BYCATCH OF THE ARTISANAL SHRIMP FISHERY IN THE GULF OF CALIFORNIA (SONORA AND SINALOA) MEXICO Report prepared by Alejandro Balmori Ramírez (INAPESCA, CRIP-Guaymas) and Rufino Morales Azpeitia (CIBNOR-Unidad Guaymas), in collaboration with Everardo Miranda Mier and Jesús Guadalupe Padilla Serrato. Guaymas, Sonora, México. June 2012 Summary One of the most important fishing resources in Mexico is shrimp, this is due to its high economic and social value. Nonetheless, many non-target species are captured incidentally during shrimp-fishing activities, and grouped as faunal companions or shrimp bycatch (SBC). Most of the SBC species have not been studied and the impact of this fishery upon them is yet unknown. This document presents the results of a study on the artisanal shrimp fisheries’ bycatch within the bays of Guaymas, Bahía de Lobos, and El Tóbari, in the State of Sonora; and in Santa Maria La Reforma in the State of Sinaloa, during the 2011–2012 shrimp fishing season. The study collected shrimp and SBC samples, identified the organisms to the species level, and recorded biological sampling (biometrics). Logbook data and sampling information was captured in a database. We documented 854 fishing hauls for all of the bays. SBC analysis shows a total composition of 46 identified species belonging to different taxonomic groups such as fishes, crustaceans, gastropods, and elasmobranchs, and an additional 10 species identified to the genus level only. The most diverse group was that of bony fishes and the most dominant species was the swimming crab (Callinectes spp.). The amount of SBC species varied spatially (lagoon system). During the shrimping activity, a high percentage (20-30%) of negative fishing hauls (i.e., without any SBC captures) was recorded, indicating that the artisanal shrimp fishery does not generate any bycatch in a third of all fishing hauls. The SBC shrimp ratio average for all bays was 1:0.5, and ranged from 1:0.28 to 1:10.5 — a lower proportion than the reported ratios of 1:8 (Amezcua et al. 2006) and 1:22 (Suenaga 2010). SBC species are mostly discarded (75%), with only some species being retained (25%), and these are used for their commercial value and for family consumption (e.g., sand bass (Paralabrax maculatofasciatus), sierra (Scomberomorus sierra), seabass (Cynoscion spp.), mojarras (Eucinostomus spp.), and swimming crabs (Callinectes spp.)). Regarding species under special protection, only one individual of Mycteroperca jordani was captured, a species classified as endangered according to the IUCN, although its frequency of occurrence is 0.003 per thousand fishing hauls. We concluded that the impacts of the artisanal shrimp fishery upon the SBC are low, due to the low amount of bycatch that is generated, the low ratio of the capture to SBC species, and the lack of presence of threatened or endangered species in the SBC. Finally, it is recommended to continue studying the SBC during other fishing seasons and to analyze the population dynamics of the dominant species to determine the health status of these populations, since they may be indicative of impacts. INTRODUCTION In Mexico, fishing is important because of its annual production volume of about 1.5 million metric tons and the number of people who depend on it directly or indirectly (SAGARPA 2007). However, when any resource is fished, the capture includes non-target species, commonly known as faunal bycatch (FBC). The shrimp bycatch (SBC) represents the species of flora and fauna that are not a target of this fishery, and is known throughout the world as "bycatch" or as "non-target" species (FAO 1997). Global estimates of SBC range from 5 to 16 million metric tons, with shrimp fisheries generating the highest incidental catch volumes, with a ratio of shrimp to SBC of about 1:5 in temperate or subtropical waters and of 1:10 in tropical areas (FAO 1999). It is estimated that annually between 3 and 7.5 million metric tons of SBC are discarded in the world (Allsop 1977, Morgan and Chuenpagdee 2003, and Kelleher 2005). In particular, the offshore shrimp trawling fishery, with larger vessels, contributes to the bycatch problem due to the fishing system used: the trawl net. Although bycatch is also captured by smaller boats (pangas) using other fishing gear such as cast nets, trawl nets (“change” nets), suripera nets, and gillnets (Amezcua et al. 2006; SEMARNAP, INAPESCA 2000). Fishing activities are particularly striking in a marine environment, directly affecting almost all habitats except for the deep sea, where no fishing takes place. Even with the more restrictive management practices enforced today, fisheries can have deep impacts on the marine environment, ranging from overexploitation of species due to extraction, to incidental capture problems, habitat alteration, genetic changes in populations, and affecting the structure of food webs (Anonymous, 2000). The problem of bycatch has gained importance in recent decades, and viable solutions have been sought, ever since the FAO Technical Conference on Fishery Products was held in Tokyo in 1973, and later the conference of the International Research Center for Development in held Bangkok in 1974 (Pérez-Mellado et al. 1982). Since then and until the present, there have been a series of international workshops in search for solutions. Shrimp is one of the most important resources due to its high economic value, generating trade income for the country and supplying a source of employment. Some estimate it creates 37,000 jobs (SAGARPA, 2006). However, shrimp fishing is strongly criticized for its high SBC capture rates. In the Gulf of California, the SBC captured by fishing vessels comprises approximately 242 benthic-demersal fish species, as well as crustaceans, mollusks, and echinoderms, with fish being the dominant group (Nava- Romo 1994, López-Martínez et al. 2010, Madrid-Vera et al. 2010). Only a few of the SBC species have been studied (López-Martínez et al. 2007, Rábago Quiroz et al. 2008, González-Ochoa et al. 2009, Arzola-Sotelo 2010, Morales-Azpeitia et al. 2011). Fishing vessels contribute between 60 and 70% of the total shrimp production, operating with two trawl nets with an average length of 95 feet (Heredia-Quevedo 2001). These nets are distinguishable by their lack of selectivity, since they capture large volumes of fish, crustaceans, and mollusks (López-Martínez et al. 2000, 2007, Alverson et al. 1996; Pérez-Mellado 1998). The artisanal Sonoran vessels that fish for shrimp in the riverside zone mainly employ entanglement nets, also known as “chinchorro de línea”; in the State of Sinaloa, fishermen employ a fishing gear known as the “suripera”, whish is a modified cast net. Many SBC species are captured during these fishing activities, but before this report, they had not been studied (Amezcua et al. 2006, Suenaga 2010). This study will determine the specific composition of organisms caught in the artisanal shrimp fishery within the main shrimping bays in the Gulf of California, particularly in the States of Sonora and Sinaloa. Importance of the shrimp resource Mexico has large areas of coastline, bays, and estuarine systems, all with great diversity of species. Among the most important groups found in the region are crustaceans, the group to which penaeid shrimps belong to (Leal-Gaxiola 1999). The shrimp fishery is one of the most important in the country, generating a large number of jobs. It is also one of the products that finds a high price in the international markets, generating high foreign exchange earnings for the country (Avila-Pardo 2001). Currently, Mexico is among the world’s top ten shrimp producers (Gillett 2010). The Mexican shrimp production yield in the year 2000 was of around 70,144 metric tons (MT), with 52% corresponding to the Pacific coast’s production, and the states of Sonora and Sinaloa its main producers (Herrera-Valdivia 2002). Usually, only two species of shrimp are exploited, the blue shrimp (Litopenaeus stylirostris) and the brown shrimp (Farfentepenaeus californiensis) (López-Martínez 2000). The development of an artisanal fishery encourages the employment of large numbers of fishermen, who are organized into cooperatives, creating opportunities for economic development in their coastal communities; additionally, they produce food for human consumption, both locally and regionally. Currently, however, the economic return from this fishery is considered at the point of a full collapse (Cruz-Romero et al. 1996), due to lower catches and lower prices (Padilla-Serrato 2005). Background The shrimp resource is exploited by two fishing fleets, the first is composed of larger offshore vessels (ship) and the second, known as the bay or artisanal fleet, consists of smaller panga-type boats. The bays in the states of Sonora and Sinaloa maintain constant contact with the sea, and due to their higher evaporation rates they have higher salinity conditions than the surrounding marine area. The dominant species of shrimp in Sonora is the blue shrimp, Litopenaeus stylirostris (Hernandez-Carballo and Macías 1996), with 90% of the catches, and therefore the coastal fisheries in the state are of great importance due to the higher market value of this species in the US market. This fishery is carried out during the species' different life stages and within different bodies of water: one taking place within protected bodies (bays and estuaries), in which artisanal-type fishing systems are used, and the other using larger offshore vessels (García-Bourbon et al. 1996). The shrimp fishery inside protected waters dates back to pre-Hispanic times, and it is the oldest in the Mexico. The main states where this fishery is done are: Sinaloa, Sonora, Chiapas, Oaxaca, Nayarit, and Baja California Sur (Hernandez-Carballo and Macías 1996). The fishery inside the lagoon systems of Sonora is based in the southern part of the state, the most productive bays being: Guásimas, Lobos, Huatabampo, Yávaros, and Agiabampo.