Age, growth, and reproduction of permit (Trachinotus falcatus) in Florida waters

We examined 536 permit (Trachinotus falcatus, 65–916 mm FL) collected from the waters of Florida Keys and from the Tampa Bay area on Florida’s Gulf coast to describe their growth and reproduction.Among permit that we sexed, females ranged from 266 to 916 mm in length (mean=617) and males ranged from 274 to 855 mm (mean=601). Ages of 297 permit ranging from 102 to 900 mm FL were estimated from thin-sectioned otoliths (sagittae). The large proportion of otoliths with an annulus on the margin and an otolith from an OTC-injected fish suggested that a single annulus was formed each year during late spring or early summer.Permit reach a maximum age of at least 23 years.Permit grew rapidly until an age of about five years, and then growth slowed considerably. Male and female von Bertalanffy growth models were not significantly different, and the sexes-combined growth model was FL=753.1(1–e –0.348(Age+0.585)). Gonad development was seasonal, and spawning occurred during late spring and summer over artificial and natural reefs at depths of 10–30 m. Ovaries that contained oocytes in the final stages of oocyte maturation or postovulatory follicles were found during May–July. We estimated that 50% of the females in the population had reached sexual maturity by 547 mm and an age of 3.1 years and that 50% of the males in the population had reached sexual maturity by 486 mm and an age of 2.3 years. Because Florida regulations restrict the maximum size of permit caught in recreational and commercial fisheries to 20-inch (508-mm), most fish harvested are sexually immature. With the current size selectivity of the fishery, the spawning stock biomass of permit could decrease quickly in response to moderate levels of fishing mortality; thus, the regulations in place in Florida to restrict harvest levels appear to be justified.

Maturity and spawning of Otolithus argenteus (Cuvier) from Karwar waters

The present paper deals in the maturity stages, ova diameter and spawning season, of Otolithus argenteus from Karwar waters. The seven stages of maturity were determined based on the macroscopic appearance and microscopic study of intra ovarian eggs. The average size at first maturity was found to be 160 mm. The diameter of ova varies from 0.01 to 0.82 mm. with various modes, indicating the nature and the frequency of spawning.

Developmental characters of Psettina Iijimae (Jordan and Starks), bothid flat fishes - Pisces

Post larval stages of Psettina Iijimae ranging from 1.8 mm NL to 44.6 mm SL collected during Naga Expedition and International Indian Ocean Expedition (IIOE) are described. The characteristics which help to identify larval stages of Psettina are: the presence of pigmented urohyal appendage in early stages which is progressively reduced during flexion stages and which disappears in later postflexion stages, the meristics, the spines on urohyal and posterior basipterygial processes and the absence of spines on cleithra. The P. iijimae can be distinguished by the presence of spines on the median fin rays which differentiate near the baseosts along the dorsal and ventral body wall much before the fin rays. The larvae of P.iijimae were more abundant in the Gulf of Thailand compared to South China Sea and Indian Ocean.

Monoculture of marine planktonic diatoms and the effects of different media on their growth and survival

Diatoms are the preferred live food of the protozoea stages of prawns. Due to seasonal variations, it is difficult to obtain continuous supply of diatoms and other algae throughout the year. Therefore mass culture of diatoms is necessary. At attempt was made to culture planktonic diatoms and to study the effect of Allen and Nelson media, Simon media, Vitamin B12 and treated sewage water media on their growth and survival. Navicula sp showed better growth in Allen and Nelson media, Coscinodiscus and Chaetoceros grew better in Simon media while Navicula sp and Coscinodiscus sp showed better growth in the combination of Allen and Nelson + Vitamin B12.

Culture of Moina micrura on various organic waste products

Moina micrura, a cladoceran species, is considered to be one of the best live food organisms for rearing the young larval stages of fish and prawn. Considering the importance of this species in hatchery operations the present study was undertaken to record its fecundity and life span and to culture it using different locally available organic waste products. In indoor culture, a maximum production of 2600 ind/1 and a minimum of 1050 ind/1 were obtained when treated with gram + maize oilcake and "till" oilcake respectively. In outdoor culture, a highest production of 6000 ind/1 was achieved with "Alsi" and "till" oilcakes and a lowest density of 1050 ind/1 with coconut oilcake and raw cattle dung was obtained with an inoculation rate of 5 ind/1.

Studies on the possible sources of microbial contaminations of processed fishery products

An attempt has been made in the present study to estimate and describe in detail the nature and extent of contamination of processed fishery products. In large scale prawn processing when the preprocess preparation is elaborate, the industry in India has found it advantageous to establish the primary processing centers away from the processing factories. The data collected have clearly indicated that if such processing centers are not properly organized there is a possibility of greater contamination of the products at this stage. The data collected during the course of this investigation have given the basis for the measures to be taken for the maintenance of bacterial quality of prawn during different stages of processing.

A study on the quality of prawns during processing in prawn-freezing factories

A study on the occurrence of defective pieces of prawns at three different stages of processing of headless shell on and peeled and deveined varieties was undertaken, each in one freezing factory. The average percentages of the defective prawns together with the standard deviation observed over a period of one year at the three stages are mentioned. Correlation is indicated between the occurrence of the defective pieces at the pre-freezing stage and those of earlier stages.

A histological study of the spermatogenesis in Ompok pabda (Hamilton-Buchanan 1822)

The present study deals with the histological analysis of testicular development in Ompok pabda. For the study, male gonads were collected month wise from January to September at Freshwater Station, BFRI, Mymensingh. From the analysis, 4 stages of sperm formation, namely, spermatogonia, spermatocytes, spermatids and spermatozoa, were distinguished. The percent distribution of spermatozoa was highest in July (about 92%). Maximum GSI value was 1.129±0.271 found in July. By analyzing the histology of spermatogenesis it was established that this species breeds once in a year.