24 JFLS | 2019 | Vol 4(1) | Pp 24-28 Research Article Management of a Marine Park: analysis of recreational and illegal fishing pressures on the reef fish assemblage at Los Arcos Reserve in Jalisco, Mexico Kirsten Stokes 1 , Kelly Scammon 2 , Darian Double 3 , Katie Toon 4 , Shelli Hendricks 5 , Aldo Alfonso Zavala Jimenez 6 , Karla De La Pena 7 and Katherine Comer Santos 8 * 1 Kirsten Stokes Orlando County Public School District, 445 W. Amelia St., Orlando, FL 32801 2 Kelly Scammon Roger Williams University, One Old Ferry Road, Bristol, RI 02809 3 Darian Double Ross School of Business, 701 Tappan Street, Ann Arbor, MI 48109 4 Katie Toon Pitzer College, 1050 N. Mills Avenue, Claremont, CA 91711 5 Shelli Hendricks Fielding Graduate University School of Leadership Studies, 2020 De la Vina Street, Santa Barbara, California 93105 6 Aldo Alfonso Zavala Jimenez Centro Universitario de la Costa, Universidad de Guadalajara, Av. Universidad #203, Puerto Vallarta, Jalisco, México 48280 7 Karla De La Pena Boca Divers, Calle Pelicanos 518, Boca de Tomatlán, Jalisco, México 48292 8* Katherine Comer Santos The Science Exchange Internship Program, a project of the Ocean Foundation, 1320 19th St NW Floor 5, Washington, DC 20036 ISSN: 2456-6268 ABSTRACT Illegal fishing activities are a worldwide threat affecting all ocean basins. At the Los Arcos Marine Reserve, located in Puerto Vallarta, Jalisco, Mexico management problems include overcrowding of tourist boats and illegal fishing activities. There is little enforcement of regulations due to lack of government personnel and resources. We took 30 systematic censuses of reef fish and recreational activities (boating and fishing) over two summer months in 2017 and 2018 to document species richness, fish densities, fish sizes, sea surface temperatures, and threats in the reserve. We identified 67 unique species during the study period, mostly small reef fish less than 81 cm total length. Species richness and densities were significantly higher in 2017 compared to 2018 (richness T=2.37; p=.040 and density T=2.16; p=.047). This could be related to significantly fewer boats and fishers in 2017 with buoys installed by a non-profit group to keep boats away from divers (T=-2.10; p=.045). In 2017, we found the expected significant negative trend between high recreational activity and low fish density (r 2 = - 0.52; p=0.02) but in 2018 we found the opposite trend (r 2 =0.31; p=0.02). Removal of the buoys in 2018 apparently allowed SCUBA and snorkel tour operators to get closer to the Aquarium transect site and attract fish with bread bait. In general, Los Arcos species richness and densities are higher than other nearby areas and reserves. The team recommends education over enforcement to reduce illegal fishing activity and overcrowding of tour boats in this protected area in order to allow fish stocks to flourish, not only for their ecological roles, but also for the economic well-being of the local communities that depend on them for their livelihoods. © 2019 The Authors. Published by JFLS. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0). ARTICLE INFO Received: 22 January 2019 Accepted: 22 June 2019 Available online: 30 June 2019 KEYWORDS Marine Park Illegal fishing Jalisco * CORRESPONDENCE katherine@thescienceexchange.org INTRODUCTION Illegal fishing activities are a worldwide threat affecting all ocean basins. The situation is confounded when governments lack resources to monitor and enforce regulations, and when fishers come from low-income communities. Both these conditions exist in our study area. Los Arcos National Marine Reserve is one of the most popular diving and snorkeling sites in Puerto Vallarta, Mexico. The reserve was decreed in 1975 with 3.14 km 2 of protected waters (1 km radius around the arches for which the park is named) where no fishing of any kind is allowed, and violators are subject to sanctions by fisheries authorities (Carabias Lillo et. al., 2000). However, locals complain that it is just a “paper park”, and we observed that there is overcrowding of tourist and fishing boats, and illegal fishing