Non-commercial fish species in by-catch composition of shrimp trawl landing from Mahshahr creeks

Non-commercial fish species of shrimp trawls were studied monthly from October 2005 to September 2006 in Mahshahr creeks (Darvish, Doragh, Bihad, Ghazaleh, Ghanam, Zangi and Patil). The trawl nets had a cod-end mesh size of 24mm. Total catch was 6431 individuals weighing 55.5kg, and included 14 species of non-commercial fish species belonging to 14 families. The caught shrimp species were from Penaeidae; comprising only 30% of the total catches (4506 individuals weighting 44kg). Dominant species were Lieognathus hindus (54.8%), Metapenaeus affinis (18.2%) and Parapenaeopsis stylifera (9.8%). Maximum fish abundance was observed in March 2005 (98/3%) and for shrimp in June (66.2%). Bihad creek had the maximum percentage of fish (91.8%) by-catch and shrimp (42.9%) abundance. We conclude that the by-catch percentage of non-commercial fish is higher than shrimps in the study areas. Warm months witnessed the highest abundance of shrimp while January-March was the time period when by-catch was most abundant

Study of morphological characteristics and frequency of Dendrobranchiata larval shrimp in artificial reefs of Khuzestan coasts, Bahrekan area

This study was done to identify larval stages and biodiversity of Dendrobranchiata planktonic communites in artificial reefs of Khuzestan coasts(Bahrekan area in Northwest Persian gulf) for one year from May 2011 to April 2012 monthly basis. Sampling was conducted using a plankton net with a spring 300 micrometers. Totally, from two superfamily: Penaeoidea and Sergestoidea, 3 families: Sergestidae, Luciferidae, Penaeidae were identified.From Penaeidae family, Metapenaeus affinis ,Penaeus indicus and Parapenaeopsis stylifera species, from Luciferidae family, Lucifer hanseni specie and from Sergestidae family, Acetes sp specie were identified and introduced. Also larval density of identified species in different months and stations are calculated and determined Metapenaeus affinis specie (With the average of number per cubic meter in 1029±830) from Penaeidae family account for larval density is maximum in September. Finally, two abundance peak was observed that the first peak was in September and the second peak was in November. The maximum of relative frequency percentage in Penaeoidea superfamily related to mysisI stage and 62 percentage. The results obtained indicate that the artificial structures are well managed nursery area for Penaeidae shrimp. The maximum average value of Shanon-wiener index was in November (1.36) due to the presence of all species in the same month. Simpson index was lowest in November, which confirms the above conclusion