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Abstract
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Article Information:
The Age and Growth of Callinectes amicola (De Rochebrune, 1883) from Okpoka Creek, Niger Delta, Nigeria
J.F.N. Abowei, A.D.I. George and S.N. Deekae
Corresponding Author: Abowei Jasper
Submitted: 2009 August, 26
Accepted: 2009 Sept., 09
Published: |
Abstract:
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The Age and growth of Callinectes amicola from Okpoka Creek in the Niger Delta area of Nigeria
was studied for a period of one year (January – December 2007).The size classes 30–39.9mm and 40–49.9mm
constituted the highest w ith 31.0% and 31.5% respectively. Very small size class below 10mm was completely
absent and largest size group (70–79.9mm) were very few (0.2%). The results of the modal length-at-age
revealed that all the sexes of Callinectes belonged to the age groups 1 to 3 years. Four year classes with modal
classes ranging from 6.7–68.3mm for males; 5.0–78.3mm for female and 5.8–75.8mm for combined sex. The
annual carapace length increment was highest in year class 1+ and declined with time for both sexes and
combined. The absolute increment was: male (17.5mm for 1–2y, 14.1 mm for 2–3y and 20.53mm annual
mean); female (18.3 for 1–2y, 10.8 for 2–3y and 24.43 annual mean) and combined (18.3mm for 1–2y,
12.5mm for 2–3y and 24.43mm annual mean). Relative increment was male (47.7% for 1–2y, 26.0% for 2–3y
and 36.85% annual mean); female (37.2% for 1–2y, 16.0% for 2–3y and 26.60% annual mean) and combined
(40.7% for 1–2y, 19.7% for 2–3y and 30.20% annual mean). Instantaneous rate of increase was male (0.390
for 1–2y, 0.231 for 2–3y and 0.311 annual mean); female (0.316 for 1–2y, 0.148 for 2–3y and 0.232 annual
mean) and combined (0.341 for 1–2y, 0.180 for 2–3y and 0.261 annual mean). Powell–Wetherall plot was L∞
(61.80mm), K (0.995 y-1) and Z/K (1.694). The length at age data was L∞ (61.80mm), K (2.10 y-1), to (1.220),
φ (3.90) and Rn(0.122) ELEFAN 1 scans routine was L∞ (61.80), R (2.10), φ (3.90) and Rn (0.121). The nonseasoned
version of the Von Bertalanffy Growth Function (VBGF) was L∞ (87.305mm), K (0.636 y-1), to (0.889) and φ (3.685). The longevity or maximum age (Tmax) was 4.7 years. The overall growth parameters
obtained were: L∞ = 61.80, K= 1.244y-1, to = 1.0545, Z/K = 1.694, R = 0.995, φ =3.825 and Rn =0.121.
Key words: C. amnicola, age, growth Okpoka Creek, Nigeria, , ,
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Cite this Reference:
J.F.N. Abowei, A.D.I. George and S.N. Deekae, . The Age and Growth of Callinectes amicola (De Rochebrune, 1883) from Okpoka Creek, Niger Delta, Nigeria. International Journal of Animal and Veterinary Advances, (2): Page No: 73-82.
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ISSN (Online): 2041-2908
ISSN (Print): 2041-2894 |
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