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In the tropics, variations in the structure and species composition of marine fish parasite communities over several years have received limited attention. Changes in water temperature in the tropics are not as extreme as in temperate climes, and the processes that generate variations in these parasite communities are as yet unclear. The parasite communities in populations of Parapsettus panamensis from four locations on the south-central Pacific coast of Mexico were quantified and analyzed. Four hundred forty-six fish were collected over a 6-year period (2012; 2013; 2016a, b; and 2017). Twenty-three metazoan parasite species were recovered and identified: three species of Monogenea (present as adults); eight species of Digenea (adults); one species of Acanthocephala (juveniles); one species of Cestoda (larvae); three species of Nematoda (two present as adults and one present as larvae); four species of Copepoda; and three species of Isopoda (two present as adults, and one present as larvae). At the component community level, parasite species richness varied significantly from 10 (Marquelia 2016) to 17 species (Acapulco Bay 2012). The component communities and infracommunities of P. panamensis exhibited a similar pattern: low species numbers, low diversity, and dominance by a single parasite species. Parasite community structure and species composition varied between sampling years and locations. The main factors responsible for these variations were host traits such as feeding behavior and body size, and occurrence of a set of distinctive parasite species. K E Y W O R D S marine fish, Mexico, Pacific coast, Parapsettus panamensis, parasites

An important part of the fishing activity in Mexico is carried out in the coastal strip and has a strong social, economic and ecological importance. In the state of Guerrero, mollusks fishing is coastal and craftwork activity focused on a small number of species and without information on biology and reproductive or ecological aspects for most species caught. This research was carried out in the Costa Chica region, Guerrero, Mexico and the aims were: 1) To analyze the socioeconomic features of cooperative societies of fishing production; and 2) To know the diversity of mollusks caught by coastal fishing and the species that have the greatest importance in fishing. From February to April 2013-2015, seven fish coop units, four piers and places where seafood is sold were visited. For the socioeconomic analysis and the determination of the species that have more importance in the coastal fishing, a total of 67 surveys were applied. In order to determine the cast of species, the specimens captured by the fishermen were used, which were identified and counted. A total of 67 interviews were analyzed and an average of $1806.00 was estimated as weekly economic income just as a product of fishing, it was also estimated that on average the fishermen work 4.3 days a week. Fisheries cooperatives market most of their produce directly to restaurateurs and locals on the piers. Replacement of older adults by young fishermen from the same region was observed, most are adults between 22 and 39 years old. 25 species of mollusks of economic importance were registered for the coastal fishermen of the Costa

Acapulco, offers for international tourism a variety of mollusks that are delightful to the palate and a source of economic revenue for its residents; however there are no studies on the species consumed. Furthermore, data from the State agencies responsible for registration of these products are unclear. This work is aimed to develop an inventory of Gastropoda, Bivalvia and Polyplacophora marketed as food, to gain knowledge on the species native to Acapulco and the introduced ones. The places that sell shellfish were interviewed from 2008 to 2011 in order to determine the geographical origin of their products being offered. We identified 42 species: 15 species of gastropods are captured locally and three are introduced. On Bivalvia, seven species are caught locally and 16 are introduced. There are Bivalvia species caught locally; however, their capture is now unaffordable. It is likely that this situation is due to overfishing and/or the transmission of diseases or parasites caused by the introduction of foreign living organisms to Acapulco. Within the list of species caught locally, there are some listed as of subject protection; all of these organisms are exploited in Acapulco without control. The wealth of marine mollusks for human consumption in Acapulco is very high. The capture does not satisfy local market demand and the amount of introduced species is very high. It is necessary to make a diagnostic analysis of mollusk fishing industry in the state of Guerrero, also implement a management program, including the sanitary measures and control of introduced species, as they arrive alive and stay alive in the waters of Acapulco. A significant number of native species that have aquaculture potential should be studied for commercial culture practice as well as to conduct studies on their biology on those species that are considered over-exploited and allow recovery of the species in its habitat.

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