of around eight days, and observations indicate that these waves are an additional mechanism driving circulation in the bay. The shelf waters are influenced by the warm East Australia Current and its eddies, and this appears to maintain a density contrast between the bay and the shelf for most of the year, with the shelf waters being less dense, which may be an additional mechanism driving bay circulation. Current-meter data from the bay entrance show a persistent northward current component in contrast to the strong southward flow of the East Australia Current on the shelf. Conductivity-temperature- depth data reveal cold, dense water flowing out of the bay during periods of strong winter cooling and the effects of warm eddies pushing warm water into the bay and displacing cold deeper water away from the bay. The heating/cooling cycle of the bay appears to be influenced by advection processes on the shelf as well as by aidsea heat and radiation exchanges.
Population genetics and zoogeography of Australian freshwater golden perch, Macquaria ambigua (Richardson 1845) (Teleostei: Percichthyidae), and electrophoretic identification of a new species from the Lake Eyre basin
Authors: Musyl MK , Keenan CP
Published: November 2005

Populations of golden perch (Macquaria ambigua) were sampled from both sides of the Great Dividing Range (GDR): from the Murray-Darling drainage basin (Murray R., L. Keepit and Condamine R.), the L. Eyre internal drainage basin (Barcoo R. and Diamantina R.), and the internal drainage basin of the Bulloo R.-all to the west of the GDR-and from the Fitzroy drainage basin (Dawson R. and Nogoa R.) east of the GDR. Starch-gel and polyacrylamide electrophoresis of 12 enzyme systems plus two general muscle proteins was used to estimate the genetic variation within and between populations. Of the 18 presumed genetic loci examined, nine were either polymorphic at the P0.99 criterion level or exhibited fixed allelic differences between some of the populations. Within the Murray-Darling drainage basin, there was little indication of heterogeneity. Contingency Χ2 analyses of allelic distributions among drainage basins indicated significant levels of heterogeneity at six variable loci. The isolated L. Eyre population exhibited diagnostic alleles at four loci when compared with the Murray- Darling and Fitzroy populations. The genetic distance of the L. Eyre population (Nei's D=0.23) from these two populations indicates that the L. Eyre golden perch is most probably a previously unrecognized allopatric species. The level of divergence (0 = 0.06) between Fitzroy and Murray-Darling golden perch indicates differentiation at the subspecies level, with no fixed differences observed between these two populations. Finally, golden perch from the Bulloo R. represent either (i) an intermediate evolutionary unit between the presumed ancestral L. Eyre population and the derived Murray-Darling and Fitzroy populations or (ii) a complex hybrid between these populations. Average gene-flow statistics, FST = 0.760 and Nem=0.08, suggest that the populations in each of the four basins can be regarded as separate gene pools that have been isolated for different, and considerable, periods of time.
Review of the effects of non-point nutrient loading on coastal ecosystems
Authors: Gabric AJ , Bell PRF
Published: November 2005

In many coastal regions (e.g. parts of the North Sea, northern Adriatic Sea, Baltic Sea, Great Barrier
Reef lagoon, wider Caribbean, coastal areas of the USA) there is large-scale, and in some cases chronic,
eutrophication. In some regions, the link between eutrophication and the destruction of an ecosystem
is obvious, with excessive algal growth and water-column anoxia. In other cases, particularly in more
fragile ecosystems such as coral-reef and seagrass areas, the links are not so obvious, yet the impacts
of eutrophication in such regions can be devastating. Eutrophication can have more insidious effects
such as contributing directly to the mortality of fish, marine mammals and sea birds and indirectly to
disease or death in humans owing to the accumulation of biotoxins in seafoods.
Increased development and changes in land-use patterns in the coastal zone have increased the
loading of diffuse or non-point nutrients. In areas subject to runoff and soil erosion, most of the
nutrient load is transported in particulate form. In such cases, the loads of nutrients discharged from
cropping lands are typically an order of magnitude greater than those discharged from pristine forested
areas. Nutrient export from pasture lands, whether these are fertilized or not, is also significantly greater
than that from pristine areas, and in many cases the total loads from such areas are far higher than
those from intensively farmed areas. A reduction in nutrient discharges to coastal waters will require
careful land-use planning. The importance of the particulate fraction in the nutrient load necessitates
effective control of soil erosion. The hydrological and nutrient linkage between terrestrial and marine
ecosystems must be emphasized. Collective management of hinterland and coastal-zone resources could
initiate remediation of a serious and growing problem.
Annually recurrent diatom blooms in spring along the New South Wales coast of Australia
Authors: Hallegraeff GM , Jeffrey SW
Published: November 2005

Blooms of phytoplankton (100-280 mg chlorophyll a m-1) occur on the continental shelf off Sydney
in the spring of most years. These sudden chlorophyll increases (more than 10 times the normal algal
biomass) are due to short-lived diatom blooms that evolve in a predictable sequence from small chainforming
species (Nitzschia, Thalassiosira) to large centric species (Lauderia, Rhizosolenia) and eventually
to large dinoflagellates (Protoperidinium). Two research cruises (October 1981, September 1984) were
conducted to define the longshore extent of this phenomenon. Diatom blooms were widespread along
the whole New South Wales coastline, occurring in the 700-km-long region from Cape Hawke in the
north (32°S), where the East Australian Current separates from the coast, to Maria Island off Tasmania
in the south (43°S). Hydrological mechanisms of these annually recurrent enrichments are related to
the action of the East Australian Current and are unlike those triggering spring blooms in temperate
European waters. Implications of these diatom blooms for coastal fisheries along the New South Wales
coast are briefly discussed.
Benthic macroinvertebrate community structure in streams of different salinities
Authors: Metzeling L
Published: November 2005

The likely effect of salinization on stream invertebrates was studied by comparing macroinvertebrate
community structure at nine sites in six lowland, perennially flowing streams. The salinity of these
streams ranged from 51 to 1100 mg L-1 total dissolved solids (TDS) (and were historically higher,
up to about 2000 mg L-1 TDS). There was no correlation between either number of taxa or faunal
abundance with salinity. However, multivariate analyses showed distinct invertebrate communities
associated with different salinities. Fidelity analysis identified groups of taxa associated with either low
or high salinity. Existing information on the distribution of the common taxa within these groups
indicated that they were tolerant of wider ranges in salinity than those found in this study. The rare
taxa most clearly distinguished between sites of different salinities and are possibly more sensitive to
changes in salinity.
Life histories of six species of Leptoceridae (Insecta: Trichoptera) in Victoria
Authors: St.Clair RM
Published: November 2005

Life history studies were carried out for populations of six species of Leptoceridae. Study sites were
a permanent river (Acheron), a temporary river (Lerderderg) and a permanent lake (Monash University).
Life histories varied in degree of synchrony of larval development, in length of adult emergence period,
and from bi- to semivoltine. Oviposition requirements of adults were found to be the major factor
influencing synchrony of the life history of one species. Life history features did not ameliorate the
effects of the severe drought of 1982-83, nor did drought result in large changes in life histories.
Prevalence of Cabirops orbionei (Epicaridea; Cryptoniscidae) in northern Australia: A biocontrol agent for bopyrids
Authors: Owens L
Published: November 2005

In the Gulf of Carpentaria, bopyrids cause a loss of production to prawn fisheries
due to sterilization. On the east coast of Queensland, the cabiropsid hyperparasite
Cabirops orbionei sterilizes bopyrids. The hyperparasite was examined as a
possible biocontrol agent for bopyrids. An ANOVA linear model using main
effects only, was fitted to the data and accounted for 41% of the variability in
the intensity of infection. Month, bopyrid reproductive status, prawn species,
area of sampling, bopyrid species and prawn size accounted, respectively, for
10, 10, 7, 6, 5 and 3% of the explained variability. Prevalence of C. orbionei
dropped from a maximum of 50% in February to a minimum of 10% in August
before starting to rise again. Hyperparasitized bopyrids were usually fully
sterilized by the cabiropsid. The most commonly hyperparasitized prawn
was Penaeus esculentus, followed by Penaeus sernisulcatus, Penaeus
longistylus and Penaeus latisulcatus; Metapenaeus endeavouri was not
infected at all. Prevalence was almost uniform from Torres Strait to Halifax
Bay but dropped precipitously at Cape Upstart. Epipenaeon ingens was 4-5
times more heavily infected than other bopyrid species. Prevalence of C.
Orbionei rose to a maximum at 34-36 mm carapace length of prawn and
dropped slowly thereafter.
Aspects of the hyporheic zone below the terminus of a South Australian arid-zone stream
Authors: Cooling MP , Boulton AJ
Published: November 2005

Diel variation in physicochemistry and assemblage composition of the hyporheos, below and beyond
the terminus of an arid-zone intermittent stream, was studied in Brachina Creek, Flinders Ranges, South
Australia. Surface water downwelled at the terminus, and physicochemical conditions in the hyporheic
zone at 30 cm resembled those in the stream above. With increasing distance beyond the terminus and
presumably greater hyporheic residence time, diel fluctuations in water temperature and dissolved oxygen
became dampened, and were absent 80 m beyond the terminus. At least 31 taxa were collected, 19 of
which were surface species temporarily occupying the hyporheic zone. These epigean taxa commonly
occurred as tiny instars in the hyporheos below the stream in regions of strong downwelling. Further
downstream, the hyporheos became dominated by phreatic species (e.g. blind amphipods, syncarids)
that are obligate subsurface residents. At the most downstream site, where dissolved oxygen concentrations
were lowest and water temperatures highest, species richness was least, although biomass
(mainly amphipods) was greatest. There was no diel variation in assemblage composition, species
richness, total abundance and biomass, or the abundance of common species at any of the sites below
the stream. The longitudinal pattern in the spatial distribution of the hyporheos appeared to be related
to stream hydrology (downwelling), bed permeability, and the hyporheic residence time of the water.
Use of acoustics to assess a small aggregation of orange roughy, Hoplostethus atlanticus (Collett), off the eastern coast of Tasmania
Authors: Elliott NG , Kloser RJ
Published: November 2005

A relatively small aggregation of orange roughy (Hoplostethus atlancticus) was located in April 1989
off the eastern coast of Tasmania. A Simrad EK400 (38 kHz) scientific echo-sounder was used to survey
the aggregation over a period of eight days, during which time the aggregation was commercially fished.
The aggregation was confined to an area of approximately 4 km2, with the dimensions of the aggregation
varying within and between days. High densities of orange roughy were located near the bottom
on some days and more than 24 m off the bottom on others. Average fish densities during the survey
and an estimate of the extremes of densities (fish m-3) are presented. Estimates of the original biomass
of this aggregation as obtained from acoustic data and commercial catch-and-effort data are compared,
and the mean target strength of the population is estimated.
Reproductive cycle of the common guitarfish, Rhinobatos rhinobatos (Linnaeus, 1758), in Alexandria waters, Mediterranean Sea
Authors: Abdel-Aziz SH , Khalil AN , Abdel-Maguid SA
Published: November 2005

The common guitarfish, Rhinobatos rhinobatos, is an ovoviviparous fish having a gestation period
of about nine months and a mean reproductive rate of 8 to 14 progeny per pregnancy. Data on
gonadosomatic index, maximum ovum diameter, size frequency of ova, and ovarian and uterine
contents for 438 specimens (236 females and 202 males), analysed on a monthly basis, indicated
a distinct seasonal reproductive cycle for R. rhinobatos. Females reached a maximum size of 181 cm
and 20 kg, whereas the maximum size of males was 172 cm and 16 kg. Lengths at which 50% of
specimens were mature were 87 and 70 cm for females and males, respectively. Ovarian egg size
and male gonadosomatic index both peaked in July and August, indicating that mating occurred in
summer. Uterine eggs were present from late February through July, but no embryonic development
was evident. Females with full-term embryos were observed in late August, and parturition was followed
immediately by ovulation. Ovarian fecundity ranged from 8 to 27 (mean 18) eggs per fish, whereas uterine
fecundity ranged from 8 to 14 (mean 12) eggs or embryos per fish.
Genetic subdivision of the pearl oyster Pinctata maxima (Jameson, 1901) (Mollusca: Pteriidae) in northern Australia
Authors: Johnson MS , Joll LM
Published: November 2005

The genetic structure of the pearl oyster Pinctada maxima in northern Australia was investigated by
starch-gel electrophoresis. Six polymorphic enzymes were examined in 220 individuals from five
areas which span a distance of 3400 km. Across this range, the average FST is 0.104, with three
of the loci showing highly significant variation in allelic frequencies. Most of the geographic variation
is clinal between western and eastern populations. Particularly striking is the near substitution of
alternate alleles for GOT between Western Australia and north-eastern Queensland. Comparisons
between adjacent pairs of samples usually revealed significant genetic differences, including
differences between two areas in the Northern Territory separated by 320 km. In contrast, two
samples from Western Australia showed little evidence of genetic subdivision over a distance of
more than 800 km. These genetic comparisons indicate that stocks of P. maxima are highly
subdivided in northern Australia, but they also favour the view that there are substantial connections
of Western Australian populations over large distances.
Stream ecology and surface-hyporheic hydrologic exchange: Implications, techniques and limitations
Authors: Boulton AJ
Published: November 2005

In many streams with coarse substrata, there is continuous exchange between surface water and
interstitial (hyporheic) water. Upwelling hyporheic water usually contains less dissolved oxygen
and may provide nutrients that are limiting in the surface water. Downwelling stream water carries
oxygen, surface detritus and other material to the hyporheic zone where microbes and invertebrates
reside. The magnitude and direction of this hydrologic exchange can be measured using relatively
simple techniques (such as dye injections and mini-piezometers) although there are some important
limitations to consider. As hydrologic exchange has been shown to affect the distribution of benthic
algae and invertebrates in some streams, this variable has implications for a variety of lotic studies
including those of drift, leaf breakdown, benthic invertebrate colonization, sedimentation, and nutrient
limitation. Experiments in flumes and artificial stream channels usually remove the influence of hydrologic
exchange although it would be possible to incorporate this into their design. Stream ecologists should
consider assessing the significance of the hyporheic zone to surface processes by quantifying the
vectors of hydrologic exchange to ascertain how these may affect results of work conducted on the
benthos at a variety of scales.
Schooling behaviour of jack mackerel, Trachurus declivis (Jenyns), observed in the Tasmanian purse seine fishery
Authors: Williams H , Pullen G
Published: November 2005

The seasonal, lunar and diurnal changes in schooling of jack mackerel were examined using log-book
information collected from an industrial fishery off the east coast of Tasmania between 1985 and 1989.
School size increased significantly from spring to autumn. The ratio between surface and subsurface
schools encountered by the fishery also changed seasonally. Surface schools predominate during summer,
whereas subsurface schools become more frequent during autumn. The fishery was predominantly a day
fishery and no lunar effects on catch rates or fishing intensity were detected. Catches mainly comprised
jack mackerel, although redbait (Emmelichthys nitidus Richardson) and blue mackerel (Scomber australasicus
Cuvier) were a significant by-catch. In summer, schools were almost exclusively composed of jack mackerel,
but in other seasons mixed schools were found. Data presented, together with evidence from other sources,
suggest that the availability of schools to the fishery may be closely related to the availability of feed.
Genetic analysis of populations of north-western Australian fish species
Authors: Johnson MS , Hebbert DR , Moran MJ
Published: November 2005

Allozyme variation was used to investigate the genetic structure of Lutjanus sebae, Lethrinus nebulosus,
Lethrinus choerorynchus, and Epinephelus multinotatus, which are components of a multispecies fishery
off north-western Australia. Samples of each species were obtained from five or six localities, over a
total distance of 1400-2080 km. Allelic variation was found at 13-16 loci in each species. The consistent
picture to emerge was one of little genetic subdivision in all four species, with average values of FST
ranging from 0.003 in L. sebae to 0.012 in E. multinotatus. Although there was statistically significant
variation in allelic frequencies in three of the species, there were no clear geographical groupings of
populations. With the possible exception of clinal variation for aldehyde oxidase in E. multinotatus, all
heterogeneity of allelic frequencies was within the range that could easily be due to within-generation
effects of selection. Thus, the allozyme data are consistent with the view that there are extensive connections
of populations over large distances. The electrophoretic study also confirmed that, contrary to suggestions in
the literature, L. nebulosus, L. choerorynchus, and Lethrinus laticaudis are reproductively isolated species.
One-parent removal experiment in the brood-caring damselfish, Acanthochromis polyacanthus, with preliminary data on reproductive biology
Authors: Nakazono A
Published: November 2005

One-parent removal experiments were carried out in the monogamous damselfish Acanthochromis
polyacanthus at One Tree Island, Australia, from 27 October to 4 November 1987. In eight of nine
removal experiments, the vacant place was refilled by intrusion of another adult fish within two days.
This was followed by the disappearance of the fry. A small number of fry was found in the stomach of
one intruder, suggesting cannibalism. Those fry that were not eaten were abandoned by the adults and
left to a free existence, but their survival was very low compared with fry tended by both parents.
Analysis of fecundity suggests that females have the potential to lay a second clutch of nearly 200 eggs
when the first one is lost. It seems that A. polyacanthus, on the loss of a partner, takes a new partner and
deserts the current brood rather than trying to rear them alone. This implies that survival is lower in
uniparental broods. The plasticity of the pair-bond and the fecundity of females suggest that death of
brooding parents may be a relatively common event in the predator-rich environment of coral reefs.
No evidence for seasonality in the ectoparasitic fauna of slimy mackerel, Scomber australasicus
Authors: Perera KML
Published: November 2005

Fifteen (or sixteen) species of ectoparasites-6 monogeneans, 4 (or 5) trematodes, 2 copepods, 1 isopod,
1 cestode, and unidentified cysts -were collected from 428 Scomber australasicus individuals caught at
Eden, New South Wales, Australia, between November 1988 and June 1992. Neither common nor rare
parasites of slimy mackerel showed seasonal variation in abundance or prevalence. Only the copepod
Brachiella magna occurred more frequently on larger (older) fish than smaller (younger fish).
Two monogeneans (Kuhnia scombri, Pseudokuhnia minor), 2 didymozoids, and unidentified cysts
occurred more frequently on smaller than larger fish. The intensities of the remaining monogeneans
(Kuhnia scombercolias, Kuhnia sprostonae and Grubea australis), 1 didymozoid, 1 copepod (Peniculus sp.),
the isopod (Ceratothoa imbricata) and a trypanorhynch cestode were not significantly correlated with fish length.
Characteristics and implications of high-level slackwater deposits in the Fairlight Gorge, Nepean River, Australia
Authors: Saynor MJ , Erskine WD
Published: November 2005

The largest recorded flood on the Nepean River, with a peak discharge of 16 600 m3 s-1,
occurred in 1867. Detailed field descriptions and particle-size analyses of sediments at
six sites in the Fairlight Gorge below Warragamba Dam identified high-level flood deposits.
Slackwater deposits (SWDs) are typically fine-grained sand and silt, which accumulate rapidly
from suspension during large floods in areas where flow velocities are locally reduced. However,
the higher-level SWDs were too thin and bioturbated to be clearly differentiated from locally derived
colluvium. Heavy-mineral analysisof the very fine sand fraction of these high-level SWDs identified
minerals (epidote and pyroxene) that were not present in the surrounding bedrock. Epidote and
pyroxene were derived from distant sources and were emplaced by at least one palaeoflood.
A radiocarbon date of 3756�72 years BP was obtained by tandem accelerator mass spectrometry
on small fragments of charcoal contained in the high-level SWDs. Therefore, at least one palaeoflood
larger than any historic flood occurred during the late Holocene. SWDs indicated that the largest
palaeoflood had a peak height at least 8.0 m higher than the 1867 flood. If such a flood had occurred
before the recent raising of the dam wall, the dam would have sustained substantial damage and might
have failed. Additional modifications are being discussed; it is recommended that they should be
completed as soon as possible to allow Warragamba Dam to discharge safely floods of similar magnitude
to the largest palaeoflood indicated by SWDs.
Distribution, upstream migration and habitat selection of maturing lampreys, Geotria australis, in Pigeon Bay Stream, New Zealand
Authors: Kelso JRM , Glova GJ
Published: November 2005

Adult lampreys, Geotria australis, began to enter Pigeon Bay Stream just before 7 August 1992.
Lampreys moved upstream more or less en masse, because adults were found immediately
above the tidal limit in August but at the mouths of headwater streams in late October. Capture
rates of adult lampreys in fyke-nets were irregular and appeared to reflect the movement of the fish
through stream sections as upstream migration occurred. The daily distance travelled by lampreys
individually equipped with radio transmitters declined from a high of 87.8 m to 0 m between August
and November. Lampreys typically selected the spaces formed under boulders, usually 25 cm in diameter,
at the bottom of riffles and at the upstream ends of pools. With only one exception, lampreys were
never seen above the surface of the substratum. Movement occurred only at night and at the onset of
freshes. Even though upstream movement had ceased for some two to four weeks, lampreys had
not spawned and gonads remained far from mature by 30 November 1992.
Effect of salinity on four freshwater macrophytes
Authors: James KR , Hart BT
Published: November 2005

The sublethal effects of salinity on four freshwater macrophyte species commonly found in floodplain
wetlands in north-eastern Victoria (Myriophyllurn crispaturn, Eleocharis acuta, Potarnogeton
tricarinatus and Triglochin procera) are reported. These species taken from the same freshwater
wetland showed a wide range of salt sensitivities; P. tricarinatus was the most sensitive followed by
M. crispatum and then E. acuta and T. procera. A progressive depression of growth rate and plant
size was observed for each species when grown at salinities greater then 1000 mg L-1. The onset
of these changes in growth pattern occurred earlier at the higher salinities. Both sexual and asexual
reproduction were blocked in M. crispatum at salinities greater than 1000 mg L-1, even though 52%
of plants survived after 72 days growth in water of salinity 7000 mg L-1.
Cadmium in the saucer scallop, Amusium balloti, from Western Australian waters: Concentrations in adductor muscle and redistribution following frozen storage
Authors: Francesconi KA , Moore EJ , Joll LM
Published: November 2005

Geographic and seasonal variations in the concentration of cadmium in the adductor muscle
of saucer scallops, Amusiurn balloti, were determined for scallops collected from five sites
off the Western Australian coast throughout 1985. Mean cadmium concentrations for adductor
muscles from whole frozen scallops from each of the five sites ranged from 0.41 to 1.44 mg kg-1
wet weight and were below the maximum permitted concentration of 2.0 mg kg-1 set by the
Australian National Food Authority. Most of the cadmium (about 80% of the total) in the scallops
was in the non-edible digestive gland. Subsequent work revealed that adductor muscles of whole
frozen scallops contained more cadmium than did adductors of scallops that had been processed
live because of redistribution of cadmium from the digestive gland, with the degree of redistribution
depending on the time in frozen storage. Cadmium in A. balloti from Western Australian waters
was likely to be of natural origin because the highest concentrations were found in animals collected
in remote areas where human activities have had no significant effect.
Reproductive biology and sexual maturity of female jack mackerel, Trachurus declivis (Jenyns), in eastern Tasmanian waters
Authors: Marshall J , Pullen G , Jordan A
Published: November 2005

The reproductive biology of female jack mackerel, Trachurus declivis, was determined from
fish sampled from November to March, 1987 to 1991, from commercial purse-seine catches
and research trawling. Histological, microscopic and macroscopic techniques were used to
examine the ovaries of T. declivis. Half of the female fish were sexually mature (Stage 3) at
31.5 cm fork length, and all fish were mature by 37.0 cm fork length. Oocyte development and
pre-ovulatory atresia were similar to those of other species of the same genus. The size-frequency
distribution of oocyte diameter was polymodal, indicating serial spawning. Atresia was present
in all oocyte stages studied, with its occurrence increasing with increasing stage of development.
Despite sampling during the spawning season, post-ovulatory follicles were not found, possibly
owing to rapid reabsorption or to spawning fish not being vulnerable to the sampling gear.
Movement of tagged juvenile tailor (Pomatomus saltatrix) in Moreton Bay, Queensland
Authors: Morton RM , Halliday I , Cameron D
Published: November 2005

Large quantities of tailor, Pomatomus saltatrix, are caught by recreational and commercial
fishers in coastal waters off New South Wales and Queensland. Juvenile tailor were subject
to increasing fishing mortality in Moreton Bay (Queensland) in the mid 1980s. A tagging
programme, involving State Government fisheries biologists and amateur fishing clubs, was
established in 1986 to examine the movement, growth rate and fisheries exploitation of juvenile
tailor (<270 mm fork length) in Moreton Bay. Of 2173 juvenile tailor tagged in Moreton Bay during
February-July and December 1987, 237 were recaptured over a period of 30 months,
representing a recapture rate of 11%. This was a high recapture rate compared with those in
similar finfish tagging studies carried out in Moreton Bay. The recaptured fish moved relatively
short distances (mean�s.d., 10.2 � 15.0 km; maximum distance, 85 km). Growth data were
unreliable. Estuaries such as Moreton Bay function as nursery areas for tailor prior to their
movement onto open surf beaches as adult fish. A legal minimum length for tailor was introduced
on the basis of this study.
Distribution of chlorophenolic compounds, from a pulp mill, in Lake Bonney, South Australia
Authors: Van Leeuwen JA , Nicholson BC , Hayes KP
Published: November 2005

Water and sediment samples from Lake Bonney (south-eastern South Australia) were
collected at various distances from the effluent discharge point of a sulfite-based pulp
mill and analysed for chlorophenolic compounds. The period of sample collection (July
1991 to January 1992) occurred during a time when bleaching process of the mill was
being converted from using molecular chlorine to using hydrogen peroxide. In water
samples, the major chlorophenolic compounds detected were 2,4,6-trichlorophenol,
tetrachlorocatechol and chlorinated guaiacols. In sediment samples, the major
chlorophenolic compounds detected were chlorinated guaiacols and chlorinated
catechols. The concentrations of these compounds in lake water generally decreased
over the sampling period, corresponding to the decrease in use of molecular chlorine.
Concentrations in sediment decreased with increasing distance from the discharge point.
The presence of chlorinated guaiacols in water and sediment at a site 17 km from the effluent
discharge point indicated that these compounds degrade slowly in the lake.
The presence of the chlorinated catechols in sediments at localities where these compounds
were not detected in the water suggests that de-0-methylation of adsorbed chlorinated guaiacols
occurs and/or that there is preferential adsorption of chlorinated catechols to sediment.
Temporal and spatial variation in the abundance of fish associated with the seagrass Posidonia australis in South-eastern Australia
Authors: Ferrell DJ , McNeill SE , Worthington DG , Bell JD
Published: November 2005

A beam trawl was used to sample fish associated with the seagrass Posidonia australis
between September 1988 and June 1990. We describe variation in abundance of fish
at two spatial scales: among three seagrass beds 1-10 km apart within each of three
estuaries, and among the estuaries separated by at least 100 km. Most species had
significant differences in abundance among sites and estuaries that changed through time.
However, many species also had consistent patterns in abundance among sites and among
estuaries. For example, there were large and consistent differences in the abundance of
many species among the three estuaries. Widespread changes in abundance (ie: changes
that took place at all sites within an estuary or in most estuaries) were not common.
The two spatial scales used in this study are also logical scales for management of seagrass
habitats. The consistent differences in abundance of some fish found at both spatial scales
will complicate management decisions.
Laboratory study of the effect of light on the emergence behaviour of eight species of commercially important adult penaeid prawns
Authors: Wassenberg TJ , Hill BJ
Published: November 2005

The emergence behaviour of eight species of commercial prawns (between 25.0 and 30.0 mm carapace
length) was studied in the laboratory. All except Penaeus merguiensis were nocturnal: they emerged from
the substratum in the evening when the light was dimmed and buried themselves in the morning, usually
before dawn. P. merguiensis generally remained on the substratum during the day. The species can be
grouped on the basis of their behaviour: the first group (P. plebejus and P. latisulcatus) was most
sensitive to light, the second group (P. semisulcatus, Metapenaeus ensis, P. esculentus, M. endeavouri
and M. bennettae) was less sensitive to light, and the third (P. merguiensis) was least sensitive to light.
To find out what triggered emergence, two species (P. esculentus and P. plebejus) were exposed to
different rates of light dimming at dusk. Both species responded to absolute light intensity, but the
response of P. plebejus was affected by the rate of change of light intensity.
The different responses of the species to different light intensities explains some of the differences
in catchability in a multi-species prawn fishery.
Discrimination of algal and bacterial alkaline phosphatases with a differential-inhibition technique
Authors: Boon PI
Published: November 2005

Both phytoplankton and bacterioplankton produce alkaline phosphatases, but the techniques currently
available for discriminating between the two sources are poor, especially when samples are from turbid
waters. A novel approach, based on the differential inhibition of alkaline phosphatases by various
physical and chemical treatments, was assessed as a rapid and inexpensive technique for determining
whether phytoplankton or bacterioplankton were the more important producers of alkaline phosphatases
in turbid rivers of south-eastern Australia. Eight phytoplankton strains and 14 bacterial strains (eight
isolated from the Ovens River and six isolated as bacterial contaminants of the phytoplankton cultures)
were grown in laboratory culture. Rates of alkaline phosphatase activity in the bacterial cultures varied
from <1 to 21 fmol cell-1 day -1.
Rates for phytoplankton were usually < 5�mol (�g chla) -1 day-1 but could reach 128 �mol (� chla)-1 day-1,
depending on whether inorganic or organic phosphorus was supplied. Differential-inhibition profiles were
determined for the 22 isolates, using seven chemical treatments (L-cysteine, EDTA and L-levamisole,
and Zn2+ and Cu2+ each at two concentrations) plus one physical treatment (thermal deactivation).
The alkaline phosphatases of the three microbial groups (i.e. Ovens River bacteria, bacteria isolated as
contaminants from algal cultures, and phytoplankton) could be classified with a predictive accuracy of better than 90% when these data were
analysed with Discriminant Function Analysis. L-Cysteine, Zn2+ and Cu2+ were the best predictors of
class membership; thermal deactivation and EDTA sometimes were also significant. Inhibition profiles
were then determined for the alkaline phosphatases of various river-water samples. These environmental
samples usually (>70% of cases) grouped separately from those of the laboratory cultures of bacteria
and phytoplankton, perhaps because the microbes studied in laboratory culture were not representative
of native assemblages or because the culture conditions did not mimic those in nature. Nevertheless,
differential-inhibition techniques have much potential for determining the origin of the alkaline
phosphatases found in natural waters, with the major factor limiting their application being the
collection of valid inhibition profiles for native bacterial and algal communities.