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Mohamed bin Zayed Species project number 11252181

The Chondrichthyans Research Group, called CONDROS (www.condros.com.ar), was created in 2007 as a part of the Ictiological Resource Lab in the Institute of Marine Biology and Fisheries Alte. Storni (IBMP Alte Storni), San Antonio Oeste, Río Negro, Argentina. The main objective of the group is the study of the biology, ecology, behaviour and reproducitve patterns of sharks, rays and chimaeras to preserve and manage this resource. In 1999 the Fishing Committee of FAO creates the International Action Plan for the conservation and management of sharks in the world (IAP - Sharks). The main objective of this plan is to preserve the shark species from overfishing (directly or by by-catch). From this international plan new local plans were created and executed in each country, including Argentina in 2009. Between the main objectives of this plan are determine critical areas, protect sharks biodiversity and the function and structure of the ecosystem. The knowledge of the habitat use and migration patterns (trophic and reproductive) of the shark Galeorhinus galeus and the ray Atlantoraja castelnaui of the San Matías Gulf (Río Negro, Patagonia, Argentina) are basic information to stablish critical areas for its conservation. All data collected will be linked in a geographical information system (GIS). Thus, this system will contribute to discuss and analyze with the national stakeholders (Federal Fishery Council) new conservation and management strategies to be applied for these species. The results obtained will also contribute to improve the execution of the main objectives of the National Action Plan (PAN - Argentina) and will also add relevant data to the Shark Project of the CONDROS group in Patagonia. The present project will also bring relevant information about the ecological interactions between the top predators in the patagonian marine ecosystem. The information related with the habitat uses of sharks and rays will allow linking it with the trophic ecology data available of these species and estimate, in a non direct way, the impact over the ecosystem. The habitat use information will be analyzed and linked with the data base of other 15 patagonian species, including other top predators of the patagonian marine trophic chain as the argentine hake, southern sea lions, southern sea elephants and the Magellanic penguin, that are been followed using satellites by the Patagonian Sea Conservation Forum to determined common used areas (during space and time) by the main top predators of the patagonian marine ecosystem. Today, the main difficult that faced biologists and stakeholders to manage and preserve sharks and rays species and their populations in the world is the lack of ecological information, work tools and political will.
One female individual of Galeorhinus galeus was collected and tagged inside Bahia Anegada Bay (San Blas Bay Natural Reserve, Northern Patagonia) during spring on November the 11th, 2011, using a rigid inflatable boat and the logistic support of local sportive anglers. Shark was captured with sportive fishing gear using barbless hooks baited with mackerel and Brazilian menhaden. After capture, the fish was brought on-board and the hook was removed. The individual was identified, measured for total length (cm), sex was recorded and tagged with both type of tags. To be sure that the shark behavior was not affected during the tag procedure we put them back into the water, holding the individuals from its caudal fin with both hands, and release them only if they could swim away vigorously. Tagging locations and depth were recorded by using a gps and the boat’s sonar respectively.  All school sharks were tagged using a MK10 satellite pop-up archival transmitting (PSAT) tag with a special stainless steel harpoon.  PSAT tags were inserted at the right side of the base of the dorsal fin in each individual. Tag was secured to the shark intramuscularly with a liquid molding polymer dart (size: 35x14x16 mm) attached to a stainless steel cable leader with chafing protection. The 10 cm length leader fitted with an RD1800 (Wildlife Computers) cut-off was attached with crimps to the burn-pin of the PAT. The RD1800 acts as a mechanical guillotine severing the tether when depth exceeds 1,800 m, preventing the PAT from being crushed. Additionally, a custom-made colour-coded ID tag with a plastic anchor was inserted into the left side of the dorsal fins’ base for future identification of the individuals once the PSAT tag released.
PSAT tag was programmed for a deployment period of 180 days. Data collection frequency was set to every 5 seconds with tags programmed to record water temperature (minimum resolution: 0.05ºC), depth (minimum resolution: 0.5 m) and light level (measured as irradiance at 550 nm wavelength) binned into 6 hours histograms of the following ranges: depth: <10 m, 10 to 20 m, 20 to 30 m, 30 to 40 m, 40 to 50 m, 50 to 60 m, 60 to 70 m, 70 to 80 m, 80 to 90 m, 90 to 100 m, 100 to 125 m,125 to 150 m,150 to 200 m, > 200 m; temperature bins were <3 ºC, 3 to 5 ºC, 5 to 7 ºC, 7 to 9 ºC, 9 to 11 ºC, 11 to 13 ºC, 13 to 15 ºC,15 to 17 ºC, 17 to19 ºC, 19 to 21 ºC, 21 to 23 ºC, 23 to 25ºC, 25 to 27ºC  and  > 27 ºC. Each tag also recorded a temperature-depth profile of the water column inhabited by the shark during each six hour interval. This comprised minimum and maximum water temperatures at eight equally spaced depths, which ranged from the shallowest to the deepest swimming depths. The tag also processed the light level data to correct for depth and then estimated times of dawn, dusk, and midnight or midday. PSAT tags were enabled with the automatic release feature, whereby a tag pops off and begins to transmit when it has been at a constant depth for a pre-set time period. The automatic release feature, in our study, was enabled with tags regarding depth variations ±3 m for 48 hours as constant depth.

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