Changes in the hydrometeorological regime in the Pacific Southwest [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Selected hydrometeorological (HM) data for the Pacific Northwest and atmospheric and North Pacific sea-surface temperature (SST) data are examined for three successive periods that are subsets of the historical record to estimate if their characteristics have changed.

Mortality rates of the Poovalan prawn (Metapenaeus dobsoni) along the southwest coast of India with a note on the dynamics of its population

The annual instantaneous total mortality coefficient (Z) for the prawn Metapenaeus dobsoni has been estimated to range from 0.8 to 5.14 by the cumulative catch curve method. Different methods used in the study resulted in wide ranging values of natural mortality (M) (0.6 to 2.303), but the yield per recruit model when superimposed with the absolute yield values revealed the right order to be > 2. The biologically optimum yield of about 18 thousand tons is obtained for an effort of 2,702 trawlers per day for 215 fishing days when the annual exploitation ratio (E) is about 52%.

Reproductive biology of the blue spot mullet Valamugil seheli (Forskal) from Mangalore Region, southwest coast of India

The blue spot mullet Valamugil seheli spawns once a year between August and February with peak spawning during October - November. Males attain maturity at 250.5 mm and females at 256.5 mm total length. Males outnumbered females in the commercial catches, although the sex-ratio (M:F=1:0.90) in the population showed no significant deviation. The fecundity of this species varied from 108378 to 910350 eggs with an average of 327944. Linear relationships were found between fish length, gonad weight and fecundity; and between fish length, fish weight and ovary weight.

Distribution of wave heights in Phitti Creek during southwest monsoon

A waverider buoy was deployed in Phitti Creek (24°33'N; 67°03'E) for wave measurements during April-July 1986. Using Tucker's method wave records were calculated in terms of significant wave height (Hs) and Maximum Wave Height (Hmax). For each parameter weekly mean and standard deviation values were also computed for statistical analysis. For Hs the lowest mean value of 0.8m and for Hmax the lowest mean value of 1.51m were observed in the fourth week of April whereas the highest mean value observed for Hs was 3.02m and for Hmax was 4.94m in the fourth week of June, 1986.

Water quality parameters of coastal shrimp farms from southwest and southeast regions of Bangladesh

The impacts of shrimp farming on water quality and effluent loading of shrimp farms in southwest (Khulna) and southeast (Cox's Bazar) regions of Bangladesh was investigated during March-August and August-October season, respectively. Water salinity fluctuated from 3.0 to 15.0 ppt in the southwest, whereas it was between 2.5 to 20.0 ppt. in southeast region. Total ammonia nitrogen as recorded in most farms of Cox's Bazar region was higher (0. 1160.438 mg/L) than the recommended level of shrimp farming. Mean values of total ammonia nitrogen and total nitrogen at the outlet of shrimp farms were higher than those of inlet in both regions. Mean values of phosphate phosphorus and total phosphorus at outlet were lower than inlet except in harvest time of Penaeus monodon. Total suspended solids were deposited on the bottom of shrimp farms in both regions, which resulted in higher concentration in inlets than outlets in both regions.

Standing stock of three species of demersal fishes from southwest coast of India

Standing stock of three principal demersal fishes of the inshore waters off Mangalore was assessed. The assessment was based on fortnightly samplings conducted in an area extending over ca 850 km². The data gathered was computed employing Alverson's methods. The standing stock of Nemipterus japonicus, Saurida tumbil and Grammoplites scaber indicates that this area supports good quantities of these fishes and if properly exploited, will sustain a profitable demersal fishery.