NISCAIR Online Periodicals Repository Collection: IJMS Vol.40(6) [December 2011]

Experimental culture of the Pharaoh’s cuttlefish Sepia pharaonis, Ehrenberg 1831, under closed circulation systems

Title: Experimental culture of the Pharaoh’s cuttlefish Sepia pharaonis, Ehrenberg 1831, under closed circulation systems

Authors: Deepak, Samuel.V; Patterson, Jamila

Abstract: Though majority of research findings suggest recirculation systems (RS), the present work was experimented with a closed circulation system (CCS). Successful growth rates were evident up to 130 days where the average dorsal mantle length (DML) was 84 mm and weight 61.43 gms. Effect of salinity on the pralarva at various levels displayed 100% survival rate in the range of 30-34 ppt. Though brine shrimp (Artemia parthenogenetica) was the preferred prey for the first 10 days of culture, Paralarva fed with mysids had better growth rates from 10^th day onwards. Higher survival rate was noted (78%) for Paralarva fed with mysids. The juveniles were trained to accept frozen mysids after 21 days while flesh of fish (Johnius dussumieri) was introduced from 40^th day onwards. In par with the cultures from recirculating systems, closed systems are effective for culture of the Pharaoh’s cuttlefish. Though growth rates tend to be on a negligible lower level, it is evident that these cephalopods can be raised without much of an investment under the CCS.

Page(s): 841-846

Juvenile abundance and post-larval incursion of mud crabs (Scylla spp.) in Chilika lagoon

Title: Juvenile abundance and post-larval incursion of mud crabs (Scylla spp.) in Chilika lagoon

Authors: Mohaptra, Anil; Mohanty, S. K.; Mohanty, Rajeeb K.

Abstract: was carried out on the juvenile abundance and post-larval incursion of two species of Scylla into the lagoon for period of two years from August, 2005-July, 2007. Occurrence of juvenile, S. serrata were throughout the year, while in S. tranquebarica, juveniles were not encountered during December-February. December-May register higher median CPUE values with peak in March for S. serrata. In S. tranquebarica, the peak juvenile abundance period was restricted to June-September with peak in July. The CPUE values for juveniles indicted that the recruitment was intense for S. serrata during post-winter (January-April) and for S. tranquebarica during monsoon (June-September). The crab seeds were available throughout the year which gave a clear evidence for the year round recruitment with the peak during the months of November-March for Scylla species from the Bay of Bengal to the Chilika lagoon. During the study period, the megalopa and first crab instar recruitment per net-hour collection was significantly higher during spring tides than neap tide phase (p< 0.05) and also higher incursion was observed in the night hours than day hours (p< 0.05). Significantly higher night collections of mud crab juveniles (mixed population of both species) from net box traps (khandas) were obtained during new moon phases (t=3.88; d.f.=11; P< 0.01).

Page(s): 834-840

Seasonal variation in the hydrolytic exo-enzyme profile of Vibrio sp. associated with the marine benthic environment of South India

Title: Seasonal variation in the hydrolytic exo-enzyme profile of Vibrio sp. associated with the marine benthic environment of South India

Authors: Raghul, Subin S; Bhat, Sarita G

Abstract: Benthic sediment samples, from both east and west coast of peninsular India were evaluated for the different species of vibrios and their exoenzyme profile. About 800 isolates of Vibrio sp. were isolated and screened for hydrolytic exoenzymes. More than 91% of isolates showed multiple extracellular enzyme profile, synthesizing more than two hydrolytic enzymes. Hydrolytic exoenzyme production was more active during monsoon season. Among the species of vibrios, V. furnissi (30%) was dominant, followed by V. harveyi (23.75%), V. neries (15%) and V. parahaemolyticus (11.25%). Vibrios from the benthic environment were a markedly diverse group playing an important role in mineralization process in the benthic environments.

Page(s): 826-833

Occurrence of red tide caused by Karenia mikimotoi (toxic dinoflagellate) in the Southwest coast of India

Title: Occurrence of red tide caused by Karenia mikimotoi (toxic dinoflagellate) in the Southwest coast of India

Authors: Madhu, N V; Reny, P D; Paul, Meenu; Ullas, N; Resmi, P

Abstract: Intense brownish discoloration was observed in the surface waters of Cochin barmouth on 21^st October 2009, which found to extend a few kilometers in the coastal waters. Continuous monitoring was carried out in the region for a period of 5 days (21^st to 25^th October 2009) and generated data on changes in water quality and phytoplankton community associated with the bloom. Relatively high level of inorganic nutrients (ammonia 0.5-9.7 µM, nitrate 1.3-2.9 µM, phosphate 1-2.3 µM, silicate 23.5-39.9 µM) and chlorophyll a (av. 56.8 ± 23.7 mg m^-3) concentration were observed during the bloom period. Microscopic analysis revealed that the discoloration was caused by an unarmored toxic dinoflagellate, Karenia mikimotoi Miyake & Kominami ex Oda (Karenia, Gymnodiniaceae) belongs to Gymnodiniales, which cause massive fish mortality by releasing hemolytic compounds.

Page(s): 821-825