John T. Kelly

California Department of Fish and Wildlife | DFG

In spite of overall improvements in air and water quality, biological stress from low pH and high concentrations of inorganic aluminum continue to impact fish and fish habitat in northeastern North America, with independent and interactive effects on individuals, populations and communities. Integrative indicators can therefore be useful in monitor...

Understanding intraspecific variation in habitat use, particularly of long-lived fishes across multiple life history stages, is core to improved conservation management. Here, we present results from a synthesis of acoustic telemetry data for sub-adult and adult white sturgeon (Acipenser transmontanus) from 2010 to 2017 in the San Francisco Estuary...

The cost of osmoregulation in teleosts has been debated for decades, with estimates ranging from one to 30 % of routine metabolic rate. The variation in the energy budget appears to be greater for euryhaline fish due to their ability to withstand dynamic salinity levels. In this study, a time course of metabolic and physiological responses of the e...

Understanding movement patterns of anadromous fishes is critical to conservation and management of declining wild populations and preservation of habitats. Yet, the duration of observations for individual animals can constrain accurate descriptions of movements. In this study, we synthesized over a decade (2006–2018) of acoustic telemetry tracking...

Background Understanding movement patterns of anadromous fishes is critical to conservation management of declining wild populations and preservation of habitats. Yet, infrequent observations of individual animals fundamentally constrain accurate descriptions of movement dynamics. Methods In this study, we synthesized over a decade (2006–2018) of...

Sturgeon are fish that are considered living fossils. Their ancestors date back over 200 million years, to the same time as dinosaurs. These fish can grow taller than humans (over 2 m), weigh over 160 kg, and live as long as humans. Sturgeon species have special adaptations, such as a vacuum-like mouth and body armor called scutes. There are 27 spe...

As fish move, they incur an energetic cost of transport (COT) from the use of aerobic muscles. Water currents are an integral component of the physical world of fishes, and if water currents are present, fish may pay higher costs fighting the currents, or may use the currents to facilitate movement and reduce COT. Some fish use “selective tidal str...

Reversing global declines in the abundance and diversity of fishes is dependent on science-based conservation solutions. A wealth of data exist on the ecophysiological constraints of many fishes, but much of this information is underutilized in recovery plans due to a lack of synthesis. Here, we used the imperiled green sturgeon (Acipenser medirost...

Pupfishes (genus Cyprinodon) evolved some of the broadest salinity tolerances of teleost fishes, with some taxa surviving in conditions from freshwater to nearly 160 ppt. In this study, we examined transcriptional dynamics of ion transporters and aquaporins in the gill of the desert Amargosa pupfish (Cyprinodon nevadensis amargosae) during rapid sa...

Atlantic salmon (Salmo salar) smolts are sensitive to acid rain and associated increases in dissolved inorganic aluminum (Al) resulting in decreased seawater tolerance at this critical life stage. Salmon have two major isoforms of the catalytic alpha subunit of Na⁺/K⁺-ATPase (NKA), with NKAα1a being the major freshwater (FW) isoform and NKAα1b the...

Rheotropism (the ability to detect and respond to a current) and rheotaxis (deliberate orientation relative to a current) are widespread in fishes and aquatic organisms, but the relative importance of different sensory modalities as references for the rheotaxis response in fishes is largely unknown. While mechanical stimuli (including water flows)...

Field studies were conducted to determine levels of gill aluminium as an index of acidification effects on migrating Atlantic salmon Salmo salar smolts in the north-eastern U.S.A. along mainstem river migration corridors in several major river basins. Smolts emigrating from the Connecticut River, where most (but not all) tributaries were well buffe...

The use of internal telemetry has greatly advanced fisheries research in the past two decades, permitting researchers to observe movements and distributions of organisms in their natural environment. For many years, the prevailing opinion has been that internal tags should not weigh more than 2% of the dry body weight of a fish. Some studies indica...

Animals swimming in tidal environments continuously interact with water currents which may either hinder or aid their movement. It is difficult to observe the orientation of an organism relative to the current when it is swimming in the wild without specialized telemetry; however, using the total recorded movement vector and the current vector, one...

Green sturgeon Acipenser medirostris spend much of their lives outside of their natal rivers, but the details of their migrations and habitat use are poorly known, which limits our understanding of how this species might be affected by human activities and habitat degradation. We tagged 355 green sturgeon with acoustic transmitters on their spawnin...

Ultrasonic telemetry was used to analyze the effects of environmental variables on movement directions and movement rates of brown smoothhounds, Mustelus henlei, in Tomales Bay, California. Ultrasonic transmitters were surgically implanted in the peritoneal cavities of one male and five female brown smoothhounds and tracked during the period of 29...

Adult green sturgeon, Acipenser medirostris, were collected in San Pablo Bay, California, and surgically implanted with ultrasonic acoustic tags from 2004 to 2006. An array of automated acoustic monitors was maintained in the Sacramento River to record movements of these fish. We presumed movements to known spawning areas (based on previous green s...

Most anadromous fish undergo physiological and behavioral changes that are preparatory and adaptive for seawater entry. In anadromous salmonids, these preparatory changes are collectively known as smolting. Smolt development is regulated by environmental factors such as photoperiod and temperature and mediated by the neuroendocrine system. In this...

An understanding of the distribution of North American green sturgeon Acipenser medirostris in coastal waters is crucial to minimize impacts on this vulnerable species from various fisheries. To determine migratory patterns, we tagged 213 subadult and adult green sturgeon in spawning rivers and summer aggregation areas with uniquely coded ultrasoni...

The green sturgeon, Acipenser medirostris, is one of two acipenserid fishes native to the temperate waters of the Pacific coast of North America. Originally, three species of sturgeon were de- scribed from this region, and this one named ''medirostris'' or ''middle snout'' based on the length of its rostrum relative to the other purported species (...

The green sturgeon, Acipenser medirostris, is a long-lived, iteroparous, anadromous acipenserid that is native to the San Francisco Bay Estuary, California. Sub-adult and adult fish are oceanic, but enter the estuary during the spring and remain through autumn. Little is known about green sturgeon distribution within the estuary or what, if any, ph...

Scavenging of marine mammal carcasses is thought to be an important part of the diet of white sharks (Carcharodon carcharias), though scientific observations of this behavior are rare. A detailed analysis of this feeding behavior has not been previously reported, nor has it been compared with the documented predatory feeding habits of this species....

The goal of this project was to determine if bat rays, Myliobatis californica, display oriented movements and are thus a viable model species for the further study of geomagnetic topotaxis in elasmobranches. We tracked one male and three female rays during September 1998 and August and September 2001 in Tomales Bay, California. The rays exhibited t...

We present the results of a pilot study initiated during the fall of 2000 at the Point Reyes Headlands, a potential site for white shark research on the coast of California. The goal of this study was to determine if white sharks occur at this location. Ten sharks were observed during 45 h of sampling conducted between 9 October 2000, and 1 Februar...

The 2 interfaces of the aquatic environment, the boundary between air-water and water-substrate, have distinctive physical characteristics that facilitate the production of communication signals. Recent evidence suggests that animals living on or near these boundaries use the interface to generate signals in 2 ways: (a) by producing a signal that p...

The degree to which white sharks, Carcharodon carcharias, are social while hunting is unclear. Our aim was to describe the behavior and interactions among white sharks hunting seals near a seal colony. We attached ultrasonic beacons to five adult white sharks, 4.5–5.2 m long, and recorded their movements and behavior toward each other over a 15-day...