Abundance and Reproductive Biology of the Penaeid Prawns of Bagamoyo Coastal Waters, Tanzania

Teikwa, ED; Mgaya, YD

doi:10.4314/wiojms.v2i2.28441

Cited by 4 publications

(6 citation statements)

References 13 publications

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“…The high pecentages of crabs and shrimps was moslty observed from fish samples caught between December and July, probably due to an increase in abundance after spawning, which is reported to occur between late October to November (Svane and Hooper, 2004). In addition it has been reported that the onset of the wet season (March to May) triggers an offshore migration of juvenile shrimps (Teikwa and Mgaya, 2003). Bivalves were found mostly in the diet of invertivore-piscivore fishes caught in the sandy area, possibly due to the preference of bivalves to such habitats.…”

Section: Discussionmentioning

confidence: 99%

The trophic structure of fish in seaweed farms, and adjacent seagrass and coral habitats in Zanzibar, Tanzania

Yahya

Mmochi

et al. 2021

West Ind. Oc. J Mar. Sci.

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Coral reefs, seagrasses and seaweed farms (Eucheuma denticulatum) are characteristic habitats in many parts of the coast of Zanzibar, Tanzania. However, information on trophic interactions, movements of fish, and variation in fish diet specialization between these habitats are scarce. The present study determined the trophic structure and the variation in diet composition of fish caught in (floating) seaweed farms, and in adjacent seagrass and coral reef habitats in Pongwe, Zanzibar. Fish were caught using traditional basket traps (dema) and gut contents of 392 fish were analyzed. A one-way Analysis of Similarities (ANOSIM) showed that there was a significant difference in the composition of prey items eaten by invertivores in different habitats (Global R = 0.109, p = 0.002.). There was no significant difference in the composition of prey items eaten by herbivores, invertivore-piscivores and omnivores (p > 0.05), likely due to movement of fish between these habitats for foraging. There was no significant difference in the relative proportion of trophic groups between the habitats (p > 0.05) except for herbivores (p < 0.05). Floating seaweed farms attract invertebrates and smaller fish, thus providing feeding grounds for predatory fish, and should be considered as ecologically important habitats as are coral reefs and seagrass beds.

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Section: Discussionmentioning

confidence: 99%

The trophic structure of fish in seaweed farms, and adjacent seagrass and coral habitats in Zanzibar, Tanzania

Yahya

Mmochi

et al. 2021

West Ind. Oc. J Mar. Sci.

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“…Since prawns have a high fecundity rate, between 40 000 to 320 000 eggs (Teikwa and Mgaya, 2003), after a short period of closure, it could have been expected that the population of prawns would bounce back; however, the recovery took a decade (i.e., from 2007 to 2017) (Mwakosya et al, 2010;TAFIRI, 2021). Assessing other factors that might have been at play or contributed to prawn collapse and possibly a delayed recovery is vital.…”

Section: Introductionmentioning

confidence: 99%

River discharge, fishing effort and catch composition of prawn fisheries in coastal Tanzania

Silas,

Mgeleka,

Kangwe

2023

WIO J. Mar. Sci.

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This study examined the relationships between river discharge, fishing effort and catch composition of prawn fisheries in coastal Tanzania. Key assumptions were that river discharge would be a good indicator of rainfall and that the number of fishing vessels would reflect fishing intensity. We investigated whether reduced river discharge or increased fishing effort caused the collapse of the industrial prawn fishery in 2007, and which of these factors delayed recovery prior to reopening the fishery in 2017. The analysis showed a positive relationship between Catch Per Unit Effort (CPUE) and river discharge, with decreased river flow resulting in reduced prawn catches. The number of fishing vessels had little impact on CPUE before 2003, but thereafter CPUE declined even when fishing effort was reduced by 50%. A shift in trawl catches from a prawn-dominated fishery to a fish-dominated fishery was observed four years before the collapse. The trend in river discharge persisted below average (22 m³/s) between 2000 and 2007. Forewarning of low river discharge, changing trawl catch composition, and increasing effort may have led to developing proactive strategies to minimise the impact of a changing regime on fish stocks and dependent communities. We recommend establishing a monitoring system to anticipate similar events in the future.

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“…In Tanzania, prawns spawning is mainly seasonal (Bwathondi et al, 2002) and migrate to the open sea during the rainy season, usually from October to December (Silas, 2011). The spawning peak of prawns occurs in January to March and the new recruited ones appear in the coastal waters from February to May (Teikwa & Mgaya, 2003). Large population of juvenile prawns are recruited to the fishable of lower salinity areas in estuaries (Teikwa & Mgaya, 2003).…”

Section: Life Cycle Of Prawnsmentioning

confidence: 99%

“…The spawning peak of prawns occurs in January to March and the new recruited ones appear in the coastal waters from February to May (Teikwa & Mgaya, 2003). Large population of juvenile prawns are recruited to the fishable of lower salinity areas in estuaries (Teikwa & Mgaya, 2003). Pre-adults and adults are usually found in large numbers along the coast during the heavy rain season between March and May (Teikwa & Mgaya, 2003).…”

Section: Life Cycle Of Prawnsmentioning

confidence: 99%

“…Large population of juvenile prawns are recruited to the fishable of lower salinity areas in estuaries (Teikwa & Mgaya, 2003). Pre-adults and adults are usually found in large numbers along the coast during the heavy rain season between March and May (Teikwa & Mgaya, 2003). However, the Indian Ocean has high biodiversity hotspot of marine fauna and flora species including corals, mangroves, sea grasses, fishes, marine mammals, turtles, crustaceans and mollusks (Keesing & Irvine, 2005).…”

Section: Life Cycle Of Prawnsmentioning

confidence: 99%

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Heavy metals and pesticide residues as quality determinants for sustainable management of prawns along the Indian coastline of Tanzania

Patiri¹

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The presence of heavy metals and pesticide residues in prawns, water and sediments, were determine. Prawns, sediments and water samples were collected along prawns fishing zones in the Indian coastline of Tanzania. Zinc (Zn), lead (Pb) and cadmium (Cd) were analyzed using Atomic Absorption Spectrophotometry (AAS). Direct Mercury Analyzer (DMA) was used for mercury (Hg) analysis. Pesticide residues were analyzed by Gas ChromatographyMass Spectrophotometry (GC-MS). Information on stakeholder’s perception on the sources of aquatic pollution was collected using a structured questionnaire. Results indicated that, fertilizer (60.7%), pesticides (59.8%) and herbicides (60.7%) were the main sources of aquatic pollution. Cyberdip and Utupa-mixed local herbs were the chemicals used in prawns fishing. Heavy metal contaminants were predominant in sediments followed by prawns, and water. The heavy metals were highly concentrated in prawns and sediments in the order of Zn > Pb > Cd > Hg, and Pb > Zn > Cd > Hg in water respectively. Lambda-cyhalothrin was the only pesticide residue detected in prawns and sediments but not in water. Lambdacyhalothrin levels detected in prawns from Kisiju and Kilwa were 5.6 – 45.2 folds above the maximum acceptable limits. Lambda-cyhalothrin levels in sediments was 175; 4070 and 4432 folds higher than the maximum acceptable level in Bagamoyo, Kilwa and Kisiju respectively. Presence of Zn, Pb and lambda-cyhalothrin beyond acceptable limits in prawns and sediments may indicate marine pollution. The maximum acceptable level of lambdacyhalothrin in sediments is 0.00372 mg/kg and the maximum acceptable level of lambdacyhalothrin for prawns is 0.05 mg/kg. These pollutants may impair quality and safety of prawns and by-products which is a risk to the public health. Therefore, monitoring of agricultural and the anthropogenic activities around prawn fishing areas is inevitable.

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Abundance and Reproductive Biology of the Penaeid Prawns of Bagamoyo Coastal Waters, Tanzania

Cited by 4 publications

References 13 publications

The trophic structure of fish in seaweed farms, and adjacent seagrass and coral habitats in Zanzibar, Tanzania

The trophic structure of fish in seaweed farms, and adjacent seagrass and coral habitats in Zanzibar, Tanzania

River discharge, fishing effort and catch composition of prawn fisheries in coastal Tanzania

Heavy metals and pesticide residues as quality determinants for sustainable management of prawns along the Indian coastline of Tanzania

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