JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The Association for Tropical Biology and Conservation is collaborating with JSTOR to digitize, preserve and extend access to Biotropica. ABSTRACTGill nets set at three depths at an open-water station in Lake Titicaca during August 1984 captured only two species of endemic killifishes (Orestias ispi and 0. mulleri) and an exotic silverside (Basilichthyes bonariensis). These species segregated strongly by depth, with B. bonariensis and 0. mulleri occurring only in the surface and bottom sets, respectively, and 0. ispi being most abundant in the mid-water set. All three species were feeding on zooplankton, but 0. mulleri also included benthic crustaceans in its diet. Copepods were strongly selected by large (>200 mm SL) B. bonariensis, whereas smaller size classes ate mainly cladocerans.

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Understanding the feedbacks between food systems and conservation policies can help avoid unintended environmental consequences. Using a survey-based choice experiment and economic modeling, we quantify the potential impact of tourists' responses to a shift in offshore fish supply after the designation of a large-scale marine protected area in Palau. We find that this conservation policy may increase offshore fish prices and tourists' consumption of reef fish, thereby further endangering local reef ecosystems. However, if tourists are offered a sustainable offshore choice, their demand for fish could be kept at current levels, and environmental impacts from increased reef fish consumption would be avoided.

1. Giant clams (subfamily: Tridacninae) are an important food and economic resource for the Republic of Palau and the greater Indo-Pacific region. However, giant clam diversity and distribution data for Palau are out of date. 2. This study reports the species diversity and distribution of giant clams across the Palauan archipelago (total survey area of 3,300 2 m) from data collected between 2015-2017. 3. This is the first documented finding of Tridacna noae in Palau, however, it was rare. Only four individuals were found at only two locations. 4. Results show that Palau is home to a diverse and abundant population of giant clams. Tridacna crocea (an important food and economic resource) exhibited the highest abundance, with an average of 20.0 ± 2.9 individuals per 50 m 2 . Tridacna maxima and Tridacna squamosa were ranked next in abundance. In contrast, T. noae, Tridacna derasa, Tridacna gigas, and Hippopus hippopus were found in low numbers or only found in few locations.5. The density of all recruits, juveniles, and adult T. crocea and T. maxima did not differ significantly between conservation areas and open fishing sites, which suggests the possibility that ecological factors such as habitat loss, acute weather events, or changes in sea surface temperatures could be impacting replenishment or recruitment. However, one protected area was found to have a higher abundance of T. crocea recruits and adults, which suggests that protection from fishing may have increased recruitment rates and lowered mortality rates at this site.6. Taken as a whole, clam populations in Palau remain reasonably abundant and healthy. As demand for giant clams continues to rise in Palau and the region, local regulations should focus on sustainable fishing practices by establishing size limits, species bans, and long-term monitoring plans to maintain the diverse populations of giant clams found there.

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