In this study we aimed to analyze the effects of water temperature and diet on the length-weight rela- tionship and condition of juvenile Malabar blood snapper Lutjanus malabaricus over a 30-d experimental period. The...In this study we aimed to analyze the effects of water temperature and diet on the length-weight rela- tionship and condition of juvenile Malabar blood snapper Lutjanus malabaricus over a 30-d experimental period. The experiment was conducted in the laboratory using a flow-through-sea-water system. The fish were subjected to four different temperatures （22, 26, 30, and 34 ℃） and two diets （commercial pellet and natural shrimp）. Fish were fed twice daily. L. malabancus exhibited negative allometric growth （b〈3） at the beginning of the experiment （Day 0） at all temperatures and both diets except for 22 ℃ fed with shrimp, which showed isometric growth （b=3）. Conversely, at the end of the experiment （Day 30） fish showed isometric growth （b=3） at 30 ℃ fed with the pellet diet, indicating that the shape of the fish did not change with increasing weight and length, and a positive allometric growth （b〉3） at 30 ℃ fed with shrimp diet, which indicated that fish weight increases faster than their length. The rest of the temperatures represented negative allometric growth （b〈3） on both diet, meaning that fish became lighter with increasing size. The condition factors in the initial and final measurements were greater than 1, indicating the state of health of the fish, except for those fed on a pellet diet at 34 ℃. However, the best condition was obtained at 30 ℃ on both diets. Nev- ertheless, diets did not have a significant effect on growth and condition of juvenile L. malabaricus. The data obtained from this study suggested culturing L. malabaricus at 30 ℃ and feeding on the pellet or shrimp diet, which will optimize the overall production and condition of this commercially important fish species.展开更多
The aim of this study is to report the length-weight relationship parameters （a and b） for some economically important fish species from Iranian freshwaters. The length-weight relationships （LWR） are calculated fo...The aim of this study is to report the length-weight relationship parameters （a and b） for some economically important fish species from Iranian freshwaters. The length-weight relationships （LWR） are calculated for six freshwater fish species collected during 2006 and 2007 in Iran. The values of the exponent b in the LWR （W=aL^b） vary between 2.985 and 3.543. The LWR with high correlation coefficient （r^2） is significant for all the species. These parameters axe of great importance to evaluate the relative condition of populations, biology, species management and their fisheries and stock assessment. The application of the length-weight relationships presented here should be limited to the observed length ranges.展开更多
The present paper provided length-weight relationship(LWR)and length-length(LLR)relationship for the nine freshwater species from Huaihongxinhe River,a tributary of Huaihe River in east China.The data was based on mon...The present paper provided length-weight relationship(LWR)and length-length(LLR)relationship for the nine freshwater species from Huaihongxinhe River,a tributary of Huaihe River in east China.The data was based on monthly sampling(from August 2016 to December 2016)of the nine fish species.Samples were obtained using barrier net,gill net and ground cage in Huaihongxinhe River.The log-transformed data were used to establish the standard length-body weight and standard length-total length relationships by linear regression analyses.This study would be useful for fishery management and conversation in Huaihe River Basin.展开更多
This study used specimens of marine organisms caught by rectangular midwater trawl in the Cosmonaut Sea,Southern Ocean,in austral summer 2019/2020,to determine species composition and spatial distributions of mesopela...This study used specimens of marine organisms caught by rectangular midwater trawl in the Cosmonaut Sea,Southern Ocean,in austral summer 2019/2020,to determine species composition and spatial distributions of mesopelagic fauna in this sea.The data were also used to calculate the length-weight relationships of three common fishes captured during the survey(Electrona antarctica,Bathylagus antarcticus,and Cyclothone microdon).A total of 385 individual organisms with a total weight of 15462.2 g and representing 17 species were collected across the 11 stations visited.The small-sized crown jellyfish Atolla wyvillei(order Coronatae)was the most-dominant species by number(96 individuals),and the zooplankton Cyllopus lucasii(Amphipoda)also showed high abundance(54 individuals).Among fishes,81 individuals of Notolepis coatsorum(Paralepididae)were caught,followed by 71 individuals of E.antarctica(Myctophidae),25 individuals of B.antarcticus(Bathylagidae),and 16 individuals of C.microdon(Gonostomatidae).Clustering analysis divided the mesopelagic community into“west”and“east”groups,and a greater number of individuals were collected in the western part of the sea.The length-weight relationships of the three common fishes revealed positive allometric growth for B.antarcticus(b=3.16),and negative allometric growth for E.antarctica and C.microdon(both b=2.53).Our descriptions of the mesopelagic-zone community structure and biological features of three common fishes provide basic information on the ecology of the Cosmonaut Sea,Southern Ocean,and will be useful for ecosystem-based fisheries management in this region.展开更多
Length-weight relationship(LWR),condition factor(k)of the black chin tilapia,Sarotherodon melanotheron(Rüppel,1852)from Forcados River estuary Nigeria was investigated.The fish were collected monthly from fisherm...Length-weight relationship(LWR),condition factor(k)of the black chin tilapia,Sarotherodon melanotheron(Rüppel,1852)from Forcados River estuary Nigeria was investigated.The fish were collected monthly from fishermen for a period of 24 months(between April 2012 and March 2014).699 specimens of the fish species were collected.The Length-weight relationship(LWR)of the fish was evaluated using the equation:W=a L^(b) while the condition factor of the fish was determined using the equation;K=100W L^(b).The standard length of sampled S.melanotheron ranged from 4.15 to 18.92 cm,total length 6.01 and 22.5 cm while the weight ranged from 7.85-286.71 g.The b value 2.1299 was less than 3 indicating that the growth pattern of the fish was allometric.The correlation co-efficient(r)value for S.melanotheron was 0.7528.The condition factor for the combined sexes fluctuated monthly.The length-weight relationships and condition factor of S.melanotheron in Forcados river estuary indicated that the fish were above average condition.展开更多
For the conservation of endemic species,it is essential to obtain basic biological data.In this framework,the growth parameters of the fish Coptodon walteri from the Cavally River,an area under the effect of the Ity g...For the conservation of endemic species,it is essential to obtain basic biological data.In this framework,the growth parameters of the fish Coptodon walteri from the Cavally River,an area under the effect of the Ity gold mine in the southwestern part of Cote d’Ivoire,were analyzed.A total of 128 specimens were sampled between May and July 2021,including 72 from the Cavally SMI Hill South sector(CSH),located in the Ity mining area and 56 from the Bakatouo Camp sector(BC),outside the Ity mining area.Specimens were sampled using the standardized fishing method with monofilament gill nets(10,12,15,20 and 30 mm)mesh size.The equations p=aLS^(b)and K=100P/LS^(b)were used to determine the length-weight relationship and the condition coefficient.The allometric coefficient b of the length-weight relationship varied from 3.01 in the Cavally Colline Sud sector to 3.2 in the Bakatouo sector.Specimens from the Cavally Colline Sud sector exhibited isometric growth,while those from the Bakatouo sector displayed positive allometric growth.The average condition factor varied from 1.46±0.24 for the Bakatouo sector and 2.06±0.28 for the Cavally Colline Sud sector.The results obtained provide information on the living conditions of Coptodon walteri sampled at the two sites of the Cavally River.These results show the consequences of gold panning on the growth parameters of C.walteri living in this part of the river.展开更多
Classical sorting by reversals uses the unit-cost model, that is, each reversal consumes an equal cost. This model limits the biological meaning of sorting by reversal. Bender and his colleagues extended it by assigni...Classical sorting by reversals uses the unit-cost model, that is, each reversal consumes an equal cost. This model limits the biological meaning of sorting by reversal. Bender and his colleagues extended it by assigning a cost function f（1） = l^a for all a≥ 0, where l is the length of the reversed subsequence. In this paper, we extend their results by considering a model in which long reversals are prohibited. Using the same cost function above for permitted reversals, we present tight or nearly tight bounds for the worst-case cost of sorting by reversals. Then we develop algorithms to approximate the optimal cost to sort a given 0/1 sequence as well as a given permutation. Our proposed problems are more biologically meaningful and more algorithmically general and challenging than the problem considered by Bender et al. Furthermore, our bounds are tight and nearly tight, whereas our algorithms provide good approximation ratios compared to the optimal cost to sort 0/1 sequences or permutations by reversals.展开更多
基金supported by the Ministry of Science Technology and Innovation Malaysia(MOSTI)(No.04-01-02-SF1208)
文摘In this study we aimed to analyze the effects of water temperature and diet on the length-weight rela- tionship and condition of juvenile Malabar blood snapper Lutjanus malabaricus over a 30-d experimental period. The experiment was conducted in the laboratory using a flow-through-sea-water system. The fish were subjected to four different temperatures （22, 26, 30, and 34 ℃） and two diets （commercial pellet and natural shrimp）. Fish were fed twice daily. L. malabancus exhibited negative allometric growth （b〈3） at the beginning of the experiment （Day 0） at all temperatures and both diets except for 22 ℃ fed with shrimp, which showed isometric growth （b=3）. Conversely, at the end of the experiment （Day 30） fish showed isometric growth （b=3） at 30 ℃ fed with the pellet diet, indicating that the shape of the fish did not change with increasing weight and length, and a positive allometric growth （b〉3） at 30 ℃ fed with shrimp diet, which indicated that fish weight increases faster than their length. The rest of the temperatures represented negative allometric growth （b〈3） on both diet, meaning that fish became lighter with increasing size. The condition factors in the initial and final measurements were greater than 1, indicating the state of health of the fish, except for those fed on a pellet diet at 34 ℃. However, the best condition was obtained at 30 ℃ on both diets. Nev- ertheless, diets did not have a significant effect on growth and condition of juvenile L. malabaricus. The data obtained from this study suggested culturing L. malabaricus at 30 ℃ and feeding on the pellet or shrimp diet, which will optimize the overall production and condition of this commercially important fish species.
文摘The aim of this study is to report the length-weight relationship parameters （a and b） for some economically important fish species from Iranian freshwaters. The length-weight relationships （LWR） are calculated for six freshwater fish species collected during 2006 and 2007 in Iran. The values of the exponent b in the LWR （W=aL^b） vary between 2.985 and 3.543. The LWR with high correlation coefficient （r^2） is significant for all the species. These parameters axe of great importance to evaluate the relative condition of populations, biology, species management and their fisheries and stock assessment. The application of the length-weight relationships presented here should be limited to the observed length ranges.
基金Supported by Key R&D Program of Anhui Province(1804a07020144)Program of Introducing and Stabling Talents in Anhui Agricultural University(yj2017-25)。
文摘The present paper provided length-weight relationship(LWR)and length-length(LLR)relationship for the nine freshwater species from Huaihongxinhe River,a tributary of Huaihe River in east China.The data was based on monthly sampling(from August 2016 to December 2016)of the nine fish species.Samples were obtained using barrier net,gill net and ground cage in Huaihongxinhe River.The log-transformed data were used to establish the standard length-body weight and standard length-total length relationships by linear regression analyses.This study would be useful for fishery management and conversation in Huaihe River Basin.
基金financially supported by National Polar Special Program“Impact and Response of Antarctic Seas to Climate Change”(Grant no.IRASCC 01-02-05C).
文摘This study used specimens of marine organisms caught by rectangular midwater trawl in the Cosmonaut Sea,Southern Ocean,in austral summer 2019/2020,to determine species composition and spatial distributions of mesopelagic fauna in this sea.The data were also used to calculate the length-weight relationships of three common fishes captured during the survey(Electrona antarctica,Bathylagus antarcticus,and Cyclothone microdon).A total of 385 individual organisms with a total weight of 15462.2 g and representing 17 species were collected across the 11 stations visited.The small-sized crown jellyfish Atolla wyvillei(order Coronatae)was the most-dominant species by number(96 individuals),and the zooplankton Cyllopus lucasii(Amphipoda)also showed high abundance(54 individuals).Among fishes,81 individuals of Notolepis coatsorum(Paralepididae)were caught,followed by 71 individuals of E.antarctica(Myctophidae),25 individuals of B.antarcticus(Bathylagidae),and 16 individuals of C.microdon(Gonostomatidae).Clustering analysis divided the mesopelagic community into“west”and“east”groups,and a greater number of individuals were collected in the western part of the sea.The length-weight relationships of the three common fishes revealed positive allometric growth for B.antarcticus(b=3.16),and negative allometric growth for E.antarctica and C.microdon(both b=2.53).Our descriptions of the mesopelagic-zone community structure and biological features of three common fishes provide basic information on the ecology of the Cosmonaut Sea,Southern Ocean,and will be useful for ecosystem-based fisheries management in this region.
文摘Length-weight relationship(LWR),condition factor(k)of the black chin tilapia,Sarotherodon melanotheron(Rüppel,1852)from Forcados River estuary Nigeria was investigated.The fish were collected monthly from fishermen for a period of 24 months(between April 2012 and March 2014).699 specimens of the fish species were collected.The Length-weight relationship(LWR)of the fish was evaluated using the equation:W=a L^(b) while the condition factor of the fish was determined using the equation;K=100W L^(b).The standard length of sampled S.melanotheron ranged from 4.15 to 18.92 cm,total length 6.01 and 22.5 cm while the weight ranged from 7.85-286.71 g.The b value 2.1299 was less than 3 indicating that the growth pattern of the fish was allometric.The correlation co-efficient(r)value for S.melanotheron was 0.7528.The condition factor for the combined sexes fluctuated monthly.The length-weight relationships and condition factor of S.melanotheron in Forcados river estuary indicated that the fish were above average condition.
文摘For the conservation of endemic species,it is essential to obtain basic biological data.In this framework,the growth parameters of the fish Coptodon walteri from the Cavally River,an area under the effect of the Ity gold mine in the southwestern part of Cote d’Ivoire,were analyzed.A total of 128 specimens were sampled between May and July 2021,including 72 from the Cavally SMI Hill South sector(CSH),located in the Ity mining area and 56 from the Bakatouo Camp sector(BC),outside the Ity mining area.Specimens were sampled using the standardized fishing method with monofilament gill nets(10,12,15,20 and 30 mm)mesh size.The equations p=aLS^(b)and K=100P/LS^(b)were used to determine the length-weight relationship and the condition coefficient.The allometric coefficient b of the length-weight relationship varied from 3.01 in the Cavally Colline Sud sector to 3.2 in the Bakatouo sector.Specimens from the Cavally Colline Sud sector exhibited isometric growth,while those from the Bakatouo sector displayed positive allometric growth.The average condition factor varied from 1.46±0.24 for the Bakatouo sector and 2.06±0.28 for the Cavally Colline Sud sector.The results obtained provide information on the living conditions of Coptodon walteri sampled at the two sites of the Cavally River.These results show the consequences of gold panning on the growth parameters of C.walteri living in this part of the river.
文摘Classical sorting by reversals uses the unit-cost model, that is, each reversal consumes an equal cost. This model limits the biological meaning of sorting by reversal. Bender and his colleagues extended it by assigning a cost function f（1） = l^a for all a≥ 0, where l is the length of the reversed subsequence. In this paper, we extend their results by considering a model in which long reversals are prohibited. Using the same cost function above for permitted reversals, we present tight or nearly tight bounds for the worst-case cost of sorting by reversals. Then we develop algorithms to approximate the optimal cost to sort a given 0/1 sequence as well as a given permutation. Our proposed problems are more biologically meaningful and more algorithmically general and challenging than the problem considered by Bender et al. Furthermore, our bounds are tight and nearly tight, whereas our algorithms provide good approximation ratios compared to the optimal cost to sort 0/1 sequences or permutations by reversals.
