Breeding and larval rearing of threatened, endemic fish stonesucker, Garra ceylonensis (Bleeker)

Abstract

This study was aimed to develop captive breeding and nurture the young of stonesucker (Garra ceylonensis, Bleeker), a small threatened freshwater fish species endemic to Sri Lanka. Breeding of stonesucker was possible under indoor conditions without hormonal stimulation. They were single spawners having a fecundity of 562±176 eggs per fish (total length of 7.9±0.6 cm) with an egg size of 770–1877 μm. Duration of development stages were, egg to hatchling 36–48 h, hatchling to postlarva stage 3–4 days, postlarva to juvenile stage 5–64 days and adult stage in 300–365 days at 26–28°C. Juveniles exhibited bottom dwelling habit in 70–75 days. Postlarva fed with formulated feed exhibited the highest growth (P<0.05) compared with live diets, Artemia and microworm (Anguillula sp.). Although the juveniles revealed a significantly high growth performance (P<0.05) with swine liver diet up to day 45 compared with formulated feed and combination of detritus and plankton, formulated feed exhibited an increase in growth from day 50. Therefore, formulated feed could be used for rearing of postlarva and juvenile stages without any live feeds.

Study design considerations for assessing the health of fish populations impacted by agriculture in developing countries: a Sri Lankan case study

“…The Ceylon Stone Sucker (G. ceylonensis Bleeker 1863) is a small, freshwater benthic fish species that inhabits lotic environments with fast flowing water and has a maximum age of 4-5 years. Previous studies had been reported that G. ceylonensis is a single spawner, 67,68 and it is reported to mature at a size of 7-9 cm at an age of <2 years, 67,68 similar to the results found. Spawning had been reported in July 73 and December to March in Sri Lanka, with adhesive eggs being deposited on stony substrates.…”

“…The mean GSI for male R. daniconius was 3.8% (in September), and did not significantly different (Tukey test p > 0.05) between months, although maximum gonad size was recorded in July (4.5%); the maximum size in males often correlates with an early developmental size. 68 The regressions (r 2 ) of gonad weight and body weight were highly correlated in all months (p < 0.01). Probably, male R. daniconius may be sexually active throughout the year as shown with other fish species, including the tinfoil barb, Puntius schwanenfeldii.…”

“…It helps to examine whether fish are synchronous in their development (Table 6) and whether species show variability across sizes, and to examine the seasonality of the response. 68,122 For tropical fishes, drastic environmental fluctuations are unlikely and therefore multiple and protracted spawning events may be common, 64,70,80,81 which can challenge developing sensitive designs.…”

General Ecology and Habitat Selectivity of Fresh Water Fishes of the Rawan Oya, Kandy, Sri Lanka

“…Garra Ceylonensis and Schistura notostigma were recorded in significantly higher numbers in riffles of the stream compared to other two habitat types. These two are usually found in shallow, fast flowing water, especially of streams of the central hills at higher elevations (Sundarabarathy et al, 2005;Costa and Fernando, 1967). In our survey, this species was recorded from riffles of upper parts of the stream in high frequencies confirming the above fact.…”

“…In fact, only G. ceylonensis and S. notostigma occur in the uppermost areas, especially over 1000m elevation, where the temperature range is between 18.5 and 19.0 0 C and relatively high dissolved oxygen availability, where the optimal temperature prevails for these species. These two species are well adapted to live in rapidly flowing water with their subterminal suctorial mouth using which the fish attach to the rocks and feed on the algae grown on it (De Silva, 1991;Sundarabarathy et al, 2005). The absence of a preferred substrate may be the reason for these species being low in abundance in pools, which consists of sands and mud at the bottom.…”