The effects of surgically implanted dummy tags on the survival, growth performance, and physiology of pikeperch (Sander lucioperca).

The aim of this work was to determine the impact of surgically implanted telemetry transmitters (TTs) on the growth, survival, hematological and biochemical indexes, and wound healing in juvenile pikeperch (Sander lucioperca) (body weight 60-90 g). Two incision suturing methods were used-silk sutures (experiment I-group ST) or tissue adhesive (experiment II-group GT). After tagging, the fish were held in a recirculating system for 35 days. No statistically significant differences were noted in the growth or condition indexes analyzed among the fish tagged with TT compared with those from the control groups (untagged). Substantial individual variability was noted, however, in the parameters examined in both the control and tagged groups. Among the hematological indexes, statistically significant differences were only noted in experiment I. Lower values of mean corpuscular volume and mean corpuscular hemoglobin were noted in group ST. Among the biochemical parameters, creatinine was statistically significantly threefold lower, magnesium and alkaline phosphatase (ALP) levels were lower, and ammonia levels were higher in group ST than in the control group. In experiment II, significant differences were only noted for ALP. Tissue adhesive was the superior and more effective method for closing the incision after TT implantation in juvenile pikeperch. This type of suturing facilitated faster healing, and it had less of an impact on juvenile pikeperch welfare.

Salinity does not alter the effectiveness of menthol as an anesthetic and sedative during the handling and transport of juvenile fat snook (Centropomus parallelus) / Salinidade não altera a eficácia de mentol como um anestésico e sedativo durante a manipulação e transporte de juvenis de robalo peva (Centropomus parallelus)

Abstract The effectiveness of menthol as anesthetic and sedative for fat snook (Centropomus parallelus) was tested at different salinities. In the first experiment, the fish were exposed to different concentrations of menthol (25, 37 and 50 mg L–1) in water at different salinities (0, 17 and 36 ppt). In the second experiment, the fish were transported for 10 hours in water with menthol at concentrations of 0, 3.7 and 7.4 mg L–1 under different salinities. Na+ and K+ ions from fish body and water were analyzed after transport. The optimal concentrations of menthol for a short handling period and surgical induction was 37 and 50 mg L–1, respectively, and these values were independent of salinity. After transport, neither mortality nor significant changes in ammonia or dissolved oxygen were observed between treatments at the different salinities. The nitrite levels were lower in freshwater than in brackish and saltwater, but did not change with mentol. The total body levels of Na+ increased with the salinity increase. Menthol is an effective anesthetic for handling of juvenile fat snook at different salinities. Menthol did not influence the measured water parameters and body ions, and it is not necessary for the transport of fat snook.

Resumo A eficácia de mentol como anestésico e sedativo para o robalo peva (Centropomus parallelus) foi testada em diferentes salinidades. No primeiro experimento, os peixes foram expostos a diferentes concentrações de mentol (25, 37 e 50 mg L–1) em diferentes salinidades na água (0, 17 e 36 ppt). No segundo experimento, os peixes foram transportados por 10 horas em água com mentol nas concentrações de 0, 3,7 e 7,4 mg L–1 sob diferentes salinidades. O Na+ e K+ do corpo do peixe e a água foram analisados após o transporte. As concentrações ideais de mentol para um período curto de manipulação e indução cirúrgica foi 37 e 50 mg/L, respectivamente, sendo esses valores independentes da salinidade da água. Após o transporte, não foi verificado mortalidades e nem alterações significativas nos níveis da amônia e oxigênio dissolvido entre os tratamentos para as diferentes salinidades. Os níveis de nitrito foram mais baixos em água doce do que em água salobra e água salgada, mas não se alterou com o mentol. Os níveis corporais de Na+ e K+ aumentaram com o aumento da salinidade. Mentol é um eficaz anestésico para manipulação de robalo peva juvenil em diferentes salinidades. Mentol não influenciou os parâmetros de medição de água e íons do corpo, e não é necessário para o transporte de robalo peva.

Assessing the suitability of a non-lethal biopsy punch for sampling fish muscle tissue.

Samples for the analysis of stable isotopes, genetics and other tissue sampling methods of small fish are often taken via lethal techniques. The aim of this study was to determine the suitability of a non-lethal sampling method for removing muscle tissue from fish under 30 cm total length (TL). A 4-mm biopsy punch was used to remove muscle tissue from two different species, Lutjanus russelli (Lutjanidae) and Lethrinus laticaudis (Lethrinidae). Several scales were removed from the sampling location, and then the biopsy punch was inserted to remove the muscle tissue. Immediately following this, a mixture of Fish Bandage™ and three drops of Betadine™ antiseptic solution was applied to the wound to reduce the chance of infection. The biopsy punch removes an average of 8 mg of muscle tissue from the fish, more than is required for stable isotope and genetic analyses (1 mg). The condition of fish subjected to our three treatments, biopsied fish, a handling controls and a tank control, was compared via gill beat counts at the time of biopsy and 3, 6, 9, 12 and 24 h after treatment. Overall, no instances of mortality were recorded across the study for all species and all treatments. This method has been found to be a suitable non-lethal method in the removal of muscle tissue from these two fish species, potentially also other species under 30 cm TL, by eliminating mortality and minimising stress responses in sampled fishes.

Salinity does not alter the effectiveness of menthol as an anesthetic and sedative during the handling and transport of juvenile fat snook (Centropomus parallelus).

The effectiveness of menthol as anesthetic and sedative for fat snook (Centropomus parallelus) was tested at different salinities. In the first experiment, the fish were exposed to different concentrations of menthol (25, 37 and 50 mg L-1) in water at different salinities (0, 17 and 36 ppt). In the second experiment, the fish were transported for 10 hours in water with menthol at concentrations of 0, 3.7 and 7.4 mg L-1 under different salinities. Na+ and K+ ions from fish body and water were analyzed after transport. The optimal concentrations of menthol for a short handling period and surgical induction was 37 and 50 mg L-1, respectively, and these values were independent of salinity. After transport, neither mortality nor significant changes in ammonia or dissolved oxygen were observed between treatments at the different salinities. The nitrite levels were lower in freshwater than in brackish and saltwater, but did not change with mentol. The total body levels of Na+ increased with the salinity increase. Menthol is an effective anesthetic for handling of juvenile fat snook at different salinities. Menthol did not influence the measured water parameters and body ions, and it is not necessary for the transport of fat snook.

Evaluation of dorsal aorta cannulation for immunological studies of grouper (Epinephelus malabaricus).

Blood is often withdrawn to study the immune responses of fish. However, netting, handling and anaesthetising the experimental fish, and drawing blood samples cause severe stress that may alter the effects of immune study protocols and treatments. We evaluated the effect of aorta cannulation, for use in immune studies, on grouper (Epinephelus malabaricus) plasma cortisol, total red and white blood cell counts and phagocytosis. Plasma cortisol increased from 30 to 88 ng/ml 1 day after insertion of the cannula, to a maximum of 951 ng/ml 3 to 5 days after surgery, indicating the groupers were stressed by cannulation and post-cannulation inflammation. Total RBC count decreased, and total WBC count increased after surgery. Following cannulation, the phagocytic index of peripheral blood leukocytes decreased from 100% to 46%. The adverse effects of cannulation were mitigated by continuously immersing groupers in oxytetracycline (OTC), which decreased the recovery period for treated fish. In contrast, OTC-treatment did not markedly improve the recovery of groupers subjected to caudal vessel puncture. Cortisol levels in OTC-treated grouper with caudal vessel puncture were significantly higher than in OTC-treated, cannulated grouper, and remained at a high level until day 13 of the experiment. From day 7 to 13, total RBC and WBC counts in OTC-treated, cannulated groupers were significantly different from those in OTC-treated groupers with caudal vessel puncture. OTC treatment improved the phagocytic index of groupers subjected to caudal vessel puncture, but the phagocytic index was lower than that of groupers subjected to cannulation. Cannulation minimises visual and handling disturbances, and facilitates standardisation of experimental conditions and quick and easy sampling via the dorsal aorta cannula. Therefore, dorsal aorta cannulation minimises the stress of blood sampling and should prove useful for immune studies in fish.

Orbital exenteration and placement of a prosthesis in fish.

OBJECTIVE: To develop a procedure for orbital exenteration and prosthesis placement in fish. DESIGN: Prospective study. ANIMALS: 5 cultured hybrid striped bass (Morone saxatilis x M chrysops) ranging from 30 to 50 cm in length. PROCEDURE: Exenteration was performed, using a dorsal approach in which blunt dissection was performed in the circumorbital sulcus. The orbit was then dried, and simple interrupted sutures were placed, leaving 2 suture loops within the orbit. The orbit was filled with polyvinylsiloxane, and a prosthetic glass eye was seated in the polyvinylsiloxane. RESULTS: All fish retained the prosthesis and had satisfactory cosmetic results at the end of the 8-week study period. CLINICAL IMPLICATIONS: The increase in popularity of pet fish and abundance of valuable aquarium and show fish have led to heightened awareness of piscine ocular disease. Aquarium fish are often euthanatized because of disfiguring ocular problems. The technique described here for surgical exenteration and cosmetic orbital prosthesis placement in fish may extend the captive life of public display fish.