bluuebunny/crossref_metadata_2025 huggingface dataset:
Description of the subareas of Ragay Gulf, Philippines, and their fish assemblages by exploratory data analysis
Authors: Federizon RR
Published: November 2005

Exploratory data analysis using four different techniques of classification and ordination was applied
to the catch data from a 15-month demersal trawl survey in Ragay Gulf, Philippines, in order to
characterize the area. The four techniques yield almost identical results and therefore lend confidence
to the three subareas identified: shallow, coralline and deep. Species characteristic of the subareas were
also identified. The observed pattern remained consistent during the study period, suggesting that
seasonal variability is not pronounced.
This study provides further empirical evidence of the zonation of fish communities by depth.
Preliminary comparison of the results of this study with those of studies of demersal fish community
assemblages in the Samar Sea shows that boundary depths defining zonation are different in the two
areas because of their different depth ranges and spatial scales. This comparison leads to the question
of whether the boundary depths as identified via classification and ordination methods could be a
function of the shape of the depth distribution of the samples. The use of a bootstrapping method to
investigate this question is suggested. The importance of applying exploratory data analysis to the catch
data from a demersal trawl survey done to assess fish stocks is also discussed.
Reproductive cycles of the bivalva molluscs Atactodea striata (Gmelin), Gafarium tumidum Roding and Anadara scapha (L.) in New Caledonia
Authors: Baron J
Published: November 2005

Monthly samples of the bivalves Atactodea striata, Gafrariurn turnidum and Anadara scapha were
collected over 1 year from the littoral zone on the south-western coast of New Caledonia. A. striata
and G. turnidum were studied by macroscopic examination of gonads and microscopic examination of
gamete smears. For A. scapha, only microscopic examination was used. A. striata and G. turnidum
are dioecious, whereas A. scapha is a protandric hermaphrodite. Sexual differentiation begins at a shell
length of 20 mm for A. striata and G. turnidum and 22 mm for A. scapha. The three species have an
extended or continuous breeding period, although, in all three, sexual activity peaks in the hot season.
Karyotype of Lasaea australis, a brooding bivalve species
Authors: Thiriot-Quievreux C
Published: November 2005

Karyological investigations have been carried out on the only known cross-fertilizing Lasaea species,
L. australis, a marine brooding bivalve with a pelagic larval development. The karyotype consists of
18 pairs of chromosomes (2n = 36), including four metacentric, six submetacentric, three subtelocentric
and five telocentric pairs. Comparison with other known Lasaea karyotypes shows that L. australis
can be considered as ancestral, and its asexual and direct-developing congeners are characterized by
mechanisms of polyploidy.
Distribution of seagrasses, substratum types and epibenthic macrobiota in Torres Strait, with notes on pearl oyster abundance
Authors: Pitcher CR , Skewes TD , Dennis DM , Prescott JH
Published: November 2005

The benthic habitat of Torres Strait was surveyed in May-June 1989, using almost 600 transects (each
4 × 500 m) randomly dispersed over an area of about 25 000 km2. The distribution and relative
abundance of seagrasses were estimated visually and mapped, along with the distributions of substratum
types and epibenthic macrobiota; pearl oyster abundance was also estimated. Seagrasses were seen in
most transects and, though very patchy at small scales, tended to increase from almost zero abundance
in the southern and eastern areas of the survey to moderately dense in north-western Torres Strait.
The epibenthic macrobiota and the substratum type also varied greatly, with the greatest diversity and
abundance of biota associated with the harder substrata. The survey area supported an estimated
1.2-2.5 million pearl oysters, and though their density varied significantly with habitat type, the latter
accounted for only about 12% of the variance.
Behaviour of copper and zinc added to the Tambo River, Australia, by a metal-enriched spring
Authors: Hart BT , Sdrauling S , Jones MJ
Published: November 2005

A study of the behaviour of Cu and Zn added to the upper Tambo River, Australia, by a metal enriched
but neutral-pH spring (Wilga Spring) is reported. Approximately 80% of the Cu, Zn, Fe and
Mn liberated in the oxidation zone associated with the Wilga orebody is deposited within the groundwater
system before the spring water enters the Tambo River. Acidic water from the oxidation zone
is neutralized by carbonate-rich groundwater.
The input of the spring to the Tambo River, which occurs through the base of the river over a
distance of 150-200 m, causes an average sixfold increase in the Cu and Zn concentrations and a
measurable increase in the sulfate concentration, but no significant decrease in the pH, in the 'active
region' of the river, a distance of approximately 1.3 km. Over the 1-year study period, the spring added
an estimated 120 kg of Cu (about 65% in filterable forms) and 230 kg of Zn (about 50% in filterable
forms); these fluxes are approximately six times larger than those transported from the upper catchment.
The spring also adds an estimated 14.5 t of sulfate, this being roughly the same as the amount
(10.7 t) that is transported from the upper catchment. On average, the spring adds only small quantities
of Fe and Mn.
The concentrations of filterable (or dissolved) Cu and Zn in the 'active region' are largely controlled
by adsorption onto iron oxyhydroxide surfaces associated with the particulate matter. At high concentrations
of filterable metals, the active surfaces apear to be saturated with Zn and possibly Cu.
At river flows in excess of 5-10 ML day-1 (the mean annual river flow is about 22 ML day-1), little
Cu and Zn appears to be lost from the water column. The difference in metal concentrations between
the 'active region' and Blackfellows Flat (a distance of 10 km) can be explained mostly by dilution of
the metal-enriched water in the main branch with water from the southern branch. At low river flows,
considerable quantities (up to 99%, depending upon flow) of the Cu, Zn, Fe and Mn added by
Wilga Spring are deposited in the 'active region' between the spring and Formfit Creek.
Short Communication: Litterfall in riparian and ajacent forest zones near perennial upland stream in the Australian Capital Territory
Authors: Thomas K , Chilvers GA , Norris RH
Published: November 2005

Litterfall into Lees Creek from eucalypt-dominated riparian vegetation and litterfall in adjacent
eucalypt forest was measured monthly for 2.5 years. Mean annual litterfall for riparian vegetation was
4.52 t ha-1, of which overstorey leaf fall accounted for 44%, understorey leaf fall 12.5%, twigs
16.75%, bark 12% and miscellaneous material 14.75%. Mean annual litterfall in adjacent forest was
4.20 t ha-1, of which overstorey leaf fall accounted for 52.3%, understorey leaf fall 2.9%, twigs
18%, bark 12% and miscellaneous material 14.8%. More than 50% of all litterfall occurred from
December to March with leaf fall the largest component (60-70%) during this period. Minimum litterfall
was in winter with twigs contributing up to 40% of total litterfall during this period. Timing of
litterfall into Lees Creek and the adjacent forest is similar to litterfall in other Australian forests and
to litterfall from sclerophyllous vegetation into streams of the south-western Cape of South Africa.
Reproductive biology, spawning and field fertilization rates of Acanthatser planci
Authors: Babcock RC , Mundy CN
Published: November 2005

Gametogenesis and reproductive behaviour of Acanthaster planci were observed at Davies Reef between
September 1990 and February 1991. Gonad development in females and males of A. planci peaked in
early December 1991. Mean gonad volume then decreased by about 50% following a major spawning
in which at least two-thirds of the population participated. Mean gonad volume recovered to near
prespawning values by mid January, despite a further minor spawning that was observed in the
population. Further spawnings are likely to have occurred in mid- to late January.
Fertilization rates measured during natural spawnings of A. planci were highest (83%) in samples
taken at the peak of a major spawning event and much lower (23%) in samples taken at the end of
the same spawning event. Trials conducted with starfish artificially induced to spawn indicated that
potential fertilization rates decreased relatively slowly as distances between female and male animals
increased. Fertilization rates were 47% for animals separated by 32 m. For animals separated by more
than 60 m, fertilization rates were 23%. The distances at which these fertilization rates were achieved
were two orders of magnitude greater than those recorded for other marine organisms, most likely
because of the large volumes of gametes that A. planci can release.
Short Communication: Observations of crown-of-thorns strafish spawning
Authors: Gladstone W
Published: November 2005

Individual and group spawning events of crown-of-thorns starfish (Acanthaster planci) were observed
in the Whitsunday region, Great Barrier Reef, on the afternoon of 5 December 1990, during a falling
tide, 2 days after a spring tide. Not all individuals in the group spawned, and only a single female
spawned. The behaviour of the starfish during spawning is described.
Enhancement of larval and juvenile survival and recruitment in Acanthatser planci from the effects of terrestrial runoff: a review
Authors: Brodie JE
Published: November 2005

A number of authors have hypothesized that outbreaks of the crown-of-thorns starfish (Acanthaster
planci) are initiated by increased larval survival. This is then linked to the presence, in the water
column, of various components of terrestrial runoff (pesticides, lowered salinity, nutrients, and dissolved
and particulate organic matter) during the pelagic larval stage of the starfish. A related hypothesis
suggests that recent outbreaks on the Great Barrier Reef (GBR) are initiated by the eutrophic condition
of the GBR lagoon. It is claimed that this eutrophication is caused by anthropogenic input of
terrestrially derived nutrients.
The present paper reviews current knowledge of the possible influence of components of terrestrial
runoff on various stages in the life cycle of larval and juvenile A. planci. Processes that could be most
influenced by enhanced nutrient conditions are those of planktonic survival, settlement success and
juvenile survival. Available data on the state of eutrophication of parts of the GBR lagoon do not
support assertions of general eutrophication but do suggest that elevated nutrient conditions exist in
localized areas and that this may be caused by terrestrial runoff. The areas affected coincide with areas
suggested as the primary initiation areas of two waves of crown-of-thorns outbreaks.
Further research required to understand larval survival includes studies on differences in the kinds
and amounts of food available to A. planci larvae in low- and high-nutrient conditions, the effects of
elevated nutrients on coralline algae and their associated bacteria and hence larval settlement processes,
and the offshore effects of river-borne nutrients in coral reef regions.
Short Communication: Recruitment of Acanthaster planci over a five-year period at Green Island Reef
Authors: Fisk D
Published: November 2005

The distribution and abundance of crown-of-thorns starfish was studied at Green Island from 1986 to
1990. The abundance of Acanthaster planci declined over this period. The highest densities of starfish
now occur in two areas of high coral cover. In 1990, a possible cohort was present with a mode of
26-30 cm diameter, which is larger than that of previous years. Growth in this cohort was evident after
several years in which no growth was detected. Only two 0+ year starfish were found in four intensive
broad-scale rubble-sampling surveys (1986 to 1989), suggesting low or very patchy recruitment. These
patterns suggest that either (i) there have been only low rates of recruitment since 1986, or (ii) the
present starfish population arose from localized settlement in 1988 that was not detected in 1989, or
(iii) subadult and adult starfish moved to areas of high coral cover from other parts of the reef
depauperate in coral.
Sediment-rejection mechanisms of 42 species of Australian scleractinian corals
Authors: Stafford-Smith MG , Ormond RFG
Published: November 2005

Mechanisms of sediment rejection by 42 species of Scleractinia from 31 genera, all with wide Indo-Pacific distributions, were investigated in situ and in the laboratory at Lizard Island, northern Great
Barrier Reef. Rejection mechanisms of flat tissues (generally six replicates plus controls) were studied
in response to a single rapid influx of 50 mg cm-2 of 70/30% calcium carbonate/quartz sediment
of each of four particle sizes: silt (<63 pm), fine sand (63-250 μm), coarse sand (500 μrn to 1 mm),
and granules (1-3 mm). Additional observations were made of responses to variations in sediment loads
(to a maximum of 1000 mg cm-2) , to individual sediment particles, and to less-dense organic sediment
and food, as well as of the effects of tissue angles, colony morphology, and in situ environmental
conditions.
Ciliary currents, tissue expansion, and mucus entanglement occur in all of the species studied.
Direct tentacle manipulation and pulsed partial contraction of the polyp or coenosarc also occur but
were not observed in all species. Mesenteries may play a subsidiary or incidental role. Active-rejection
mechanisms are consistent within species and, with the principal exception of some Faviidae species,
are similar for the congeneric species studied.
Species are categorized according to their observed active-rejection capability. This capability is
positively correlated with calice size: all species with large calices (> 10 mm in diameter) are capable
of rejecting influxes of up to at least 50 mg cm-2 of the tested sediment sizes with comparative ease;
those species with small calices (<2.5 mm in diameter), particularly the two Porites species and the
three Montipora species, are poor active rejectors; and other species, notably Acropora hyacinthus and
Pocillopora darnicornis, though having some active-rejection capability, exhibit morphologies that make
active rejection mostly redundant. Species with calices between 2.5 and 10 mm in diameter show more
variation, but all very active rejectors in this size class have strong ciliary mechanisms.
There are differences in the area of a colony involved in the rejection of sediment influxes,
depending on sediment size and density. Rejection of heavy influxes of all sediment sizes is principally
restricted to flat or concave surfaces, whereas individual particles of silt and fine sand as well as light
influxes of silt and almost neutrally buoyant particles of larger sizes frequently require active rejection
from strongly inclined, and even near-vertical, surfaces. The significance of these findings in terms of
energy budgets is discussed.
Estimating the species number and cover of a mangrove-root community: a comparison of methods
Authors: Diaz H , Conde JE , Orihuela B
Published: November 2005

Methods and designs have been validated for sampling coral reefs and reef-associated communities, but
the accuracy and equivalence of results obtained from studies of mangrove-root communities can not
be assured. Thus, it is convenient to establish the accuracy and reliability of sampling methods on a
practical basis. Line interception, point interception, and quadrat sampling were used to estimate several
basic features of the community associated with mangrove roots. Species-number estimates, cover
estimates, sampling efforts, and some statistical properties of the three methods were compared.
A sampling design should be chosen if it yields estimates with the greatest accuracy at the lowest
cost. Results showed that sampling of mangrove roots could start by using 4 × 4-cm quadrats with a
mean sample size of 50 for detecting the number of species, and for establishing species cover it appears
that the point-interception method with a sample size of 50 would be appropriate. The effort involved
in such a sequence would be approximately 10 h for 20 roots. This combined strategy is clearly
laborious and time-consuming in comparison with the use of just a 200-point interception, which would
require only 3.25 h for the same number of roots. Although it would cost more than the above
methods, a fast and accurate technique based upon existing computer hardware to estimate cover from
photographic or video material would result in a census of the whole community. This might prove to
be a reliable way to approach the problem.
Geographical variation ion allozyme frequencies of populations of Penaeus monodon (Crustacea : Decapoda) in Australia
Authors: Benzie JAH , Frusher S , Ballment E
Published: November 2005

This first systematic survey of genetic variation in P. monodon populations in Australia over a wide
geographical range demonstrated highly significant differences in gene frequencies between the west-coast
population and those on the northern and eastern coastlines. Some variation in gene frequencies among
populations within the northern and eastern coastlines was detected in chi-square tests. Several loci
(GPI*, PGM* and MPI*) contributed to the significant differences among populations. Genetic
diversity decreased from east to west, suggesting colonization of the northern and western coasts
by populations from the east after the last opening of the Torres Strait (c. 8000 BP). Evidence of
genetic differences between western compared with northern and eastern populations is now available
for three species of penaeid. These differences suggest, at least, that gene flow over several thousand
years has been insufficient to erase genetic differences evolved during separation. Penaeid populations
may therefore be more structured than has been thought, and the genetic homogeneity emphasized to
date may be a result of the lack of genetic markers rather than a lack of population structure.
Effect of streamer tags on survival and growth of juvenile tiger prawns, Penaeus monodon, under laboratory conditions
Authors: Primavera JH , Caballero RM
Published: November 2005

The effects of streamer tags and initial prawn size on survival and growth in 2-month- and 7-monthold
pond-reared juveniles of Penaeus monodon Fabricius ( 1 1-30 mm carapace length, CL) were assessed
under laboratory conditions. Tagging did not cause immediate mortality in juveniles of 11-21 mm CL
within a one-week period but led to a significantly lower survival rate after 6 to 8 weeks in 1-m3 tanks.
However, tagged prawns of 21-30 mm CL showed high long-term survival rates up to 90% in a
12-m3 tank. The 2-month-old juveniles had lower survival rates than 7-month-old prawns. Specific
growth rate was not affected by tagging but was significantly higher in smaller prawns. In general, there
was no interaction between the effects of tagging and prawn size in terms of growth and survival rates.
The lower long-term survival rate associated with tags may be due to the attractiveness of tags to
predators, or to trauma or stress caused by the weight of the tags. These factors are discussed in
relation to findings for other penaeid species.
Behaviour of the western king prawn, Penaeus latisulcatus Kishinouye: effect of food dispersion and crowding
Authors: Rasheed MA , Bull CM
Published: November 2005

In aquacultural projects, crowding of prawns may adversely influence their growth and survival.
In this paper, the behaviour of western king prawns, Penaeus latisulcatus, was investigated in tanks.
Six forms of behaviour were identified. Prawns were exclusively nocturnal in their active behaviour.
Males and females showed no significant difference in the mean time spent in various behaviours.
Feeding efficiency increased as food became more dispersed over the tank floor. Behaviours leading
to less efficient feeding increased with increased density, but less severely so if food was evenly dispersed
than if food was presented at a point source.
Comparative exploitation exploitation by recreational anglers of brown trout, Salmo trutta L., and rainbow trout, Oncorhynchus mykiss (Walbaum), in Lake Eucumbene, New South Wales
Authors: Faragher RA , Gordon GNG
Published: November 2005

Exploitation rates of syrnpatric brown trout and rainbow trout in Lake Eucumbene, New South Wales,
were estimated from a tagging study. Tag returns were analysed by applying a non-linear regression
method. Tag loss was estimated from a concurrent double tagging study using a maximum likelihood
method. No significant difference at the 5% level was found between the rates of tag loss of the two
species. The annual exploitation rate for rainbow trout was 26.7% (95% confidence interval 24.2-
29.2%) and was significantly less for brown trout, 8.8% (95% confidence interval 4.2-13.5%).
Antibiotic resistance of aquatic bacteria and it's implications for limnological research
Authors: Boon PI
Published: November 2005

The antibiotic resistance of bacteria from the water column of various rivers and billabongs in
north-eastern Victoria was studied during 1988-91. Two indices were used as measures of resistance:
conventional disc-sensitivity tests with culturable bacteria, and the effect of antibiotics on the uptake
of 14C-glucose and 14C-amino acids by native bacterial assemblages. Culturable bacteria were resistant
to ampicillin, methicillin and penicillin but generally sensitive to nalidixic acid, neomycin, streptomycin,
sulfafurazole and tetracycline. Responses to chloramphenicol, erythromycin, nitrofurantoin and
sulfamethizole were variable. Bacteria isolated from rivers were more resistant to antibiotics than were
those isolated from billabongs. Methicillin, even at 200 mg L-1, had little effect on the uptake of
14C-labelled compounds. Nalidic acid (20 mg L-1) also was ineffective unless lengthy pre-incubations
(24 h) were used. Chloramphenicol and tetracycline at 20 mg L-1 markedly reduced amino acid uptake
but not glucose uptake. The widespread antibiotic resistance of aquatic bacteria casts doubt on the
suitability of these compounds to selectively inhibit the prokaryotic component in ecological studies
and may be cause for concern regarding the spread of antibiotic resistance through natural aquatic
communities.
Embryonic and postembryonic development in the Tasman freshwater crayfishes Astacopsis gouldi, Asatcopisis franklinni and Parastacoides tasmanicus tasmanicus (Decapoda : Parastacidae)
Authors: Hamr P
Published: November 2005

The embryonic and postembryonic development of the endemic Tasmanian freshwater crayfishes of the
genera Astacopsis and Parastacoides was studied and described in detail. The embryonic development
was similar in the two genera and corresponded to that described for other Parastacidae and Astacidae,
but a prominent change in the colour of the yolk that parallels embryonic development was also noted.
The general development sequence of young from Stage 1 to Stage 3 in Astacopsis and Parastacoides
is similar to that described for other parastacid, astacid and cambarid crayfishes, but major differences
in development between Astacopsis and other crayfishes are an extra developmental stage as well as the
timing of the development of the uropods. The postembryonic development in Astacopsis is different
from that in other parastacids as well as astaciddcambarids in having retained some of the ancestral
marine larval characters, and it is considered to be primitive. Given this new information, it is proposed
that early development in freshwater crayfishes recapitulates the entire primitive decapod sequence of
larval stages.
Age and growth studies of New Zealand Marine fishes, 1921-90: A review
Authors: Paul LJ
Published: November 2005

The development and use of age and growth studies on New Zealand marine fishes are reviewed.
A summary of studies on 62 species is given. In view of the wide range of approaches and variation
in the level of validation, the studies are not interpreted in detail, but-where available-age at maturity
and maximum recorded age are given. The species for which von Bertalanffy growth parameters are
available are listed, but, because of variation in the quality of results, not the values. The direction
being taken in ageing studies in New Zealand is discussed: age validation, routine ageing of some major
commercial species (leading to modelling), basic age-growth information on little-studied species, and
theoretical studies on fish ageing. A comprehensive bibliography is included.
Fish age validation by Radiometric analysis of Otoliths
Authors: Fenton GE , Short SA
Published: November 2005

Radiochemical analysis of aragonitic fish otoliths provides a useful approach to validating ages obtained
by more common methods. The history of applications of radiometry using short-lived natural isotopes
to clams, Nautilus, living corals and fish otoliths is briefly reviewed. The biogeochemical assumptions
required for successful use of these techniques are discussed, and the appropriate mathematical
treatments required for data analysis are outlined. Novel normalization techniques designed to widen
the validity of this approach are proposed. Desirable lines of further research are also briefly discussed.
Environmental sensitivity of fish Otolith Microchemistry
Authors: Radtke RL , Shafer DJ
Published: November 2005

A considerable aggregate of life-history, environmental and physiological information is incorporated
within fish otoliths. This information may be discerned when appropriate analytical methods, based on
an understanding of the mechanisms underlying changes in the structure and chemistry of otoliths,
are utilized. Deposition of otolith carbonate may be regulated by many interacting factors, including
age, physiology, environmental stress, availability of nourishment, ambient temperature, diurnal and
seasonal cycles, and activity levels of individual fish. Complex interactions between genomic control
and environmental conditions will ultimately govern depositional patterns.
The chemical composition of otoliths is regulated by the physiological activity of fish, which in turn
is influenced by environmental conditions. Interpretation of the chemical patterns in wild fishes must
be validated by analysing the depositional patterns in fishes maintained under experimental conditions.
Microchemistry analyses can provide life-history profiles and data on the environmental history of
individual fish to clarify interpretation of age and growth trajectories. Several factors may contribute
to the reported disparity in elemental studies, including suboptimal rearing environments, thermal effects
on growth rate, and nutritional effects on otolith chemistry. Metabolic data describing growth and
otolith crystallization obtained under artificial conditions that only grossly resemble the subtleties of the
modelled environment may have a limited value and caution should be used when extrapolating results
to natural systems.
Daily incuremtns in Otoliths of juvenile Snapper, Pagrus auratus (Sparidae)
Authors: Francis MP , Williams MW , Pryce AC , Pollard S , Scott SG
Published: November 2005

Sagitta microstructure was investigated in juvenile New Zealand snapper, Pagrus auratus, to provide
a basis for daily ageing in population dynamics studies. Transverse sections produced the clearest daily
increments and were the easiest to prepare. Daily increment formation was validated up to an age
of 100 days by using increment counts from reared juveniles and up to about 160 days by using
changes in mean increment counts from juveniles sampled from a wild population at different times.
A prominent metamorphic mark was visible in transverse and frontal sections, providing a means for
determining the duration of the larval period, and juvenile postmetamorphic ages. Postmetamorphic
increment width varied with the age of the snapper and with season. Increment width dropped below
0.5 μm in winter and increments could not be resolved with a light microscope.
Growth and age validation of Rainbow Trout, Oncorhynchus mykiss (Walbaum)' in Lake Eucumbene, NSW
Authors: Faragher RA
Published: November 2005

Growth rates of finclipped rainbow trout (Oncorhynchus mykiss) released into Lake Eucumbene, New
South Wales, at an age of 0+ years were examined for each year between 1986 and 1988. Traps and
nets yielded significant numbers of marked fish for validation of age estimation and length backcalculation
from scale reading. Poor recognition of the marks by anglers was confirmed, indicating
that survival of the fish was higher than was implied by angling returns. The diffuse nature of the
second annulus in scales provided initial difficulty in ageing, particularly because of a similarly diffuse
false check formed during the second year. Care was required in separating the annuli after asymptotic
growth was reached (3 years), Growth rates in Lake Eucumbene were comparable with those found in
studies in Tasmania and Victoria. Back-calculated lengths were in agreement with those from fish of
known ages. The presence of finclipped fish aged 2 + and 3 + years in a spawning population confirmed
that stocked fish contributed to the spawning stocks. The study reconfirms the importance of validation
of ageing techniques in fisheries investigations.
Validation of Daily Growth increments in Otoliths form Thrysa aestuaria (Ogilby), a tropical Anchovy from Northern Australia
Authors: Hoedt FE
Published: November 2005

Age and growth parameters were determined for the tropical anchovy Thryssa aestuaria from northern
Queensland, Australia. Larval and juvenile forms of T. aestuaria, believed to be a single cohort
recruited in the spring of 1990, were sampled between October 1990 and January 1991. Counts of
growth rings in sagittal otoliths were determined for specimens from three of these samples. Comparisons
of the different ring counts of fish from successive samples with the number of days elapsed
between samples suggested that the growth rings examined were deposited daily. Two specimens of
T. aestuaria marked with tetracycline hydrochloride in aquaria were found to deposit growth rings in
the sagitta at a rate of one ring per day. Problems associated with reading daily growth rings in tropical
anchovies are discussed in light of the results of this study. Growth in T. aestuaria is discussed in
relation to reported growth information for other species of tropical anchovies.
Validation of annual marks in the Otoliths of young Snapper, Pagrus auratus (Sparidae)
Authors: Ferrell DJ , Henry GW , Bell JD , Quartararo N
Published: November 2005

In April 1989, young-of-the-year snapper (Pagrus auratus) were captured from the wild and injected
with tetracycline. The fish were reared on natural food in a large pool with flowing sea water under
ambient marine conditions. Two fish were removed every two months for two years, and the growth
of their otoliths, relative to the tetracycline mark, was measured. Growth of the otoliths was greatest
in spring and summer and least during winter. Opaque marks appeared in the otoliths of fish during
both winters of the study. Our results confirm that the opaque marks in otoliths of young snapper can
be used to determine the age of the fish in years.
Validation of annual growth increments in the Otoliths of two species of Damselfish from the Southern Great Barrier Reef
Authors: Fowler AJ , Doherty PJ
Published: November 2005

If the otoliths of fish are to be used as an ageing tool, they must fulfil three criteria: they must display
an internal structure of increments, this structure must be relatable to a regular time scale, and the
otoliths must grow throughout the lives of the fish at a perceptible rate. These criteria were assessed
for two species of damselfish: Pomacentrus moluccensis and P. wardi from One Tree Reef on the
southern Great Barrier Reef. Transverse sections of sagittae from both species contained an alternating
sequence of opaque and translucent zones that formed an interpretable pattern of increments. Treatment
of fish with tetracycline showed that the opaque zones were formed on an annual basis, generally
between spring and early summer. The assessment of growth of otoliths from fish treated with
tetracycline indicated that those as old as 10 years of age were still laying down increments of regular
thickness. Consequently, the otoliths from both species successfully fulfilled the three criteria required
for the direct determination of age. Furthermore, this study helped to identify two levels of variation
in otolith structure, manifested in the clarity and interpretability of the increments; there was an interspecies
difference and a significant intraspecies latitudinal difference.
Ageing of Adult Snapper (Pagrus auratus) from Otolith annual ring counts: Validation by tagging and Oxytetracycline Injection
Authors: Francis RICC , Paul LJ , Mulligan KP
Published: November 2005

Of 4657 snapper (Pagrus auratus) that were tagged, injected with oxytetracycline (OTC), and released
in 1986-87, 1113 fish were recaptured after periods at liberty from 18 days to 3 years. An OTC mark
was clearly visible in thin sections of all but four of a sample of 125 otoliths. In 90% of the remaining
121 otoliths the position of the OTC mark was correctly inferred from age readings (made without
seeing the OTC mark) based on annual ring counts in otolith sections. It is concluded that the otolith
rings are deposited annually, and estimates are made of error rates in age estimation-both in identifying
annual rings and in interpreting the otolith edge. Further support for the ageing method is
contributed by an analysis of the growth of tagged fish, and by year-to-year consistency in the relative
strength of cohorts. The growth analysis showed a large (more than twofold) interyear variation in
growth rates. Snapper (and other sparid) age estimates based on scale readings may be underestimates.
It is recommended that age validation studies clearly distinguish between three separate factors:
periodicity of marks, identification of marks, and edge interpretation.
Validation of the use of thin-sectioned Otoliths for determining the age and growth of Golden Perch, Macquaria ambigua (Perciformes: Percichthyidae), in the Lower Murray-Darling Basin, Australia
Authors: Anderson JR , Morison AK , Ray DJ
Published: November 2005

Golden perch, Macquaria ambigua, from the Murray-Darling Basin were aged by using transverse thin
sections of their sagittal otoliths. Samples from 889 fish were obtained from riverine and lacustrine
habitats and from wild and stocked populations. Error in the precision of age estimates (calculated as
the mean percentage error of the independent age estimates of four readers) was 5.6% (3.9% after
allowing for discrepancies in relation to the annual mark on the edge of the otolith). Validation was
accomplished by using a combination of analysis of the progression of modes in length-frequency
distributions, qualitative and quantitative marginal-increment analysis, and analysis of age estimates
of fish from populations with a known stocking history. The technique was validated for fish up to
8 years of age (455-545 mm total length, 1695-3988 g total weight), and the greatest recorded age was
16 years (530-600 mm total length, 2607-4050 g total weight). Annual marks become visible in otolith
sections in most fish of all ages in October, and 1 October was designated as the birth date. A
description of our method of reading sections of golden perch otoliths, including recognition of false
annual marks, is given. Otolith length, width and thickness increased linearly with fish length and with
loglo(fish age), whereas otolith weight increased linearly with fish age and exponentially with fish length.
The continuous growth of the otoliths and the consistency in the appearance of annual marks support
the accuracy of estimates up to the maximum recorded age. The mean length-at-age and the parameters
of the length-weight relationship were estimated. The von Bertalanffy growth parameters were also
estimated (L∞ =507 mm, to=0.420 years, K=0.454). No significant differences were found in growth
rates or length-weight relationships between males and females. However, growth (particularly in weight)
was highly variable among sites and years, and slow-growing 5-year-olds may be shorter than fastgrowing
1-year-olds. Ages were estimated for a sample of 86 golden perch caught between 1949 and
1951 but a comparison of growth rates between these and more recent collections was inconclusive.
Growth rate estimates for New Zealand Rig (Mustelus lenticulatus)
Authors: Francis MP , Francis RICC
Published: November 2005

Growth rate estimates were obtained for New Zealand rig (Mustelus lenticulatus) by analysing length
frequency and tag-recapture data. Rig (0+) sampled by set-net in Porirua and Pauatahanui Inlets
grew from about 25-30 cm total length at birth to 46-49 cm at age of about 6 months. Samples of
juvenile and adult rig trawled in Pegasus Bay and Hauraki Gulf suffered from under-representation of
large adults, probably because of escapement. Growth curves derived from length-frequency analysis
indicated that Pegasus Bay males matured at 5.0 years and had a minimum longevity of 12 years.
Hauraki Gulf males and females matured at 3.7 and 4.7 years, respectively. Growth rates and ages at
maturity fell within the ranges reported for other Mustelus species. Tagging data for South Island rig
suggested that females grew faster than males. However, growth rate estimates from length-frequency
analysis were 2.7-3.3 times greater than estimates from tagging data, probably because the latter were
biased by the combined effects of tagging on growth and set-net mesh selectivity.
Estimating growth of the Spiny Lobsters Panulirus cygnus, P.argus and P. ornatus
Authors: Phillips BF , Palmer MJ , Cruz R , Trendall JT
Published: November 2005

Growth in three species of spiny lobster-Panulirus cygnus in Western Australia, P. argus in Cuba,
and P. ornatus in Torres Strait, Australia-was modelled by using nonlinear random-coefficient models.
Approximate confidence intervals about the mean growth curve for carapace length, to include 95%
of the population at any age, have been estimated for these models. For both P. ornatus and P. cygnus,
similar estimates of growth rate were obtained from both laboratory and field studies. Growth of the
two tropical species, P. ornatus and P. argus, was much faster than that of the temperate species
P. cygnus. All three species showed high variability in the growth rates of individuals. Microtagging
of first-moult post-puerulus juveniles of P. cygnus with 1 mm long × 0.25 mm stainless-steel tags
provides the first published field data on the growth of spiny lobsters from the beginning of the benthic
period. These data suggest that tagging or handling can decrease the growth rates of spiny lobsters.
Growth of four species of juvenile fish associated with the Seagrass Zostera capricorni, in Botany Bay, NSW
Authors: Worthington DG , Ferrell DJ , NcNeill SE , Bell JD
Published: November 2005

Populations of four species of juvenile fish- Rhabdosargus sarba, Acanthopagrus australis, Achoerodus
viridis and Girella tricuspidata-were sampled from a seagrass bed in Botany Bay, New South Wales.
Fish were collected eight times between 22 March 1990 and 22 February 1991, using a small seine-net.
Growth rates were calculated from the progression of cohorts in length-frequency distributions.
Cohorts of R. sarba, A. australis and A. viridis grew most slowly during winter (0.02, 0.04 and
0.21 mm day-1, respectively); growth then increased, peaking just prior to the loss of the cohort from
the habitat (0.3 1, 0.24 and 0.39 mm day-1). Populations of R. sarba, A. australis and A. viridis were
comprised of one or two cohorts that remained in the habitat for at least 3-4 months. Conversely, up
to seven cohorts of G. tricuspidata were found between October and February, and most cohorts did
not remain in the habitat for more than 2 months. As a result, there were only two confident estimates
of growth for G. tricuspidata: 0.23 mm day-1 between October and November, and 0.34 mm day-1
between January and February. Individuals of each species were also kept in a flow-through 4000-L
tank of sea water. Growth of cohorts of fish kept in the tank was very similar to that found in natural
populations during the same time period. The rates of recruitment and loss of cohorts from seagrass
can be rapid and these factors must be considered in designing a sampling programme to assess growth
by analysis of length-frequency distributions.
Do Otoliths record changes in somatic growth rate? Conflicting evidence form a laboratory and field study of a temperate Reef Fish, Parika scaber
Authors: Milicich MJ , Choat JH
Published: November 2005

Otolith increment widths in a temperate reef fish, Parika scaber (Pisces:Monacanthidae), have been shown to vary in different months and to correlate with changes in somatic growth rate. This results in the persistence of a constant otolith-size/fish-size relationship. In the present study, the response of otolith growth to laboratory-induced changes in body growth was determined over a 10-day period in December 1985. Juveniles were subjected to two ranges of temperature (19-21�C and 24-26�C) and three feeding levels (fully fed, partially fed, and starved) of a diet consisting of larvae of Opifex fuscus, an endemic mosquito. Fish were individually tagged to ensure that changes in growth rate and any associated changes in otolith microstructure could be accurately determined for any individual. Fully fed fish grew more slowly during treatment than they did prior to treatment, and starved fish did not grow at all. Partially fed fish exhibited a size-hierarchy effect, with larger fish increasing in body size at the expense of smaller individuals. No temperature effect on growth rate was recorded. In contrast to the results from an associated field study, otoliths of fully fed fish continued to increase at the same daily width despite the induced alteration in growth rate. Thus, otoliths were disproportionately large compared with estimates from the field. However, otoliths of starved fish were not as large as predicted from a continual production of daily rings at a constant width. Daily ring deposition may have ceased at different times during the experiment for the starved fish, depending on body size. Alternatively, deposition may have continued, but at a spacing that was not detectable by light microscopy. We conclude that adequate validation of response of otolith growth to changes in somatic growth is necessary before individual growth histories can be back-calculated. This is true even where strong evidence from the field suggests that back-calculation is possible.
Age and growth studies of Gummy Shark, Mustelus antarcticus Gunther, and School Shark, Galeorhinus galeus (Linnaeus), from Souther Australian Waters
Authors: Moulton PL , Walker TI , Saddlier SR
Published: November 2005

Age-length data were derived from counting stained bands on whole vertebral centra obtained from gummy shark, Mustelus antarcticus, captured by gill-nets during 1973-76 in Bass Strait and from gummy shark and school shark, Galeorhinus galeus, captured during 1986-87 in Bass Strait and waters off South Australia. The data were fitted to the von Bertalanffy growth equation after adopting the Francis reparametrization and correcting for sampling bias caused by the selectivity effects of the gill-nets of various mesh sizes used to capture the sharks. The von Bertalanffy growth curves of male and female gummy shark were significantly different, but the growth curves of male and female school shark were not. The growth curves suggest that growth rates of male and female gummy shark in Bass Strait were lower during 1986-87 than during 1973-76 and that the growth rates of male and female gummy shark and school shark in Bass Strait during 1986-87 were lower than those in South Australia at the same time. These apparent temporal and spatial differences in growth patterns of gummy shark are explained by the 'Phenomenon of Apparent Change in Growth Rate'. It is concluded that the growth curves determined for 1986-87 are distorted by the effects of a long history of high and length-selective fishing mortality and that actual growth patterns of gummy shark are better represented by the von Bertalanffy growth equation determined for shark caught in Bass Strait during 1973-76, when fishing mortality was much lower. Verification of age estimates was attempted by comparing von Bertalanffy growth curves derived from age-length data with those derived from tag release-recapture length-increment data, but these comparisons highlight the limitations of using tag data for this purpose. Although reasonable agreement was found between such growth curves for gummy shark, it appears that school shark older than 11 years cannot be aged accurately from stained whole or sectioned vertebrae. Sectioned vertebrae from a school shark recaptured 35.7 years after being tagged and released and calculated as having an age exceeding 45 years gave estimates of only 18-20 years of age.
Age and growth of the narrow-barred Spanish Mackerel (Scomberomorus commerson Lacepede, 1880) in North-eastern Queensland waters
Authors: McPherson GR
Published: November 2005

Whole otoliths were used to age Scomberomorus commerson in tropical Australian waters. Age estimates were validated by marginal-increment analysis of the first three otolith annuli. Confirmation of age estimates was provided by otolith daily growth increments and tag returns of known age. Differential growth in length, weight and longevity was evident between the sexes. The oldest male was 10 years old (127 cm FL, 19.0 kg). The oldest female was 14 years old (155 cm FL, 35 kg). The von Bertalanffy growth parameters L∞ and K were 127.5 cm and 0.25 for males and 155.0 cm and 0.17 for females.
Age, growth and mortality of the Inshore Coarl Trout Plectropomus maculatus (Pisces: Serranidae) from the Central Great Barrier Reef, Australia
Authors: Ferrira BP , Russ GR
Published: November 2005

Age and growth of the inshore coral trout P. maculatus from the central Great Barrier Reef region was determined by studies of annuli in whole and sectioned sagittae. The periodicity of formation of the annulus was validated through tetracycline labelling of mark-recaptured fishes in the wild and of captive fishes in aquaria. Results obtained from three recaptured and five captive fishes showed that annuli are formed once a year during late winter and spring months. von Bertalanffy growth-curve parameters were L∞ = 60.00 cm SL, K= 0.206 and to = - 0.945 year. The oldest specimen examined was a 12-year-old male of 58 cm SL. The total rate of mortality (Z) was estimated to be 0.569.