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

Abstract

Juveniles of pejerrey, Odontesthes bonariensis, were exposed to 0.1% Alizarin Red S (ARS) alone or with a previous immersion in 2.2% saline solution (Osmotic Induction, OI) to enhance the ARS marking method. Fish were marked in the field and immediately released in 1 m 3 cages in "La Salada de Monasterio" lagoon, Chascomús, Buenos Aires, Argentina. After 73 days, clear marks were observed in the otoliths, caudal fin rays and scales with both treatments, being the intensity of the signal in the scales of OI+ARS treated fish higher. On the other hand, no marks were observed in the control group on the same structures. Approximately one year post-treatment (385 days), only marks in caudal fin rays were found clearly in OI+ARS treated fish. After this period, no significant differences in total length or weight between marked or control fish were observed and the mortality ranged between 30-40 % in all cages. These results provide strong evidence for the potential applicability of this cost-effective marking technique in differentiation of wild and hatchery-produced pejerrey. The success in the caudal fin rays marking is also important because it is easy to do and does not require the sacrifice of fish.Juvenis de pejerrey, Odontesthes bonariensis, foram expostos a Vermelho de Alizarina S (ARS) 0,1% de duas formas, sozinho ou com uma imersão anterior em 2,2% de solução salina (Indução osmótica, IO) para melhorar o método de marcação ARS. Os procedimentos foram realizados no campo e os peixes foram liberados em gaiolas (tanques-rede) de 1 m 3 na lagoa "La Salada de Monasterio", Chascomús, Buenos Aires, Argentina. Após 73 dias, marcas claras foram observadas nos otólitos, raios da nadadeira caudal e escamas em ambos os tratamentos, sendo que a intensidade do sinal nas escalas de IO + ARS de peixe tratado foi superior. Por outro lado, não foram observados marcas no grupo controle sobre as mesmas estruturas. Aproximadamente um ano pós-tratamento (385 dias), apenas marcas nos raios da nadadeira caudal foram encontrados claramente nos peixes tratados com IO+ARS. Entre os peixes observados, após este período, não houve diferenças significativas no comprimento total ou peso entre o grupo controle e marcados, ademais, a mortalidade variou entre 30-40% em todas as gaiolas. Estes resultados fornecem fortes evidências e um grande potencial para aplicação desta técnica rentável de marcação que diferencia o pejerrey selvagem e o produzido em cativeiro. O sucesso na marcação dos raios da nadadeira caudal também é de grande importância, pois sua verificação é fácil e não requer o sacrifício de peixes.

Two chemical marking procedures with Alizarin Red for piavaLeporinus obtusidens(Valenciennes, 1837) juveniles

“…Chemical compounds that combine with calcified tissues can produce detectable marks in scales, otoliths and other calcified structures, which are fluorescent when exposed to ultraviolet light (Liu et al., ). Many of these dyes, such as oxytetracycline (Abreu, Arantes, Hermes‐Silva, & Zaniboni‐Filho, ; Taylor, Fielder, & Suthers, ), calcein (Logsdon & Pittman, ), and alizarin (Campanella, Gárriz, Colautti, Somoza, & Miranda, ; Partridge et al., ), have been tested on fish. The dyes can be administered by immersion baths, thereby minimizing stress and mortality, diminish handling, and permit the simultaneous marking of a large number of small fish.…”

“…The complete marking of larval and juvenile fish was obtained using 200–300 mg ARS/L in 12–24 hr immersion baths (Beckman and Schulz, ) or using 100 mg ARS/L for tilapia Oreochromis niloticus during immersion baths of 12 hr (Ibáñez et al., ). Moreover, the use of an osmotic induction prior to treatment with the fluorochrome dye is an option to make chemical marking not only simple, but quick and economically effective, allowing reduction of the contact time between fish and dye solution, thereby facilitating the logistics and reducing the operational costs (Campanella et al., ; Crook, Mahony, Gillanders, Munro, & Sanger, ; Mohler, ). It is proposed to submit fish to short immersion baths in a saline solution before immersion in the fluorochrome solution, thereby greatly shortening the dye absorption time compared to that of conventional marking methods (Mohler, ).…”

“…It is proposed to submit fish to short immersion baths in a saline solution before immersion in the fluorochrome solution, thereby greatly shortening the dye absorption time compared to that of conventional marking methods (Mohler, ). Fish marking studies using previous osmotic induction in short immersion baths suggest the use of at least 1 g of dye per liter of water, independent of the fluorochrome dye (Campanella et al., ; Crook et al., ; Mohler, ).…”

Influence of pejerreyOdontesthes bonariensis(Valenciennes, 1835) broodstock age on gamete quality, reproductive performance and plasma sex steroid levels during the spawning season

“…Despite the importance of this fish species, pejerrey aquaculture is employed only to repopulation of wild stocks (Somoza et al . ; Campanella, Gárriz, Colautti, Somoza & Miranda ). Two of the major difficulties for its cultivation are the low production of eggs per spawning and the lack of spawning synchrony among females (Somoza et al .…”

“…Although, it should be noted, that the increase in the daylight length also promotes pejerrey reproduction (Miranda, Str€ ussmann & Somoza 2009). Despite the importance of this fish species, pejerrey aquaculture is employed only to repopulation of wild stocks (Somoza et al 2008;Campanella, G arriz, Colautti, Somoza & Miranda 2013). Two of the major difficulties for its cultivation are the low production of eggs per spawning and the lack of spawning synchrony among females (Somoza et al 2008).…”