Marine protected areas facilitate parasite populations among four fished host species of central Chile

Abstract

Summary1. Parasites comprise a substantial proportion of global biodiversity and exert important ecological influences on hosts, communities and ecosystems, but our knowledge of how parasite populations respond to human impacts is in its infancy. 2. Here, we present the results of a natural experiment in which we used a system of highly successful marine protected areas and matched open-access areas in central Chile to assess the influence of fishing-driven biodiversity loss on parasites of exploited fish and invertebrate hosts. We measured the burden of gill parasites for two reef fishes (Cheilodactylus variegatus and Aplodactylus punctatus), trematode parasites for a keyhole limpet (Fissurella latimarginata), and pinnotherid pea crab parasites for a sea urchin (Loxechinus albus). We also measured host density for all four hosts. 3. We found that nearly all parasite species exhibited substantially greater density (# parasites m À2 ) in protected than in open-access areas, but only one parasite species (a gill monogenean of C. variegatus) was more abundant within hosts collected from protected relative to openaccess areas. 4. These data indicate that fishing can drive declines in parasite abundance at the parasite population level by reducing the availability of habitat and resources for parasites, but less commonly affects the abundance of parasites at the infrapopulation level (within individual hosts). 5. Considering the substantial ecological role that many parasites play in marine communities, fishing and other human impacts could exert cryptic but important effects on marine community structure and ecosystem functioning via reductions in parasite abundance.

Environmental change and the ecology of infectious disease

“…A similar result arose from a comparison of the parasites of exploited host species inside and outside of marine reserves in central Chile, where a subset of parasites with particular traits (in this case, short transmission distances) responded to protection of their hosts with marked increases in prevalence ( 4). These general patterns were also confirmed in a meta-analysis of studies reporting the composition of parasite assemblages in marine reserves and matched open-access areas ( 5).…”

Reproductive output of two benthic resources (Fissurella latimarginata and Loxechinus albus) under different management regimes along the coast of central Chile

“…In fact, the 20 to 25% increases in gonad weight observed in the scallop Pecten maximus between protected and open access areas suggest that protection can directly affect reproductive investment (Kaiser et al, 2009). However, negative effects can also be expected under density-dependent feeding, or parasitism scenarios (Loot et al, 2005;Wood et al, 2013). For instance, infection rates of several invertebrate species, including the keyhole limpet Fissurella crassa, are significantly higher in marine protected areas (Loot et al, 2005;Wood et al, 2013).…”

“…However, negative effects can also be expected under density-dependent feeding, or parasitism scenarios (Loot et al, 2005;Wood et al, 2013). For instance, infection rates of several invertebrate species, including the keyhole limpet Fissurella crassa, are significantly higher in marine protected areas (Loot et al, 2005;Wood et al, 2013). However, the higher abundance of parasites infecting the gonads of Fissurella spp.…”

Fishing drives declines in fish parasite diversity and has variable effects on parasite abundance

“…In the Atlantic lowlands of Costa Rica, McKenzie (2007) found that, among three species of amphibian hosts collected from clear-cut cattle pasture and forest habitats, six metazoan parasite species were more abundant in pasture than forest, two species were more abundant in forest than pasture, and 13 species did 3 Present address: Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado 80309 USA. Some have found higher parasite abundance and diversity in reserves than in open-access areas (Sasal et al 1996, Bartoli et al 2005, Loot et al 2005, Wood et al 2013, while others have found higher parasite abundance in open-access areas (Sonnenholzner et al 2011), or have failed to find significant differences in abundance and diversity between reserve and openaccess areas (Ternengo et al 2009). Aeby et al (2011) found that, while prevalence of growth anomalies (a tumor-like disease of unknown etiology) of Porites spp.…”