Population dynamics of Sardinella aurita (Val., 1847) within Ghana’s coastal waters

Amponsah, Samuel K. K.; Danson, Patrick K Ofori; Nunoo, Francis Ke; Ameyaw, G.

doi:10.3329/ralf.v4i3.35103

Cited by 8 publications

(9 citation statements)

References 4 publications

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“…Comparatively, the lower natural mortality rate (M) estimated from the study confirms high fishing pressure on S. maderensis in Ghanaian coastal waters. Furthermore, fishing mortality rate (F) was found to be higher than the optimum fishing limit (F opt ), which re-echoes the incidence of intense fishing pressure on S. maderensis (Amponsah et al, 2016b).…”

Section: Discussionmentioning

confidence: 78%

Estimates of Population parameters for Sardinella maderensis (Lowe, 1838) in the coastal waters of Ghana

Amponsah¹,

Ofori-Danson²,

Nunoo³

et al. 2019

Greener J Agr Sci

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This study examined some population parameters of Sardinella maderensis landed along the eastern coast of Ghana, based on length-frequency data from June, 2014 to January 2015. Overall, 1401 samples of S. maderensis were measured for standard length and resultant data analysed with FiSAT II. The asymptotic length (L ∞) and growth rate (K) were 23.63 cm SL and 0.61 yr-1 respectively. The theoretical age at birth (t 0) and growth performance index (ϕ) were-0.284 yr-1 and 2.532 respectively. The recruitment pattern was continuous with two recruitment pulses. Total mortality rate (Z), natural mortality rate (M) and fishing mortality rate (F) were 2.96 yr-1 , 1.30 yr-1 and 1.63 yr-1 correspondingly. Fishing mortality rate surpassed the optimum fishing rate which showed that the assessed fish species is under high fishing pressure. The estimated exploitation rate (E curr) was 0.55, implying that the stock is over-exploitation. VPA outcome revealed higher harvesting rate on individuals with length between 10-11 cm. The spawning biomass which was below the 30% of unexploited biomass indicated future recruitment failure of the stock. As a result, urgent management interventions such as the application of biological reference points and mesh size regulations are urgently recommended for sustainable exploitation of Sardinella maderensis.

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Section: Discussionmentioning

confidence: 78%

Estimates of Population parameters for Sardinella maderensis (Lowe, 1838) in the coastal waters of Ghana

Amponsah¹,

Ofori-Danson²,

Nunoo³

et al. 2019

Greener J Agr Sci

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“…The feasible fish size for capture was obtained by the ratio of the LC50% value to the asymptotic length (L∞). And other opinions used length-at maturity (Lm) as the critical limit value (Hoggarth et al 2006;Amponsah et al 2016). The mean length size of the fish capture had been feasible if the ratio (LC50%/L∞) > 0.5.…”

Section: Methodsmentioning

confidence: 99%

“…The mean length size of the fish capture had been feasible if the ratio (LC50%/L∞) > 0.5. The estimation of the L∞ and Lm value was obtained by the formula (Pauly 1983;Hoggarth et al 2006;Amponsah et al 2016) as follows:…”

Section: Methodsmentioning

confidence: 99%

Growth aspect of squid (Loligo chinensis) from the Banyuasin Coastal Waters, South Sumatra, Indonesia

et al. 2020

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Squid (Loligo chinensis) played an important role in small scale fisheries in Banyuasin Coastal Waters, however, the information and publications were limited. This study aimed to estimate the length at first capture (LC50%), the length at first maturity (Lm), growth pattern and condition factor of L. chinensis from Banyuasin Coastal Waters of South Sumatra. The squids were observed for samples in April 2018 and March 2019 using a stationary lift net. During the observation, the squid measurement was conducted on 1179 individuals. The mantle length ranged was 40-210 mm and their body weight ranged was 2-42 gr. The value of LC50%, Lm and ½L∞ were obtained at 103 mm, 147 mm, and 110.5 mm respectively. The analysis results of the length-weight relationship (W = 0.0145L1.4618, R2 = 0.9265 and P < 0.05) showed that their growth pattern was negative allometric (b < 3). The mean relative condition factor (Kn = 1.01) above the critical value limits (K=0.56) confirmed that the environmental condition of Banyuasin Coastal Waters suitable for the L. chinensis growth. However, should be careful with their length size of the squid catch were not feasible in the capture.

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“…The position of the major recruitment peak was in line with traditional knowledge of local fishermen. Furthermore, the strong presence of recruits evinced by the recruitment pattern suggests that recruitment within Brachydeuterus auritus stock is still functional [24].…”

Section: Discussionmentioning

confidence: 99%

“…Probable causes for the observed variation include geographical locations, genetic makeup and environmental factors [24]. More so, in relation to the length at first maturity, lower length at first capture revealed that the juveniles are harvested before adding to the biomass of the stock which is a feature of growth overfishing.…”

Section: Discussionmentioning

confidence: 99%

Population Dynamics of Bigeye Grunt, Brachydeuterus auritus (Valenciennes, 1831) in Ghana and Management Implications

Amponsah¹,

Abdulhakim²,

Ofori-Danson³

et al. 2017

Fish Aquac J

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Population dynamics of Brachydeuterus auritus harvested from Ghana's coastal waters was assessed following previous indications that this important species is collapsing. In view of this, a total of 849 samples of B. auritus were collected from February 2016 to January 2017, measured for total lengths and examined using FiSAT II. The mean length was 13.7 cm with a growth pattern of 2.8. The asymptotic length (L∞) and growth rate (K) were 21.53 cm and 0.67 yr -1 respectively portraying that this species is a fast-growing species. The lengths at first maturity and capture were calculated as 14.4 cm and 6.02 cm respectively which indicated the presence of growth overfishing. The critical length at capture (Lc=0.28) was lower than 0.5, supporting the earlier assertion that the investigated fish species is plagued with growth overfishing. Natural mortality rate (M=1.44/yr) was higher than fishing mortality rate (F=1.22/yr) an indication that small sized fished fishes were largely harvested. The recruitment layout was unremitting throughout the year with two major peaks showing the presence of strong recruitment into the stock -a strategy to avert extinction of its species. However, the exploitation rate (E=0.46) was slightly lower than the E max (0.52) showing that the biomass of the investigated stock could surpass the maximum sustainable yield (E max ) if necessary fishery management options are not put in place. Furthermore, using the Quadrant rule, the investigated stock was categorized as developing, hence any unsustainable increase in fishing efforts could facilitate growth overfishing leading to its collapse. Therefore, to ensure sustainable exploitation and contribution to protein requirement for coastal community households, relevant fisheries measures are advocated.

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Population dynamics of Sardinella aurita (Val., 1847) within Ghana’s coastal waters

Cited by 8 publications

References 4 publications

Estimates of Population parameters for Sardinella maderensis (Lowe, 1838) in the coastal waters of Ghana

Estimates of Population parameters for Sardinella maderensis (Lowe, 1838) in the coastal waters of Ghana

Growth aspect of squid (Loligo chinensis) from the Banyuasin Coastal Waters, South Sumatra, Indonesia

Population Dynamics of Bigeye Grunt, Brachydeuterus auritus (Valenciennes, 1831) in Ghana and Management Implications

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