Biometric indices and population parameters of three polynemid fishes from Batang Lassa Estuary of East Malaysia
The length-weight relationships (LWRs), condition factor (Kn), growth, mortality and exploitation status of three polynemid fishes, i.e., Filimanus xanthonema (Valenciennes, 1831), Polynemus melanochir (Valenciennes, 1831) and Polynemus paradiseus (Linnaeus, 1758) from Batang Lassa River estuary...
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Main Authors: | , , , |
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Format: | Article |
Language: | English |
Published: |
2021
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Subjects: | |
Online Access: | http://ir.unimas.my/id/eprint/36478/1/Khairul%20Adha.pdf http://ir.unimas.my/id/eprint/36478/ https://peerj.com/articles/12183/ |
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Summary: | The length-weight relationships (LWRs), condition factor (Kn), growth, mortality
and exploitation status of three polynemid fishes, i.e., Filimanus xanthonema
(Valenciennes, 1831), Polynemus melanochir (Valenciennes, 1831) and Polynemus
paradiseus (Linnaeus, 1758) from Batang Lassa River estuary were estimated. Fish
samples were caught during April 2019 to September 2020 using the ESBN (locally
called Gnian) having 1.25 to 4.00 cm mesh size. The total length (TL) and body
weight of each individual fish was measured to the nearest 0.1 cm and 0.01 g
respectively. The growth coefficients (b) for F. xanthonema, P. melanochir and
P. paradiseus, were 2.880, 2.717 and 2.724 with the R2 values 0.956, 0.972 and 0.936
respectively. Estimated growth coefficients indicated a negative allometric growth
pattern for all three threadfin fishes. To date, information regarding length-weight
relationships for F. xanthonema and P. melanochir is insufficient whereas the
information is available for P. paradiseus. About 40–48% of fishes exhibited flat or
thin body shape (Kn < 1), 48–50% were rounded or fat (Kn > 1) and only 1–3%
of fishes showed proportional body shape (Kn = 1). The growth parameters L∞, K
and ϕ’ were estimated at 15.75 cm, 0.95 yr−1 and 2.37 for F. xanthonema;
27.61 cm 0.87 yr−1 and 2.82 for P. melanochir; and 27.30 cm, 0.58 yr−1 and 2.64 for
P. paradiseus; respectively. The estimated natural mortality (M) included 2.10, 1.69
and 1.30 yr−1
; the fishing mortality (F) 0.57, 0.67 and 0.60 yr−1
; and exploitation
ratio (E) 0.21, 0.28 and 0.31 for F. xanthonema, P. melanochir and P. paradiseus
respectively. The study concluded that the stocks are still under exploitation (E < 0.5)
condition. However, the studied Batang Lassa estuary could be a potential nursery
ground considering the minimum lengths of 5.0, 3.8 and 4.0 cm for F. xanthonema,
P. melanochir and P. paradiseus respectively. Therefore, management initiatives are
needed to escape juvenile catches. |
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