Optimising chemical marking techniques for Australian bass, Macquaria novemaculeata, fry and fingerlings prior to restocking

Abstract

Many stocking programs are performed without any subsequent assessments to determine the survival of the stocked fish, often due to the difficulties in distinguishing stocked from wild fish. A series of optimisation trials were undertaken to determine the suitability of calcein (2,4-bis-[N,N′–di(carbomethyl)-aminomethyl]fluorescein) for chemically marking hatchery-reared Australian bass, Macquaria novemaculeata (Steindachner), fry and fingerlings. The technique was optimised by trialling immersion times for salt (2.5 or 5 min), calcein concentrations (0.5 or 1%) and calcein immersion times (5 or 10 min). A general-purpose modulated probe fluorometer was used as a non-lethal detection method to establish mark retention and distinguish between calcein-marked and unmarked fish. Five minutes of saline immersion, followed by 10 min of calcein immersion at a calcein concentration of 1% was the optimal marking method. Growth and survival of fish was not affected as a result of any of the calcein-marking methods. It is therefore effective to calcein-mark Australian bass fry and fingerlings before stocking and to non-lethally detect marked individuals using a field-portable meter to assist in the assessment of stocking programs. Findings from this study may also reflect the potential use of calcein to chemically mark fry and fingerlings of other fish species.

Direct Age Determination of a Subtropical Freshwater Crayfish (Redclaw, Cherax quadricarinatus) Using Ossicular Growth Marks

“…One commonly used validation method involves applying chemical stains that produce a known-date artificial mark, with subsequent growth being assessed over an annual cycle [ 1 , 4 ]. Calcein is a fluorescent dye that is effective for marking numerous ageing structures [ 13 – 14 ] and was used to tag American lobster ( Homarus americanus ) for up to six months [ 8 ].…”

Efficacy of fluorescent calcein mark retention and identification in endangered Colorado pikeminnow Ptychocheilus lucius

“…Owing to global declines in fish populations, the need to estimate hatchery contributions to natural populations will be ever‐increasing. Over the last few decades, calcein as a batch‐marking tool for fish has received considerable attention due to its ease of use and minimal effects on growth and mortality (Cameron et al, ; Crook et al, ; Leips et al, ; Lu, Fu, Zhang, Su, & Yao, ). However, given the current literature, managers may have difficulty understanding when calcein may or may not be an adequate marking tool for their needs.…”

“…Each observer also held a general‐purpose modulated probe fluorometer (GFP III by Opti‐Sciences Inc) against each operculum, while an experimenter recorded the reading (Crook et al, ). The GFP III fluorometer reports fluorescence in a range from zero to 1,800 units (maximum detectable limit), and the final value recorded for each fish was the larger of the two readings (Cameron et al, ).…”

“…Calcein, a fluorescent dye that bonds with calcium phosphate in ossified tissues, has been used as a batch‐marking tool across a number of species with limited effects on growth or mortality, regardless of life stage (e.g. Becker, Fielder, Lowry, & Taylor, ; Brooks, Heidinger, & Kohler, ; Cameron, Baumgartner, Bucher, & Robinson, ; Castillo et al, ; Honeyfield, Kindschi, Bell, & Mohler, ; Logsdon & Pittman, ; Mohler, ). However, calcein mark retention in fish released into the wild has been variable (Ingram, Hunt, Lieschke, Krusic‐Golub, & Giri, ) and often these inconsistencies have been attributed to photodegradation (Bashey, ).…”

Development of a Calcein Marking Technique for Juvenile Mulloway Argyrosomus japonicus to Be Used in Stock Enhancement Programs

“…Calcein marks are known to be retained over extended periods in freshwater fishes; for example, recaptured Golden Perch Macquaria ambigua still show visible marks on internal structures after 3.5 years (Forbes et al 2016). Captive studies have revealed similar results (Mohler 2003;Negus and Tureson 2004); however, the strength and characteristics of these marks can vary among species (Cameron et al 2011). Longer-term studies evaluating the retention of calcein stains by marine fishes over multiple years will be required to support the use of the mark for monitoring of released Mulloway.…”