Since 1997, dolphin watching activities have increased in Patagonia, with dusky and Commerson’s dolphins as the target species. To assess impact of this activity, tours were monitored. For dolphins, number tourists from 1,393 1997 to 1,840 2000. The encounter rate grew 25% during 1999 90% 2001. Most groups observed ranged 50-100 animals. Data recorded both a commercial research boat. Dusky showed short-term reaction boats feeding was most affected behaviour. 532 2,113 averaged 95.58%. There...

Since 1989, interactions between marine mammals and fisheries have been monitored along the Atlantic Patagonian coast.The Argentinian national fishing fleet in area is composed of approximately 208 vessels (75% trawlers; 16% jiggins; 9% longliners).The operates year-round from eight harbours Escondida Island San Jorge Gulf (80 000 naut. miles 2 ).The important target species are: hake (Merluccius hubbsi), shortfin squid (IIlex argentinus) shrimp (Pleoticus muelleri), while several tons other...

Abstract This paper reports on aerial surveys conducted to estimate the relative abundance and trend in growth of southern right whale ( Eubalaena australis ) population from Península Valdés. The number whales counted tripled 1999 2016. We modeled whales, calves, solitary individuals breeding groups using as predictive variables year, Julian day, day 2 by means generalized linear models. rate increase decreased near 7% 2007 0.06% 2.30% for total respectively Trends rates calves were...

Abstract Understanding the recovery of whale populations is critical for developing population-management and conservation strategies. The southern right (SRW) Eubalena australis was one baleen species that has experienced centuries exploitation. We assess here first time population dynamics SRW from southwestern Atlantic Ocean at regional level to measure numerically effect whaling estimate trend after depletion. reconstructed catch history period 1670–1973 by an extensive review different...

Teeth provide valuable information about an individual's life cycle and serve as a powerful tool for visualizing population-level changes associated with density-dependent processes. In pinnipeds, teeth are used to estimate the age of individuals based on count growth layer groups (GLG) in dentine. this study, we analyzed tooth size GLG widths canines Otaria byronia throughout past 100 years, linking these fluctuations population abundance. A total 76 male from Patagonia were analyzed,...

Fil: Coscarella, Mariano Alberto. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Patagonico; Argentina. Universidad la Patagonia; Argentina

Site fidelity is considered as an animal's tendency to return a previously occupied place; this component of animal behaviour that allows us understand movement patterns and aspects related the life history. Although there are many site metrics, lack standardisation presents considerable challenge in terms comparability among studies.This investigation focused on theoretical development standardised composite index its statistical distribution order obtain reliable population-level...

Since the 1980s, distribution range of southern right whale (Eubalaena australis) in Argentina was mostly located winter calving grounds around Península Valdés. After international moratorium that forbade commercial hunting, whales have shown signs recovery during last few decades. Nowadays, it is thought species experiencing a density-dependent process while expanding its Patagonia. From 2007 to 2016, data on distribution, group composition and relative abundance were collected Golfo San...

The management scheme of Marine Protected Areas (MPAs) includes monitoring protocols but such activities are not always carried out. This is the case for Golfo San José, a MPA in northern Patagonia, Argentina. It was created 1975 protection southern right whale ( Eubalaena australis ) breeding grounds. Other components system, as dolphin populations have received little attention. study first attempt to estimate sighting rates, group size and overall abundance bottlenose Tursiops truncatus...

We investigated the association patterns of 48 identifiable Commerson's dolphins (Cephalorhynchus commersonii) photographed 2 or more times over a 2-year period in Bahía Engaño, Chubut, Argentina. The associations among them were not different from random for short time periods (7 days) but significantly longer periods. Lagged identification rate and lagged models show that remained area on average 15 days then moved away as original groups dissolved. appear to have fission–fusion society,...

The study of food habits the broadnose sevengill shark (Notorynchus cepedianus) based on observation stomach contents 22 individuals, revealed importance marine mammals as part shark's diet. analysis showed that represent at least 30% total consumed biomass by sharks. frequency occurrence was estimated to be 35%. three pinnipeds with local distribution and two species cetaceans were consumed. Although consumption mammal high, there no evidence direct attack living preys N. cepedianus, in...

Information on the incidental mortality of dusky and common dolphins in mid-water trawl fisheries along Argentine shelf was obtained for 1990s. The anchovy is believed to be an under-exploited resource usually taken purse seine fisheries. However, few occasions when it target species large trawlers, anchovy-eating were incidentally caught. A incidents accounted relatively high numbers but most cases information insufficient detailed analysis. For three cases, however, sufficient estimate...

Abstract We inspected dusky dolphin ( Lagenorhynchus obscurus ) group dynamics in Golfo Nuevo and found differences social organization between cold warm seasons. Surveys were conducted onboard a research vessel, from which we collected behavioral observations fission‐fusion data 2001 to 2008; also photo‐identification 2004 2012. To analyze association patterns, calculated half‐weight index (HWI) differentiation S ). Monte Carlo permutation test determine whether observed patterns...