Analysis Of Growth Increments Research Articles

Inferring individual marine migration from otolith ecogeochemical signatures of a wide-ranging fish

Despite technical advances in archival tag attachment and functional longevity, long-term tracking of individuals of some fish species remains prohibitively difficult. Here we combined high resolution stable isotope sampling of otoliths, genetic assignment, growth increment analyses and a simple movement model to inform a hidden Markov model of the location of individual wild Atlantic salmon (Salmo salar L.) at sea. The model provided a reconstruction of North Atlantic migration for a species which is extremely difficult to track throughout its marine life-stage. We show that plausible emigration and return migration patterns can be achieved from wild fish. Simulations of simplified northward and westward movement patterns in the North Atlantic were used to quantify precision and accuracy of the model which differed between these two directional scenarios. Because otolith-derived migratory information does not rely on capture, release and subsequent recapture of the individual, this can be retrieved from any fish. Thus these techniques offer a powerful tool for improving our understanding of the processes that govern movement and survival of individual fish during a protracted and largely unobservable life-stage in the oceanic environment.

Potential sources of bias in the climate sensitivities of fish otolith biochronologies

Analysis of growth increments in the hard parts of animals (e.g., fish otoliths) can be used to assess how organisms respond to variability in environmental conditions. In this study, mixed-effects models were applied to otolith data simulated for two hypothetical fish populations with assumed biological parameters and known growth response to environmental variability. Our objective was to assess the sensitivity of environment–growth relationships derived from otolith biochronologies when challenged with a range of realistic ageing errors and sampling regimes. We found that the development of a robust biochronology and the precision of environmental effect estimates can be seriously hampered by insufficient sample size. Moreover, the introduction of even moderate ageing error into the data can cause substantial underestimation of environmental sources of growth variation. This underestimation diminished our capacity to correctly quantify the known environment–growth relationship and more generally will lead to overly conservative conclusions concerning the growth response to environmental change. Careful study design, reduction of ageing errors, and large sample sizes are critical prerequisites if robust inferences are to be made from biochronological data.

Facultative amphidromy and pelagic larval duration plasticity of Rhinogobius formosanus (Teleostei, Gobioidei)

Rhinogobius formosanus Oshima, 1919 has long been considered an amphidromous goby. However, a landlocked population recently found in the Jingualiao Creek upstream of the Feitsui Reservoir in Taipei suggests that R. formosanus may complete its life in the river. This study aims to verify the habitat use of the landlocked population of R. formosanus collected from the Feitsui Reservoir and an amphidromous population collected in Malian Creek using otolith Sr:Ca ratio analysis. The hypothesis that early life history varies between the landlocked and migratory gobies was also tested. Genetic analyses show that the Feitsui Reservoir and Malian Creek populations are not genetically different. Rhinogobius formosanus from Malian Creek showed high-to-low otolith Sr:Ca ratios suggesting that these specimens spent a planktonic larval stage in the sea followed by a freshwater life at later stages. In contrast, R. formosanus from the Feitsui Reservoir showed constant lower otolith Sr:Ca ratios, implying a landlocked life history of fish in the creek upstream of the reservoir. In addition, the analysis of growth increments showed a longer pelagic larval duration for the fish in the Malian Creek (58.8 days) than those in the Feitsui Reservoir (38.8). Variation of pelagic larval duration in two genetically homogenous populations implies acclimatization to the reservoir by the landlocked gobies. This study shows that R. formosanus, like some other congeners, is capable of adapting to a freshwater landlocked environment in its early developmental stage and supports the hypothesis that landlocked populations may have a shorter pelagic larval duration.

New insights into oyster high-resolution hinge growth patterns

While oyster shells are one of the most common mollusks used for the analysis of (paleo)environmental and (paleo)climatic records based on geochemical proxies, high-resolution growth rate changes still need to be determined. Promising previous works are restricted to small portions of shell sections due to difficulties in continuous growth increment revelation. Based on a mark and recapture experiment of Magallana gigas specimens reared in an intertidal area of Normandy (France) for 22 months, and a sclerochronological approach using cathodoluminescence microscopy, this study provides the longest high-resolution record of growth increments in oyster shells to date. Different growth patterns were identified likely related to the oyster age. After age 1 year, the formation of growth increments follows an expected tide-related model, leading to the mineralization of ~ 2 calcitic increments per day, together with growth rate changes at lunar and semi-lunar periodicities, and a seasonal trend with occasional growth breaks during winter when temperatures fall below ~ 6 °C. However, for oysters younger than 1 year, i.e., before reaching their sexual maturity, the growth increment analysis reveals unconventional patterns. In this case, oysters’ growth is associated with either a large number (~ 5) or less than one increment per day depending on the period. This pattern is also associated with frequent growth cessations, although the growth rate of the shell is high at this period. Our results illustrate that the high-resolution sclerochronological approach is required for accurate paleoenvironmental reconstructions based on oyster shells.

Reconstructing larval growth and habitat use in an amphidromous goby using otolith increments and microchemistry.

High-resolution analysis of growth increments, trace element chemistry and oxygen isotope ratios (δ18 O) in otoliths were combined to assess larval and post-larval habitat use and growth of Awaous stamineus, an amphidromous goby native to Hawai'i. Otolith increment widths indicate that all individuals experience a brief period of rapid growth during early life as larvae and that the duration of this growth anomaly is negatively correlated with larval duration. A protracted high-growth period early in larval life is associated with a lower ratio of Sr:Ca, which may reflect low salinity conditions in nearshore habitats. A distinct shift in δ18 O (range: 4-5‰) is closely associated with the metamorphic mark in otoliths, indicating that larval metamorphosis occurs promptly upon return to fresh water. Strontium and other trace elements are not as tightly coupled to the metamorphosis mark, but confirm the marine-to-freshwater transition. Integration of microstructural and microchemical approaches reveals that larvae vary substantially in growth rate, possibly in association with habitat differences. Although time and financial costs make it difficult to achieve large sample sizes, present results show that examining even a small number of individuals can lead to novel inferences about early life history in diadromous fishes and illustrates the value of integrating analyses.

Determination of squid age using upper beak rostrum sections: technique improvement and comparison with the statolith

Analysis of growth increments in beak rostrum sagittal sections (RSSs) has been increasingly used for estimating octopus age. In this study, we develop an effective method to process and read the RSS of four oceanic ommastrephid squid species (Dosidicus gigas, Ommastrephes bartramii, Illex argentinus and Sthenoteuthis oualaniensis) and validate the daily deposition of the increments by comparing to corresponding statolith-determined ages. The proposed method of processing yielded readable rates ranging from 42.9 % in I. argentinus to 71.7 % in D. gigas for samples from I. argentinus to D. gigas. The high precision of the increment readings with low independent counting coefficient of variation indicates that the processing and counting methods used are reliable. This study suggests that the RSS of the upper beak is an appropriate tool for estimating the age of D. gigas, O. bartramii and perhaps S. oualaniensis, although erosion of the rostral region may result in an underestimation of squid ages.

Modelling growth in tuna RFMO stock assessments: Current approaches and challenges

We review the approaches used to model growth in recent tuna Regional Fisheries Management Organization (tRFMO) stock assessments, and the challenges encountered. The tRFMO fisheries span vast areas, with multinational fleets operating a diverse range of gear types, and are assessed with a range of modelling methods. Despite the high volume and/or value nature of many tuna and billfish fisheries, there remain substantial data input challenges, including biased size composition sampling, conflicting age estimates from hard parts (and inconclusive validation studies), and very high error rates in some large-scale tagging programmes. There is evidence for spatial and temporal variability in growth rates, but sampling is rarely adequate to quantify this variability, and it is not described in most tRFMO assessments. Sophisticated statistical methods have been developed to combine catch length frequency distributions, age-length data and tag growth increment observations into a single estimation framework (though the data are generally not sufficient to allow the variances to be objectively partitioned). Modelling individual growth variability with random effects has the potential to greatly reduce biases from tag growth increment analyses, but this is computationally prohibitive when the growth curve is estimated within the assessment model. In contrast, the effects of size-based selectivity may not be adequately described if growth is estimated outside of the assessment model. Different species are affected by these problems to different and largely unknown degrees. We discuss options for mitigating some of these problems, but doubt that entirely satisfactory solutions can be achieved in most cases. Accordingly, we recommend that i) greater emphasis should be placed on representing the plausible growth uncertainty in the assessments (i.e. using a model ensemble approach), and ii) management strategy evaluation should be used to develop harvest strategies that are robust to the growth (and other, potentially more urgent) uncertainties, and to prioritize research investment in the context of achieving management objectives.

Of Travertine and Time: Otolith Chemistry and Microstructure Detect Provenance and Demography of Endangered Humpback Chub in Grand Canyon, USA

We developed a geochemical atlas of the Colorado River in Grand Canyon and in its tributary, the Little Colorado River, and used it to identify provenance and habitat use by Federally Endangered humpback chub, Gila cypha. Carbon stable isotope ratios (δ13C) discriminate best between the two rivers, but fine scale analysis in otoliths requires rare, expensive instrumentation. We therefore correlated other tracers (SrSr, Ba, and Se in ratio to Ca) to δ13C that are easier to quantify in otoliths with other microchemical techniques. Although the Little Colorado River’s water chemistry varies with major storm events, at base flow or near base flow (conditions occurring 84% of the time in our study) its chemistry differs sufficiently from the mainstem to discriminate one from the other. Additionally, when fish egress from the natal Little Colorado River to the mainstem, they encounter cold water which causes the otolith daily growth increments to decrease in size markedly. Combining otolith growth increment analysis and microchemistry permitted estimation of size and age at first egress; size at first birthday was also estimated. Emigrants < 1 year old averaged 51.2 ± 4.4 (SE) days and 35.5 ± 3.6 mm at egress; older fish that had recruited to the population averaged 100 ± 7.8 days old and 51.0 ± 2.2 mm at egress, suggesting that larger, older emigrants recruit better. Back-calculated size at age 1 was unimodal and large (78.2 ± 3.3 mm) in Little Colorado caught fish but was bimodally distributed in Colorado mainstem caught fish (49.9 ± 3.6 and 79 ± 4.9 mm) suggesting that humpback chub can also rear in the mainstem. The study demonstrates the coupled usage of the two rivers by this fish and highlights the need to consider both rivers when making management decisions for humpback chub recovery.

Seasonality and Intensity of Shellfish Harvesting on the North Coast of British Columbia

ABSTRACT Biogeochemical and growth increment analyses show contrasting seasonal patterns of butter clam collection and rates of harvest intensity between archaeological shell midden sites from the Dundas Islands archipelago and the mainland coast in Prince Rupert Harbour, northern British Columbia. Growth increment analysis shows more intensive clam harvest in the Dundas Islands in comparison to the residential sites in Prince Rupert Harbour. Stable oxygen isotope analysis shows multi-seasonal collection of clams in the Dundas Islands and a more seasonally specific emphasis in Prince Rupert Harbour. Comparison of these results to those of similar studies in the Namu region on the central coast of British Columbia provides a basis for broader regional understanding of variation in shellfish harvesting intensity and seasonality on the Pacific Northwest Coast.

Sea ice extent and seasonality for the Early Pliocene northern Weddell Sea

Growth increment analysis coupled with stable isotopic data ( δ 18O/ δ 13C) from Early Pliocene (ca 4.7 Ma) Austrochlamys anderssoni from shallow marine sediments of the Cockburn Island Formation, northern Antarctic Peninsula, suggest these bivalves grew through much of the year, even during the coldest parts of winter recorded in the shells. The high frequency fluctuation in growth increment width of A. anderssoni appears to reflect periodic, but year-round, agitation of the water column enhancing benthic food supply from organic detritus. This suggests that Austrochlamys favoured waters that were largely sea ice free. Our data support interpretation of the Cockburn Island Formation as an interglacial marine deposit and the previous hypothesis that Austrochlamys retreated from the Antarctic as sea ice extent expanded, this transition occurring during climate cooling in the Late Pliocene.

Shell growth history of geoduck clam (Panopea abrupta) in Parry Passage, British Columbia, Canada: Temporal variation in annuli and the Pacific Decadal Oscillation

An assemblage of geoduck clam shells from the marine environment of coastal British Columbia was studied. Shells were cut and the widths of internal shell growth increments, annuli, were measured from the hinge plate. The largest shells showed more than one hundred annual increments. Shell growth exhibited juvenile maxima at ontogenetic ages 3–6 years. The growth maximum was followed by a distinct decline that continued until the death of each individual. Further, this ontogenetic growth trend was mathematically removed from the data in order to examine growth variations other than ageing. The longest growth records from the oldest shells were compared to monthly indices of the Pacific Decadal Oscillation (PDO). It was found that the PDO exerts the strongest influence on the shell growth during the very start of the growing season, in February and March. We also detected increased magnitude of growth variations towards the end of the 20th century. Similar trends were apparent in the PDO record. Moreover, the shell specimen displaying the strongest trend of increasing variance had the strongest PDO-linked regional growth signal. Our results support the view that PDO exerts a governing influence on the biological and ecological system along Northeast Pacific coastal areas. Incorporation of geoduck shell growth increment analyses into multi-disciplinary studies dealing with palaeoceanography and archaeology is suggested as a promising future approach.

Recruitment of the amphidromous goby Sicyopterus japonicus to the estuary of the Ota River, Wakayama, Japan

Ecological aspects of recruitment in the amphidromous goby, Sicyopterus japonicus, were studied from larval collections made with a set net in the estuary of the Ota River, Wakayama, Japan. The abundance patterns of the 12,766 larvae collected from 18 April to 26 August 2006 showed several peaks during the recruitment season. Their body sizes at recruitment ranged from 23.5 to 30.0 mm standard length (mean ± SD, 26.3 ± 1.1 mm), 0.11 to 0.49 g body weight (0.22 ± 0.05 g), and 8 to 20 condition factor (11 ± 2). The standard length of the goby larvae tended to decrease with the season, while their body weight slightly increased and resulted in an increase in condition factor. The recruitment of larvae occurred mainly during the daytime. Otolith growth increment analysis of 30 larvae collected by a square lift net on 30 April 2005 revealed that the oceanic larval duration after downstream migration ranged from 173 to 253 days (208 ± 22) after hatching. A limited time of recruitment in early summer and a considerably long duration of oceanic life (about a half year) appeared to be unique characteristics of this Sicyopterus species that lives in a temperate region in comparison to other tropical species of the genus Sicyopterus that all have year-round recruitment.

Coupled North Atlantic slope water forcing on Gulf of Maine temperatures over the past millennium

To investigate ocean variability during the last millennium in the Western Gulf of Maine (GOM), we collected a 142-year-old living bivalve (Arctica islandica L.) in 2004, and three fossil A. islandica shells (calibrated 14CAMS = 1030 ± 78 ad; 1320 ± 45 ad; 1357 ± 40 ad) for stable isotope and growth increment analysis. A statistically significant relationship exists between modern GOM temperature records [shell isotope-derived (30 m) (r = −0.79; P < 0.007), Prince 5 (50 m) (r = −0.72; P < 0.019), Boothbay Harbor SST (r = −0.76; P < 0.011)], and Labrador Current (LC) transport data from the Eastern Newfoundland Slope during 1993–2003. In all cases, as LC transport increased, GOM water temperatures decreased the following year. Decadal trends in the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO) influence GOM water temperatures in the most recent period, with water temperatures decreasing during NAO and AMO negative modes most likely linked to LC transport and Gulf Stream interaction. Mean shell-derived isotopic changes (δ18Oc) during the last 1,000 years were +0.47‰ and likely reflect a 1–2°C cooling from 1000 ad to present. Based on these results, we suggest that observed cooling in the GOM during the last millennium was due to increased transport and/or cooling of the LC, and decreased Gulf Stream influence on the GOM.

EVOLUTION OF PREHISTORIC FISHING IN THE NILE VALLEY

The available data are reviewed on ichthyofaunas from prehistoric sites along the Nile in Egypt and Sudanese Nubia. Former fishing practices are reconstructed using information derived from species spectra, reconstructed fish sizes, growth increment analysis and fishing implements. It is demonstrated that fishing was initially practised exclusively on the floodplain and that it was limited to a small number of shallow water taxa during Late Palaeolithic times. From the Epipalaeolithic onwards (ca 10000-8000 bp), fishing was also undertaken in the main Nile whereby the number of exploited species increased. Technological innovations allowing the exploitation of the deeper parts of the main river included nets and fish-hooks as well as improved vessels, permitting the capture of larger species from the open water. It is argued that fish must always have been a staple food because the animals seasonally occurring in large numbers on the floodplain were intensively exploited and because these fish could be easily dried for future consumption. Once the fishing grounds also included the main river, fishing was no longer restricted to the flood season, but could also be carried out when the Nile levels were low. Hence the role of fish in the resource scheduling also changed at the transition of Late Palaeolithic to Epipalaeolithic times.

Upstream dams and downstream clams: growth rates of bivalve mollusks unveil impact of river management on estuarine ecosystems (Colorado River Delta, Mexico)

We studied how the extensive diversion of Colorado River water, induced by dams and agricultural activities of the last 70 years, affected the growth rates of two abundant bivalve mollusk species ( Chione cortezi and Chione fluctifraga) in the northern Gulf of California. Shells alive on the delta today (‘Post-dam’ shells) grow 5.8–27.9% faster than shells alive prior to the construction of dams (‘Pre-dam’ shells). This increase in annual shell production is linked to the currently sharply reduced freshwater influx to the Colorado River estuary. Before the upstream river management, lower salinity retarded growth rates in these bivalves. Intra-annual growth rates were 50% lower during spring and early summer, when river flow was at its maximum. Growth rates in Chione today are largely controlled by temperature and nutrients; prior to the construction of dams and the diversion of the Colorado River flow, seasonal changes in salinity played an important role in regulating calcification rates. Our study employs sclerochronological (growth increment analysis) and geochemical techniques to assess the impact of reduced freshwater influx on bivalve growth rates in the Colorado River estuary. A combination of both techniques provides an excellent tool to evaluate the impact of river management in areas where no pre-impact studies were made.

δ13C of fluvial mollusk shells (Rhône River): A proxy for dissolved inorganic carbon?

The relationship between the δ13C of dissolved inorganic carbon (DIC) and modern mollusk aragonite from rivers was calibrated for the purpose of reconstructing DIC paleochemistry from the shell record. The δ13C values of aragonitic bivalves (Dreissena polymorpha, Corbicula fluminea), prosobranch gastropods (Bithynia tentaculata, Theodoxus fluviatilis, Viviparus viviparus), and an air‐breathing pulmonate gastropod (Limnea auricularia) were analyzed from several locations on the Rhône River (—13.7‰ to —6.0‰) and its major tributary, the Saône River (—11.4‰ to —10.2‰). The δ13CDIC varied from —11.5‰ to —7.5‰, and the δ13C of particulate inorganic matter (POM) varied from —31.7‰ to —25.4‰. At a given site, the δ13C of all species except the pulmonate were within 1‰ of each other. Whole‐shell δ13C correlated positively with δ13CDIC, with a slope close to unity. Bioaragonite—DIC fractionations were 0–1.5‰ for bivalves and 0–2.7‰ for gastropods (excluding the pulmonates). Applying these fractionations, bivalves that live in open water are a reliable proxy, monitoring the average δ13CDIC value to within its natural ~2‰ temporal variation within the growth period. For the suspension feeders (bivalves) using POM as a food source, the δ13C of whole shells and bulk POM indicated that the incorporation of carbon derived from respiratory sources lay in the range 10–30%. Fine‐scale analyses of growth increments of C. fluminea could not be related simply to δ13CDIC because metabolic and seasonal variations in δ13CDIC produced similar isotopic fluctuations (≤2.5‰).

Convergent growth regulation in arthropods: biological fact or statistical artifact?

Convergent growth regulation, where individuals adjust their growth trajectories to reach a targeted final body size, has been reported for many arthropod taxa. Divergent growth, where larger individuals grow proportionately more than smaller individuals, is seldom observed. Most studies based their conclusions on growth increment analysis: correlation or regression between body size at a particular molt and the increment grown during the next molt. These studies interpreted a negative relationship as evidence for convergent growth regulation, since smaller individuals appeared to grow more during the subsequent molt than larger individuals. Using random data simulations and an analysis of the statistics, I demonstrate that autocorrelation in these statistics generates false evidence for convergent growth, even when divergent growth actually occurred. I suggest model II geometric mean (GM) regression as an alternative method because it does not suffer from these statistical problems. A GM regression reanalysis of two published studies revealed evidence for divergent growth or no growth regulation in cases where the original studies reported convergent growth regulation, suggesting that the reported prevalence of convergent growth may be a statistical artifact.

Reconstructing age distribution, season of capture and growth rate of fish from archaeological sites based on otoliths and vertebrae

The growth increments of otoliths and vertebrae of plaice (Pleuronectes platessa) derived from a 15th century single depositional event at Raversijde (Belgium) are analysed with the aim of reconstructing (a) the age distribution of the population, (b) the season of capture, and (c) the growth rate. Otoliths and vertebrae give slightly different age distributions but it is possible to arrive at similar seasonality estimations in both structures when information from the literature and our own date from monthly captures of plaice from the North Sea are taken into account. These modern data show that the timing of annulus formation in otoliths and vertebrae is more or less similar. Back-calculations on vertebrae and otoliths yield similar growth curves. The age distribution, the edge condition of both vertebrae and otoliths, and the growth rate obtained on the material from Raversijde all show that the plaice from the studied assemblage were captured during spring in the southern part of the North Sea. Vertebrae are commonly preserved in archaeological sites whereas otoliths rarely survive. Although they are more difficult to read than otoliths, vertebrae of plaice can be used for growth increment analyses, and the growth rates obtained from vertebrae from archaeological sites can, therefore, be compared in the future to growth data from modern otoliths studied in sea fisheries research. Archaeozoological material predating industrialized fishing since the 19th century can hence serve as a reference in the study of the compensatory response of commercially important species to heavy exploitation. Copyright

INDIVIDUAL VARIATION OF ONTOGENIES: A LONGITUDINAL STUDY OF GROWTH AND TIMING.

This study of growth and developmental time in the water strider Limnoporus canaliculatus (Heteroptera: Gerridae) is based on longitudinal data from specimens reared individually in the laboratory. I analyzed multivariate allometry using a common principal components approach. This technique identified patterns of variation that were uncorrelated both within and among instars and which remained fairly constant throughout the growth period; in contrast, the overall amount of variation increased from young to older instars. Negative correlations between size and subsequent growth increments indicated convergent growth in the first three instars, but there was a transition to positive correlations (divergent growth) in later instars. Analysis of covariation among measurements made in different instars showed strong ontogenetic autocorrelation and revealed patterns remarkably similar to those found in mammals and birds; yet corresponding analyses of growth increments showed mainly independent variation in different instars. Therefore, I conclude that the strong correlations among stage-specific measurements result from the part-whole relationships inherent to these cumulative size data, but do not reflect specific properties of the organisms studied. In contrast to size increments, instar durations of water striders were highly correlated throughout the larval period, indicating that individuals tended to develop at either relatively fast or relatively slow rates in all instars. The correlations between growth increments and instar durations were nil or negative, contrary to expectations from life-history theory. The results of these analyses of individual variation match the findings from other water striders and from interspecific comparisons in the genus Limnoporus, but information about physiological mechanisms of molting and growth in insects cannot completely explain the patterns observed.

Oxygen and carbon isotope composition of Quaternary bivalve shells as a water mass indicator: Last interglacial and Holocene, East Greenland

Oxygen and carbon isotope composition of arctic bivalve shells are used in an attempt to reconstruct surface water temperature and salinities in Scoresby Sund, East Greenland. The oxygen isotope compositions of Mya truncata, Hiatella arctica and Tridonta borealis have been compared with present day hydrological parameters. Modern shells yield oxygen isotope values that, on the whole, reproduce the environmental temperature and sea water isotopic composition. Furthermore, it is possible to estimate the living depth of the analysed specimens. Analyses of growth increments from single shells show that there are large variations from year to year in temperature and oxygen isotope composition of the surface waters of Scoresby Sund and that these variations decrease with depth. Analyses of Holocene shells indicate that the Polar Current water, which flows from north to south along the East Greenland coast was also present during the Holocene climatic optimum 8000-7000 yr B.P. Analyses of bivalve shells from the last interglacial show that Scoresby Sund during that time was well circulated and that meltwater from the Greenland ice sheet and sea ice meltwater was important for the temperature, salinity and isotopic composition of the surface waters.