The family Ariidae, sea catfish of the order Siluriformes, is widely distributed throughout the world, particularly in tropical and subtropical areas The three species of Ariidae found on the coasts and estuaries of West Africa are the smoothmouth catfish Carlarius heudelotii (Valenciennes 1840), the rough-head catfish Carlarius latiscutatus (Gunther 1864) and the Guinean sea catfish Carlarius parkii (Gunther 1864) They have been increasingly exploited by artisanal and industrial coastal fisheries in recent decades, but there is still little information available on their ecology and biology The aim of this study was to deepen our knowledge of these three West African Ariidae species based on a dataset collected between 1980 and 2013 during experimental fishing programmes They were carried out in Mauritania in the Banc d'Arguin National Park, in Senegal in the Sine Saloum estuary including the Bamboung Marine Protected Area (MPA), in The Gambia in the Gambia estuary, in Guinea-Bissau in the Urok Islands MPA in the Bijagos archipelago, in Guinea in the Fatala estuary and Dangara inlet, and in Cote d'Ivoire in the Ebrie Lagoon C latiscutatus accounted for 65%, C parkii for 29% and C heudelotii for 6% of total number of Ariidae sampled C latiscutatus was abundant in the Sine Saloum and Gambia estuaries as well as in Guinea and Guinea-Bissau and was the only species present in the Ebrie Lagoon C parkii was in the majority in Mauritania The three species were recorded in a salinity range of 0 to 50, a temperature range of 19 to 34°C, in areas 17 to 15 m depth, and transparency ranging from 01 to 4 m (Secchi disk depth) C heudelotii was present in less saline (25 vs 32-34), less warm (27 vs 29°C) and less transparent (08 m vs 16 m) waters than the two other species The maximum sizes (453 mm, 614 mm and 525 mm for, respectively, C heudelotii, C latiscutatus and C parkii) were comparable to those recorded at sea Length-weight relationships calculated for each species showed b coefficients greater than 3 Sex ratios were always in favour of females The number of mature individuals and their smallest size at maturity were calculated per species, sex and study area A size of 27-28 cm at first maturity was estimated for females of C latiscutatus A few dozen records made it possible to describe fecundity and cases of oral incubation by females The diet of the three species was composed of crustaceans, fish and molluscs, confirming their classification as generalist predators Thanks to their high environmental tolerance, these sea catfish populations are able to occupy both the continental shelf and adjacent estuaries throughout their life cycle, with the exception of spawning, which generally takes place at sea

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Biology and ecology of sea catfish (Ariidae) of estuarine, lagoon and coastal ecosystems in West Africa.

Marine fish stocks are increasingly being exploited to unsustainable levels. Yet, knowledge of basic biological and ecological traits of species, required to sustain fisheries management at a local...

Reproductive ecology and growth of marine catfishes (Ariidae) supporting sustainable fisheries in Banc d’Arguin National Park, Mauritania

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 R 2 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) 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.

Biometric indices and population parameters of three polynemid fishes from Batang Lassa Estuary of East Malaysia.

This work describes the results of some esperiments carried out on the effect of the temperature, the photoperiod, the spawners food regime and other biotic factors upon the captive brood stock of Sea Bass (Dicentrarchus labrax), Turbot (Scophtalmus maximus), Sole (Solea solea), Gilthead Sea Bream (Sparus aurata and Red Mullet (Mullus surmuletus). The results clearly show that ail the above species spawn naturally in captivity conditions. A number of spawns can be obtained in tanks where only one species or a pool of species is maintained under natural or artificial temperature and photoperiod, with fish receiving different types of food diet and in tanks of varying capacity. The characteristics of each spawn varies according to the following factors : - The spawning season : it can be either naturally or artificially induced through the photoperiod and temperature pattern input in the tanks. - The total number of eggs per spawn : it is related to both the female physiological condition and the spawners' environmental parameters such as temperature and photoperiod. - The egg size and viability : the temperature seems to determine the egg diameter,and the overall egg viability seems to be related to the diet and to the capacity of the tanks. Nevertheless, no clear relation was found between the egg hatching rate and the environmental and physiological conditions of the spawners.

Etude de l'influence de facteurs internes et externes sur la reproduction de poissons marins en captivité

Some Aspects of the Growth Features and Condition Factor of (Boulenger, 1911) from Obuama Creek (Rivers State, Nigeria)

Background and Objectives: Marine catfish are abundant in the bays of Tabounsou and Sangareah in Republic of Guinea, but the knowledge on their biology is still scanty. The reproductive biology of Arius latiscutatus Günther, 1864 and A. gigas Boulenger, 1911 was studied through monthly sampling, from January to December 2016. Methodology: Fish were caught using gill nets in several sampling sites. Five gonadal stages were described, based on macroscopic observation of gonad form, size, weight, color and oocyte diameter. Original Research Article Koivogui et al.; ARRB, 35(8): 1-13, 2020; Article no.ARRB.59185 2 Results: The population was dominated by males (61%) in A. latiscutatus and females (53%) in A. gigas, showing a sex-ratio of 1:1.54 (Chi-square, P < 0.05) and 1:0.88 (P > 0.05), respectively. The length-weight relationship was a positive allometry for A. latiscutatus and A. gigas, and males (35.37 and 35.47 cm, respectively) reached first maturity earlier than females (39.7 and 40.8 cm, respectively). Changes in the gonadosomatic index (GSI) and in stages of gonadal development showed that A. latiscutatus spawned between April and October, while A. gigas spawned in May to November. The peak of condition factor was observed in June (0.68±0.05) and July (0.55±0.04) in females of A. latiscutatus and A. gigas, respectively. Conclusion: Both species, having only one annual breeding season, A. latiscutatus spawns earlier than A. gigas. Coastal fisheries should be restricted in cold season to preserve the ability of broodstock renewal for these species.

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Reproductive Biology of Marine Catfish, Arius latiscutatus (Günther, 1864) and Arius gigas (Boulenger, 1911) from the Bays of Guinea

The study evaluated some population parameters of Polydactylus quadrifilis within Ebrié lagoon (Potou sector). Samples were obtained using artisanal gillnet fishery from April 2004 to March 2006. A total of 741 individuals of P. quadrifilis ranged from 11 to 70 cm were examined. Population parameters were estimated where asymptotic length (L∞) was found 60 cm, growth rate (K) 0.33 per year, the longevity (T max) 9.09 years, and growth performance index (Φ′) 3.06. The length at first capture (Lc50 = 10.60 cm) was lower than the length at first maturity (Lm50 = 40 cm). Total mortality rate (Z) was calculated as 1.10 per year including natural mortality and fishing mortality. The exploitation rate (E=0.36) was found to be less than the maximum exploitation rate (E max = 0.44) and indicated that P. quadrifilis is not overexploited. The current exploitation rate should be maintained by sustainable fisheries measures including monitoring of fishing effort. Original Research Article Bédia et al.; AJFAR, 9(2): 33-42, 2020; Article no.AJFAR.60803 34

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Growth Pattern, Mortality and Exploitation Rate of the Giant African Threadfin, Polydactylus quadrifilis (Cuvier, 1829) from Ebrié Lagoon (Potou Sector, Côte d’Ivoire)

Bakari Coulibaly

Papers

Reproductive Biology of Marine Catfish, Arius latiscutatus (Günther, 1864) and Arius gigas (Boulenger, 1911) from the Bays of Guinea

Growth Pattern, Mortality and Exploitation Rate of the Giant African Threadfin, Polydactylus quadrifilis (Cuvier, 1829) from Ebrié Lagoon (Potou Sector, Côte d’Ivoire)