Feeding habits of the freshwater crab Sodhiana iranica from Southern Iran

Abstract

Aim: Freshwater crab, Sodhiana iranica, is an endemic gecarcinucid crab that has been recently reported from Southern Iran. This research examined some feeding aspects of S. iranica from Eelood freshwater spring, Southern Iran. Methods: Crabs were randomly sampled from April 2012 to April 2013, on a bimonthly basis. The stomach contents were obtained from 120 exemplars with carapace width ranging from 15.0 to 35.2mm. Results: Results showed stomach contents consist of mainly large quantities of plant remains, insects, oligochaetes, crustaceans and also small quantities of unidentifiable matter and debris. Major food groups were observed in different season, with plant remains the most dominant in spring (39.8%), whereas in autumn, the insects and crustaceans were dominant with 38.6% and 23.1%, respectively. The other food items include oligochaetes and debris, were the most abundant in summer (19.0%) and winter (15.5%), respectively. There were no difference observed in the quantity of the food consumed in both sexes and also significant differences observed in the preference for food items in the different season. The CV index varied significantly in both sexes that were ranged between 1.4 to 38.9% and 12.5 to 83.3%, for male and female, respectively. Conclusions: Despite the diversity in diets and feeding habits of S. iranica, it was shown an herbivore-biased omnivore mainly rely on plant sources.Keywords: crab; Decapoda; CV index; feeding; freshwater.Resumo: Objetivo: o caranguejo de água doce, Sodhiana iranica, é uma espécie endêmica da família Gecarcinucidae que recentemente foi registrado no sul do Irã. Esta pesquisa examinou alguns aspectos de alimentação de S. iranica de uma nascente de água doce da região de Eelood, no sul do Irã. Métodos: os caranguejos foram amostrados aleatoriamente de abril de 2012 a abril de 2013, em intervalos de dois meses. O conteúdo estomacal foi obtido a partir de 120 exemplares com largura de carapaça variando de 15,0 a 35,2 mm. Resultados: os resultados mostraram que os conteúdos estomacais consistiram principalmente de grandes quantidades de restos vegetais, insetos, oligoquetas, crustáceos e também pequena quantidade de materiais não identificados e detritos. Os principais itens alimentares foram observados em diferentes épocas, sendo restos vegetais os dominantes na primavera (39,8%), enquanto que no outono, os insetos e os crustáceos foram dominantes com 38,6% e 23,1%, respectivamente. Os oligoquetas e detritos foram mais abundantes no verão (19,0%) e no inverno (15,5%), respectivamente. Não se observou diferenças na quantidade de alimentos consumidos entre os sexos, mas diferenças significativas dos itens alimentares nas diferentes estações do ano. O índice CV variou significativamente para ambos os sexos, entre 1,4 a 38,9% e 12,5 a 83,3%, para machos e fêmeas, respectivamente. Conclusões: a despeito da diversidade das dietas e dos hábitos alimentares de S. iranica, esta espécie apresentou uma dieta onívora com tendência à herbivoria dependente principalmente ...

Natural Diet of Two Commercial Crab Species, <i>Portunus segnis</i> (Forskål, 1775) and <i>P. sanguinolentus</i> (Herbst, 1783), in the Coastal Waters of Karachi

“…The analysis of stomach contents usually involves a quantitative and qualitative determination of the kinds and amounts of food consumed. There are several methods of analyzing and presenting the data of stomach contents (see [8,17,18]), but in case of crabs usually the occurrence method and point method are used [22]). In occurrence method the number of crab in which each food item occurs is recorded and expressed as a percentage of total number of crab examined.…”