The effect of temperature and somatic growth on otolith growth: the discrepancy between two clupeid species from a similar environment

Otolith growth rates of the early life stages of herring Clupea harengus ( n = 472) and smelt Osmerus eperlanus ( n = 348) collected in the Vistula Lagoon (Baltic Sea) during 1997–1999 were analysed. The larvae and early juveniles were not only collected in the same geographical area they were also of the same size (range 15–43 mm standard length, L _S), similar ages and were collected during the same seasons (May to July). Although the two clupeid species experienced very similar environmental conditions, there were significant discrepancies in the analysed relationships. The otolith growth of larval and juvenile smelt was very strongly related to somatic growth while temperature had a minor effect. In herring, the effect of somatic growth, although clearly visible and statistically highly significant, was of less importance than temperature. Furthermore, variation in the otolith size and L _S relationship was affected by temperature and somatic growth in both species, but the variance of otolith size at L _S was higher for herring than for smelt. Although growth backcalculation from otoliths can presently be recommended as an appropriate method for use with both smelt and herring (despite possibly lower precision and accuracy with the latter), other methods referring directly to short-term increment width changes ( e.g. marginal increment analysis) are recommended for smelt but not for herring.     

Comparison of otolith growth and morphology with somatic growth and age in young-of-the-year bluefin tuna

Otolith morphological characteristics were studied using image analysis techniques and the relationships between otolith growth and somatic growth and age, as estimated from counting daily otolith increments, were examined in young-of-the-year (YOY) bluefin tuna Thunnus thynnus ranging in fork length ( L _F) from 8·5 to 55·5 cm. Whole otolith length, width, area and perimeter, and three shape indexes, circularity, E value and rectangularity, were extracted for each pair of sagittae. Since no statistical significant differences between left and right otolith morphometrics were found, only one otolith from each fish was used for correlations. Statistically significant relationships were observed between otoliths measurements and fish somatic growth when a linear regression was applied after logarithmic transformation of all variables tested. Among the variables, otolith length was the one that showed the highest correlation with L _F, followed by otolith area and perimeter, whereas otolith rectangularity exhibited the lowest correlation. Statistically significant relationships were also observed between the otolith variables tested and the age of the fish, which ranged from 20 to 129 days. The ages estimated using otolith mass were very close to those assessed using daily increment counts (bias ranged from 1 to 24 days). Therefore, otolith mass could represent a valuable criterion for age estimation in YOY bluefin tuna that is objective, economic and easy to perform compared to daily increment counting method.     

Correlation among dominance status, metabolic rate and otolith size in masu salmon

In spatial competition between individuals, neither fish sex nor body mass affected dominance status in masu salmon Oncorhynchus masou . In contrast, resting metabolic rate ( M _R) was significantly correlated with dominance status, indicating that a high metabolic rate can increase the dominance rank of juvenile salmon. Whole animal growth rate was significantly correlated with M _R, but not with initial body weight. This suggests that the body size of masu salmon is not a cause, but rather a consequence, of dominance status which is closely related to M _R. The increment width between otolith daily rings was also significantly correlated with M _R. Thus, the size of the Otolith may indicate the degree of M _R.     

Differences in temperature conditions and somatic growth rate of larval and early juvenile spring-spawned herring from the Vistula Lagoon, Baltic Sea manifested in the otolith to fish size relationship

Larval and juvenile herring Clupea harengus collected in the Polish part of the Vistula Lagoon in May-July 1997 had hatched between 17 April and 9 June and originated from three cohorts. The spawning season began on 1 March at 3·8° C and was completed on 3 June at 12·7° C. Mortality among larvae was high in the first 2 weeks of April, probably associated with significant temperature decrease at the beginning of the spawning season. The growth of 10–48 mm L _S herring was linear, highest for larvae and juveniles from the first cohort (0·58 mm mm^-1 day^-1), slower for the second cohort (0·55 mm mm^-1 day^-1) and the slowest for the third cohort (0·45 mm mm day^-1). Temperature effects on the growth were inconclusive and potentially unfavourable feeding conditions in June might have been responsible for the relatively slow growth of third cohort larvae and juveniles.
Relationships between otolith size (perimeter, length, width, area, and weight) and fish size ( L _S) differed among the three cohorts, related mostly to the positive temperature effect on otolith growth, individuals growing in warmer water had larger otoliths. Although a negative growth rate effect was observed as well, it was less significant.     

Early life history of herring larvae in contrasting feeding environments determined by otolith microstructure analysis

Newly hatched autumn-spawned herring larvae Clupea harengus were released in two 2500-m³ outdoor mesocosms and reared over a 2-month period. Hydrographic conditions were similar in the two mesocosms, but the average plankton density was initially more than 10 times higher in mesocosm B compared to mesocosm A (>11⁻¹ v. <0.11⁻¹). Half-way through the experiment the feeding conditions reversed with three times higher average densities in mesocosm A than in mesocosm B (>31⁻¹ v. ∼11⁻¹). Herring larvae were sampled with a 0.3-m² two-chambered net twice weekly, and survivors were harvested by draining the mesocosms at the end of the experiment. Otolith growth trajectories of individual larvae were determined by relating radial otolith size with number of increments from the outer edge of the otolith (days before capture). The increment widths during the first 3 weeks after hatching, including the first-check size, were generally wider among larvae from mesocosm B (relatively good initial feeding conditions) than among those from mesocosm A (poor initial feeding conditions). The otolith growth pattern also confirmed that the surviving herring in mesocosm A belonged to the upper size range of larvae in the mesocosm after only 2–3 weeks from hatching; no such trend was found in mesocosm B. In both mesocosms the otolith size-at-age indicated that with the present sampling gear, herring larvae larger than 20–25 mm were underrepresented in the net samples. The information obtained from otolith-size-at-age is compared with other morphometric and biochemical measures of size and condition of larvae obtained throughout the experiment.     

Influence of water temperature and feeding regime on otolith growth in Anguilla japonica glass eels and elvers: does otolith growth cease at low temperatures?

The influences of water temperature and feeding regime on otolith growth in Anguilla japonica glass eels and elvers were investigated using individuals reared at 5, 10, 15, 20, 25 and 30° C and in fed or unfed conditions at salinity 32 after their otoliths were marked with alizarin complexone (ALC). To eliminate the difficulty of observing the edges of otoliths with optical (OM) or scanning electron (SEM) microscopes, three to 10 individuals were sampled from each tank at 10, 20 and 30 days during the experiment and reared for an additional 10 days at 25° C after their otoliths were marked a second time. Otolith growth and the number of increments were measured using both OM and SEM. Most A. japonica commenced feeding after 10 days at 20–30° C or after 20 days at 15° C, but no feeding occurred at 5 and 10° C. No otolith growth occurred at 5 and 10° C except in two individuals with minimal increment deposition at 10° C. Otolith growth was proportional to water temperature within 15–25° C and not different between 25 and 30° C. At 15, 25 and 30° C, the mean otolith growth rate in fed conditions was higher than in unfed conditions. The number of increments per day was significantly different among water temperatures (0·00–0·01 day⁻¹ at 5 and 10° C, 0·43–0·48 day⁻¹ at 15° C and 0·94–1·07 day⁻¹ at 20–30° C). These results indicated that otolith growth in A. japonica glass eels and elvers was affected by temperature and ceased at ≤10° C under experimental conditions. Hence, future studies analysing the otoliths of wild-caught A. japonica glass eels and elvers need to carefully consider the water temperatures potentially experienced by the juveniles in the wild.     

Growth of North Alboran Sea sardine larvae estimated by otolith microstructure, nucleic acids and protein content

Wet mass and DNA, RNA and protein content increased significantly with standard length ( L _S) of sardine Sardina pilchardus larvae, collected in January 1995, in the Bay of Málaga, North Alboran Sea. L _S, wet mass and DNA, RNA and protein content were closely related allometrically to otolith radius ( R ). Larval daily length increments decreased but DNA, protein and wet mass daily increments increased with larval age. Daily length increments showed a negative and poor relationship with long-term otolith growth. In contrast, DNA, protein and wet mass daily increments were positively correlated. Differences between observed and back-calculated otolith radius-at-age indicated that larvae with slow otolith growth were under represented in older age groups, suggesting the existence of growth-selective mortality. Recent otolith growth, estimated from the mean widths of the last six increments, increased with age and R . Individual RNA: DNA and protein: DNA ratios were correlated significantly, although weakly, with L _S and larval growth.     

Abundance,structure, growth and origin of inshore clupeid populations of the west coast of Scotland

The abundance, structure, growth, and origin of clupeid populations in inshore waters of the west coast of Scotland were studied from April 1970 to October 1972. Clupeid populations in the area comprise mainly young fish. 0-group autumn-spawned herring, probably of Minch origin, move into the area about April and spring-spawned ones (Clyde origin) about June. The timing and the body length at which each group arrives in the area during the different years is the same. After the initial immigration, the distribution of both 0-group clupeids becomes localized.Herring populations in the sea-lochs and associated inshore waters are mainly 0-group fish, which are replaced each year by a new incoming brood. The sprat populations of the sea-lochs are dominated by the 0-group; in the more ‘open’ areas the populations comprise older individuals. Year-class distribution in the ‘open’ areas resemble that of the commercial fishery.The rate of increase of 0-group autumn-spawned herring is 3.68 mm/week and that of spring-spawned 0-group herring is 2.83 mm/week. The curves of growth of 0-group sprats of the 1970 and 1971 year-classes are different; the rate of increase in length, however, averages 3.55 mm/week for both year-classes and the differences are not significant.In sprats, after their first year of life a rapid increase in length takes place in the spring. This increase is thought to enable the majority of the population to reach the minimum size (88–90 mm) for initial gonadal maturation and thereby make them capable of reproducing in their second year of life.     

Effects of different food restrictions on somatic and otolith growth in Nile tilapia reared under controlled conditions

.Nile tilapia Oreochromis niloticus , initial age 12 days, were given an unrestricted (NR) or restricted (R) ration over 93 days which resulted in fish of very different sizes although the body condition factor ( K ) and the viscero-somatic index ( I _V) remained almost unchanged. In a second stage (64 days) each group (NR & R) was divided into three subgroups that were subjected to 0 (NR0, R0), 15 (NR15, R15) and 30 (NR30, R30) days of food restriction, respectively. The impact of the different treatments on the somatic growth during the second stage of the experiment had an effect, with a highly significant difference between the mean ± S.D. masses ( M _T) in the different subgroups (NR0= 115.0 ± 26.6 g; NR15 = 94.8 ± 24.9 g; NR30 = 56.3 ± 28 g; R0 = 76.4 ± 20.1 g; R15 = 72.l ± 17.6 g; R30 = 43.6 ± 17.2 g). Similarly, K and I _V decreased. Irrespective of the initial feeding condition, the width of the otolith microincrements started to decrease at the end of the first or second day of restricted feeding. In the subgroups given a restricted food ration for 30 days (NR30 and R30), this decrease reached a plateau at about day 30, which was maintained even when the restriction had ended. This slowed growth did not lead to any marked halt in microincrement formation, since there were no significant differences (ANOVA; P >0.05) in the numbers of increments counted in the various subgroups. The results show that in 153 day old fish, a period of severe food restriction, even if prolonged (15 to 30 days), had no influence on the timing of the laying down of microincrements but only affected their growth.     

Sex-specific somatic–otolith growth relationship in two Gadidae

Otolith and somatic mass of two Gadidae ( Merlangius merlangus and Trisopterus minutus ) were compared in order to analyse the sex-specific relationship between otolith and somatic growth at age. In the present study, otolith mass appeared a reliable indicator of age in both species. Otolith growth reflected somatic growth, but the relationship between these characters varied and differed between species and sexes.     

Otolith description and age‐and‐growth of Kurtus gulliveri from northern Australia

The sagitta of Kurtus gulliveri was ovate, moderately thick with the following attributes: lateral surface convex, mesial surface flat; dorsal margin sinuate, posterior margin rounded ventrally, ventral margin rounded and irregular; sulcus divided into ostium and cauda by constriction of dorsal and ventral margins, heterosulcoid, colliculum heteromorph; dorsal depression large and distinct, ventral groove close to margin in larger otoliths; rostrum broad and antirostrum small, separated by wide, shallow excisural notch. Otolith size was moderate, average 4·6% standard length ( L _S), typical for a perciform. Annuli on 78 whole sagittae were read, and 15% of these were transversely sectioned for verification of the annuli. Males ranged from 94 to 235 mm L _S and females from 95 to 284 mm L _S. There was little difference in size distribution of the sample between the sexes, perhaps due to a 6 month spawning season over which young were continually added to the population. Some sexual dimorphism was noted, however, as age 2 year females were significantly larger than males of the same age. The largest fish aged was a 284 mm L _S, 3 year‐old female, and the oldest age reached was 4 years by two males. It appears likely that most spawning females are ≥2 years old, but some larger 1 year old fish may attain sexual maturity.     

Larval Konosirus punctatus(Clupeidae) in a brackish river mouth on the Pacific coast of central Japan

Eggs of Konosirus punctatus in early developmental stages were collected from the eastern part of the mouth of Sagami Bay on the Pacific coast of central Japan. Advanced‐stage eggs and early larvae with notochord length ( L _N) of <7·5 mm were collected from the inner bay near the mouth of the Sagami River. Feeding larvae of >8·4 mm L _N were distributed in the mouth of the river, and juveniles of 24–90 mm standard length ( L _S) were collected from the lower reaches of the river between the river mouth and c . 3 km upstream of the river mouth. Hatch dates of larvae and juveniles collected in 2001 ( n  = 158) and in 2002 ( n  = 109) extended from late March to late July. The relationship between the otolith radius ( R _O) and L _N or L _S changed during the metamorphosis stage as characterized by 320 μm R _O and 22 mm L _S. Otolith growth rate, as an index of somatic growth rates in larval and early juvenile stages, was higher in cohorts that hatched later in the spawning season, i.e . from March to July. Konosirus punctatus that were spawned in the bay mouth area survived with different growth histories in the bay and lower reaches of the river, and recruited to the young‐of‐year population in the Pacific coastal waters of central Japan.     

Validation of daily otolith increments in larval and juvenile Chinese sucker, <Emphasis Type="Italic">Myxocyprinus asiaticus</Emphasis>

Otolith development was observed and the formation of daily growth increments in otoliths of Chinese sucker, Myxocyprinus asiaticus, was validated by monitoring known-age larvae and juveniles in the laboratory from 2003 to 2005. Otolith shape changed with larval and juvenile development, and there was an exponential relationship until a body length of 16 mm or so, and a linear relationship after a body length of 16 mm between otolith size and fish size. The first increment was identified in larvae 1 day after hatching. The regressed equations between daily age (D) and increment number in otoliths (N) were N = −0.64 + 0.96D in lapillus, and N = −0.31 + 0.98D in sagitta. The slopes were not significantly different than 1.0. This demonstrated that otolith increments in this species were formed daily and can be used for daily age determination.     

Growth and otolith microstructure of cod (Gadus morhua L.) larvae

Cod larvae from Irish Sea stocks were reared under differentgrowth conditions, and the otolith growth and increment formationexamined in sagittae and lapilli. Otolith increments were firstdeposited around the time of hatching and increment counts,on average, reflected larval age. The growth rate of fish larvaereared in different sized tanks was significantly different(P < 0.001), but there was no detectable effect on incrementformation. Otolith size was independent of larval size for individuals<5 mm in length. In larvae >6 mm, larger, faster growingindividuals had larger and faster growing otoliths.     

Comparison of growth rate and formation of otolith increments in age-0 red snapper

For wild red snapper Lutjanus campechanus , mean otolith increment deposition rate after marking with oxytetracycline dihydrate (OTC) was daily (0.97 increments day⁻¹) when growth rates were fast (0.63 mm fork length, L _F day⁻¹), but were not daily (0.82 increments day⁻¹) when somatic growth was slow (0.2 mm L _F day⁻¹). For reared larvae ( n =8), increment deposition rates were daily (0.99–1.03 increments day⁻¹), and growth rates ranged from 0.6 to 0.9 mm L _F day⁻¹. Growth rate affected increment deposition rate as a threshold function, i.e. when growth rate was <0.3 mm L _F day⁻¹, deposition was less than daily, but above this level increment deposition did not exceed a daily rate. As growth rates increased increment widths increased. Examination of a sub-sample ( n =8) of the otoliths from the slowest growing wild fish by scanning electron microscopy did not increase increment counts. Because L. campechanus are late spring-early summer spawners, young fish can expect maximum growth due to warm summer temperatures. Thus, daily ageing methods should be well suited to this species.     

Growth of the clupeid fishes, Stolothrissa tanganicae and Limnothrissa miodon, in the Zambian waters of Lake Tanganyika

The age and growth of two endemic Lake Tanganyikan clupeid fishes, Stolothrissa tanganicae and Limnothrissa miodon , were estimated from analysis of otolith microstructure in specimens collected in Zambian waters from October to December 1990. Both species had relatively clear, concentric otolith increments which were believed to represent daily increments based on their similarity to daily increments found in some marine clupeid species. The growth rates estimated from length-at-age data were: for S. tanganicae, L_t = 104·0 (1 – exp (– 0.00512 ( t – 5·8))); for L. miodon, L_t = 155.4 (1 – exp (– 0.00236 ( t +8.1))). In most cases, the growth parameters obtained from otolith analyses generally agreed with those previously estimated from analyses of length-frequency distributions.     

Temperature, selective mortality and early growth in the short-lived clupeid Spratelloides gracilis

Six cohorts of the silver-stripe round herring Spratelloides gracilis , a fast-growing and short-lived tropical clupeid, were collected as juveniles and then as adults during austral summers from November to February in 1998–1999 and 1999–2000, using light traps in the Dampier Archipelago, Western Australia. Otolith analysis allowed backcalculation of size and growth rate at age to examine the relative influences of selective mortality and water temperature on early growth. Negative size-selective mortality and growth-selective mortality between the juvenile and the adult stages was found only in the cohort that was the smallest and slowest growing in the period immediately following hatching. Selective mortality preferentially removed members of this cohort that were smaller from age 0 to 15 days, and slower growing from 0 to 10 days, resulting in an elevation of size at age to, or even above, that of cohorts that had not undergone this process. Size and growth rate at 5 day age intervals in the first 20 days after hatching differed among cohorts within and between summers and were strongly and positively correlated ( r ²= 0·61–0·83) with water temperature.     

Comparison between micro- and macro-structure readings in the age estimations of Cape hake

By counting otolith daily increments juvenile Cape hake Merluccius capensis were found to grow faster than European hake Merluccius merluccius . The mean frequency of translucent zones in juveniles 130–240 mm L _T were higher (×3·2) than the annual frequency, although their mean duration was shorter (1 month) than a season. Comparison between micro- and macro-structure readings showed that the latter tended to overestimate the age of juvenile hake, with 1 year old hake being overestimated by 18% in individuals of 160 and 210 mm L _T.     

Lifetime consequences of variable 0 year group length in riverine populations of chub Leuciscus cephalus (L.)

The fork length ( L _F) of individual chub Leuciscus cephalus in English riverine populations at the end of their first growth season varied considerably, ranging from <25 to >70 mm. This had a significant influence on the subsequent growth of individuals over their lifetime. Chub of small L _F at age 1 year generally produced smaller annual growth increments throughout life than those of longer L _F at age 1 year, although they had the potential to attain greater ultimate L _F. This variability in L _F at age 1 year resulted, at least in part, from multiple spawning events over a protracted period, that caused variation in the growing seasons for 0 year group chub of the same year class. Since the adult population contained individuals that only attained L _F of <25 mm at the end of their first growing season, it is possible that L _F at age 1 year may not be such a major precursor to strong chub recruitment as previously thought.     

Effects of river flows on growth of redbreast sunfish Lepomis auritus (Centrarchidae) in Georgia rivers

Effects of river discharge on growth of redbreast sunfish Lepomis auritus were investigated in nine rivers in Georgia, U.S.A. Fish were aged and annular total length increments ( L _Tinc) estimated from measurements from sectioned sagittal otoliths using the generalized regression model that held for the effects of decreasing L _Tinc from annual age ( X ): L _Tinc= b _o− b ₁( X ) ± b _i( D ), where b _o, b ₁ and b _i were the regression coefficients for the intercept and slopes and D , discharge, was either a single or multiple measurements of annular or seasonal flow volume or variation in flow volume. For eight of nine rivers, higher or greater variation in flows from April to June was associated with greater L. auritus growth; in the last river, higher flows from January to March were associated with greater fish growth. Across all rivers, L. auritus growth increments were 22, 45 and 36% greater in a wet year v . a dry year at ages 1, 2 and 3 years, respectively. Based on the results of this study, increasing water withdrawals by an additional 30% in five Georgia rivers would reduce the predicted number of L. auritus recruiting to 203 mm (angler preferred size) by 19–62%.