Sawfishes currently are among the most threatened elasmobranchs in the world. Only two species inhabit Atlantic waters: the largetooth sawfish (Pristis pristis) and the smalltooth sawfish (Pristis pectinata), both having suffered dramatic declines in their ranges. The goal of this study was to evaluate the status of P. pristis in the Atlantic, and estimate local extinction risk based on historical and recent occurrence records. In order to accomplish these goals, a thorough search for historical and recent records of P. pristis in the Atlantic was conducted, by reviewing scientific and popular literature, museum specimens, and contacting regional scientists from the species’ historical range. In total, 801 P. pristis records (1830–2009) document its occurrence in four major regions in the Atlantic: USA (n = 41), Mexico and Central America (n = 535), South America (n = 162), and West Africa (n = 48). Locality data were not available for 15 records. Historical abundance centres were the Colorado‐San Juan River system in Nicaragua and Costa Rica (and secondarily Lake Izabal of Guatemala), the Amazon estuary, and coastal Guinea‐Bissau. Currently, the species faces drastic depletion throughout its entire former range and centres of abundance. It appears to have been extirpated from several areas. The probability of extinction was highest in the USA, northern South America (Colombia to Guyane), and southern West Africa (Cameroon to Namibia). Currently, the Amazon estuary appears to have the highest remaining abundance of P. pristis in the Atlantic, followed by the Colorado–San Juan River system in Nicaragua and Costa Rica and the Bissagos Archipelago in Guinea Bissau. Therefore the protection of these populations is crucial for the preservation and recovery of the species. Copyright © 2013 John Wiley & Sons, Ltd.

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2016-11-02T18:49:00

Given the conservation status and ecological, cultural, and commercial importance of chondrichthyan fishes, it is valuable to evaluate the extent to which research attention is spread across taxa and geographic locations and to assess the degree to which scientific research is appropriately addressing the challenges they face. Here we review trends in research effort over three decades (1985-2016) through content analysis of every abstract (n ¼ 2,701) presented at the annual conference of the American Elasmobranch Society (AES), the oldest and largest professional society focused on the scientific study and management of these fishes. The most common research areas of AES abstracts were reproductive biology, movement/telemetry, age and growth, population genetics, and diet/feeding ecology, with different areas of focus for different study species or families. The most commonly studied species were large and charismatic (e.g., White Shark, Carcharodon carcharias), easily accessible to long-term established field research programs (e.g., Lemon Shark, Negaprion brevirostris, and Sandbar Shark, Carcharhinus plumbeus), or easily kept in aquaria for lab-based research (e.g., Bonnethead Shark, Sphyrna tiburo). Nearly 90% of all described chondrichthyan species have never been mentioned in an AES abstract, including some of the most threatened species in the Americas. The proportion of female* first authors has increased over time, though many current female* Society members are graduate students. Nearly half of all research presented at AES occurred in the waters of the United States rather than in the waters of developing nations where there are more threatened species and few resources for research or management. Presentations based on research areas such as paleontology and aquarium-based research have declined in frequency over time, and identified research priorities such as social science and interdisciplinary research are poorly represented. Possible research gaps and future research priorities for the study of chondrichthyan fishes are also discussed.

Physiology and ecology are intimately linked; thus, ecological observations can be strengthened by an understanding of organismal physiology. Through a symposium entitled “Applications of Physiological Ecology in Elasmobranch Research” at the 2017 American Elasmobranch Society meeting, we demonstrated the strengths of collaborative efforts across disciplines for informing conservation efforts.

Fine-scale behavior of crocodilians has rarely been recorded in the field despite the important ecological roles these reptiles play in wetland systems around the world. In this study, we attached multi-sensor data loggers to freeranging American alligators Alligator mississippiensis in the northern Banana River Lagoon, Florida, to record their diving and swimming behavior, diel activity patterns, and horizontal movements. The alligators repeatedly showed shallow, inactive dives (mean depth: 0.75 m, duration: 310 s), which may represent sit-andwait foraging for prey. The alligators also showed periodic, submerged swimming events (mean duration: 59 s, swim speed: 0.31 m s −1 , tail-beat frequency: 0.47 Hz). Based on the occurrence of diving and swimming events, and the activity level inferred from acceleration records, the animals tended to be more active during the day than at night, suggesting behavioral thermoregulation. An individual with a global positioning system (GPS) logger attached swam northward along the shore, showing the utility of GPS tracking for this species. This study presents basic information for the natural behavior of croco dilians, an understudied group among aquatic vertebrates.KEY WORDS: Biologging · Crocodilian · Diving · Swimming · Alligator mississip piensis Resale or republication not permitted without written consent of the publisherAmerican alligator Alligator mississippiensis (length: 316 cm) equipped with a data logger package. Photo: Yuuki Watanabe OPEN PEN ACCESS CCESSAquat Biol 18: [1][2][3][4][5][6][7][8] 2013 studies are heavily biased toward mammals, birds, and fishes. With the exception of sea turtles (especially green Chelonia mydas, loggerhead Caretta caretta, and leatherback Dermochelys coriacea), reptiles and amphibians are under-studied and, hence, their behavior under natural conditions is not well known.Crocodilians are particularly under-studied, despite the fact that they play important roles in wetland ecosystems as top predators with a broad diet, creators of water pools that affect plant communities, and potential vectors of allochthonous nutrients (Craighead 1968, Bondavalli & Ulanowicz 1999, Rosenblatt & Heithaus 2011. Furthermore, some crocodilians are endangered due to past overharvesting and current habitat loss (Thorbjarnarson 1999, Thorbjarnarson & Wang 1999. At the same time, they can also pose a danger to humans (Langley 2005), and basic, ecological information is needed for effective management. Previous studies of free-ranging crocodilians have focused only on diving behavior detected by pressure sensors (Seebacher et al. 2005, Campbell et al. 2010a and large-scale (>10 km) horizontal movements detected by acoustic telemetry (Campbell et al. 2010c, Rosenblatt & Heithaus 2011 or satellite transmitters (Read et al. 2007). Franklin et al. (2009) applied various types of data loggers to crocodilians but presented only snapshots of several types of data they obtained. Therefore, daily activity patterns, which are basic information for the eco...