The biology and ecology of the rocky shore crab Leptodius exaratus (H. Milne Edwards, 1834) on the coast of Kuwait

Al-Wazzan, Zainab A. (2017) The biology and ecology of the rocky shore crab Leptodius exaratus (H. Milne Edwards, 1834) on the coast of Kuwait. PhD thesis, Prifysgol Bangor University.

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The rocky shore crab Leptodius exaratus is an important economic resource, as bait for recreational fishing in Kuwait. The biology and ecology of this species were investigated through a series of field studies and laboratory experiments carried out along the Kuwait coast between 2013-2015. These studies included population structure, spatial and temporal abundance, hatching, trophic ecology and the fishery. Demographic traits were quantified, including size at maturity, sexual dimorphism, fecundity, seasonal and spatial patterns of recruitment, growth, mortality and reproduction. The results show that growth and reproduction were seasonal, with high growth and spawning peaks between April-September. Abundance increased in summer and decreased in winter. Males, females and juveniles had similar spatial and seasonal distributions. Larval release patterns identified a nocturnal endogenous hatching rhythm with peaks being around neap tides. The results of the study on trophic ecology of L. exaratus and the coexisting crab species Pilumnopeus convexus indicate that adults of both species occupy a high trophic level in the rocky shore community, potentially influencing intertidal community structure and diversity. These species had distinct isotopic niches, reducing resource competition. The results of the fishery study indicates that L. exaratus represented 21.4% of the intertidal catch, with an average harvesting rate of 191 crabs/collector/tide. Fishing mortality was relatively low but habitat damage, caused by gleaning was high in sites with low crab abundance, in which 80% of the rocks were turned over and more than half broken. This indicates the need to protect intertidal habitats and to enforce control of gleaning practices. Such studies are very limited regionally and globally, making the results of the present study valuable in understand the biology of this crab species and its role in the rocky shore community and to inform development of action plans to protect intertidal habitats and control gleaning practices.

Item Type: Thesis (PhD)
Subjects: Degree Thesis
Departments: College of Natural Sciences > School of Ocean Sciences
Degree Thesis
Date Deposited: 07 Aug 2017 12:22
Last Modified: 07 Aug 2017 12:22
URI: http://e.bangor.ac.uk/id/eprint/10249
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