NOTE Kirshenbaum et al A study of tagging methods for Cucumaria frondoso 



301 



Results and discussion 



Tagging method 



Fluorescent dyes 



Double T-bar tags 

 Double-pass 

 Long tag (91 

 Short tag (151 



Control 

 Tagging gun puncture 



Total 



The tagging stu(iy was suc- 

 cessful in providing infor- 

 mation on retention rates 

 for the different tagging 

 methods observed during 

 the 140 days of the investi- 

 gation (Fig. 2). Fluorescent 

 dye injections and single- 

 anchor long T-bar tags were 

 the most successful means 

 identified in tagging sea 

 cucumber in the waters off 

 Maine. Eighty percent with 

 dye continued to fluoresce 

 under the UV light and 65% 

 of single-anchor long T-bar 

 tags remained embedded in 

 the sea cucumbers at the 

 end of the investigation on day 140. The T-bar 

 method may be the most practical for short-term 

 research on this species considering the time 

 and expense of fluorescent dye injection. Another 

 advantage over injections is that the tagging 

 gun technique is much more easily repeatable 

 among subjects, whereas the site of injection 

 varied among animals depending on the loca- 

 tion of soft tissue. 



Double-pass T-bar tags were expelled faster 

 than those in the single-anchor condition. With 

 the double-pass tag, it appeared that the long 

 portion of the tag under the animal's epidermis 

 gradually moved upward until it was expelled 

 outside of the skin without scarring the animal. 

 The longer bars were pushed out the fastest 

 and all were shed before day 50. Shorter T-bar 

 tags took almost twice as long to reach 0% re- 

 tention as the longer T-bars in the double-pass 

 condition, perhaps because the shorter bars 

 pinched the dermis tightly between tag bars, 

 whereas animals with the longer bars were 

 able to relax their entire body wall. After tags 

 were shed in all T-bar conditions, it was not 

 possible to tell which experimental condition 

 each individual had experienced. No mortality 

 was observed from the tags or from the control 

 punctures. 



Five T-bar tagged animals experienced a punctured 

 respiratory tree caused by the tagging gun. The respi- 

 ratory tree is an internal organ used for breathing by 

 pumping seawater in and out. After the initial puncture, 

 no trace of the injury could be detected and no differ- 

 ences in appearance or behavior were noted throughout 

 the investigation. Although it was not possible to track 

 which individuals had a partially punctured respiratory 

 tree, injured individuals may have shed tags at a differ- 

 ent rate than others in their cohorts. Internal injuries 

 may also have affected the results of later studies of 

 growth and movement with the use of manual tags. 



Table 1 



Tagging study design for the sea cucumber Cucumaria frondosa off Maine. Total num- 

 bers sampled for each method are indicated as total animals in the right column. Paren- 

 theses identify the number of animals sampled. 



Total animals 



10 



Single-anchor 

 Long tag 

 Short tag 



45 



(6) 

 (15) 



Double-puncture (9) Single-puncture (6) 



15 



70 



- double-pass long 



 single-anchor long 



 double-pass short 



- single-anchor short 



- florescent dye 



- pooled 



25 50 75 100 125 150 



Number of days after tagging 



Figure 2 



Tagging retention in the sea cucumber Cucumaria frondosa for 

 individual-style tags over 140 days of observation in the waters 

 off Maine. Note that florescent dye and single-anchor long T-bar 

 tags were the most successful methods identified. 



With the use of a largest possible sample size and care- 

 ful placement of the tagging gun, this potential bias can 

 be minimized. Additionally, it is important to consider 

 that tag retention rate in the field may vary more than 

 results observed in the laboratory. 



We believe that the fluorescent dye injections and 

 single-anchor long-T-bar tagging methods in our in- 

 vestigation will likely prove effective for a longer-term 

 study with additional preliminary tagging analysis. 

 However, a more effective way to study the growth 

 of sea cucumbers may be the combination of caging 

 and tagging, where tagged individuals of similar size 

 are put in the same cage to monitor a change in size. 



