The status of shark and ray fishery resources in the Gulf of California: applied research to improve management and conservation

Bizzarro, Joseph J. and Smith, Wade D. and Hueter, Robert E. and Tyminski, John and Márquez– Farías, J. Fernando and Castillo–Géniz, J. Leonardo and Cailliet, Gregor M. and Villavicencio–Garayzar, Carlos J. (2009) The status of shark and ray fishery resources in the Gulf of California: applied research to improve management and conservation. Moss Landing, CA, Moss Landing Marine Laboratories, (Moss Landing Marine Laboratories Technical Publication, 09-01)

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Abstract

Seasonal surveys were conducted during 1998–1999 in Baja California, Baja California Sur, Sonora, and Sinaloa to determine the extent and activities of artisanal elasmobranch fisheries in the Gulf of California. One hundred and forty–seven fishing sites, or camps, were documented, the majority of which (n = 83) were located in Baja California Sur. Among camps with adequate fisheries information, the great majority (85.7%) targeted elasmobranchs during some part of the year. Most small, demersal sharks and rays were landed in mixed species fisheries that also targeted demersal teleosts, but large sharks were usually targeted in directed drift gillnet or, to a lesser extent, surface longline fisheries. Artisanal fishermen were highly opportunistic, and temporally switched targets depending on the local productivity of teleost, invertebrate, and elasmobranch fishery resources. Major fisheries for small sharks (< 1.5 m, “cazón”) were documented in Baja California during spring, in Sonora during autumn–spring, and in Sinaloa during winter and spring. Triakid sharks (Mustelus spp.) dominated cazón landings in the northern states, whereas juvenile scalloped hammerheads (Sphyrna lewini) primarily supported the fishery in Sinaloa. Large sharks (> 1.5 m, “tiburón”) were minor components of artisanal elasmobranch fisheries in Sonora and Sinaloa, but were commonly targeted during summer and early autumn in Baja California and Baja California Sur. The pelagic thresher shark (Alopias pelagicus) and silky shark (Carcharhinus falciformis) were most commonly landed in Baja California, whereas a diverse assemblage of pelagic and large coastal sharks was noted among Baja California Sur landings. Rays dominated summer landings in Baja California and Sinaloa, when elevated catch rates of the shovelnose guitarfish (Rhinobatos productus, 13.2 individuals/vessel/trip) and golden cownose ray (Rhinoptera steindachneri, 11.1 individuals/vesse/trip) primarily supported the respective fisheries. The Sonoran artisanal elasmobranch fishery was the most expansive recorded during this study, and rays (especially R. productus) dominated spring and summer landings in this state. Seasonal catch rates of small demersal sharks and rays were considerably greater in Sonora than in other surveyed states. Many tiburón populations (e.g., C. leucas, C. limbatus, C. obscurus, Galeocerdo cuvier) have likely been overfished, possibly shifting effort towards coastal populations of cazón and rays. Management recommendations, including conducting demographic analyses using available life history data, determining and protecting nursery areas, and enacting seasonal closures in areas of elasmobranch aggregation (e.g., reproduction, feeding), are proposed. Without effective, enforceable management to sustain or rebuild targeted elasmobranch populations in the Gulf of California, collapse of many fisheries is a likely outcome. (PDF contains 243 pages)

Item Type: Monograph or Serial Issue
Title: The status of shark and ray fishery resources in the Gulf of California: applied research to improve management and conservation
Personal Creator/Author:
CreatorsEmail
Bizzarro, Joseph J.
Smith, Wade D.
Hueter, Robert E.
Tyminski, John
Márquez– Farías, J. Fernando
Castillo–Géniz, J. Leonardo
Cailliet, Gregor M.
Villavicencio–Garayzar, Carlos J.
Series Name: Moss Landing Marine Laboratories Technical Publication
Number: 09-01
Date: 2009
Publisher: Moss Landing Marine Laboratories
Place of Publication: Moss Landing, CA
Latitude: 28
Longitude: -112
Funders: David and Lucile Packard Foundation
Issuing Agency: Moss Landing Marine Laboratories
Additional Information: This report is bilingual and has been published in both Spanish (http://aquacomm.fcla.edu/2423/) and English.
Uncontrolled Keywords: shark; ray; fishery; Gulf of California
Subjects: Fisheries
Item ID: 2422
Depositing User: Joan Parker
Date Deposited: 08 Jul 2009 20:16
Last Modified: 29 Sep 2011 19:01
URI: http://aquaticcommons.org/id/eprint/2422

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