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Biometric Indices and Condition factors of Pomadasys jubelini (Cuvier, 1830) from Obuama Creek, Nigeria Olaniyi Alaba Olopade; Henry Eyina Dienye; Cynthia Chigazu Okonkwo
ILMU KELAUTAN: Indonesian Journal of Marine Sciences Vol 25, No 2 (2020): Ilmu Kelautan
Publisher : Marine Science Department Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (366.439 KB) | DOI: 10.14710/ik.ijms.25.2.45-52

Abstract

Biometric indices of Pomadasys jubelini from Obuama Creek, Rivers state, Nigeria were investigated using length frequency distributions (LFDs), length-weight relationships (LWRs), length-length relationships (LLRs), condition factors (allometric, KA, Fulton’s, KF and relative, KR). Specimens were captured in a stretch of the creek from March to September 2019. A total of 229 specimens were examined with the total length (TL) and weight (W) ranging from 8.7 to 50.4 cm and 8.7 to 834.5 g respectively. The standard length (SL) ranged from 5.3 to 46.8 cm, fork length (FL) was between 6.5 to 48.7 cm and the girth length (GL) varied from 4.7 to 38.7 cm. The relationships of weight-length showed a negative allometric growth pattern with a value of "b" of 2,666. Fulton's condition factor (KF) ranged from 0.10 to 5.45, with an average of 1.21±0.66 indicating perfect wellbeing for the species. The LLR's allometric coefficient ' b ' between TL vs. FL and TL vs. GL showed positive allometric growth, while SL vs. FL, SL vs. TL, SL vs. GL, and GL vs. TL showed negative allometric growth, although the values were close to 1. These findings also provided some new and updated information on some of the morphometric characters of Pomadasys jubelini in Obuama Creek that could be useful for fisheries management and fish species protection measures in the creek and adjacent habitats.  
ESTIMATION OF GROWTH, MORTALITY, AND EXPLOITATION STATUS OF NURSE TETRA (Brycinus nurse) AND TRUE BIG SCALE TETRA (Brycinus macrolepidotus) (FAMILY: ALESTIDAE) FROM THE NEW CALABAR RIVER, NIGERIA Olaniyi Alaba Olopade; Henry Eyina Dienye; Uzoma C Nworgu
Indonesian Fisheries Research Journal Vol 25, No 2 (2019): (December) 2019
Publisher : Research Center for Fisheries

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (676.966 KB) | DOI: 10.15578/ifrj.25.2.2019.113-122

Abstract

This study aimed to determine the growth patterns, mortality, and exploitation status of two species of Alestidae in the New Calabar River, Nigeria. For this purpose, fish samples were collected monthly from three landing sites from the local fishermen using gill nets (mesh sizes: 15-25mm), beach seine (mesh sizes: 2.3-10mm), and cast nets (mesh sizes: 15 -25mm). The length-weight relationship revealed exponent “b” value for Brycinus nurse was 3.54 and 3.21 for Brycinus macrolepidotus while the condition factors were 1.08 and 1.02 for Brycinus nurse and Brycinus macrolepidotus respectively. The growth parameters of Brycinus nurse asymptotic length (L) and growth coefficient (K) were 24.46 cm and 0.52 yr-1, respectively, while those for Brycinus macrolepidotus L was 28.88 cm and K was 0.22 yr-1. The reproductive load (L50/L) ratio was found to be 0.59 and 0.61 for B. nurse and B. macrolepidotus, respectively. Exploitation rate (E) for B. nurse was 0.26 and 0.11 for B. macrolepidotus while length-at-first capture (Lc) was 14.49 cm for B. nurse and 17.64 cm for B. macrolepidotus. The natural mortality was greater than the fishing mortality for both species and Logistic regression of the probability of capture routine values recorded for B. nurse were higher than that of B. macrolepidotus. Maximum exploitation rate (Emax) was less than 0.5 for both B. nurse (0.41) and B. macrolepidotus (0.42). These values were close to the maximum allowable limit; therefore, the species may be unsustainable when fishery intensifies in the future. To ensure sustainable exploitation of the two Alestid species in the area, fishing effort should be regulated.