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Papers by Dr.Rohini Krishna

Research paper thumbnail of Morphological, anatomical and reproductive features of Loliolus (Loliolus) hardwickei (Gray, 1849) caught from the Vizhinjam Coast, Kerala, India

Indian Journal of Fisheries, Mar 31, 2018

The morphological, anatomical and reproductive features of the little Indian squid, Loliolus (Lol... more The morphological, anatomical and reproductive features of the little Indian squid, Loliolus (Loliolus) hardwickei (Gray, 1849) were studied based on samples collected from boat seine operated along the Vizhinjam Coast. The species was found to be a new entrant to the fishery along the Vizhinjam Coast. A total of 27 morphometric characters were measured and 13 indices were calculated and reported. Dorsal mantle length (DML) of the specimens ranged from 2.6 to 6.8 cm with a mean DML of 4.5±0.88 cm. The largest specimen observed was a male with DML 6.8 cm. Fully mature (Stage IV) specimens were found to have a higher gonadosomatic index (12.54±2.64 in females and 0.8±0.21 in males). Average length and width of spermatophores were 3.078±0.092 mm and 0.11±0.02 mm respectively. Samples with higher DML were in advanced maturity stages (Stage V). Size composition (DML) of samples revealed that 50% of squids were within the 4-5 cm size range.

Research paper thumbnail of Seasonal availability and population structure of Eurobowmaniella simulans W. Tattersall, 1915 (Crustacea: Mysida) along Vizhinjam coast, Kerala, India

Journal of the Marine Biological Association of India, May 30, 2016

Eurobowmaniella simulans is the commonly available species of mysid along the Vizhinjam coast of ... more Eurobowmaniella simulans is the commonly available species of mysid along the Vizhinjam coast of Kerala. Sampling of mysids has been carried out over a period of one year from March 2014 to February 2015 to study the seasonal availability and population structure. Monthly samples of mysids consisted of individuals in various developmental stages, from juveniles to mature mysids around the year, but their percentage availability varied. The peak availability of mysids was recorded during September (2014) (avg. 48,731 numbers per haul) and their availability was lowest in July (2014) with an average of 2 individuals per haul. The availability of brooding or ovigerous females were observed throughout the year and highest and lowest percentage availability was during November (2014) and April (2014) respectively. Morphometric measurements of E. simulans revealed that their average size (TL) ranged from 2.35±0.52 mm-(juvenile) to 7.47±1.75 mm (adult). Sex could be first distinguished externally when mysid attains the total length between 4.1 mm and 5 mm. Analysis of variance of different water quality parameters and mysid density comparing seasons revealed that there was significant variation of mysid availability between seasons (P < 0.05). Multivariate Pearson's correlation analysis of water quality parameters and mysid density showed that there was a significant relation with chlorophyll a content (P < 0.001) of seawater. The present study also revealed that mysids are available in harvestable quantities for aquaculture purposes from August to November.

Research paper thumbnail of Recent advances in marine ornamental breeding and seed production at Vizhinjam Regional Centre of CMFRI India

Frontiers in Marine Science, Dec 9, 2022

The marine ornamental fish trading industry is an ever-expanding one, as indicated by its bolster... more The marine ornamental fish trading industry is an ever-expanding one, as indicated by its bolstering statistics, which amount to about US$ 300 million. Although the trade is booming, the natural habitats that foster these fishes, such as coral reefs, are steadily declining. One of the reasons for this is the overdependency of the industry on wild-caught fishes. To surpass this, the Central Marine Fisheries Research Institute (CMFRI) has developed hatchery technology for breeding marine ornamental fishes such as seahorses, clownfishes, damsels, and serranids. It began with the breeding of Hippocampus kuda. This progressed to breeding clownfishes such as Amphiprion chrysogaster, A. ocellaris, A. nigripes, A. peridarion, and A. ephippium and Premnas biaculeatus. Damsel fishes that were bred successfully include Chrysiptera cyanea, C. hemicyanea Neopomacentrus cyanomos, N. nemurus, and Dascyllus carneus. The recirculating aquaculture system (RAS) designed in the Vizhinjam Regional Centre of CMFRI is being used for broodstock development of serranids, tangs, squirrel fishes, and soldier fishes. A standard method was developed for captive breeding and hatchery rearing of anthias Pseudanthias marcia and P. squamipinnis in an advanced indigenous RAS system. The present article provides a bird's eye view of the important research work done in India concerning marine ornamental fish breeding and reviews important breeding work carried out at Vizhinjam Regional Centre of CMFRI.

Research paper thumbnail of Studies on damsel fishes found along the Vizhinjam Coast

Research paper thumbnail of Studies on Egg Morphology, Availability and Hatching of Four Species of Cephalopods along Vizhinjam Coast, Kerala

International journal of innovative research and development, 2015

Availability and characteristics of cephalopod egg mass along the Vizhinjam coast was studied and... more Availability and characteristics of cephalopod egg mass along the Vizhinjam coast was studied and peak availability of egg mass of squids Uroteuthis (Photololigo) duvaucelii, Sepioteuthislessoniana, was noticed during August to October, whereas, the peak availability of egg mass of cuttlefishSepiellainermis, and Sepia pharonis was noticed during December to February. Egg clusters of Uroteuthis (Photololigo) duvaucelii, Sepiellainermis, and Sepia pharoniswereobtained from shore seine catches, whereas the egg mass of Sepioteuthislessoniana was found attached to coconutspadices and nylon ropes hung from rafts moored at Vizhinjam bay. Eggs of Uroteuthis (Photololigo) duvaucelii were encased in gelatinous, whitish, transparent, club shaped capsules. The egg capsule measured4.5 - 6cm in length and 1.5-2cm in width, contained 120-130 eggs. It took total of 8 days for complete hatching. Egg cluster of Sepioteuthislessoniana consisted 50-70 creamy white, slender, finger like capsules. Len...

Research paper thumbnail of Seasonal availability and population structure of Eurobowmaniella simulans W. Tattersall, 1915 (Crustacea: Mysida) along Vizhinjam coast, Kerala, India

Journal of the Marine Biological Association of India, 2016

Eurobowmaniella simulans is the commonly available species of mysid along the Vizhinjam coast of ... more Eurobowmaniella simulans is the commonly available species of mysid along the Vizhinjam coast of Kerala. Sampling of mysids has been carried out over a period of one year from March 2014 to February 2015 to study the seasonal availability and population structure. Monthly samples of mysids consisted of individuals in various developmental stages, from juveniles to mature mysids around the year, but their percentage availability varied. The peak availability of mysids was recorded during September (2014) (avg. 48,731 numbers per haul) and their availability was lowest in July (2014) with an average of 2 individuals per haul. The availability of brooding or ovigerous females were observed throughout the year and highest and lowest percentage availability was during November (2014) and April (2014) respectively. Morphometric measurements of E. simulans revealed that their average size (TL) ranged from 2.35±0.52 mm-(juvenile) to 7.47±1.75 mm (adult). Sex could be first distinguished externally when mysid attains the total length between 4.1 mm and 5 mm. Analysis of variance of different water quality parameters and mysid density comparing seasons revealed that there was significant variation of mysid availability between seasons (P < 0.05). Multivariate Pearson's correlation analysis of water quality parameters and mysid density showed that there was a significant relation with chlorophyll a content (P < 0.001) of seawater. The present study also revealed that mysids are available in harvestable quantities for aquaculture purposes from August to November.

Research paper thumbnail of Egg and Larval Development of Serranid Fish Marcia’s Anthias, Pseudanthias marcia (Subfamily: Anthiinae) Spawned and Reared under Captive Condition

Thalassas: An International Journal of Marine Sciences, 2020

The embryonic and larval development of volitionally spawned eggs of the serranid fish Marcia's a... more The embryonic and larval development of volitionally spawned eggs of the serranid fish Marcia's anthias, Pseudanthias marcia (Randall and Hoover 1993) is described and illustrated based on observations during spawning, hatching and larval rearing trials. Eggs were obtained from volitional spawning of P. marcia under captive conditions in Re-circulating Aquaculture System (RAS) in which the sea water is re-circulated at the rate of 1500 L per hour. Fertilized eggs of P. marcia were pelagic, non adhesive, transparent and measured 617.891 ± 14.9 μ (mean ± SD). Each egg had a single oil globule which measured in 125.866 ± 14.06 μ (mean ± SD).Cell division or two cell stage started forming after 14 min of collection of the fertilized eggs from the brood stock tank. Larval motility began after 14:30 h and hatching occurred after 14:50 h at 29°C. Average total length of the newly hatched larvae was 1206.55 ± 100.02 μ and the yolk sac length was 826.00 ± 46.00 μ. On 3rd dph (days post hatch), the total length of the larvae was 1906.26 ± 32.3 μ. Pigmentations patterns were observed in freshly hatched larvae after 4 h of hatching, with the presence of eight pigmented areas on the dorsal surface of the larva and one spot on the posterior tip of the yolk sac. Notochord flexion stage was complete on 25 dph (TL-4.85 mm). Between 32 and 34 dph larvae metamorphosed to adult shape. Adult coloration and forked caudal fin shape was observed after 50 days of post hatch and the total body length of the larvae was 42-43 mm.

Research paper thumbnail of Morphological, anatomical and reproductive features of Loliolus (Loliolus) hardwickei (Gray, 1849) caught from the Vizhinjam Coast, Kerala, India

Indian Journal of Fisheries, Mar 31, 2018

The morphological, anatomical and reproductive features of the little Indian squid, Loliolus (Lol... more The morphological, anatomical and reproductive features of the little Indian squid, Loliolus (Loliolus) hardwickei (Gray, 1849) were studied based on samples collected from boat seine operated along the Vizhinjam Coast. The species was found to be a new entrant to the fishery along the Vizhinjam Coast. A total of 27 morphometric characters were measured and 13 indices were calculated and reported. Dorsal mantle length (DML) of the specimens ranged from 2.6 to 6.8 cm with a mean DML of 4.5±0.88 cm. The largest specimen observed was a male with DML 6.8 cm. Fully mature (Stage IV) specimens were found to have a higher gonadosomatic index (12.54±2.64 in females and 0.8±0.21 in males). Average length and width of spermatophores were 3.078±0.092 mm and 0.11±0.02 mm respectively. Samples with higher DML were in advanced maturity stages (Stage V). Size composition (DML) of samples revealed that 50% of squids were within the 4-5 cm size range.

Research paper thumbnail of Seasonal availability and population structure of Eurobowmaniella simulans W. Tattersall, 1915 (Crustacea: Mysida) along Vizhinjam coast, Kerala, India

Journal of the Marine Biological Association of India, May 30, 2016

Eurobowmaniella simulans is the commonly available species of mysid along the Vizhinjam coast of ... more Eurobowmaniella simulans is the commonly available species of mysid along the Vizhinjam coast of Kerala. Sampling of mysids has been carried out over a period of one year from March 2014 to February 2015 to study the seasonal availability and population structure. Monthly samples of mysids consisted of individuals in various developmental stages, from juveniles to mature mysids around the year, but their percentage availability varied. The peak availability of mysids was recorded during September (2014) (avg. 48,731 numbers per haul) and their availability was lowest in July (2014) with an average of 2 individuals per haul. The availability of brooding or ovigerous females were observed throughout the year and highest and lowest percentage availability was during November (2014) and April (2014) respectively. Morphometric measurements of E. simulans revealed that their average size (TL) ranged from 2.35±0.52 mm-(juvenile) to 7.47±1.75 mm (adult). Sex could be first distinguished externally when mysid attains the total length between 4.1 mm and 5 mm. Analysis of variance of different water quality parameters and mysid density comparing seasons revealed that there was significant variation of mysid availability between seasons (P < 0.05). Multivariate Pearson's correlation analysis of water quality parameters and mysid density showed that there was a significant relation with chlorophyll a content (P < 0.001) of seawater. The present study also revealed that mysids are available in harvestable quantities for aquaculture purposes from August to November.

Research paper thumbnail of Recent advances in marine ornamental breeding and seed production at Vizhinjam Regional Centre of CMFRI India

Frontiers in Marine Science, Dec 9, 2022

The marine ornamental fish trading industry is an ever-expanding one, as indicated by its bolster... more The marine ornamental fish trading industry is an ever-expanding one, as indicated by its bolstering statistics, which amount to about US$ 300 million. Although the trade is booming, the natural habitats that foster these fishes, such as coral reefs, are steadily declining. One of the reasons for this is the overdependency of the industry on wild-caught fishes. To surpass this, the Central Marine Fisheries Research Institute (CMFRI) has developed hatchery technology for breeding marine ornamental fishes such as seahorses, clownfishes, damsels, and serranids. It began with the breeding of Hippocampus kuda. This progressed to breeding clownfishes such as Amphiprion chrysogaster, A. ocellaris, A. nigripes, A. peridarion, and A. ephippium and Premnas biaculeatus. Damsel fishes that were bred successfully include Chrysiptera cyanea, C. hemicyanea Neopomacentrus cyanomos, N. nemurus, and Dascyllus carneus. The recirculating aquaculture system (RAS) designed in the Vizhinjam Regional Centre of CMFRI is being used for broodstock development of serranids, tangs, squirrel fishes, and soldier fishes. A standard method was developed for captive breeding and hatchery rearing of anthias Pseudanthias marcia and P. squamipinnis in an advanced indigenous RAS system. The present article provides a bird's eye view of the important research work done in India concerning marine ornamental fish breeding and reviews important breeding work carried out at Vizhinjam Regional Centre of CMFRI.

Research paper thumbnail of Studies on damsel fishes found along the Vizhinjam Coast

Research paper thumbnail of Studies on Egg Morphology, Availability and Hatching of Four Species of Cephalopods along Vizhinjam Coast, Kerala

International journal of innovative research and development, 2015

Availability and characteristics of cephalopod egg mass along the Vizhinjam coast was studied and... more Availability and characteristics of cephalopod egg mass along the Vizhinjam coast was studied and peak availability of egg mass of squids Uroteuthis (Photololigo) duvaucelii, Sepioteuthislessoniana, was noticed during August to October, whereas, the peak availability of egg mass of cuttlefishSepiellainermis, and Sepia pharonis was noticed during December to February. Egg clusters of Uroteuthis (Photololigo) duvaucelii, Sepiellainermis, and Sepia pharoniswereobtained from shore seine catches, whereas the egg mass of Sepioteuthislessoniana was found attached to coconutspadices and nylon ropes hung from rafts moored at Vizhinjam bay. Eggs of Uroteuthis (Photololigo) duvaucelii were encased in gelatinous, whitish, transparent, club shaped capsules. The egg capsule measured4.5 - 6cm in length and 1.5-2cm in width, contained 120-130 eggs. It took total of 8 days for complete hatching. Egg cluster of Sepioteuthislessoniana consisted 50-70 creamy white, slender, finger like capsules. Len...

Research paper thumbnail of Seasonal availability and population structure of Eurobowmaniella simulans W. Tattersall, 1915 (Crustacea: Mysida) along Vizhinjam coast, Kerala, India

Journal of the Marine Biological Association of India, 2016

Eurobowmaniella simulans is the commonly available species of mysid along the Vizhinjam coast of ... more Eurobowmaniella simulans is the commonly available species of mysid along the Vizhinjam coast of Kerala. Sampling of mysids has been carried out over a period of one year from March 2014 to February 2015 to study the seasonal availability and population structure. Monthly samples of mysids consisted of individuals in various developmental stages, from juveniles to mature mysids around the year, but their percentage availability varied. The peak availability of mysids was recorded during September (2014) (avg. 48,731 numbers per haul) and their availability was lowest in July (2014) with an average of 2 individuals per haul. The availability of brooding or ovigerous females were observed throughout the year and highest and lowest percentage availability was during November (2014) and April (2014) respectively. Morphometric measurements of E. simulans revealed that their average size (TL) ranged from 2.35±0.52 mm-(juvenile) to 7.47±1.75 mm (adult). Sex could be first distinguished externally when mysid attains the total length between 4.1 mm and 5 mm. Analysis of variance of different water quality parameters and mysid density comparing seasons revealed that there was significant variation of mysid availability between seasons (P < 0.05). Multivariate Pearson's correlation analysis of water quality parameters and mysid density showed that there was a significant relation with chlorophyll a content (P < 0.001) of seawater. The present study also revealed that mysids are available in harvestable quantities for aquaculture purposes from August to November.

Research paper thumbnail of Egg and Larval Development of Serranid Fish Marcia’s Anthias, Pseudanthias marcia (Subfamily: Anthiinae) Spawned and Reared under Captive Condition

Thalassas: An International Journal of Marine Sciences, 2020

The embryonic and larval development of volitionally spawned eggs of the serranid fish Marcia's a... more The embryonic and larval development of volitionally spawned eggs of the serranid fish Marcia's anthias, Pseudanthias marcia (Randall and Hoover 1993) is described and illustrated based on observations during spawning, hatching and larval rearing trials. Eggs were obtained from volitional spawning of P. marcia under captive conditions in Re-circulating Aquaculture System (RAS) in which the sea water is re-circulated at the rate of 1500 L per hour. Fertilized eggs of P. marcia were pelagic, non adhesive, transparent and measured 617.891 ± 14.9 μ (mean ± SD). Each egg had a single oil globule which measured in 125.866 ± 14.06 μ (mean ± SD).Cell division or two cell stage started forming after 14 min of collection of the fertilized eggs from the brood stock tank. Larval motility began after 14:30 h and hatching occurred after 14:50 h at 29°C. Average total length of the newly hatched larvae was 1206.55 ± 100.02 μ and the yolk sac length was 826.00 ± 46.00 μ. On 3rd dph (days post hatch), the total length of the larvae was 1906.26 ± 32.3 μ. Pigmentations patterns were observed in freshly hatched larvae after 4 h of hatching, with the presence of eight pigmented areas on the dorsal surface of the larva and one spot on the posterior tip of the yolk sac. Notochord flexion stage was complete on 25 dph (TL-4.85 mm). Between 32 and 34 dph larvae metamorphosed to adult shape. Adult coloration and forked caudal fin shape was observed after 50 days of post hatch and the total body length of the larvae was 42-43 mm.