Coded wire tagging of juvenile curimbatá, Prochilodus lineatus (Valenciennes, 1837) (Characiformes): mortality, tag retention, and growth

In recent decades, Brazilian hydroelectric reservoirs have been stocked with hundreds of millions of juvenile migratory fish, but almost no research on stocking has been conducted. In order to study stocking it is essential to tag the fish to be stocked. In this investigation we determined handling-induced mortality, tag retention rate, and absolute growth rate of hatchery-reared juvenile curimbatá (Prochilodus lineatus) tagged with coded wire tags (CWT), a tag widely used on stocked fish. We injected CWT into the dorsal musculature just below the first dorsal fin ray. Despite the need for frequent tag injector maintenance, this tagging location proved to be suitable for tagging juvenile curimbatá. We found no short-term mortality of juvenile curimbatá handled for CWT tagging, high retention rate for CWT (≥ 98.2%) even after 174 d of tagging, and no influence on absolute growth rate by CWT. We conclude that CWT is effective at tagging juvenile curimbatá, and we expect that it will also be effective for many other Brazilian fish species used for stocking

Effect of anesthetic, tag size, and surgeon experience on postsurgical recovering after implantation of electronic tags in a neotropical fish: Prochilodus lineatus (Valenciennes, 1837) (Characiformes: Prochilodontidae)

ABSTRACT Implantation of telemetry transmitters in fish can be affected by different parameters. This study aimed to evaluate the effect of type of anesthetic, tag size, and surgeon experience on surgical and postsurgical wound healing in the neotropical fish Prochilodus lineatus . In total, eighty fish were surgically implanted with telemetry transmitters and forty fish were kept as controls. Forty fish were implanted with a small tag and other forty were implanted with a large tag. Similarly, forty fish were anesthetized with eugenol and forty fish were anesthetized by electroanesthesia, and forty surgeries were performed by an expert surgeon and forty surgeries were performed by novice surgeons. At the end of the experimental period seventeen (21.3%) tagged fish had postsurgical complications, including death (1.3%), tag expulsion (2.5%), antenna migration (2.5%), and infection (15%). Tag size was the key determinant for postsurgical complications. Surgical details and postsurgical wound healing were not affected by type of anesthetic. Incision size, duration of surgery, and wound area were significantly affected by tag size and surgeon experience, and the number of sutures was significantly affected by tag size only. The results indicate that successful implantation of telemetry transmitters is dependent upon surgeon experience and tag size

Induced spawning and early ontogeny in hatchery-reared catfish Zungaro jahu (Siluriformes: Pimelodidae)

Hatchery-kept catfish jahus Zungaro jahu (Ihering, 1898) were induced to spawn with carp pituitary extract. The telolecithal eggs were round (1.6 ± 0.1 mm in diameter), demersal, free, and covered with a 0.4 mm-thick jelly coat. The gonadosomatic index of 2.8 was comparable to that of other Pimelodidae. The number of eggs x g of ova-1 was 804 ± 144. Hatching occurred 14.5 h after fertilization, at a temperature of 27.3 ± 0.4º C. The newly-hatched embryos measured 3.9-4.3 mm of total length (TL). At 18 h post-hatching (HPH; 5.3 ± 0.1 mm TL), the retina was pigmented, the mouth opened and dorsoflexion of the notochord had initiated. At 36 HPH (6.4 ± 0.2 mm TL), fusiform chromatophores were vertically arranged in the primordial fin fold and the notochord was dorsoflexed. The yolk sac was almost exhausted by 48 HPH (7.3 ± 0.2 mm TL). At 128 HPH (8.6 ± 0.6 mm TL) the pectoral, dorsal, adipose, caudal, anal, and pelvic fins were readily observable whereas the primordial fin fold was no longer visible. At 224 HPH (16.6 ± 2.5 mm TL), the metamorphosis was completed and the larvae had acquired the juvenile appearance

Induced spawning and early ontogeny in hatchery-reared catfish Zungaro jahu (Siluriformes: Pimelodidae)

Hatchery-kept catfish jahus Zungaro jahu (Ihering, 1898) were induced to spawn with carp pituitary extract. The telolecithal eggs were round (1.6 ± 0.1 mm in diameter), demersal, free, and covered with a 0.4 mm-thick jelly coat. The gonadosomatic index of 2.8 was comparable to that of other Pimelodidae. The number of eggs x g of ova-1 was 804 ± 144. Hatching occurred 14.5 h after fertilization, at a temperature of 27.3 ± 0.4º C. The newly-hatched embryos measured 3.9-4.3 mm of total length (TL). At 18 h post-hatching (HPH; 5.3 ± 0.1 mm TL), the retina was pigmented, the mouth opened and dorsoflexion of the notochord had initiated. At 36 HPH (6.4 ± 0.2 mm TL), fusiform chromatophores were vertically arranged in the primordial fin fold and the notochord was dorsoflexed. The yolk sac was almost exhausted by 48 HPH (7.3 ± 0.2 mm TL). At 128 HPH (8.6 ± 0.6 mm TL) the pectoral, dorsal, adipose, caudal, anal, and pelvic fins were readily observable whereas the primordial fin fold was no longer visible. At 224 HPH (16.6 ± 2.5 mm TL), the metamorphosis was completed and the larvae had acquired the juvenile appearance