Age and growth of Hypophthalmus edentatus (Spix), (Siluriformes, Hypophthalmidae) in the Itaipu Reservoir, Paraná, Brazil

The age determination in fast-growing short-living species, such as European anchovy (Engraulis encrasicolus), has been widely recognized as a difficult task and bias introduced by readers leads to bias in reconstructing the population age structure. In this context, it is worth to note that age structure of fish population represents key information in fishery ecology and for stock assessment models. The uncertainty in estimating the age of the European anchovy by otolith reading is linked to the number of false-growth increments (checks) laid down before the annulus formation. While direct validation methods (e.g. mark-recapture, rearing, radiochemical dating) are difficult to implement specially for this short living species, the use of different indirect methods, supported by a coherent statistical approach, represents a robust and easier validation tool. A statistical modeling approach has been here adopted to assess the coherence of two well-known methods, namely Edge Analysis and Marginal Increment Analysis, in order to validate the first annulus formation in European anchovy. Both methodologies in two different yearly cycles converged toward the same result, thus confirming the annulus identification for the first year class. In addition, the completion dates of the checks and the first annulus were computed in order to gain a better insight into otolith growth dynamic. According to the species spawning period, the completion date of the first annulus falls in the summer period, while the first and second checks completion dates were mostly found in summer and winter respectively. General additive models using marginal increments as dependent variable showed a significant effect of the month, highlighting the presence of only one clear minimum in July/August, as well as specific relationships with condition factor and gonadosomatic index. Modeling the otolith edge morphology, the probability to find a hyaline band displayed in both years a similar shape, characterized by a minimum in July/August and higher values between November and January. The obtained results evidenced temporally coherent patterns providing a better insight in the otolith growth dynamic as well as a more robust validation of the first annulus formation in the European anchovy.

Kopf, R. K., Davie, P. S., Bromhead, D., and Pepperell, J. G. 2011. Age and growth of striped marlin (Kajikia audax) in the Southwest Pacific Ocean. – ICES Journal of Marine Science, 68: 1884–1895. This study describes the first validated model of age and growth developed for striped marlin (Kajikia audax). Daily periodicity of otolith microincrements was corroborated by back-calculated hatch dates that matched the known spawning season in the Southwest Pacific Ocean (SWPO). Yearly annulus formation in fin-spine sections was corroborated by daily otolith microincrements and by a marginal increment analysis. Ages of females ranged from 140 d to 8.5 years in fish between 990 mm and 2872 mm lower-jaw fork length (LJFL), and ages of males from 130 d to 7.0 years in fish between 1120 mm and 2540 mm LJFL. Sex-specific differences in growth were significant, with females growing to a larger asymptotic size and greater age than males. An instantaneous growth rate of 3.1 mm d–1 at 6 months and an estimated length of 1422–1674 mm LJFL by age 1 year makes this species among the fastest growing bony fish. Implications of these findings are discussed in relation to commercial longline and recreational fisheries management of striped marlin in the SWPO and in relation to the biology of pelagic fish growth.

We estimated the timing of annulus formation and the relationship between otolith radius length (whole view) and total length (TL) in yellow perch Perca flavescens from South Dakota lakes. Marginal increment analysis indicated that a single opaque band is formed during the summer months and that the timing of annulus formation varies with fish age. The lowest marginal increment measurements (i.e., those suggesting that annulus formation was recently completed) were most likely to occur in July, but at Waubay Lake the lowest increment for some cohorts was observed in August. Fish of age 4 or less were more likely to complete annulus formation during June. Personnel responsible for aging otoliths need to be aware of the differential timing of annulus formation. Significant relationships were observed between yellow perch TL and otolith radius length for 49 populations. Nearly all (98%) of the regression intercepts were negative. Back-calculated TLs were estimated from otolith annulus measurements using the direct proportion method and compared with the TLs previously measured for three populations. The back-calculated TL estimates were similar to the previously observed TLs, suggesting that the direct proportion method can be used to back-calculate TLs from yellow perch otoliths. Received February 18, 2011; acceptdate November 30, 2011

Walleye Sander vitreus and smallmouth bass Micropterus dolomieu were sampled monthly (May-October) from Lake Sharpe, South Dakota during 2006 and 2007 to estimate the timing of otolith annulus formation and to evaluate the influence of fish age, sex, and sample location (walleye only) on the timing and detection of annulus formation. Tim- ing of annulus formation was evaluated using marginal increment analysis. Walleye samples were stratified by age, sex, and sample location (i.e., upper and lower Lake Sharpe) and smallmouth bass samples were stratified by age and sex. Monthly mean marginal increment measurements for both species generally increased from May to June, declined in July, and slowly increased from August to October. Although monthly differences in marginal increment measurements across analysis strata were rarely consistent, July generally had the lowest mean marginal increment across species and strata, suggesting that annulus formation in walleye and smallmouth bass in Lake Sharpe likely occurs in July. The lack of dif- ferences in timing of annulus formation across species-specific strata was surprising given the well-known influences of age, sex, and water temperature on somatic growth. Nonetheless, results will aid managers in improving the accuracy of age estimates.

Age, growth and mortality of mutton snapper, Lutjanus analis, from the east coast of Florida, with a brief discussion of management implications

Removal efforts designed to avoid or minimize impacts from introduced lionfish, Pterois volitans (Linnaeus, 1758) and Pterois miles (Bennett, 1828), in the western Atlantic Ocean, Caribbean Sea, and Gulf of Mexico will be improved by reliable life history information applicable to the invaded range. For example, length at age has been modeled for lionfish from temperate North Carolina, but parameters characterizing growth are likely to differ in the tropics. Using Pterois spp. from Little Cayman, we validated formation of annual increments and daily rings in sagittal otoliths; documented ages; and estimated parameters for a length-weight relationship, multiple von Bertalanffy growth models, and an asymptotic vulnerability schedule. Formation of annuli was confirmed with marginal increment analysis, and daily ring deposition in juveniles was confirmed using an oxytetracycline hydrochloride marker. Total weight (g) estimated from combined data for both sexes was equal to 0.000003 × total length (mm)3.24. Logistic regression indicated that 50% of lionfish were vulnerable to removal at 129 mm total length. Sagittal otoliths (n = 499) from lionfish collected weekly between January and December 2011 indicated that males were 0-5 yrs old and females were 0-3 yrs old. A maximum likelihood approach to fitting von Bertalanffy equations estimated K and L 8 as 0.42 and 349 mm for the population, 0.38 and 382 mm for males, and 0.57 and 286 mm for females. An age-structured population model indicated that annual exploitation rates of 15%-35% may induce recruitment overfishing, with recovery to 90% of pre-removal biomass occurring 5-20 yrs after removals cease.

Age-validation and growth of bluefish ( Pomatomus saltatrix) along the East Coast of the United States

Nonlethal age-estimation methods for Florida Bass Micropterus salmoides using fin rays and spines would enhance trophy-bass research, management, and conservation. Nonlethal removal of fin structures would also expand opportunities for collecting age-related information, specifically during small-population projects as well as tournaments and citizen-science programs, for which sacrificing fish is not an option. We assessed the bias of age estimates derived from Florida Bass anal-, pelvic-, dorsal-, and pectoral-fin rays and anal-, pelvic-, and dorsal-fin spines by comparing them to age estimates derived from otoliths (i.e., sagittae), which are the standard for aging Florida Bass. We evaluated the precision of age estimates by calculating the absolute difference between replicate reads of each aging structure for each reader. Linear-mixed effects model selection indicated that precision was most affected by age, structure, and the age*structure interaction, in which the effect of age varied by structure. Age estimates from otoliths were the most precise, whereas pelvic spines were the least precise among all structures examined. Bias was similar across all fin structures, but the effect of age on bias varied by reader. Marginal increment analysis indicated that annulus formation was completed from November to March in Florida Bass dorsal spines, 5 mon earlier than in Florida Bass otoliths. Our results suggest that nonlethally removed fin structures, especially dorsal spines, have potential for use in estimating age, growth rates, mortality, and age structure of bass populations, which could be particularly beneficial where bass can reach unusual trophy sizes.

This study is the first detailed work on the age and growth of the leaping mullet (Liza saliens, Risso 1810) in the central Mediterranean. During the period 1991-1995 the age and growth of leaping mullet from the Messolonghi -Etoliko lagoon system (western Greek coast) were studied. Age and growth determinations were based upon otolith samples taken from 537 fish. Marginal increment analysis was used to validate age determination. Annulus formation took place around November each year. The back-calculated lengths at age estimated from the otoliths showed no differences between sub-areas of the lagoon system and the recorded limited between-years variability showed no persistent temporal pattern. The maximum age of leaping mullet in the Messolonghi - Etoliko lagoon was 5 years for males and 6 years for females. The von Bertalanffy equation (L‡=32.99±1.25 cm, k=0.258 ±0.017 year-1, t0=-0.47±0.04 year) accurately describes the growth of the total length of leaping grey mullet for all life stages (fry, juveniles and adults). A large spread and length overlap characterized the age groups. The estimated Length-Weight relationships were common for the two sexes (W=0.0079L3.01).

Age and growth of yellowtail snapper and queen triggerfish collected from the U.S. Virgin Islands and Puerto Rico

Summary The objective was to study seasonal aspects of the piracatinga catfish (Calophysus macropterus) growth and its relationship with the flood pulse. Analyzed from June 1997 to May 1998 were 446 specimens from the Amazon River. Using the period regression model with several biometric indexes gave the following results: two periods of low growth were identified in the vertebrae of C. macropterus, the first during falling water (August) and the second during rising water (January), using marginal increment analysis (MIA). This pattern was also observed in the annual variation of the regression coefficient of the length–weight relationship (b), and Feeding Index (FI), but an inverse relationship was observed with the Maturity Index (MI). These results suggest that reproduction occurs from January to February in the rising water season, when C. macropterus reaches sexual maturity at 1.4 and 1.5 of age for females and males, respectively. The parameters of Bertalanffy’s model were SL = 40.05[1−e−0.44(t−0.37)] for females and SL = 41.9[1−e−0.42(t−0.36)] for males. Natural mortality was high (♀:0.42–♂:0.40) and longevity low (♀:6.8–♂:7.1 years). The present study demonstrates that seasonal growth in C. macropterus is correlated with the flood pulse, especially in periods of rising and falling waters. These results, analyzed by the periodic regression model, showed that reproduction, migration or changes in feeding behavior have relationships with annulus formation in hard structures in this species. All quantitative indexes show clear seasonal variation to be correlated with river water level fluctuations.

A total of 200 specimens of Pomacanthus imperator from Dongsha Islands (South China Sea), were examined for age and growth. Scale radial length (R) is linearly proportional to standard length (L) and their relationship can be expressed by the formula L=3.6+43.8R. Relationship between standard length and body weight (W) can be expressed by the formula W=1.63×10−4L2.77. Mean standard lengths of each age group were back-calculated from scale annuli readings and were found to be 66.4, 94.2, 120.7, 133.9, 145.6, 157.9, 170.7, 188.0, 200.9, 217.6, 222.0, 242.8, 253.0, 268.1, 277.0 and 293.0 mm for age classes 1 through 16, respectively. The von Bertalanffy parameters L∞, K, and to fitted to back-calculated standard lengths were, respectively, 411.9 mm, 2852.1 g, 0.067 years−1, and −0.91 years. Marginal increment analysis indicated that annulus formation takes place between January and March.

We developed an integrated tagging model to estimate mortality rates and run sizes of Albemarle Sound – Roanoke River striped bass (Morone saxatilis), including (i) a multistate component for telemetered fish with a high reward external tag; (ii) tag return components for fish with a low reward external or PIT tag; and (iii) catch-at-age data. Total annual instantaneous mortality was 1.08 for resident (458–899 mm total length, TL) and 0.45 for anadromous (≥900 mm TL) individuals. Annual instantaneous natural mortality was higher for resident (0.70) than for anadromous (0.21) fish due to high summer mortality in Albemarle Sound. Natural mortality for residents was substantially higher than currently assumed for stock assessment. Monthly fishing mortality from multiple sectors (including catch-and-release) corresponded to seasonal periods of legal harvest. Run size estimates were 499 000–715 000. Results and simulation suggest increasing sample size for the multistate component increases accuracy and precision of annual estimates and low reward tags are valuable for estimating monthly fishing mortality rates among sectors. Our results suggest that integrated tagging models can produce seasonal and annual mortality estimates needed for stock assessment and management.

Biological and fishery characteristics of rubberlip morwong Nemadactylus douglasii (Hector, 1875) in eastern Australia

Age validation in the Lutjanidae: A review