Macrobrachium macrobrachion (Herklots, 1851) Class Structure and Sex Ratio in Luubara Creek, Ogoni Land, Niger Delta, Nigeria

Abstract: Macrobrachium macrobrachion class structure and sex ratio was studied in Luubara creek of Ogoni land in the Niger Delta area of Nigeria for a period of two years (January, 2006 to December, 2007. Majority of male shrimps were found in the 8 to 16 mm class. In 2006, the size class (8-16 mm) recorded 232 shrimps and constituted 32.08% of the sample population. However, in 2007 most of the male shrimps occurred in the 12-16 mm class, (157 shrimps) and constituted 28.91% of the sample population. In the females, the dominant size class was 8 to 16 mm. In 2006, a total of 324 females were observed in this size and this constituted 49.24% of the sample population. In 2007, a total of 170 female shrimps were obtained in the 8 to 12 mm size class and this constituted 38.20% of the population. There were no female shrimps caught in the 24 to 28 mm class during the study period. Amongst the berried females most of shrimps were found in the size class of 8-20 mm. In 2006 there were 274 berried females in the 8-12 mm group and this constituted 51.40% of the sample population. In 2007 a total of 167 berried females were caught in 8-12 mm group and this constituted 47.87% of the sample population. The sex ratios of shrimps in Luubara creek were variable. There were more females than males. The overall male to female ratio was 1:1.6. It was only in the month of October 2006 that the numbers of male were more than the female with a ratio of 1 male: 0.9 female. The male to female ratio was more than 1:2 in four months namel

AGRICULTURE AND BIOLOGY JOURNAL OF NORTH AMERICA Growth, mortality and recruitment of Periopthalmus barbarus (Linneaus 1766 ) in New Calabar River, Nigeria

ABSTRACT A sample size of 1572 was collected in the study and estimates of the growth, mortality and recruitment of Periophthalmus barbarus over a twelve month period in New Calabar River Nigeria. Applying the Von Bertalanffy function gave the value of the growth coefficient (K) as 0.65yr -1 ,while length infinity (L oo ) was 15.28cm by Shephard's method.The Powell Wetheral's plot gave L oo as 10.73cm, Z/K 0.569 and the function Y=6.84+(-0.637)*X. Length at age (t o ) was 0.16. The growth performance index (ǿ) was 2.181.From length converted catch curves total mortality (Z) was 2.03 yr -1 , natural mortality (M) 1.68 yr -1 and fishing mortality (F) 0.35 yr -1 . Exploitation rate was 0.17 and Emax 0.421. Length at first capture from relative yield/recruit analysis (knife edge ) (Lc) was 0.76cm and Lc/ L oo was 0.050

Some Growth Parameters of Macrobrachium mcrobrachion (herklots, 1851) from Luubara Creek in Ogoni Land, Niger Delta, Nigeria

Abstract: Some Growth parameters of Macrobrachium mcrobrachion from Luubara Creek in Ogoni Land, Niger Delta, Nigeria was studied for a period of two years (January, 2006 -December, 2007. The parameters were evaluated using different applications in the FiSAT package such as the Powell-Wetheral plot; the ELEFAN 1 Scan, and the Non-Seasonalized Version of the Von Bertalanffy growth function (VBGF) to ensure accuracy. Powell-wetheral plot gave estimates of L4 as 81.53 mm TL), K was 2.06 per year, Z/K was 1

A study of the length – weight relationship and condition factor of Pseudotolithus elongatus (Browdich, 1825) from Bonny Estuary Niger Delta, Nigeria

The length–weight relationship and condition factor of Pseudotolithus elongatus from Bonny estuary was studied for a period of twelve months. A total of one thousand seven hundred and twenty five (1725) fish specimens were used. The initial growth constant (a) was 0.0047 (combined), 0.0047 (males) and 0.048 (females). The length exponent values (b) were 3.1675 (combined), 3.1566 (males) and 3.1569 (females). The correlation growth coefficient values (r2) were 0.84 (combined), 0.81 (males) and 0.84 (females). Values for the mean condition factor ranged from 0.76±1.87 (June) to 0.88±.1.1145 (March). Pseudotolithus elongatus exhibited an allometric growth. There was a positive correlation between length and weight of both sexes. P. elongatus was also in a good condition.Keywords: Fish, length–weight relationship, condition factor, Bonny estuary, Nigeria

AGRICULTURE AND BIOLOGY JOURNAL OF NORTH AMERICA Reproductive biology of Periopthalmus barbarus (Linneaus 1766 ) in new Calabar River, Nigeria

ABSTRACT Periophthalmus barbarus (n= 600) sampled over a twelve month perio

2010): Seasonal variation of some physical and chemical parameters of Luubara creek, Ogoni land

Abstract: The seasonal variation of some physical and chemical conditions in Luubara creek of Ogoni land in the Niger Delta area of Nigeria was studied for a period of two years (January, 2006 to December, 2007 26.45ºC and 26.90 (26.70±0.19ºC). The pH recorded in the dry season was between 6.01 and 6.13 (6.08±0.05) while the wet season values were 6.55-6.87 (6.74±0.14). The total alkalinity in the dry season range from 9.50 to 9.72 mg/L with a mean of 9.59±0.9 mg/L. This was higher than the wet season which was between 6.73 and 9.34 mg/L (7.90±1.08 mg/L. The electrical conductivity in the dry season was within the range of 13.39 and 22