Feeding ecology of three sympatric species of stingrays on a tropical mudflat

Abstract

Periodic fish ingressions into intertidal areas during high tide are known to occur on tropical mudflats. This study aimed to elucidate the feeding ground function of coastal mudflats for three common stingray species in the Klang Strait, Malaysia. Stingrays (disc width range from 5.65–54.50 cm) sampled over 17 months using a large barrier net (~2 ha enclosure) at two sampling sites were examined for their diet composition, prey frequency and prey volume according to predator species and maturity. The index of relative importance and Schoener's index of diet overlap were calculated. The three stingray species fed on relatively similar prey items which varied in size and contribution. Brevitrygon heterura fed on the widest range of prey taxa (28) whereas Hemitrygon bennetti (22) and Telatrygon biasa (17) showed higher prey specialization. The Penaeidae (dominantly Metapenaeus brevicornis and M. affinis) were the most important food item in the stingray diet which also included Actinopterygii, Amphipoda, Brachyura and Calanoida. The stingray diet showed an ontogenetic shift, with young stingrays tending to be generalists whereas the more mature stingrays (except H. bennetti) become more specialized in their feeding habits. This shift in feeding strategy reflects the diversity of prey taxa abundantly available to young stingrays on the mudflats, while the larger stingrays adapt to feed on larger prey once they enter deeper waters.

Growth, maturity, and diet of the pearl whipray (Fontitrygon margaritella) from the Bijagós Archipelago, Guinea-Bissau

“…This indicates that F. margaritella acts as a small, low trophic level meso-predator that links benthos communities with top-predators in the Bijagós Archipelago. The presence of teleost items the stomach contents of F. margaritella suggests that the species occasionally consumes teleost prey, as observed in other batoid species ( Lim et al, 2019 ; Farias et al, 2006 ). Whereas other studies show that batoids ontogenetically include more teleost prey ( Gray, Mulligan & Hannah, 1997 ; Lim et al, 2019 ; Farias et al, 2006 ), in our study one YOY was observed to have consumed small teleost prey.…”

“…The presence of teleost items the stomach contents of F. margaritella suggests that the species occasionally consumes teleost prey, as observed in other batoid species ( Lim et al, 2019 ; Farias et al, 2006 ). Whereas other studies show that batoids ontogenetically include more teleost prey ( Gray, Mulligan & Hannah, 1997 ; Lim et al, 2019 ; Farias et al, 2006 ), in our study one YOY was observed to have consumed small teleost prey. The high proportion of unidentified prey encountered likely results from soft-bodied prey ( e.g ., polychaetes and small crustaceans) which may digest faster ( Farias et al, 2006 ).…”

“…We found that F. margaritella undergoes an ontogenetic diet shift and adults seem to incorporate more diverse prey into their diet such as teleosts and a higher abundance of crustaceans, possibly giving older individuals a slightly higher trophic level. Ontogenetic diet shifts could result from changes in teeth morphology, jaw teeth strength, body size and sensory sensitivity of the peripheral ( Kempster et al, 2013 ; Lim et al, 2019 ; Nordell, 1994 ; Smith & Merriner, 1985 ). Ontogenetic diet shifts may also result from different energetic needs as well as local prey availability coinciding with ontogenetic differences in distribution ( Lim et al, 2019 ).…”

“…Ontogenetic diet shifts could result from changes in teeth morphology, jaw teeth strength, body size and sensory sensitivity of the peripheral ( Kempster et al, 2013 ; Lim et al, 2019 ; Nordell, 1994 ; Smith & Merriner, 1985 ). Ontogenetic diet shifts may also result from different energetic needs as well as local prey availability coinciding with ontogenetic differences in distribution ( Lim et al, 2019 ). Regardless, ontogenetic diet shifts could suggest that different life stages fulfil different trophic roles and affect food webs differently.…”

Where land meets sea: Intertidal areas as key‐habitats for sharks and rays

“…small bivalves and shrimp) (Gray et al, 1997). A similar ontogenetic shift was shown for other ray and benthic shark species (Bethea et al, 2007; Clements et al, 2022; Lim et al, 2018). Hollensead et al (2016) describes that juvenile smalltooth sawfishes ( Pristis pectinate , Pristidae) most likely use the edge of intertidal flats to ambush schools of mullet (Mugilidae) leaving the intertidal habitat during receding tide.…”