Ectoparasites increase swimming costs in a coral reef fish

Abstract

Ectoparasites can reduce individual fitness by negatively affecting behavioural, morphological and physiological traits. In fishes, there are potential costs if ectoparasites decrease streamlining, thereby directly compromising swimming performance. Few studies have examined the effects of ectoparasites on fish swimming performance and none distinguish between energetic costs imposed by changes in streamlining and effects on host physiology. The bridled monocle bream (Scolopsis bilineatus) is parasitized by an isopod (Anilocra nemipteri), which attaches above the eye. We show that parasitized fish have higher standard metabolic rates (SMRs), poorer aerobic capacities and lower maximum swimming speeds than non-parasitized fish. Adding a model parasite did not affect SMR, but reduced maximum swimming speed and elevated oxygen consumption rates at high speeds to levels observed in naturally parasitized fish. This demonstrates that ectoparasites create drag effects that are important at high speeds. The higher SMR of naturally parasitized fish does, however, reveal an effect of parasitism on host physiology. This effect was easily reversed: fish whose parasite was removed 24 h earlier did not differ from unparasitized fish in any performance metrics. In sum, the main cost of this ectoparasite is probably its direct effect on streamlining, reducing swimming performance at high speeds.

Finding the best estimates of metabolic rates in a coral reef fish

“…Because oxygen consumption is measured continuously while fish are exercised to exhaustion, swimming respirometry is thought to provide a very accurate estimate of MMR (Farrell and Steffensen, 1987;Plaut, 2001;Shultz et al, 2011). In contrast, SMR is not directly measured using this method, but can be calculated by extrapolating the nonlinear swimming speed-M O2 relationship to a swimming speed of zero Reidy et al, 2000;Korsmeyer and Dewar, 2001;Korsmeyer et al, 2002;Binning et al, 2013). Despite many advantages of this method for measuring MMR, U crit protocols can be time consuming and species that are poor swimmers (e.g.…”

Black spot infection in juvenile steelhead trout increases with stream temperature in northern California

“…In our study, heavily parasitized steelhead felt rough to the touch (CJS, personal observation), suggesting a possible loss of streamlining and increased swimming burden. Increased swimming burden due to ectoparasites has been observed previously for marine fish (Binning et al 2012). Future studies on the fitness effects of the parasitic condition in steelhead are warranted given the potential sub-lethal and lethal effects of black spot disease reported in other species.…”

Efecto del endoparásito Prosorhynchoides sp. (Trematoda: Bucephalidae) en la capacidad de nado sostenido del baunco Girella laevifrons (Osteichthyes: Kyphosidae)

“…La capacidad de nado depende de diversos factores, tales como características propias del pez: morfología de las aletas, edad (Fulton & Bellwood 2002), tamaño (Videler & Wardle 1991, Fulton & Bellwood 2002 y forma corporal del pez (Hammer 1995), así como de factores externos como la temperatura del agua (Videler & Wardle 1991, Green & Fisher 2004, Zeng et al 2009), agentes tóxicos dañinos (Hammer 1995), y la presencia de parásitos (Coleman 1993, Barber et al 2000, Binning et al 2012.…”

“…Los parásitos además pueden ejercer un impacto en la capacidad del hospedero para responder a los estímulos externos, modificando los patrones normales de comportamiento (Binning et al 2012) mediante la alteración de la eficiencia energética sobre la respiración, la circulación, la locomoción o la resistencia física (Barber 2007), lo que consecuentemente afectaría algún aspecto de su movimiento. Por ejemplo, Ascocotyle pachycystis infecta al pez Cyprinodon variegatus obstruyendo su flujo sanguíneo, lo que conlleva a disminuir significativamente el tiempo de nado antes de fatigarse (Coleman 1993).…”