Otolith Development, Increment Formation, and an Uncoupling of Otolith to Somatic Growth Rates in Larval and Juvenile Goldfish.

Abstract

Growth rate effects on the relationship between otolith size and body size were examined in larval and juvenile goldfish. They were kept under the same environmental and feeding conditions , and sampled ad libitum until 154 days after hatching. Therefore, their variations in body size will be explained by internally mediated constraints on growth. After measurement of body size in standard length, three kinds of otolith were dissected under a binocular microscope and their m orphological changes were noted.The asteriscus was too small to be dissected consistently at hatching. The sagitta was considerably deformed with growth. The lapillus was relatively large at hatching and grew steadily from a round to a pear shape. For this reason, lapilli alone were used to measure otolith length (diameter or long axis) and to count the number of otolith increments.Otoliths had three increments at hatching and subsequent increments deposited on a daily basis until at least 154 days after hatching. The relationship between otolith and body length showed an excellent correlation (r=0.92-0.97) within three groups which had different growth rates. However, analysis of covariance revealed a different slope of regression among the groups. This indicates that slow-growing fish have larger otoliths than equal-sized, rapidly growing fish.Otolith reading has been developed from the microstructural and microchemical points of view, and has provided various information about the growth history of the individual fish. Part of such information is the estimation of the previous somatic growth rate with the aid of otolith increments. This is based on the general consensus that otolith growth has a linear relationship to somatic growth. However, recent studies have reported an uncoupling relationship between otolith and somatic growth. Secor and Dean1) found such a relationship in striped bass Morone saxatilis experiencing fast and slow growth due to different pond conditions. Slower growing bass had larger and heavier otoliths, relative to fish length, than did faster growing ones. Similar results were reported in Arctic char Salvelinus alpinus2) and guppies Poecilia reticulata,3) growth rates of which were manipulated by controlling aquatic temperature and food availability, respectively. Therefore, these studies were conducted in relation to externally controlled constraints on growth.It is common that juvenile fish show marked differences in somatic growth even when they are kept under the same environmental conditions. These differences will mostly be due to genetic (internally mediated) events. Therefore, it should be studied how internally mediated variations in somatic growth rate are related to otolith growth. The only study in this field is by Wright et al.4) who presented uncoupling evidence between two groups of Atlantic salmon parr Salmo salar which smolted aged 1+or 2+.Using larval and juvenile goldfish Carassius auratus kept under the same environmental and feeding conditions, the present study was undertaken to provide more i...

Validation of daily otolith increments in larval and juvenile Chinese sucker, Myxocyprinus asiaticus

“…Sagitta was broadly used in age determination or microstructure analysis, while sometimes the lapillus and asteriscus were also used. In Cyprinidae species, however, researchers recommend that lapillus be used (Victor and Brothers 1982;Mugiya and Tanaka 1992;Chang et al 1994). In the Chinese sucker, the asteriscus was unsuitable for age determination due to its emerging more than 10 days after hatching of larvae and the unclear and irregular increments on it.…”

“…However, the validation of daily increment formation in different species is still a necessary prerequisite to otolith microstructure work of any kind (Campana and Neilson 1985). Validation methods include the monitoring of known-age fish in the laboratory (Mugiya and Tanaka 1992;Chang et al 1994;Xie et al 1995a, b;Fu et al 1997), marking with fluorescent substances (Villanueva and Molí 1997;Song and Cao 1999;Arai et al 2000;Cieri and McCleave 2001;Sugeha et al 2001), statistical inferences (Joyeux et al 2001;Morley et al 2005), and marginal increment analysis (Moku et al 2005). Among these methods, monitoring of known-age larvae was regarded as the most accurate and reliable method of validating daily increments, and was frequently used (Campana 2001).…”

Relationships between Fish and Otolith Size of the Blackspot Snapper <i>Lutjanus ehrenbergii</i> (Peters, 1869) Collected from the Coast of Muscat City, Sea of Oman

“…Similarly, Jawad et al (2011c) showed the same results on Lutjanus benghalensis from Omani waters. The relationship between otolith length width and fish body proportions is related to the growth rate of the fish (Mugiya and Tanaka, 1992) and these relationship became curvilinear in some larval or juvenile fishes (West and Larkin, 1987), such curvilinearity was observed in the present study, but not in the previous similar studies on fishes from Oman (Al-Mamry et al, 2010;Jawad et al, 2011a;Jawad and Al-Mamry, 2012). Harvey et al (2000), Waessle et al (2003) and Battaglia et al (2010) have suggested that there is a possibility of getting error in the final results of the relationship between otolith dimensions and fish size due to changes in this relationship during the life history of the fish and as the fish length changes (Frost and Lowry, 1981;Hare and Cowen, 1995).…”

Formation of a Stress-Induced Check Mark on the Otoliths of Juvenile Fishes: Implications for Mesocosm Studies

“…Paperno et al (1997) examined another sciaenid, juvenile weakfish Cynoscion regalis and found that increment widths stabilized within a week of experimental manipulation. Additionally, an independent assessment of increment width formation in freeranging fishes at the conclusion of in situ experiments ally under stressful conditions), limiting the reliability of daily increment widths to accurately reflect recent patterns in daily growth (Secor et al 1989, Mugiya andTanaka 1992). Because we did not measure fish length prior to experimentation (in an attempt to reduce handling stress), this assumption remains untested and may limit conclusions drawn from the results regarding growth responses to habitat variables.…”