Size-specific clearance rates of the ctenophore Mnemiopsis leidyi based on in situ gut content analyses

• The ctenophore Mnemiopsis leidyi can consume large amounts of zooplankton prey.However, quantitative measurements of feeding rates, based on field data, arescarce. We measured the time required by the invasive M. leidyi to digest naturallyoccurring prey species in the Gullmar fjord, Sweden. Digestion times were relatedto prey size and type, number of prey in the gut and size of the predator. Largeprey species or many prey in the gut resulted in longer digestion times comparedwith small or few prey, but digestion time also varied with the size of M. leidyi. Theprey- and predator-specific digestion times were used together with in situ preyconcentrations and gut contents of M. leidyi to calculate the clearance rates.Clearance rate as a function of ctenophore size is presented for the most abundantmesozooplankton: Acartia sp., Oithona sp., Oikopleura dioica and Penilia avirostris. Onthe basis of the relation between digestion time and the carbon content ratiobetween prey and predator, we discuss the possible effects of mixed prey assemblageson the estimates of clearance rates.

Subject headings

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Keyword

digestion time

Gullmar fjord

gut evacuation

prey selection

Gullmar fjord; prey selection; digestion time; gut evacuation

Publication and Content Type

art (subject category)

ref (subject category)