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

Abstract

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.

Sombreiro Nehri'ndeki (Nijer Deltası, Nijerya) Sardinella maderensis'in (Lowe, 1838) Bazı Popülasyon Parametreleri

“…In this study the value of growth performance index of S. maderensis was found to be 2.46. The result is lower than values reported for the same species by Amponsah et al, (2018) in coastal waters of Ghana and by Marcus (1989) in coastal waters around Lagos, Nigeria. The difference in values could be due to poor state of water quality in the study area as a result oil pollution and other human activities in and around the Sombreiro River.…”

“…The length at which 75% fish are retained in the gear was estimated as 39.75 cm.. The values in the current study were higher than those recorded in the coastal waters of Ghana for S. maderensis L 25 %, L 50 % and L 75 % were 4.40 cm, 5.30 cm and 6.12 cm respectively by (Amponsah et al, 2018) In Senegal, the work performed by Boely (1980) and (Levenez 1993) showed that the L 50 in this area was 20 cm.…”

“…Age at zero length (t 0 ) stood at -0.03 year-¹. Amponsah et al (2018) reported the age at birth (t 0 ) for the same fish species at -0.284 year-¹ from coastal waters of Ghana. It has been reported that there must be some differences between growth characteristics among localities as a result of diversity and availability of dietary items, hydrographical and climatic conditions (Bartulovic et al, 2004).…”

Fishing of the Flat Sardinella (<i>Sardinella maderensis</i>, Pisces, Lowe 1838) in Benin (West Africa) Nearshore Waters: Production, Typology of Fishing Gear and Current Status of Its Stock

“…The total mortality Z in current study was higher than those reported by Sossoukpe et al (2016) [16] in Benin, Olopade et al (2019) [17] in Nigeria, Amponsah et al, (2019) [18] and Osei (2015) [19] on the Ghanaian coasts. The high estimate of Z in a study may indicate greater pressure on the species that may result from increasing one or both components (M and F) of Z (Olopade et al,…”

Parasites of Sardinella maderensis (Lowe, 1838) (Actinopterygii: Clupeidae) and Their Potential as Biological Tags for Stock Identification along the Coast of West Africa

“…Sardinella maderensis and S. aurita represent the most abundant and commercially important species of small marine pelagic fish along the coast of West Africa [ 2 ]. Together, they account for more than 40% and 16.2% of total landings in Ghana and Benin, respectively, with S. maderensis being the most abundant fish species in Benin [ 3 , 4 ]. The lack of reliable data on stock structure for the management of small pelagics in general, and these two Sardinella sp(p).…”