Number Of Growth Increments Research Articles

Age validation in early stages of Sepia officinalis from beak microstructure

This is the first study addressing validation of the early growth stages (including the first increment) in the beaks of juvenile cuttlefishes. The age validation in juveniles of Sepia officinalis was performed by comparison of the number of increments observed in the rostrum surface of lower jaws with their true age. A total of 159 individuals were reared at 18 ºC and 21 ºC, with ages up to 31 days from hatching. The number of growth increments in the beak was counted and contrasted with the days of life after hatching, validating the hypothesis of one increment of growth corresponding to one day of life. The mean coefficient of variation between readings (measuring precision) was 2.95 ± 5.98%. The growth of the reading area (rostrum surface) and the periodicity of increment deposition showed no difference between the two culture temperatures and therefore daily deposition was confirmed at these temperatures.

Effect of food availability on the growth and age determination of European sardine (Sardina pilchardus Walbaum, 1792) larvae

AbstractAccurate assessment of age and growth of fish is essential to understand population dynamics, namely for age-structured stock assessment and for determining vital rates of fish (e.g. age at sexual maturity) and their relationship with environmental variability. To validate the daily deposition in the otoliths of European sardine (Sardina pilchardus) larvae, these were reared with a range of food densities translating into feeding rates extending from less than required for maintenance to saturated feeding levels. When exogenous feeding began, a high variability in the relationship between number of growth increments (GI) and elapsed days after hatching (dph) was observed, irrespective of the feeding treatment. GI counts using a light microscope were less than one per day for larvae <15 dph (ranging from 0.17–0.43 GI day−1) and similar for larvae reared with different food concentrations. The rate of GI count vs age was significantly higher for larvae older than 15 dph. GI count from 3–30 dph was lower than one per day (0.45–0.75 GI day−1 95% CI) for fed larvae 3–30 dph. Scanning electron microscopy confirmed the daily deposition of GI and revealed some increment widths around 0.2 μm, particularly during the first week post-hatch. Otoliths of wild sardine larvae exhibited narrow GI (<0.5 μm) comparable with reared larvae. This study demonstrates that during the first weeks after hatch the daily increment deposition is underestimated using traditional light microscopy, which must be taken into account in future works determining wild sardine larval growth.

Life history traits of the deep-sea pelagic cephalopods Japetella diaphana and Vampyroteuthis infernalis

The pelagic cephalopods Japetella diaphana and Vampyroteuthis infernalis are charismatic and widely distributed members of deep pelagic ecosystems. Their habitat temperatures, metabolic rates, feeding and reproductive strategies all together suggest that the pace of life in these species is reduced when compared to neritic octopod species, but information on longevity, growth rates and age estimations are absent to date. To estimate the pace of life in pelagic octopods, this study investigated size at maturity, reproductive strategy, and the number of growth-increments in the upper beak lateral walls (LWS) of J. diaphana (an octopod) and V. infernalis (a vampyromorph). Daily deposition of growth increments in hard body structures (e.g., beaks and stylets) has been validated experimentally in some temperate and tropical octopods, but remains unquantified and not yet validated for most deep-sea and high-latitude cephalopods. We used a diverse assemblage of specimens ranging from early juveniles to adults for both species. Mature J. diaphana had a mantle length (ML) of 53–144 mm and a body mass (BM) of 18–235 g. A brooding female of J. diaphana captured at 1352 m in the Gulf of California was carrying 1419 eggs in pre-organogenetic stage that measured ~2.5 mm in diameter. The size range of mature V. infernalis was ML 66–122 mm and BM 34–286 g. The number of growth increments in the beaks ranged from 21 to 207 in J. diaphana and from 89 to 375 in V. infernalis. If the growth increments are formed daily, like in tropical octopod species, age estimates are incongruent with the low metabolic rates and reproductive strategies of the two species. These observations suggest that growth increments may require more than one day to be formed. To better understand the life histories of invertebrates in the largest but least studied habitat on the planet, age and growth validation studies are critical.

Microstructure comparison of hard tissues (statoliths, beaks, and eye lenses) of Uroteuthis chinensis in the South China Sea

In the present study, the microstructure features and the number of growth increments in the statoliths, beaks, and eye lenses of the mitre squid, Uroteuthis chinensis (Gray, 1849), were examined. Growth increments in three regions of the statolith [the dorsal dome (SDD), lateral dome (SLD), and rostrum] were observed; those of the SLD had the most stable increment widths. The SLD and SDD had a similar number of growth increments. Increment number in the rostrum sagittal section (RSS) of the upper beak was lower (about 30 increments) and that of the eye lens was many times higher (about 3–5 times) than those in the statolith and the beak. The best fits against mantle length were the number of growth increments of the beak, SLD, and eye lens. The relationship between mantle length and growth increments of SLD could be described with two separate equations, possibly indicating that two different cohorts were sampled. Based on the growth increments of SLD, the maximum age of U. chinensis in our study was inferred to be 169 d.

Comparative growth increments of gladius surface and cross-sections to estimate Sthenoteuthis oualaniensis age

The age of the purpleback flying squid (Sthenoteuthis oualaniensis) has been widely studied over its geographic range based on hard structure analysis, especially the statolith. In this study, we propose an additional method for estimating the age of S. oualaniensis using growth increments in the gladius. Our results show regular growth increments in the proostracum dorsal surface and stem cross-sections. Linear regression analysis of the relationship between statolith and gladius readings showed the formation of increments in stem cross-sections to be daily, assuming that the formation of increments is daily in statoliths. A progressively more faint microstructure in the half-posterior part of the gladius possibly explains why the number of growth increments in the proostracum dorsal surface is less than the statolith-determined age. The low average percentage error and coefficient of variation indicate that our modified processing and counting methods are reliable. We believe that using growth increments in the gladius stem cross-section is a feasible alternative tool for determining the age of S. oualaniensis, whereas using growth increments in the proostracum dorsal surface is more informative for reconstructing ontogenetic life history.

Morphometry and growth of sea pen species from dense habitats in the Gulf of St. Lawrence, eastern Canada

ABSTRACTWe examined four species of sea pen (Anthoptilum grandiflorum, Halipteris finmarchica, Pennatula aculeata and Pennatula grandis) collected from the Gulf of St. Lawrence and mouth of the Laurentian Channel, eastern Canada. An exponential length–weight relationship was found for all four species, where growth in weight was progressively greater than growth in length with increasing colony size. Halipteris finmarchica, P. grandis and P. aculeata presented the better allometric fits, explaining over 80% of the variance. In addition, a count of growth increments visible in transverse sections in 86 A. grandiflorum and 80 P. aculeata samples was made. Presumed ages ranged between 5 and 28 years for A. grandiflorum and 2 and 21 years for P. aculeata. Radiocarbon assays were inconclusive and could not be used to confirm these ages; further age validation is required. Radial growth of the rod is slow during the first years, increasing at intermediate sizes of the colony and slowing down again for large colonies. Similar results were obtained from the relationship between colony length and number of growth increments where a logistic model was the best fit to the data. On average Spearman’s rank correlations showed 11% of shared variance between sea pen length or weight and environmental variables. Bottom temperature and salinity, depth and summer primary production were significantly correlated to sea pen size for most species.

Larval stage duration, age and growth of blue lanternfish Tarletonbeania crenularis (Jordan and Gilbert, 1880) derived from otolith microstructure

Tarletonbeania crenularis specimens were collected off Oregon in 2006 and 2009 and aged by enumeration of growth increments in otoliths (sagittae). Three microstructural zones were evident in the otoliths of juvenile and adult fish: central, middle, and external. The number of increments in the central zone are thought to be deposited during the larval phase which is restricted to the uppermost 350 m water layer. The middle zone constituted of barely visible increments, most likely represented a non-migratory behavior of transforming larvae and early juvenile stages. Well defined growth increments were found in the external zone which was presumably formed during extensive vertical migrations of juvenile and adult fish. If the enumerated increments were deposited daily, as previously validated for other myctophid species, the examined individuals indicated a shorter life span than has been formerly reported on the basis of length frequency analysis. The otolith microstructure interpretation was supported by otolith size to fish length proportions and somatic growth of larvae and postlarval fish. Otolith length to standard length relation was described by linear regression models for larvae and postlarval migratory stages with an abrupt disruption between these two groups. The number of growth increments in otoliths plotted against standard length showed a curvilinear growth for larvae and for the postlarval fish. The lack of information on the size at age of transforming larvae and non-migratory early juveniles did not allow us to estimate a complete growth model for T. crenularis. However, a pronounced decrease in growth between larval and postlarval migratory phases was distinguished. The uncoupling of otolith and somatic growth was interpreted as a merged effect of downward migration of larvae to the mesopelagic transformation depth, prolonged stay of transforming larvae and early juveniles at this depth without performing diel vertical migrations, and shrinkage during metamorphosis. Back-calculated hatch dates suggests a prolonged spawning season of this species without any distinct peak.

Otoliths and vertebrae as potential hard structures for ageing South African yellowfin tuna Thunnus albacares

Sagittal otoliths and vertebrae from 46 yellowfin tuna Thunnus albacares (118-175 cm fork length) collected off the west coast of South Africa were assessed for potential usefulness in age estimation. Growth increments were found on both structures. Comparisons of growth increment counts showed that agreement in the counts of the number of growth increments was low (33-44%) but that most (90-94%) agreed to within one growth increment. Growth increment counts from whole otoliths, sectioned otoliths and vertebrae were not significantly different (f-test, p < 0.05). Among-reader precision was high for both whole otoliths (average percent error [APE] = 9.8%) and vertebrae (APE = 12.1%), but low for sectioned otoliths (APE = 34.9%). Age-bias plots indicated non-linear bias when sectioned otoliths were assessed in relation to other structures. Whole otoliths and whole vertebrae were considered equally precise, but the practicality of collecting vertebrae from the commercial fishery was better. Vertebrae are recommended as the most suitable structure for ageing yellowfin tuna.

Validation of Daily Growth Increment Formation in the Otoliths of Juvenile Cyprinid Fishes from the Brazos River, Texas

AbstractAge data are commonly used by fisheries biologists to assess a number of important population characteristics. For cyprinid fishes, there have been few attempts to assess the validity of age estimates, particularly those based on otolith microstructure. We assessed the periodicity of growth increment formation in the otoliths of three species of cyprinid from the Brazos River, Texas, two of which are of conservation concern. We immersed juvenile sharpnose shiners Notropis oxyrhynchus, smalleye shiners N. buccula, and plains minnow Hybognathus placitus in a 100‐mg/L solution of alizarin complexone for 24 h and sampled fish at 5‐d intervals for 30 d. Regression models indicated high correspondence between number of days posttreatment and number of growth increments between the alizarin mark and the edge of the otolith for all three species (sharpnose shiner: r2 = 0.99; smalleye shiner: r2 = 0.98; plains minnow: r2 = 0.97). Slopes of regression lines did not differ from 1.0 (t‐test: P &lt; 0.05), indicating that growth increments are deposited daily in these three species. Our results provide evidence that daily growth increments are reliable sources of age information for cyprinids.

Statolith microstructure and maximum age of the sepiolidRossia pacifica(cephalopoda, sepioidea) in the Northern part of the North Pacific

Abstract Statolith microstructure was studied in eight specimens of the boreal sepiolid Rossia pacifica (mantle length ranging from 45 to 90 mm) caught on the continental slope ofthe Northwest Bering Sea. Growth increments were present in all ground statoliths and were narrow and uniform in width (average 3.2–3.3 μm). They were grouped into inner opaque and outer translucent growth zones. The total number of growth increments within the statoliths of mature males (75–78) was lower than of mature females (95–117 increments). Assuming growth increments to be laid down daily, the life span from hatching to death of R. pacifica in the Bering Sea may be 4–5 months.

Growth and cuttlebone microstructure of juvenile cuttlefish, Sepia Qfficinalis L., under controlled conditions

The periodicity of deposition of growth increments in the cuttlebone of juvenile Sepia officinalis was investigated under controlled conditions for a short period after hatching (19 days). The slope of time elapsed and increment counts was significantly different from 1 indicating that lamellae are not deposited on a daily basis. The relationship between increment counts and juvenile length was, however, highly significant. Also significant were the relationships between the number of growth increments and shell length and increment counts and cuttlebone area. These data show that the number of growth increments is related primarily to the growth rate of the juvenile rather than to its chronological age. Taking into account these data, the cuttlebone lamellae cannot be used for age determination in the juvenile cuttlefish just after hatching.

Verification of daily growth increment formation in saury otoliths by rearing larvae from hatching

Naturally spawned eggs of the Pacific saury,Cololabis saira, were collected in the field and reared in a tank to examine daily periodicity of growth increment formation in the otolith. Larvae were 6.9 mm in knob length at hatching. Their otoliths (sagittae) were 31 μm in radius and had 3–6 faint concentric rings. They started feeding within two days and grew at a rate of 1.1 mm/day on average through larval and juvenile stages feeding on rotifers,Artemia nauplii, and artificial diets. Otolith growth increments showed a concentric pattern with a distance of 3.5–5.0 μm between two adjacent increments. The number of growth increments was almost equal to a known age in days plus 4 or 5. A regression line of number of increments (N) on known age in days (D) between 0–30 days after hatching was N = 4.81 + 1.01D, which shows that one increment was deposited per day.

耳石輪紋によるワカサギの日齢査定

Daily otolith increments of the Japanese smelt Hypomesus transpacificus nipponensis, were validated to establish the age determination method for the population study and the early life history of this species. Artificially fertilized Japanese smelt was sequentially sampled from the age of 0 day to 145 days and the number of growth increments on sagittae was counted. The sagittal radius at hatching was about 10μm regardless of water temperature: i.e.9.81±0.73μm at 19.5°C, and 10.03±0.82μm at 10.0°C.The relation between the days after hatching (X) and the number of growth increments on sagittae over 10μm in radius (Y) was expressed by the linear regression of Y=0.966X+0.389(r=0.992, n=96, P 0.1), and thus the daily deposition of sagittal increments was confirmed. The maximum deviation from the mean day was 5 days (4.5%) at 145 days. The ageing rate (No. fish successfully aged/No. fish examined) gradually decreased to 50% at 145 days after hatching. Consequently, this method of age determination can be applicable for fish younger than 145 days of the age.

Length of larval life in twelve families of fishes at ?One Tree Lagoon?, Great Barrier Reef, Australia

The length of larval life in some coral reef fishes was estimated from the number of growth increments in the otoliths of newly settled fishes. We examined 210 individuals comprising 38 species and 5 unidentified taxa, and belonging to 12 families. During 2 successive austral summers (1976–1977 and 1978–1979), specimens were collected from the lagoon at One Tree Reef, Great Barrier Reef, Australia. By assuming that growth increments in otoliths are laid down on a regular daily cycle commencing near the time of hatching, we calculated typical ages ranging from 3 to 6 wk with a minimum of just over 2 wk and a maximum of 12 wk. The otoliths also contain distinctive microstructural features which can serve as approximate temporal markers for the change from the postlarval to juvenile life stage.

Growth rhythms in the brachiopod Rafinesquina alternata from the Late Ordovician of southeastern Indiana

Growth rhythms are described in the accretionary skeletons of Rafinesquina alternata, a Late Ordovician brachiopod from southeastern Indiana. Contiguous growth increments widen and narrow in repeating series, giving the appearance of adjacent clusters of increments. Fourier analyses of growth increment widths and counts of the number of increments within individual clusters yield similar periodicities. Increments vary in width over a period of approximately 19 increments, modulated with a lower amplitude oscillation of 27 increments. The number of increments per cluster falls into two groups; clusters having between 8 and 17 increments outnumber those having between 18 and 30 increments.All specimens were obtained from a Maysvillian facies of the Dillsboro Formation, previously inferred to represent a shallow subtidal environmental setting. The growth periodicities described here are consistent with this interpretation. The intensity of tidal parameters such as emersion-immersion cycles, substrate shifts, changes in nutrient supply or in oxygen tension declines with depth as would the number of growth increments added each month in response to these factors. Thus, for these specimens, the maximum number of increments per cluster probably approximates the true number of “tidal” days in the Late Ordovician synodic month (period between full moons).The paleoecological model derived from these analyses can be used in future studies to predict the rate of the earth's rotation and the motion of the moon in the Late Ordovician and, equally importantly, to evaluate the limits of uncertainty of such studies.

Observations on shell deformities, ultrastructure, and increment formation in the bay scallop Argopecten irradians

Shell morphology and ultrastructure were examined in the bay scallop Argopecten irradians, cultured in recirculating seawater systems under various conditions of feeding, lighting, and handling. On a unialgal diet of Thalassiosira pseudonana, scallop growth ranged from 120 to 183 μm d-1 at 20°C in the laboratory, about two-thirds of the growth rate found in the field. However, shell deposited in the laboratory differed from that in the field in several ways. In the field, scallops formed costae as an unpigmented, corrugated marginal shell layer; shell deposited in the laboratory lacked this layer and was therefore darker. Also, microstructure of the exterior shell surface of field scallops was coarsely granular, while that of cultured scallops was relatively smooth. Excessive handling of scallops in the laboratory resulted in marginal thickening of valves, a deformity which was completely arrested by a change from daily to weekly handling. Scallops cultured in the same tank with oysters developed shell-thickening on the interior of the valves. It is postulated that shell abnormalities in bivalves result from disruption of complex behavioral processes associated with shell deposition and may be elicited by a variety of natural and experimental irritants. Under natural lighting regimes and optimal conditions for growth, scallops deposited exactly one shell increment per day, but under continuous lighting, deposition of growth increments often became aphasic. In one 28-d experiment, there was a strong correlation between number of growth increments formed and increase in shell height, suggesting that shell ridge formation occurred intermittently, rather than daily, when shell growth rates fell below approximately 150 μm d-1.