Maturity, fecundity, and breeding seasons of the major catfishes (suborder: siluroidea) in Lake Victoria, East Africa

Rinne, John N.; Wanjala, B.

doi:10.1111/j.1095-8649.1983.tb02915.x

Cited by 21 publications

(18 citation statements)

References 8 publications

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“…These factors include evolutionary history, availability of nursery areas (Rinne & Wanjala, 1983), interspecific competition for food among juveniles, species social system (Kramer, 1978), and habitat stability (Humphries et al, 1999). For explaining the reproductive pattern of C. guanes we lean towards the hypothesis that a more stable habitat (no flash floods) during dry seasons (Humphries et al, 1999) could favor the survival of offspring and female recovery.…”

Section: Discussionmentioning

confidence: 99%

“…Most tropical freshwater fish breed during the rainy season (Kramer, 1978;Munro, 1990;Vazzoler & Menezes, 1992;Jiménez-Badillo & Nepita-Villanueva, 2000;Alkins-Koo, 2000); however, a few breed during the dry season (Kramer, 1978;Wang et al, 1995;Pusey et al, 2002;Torres-Mejia & Ramírez-Pinilla, 2008), or throughout the year (Kramer, 1978;Alkins-Koo, 2000). Interspecific variation in reproductive seasonality has been associated with several factors, such as availability of nursery areas (Rinne & Wanjala, 1983), availability of food for adults or juveniles (Lake, 1967;Kramer, 1978), competition for breeding sites, and phylogenetic inertia (Kramer, 1978). In this study we explored the hypothesis that in tropical freshwater fish the hydrological cycle indirectly affects reproductive seasonality through diet.…”

Section: Introductionmentioning

confidence: 99%

“…It has been shown that many fish totally or partially shift their diets across seasons (Prejs & Prejs, 1987;Mazzoni & Rezende, 2003), and the highest feeding activity usually occurs during the rainy seasons when the availability of prey is relatively higher (Prejs & Prejs, 1987). Many tropical freshwater fish reproduce during or after peak food availability and consumption (Rinne & Wanjala, 1983;Esteves & PintoLobo, 2001;de Alvarenga et al, 2006). Others can diminish or even cease food ingestion during the reproductive season (Ikomi, 1996;Santamaría-Miranda et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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How does diet influence the reproductive seasonality of tropical freshwater fish?: A case study of a characin in a tropical mountain river

2009

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Seasonal breeding of tropical freshwater fish may be synchronized with periods of high food consumption. We explored this hypothesis by studying the relationship between diet and reproductive activity of Creagrutus guanes (Teleostei, Characidae). Our results showed that C. guanes had a generalist and omnivorous diet dominated by aquatic insects (mainly Diptera larvae) and seeds. Creagrutus guanes did not show intersexual or ontogenetic variation in diet. Peaks of feeding activity during rainy months were not synchronized with breeding in dry months. Our results do not support the hypothesis that the reproductive season has to be synchronized with high food consumption. We discussed the hypothesis fat reserves may be an important factor for the desynchronization of peaks of feeding and reproduction as explanation of seasonal breeding of this species.A reprodução sazonal de peixes tropicais de água doce pode estar sincronizada com períodos de alto consumo de alimento. Nós examinamos esta hipótese estudando a relação entre dieta e atividade reprodutiva de Creagrutus guanes (Teleostei, Characidae). Nossos resultados mostraram que C. guanes teve uma dieta generalista e onívora, com predominância de insetos aquáticos (principalmente larva de Diptera) e sementes. Creagrutus guanes não apresentou variação intersexual ou ontogenética na dieta. Picos de atividade alimentar durante os meses chuvosos não foram sincronizados com atividade reprodutiva nos meses secos. Nossos resultados não sustentam a hipótese de que a estação reprodutiva está sincronizada com o consumo elevado de alimento. A reserva de gordura pode ser um fator importante para a dessincronização de picos de alimentação e reprodução (a reserva de gordura pode influenciar a ausência de sincronia entre os picos de alimentação e reprodução). São apresentadas hipóteses alternativas para a explicação de desova sazonal da espécie.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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How does diet influence the reproductive seasonality of tropical freshwater fish?: A case study of a characin in a tropical mountain river

2009

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“…Based on a length-weight relationship established by Clay and Clay (1981), the average Clarias should have weighed between 1.2 and 2 kg. Rinne and Wanjala (1983) note that C. gariepinus matures at an estimated TL of approximately 50 cm, suggesting that most Clarias individuals at Wadh Lang'o should be mature adults.…”

Section: Fish Size Estimatesmentioning

confidence: 98%

Kansyore fisher-foragers and transitions to food production in East Africa: the view from Wadh Lang'o, Nyanza Province, Western Kenya

Prendergast

2010

Azania: Archaeological Research in Africa

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The site of Wadh Lang'o in southern Nyanza Province (Kenya) has produced a very large faunal assemblage in association with Kansyore, Elmenteitan and Urewe ceramics. The stratigraphy of the site appears to be intact and six dates have been obtained from the sequence, making this the best opportunity to look at diachronic change in subsistence strategies in this region. The main results of the zooarchaeological analysis are presented here, with emphasis on the Kansyore component. Two important findings are discussed: first, the fish remains, when taken together with remains from other Kansyore sites and considering the behavioural traits of these fish, suggest that Kansyore riverside and lakeshore sites were occupied in distinct seasons and used together in a single settlement and subsistence system. Second, the mammalian remains suggest that while Kansyore foragers hunted a broad range of taxa, they also began to consume domesticates perhaps as early as the mid-to late-third millennium cal. BC. This suggests that occupants of late Kansyore sites were in contact with food producers, but whether the domestic animal remains are the result of exchange, or of adopting food production, remains ambiguous.Le site de Wadh Lang'o, au sud de la province de Nyanza (Kenya), a produit un grand ensemble faunistique en association avec poterie du style Kansyore, Elmenteitan et Urewe. La stratigraphie du site semble entière et six datations ont permis de dater la séquence, en rendant ce site fondamental pour l?étude du changement diachronique des stratégies de subsistance de la région. Les principaux résultats de l?analyse zooarchéologique sont présentés ici, avec un accent sur le composant Kansyore. Deux découvertes sont discutées: la première est l?étude du poisson. Les restes du poisson quand sont considérés en conjonction avec d?autres sites de type Kansyore, suggère que les sites près du lac et ceux formés prés des rivières ont été occupés dans des saisons différentes et ont été parties d'un système saisonnier de subsistance et d'installation. La seconde découverte, d?après l?étude des restes des macro-mammifères, suggère que bien que les populations du Kansyore aient chassé une gamme très grande de taxons sauvages, ils consommaient aussi des animaux domestiqués au milieu ou fin du troisième millénaire av. J.-C. Ceci indique que les occupants des sites appartenant à la phase finale du Kansyore étaient en contact avec des producteurs. La manière auquel ces populations obtenaient ces animaux (échange, élevage) reste encore ambiguë.*

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“…Various workers have studied reproductive biology of B. docmak in some African water bodies (McKaye and Oliver, 1980;Rinne and Wanjala, 1983;Dadzie and Okach, 1989). The available information indicates that B. docmak moves to shallower water to spawn where it makes a nest on sandy bottom against rocks.…”

Section: Introductionmentioning

confidence: 99%

Reproductive biology and condition factor of the catfish Bagrus docmak (Forsskål) (Pisces: Bagridae) in Lake Chamo, Ethiopia

Anja

Dadebo

Mengistou

2011

SEJS

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Some aspects of reproductive biology, length-weight relationship and condition factor of 534 (258 males and 276 females) Bagrus docmak (Forsskål) in Lake Chamo were studied from samples taken during February 1995 to February 1996. B. docmak had an extended breeding period from February to August, with peak spawning in May for both sexes, when 76.2% males and 78.3% females had ripe gonads. The main pulse in breeding activity occurred during the rainy months of April and May. The overall sex ratio (male: female) was 1:1.07 which did not deviate significantly from the hypothetical distribution of 1:1 (x 2 =0.61, p>0.05). However, sex ratio was significantly different from 1:1 in the samples >90 cm fork length (FL) (x 2 = 10.71, p<0.001). Size (FL) of first maturity was 62.0 cm for males and 69.0 cm for females. The mean number of eggs per female was 276,500. Ripe ovaries contained 990-2,100 eggs per gram of preserved wet weight with a mean number of 1,475. Fecundity was positively related to FL (r 2 = 0.75, p<0.05), total weight (TW) (r 2 = 0.73, p<0.05) and ovary weight (OW) (r 2 = 0.90, p<0.05). Length-weight relationship of B. docmak is best expressed by the equation TW= 0.0054FL 3.24 . Monthly Clark's condition factor (mean +/-SE) ranged from 0.426± 0.011 to 0.489± 0.014 for males and from 0.449± 0.010 to 0.489± 0.012 for females.

show abstract

Maturity, fecundity, and breeding seasons of the major catfishes (suborder: siluroidea) in Lake Victoria, East Africa

Cited by 21 publications

References 8 publications

How does diet influence the reproductive seasonality of tropical freshwater fish?: A case study of a characin in a tropical mountain river

How does diet influence the reproductive seasonality of tropical freshwater fish?: A case study of a characin in a tropical mountain river

Kansyore fisher-foragers and transitions to food production in East Africa: the view from Wadh Lang'o, Nyanza Province, Western Kenya

Reproductive biology and condition factor of the catfish Bagrus docmak (Forsskål) (Pisces: Bagridae) in Lake Chamo, Ethiopia

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