TITLE:
The Recruitment Pattern of Liza falcipinnis from Elechi Creek, Upper Bonny, Niger Delta, Nigeria
AUTHORS:
Awoteinm Dateme Isaiah George, Jasper Freeborn Nestor Abowei
KEYWORDS:
Mullet, Recruitment Pattern, Elechi Creek, Niger Delta
JOURNAL NAME:
Open Access Library Journal,
Vol.5 No.4,
April
18,
2018
ABSTRACT: The Recruitment Pattern of Liza falcipinnis from Elechi creek of Upper Bonny, Niger Delta, Nigeria was studied from (March 2009-January 2010). The pattern showed all year round recruitment with two peaks (one major and one minor) during the period of the study. The parameters obtained were L∞ = 19.96, K = 0.40 y﹣1, C = 0, WP = 0, to = 0. The C indicates the amplitude of seasonal growth oscillations (that is, the magnitude of the growth patterns) and has values ranging from 0 to 1.0. Winter Point (WP) indicates the times of the year during which growth is minimal. The percentage recruitment for the different months were: March 2009 (15.0%); April (23.40%); May (14.0%); June (11.3%); July (10.0%); August (7.30%); September (1.8%); October (0.5%); November (2.2%); December (8.0%) and January 2010 (6.0%). The exploitation rate (Emax) that gives maximum relative yield-per-recruit was 0.424. The exploitation rate at which marginal increase occurred in the relative yield-per-yield was 10% of its value at E = 0, whereas (E0.1) was observed to be 0.357. The exploitation rate (E0.5) which corresponds to 50% of the virgin (that is, the unexploited stock) relative biomass-per-recruit was estimated to be 0.279. The mean ratio of length-at-first capture (L∞) and asymptotic length (L∞) was 0.060, while that of natural mortality (yr﹣1) and growth rate (yr﹣1) was 1.00. Yield per increased gradually with increase in exploitation and Biomass per recruit declined with increase in exploitation. An all year round recruitment, with one high pulse arid a low pulse was established for the species. Research should be carried out to ascertain the influence of environmental factors on the growth and recruitment of the species.