Ling Cao

Responsible Aquaculture in 2050: Valuing Local Conditions and Human Innovations Will Be Key to Success

As aquaculture production expands, we must avoid mistakes made during increasing intensification of agriculture. Understanding environmental impacts and measures to mitigate them is important for designing responsible aquaculture production systems. There are four realistic goals that can make future aquaculture operations more sustainable and productive: (1) improvement of management practices to create more efficient and diverse systems at every production level; (2) emphasis on local decisionmaking, human capacity development, and collective action to generate productive aquaculture systems that fit into societal constraints and demands; (3) development of risk management efforts for all systems that reduce disease problems, eliminate antibiotic and drug abuse, and prevent exotic organism introduction into local waters; and (4) creation of systems to better identify more sustainably grown aquaculture products in the market and promote them to individual consumers. By 2050, seafood will be predominantly sourced through aquaculture, including not only finfish and invertebrates but also seaweeds.

Effects of the timing of initial feeding on growth and survival of spotted mandarin fish Siniperca scherzeri larvae

The effects of delayed first feeding on growth and survival of spotted mandarin fish Siniperca scherzeri larvae were examined under controlled conditions. Morphometric characters [yolk-sac volume, oil globule volume, head depth (H(D)), body depth (B(D)), eye diameter (E(D)), musculature height (M(H)), mouth diameter (M(D)) and total length (L(T))], body mass (M), specific growth rate (S(GR)) and survival were evaluated under different first-feeding time (2, 3, 4 and 5 days after hatching). Larvae began to feed exogenously at 2 days after hatching (DAH) and the point of no return (P(NR)) occurred between 5 and 6 DAH at 23 degrees C, range +/-1.0 degrees C. The yolk volume of larvae first-fed at 2 days had a significant difference compared with that of larvae first-fed at 3, 4 and 5 days on 3 and 4 DAH. The larvae first-fed at 2 days achieved comparatively better growth performance than that of 3, 4 and 5 days. On 5 DAH, all morphometric characters had significant differences between 2 and 5 days and 2 and 4 days initial feeding, respectively. Total mortality was recorded on 9 DAH for the larvae first-fed at 5 days. On 12 DAH, significant differences were observed between 2 and 4 days and 3 and 4 days initial feeding for all morphometric characters. From 16 DAH to the end of experiment, all growth variables of the larvae first-fed at 2 days were significantly higher than those in other treatments. The S(GR) (2-9 DAH) first-fed at 2 and 3 days were significantly higher than 4 and 5 day treatments, and the S(GR) (9-16 DAH) first-fed at 2 days was significantly higher than 3 and 4 day treatments. There was no significant difference, however, of S(GR) (16-28 DAH) among treatments. Survival rate was significantly higher at 2 days initial feeding (27.42%) when compared with 3 (15.96%) and 4 days (7.92%) initial feeding at the end of experiment. The present study suggests that the first feeding of S. scherzeri larvae should be initiated at 2 days after hatching for achieving good growth and survival.

Comparative and evolutionary analysis in natural diploid and tetraploid weather loach Misgurnus anguillicaudatus based on cytochrome b sequence data in central China

To obtain the phylogenetic relationship between diploid and tetraploid Misgurnus anguillicaudatus, the mitochondrial cyt b gene in the diploid and tetraploid weather loach were isolated and sequenced. The DNA sequences were analyzed using MEGA 3.0 software to determine the phylogenetic relationship. Forty-five variable sites among cyt b gene sequences and 18 amino acid substitutions occurred within the diploid and tetraploid loaches as deduced from the nucleotide sequences analysis of the cyt b gene. The nucleotide pairwise distance between diploid and tetraploid loach ranged from 0.001 to 0.025. Phylogenetic analysis revealed evolutionary relationships between diploid and tetraploid loach. Our results indicated a significant difference between diploid and tetraploid loach about the cyt b gene. AMOVA analysis indicated that there were no significant genetic variations within diploid loaches (Fst = 0.2529, P > 0.05) and within tetraploid loaches (Fst = 0.0564, P > 0.05), neither. However, significant genetic differences were found between diploid and tetraploid loaches (Fst = 0.7634, P < 0.05). Thus, it is concluded that no reproductive isolation was found within the same cytotypes of different localities, but there was reproductive isolation between these two cytotypes. The diploid loach existed before the tetraploid loach in nature. The present study is the first to describe the phylogenetic relationships of natural polyploidy weather loach using mtDNA cyt b gene.

Threatened fishes of the world: Trachidermus fasciatus Heckel, 1837 (Cottidae)

Common name: Roughskin sculpin. Conservation status: Not in IUCN Red List; Listed as critically endangered in Category II of the National Key Protected Wildlife List and in China Red Data book of Endangered Animals-Pisces (Yue and Chen 1998). Identification: D VIII-IX/18–20, A 16–18, P I/17–18; Pectoral fin fan-shaped; Caudal fin truncate. Depressed body; Head large; Mouth large; Protruding upper jaw and largest spine on pre-operculum; Pseudobranch present; No scale (Right to illustration held by Kim Ik-Soo). Distribution: Distributed along southern and western coasts of Korean Peninsula, eastern coast of China, and rivers flowing into Ariake Bay on Kyushu Island of Japan (Norio et al. 2002). Habitat and ecology: Benthic, catadromous and carnivorous, feeding on zooplankton, fish and shrimp. Juveniles occur in freshwater lakes and rivers; adults enter estuaries and sea during reproductive season. Euryhaline (0∼32‰) indicates flexibility for reproduction and early life (Kinoshita et al. 1999). Reproduction: Age at first maturity is 1 year. Spawning sites locate in intertidal zone with oyster reefs. When water temperature reaches 4–5°C, spawn in empty shells of oyster or bivalve during February to March (Takeshita et al. 1999). Eggs adhesive, 1.48∼1.58 mm in diameters. Absolute fecundity 5,100∼12,800 eggs∙fish (Wang 1999). Threats: Wild populations have seriously declined since 1970s mainly due to the destruction of natural habitats and spawning sites, as well as overfishing and lack of regulation for sustainable fisheries. Conservation action: China has established protected areas (Wendeng, Shandong province), and investigated habitat requirements. Japan and South Korea studied spawning nests, distribution and life history. Conservation recommendations: Since most populations disappear in traditional habitats (Zhuang et al. 2006), long term protection of the remaining population should be ensured. Industrial water in coastal areas should be treated before discharge and further research needed to access the feasibility of fish passage construction around dams. Environ Biol Fish (2009) 86:63–64 DOI 10.1007/s10641-007-9318-2

Threatened fishes of the world: Hucho bleekeri Kimura, 1934 (Salmonidae)

Conservation status, identification, distribution, habitat and ecology, reproduction, threats, conservation actions and recommendations of a critically endangered fish, Hucho bleekeri Kimura, which is endemic to China, was introduced.

Threatened fishes of the world: Schizothorax taliensis Regan, 1907 (Cyprinidae)

Common name: Dali schizothoracin. Conservation status: Endangered in China Red Data Book of Endangered Animals – Pisces (Yue and Chen 1998). Identification: Dorsal fin iii-7–8; anal fin iii-5; pectoral fin i-16–19; pelvic fin i-8–10; lateral line scales 95–109, pharyngeal teeth in three rows 2,3, 4–4,3,2 or 2,3,5–5,3,2; mouth terminal; lower jaw without sharp horny edge; lower lip smooth, in two lobes, without median lobe; barbel two pairs, less than half of eye diameter in length; thorax between isthmus and fore-abdomen naked; lateral line complete; last unbranched ray of dorsal fin hard, with posterior serrations (Yue 2000). Distribution: Endemic to Erhai Lake (25°36′–25°58′N, 100°05′–100°17′E, 1,974 m above sea level, 249.34 km), Lancang River, Yunnan Province. Abundance: Accounted for 30% of total harvest in Erhai Lake before the mid20th century (Wu and Wang 1999), but now is rarely found (Huang 1996). Habitat and ecology: Usually inhabits quiet, open areas of lakes, mainly feeding on zooplankton. Migrates upstream or assembles around spring-fed caves during spring for spawning (Yue and Chen 1998). Reproduction: Matures at 3–4 years (Leng et al. 2006). Spawns over sandy and gravel bottom or upwelling groundwater in lakes (Huang 1996). Threats: It lives and spawns mainly in ditches and caves of shallow lakes and creeks entering the lake, many of which have dried up since 1970s from human activity. Introduced exotic fish species are serious egg predators (Yang 1996). Overfishing contributed to the drastic population depletion (Yue and Chen 1998). Conservation action: Cangshan Mountain and Erhai Lake National Nature Reserve was established in 1981 and became national level in 1994. Local government enacted the “Erhai Lake Administrative Regulation” to protect this species (Yue and Chen 1998). Conservation recommendation: Research for population preservation and restoration is required. Fishing regulations need to be enhanced. Exotic fishes should be removed. Natural habitats should be protected. Environ Biol Fish (2009) 86:29–30 DOI 10.1007/s10641-007-9302-x

Threatened fishes of the world: Schizothorax taliensis

Common name: Dali schizothoracin. Conservation status: Endangered in China Red Data Book of Endangered Animals – Pisces (Yue and Chen 1998). Identification: Dorsal fin iii-7–8; anal fin iii-5; pectoral fin i-16–19; pelvic fin i-8–10; lateral line scales 95–109, pharyngeal teeth in three rows 2,3, 4–4,3,2 or 2,3,5–5,3,2; mouth terminal; lower jaw without sharp horny edge; lower lip smooth, in two lobes, without median lobe; barbel two pairs, less than half of eye diameter in length; thorax between isthmus and fore-abdomen naked; lateral line complete; last unbranched ray of dorsal fin hard, with posterior serrations (Yue 2000). Distribution: Endemic to Erhai Lake (25°36′–25°58′N, 100°05′–100°17′E, 1,974 m above sea level, 249.34 km), Lancang River, Yunnan Province. Abundance: Accounted for 30% of total harvest in Erhai Lake before the mid20th century (Wu and Wang 1999), but now is rarely found (Huang 1996). Habitat and ecology: Usually inhabits quiet, open areas of lakes, mainly feeding on zooplankton. Migrates upstream or assembles around spring-fed caves during spring for spawning (Yue and Chen 1998). Reproduction: Matures at 3–4 years (Leng et al. 2006). Spawns over sandy and gravel bottom or upwelling groundwater in lakes (Huang 1996). Threats: It lives and spawns mainly in ditches and caves of shallow lakes and creeks entering the lake, many of which have dried up since 1970s from human activity. Introduced exotic fish species are serious egg predators (Yang 1996). Overfishing contributed to the drastic population depletion (Yue and Chen 1998). Conservation action: Cangshan Mountain and Erhai Lake National Nature Reserve was established in 1981 and became national level in 1994. Local government enacted the “Erhai Lake Administrative Regulation” to protect this species (Yue and Chen 1998). Conservation recommendation: Research for population preservation and restoration is required. Fishing regulations need to be enhanced. Exotic fishes should be removed. Natural habitats should be protected. Environ Biol Fish (2009) 86:29–30 DOI 10.1007/s10641-007-9302-x