Retention and Nonlethal External Detection of Calcein Marks in Rainbow Trout and Chinook Salmon

Abstract

An osmotic induction method was used to apply calcein marks to Chinook salmon Oncorhynchus tshawytscha and the Kamloops strain of rainbow trout O. mykiss (both migratory strains used for stocking into tributaries of Lake Superior). Preliminary exposure to a saline solution followed by immersion in a 0.5% calcein solution encouraged rapid infusion of calcein into fish tissues. Four‐month‐old Chinook salmon were exposed to a 1.5% or 5.0% salt solution to evaluate tolerance of different salinities and effects on mark intensity and retention. Rainbow trout were marked at three ages (2 weeks, 3.5 months, and 16 months posthatch) to evaluate the effects of age at treatment on mark intensity and long‐term retention (a 5.0% preliminary salt bath was used). External detection of marks in scales, head, and fin rays was accomplished with a hand‐held detector. The marking technique we used was well tolerated by both Chinook salmon and rainbow trout, and marks persisted into adulthood for rainbow trout treated at 3.5 months posthatch or later. The 5% salt concentration resulted in the persistence of more intense marks than did the 1.5% salt concentration. We demonstrated the potential applicability of calcein marks for instream population studies of migratory or anadromous species treated as fry or for studies involving release of post‐fry‐stage migratory or anadromous fish intended for recapture as adults.

Review of Marking Methods and Release-Recapture Designs for Estimating the Survival of Very Small Fish: Examples from the Assessment of Salmonid Fry Survival

“…For example, stream-specific strontium isotopic ratios have been used to study Atlantic salmon in tributaries of the Connecticut River (Kennedy et al, 2002). Calcein marks have been studied in both Atlantic salmon (Mohler et al, 2002;Honeyfield et al, 2006) and rainbow trout (Bart et al, 2001;Frenkel et al, 2002;Negus and Tureson, 2004), as well as in brook trout (∼1 g; Honeyfield et al, 2006).…”

“…Other studies suggest that the effect of PIT tags on survival may be both size-and species-dependent (Acolas et al, 2007) or dependent on tagger experience. Retention of internal marks ranges from 4-16 months for chemical markers using calcein immersion (Frenkel et al, 2002;Mohler, 2003;Negus and Tureson, 2004), to over 21 months using a strontium chloride marker (Schroder et al, 1995), to permanent retention for strontium isotopic ratios (Kennedy et al, 2002) and thermal otolith marking (Brothers, 1990;Buckley and Blankenship, 1990). Some chemical markers fade on exposure to direct sunlight (e.g., calcein immersion; Johnson, 2003), and a general positive relationship was found between mark endurance and fish size for chemical marking of small rainbow trout (∼0.2-0.3 g; Bart et al, 2001;Frenkel et al, 2002).…”

Evaluation of marking efficiency of different alizarin red S concentrations on body fish structures in <i>Oreochromis niloticus</i> (Perciformes: Cichlidae) juveniles

“…As a consequence of exposing the tilapia to high salinity water, the fish cells loose a certain amount of water. When the tilapias return to the ARS solution, the consequential osmotic differences resulted in the rapid uptake of dye, as water was replaced via osmosis through the skin and gills (Mohler 2003); this generated an efficient utilization of dye independently of the ARS concentrations, and the reduction in immersion time (Mohler 2003, Negus & Tureson 2004 and high-quality marks (Crook et al 2007). Nevertheless, osmotic induction marking with ARS produced more mortality than the 12-hour immersion treatment; we do not discard that lower salt immersion times might produce less mortality.…”

Osmotic induction marking with Alizarin Red S on juveniles of pejerrey, Odontesthes bonariensis (Atherinopsidae)

“…Among these methods, chemical immersion of fish in a solution that contains a fluorescent dye has been used to mark internal calcified structures, such as otoliths (Brooks et al, 1994;Skov et al, 2001;van der Walt & Forager 2003). Similar procedures have also resulted in the obtention of external marks, which allowed for a non-invasive detection (Mohler, 2003;Bashey, 2004;Negus & Tureson, 2004). The most commonly used were oxytetracycline (OTC), hydrochloride, calcein, alizarin complexone (AC) and alizarin red S (ARS).…”