<p><strong> </strong>Isla del Coco National Park (ICNP), Costa Rica, is renowned for its large aggregations of pelagic species, especially sharks (Carcharhinidae and Sphyrnidae), billfish (Istiophoridae) and tuna (Scombridae). The high abundance of these sought after species, attracts commercial fishing vessels that enter the protected waters of the Park. Illegal fisheries thus represent one of the biggest threats to the ecological integrity of this World Heritage Site. The ICNP dedicates important resources to protection and control via regular surveillance patrols, along the 12 nautical miles that have Marine Protected Area (MPA) status. During 2012, 2013 and between January and August 2014, 405 surveillance patrols within the MPA found 108 fishing lines, more than 13 000 hooks, seized more than 500 km of fishing line and 257 pelagic individuals. The yellowfin tuna (<em>Thunnus albacares</em>) was the most abundant species, representing more than 72.3 % of the total catch; seized individuals had a mean total length of 153.35±23.19 cm (Min=90 cm; Max=190 cm); which indicates that most individuals were adults. Analysis of monthly CPUE showed that the highest relative abundance of illegally caught <em>T. albacores</em> was between May and August of each year, with a mean relative abundance of 26.13±54.71, 11.63±23.79, 13.71±24.52 tunas per 1 000 hooks in 2012, 2013, 2014, respectively. This species had a high survival rate (nearly 80 % of the individuals found on the lines were still alive), probably due to the short fishing lines used by illegal fishermen, combined with the swift intervention of rangers. The CPUE of <em>T. albacares</em> found in this study is greater than records in Costa Rica’s Exclusive Economic Zone (0.74 and 0.44 per 1 000 hooks respectively). These results highlight the importance of ICNP as an aggregation site for <em>T. albacares</em> and the need for its effective protection. It is important that ranger intervention continue to be as rapid and effective as possible, in order to decrease the impact of illegal fishing on the marine biodiversity of the ICNP. </p><div> </div>

En el ámbito nivel mundial, el tiburón martillo (Sphyrna lewini) es una de las especies más afectadas por la sobrepesca y el aleteo. Recientemente se incorporó a la Lista Roja de la UICN como especie en peligro de extinción. El presente estudio pretendió caracterizar la pesca y la distribución de S. lewini en la parte externa del Golfo de Nicoya. Para lograr este propósito, se realizaron muestreos entre marzo del 2006 y mayo del 2007 y se analizaron los tiburones martillo capturados por pescadores artesanales afiliados a la Cooperativa artesanales de Pescadores de Tárcoles (CoopeTárcoles R. L.), que faenan en la parte externa del Golfo de Nicoya. Para cada tiburón, se determinó la longitud total, la zona de pesca donde se capturó y el arte utilizado. En total se analizaron 273 tiburones. Se identificó un área de crianza primaria en el Peñón y se determinó que existe una relación lineal positiva entre la longitud total y la profundidad de la zona de pesca (R2 = 0.4296; p ‹ 0.0001), y la longitud total y la distancia de la zona de pesca de la desembocadura del río Grande de Tárcoles (R2 = 0.4052; p ‹ 0.0001). Los tiburones de menor tamaño (crías) se encontraron en la zona del Peñón, donde las aguas son poco profundas, turbias y productivas, ofreciendo a las crías alimento y protección de los depredadores. Por lo cual, se recomienda proteger esta zona, en particular en marzo, abril y mayo, época de nacimiento de las crías.The scalloped hammerhead shark (Sphyrna lewini) is one of the shark species most impacted by overfishing, and is currently listed by the IUCN Red List as an Endangered.  This research sought to characterize the distribution of S. lewini in the external area of Gulf of Nicoya, central Pacific coast of Costa Rica, based on observations from a coastal artisanal fishery. From March 2006 to May 2007, we analyzed scalloped hammerhead shark landings by members of the Tarcoles Artisanal Fishermen's Cooperative (CoopeTárcoles R. L.), who operate in the outer part of the Gulf of Nicoya. We measured the total length of each shark, recorded the reported location of capture, and the gear used. In total, we recorded data for 273 sharks landed. We determined that total length holds a positive linear relationship with the depth of the fishing area (R2 = 0.4296, *** p <.0001) as well as with the distance from the mouth of the Tárcoles River (R2 = 0.4052, *** p <.0001). The smaller sharks (pups) were caught in a fishing site known as Peñon, slightly north of the mouth of the Tarcoles River, where the waters are shallow, turbid and highly productive, providing food and shelter for the pups.  As pups mature and attain larger sizes, they move towards deeper waters away from the Tarcoles River, out of the Gulf of Nicoya. We identify Peñon as a primary nursery for scalloped hammerhead sharks, and recommend management actions that seek to reduce fishing effort between March and May, when pups are born.

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En Golfo Dulce, Costa Rica, se han reportado capturas incidentales de S. lewini por pescadores artesanales. Debido a esto, este estudio tiene como objetivo caracterizar las capturas del tiburón martillo en Golfo Dulce, y recomendar pautas de manejo. Entre mayo 2010 y mayo 2011 se recopiló información biológica-pesquera de tiburones capturados durante faenas artesanales en Golfo Dulce. Se estimó la captura por unidad de esfuerzo a lo largo del año. Se analizaron un total de 315 tiburones, todos juveniles, con una longitud total media de 74.3±17.4cm. Las longitudes totales y la abundancia relativa tuvieron tendencias opuestas: en julio-agosto cuando las longitudes totales medias fueron menores, las capturas por unidad de esfuerzo fueron mayores. Debido a esto, se recomienda implementar vedas temporales durante el periodo de nacimiento de las crías de tiburón martillo (junio-agosto) en sitios donde se reportaron las mayores capturas.

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Se analizaron las capturas de tiburones y rayas látigo realizadas por pescadores artesanales de Tárcoles  en el Pacífico de Costa Rica, desde febrero del 2006 hasta febrero del 2007. Se observaron 415 faenas de pesca (línea de fondo, trasmallo y línea rayera): 340 correspondieron a observaciones de descarga y 75 (18.1%) a observaciones a bordo. Durante las descargas se analizaron 3299 tiburones y rayas látigo: el tiburón mamón enano (Mustelus henlei) dominó en la captura total (63.7%), seguido por el tiburón mamón común (Mustelus lunulatus) (16.7%), el tiburón picudo común (Rhizoprionodon longurio) 6.9% y el tiburón martillo común (Sphyrna lewini) 6.1%. A su vez, la raya látigo (D. longa) y el tiburón picudo fucsia (Nasolamia velox) representaron un 3.5% y 2.6% de la captura total, respectivamente. En los 75 viajes a bordo se capturó un total de 6.458 peces, de los cuales solo el 4.4% (240 individuos) fueron tiburones y rayas látigo. M. henlei fue nuevamente la especie más abundante (50.4%), le siguieron R. longurio (21.7%), D. longa (13.8), N. velox (5.8%), S. lewini (5.8%), y por último, M. lunulatus (2.5%). Debido a la estacionalidad y abundancia de tiburones mamones en la zona de Herradura, se recomienda un cierre técnico en enero-febrero y setiembre-octubre, meses con las mayores capturas. También se recomienda la protección de la zona del Peñón, ya que es utilizada por la raya látigo y por los juveniles del tiburón martillo.From February 2006 to February 2007, we analyzed shark and rays captures by the artisanal fishermen from Tárcoles, in the Pacific of Costa Rica. We observed 415 fishing operations (bottom line, gillnet and ray line): 340 dock landing observations and 75 (18.1%) on board observations. During the landing observations, we analyzed 3299 sharks and rays: the brown smooth hound (Mustelus henlei) was the most common species (63.7%), followed by the common smooth hound (Mustelus lunulatus) (16.7%), the Pacific sharpnose shark (Rhizoprionodon longurio) (6.9%) and the scalloped hammerhead shark (Sphyrna lewini) (6.1%). The longtail stingray (Dasyatis longa) and the whitenose shark (Nasolamia velox) represented the 3.5% and 2.6% of the total catch, respectively.  During 75 fishing trips, we analyzed 6.458 fish individuals, of them only 4.4% (240 individuals) were sharks and longtail stingrays. Among these, M. henlei was also the most abundant species (50.4%), followed by R. longurio (21.7%), D. longa (13.8%), N. velox (5.8%), S. lewini (5.8%), and M. lunulatus (2.5%). Considering the seasonality and abundance of smooth hound sharks in Herradura, we recommend a technical closure during the higher catch months (January-February and September-October). Also, we recommend protecting the Peñón, which is inhabited by adults of longtail stingray and juvenile scalloped hammerhead sharks.

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<p>The Scalloped hammerhead shark, <em>Sphyrna lewini</em> is a coastal and pelagic circumglobal species that resides within coastal warm temperate and tropical seas. <em>Sphyrna lewini</em> exhibits strong intraspecific segregation: neonates and young-of-the-year spend the first part of life in coastal inshore waters (nursery grounds), while adults migrate offshore, returning to protected nursery habitats for mating and pupping. On December 3, 2014, at approximately 19:00 hr, four young-of-the-year <em>S. lewini</em> were caught with hand line in Wafer Bay, Isla del Coco, Costa Rica (5°32’42.4” N - 87°03’45.3” W). A total of three males (total length (TL): 73, 73, 76 cm) and one female (TL: 75 cm) were recorded. The presence of these individuals at Isla del Coco suggests that a pregnant female gave birth in or near Wafer Bay, which may be a nursery ground for <em>S. lewini</em>. We recommend further study to evaluate the presence and movements of young-of-the-year and juvenile <em>S. lewini</em> in Wafer Bay to determine if this was an isolated incident or if the bay is a nursery ground for <em>S. lewini</em>.</p><div> </div>