Seasonal abundance and diversity of finfish in a tropical estuary, Karwar, southwest coast of India

The spatial and seasonal variability in finfish availability in the tropical Kali Estuary, in Karwar was studied from January 2017- May 2019 at three stations. A total of 26 species belonging to 9 orders and 20 families were recorded from the Kali Estuary and the order Perciformes with 16 species dominated the group (62%) followed by order Mugilliformes and Pleuronectiformes (8%). Maximum abundance was observed during the pre-monsoon season in all the stations. Excluding Ambassis ambassis which was abundant in all the stations, Caranx ignobilis dominated in all the stations. Truly marine and estuarine species of fishes recorded dominated than the freshwater estuarine ones like Etroplus suratensis, Scatophagus argus, Aplocheilus lineatus. Number of species recorded at each station during the study ranged from 11 to 25 and it was significantly different between stations. The Shannon- Wiener diversity index ranged from 2.0 to 4.6, the minimum in station 1 and maximum in station 3. The seasonal analysis of diversity also showed minimum value during the monsoon season in station 1 and maximum value in station 3. The minimum value (2.2) of Margalef richness index was also recorded in Station 1 during monsoon season and maximum value (4.2) in Station 2. When comparing the relative abundance using Pielou’s evenness index (J’) the values were in the range of 0.92 to 0.99 which was closer to one, indicating evenness in distribution. There was similarity in species composition according to different seasons except for monsoon season in Station 1. The same pattern was also evident in the MDS plot where seasonal aggregation was observed between the stations. In addition to the diversity studies, the surveys also threw light on the abundance and seasonality of candidate species suitable for mariculture like C. ignobilis, Lutjanus spp., Etroplus spp., etc. Judicious exploitation of the species could help brackishwater fish farmers

Abundance of natural fish seed resources prioritized for mariculture in the Kali estuary

Mariculture is a promising fish producing industry in India with cage farming of marine finfish and shellfish becoming popular along the entire coast. Fish seed availability is the need of the hour for sustaining and supporting expansion of cage farming of fishes in India. Capture Based Aquaculture (CBA), can be considered as an economic activity for fishermen communities to practise where by accessing natural fish seed resources for culture, it enhances the fish production, yield and market value

Brief note on infestation of Diplectanum sp. in Asian seabass

Recently open sea cage farming has emerged as an alternative and additional income source for fishermen and fish farmers in India. Asian seabass, Lates calcarifer is widely used in open sea cage culture due to its high market demand. In cage farming, high stocking densities and poor water quality enhance the parasite loads of the cultured fishes. In this study, 47 specimens of Asian seabass collected from cages located in Naganathwada, Sunkeri, Ankola were analysed with the aim of identifying the parasites prevalent among this species. All external and internal organs of each fish were examined separately under microscope for parasites. The collected monogenean parasites were washed in a 0.85% saline solution and fixed in 70% ethanol and identified. Most of the infected fishes had dark coloration of the body and postmortem findings revealed gills with excessive mucus secretion and sticking of the gill tips with greyish coloration

Report on Amyloodinium spp. cysts infection in clownfish

A study was undertaken to record the occurrence of parasitic infections in ocellaris clownfish, Amphiprion ocellaris. Of a total eight A. ocellaris maintained in hatchery, three were found infected with different developmental stages of Amyloodinium spp. and were kept under observation

Histopathological changes in the gills associated with Dactylogyrus spp. infestation in Orange-spotted Grouper, Epinephelus coioides reared in Sea Cages.

A study was conducted to investigate the histological changes in the gills of orange-spotted grouper infested with flukes of Dactylogyrus spp. Several histological changes were observed in the gill which included complete fusion of secondary lamellae, dilatation of the venous sinus at the middle of the primary lamellae, oedema and complete loss of secondary lamellae, et