Post-larval feeding of Clarias gariepinus (Burchell, 1802) on cultured zooplankton and artemia diets

The findings are presented of a study undertaken to provide baseline information that may be employed to develop a simplified hatchery technique for postlarval feeding of Clarias gariepinus on zooplankton cultured indoors in small aquaria. Three series of experiments were undertaken to identify the type and quantity of organic manure that would produce maximum densities of zooplankton in the shortest time in indoor cultures. Results suggest the possibility of the culture of natural zooplankton populations for use in larval feeding of C. gariepinus fry. Its effective hatchery application would bring about reduction in the unit cost per fingerling and ensure continuous hatchery operations even in the absence of Artemia cysts

Charles Henry Gilbert (1859-1928), Naturalist-in-Charge, and Chauncey Thomas, Jr. (1850-1919), Commanding: Conflict Aboard the U. S. Fish Commission Steamer Albatross in 1902

Charles Henry Gilbert (1859-1928) was a pioneering ichthyologist who made major contributions to the study of fishes of the American West. As chairman of the Department ofZoology at Leland Stanford Junior University in Palo Alto, Calif., during 1891-1925, Gilbert was extremely devoted to his work and showed little patience with those ofa different mindset. While serving as Naturalist-in-Charge of the U.S. Fish Commission Steamer Albatross during her exploratory expedition to the Hawaiian Islands in 1902, Gilbert engaged in an acrimonious feud with the ship's captain, Chauncey Thomas, Jr. (1850-1919), U.S.N., over what Gilbert perceived to be an inadequate effort by the captain. This essay focuses on the conflict between two strong figures, each operatingf rom different world views, and each vying for authority. Despite the difficulties these two men faced, the voyage of the Albatross in 1902 must be considered a success, as reflected by the extensive biological samples collected, the many new species of animals discovered, and the resulting publication of important scientific papers.

Morphometry, length-weight relationship and food and feeding habits of Otolithoides biauritus (Cantor, 1850) of Bombay waters

Thirteen morphometric and seven meristic characters, length-weight relationship and food and feeding habits of Otolithoides biauritus of Bombay coast (Maharashtra, India) were studied. Compared morphometric characters revealed positive allometric growth and high correlation ("r" ranging 0.898 - 0.996) between each other. Meristic characters were observed to be B sub(vii), D sub(1) 8-10, D sub(2) 27-31, P 17-20, V 5-7 and 7-10. Number of gill rackers on the first left gill arch ranged from 15 to 19. Length-weight relationship for both sexes together worked out to be W = 0.026, L super(2.646). The species is a predator, feeding mainly on motile Acetes, small fish and Loligo in order of preference.

Population dynamics and stock assessment of Koth (Otolithoides biauritus Cantor, 1850) along the north-west coast of India

MSY, growth, selection and mortality parameters of Otolithoides biauritus have been worked out from data collected by MFV Saraswati of CIFE, and length frequency data from Ferry Wharf, Sasson dock, and Versova fish landing centres of Bombay. Values of L infinity, K, and t omicron obtained from length frequency study are 1572 mm, 0.2633/yr and 0.0289 yr respectively, and of weight growth parameters are W infinity = 10067 g, K = 0.03904/yr and t omicron = 0.0137 yr. Selection parameters are L + 150 mm, t sub(r) + 0.4167 yr lc + 240 mm and t omicron = 0.6367 yr. Selection factor (K) for codent worked out to be 12. Based on Z = 0.6486, the MSY of O. biauritus off northwest coast of India is assessed as 1,802 tons which is slightly higher than the current catch level of 1,634 tons.

Exploitation of tunas in Ceylon's coastal waters

Ceylon’s fishery for the tunas is presently limited to the coastal waters which in the present context have an off-shore limit of 15 miles and our contribution to the world tuna production is a little over 1%. Four varieties of tuna are largely exploited in the coastal waters. Of these, Baleya or the skipjack (Katsuwonus pelamis Linn. 1758) is the predominant variety followed by attavalla or mackerel tuna (Euthynnus ajfinis, Cantor, 1850), kelawalla or yellowfin (Thunnus albacares, Bonnaterre, 1788) and alagoduwa or frigate mackerel (Auxis thazard Lacepede, 1802). Other varieties like the thora-baleya or bonito (Sarda orientalis) and asgedi kelawalla or big eye tuna (Thunnus obesus) are also landed frequently but in extremely small quantities. Figure 1 illustrates the relative composition of the tuna varieties in the catch and their percentage composition further sub-divided according to the type of effort applied. It is evident that Ceylon's coastal fishery for tunas is greatly influenced by the production of smaller varieties of the tunas.