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Validation of daily increments in otoliths of northern squawfish larvae

January 1, 1998

Otoliths from laboratory-reared northern squawfish, Ptychocheilus oregonensis, larvae were examined to determine the periodicity of increment deposition. Increment deposition began in both sagittae and lapilli after hatching. Reader counts indicated that increment formation was daily in sagittae of 1-29-day-old larvae. However, increment counts from lapilli were significantly less than the known ages of northern squawfish larvae, possibly because some increments were not detectable. Otolith readability and age agreement among readers were greatest for young (<11 days) northern squawfish larvae. This was primarily because a transitional zone of low-contrast material began forming in otoliths of 8-11-day-old larvae and persisted until approximately 20 days after hatching. Formation of the transition zone appeared to coincide with the onset of exogenous feeding and continued through yolk sac absorption. Our results indicate that aging wild-caught northern squawfish larvae using daily otolith increment counts is possible.

Citation Information

Publication Year 1998
Title Validation of daily increments in otoliths of northern squawfish larvae
Authors R.H. Wertheimer, C.A. Barfoot
Publication Type Article
Publication Subtype Journal Article
Series Title California Fish and Game
Series Number
Index ID 70020780
Record Source USGS Publications Warehouse
USGS Organization