The influence of seagrass type on the distribution and abundance of postlarval and juvenile tiger prawns (Penaeus esculentus and P. semisulcatus) in the western Gulf of Carpentaria, Australia
Loneragan, N.R., Kenyon, R.A., Staples, D.J., Poiner, I.R. and Conacher, C.A. (1998) The influence of seagrass type on the distribution and abundance of postlarval and juvenile tiger prawns (Penaeus esculentus and P. semisulcatus) in the western Gulf of Carpentaria, Australia. Journal of Experimental Marine Biology and Ecology, 228 (2). pp. 175-195.
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Postlarval and juvenile tiger prawns (Penaeus esculentus and P. semisulcatus) were sampled by beam trawls in different seagrass communities of the western Gulf of Carpentaria to test the influence of seagrass characteristics on their distribution and abundance. Two sampling regimes were carried out: fortnightly sampling over a 3 month period during the time of peak recruitment to investigate the importance of different seagrass types to tiger prawns; and at one time to investigate the wider geographic patterns of distribution and abundance of tiger prawns. The results from both studies showed that the pattern of distribution and abundance of 1–1.9 mm carapace length (CL) postlarvae differed from those for the 2–2.9 mm CL postlarvae and juvenile tiger prawns (≥3 mm CL). The 1–1.9 mm CL size class consists of individuals that are about to settle and those that have recently settled: this size class was more widely distributed than the larger postlarvae and juveniles and was sometimes found on substrates where no seagrass was present. Larger tiger prawns were found in higher numbers on seagrass beds where the tall, broad-leaved seagrass Enhalus acoroides was the dominant species. Although seagrass biomass was not a consistent linear predictor of juvenile tiger prawn numbers, mean catches of both the 2–2.9 mm CL postlarvae and juvenile P. esculentus were highest when the biomass of seagrass exceeded 100 g m−2. However, these high biomass seagrass beds contribute only 6% to the total extent of seagrasses in the shallow waters (<2.5 m deep) of the Gulf of Carpentaria. Although the numbers of juvenile tiger prawns were lower in the low-biomass seagrass beds, because of their extent, these seagrass beds are the main nurseries for sustaining the production of the valuable Northern Prawn Fishery in Australia.
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|Copyright:||© 1998 Elsevier Science B.V.|
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