International Journal of Fisheries and Aquatic Studies
2016, Vol. 4, Issue 6, Part F
Study of the population parameters of the bigeye grunt, Brachydeuterus auritus (Valenciennes, 1831) in Ghanaian coastal waters and its implications for management
Author(s): Samuel KK Amponsah, Patrick K Ofori Danson and Francis KE Nunoo
Abstract: Some vital population parameters of the bigeye grunt,
Brachydeuterus auritus (Valenciennes, 1831), within Ghana’s coastal waters were evaluated based on monthly pooled length-frequency data from June 2014 to January 2015 using the FiSAT Tool II. The estimated growth parameters from 1675 samples were: asymptotic length (L∞) = 16.28 cm standard length, growth rate (K) = 0.78 per year, growth performance index (ɸ) = 2.315, longevity (t
max) = 4 years, theoretical age (t
o) = -0.24 years and the ratio of Z/K = 1.26. The length at first capture (Lc
50), length at first maturity (Lm
50) and length at first recruitment (Lr) were estimated at 3.95 cm, 10.9 cm, and 3.5 cm respectively. The observed recruitment pattern portrayed an absence of recruitment overfishing while the ratio of Lc
50/L∞ (0.24) showed the presence of growth overfishing. Total mortality rate (Z), natural mortality rate (M) and fishing mortality rate (F) were estimated at 3.21 per year, 1.73 per year and 1.48 per year, respectively. The current exploitation rate (E
current) was 0.46 whereas the maximum exploitation level (E
max) was 0.48. The yield isopleth indicated that small sized
Brachydeuterus auritus are harvested at low fishing effort level – characteristic feature of a fishery at the developing stage. Results from the study indicated that Brachydeuterus auritus stock is vulnerable to collapse in the absence of urgent management interventions such as mesh size regulations and monitoring of fishing efforts.
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How to cite this article:
Samuel KK Amponsah, Patrick K Ofori Danson, Francis KE Nunoo. Study of the population parameters of the bigeye grunt, Brachydeuterus auritus (Valenciennes, 1831) in Ghanaian coastal waters and its implications for management. Int J Fish Aquat Stud 2016;4(6):413-419.