Growth estimates from otolith increment widths of juvenile chinook salmon (Oncorhynchus tshawytscha) reared in changing environments

Abstract

For otolith increments to provide useful estimates of fish growth, otolith growth must covary closcly with somatic growth. We reared groups of juvenile chinook salmon (Onrorhynrhus rshayvrschu Walbaum) for 70 days, changing ration or temperature during a 20-day treatment period. Restricted rations halted somatic growth, however increment widths decreased gradually; somatic growth was overestimated from increment width. Otolith growth followed changes in water temperature more closely than changes in ration, supporting a hypothesized effect of metabolic rate on otolith growth. Increment growth was only loosely coupled to fish growth rate, and may also be affected by past growth histories. For juvenile fish, increment widths may not be sensitive indicators of short-term changes in growing conditions.

Juvenile Chinook salmon (Oncorhynchus tshawytscha) growth in off-channel and main-channel habitats on the Sacramento River, CA using otolith increment widths

“…We quantified juvenile salmon somatic growth by measuring daily otolith increment widths. While water temperature can decouple otolith growth from somatic growth and complicate otolith microstructure interpretation (Marshall and Parker 1982;Mosegaard et al 1988;Bradford and Geen 1992), otolith growth cannot be predicted by water temperature alone. To investigate the effect of temperature on otolith increment widths, Gauldie (1991) reared juvenile Chinook salmon at five different water temperatures (8°C, 10°C, 12°C, 14°C, and 16°C) and fed them to repletion.…”

“…Prey item identification followed Merritt and Cummins (1996) and Borror et al (1992). Aquatic insect larvae and pupae were identified to scientific family, while aquatic adult insects, terrestrial insects, and crustaceans were identified to scientific order.…”

“…We can use these daily otolith growth increments to compare growth differences across a variety of habitats. One early concern with otolith analysis was that increment widths might be more influenced by temperature and metabolism than by somatic growth (Neilson and Geen 1982;Mosegaard et al 1988;Wright et al 1990;Bradford and Geen 1992). While otolith growth can become uncoupled from somatic growth under specific conditions (e.g.…”

Otolith Microstructure in Young-of-the Year Dolly Varden, <i>Salvelinus malma</i>, from American and Asian Populations: Resolution of Comparative Life History Characteristics

“…Otolith radius-fish length regressions may, however, be more conservative (Radtke, 1989(Radtke, , 1990. It has also been suggested that otolith growth may be controlled more directly by metabolic rate than by somatic growth (Bradford and Geen, 1992;Wright et al, 1991).…”

Larval condition and growth of <i>Sardinella brasiliensis </i> (Steindachner, 1879): preliminary results from laboratory studies

“…Microstructural growth patterns in otoliths of teleost fish and age validation studies of larval and juvenile otoliths have shown that microstructural characteristics are species-specific and may be influenced by nutrition and environmental variables (Campana and Neilson, 1985;Jones, 1986;Maillet and Checkley, 1989;Bradford and Geen, 1992). Recent reports on the relationship between daily somatic growth and incremental growth of otoliths support the use of increment widths as a measure of daily somatic growth (Secor and Dean, 1989;Hovenkamp, 1989Hovenkamp, , 1990Moksness and Fossum, 1991).…”