An aerial survey for surface tuna resources in the seas around Ceylon

An aerial survey of the off shore range around Ceylon, for a quick evaluation of the potential surface tuna resources, for commercial exploitation, was organised by Mr. Manuel R. Cintas of Ocean Blazer Inc. (Commercial tuna), San Diego, California and his associate Mr. R. Perera. The organisers offered, through the Hon'ble Minister of Fisheries, to take an officer of the Fisheries Research Station, Ceylon, as an observer and the author participated in that capacity. Dr. V. Arkely served as the photographer. The survey period was within the South-West monsoon season and extremely bad weather with high speed winds were experienced particularly off the North-West and South coasts. Except during these two trips, an average altitude of 1,000 ft. and a flying speed of 110-115 m.p.h. were maintained. The program was to cover the off shore range between 15 miles and 50 miles, from shore. The total number of hours of flying was eighteen. Details of the flight plan are shown in figure 1.

Marketing of small indigenous species of fish (SIS) in three selected fish markets of Mymensingh

A socio-economic survey was conducted round the year in three fish markets at Mymensingh, Bangladesh. The selected markets were categorized as rural market (Sutiakhali market), a peri-urban market (Kamal Ranjeet market, BAU) and an urban market (Notun Bazar market, Mymensingh town). It was learnt from the survey that the availability of Small Indigenous Fish Species (SIS) declined to a great extent over the last few years and at presently many of such fish species are either threatened or at the edge of extinction. The supply of SIS was highest in KR market (37% of total) and more or less similar in Notun Bazar and Sutiakhali fish market (25 and 27% respectively). The total supply of SIS fluctuated from 25% to 35% throughout the year in these markets. About 48 SIS were found in the sampled markets over the survey period. The highest number of species (45) was found in KR market followed by Notun Bazar (42) and Sutiakhali (37) fish markets. During the survey, three critically endangered species namely, schilbid catfish, garua catfish and rita were found in these markets. Beside these, other 11 and 10 species were listed to be endangered and vulnerable respectively. The biodiversity of 21 SIS found in three markets were no threat at all. Three species (guntea loach, Indian glass barb and flying barb) were 'data deficient' as reported by the IUCN Red Book (IUCN-Bangladesh 2000). From the supply point of view small prawn, spotted snakehead, stinging catfish, pool barb, striped dwarf catfish, Gangetic mystus, walking catfish and tank goby were the prominent fish. The least available species found in this survey were lesser spiny eel, barred spiny eel, Gangetic ailia, freshwater garfish, zig-zag eel, flying barb, Ganges river sprat, freshwater river shad and dwarf gourami. The weight of SIS available in Notun bazar was highest and nearly double than other two markets. There was no significant difference recorded in the supply of SIS in Sutiakhali and KR markets. The average monthly SIS supply was 185, 192 and 467 kg in KR, Sutiakhali and Notun Bazar, respectively; therefore, the cumulative average supply was 844 kg per month in three markets. The price of SIS ranged widely from taka 50-450/kg depending on species, location of market, time of purchase and the condition of fish. In general small prawn, ticto barb, dwarf gourami, Gangetic leaffish, and Annandale loach were sold at a lower price (ranged taka 50-100/kg) and these species could be considered at the bottom of the market-price list. Other SIS like walking catfish, climbing parch, butter catfish, cotio and schilbid catfish valued as highest price (ranged taka 150-450/kg). There was no specific marketing chain for SIS in Mymensingh region. The components of marketing channels and their expansion varied with seasons and locations. The general pattern, however, was as this - after buying fish from fish farmer/fishermen, middlemen (locally known as Foria) used to buy fish to wholesale market and sell to the wholesalers. The retailers used to buy fish from wholesaler through auction to the highest bidders. The retailers then send the fish to particular market where the fish reached the consumers. The livelihood strategy of SIS retailers in three fish markets showed that socio-economic constraints such as low income, poor educational background, low economic status and lack of capital are the main constrains [sic]. Most of the retailers proposed that government should control the fish price throughout the year, so that the producers can get reasonable and stable price. Construction of cold storage and preservation facilities at market sites, improvement of road and communication, improvement of physical market facilities and reduction of market chain is essential. Credit facilities, improvement of their standard of living, health and sanitary condition, housing condition, children education and access to drinking water facilities were identified as additional aspects to improve socio-economic condition of SIS retailers.

Population dynamics and management of yellowfin tuna (Thunnus albacares) of the Oman Sea

The Yellowfin tuna was caught more than all other species in the southern waters of Iran (24000 tons in 1998). In order to come up with the responsible fishing pattern, there was a need to identify some of the biological characteristics and population dynamic parameters. This thesis was the first which covered the whole Yellowfin tuna distribution in the Oman Sea, included the fishing grounds of Berris, Ramin, Chabahar, Pozm and Jask. The data during 1998-99 from different fishing grounds were polled. Based on the exponential relationship between length and weight in the size range 38-173 Cm, the relationship (W=aL^ b) was calculated as W=0.000012L ^ 3.0831). The mean fork length,head length,girth and weight were calculated respectively 84.15 Cm, 23 Cm, 53 Cm, and 11828 g. Length infinity was estimated 189 Cm with growth parameters of 0.42 per year. Growth performance index was 4.18 which was in agreement with the findngs of the other studies in the Indian and Pacific Oceans. The mortality parameters and exploitation rate were estimated as below: Z = 1.75-1.85 M=0.6 F=1.25 E=0.68 Occurence of empty stomach was high (60%) in the speciemens obtained from the Oman Sea. Purpleback flying squid (Sthenoteuthis oualaniensis) was the most dominant prey species observed in the study (57% in females and 60% in males), occurrence of teleost fishes were found to be the second (38% in males and 42% in females). Crabs also were identified in the specimens(1-2%). The study on sex ratio indicated that males were predominant at all sizes above 120 Cm fork length. 50.82% of specimens were males and 49.18% females. The monthly gonadosomatic index was deriven higher values during January to June which could be indicated as spawning period.