Mahim Bay: a polluted environment of Bombay

Distribution of the marine life in relation to the extent of pollution at and outside Mahim Bay was studied. A poor marine fauna at stations A and B was associated with a relatively high intensity of pollution accompanied by high BOD and nutrients and low DO levels. A distinct deterioration in the marine life and water quality along the northern part of the bay as compared to the southern part was evident. An increasing trend in the marine fauna with decreasing intensity of pollution from inside to outside the bay was noticed.

Mass breeding of silver carp in a cement cistern with crude H.C.G.

The paper presents a resume on experiments carried on mass breeding of the silver carp Hypophthalmichthys molitrix in a cement cistern through administration of crude human chorionic gonadotropin. The experiments proves that human chorionic gonadotropin (H.C.G.) can be used for mass breeding of the fish in simple enclosures, with facilities of some input and output of water and a dose of 5 mg/kg and 18 mg/kg of body weight, for males and females respectively are required for the purpose. Observations were made by using pituitary glands in similar way. For successful breeding of about 80 kg female together, the expenditure towards cost of pituitary gland and H.C.G. are respectively 275 and 117 Rs.

Report on two types of leptocephalus-eel from Vellar Estuary (Bay of Bengal)

Two types of leptocephalus-eel, identified as ophichthyid larva and Muraenesox cinereus, collected from the Vellar estuary, India, are described. M. cinereus larvae are common in the estuary during November-January whereas ophichthyid larvae are very rare, collected on one occasion (January) only.

Soundings: the Newsletter of the Monterey Bay Chapter of the American Cetacean Society. 2014

Issues January - November/December 2014. (PDF contains 100 pages)

The study of the sea state data collected from Bay of Bengal during 1964-65

The wave data collected on board Ins Kistna from Bay of Bengal during July to August, 1964 and January, February and April, 1965 are presented. The wave parameters are analyzed and given in a form most suitable for model testing of ships. The variation of wave height with Beaufort number is remarkable. Wave periods from 2 to 10 seconds are observed with maximum frequency in the range of 2 to 5 seconds. The heights and period obtained are compared with those obtained by previous workers for the North Atlantic region and Bay of Bengal. The influence of the wave period 2 to 5 seconds on the rolling, pitching and heaving periods of medium size vessels is also discussed.

Larval ontogeny of a percichthyid fish, Synagrops philippinensis (Günther) in Kagoshima Bay, southern Japan

The larval ontogeny of a developmental series (1.2-8.3mm body length, BL) of Synagrops philippinensis from Kagoshima Bay, southern Japan is described and illustrated. The yolk was completely absorbed in larva of ≥1.5 mm BL. Notochord flexion commenced at about 3.5mm BL and was completed by about 4.0-4.5mm BL. S. philippinensis larvae were distinguished from their congeners based on melanophore patterns, head spination and fin spines and rays. Larvae of 7.5-8.3 mm BL were characterized by anteriorly serrated pelvic spine, two anal spines, nine inner preopercular spines and no melanophore on lateral side of the caudal peduncle; 7.0 to 7.5mm BL larvae by the above characters except serration on pelvic spine; and yolk-sac, pre-flexion, flexing and post-flexion larvae up to 7.0mm BL by unique melanophores on lower lobe of pectoral finfold/fin.

Population dynamics of the ribbon fish, Lepturacanthus savala (Cuvier 1829) from the north-eastern part of the Bay of Bengal

Population parameters of Lepturacanthus savala from the trawl catches in the north-eastern part of the Bay of Bengal, Bangladesh were investigated based on length frequency data, using complete ELEFAN computer program. The asymptotic length (Lα) and growth constant (K) were estimated to be 106.50 cm (total length) and 0.80/year respectively. Based on these growth parameters, the total mortality (Z) was estimated to be 1.89. The estimated values for natural mortality (M) and fishing mortality (F) were 1.08 and 0.81 respectively. The estimated value for the exploitation rate (E) using the length converted catch curve was 0.43. The recruitment pattern showed two peaks per year. The estimated sizes of L. savala at 25, 50 and 75% probabilities of capture were 57.49, 60.39 and 63.28 cm respectively. The estimated length weight relationship for combined sex was W=0.00093 TL(super)2.97

A survey of the plankton of Monterey Bay

The purpose of this paper is to add to the identification of planktonic forms found in Monterey Bay, and also to compare the composition and population fluctuation with findings of previous years.

Studies on the seasonal cycle of sea surface temperatures, salinities and phytoplankton in Puttalam Lagoon, Dutch Bay and Portugal Bay along the west coast of Ceylon.

The monthly average temperatures at Puttalam Lagoon, Dutch Bay, Portugal Bay towards Kovilmunai and Portugal Bay towards Pallugaturai showed a distinct annual cycle. The peak was in April and values gradually fell till September. There was a further gradual fall in temperature from October to January. The highest temperatures in all four stations were in April. The highest salinities in all the stations were from May to October i.e., during the south-west monsoon. The salinities at Dutch Bay and Portugal Bay were high in March and April corresponding to the highest temperatures reached during these months. Two maxima have been observed in phytoplankton production. A primary maximum in May-June and a secondary maximum in October. The primary and secondary maxima are due to the influx of nutrient laden waters from the rivers Kal Aru and Pomparippu Aru. The phytoplankton producing blooms were Rhizosolenia alata. Rhizosolenia imbricata, Chaetoceros lascinosus, Chaetoceros pervianus, Ch,aetoceros diversus, Coscinodiscus gigas, Thallasionema nitzschioides, Thalassiosira subtilis, Thallassiothrix frauenfeldii, Asterionella japonica, Sceletonema costatum, Bacteriastrum varians and Biddulphia sinensis. Sudden outbursts of a single species were common. These diatoms were species of Chaetoceros and Rhizosolenia, and Thallassiothrix frauenfeldii. Wide fluctuations have been observed in the distribution of phytoplankton but no definite conclusions can be drawn as the period of observation was only one year.

Studies on the seasonal cycle of sea surface temperatures, salinities, oxygen and phytoplankton in Koddiyar Bay, Trincomalee in relation to the shore seine fishery

In Sri Lanka waters, Durairatnam (1963, 1969) had reported on the seasonal variation of plankton at Puttalam lagoon, Dutch Bay, Portugal Bay and in the inshore and off shore waters off Colombo. Similar investigations were carried out at Koddiyar Bay especially in the estuarine waters where the three tributaries of the river Mahaveli empty their waters into the bay. The estuary is perennial. The fishes constituting the estuarine fisheries are mostly shallow water marine species which can tolerate considerable variations of salinities. Prawns and crabs also constitute a very valuable fishery in estuarine waters.

An analysis of records of gillnet fishing in Pilkington Bay, Lake Victoria

Among the commercially valuable species occurring in Lake Victoria the two endemic species of Tilapia, T. esculenta (Graham) and T. variabilis (Boulenger) still provide the basis for the fishery in many areas, though in some places the non-cichlid species are more important, for example in the Kagera river area where large numbers of Labeo victorianus and Schilbe mystus migrate seasonally into the river. Although certain species show these habitat preferences. Most of the coastline of Lake Victoria supports a wide variety of species, all of which contribute to the commercial fishery. Over the past ten years the East African Fisheries Research Organisation has fished experimentally a number of stations within a radius of fifty miles from Jinja. These stations have been selected so as to cover a variety of habitats which range from sheltered bays to exposed coastlines. The records discussed in this paper are the result of fishing operations carried out in Pilkington Bay over the period December 1954 to November 1956. This series of fishing operations was carried out in an attempt to assess the composition of the fish populations contained in this area. To this end a variety of nets of differing mesh sizes were used. Pilkington Bay is about ten square miles in extent and is an irregular and deep indentation on the north coast of Buvuma Island. It lies within the sleeping siclmess area where fishing by Africans is prohibited. When selecting an experimental fishing ground, it is important to have some idea of the amount of commercial fishing being carried out in the area. Throughout the period of this experiment a few African fishermen were seen operating illegally in the area, but it is unlikely that their efforts greatly affected the results obtained. Pilkington Bay was fished by E.A.F.R.O. in 1949 and 1950 (Lowe McConnell 1956) but since then till the present experiment, fishing in the area has been infrequent.

Oceanographic research in Delagoa Bay area: a progress report

Oceanographic research carried out in the Delagoa Bay (Mozambique) area in January 1982 confirms the presence of a cyclonic eddy influencing a total area of approximately 150 km x 80 km between the Mozambique Current and the 200 m isobaths. The bottom topography seems to play a major role in the generation of the eddy. Comparison with results of investigations carried out in the area from 1957 to 1980 suggests that the eddy is quasi-stationary.

Reproduction, age and growth of the kelee shad, Hilsa kelee (Cuvier, 1829) (pisces: fam. Clupeidae) with informations on its fishery in Maputo Bay, Mozambique

Age, growth and reproduction of H. kelee were studied, and a brief description of its fishery in Maputo Bay (Mozambique) is given. Most material was collected from gill net fisheries during 1977-1980, but some was taken from shrimp trawlers operating in the same area during 1980-1981. Main spawning takes place during October-January with a peak in December. There is also some evidence that spawning takes place during June-July. The size at first maturity was approximately equals 14-15 cm. Ageing was carried out using primary growth rings in the otoliths and length-frequency analysis of fish caught by shrimp trawlers. Von Bertalanffy's growth equation parameters were determined. Males and females grew in similar fashion. There are seasonal trends in the catch composition of the gill net fishery, showing high values during April to September and low during October to December.

Mortality rates estimates for Metapenaeus monoceros (Fabricius) of Maputo Bay

The species Metapenaeus monoceros in Maputo Bay recruits to the fishery almost all over the year, but the main recruitment occurs over a short period of time, each year, during April-May. Growth curves were constructed by following the progression of modes over a period of time. The von Bertalanffy growth parameters were estimated as L∞=31.9 mm and K(monthly)=0.25, for males, and L∞=48.3 mm and K(monthly)=0.14, for females (Brinca and Sousa, 1984). Using data on growth and length composition of the catches, the following methods were applied to estimate mortality rates of M. monoceros: estimation of natural mortality by using approximative methods; use of c.p.u.e. data; catch curves; cohort analysis; average age and length methods.

A study on growth of Metapenaeus monoceros (Fabricius) of Maputo Bay

Biological data on Metapenaeus monoceros has been regularly collected in Maputo Bay since 1968. The main objective of this report is to study growth as a function of the size, since this is one of the basic parameters for population dynamics. As the possibility of studying shrimp growth by modal progression analysis depends very much on the space-time configuration of sampling, the years 1968 and 1969 were chosen to study growth of the population available to the bottom trawl used by the fishing industry. In those years sampling was very frequent (twice a week) and the samples were collected from a rather small fishing area. Complementary data on the spawning, juvenile phase and recruitment to the fishery was used to establish the relationship between the different stages of the life cycle and to obtain an age/length key. Data on juveniles in estuaries was only available for 1969 and 1973.