Herbivory and seasonal changes in diet of a highly endemic cyprinodontid fish (Aphanius farsicus)

Abstract

Trophic ecology is essential to understand ecosystem functioning and structure and assist biological conservation. Here we investigate, for the first time, the feeding ecology of Aphanius farsicus, a cyprinodontid fish endemic of a single landlocked river basin in central Iran. We sampled monthly a population of this fish species during a year and examined differences in food across seasons, sexes and sizes. Similarly to other cyprinodonts, A. farsicus showed sexual dimorphism and more abundance of females. Size structure and individual condition varied across seasons, with larger fish in spring and better condition in summer and less in winter. We found no empty guts, suggesting that these fish feed all year round due to the warm climate of its native distribution. Farsi toothcarp diet was based on detritus, algae (particularly diatoms, green algae, and cyanobacteria), and small invertebrates. Seasonal variation in diet was more important than variation due to fish size and the Farsi toothcarp consumed more green algae in spring and early summer and more diatoms and insects the rest of the year. Herbivory was considerable, similarly to a few other cyprinodonts, and increased with fish size, particularly because of higher consumption of green algae. As with species composition in diet, season was more important than size in the variation of number, biovolume, mean size, and diversity of prey captured, with higher number, richness and size of prey captured in summer. The ontogenetic diet shift was less marked in this cyprinodont than in many other Aphanius species, probably due to its reduced size and the resource availability of its habitat, but was also shown by size-dependent feeding selectivity for a few invertebratesFinancial support was provided by the Deutscher Akademischer Austauschdienst (DAAD) through a doctoral fellowship to ZG and by the Spanish Ministry of Science (projects CGL2009-12877-C02-01 and Consolider-Ingenio 2010 CSD2009-00065

Seasonal and depth variations in diet composition and dietary overlap between three native killifish of an emblematic tropical-mountain lake: Lake Titicaca (Bolivia)

“…According to Monroy et al, (2014), O. agassizii is an omnivorous species, and like other Cyprinodontiform species (Kalogianni et al , 2010; Alcaraz et al , 2015) it is not possible to generalize the feeding pattern for this species throughout the lake without considering other influencing factors (Saikia, 2016; Yoğurtçuoğlu et al , 2018). A clear influence of seasonality and depth was observed in the results, which has influenced by feeding habits changing the proportions and importance of the prey (Table 4).…”

Diversity and structure of fragmented populations of a threatened endemic cyprinodontid (Aphanius sophiae) inferred from genetics and otolith morphology: Implications for conservation and management

“…In addition to p values, we used η 2 (eta squared) as a measure of effect size (i.e., importance of factors). Similarly to the regression coefficient ( r 2 ), η 2 is the proportion of variation explained for a certain effect (see Alcaraz, Gholami, Esmaeli, & García‐Berthou, ; Alcaraz, Pou‐Rovira, & García‐Berthou, for more details). Stepwise forward canonical discriminant analysis (CDA) was performed considering otolith morphometric variables and fish standard length in order to find linear combinations of the variables that best summarized differences among fish populations.…”

Application of machine vision systems in aquaculture with emphasis on fish: state‐of‐the‐art and key issues

“…Besides, farmers can use the fish species identification for feeding strategies (Gerking ; Alcaraz et al . ) and stock assessment (Hoggarth ). Fish species identification also can be used to have more accurate fish disease diagnosis.…”

“…Farmers need to sort harvested fish according to species and size for better marketing in polyculture fish farming system. Besides, farmers can use the fish species identification for feeding strategies (Gerking 1994;Alcaraz et al 2015) and stock assessment (Hoggarth 2006). Fish species identification also can be used to have more accurate fish disease diagnosis.…”