Isopod crustaceans of the family Dajidae are exclusively marine ectoparasites.The genus Notophryxus G.O.Sars,1883 currently includes nine nominal species,which are very rarely reported as the chances for encountering ...Isopod crustaceans of the family Dajidae are exclusively marine ectoparasites.The genus Notophryxus G.O.Sars,1883 currently includes nine nominal species,which are very rarely reported as the chances for encountering these specimens are unpredictable.Our comprehension of the taxonomy,biology,ecology,and life cycle of species belonging to the Notophryxus genus is notably lacking.All nominal species of Notophryxus genus are reviewed here to obtain a comprehensive and integrative taxonomic understanding of this genus,in an attempt to address the lacunae.This paper also documents the rediscovery of an ectoparasitic isopod from the genus Notophryxus in Indian waters,after 55 years.Adult isopod specimens obtained from the outer reefs of Amini Island in the Lakshadweep archipelago,Southeastern Arabian Sea,display morphological congruence to Notophryxus globularis G.O.Sars,1885.The only previous report on this species dates back to 1885 from G.O.Sars'description of N.globularis as an ectoparasite on the euphausiid Thysanoessa gregaria G.O.Sars,1883 in the North Pacific.This discovery represents a range extension of N.globularis from the North Pacific to the Arabian Sea.Two cryptoniscid larvae and three adult females of N.globularis(with dwarf males)were found attached to four adult mysid specimens of Siriella aequiremis Hansen,1910.The present study provides an improved diagnosis of N.globularis with the aid of light microscopy images and line drawings which was not given in the original G.O.Sars,1885 report.This research also provides a concise description of cryptoniscid larvae from the same sampling location and same host which is most likely to be N.globularis larvae.展开更多
This paper describes the fishery catch structure of Vembanad wetland system during August 2012 to July 2013. The estimates of fishery production indicated an annual landing of 4387.31 t, in which 480.98 t and 3906.33 ...This paper describes the fishery catch structure of Vembanad wetland system during August 2012 to July 2013. The estimates of fishery production indicated an annual landing of 4387.31 t, in which 480.98 t and 3906.33 t contributed by southern and northern zone of Vembanad respectively. Eighty species of finfishes, five species of penaeid shrimps, three species of palaemonid prawns and two species of crabs were identified from the study period. The catch per unit effort (CPUE) value was maximum for gill net (3.04 kg·h-1) followed by stake net (2.43 kg·h-1), Chinese dip net (2.01 kg·h-1), seines (1.2 kg·h-1), cast net (0.72 kg·h-1) and hook and line (0.34 kg·h-1). Biological integrity and fishery production of estuaries in the country are declining mainly due to various man induced activities. Thaneermukkom barrage, the salinity barrier, constructed across the Vembanad wetland system in 1976, transforming the water body into two distinct ecosystems, a fresh water zone on the south and a brackish water zone on the north, resulting in gross changes in physical, chemical and biological entity of the aquatic ecosystem. In the southern zone of Vembanad the marine fish species were less available with the closure of the barrage period. There are signs of decline of the Vembanad fishery resources, evident in the lesser number of species and decline of fishery production. This will lead to biodiversity loss, fish stock reduction and will ultimately affect the livelihood support of the traditional fishers to a large extent, besides affecting other ecological services. A better conservation measure must be implemented for maintaining the sustainable fishery resources in Vembanad.展开更多
基金the Council of Scientific and Industrial Research (CSIR), New Delhi for the award of Junior Research Fellowship (JRF, 09/239(0555)/2019-EMR-I)
文摘Isopod crustaceans of the family Dajidae are exclusively marine ectoparasites.The genus Notophryxus G.O.Sars,1883 currently includes nine nominal species,which are very rarely reported as the chances for encountering these specimens are unpredictable.Our comprehension of the taxonomy,biology,ecology,and life cycle of species belonging to the Notophryxus genus is notably lacking.All nominal species of Notophryxus genus are reviewed here to obtain a comprehensive and integrative taxonomic understanding of this genus,in an attempt to address the lacunae.This paper also documents the rediscovery of an ectoparasitic isopod from the genus Notophryxus in Indian waters,after 55 years.Adult isopod specimens obtained from the outer reefs of Amini Island in the Lakshadweep archipelago,Southeastern Arabian Sea,display morphological congruence to Notophryxus globularis G.O.Sars,1885.The only previous report on this species dates back to 1885 from G.O.Sars'description of N.globularis as an ectoparasite on the euphausiid Thysanoessa gregaria G.O.Sars,1883 in the North Pacific.This discovery represents a range extension of N.globularis from the North Pacific to the Arabian Sea.Two cryptoniscid larvae and three adult females of N.globularis(with dwarf males)were found attached to four adult mysid specimens of Siriella aequiremis Hansen,1910.The present study provides an improved diagnosis of N.globularis with the aid of light microscopy images and line drawings which was not given in the original G.O.Sars,1885 report.This research also provides a concise description of cryptoniscid larvae from the same sampling location and same host which is most likely to be N.globularis larvae.
文摘This paper describes the fishery catch structure of Vembanad wetland system during August 2012 to July 2013. The estimates of fishery production indicated an annual landing of 4387.31 t, in which 480.98 t and 3906.33 t contributed by southern and northern zone of Vembanad respectively. Eighty species of finfishes, five species of penaeid shrimps, three species of palaemonid prawns and two species of crabs were identified from the study period. The catch per unit effort (CPUE) value was maximum for gill net (3.04 kg·h-1) followed by stake net (2.43 kg·h-1), Chinese dip net (2.01 kg·h-1), seines (1.2 kg·h-1), cast net (0.72 kg·h-1) and hook and line (0.34 kg·h-1). Biological integrity and fishery production of estuaries in the country are declining mainly due to various man induced activities. Thaneermukkom barrage, the salinity barrier, constructed across the Vembanad wetland system in 1976, transforming the water body into two distinct ecosystems, a fresh water zone on the south and a brackish water zone on the north, resulting in gross changes in physical, chemical and biological entity of the aquatic ecosystem. In the southern zone of Vembanad the marine fish species were less available with the closure of the barrage period. There are signs of decline of the Vembanad fishery resources, evident in the lesser number of species and decline of fishery production. This will lead to biodiversity loss, fish stock reduction and will ultimately affect the livelihood support of the traditional fishers to a large extent, besides affecting other ecological services. A better conservation measure must be implemented for maintaining the sustainable fishery resources in Vembanad.
