Stock assessment of the Tigertooth croaker, Otolithes ruber (Bloch & Schneider, 1801) from the commercial prawn trawl fishery by-catch in coastal Kenya
Fatuma A. Mzingirwa
Jane M. Nyamora
Johnstone O. Omukoto
Paul Tuda
Abstract
Commercial bottom prawn trawling has been reported to generate a higher proportion of by-catch of up to 70% in Kenya. The Tigertooth croaker, Otolithes ruber is one of the species caught in large quantities as commercial by-catch and also by artisanal fishers. This has led to growing concern that the species could be at risk of over-exploitation. The purpose of this study was to carry out a stock assessment of O. ruber. Stock assessment parameters were estimated using ELEFAN with the generic algorithm as included in the R package TropFishR. The length-converted catch curve and the length-based yield per recruit model were employed. The exploitation rate (F/Z = 0.71) indicates that the stock is overfished based on the length-converted catch curve. The current fishing mortality (F = 2.3) based on the catch curve is larger than the reference level ( = 1.1) based on the yield per recruit analysis and also indicates that the stock is overfished (= 2.09). To reverse the current trend of exploitation, improved management of the stock is required, which should include further studies on other by-catch species and the generation of data to capture the whole fishery for a better estimation of stock status.
Mzingirwa F.A., Nyamora J.M., Omukoto J.O. and Tuda P. (2021) Stock assessment of the Tigertooth croaker, Otolithes ruber (Bloch & Schneider, 1801) from the commercial prawn trawl fishery by-catch in coastal Kenya. Western Indian Ocean Journal of Marine Science 19(2): 149-165. 10.4314/wiojms.v19i2.11
@article{Mzingirwa2021,
Title = {Stock assessment of the Tigertooth croaker, Otolithes ruber (Bloch & Schneider, 1801) from the commercial prawn trawl fishery by-catch in coastal Kenya},
Author = {Mzingirwa, Fatuma A. and Nyamora, Jane M. and Omukoto, Johnstone O. and Tuda, Paul},
Editor = {},
Journal = {Western Indian Ocean Journal of Marine Science},
Year = {2021},
Pages = {149-165},
Volume = {19},
Doi = {10.4314/wiojms.v19i2.11},
Abstract = {Commercial bottom prawn trawling has been reported to generate a higher proportion of by-catch of up to 70% in Kenya. The Tigertooth croaker, Otolithes ruber is one of the species caught in large quantities as commercial by-catch and also by artisanal fishers. This has led to growing concern that the species could be at risk of over-exploitation. The purpose of this study was to carry out a stock assessment of O. ruber. Stock assessment parameters were estimated using ELEFAN with the generic algorithm as included in the R package TropFishR. The length-converted catch curve and the length-based yield per recruit model were employed. The exploitation rate (F/Z = 0.71) indicates that the stock is overfished based on the length-converted catch curve. The current fishing mortality (F = 2.3) based on the catch curve is larger than the reference level ( = 1.1) based on the yield per recruit analysis and also indicates that the stock is overfished (= 2.09). To reverse the current trend of exploitation, improved management of the stock is required, which should include further studies on other by-catch species and the generation of data to capture the whole fishery for a better estimation of stock status.},
}
TY - JOUR
AU - Mzingirwa, Fatuma A.
AU - Nyamora, Jane M.
AU - Omukoto, Johnstone O.
AU - Tuda, Paul
TI - Stock assessment of the Tigertooth croaker, Otolithes ruber (Bloch & Schneider, 1801) from the commercial prawn trawl fishery by-catch in coastal Kenya
T2 - Western Indian Ocean Journal of Marine Science
PY - 2021
SP - 149-165
VL - 19
DO - 10.4314/wiojms.v19i2.11
AB - Commercial bottom prawn trawling has been reported to generate a higher proportion of by-catch of up to 70% in Kenya. The Tigertooth croaker, Otolithes ruber is one of the species caught in large quantities as commercial by-catch and also by artisanal fishers. This has led to growing concern that the species could be at risk of over-exploitation. The purpose of this study was to carry out a stock assessment of O. ruber. Stock assessment parameters were estimated using ELEFAN with the generic algorithm as included in the R package TropFishR. The length-converted catch curve and the length-based yield per recruit model were employed. The exploitation rate (F/Z = 0.71) indicates that the stock is overfished based on the length-converted catch curve. The current fishing mortality (F = 2.3) based on the catch curve is larger than the reference level ( = 1.1) based on the yield per recruit analysis and also indicates that the stock is overfished (= 2.09). To reverse the current trend of exploitation, improved management of the stock is required, which should include further studies on other by-catch species and the generation of data to capture the whole fishery for a better estimation of stock status.
ER -
Details
Datum02.04.2021
JournalWestern Indian Ocean Journal of Marine Science