Daily Rings Research Articles

Aspects of the early life history of the Japanese eel Anguilla japonica determined from otolith microstructure.

Otoliths (sagittae) of 22 elvers of Anguilla japonica which were collected in southern Kyushu, Japan, in December 1981 and January and March 1982, and in northern Taiwan in November 1981, and of two artificially hatched larvae were examined using scanning electron microscopy. Otoliths of five elvers of A. marmorata from the same places were also observed. The arrangement and other characteristics of otolith rings in both species were similar to those of the daily rings known for other species. The total number of rings in A. japonica for the November, December, January and March samples averaged 130.8, 155.2, 163.7 and 169.8, and that in A. marmorata for the November and January samples was 146.3 (mean) and 133, respectively. The otolith of 6 day old larvae indicated that the first ring in the elvers was not formed at hatching. The spawning time was estimated to be June-October 1981 for A. japonica, and May-August 1981 for A.marmorata, respectively. The three samples from southern Kyushu differed with each other in the time of spawning, the location of and/or the route from the waters they were spawned. The December elvers may have grown faster than the March elvers.

Growth of larval pelagic fish in the South-East Atlantic from daily otolith rings in 1982/83 and 1983/84

Larval growth was examined for pilchard, anchovy and round herring collected off South West Africa and from South Africa's Western Cape during the spawning seasons of 1982/83 and 1983/84. Rings on otoliths were validated as daily by examination of reared larvae. Larvae from 1982/83 were aged by ring counts on otoliths. It is demonstrated that the growth of larvae from 0,5 to 2,5 cm can be approximated as linear. A method is described for the calculation of daily growth rates from otolith increments. Daily growth rates over the most recent five days of life showed significant differences between months and stations and the differences may be correlated with temperature. Pilchard growth rates were more variable than those of anchovy. Back-calculated daily growth rates show that growth rate may change rapidly.

Early growth in length of the anchovyEngraulis capensisGilchrist off South Africa

Growth in length of the anchovy Engraulis capensis (= E. japonicus) off South Africa during its first year of life was determined by means of daily ring enumeration and analysis of length frequency distributions of the 1964–1983 commercial purse-seine catches. Growth rate is of the same order as that of anchovy found off the coasts of South West Africa, Japan and Chile. After an initial fast growth period, during which 4 cm caudal length is attained within three months, the growth rate slows down, resulting in a caudal length of approximately 11,1 cm at one year of age.

The growth of herring larvae, Clupea harengus L., in the Clyde: an assessment of the suitability of otolith ageing methods

Wild herring larvae were sampled from the Firth of Clyde, Scotland in 1980 and 1981 to assess the suitability of otolith ageing methods for herring larval studies. The ages and growth rates were estimated directly from otolith ring counts, by comparison of ring counts with the results of validation studies on reared larvae of known age, and by back‐calculation. Growth rates based on otolith data were compared with indirect calculations based on length at capture. The assumption of daily ring deposition, even allowing for a period of lag before the initiation of daily ring deposition, led to incorrect predictions for age at yolk‐sac absorption, and back‐calculations led to overestimated growth rates, indicating that ring deposition does not begin at hatching and that light microscope counts give a rate different from one ring per day in wild herring larvae.

Daily Growth Rings in Otoliths of Young-of-the-Year Largemouth Bass

Daily rings were found in the otoliths of laboratory-raised, young-of-the-year largemouth bass Micropterus salmoides for at least 151 days after swim-up. Ring formation began at hatching but the total complement of prolarval rings was visible for only 10–15 days after swim-up. Subdaily rings were visible in the posterior field but were easily distinguished from daily rings. Both high- and low-contrast tissues were present in otoliths from fish over 45 days old. Sagittal and frontal sections yielded ages of similar accuracy but sagittal sections were much easier and faster to prepare and nearly twice as many were readable. Otolith growth was directly proportional to body growth and the regression intercept was not substantially different from 0.

Verification of the Formation of Annuli in Otoliths of Largemouth Bass

Annuli in transverse thin sections of otoliths from largemouth bass Micropterus salmoides were verified by four methods. First, the number of daily rings between successive annuli was similar to the potential number of growing days in each of the first 3 years of life. Second, all of the annuli were formed between the last of April and the first part of July. Third, the lengths of age-I-VI largemouth bass back-calculated from otoliths were very similar to those determined from a mark-recapture study. Fourth, the number of otolith annuli agreed with the known ages (II+ and V+) of largemouth bass in samples from a hatchery and a lake.

Individual growth and size-selective mortality of larval turbot (Scophthalmus maximus) reared in enclosures

Larval turbot (Scophthalmus maximus) were reared in a large marine enclosure and in plastic bags in southern Norway. Samples of larvae in the enclosure were taken during the first 12 d of life to estimate individual body growth based on back calculations from daily growth rings on their otoliths. Size selective mortality was documented for these larvae in the predator-free enclosure. Starvation in the laboratory occurred on the seventh day. In the enclosure, a mortality rate of 18.1% d-1 prevailed. Our data indicates that the survivors beyond the starvation period are larger by 0.18 mm on average. This result is important with regard to the question of whether starvation is an important mechanism for larval mortality in the sea. A possible means of estimating the relative effects of starvation versus predation based on these results and the backcalculation technique is suggested.

Growth ofTodarodes sagittatus(Lamarck) (Cephalopoda, Ommastrephidae) from the northeast Atlantic, based on counts of statolith growth rings

Abstract Growth is described from size-at-age data. Size-at-age was determined from counts of daily growth rings on the statoliths of 65 individuals. A mean growth rate of 2 mm/day was calculated for a dorsal mantle length range of 15-52 cm. The month in which each individual hatched was back-calculated from the age data. A histogram of the frequency of hatching through the year is presented and shows peaks in May and October.

Daily Growth Rings in the Otoliths of Juvenile Sockeye Salmon (Oncorhynchus nerka)

Sockeye salmon fry were collected from the Fulton River spawning channel at Babine Lake, British Columbia, in May 1978. The fish were reared for 26 d in enclosures in the spawning channel and were sampled every 7 to 10 d. The sagittae were removed from 25 fish from each sample, and the growth rings in one otolith from each fish were counted. A regression of the number of rings on the number of days since capture showed that these rings are, on average, formed daily, beginning at the time of emergence. A number of possible technical and biological causes of variation in ring counts within and between samples are considered.Key words: otolith, sagittae, daily growth rings, sockeye salmon fry

Daily Growth Rings on Otoliths for Aging Young-of-the-year Largemouth Bass from a Wild Population

(1980). Daily Growth Rings on Otoliths for Aging Young-of-the-year Largemouth Bass from a Wild Population. The Progressive Fish-Culturist: Vol. 42, No. 2, pp. 78-80.

Estágios iniciais de crescimento da pescada (Plagioscion monti Soares)

Resumo A idade de 370 espécimes de P. monti foi determinada contando os anéis diários presentes nos otólitos. O comprimento padrão dos peixes examinados varia de 0,7 — 15 cm. Dentro deste intervalo de tamanho o aumento de comprimento pode ser considerado linear enquanto o aumento de peso uma função exponencial. A função para o aumento de comprimento foi: L = 0,0707 T + 0,1263; e para o peso W = 4,86 10-5 T2,5552. o crescimento não é contínuo mas periodicamente interrompido em relação às fases da lua. O comportamento de desova também parece estar influenciado pela lua.

The Use of Otolith Growth Rings to Age Young Atlantic Silversides, Menidia menidia

Abstract There is evidence that daily growth rings are deposited in the sagitta otolith of larvae and juvenile Atlantic silversides, Menidia menidia. The growth rings are a function of age alone, and can be used as a tool to age young Atlantic silversides. Growth rings deposited in the asteriscus otolith were unreliable indicators of daily age.

Daily Rings in Otoliths of Three Species of Lepomis and Tilapia mossambica

Daily rings formed on otoliths of known-age, laboratory-raised pumpkinseed (Lepomis gibbosus), green sunflsh (L. cyanellus), bluegill (L. macrochirus), and mozambique mouthbrooder (Tilapia mossambica) for at least 176, 170, 125, and 60 days, respectively. Subdaily rings found in young laboratory and wild fish were easily distinguished from daily rings. Width of daily rings on otoliths of green sunfish was linearly related to daily increase in length of fish, but the number of rings was a product of age of fish only, not length of fish or otolith radius. Growth and daily ring formation on otoliths in wild bluegill and largemouth bass (Micropterus salmoides) appeared to be similar to those in laboratory-raised fish. Otoliths of green sunfish held under simulated winter conditions ceased to produce daily rings, but did form an annulus. Two kinds of otolith tissue were present in most of the larger laboratory fish and wild bluegill but were not observed in wild largemouth bass. The first type, present in all areas of the otolith except the extreme posterior end, was translucent and had well-defined daily rings. The second type, present only in the posterior end, was opaque and had poorly etched daily rings that were difficult to discern. Both tissues were calcium carbonate in the aragonite form. Daily rings were found on otoliths offish held at constant temperature. Results of experiments with young mouthbrooders held under various light–dark and feeding cycles suggested that a 24-h light–dark cycle that entrained an internal, diurnal clock was required for daily ring production.

The seasonal factor in prehistoric New Zealand

Abstract Accounts of the first European explorers of New Zealand emphasize the strong relationship between Maori subsistence activities and the season of the year. Any attempt to trace the economic development during the prehistoric period must involve a valid seasonal dating technique. Although certain bird and fish species were available on a seasonal basis, they may well have been preserved and traded, thereby ruling out any estimate of the season during which a given site was occupied. Attention has therefore been given to analysing the growth characteristics of the cockle (Chione stutchburyi). The presence of daily growth rings in these bivalves permits the season of occupation of coastal sites to be ascertained. The implications of this technique are discussed in the light of a number of southern New Zealand archaeological sites.