Nicholas Whitney

New England Aquarium · Anderson Cabot Center for Ocean Life

The practice of catch and release fishing is common among anglers but has been shown to cause unintended mortalities in some species. Current post-release mortality estimates used in coastal shark stock assessments are typically derived from boat-based shark fisheries, which differ from shore-based operations that expose sharks to potentially more...

Animals sometimes forage in mixed species groups, where an individual of a “follower” species actively trails a foraging individual of another “nuclear” species to benefit from the latter’s foraging strategy. Here, we report on a serendipitous observation of a large, benthic, reef-associated predator, the nurse shark ( G. cirratum ) following a pod...

Floating objects play a pivotal role in pelagic ecosystems by serving as shelters, meeting points, cleaning stations, nurseries, and feeding grounds. The abundance of these objects is increasing globally in the form of flotsam, plastics, discarded or lost fishing gear, and fish aggregating devices (FADs) deployed by commercial fisheries. However, i...

Understanding shark mating dynamics and mating site use may be vital to species management. The Dry Tortugas courtship and mating ground (DTCMG) has been known as a mating site for nurse sharks, Ginglymostoma cirratum, since 1895. In a 30-yr (1992-2021) study we have documented long-term site fidelity to this area with data from 137 adult sharks (8...

The post-release mortality (PRM) rate of sharks can be an important factor in estimating overall mortality in stock assessments. However, the accuracy of PRM rates is dependent on our ability to evaluate mortality under realistic fishing practices and conditions. In the Southeast U.S. recreational rod-and-reel fishery, we worked directly with recre...

Bycatch mortality is a major factor contributing to shark population declines. Post-release mortality (PRM) is particularly difficult to quantify, limiting the accuracy of stock assessments. We paired blood-stress physiology with animal-borne accelerometers to quantify PRM rates of sharks caught in a commercial bottom longline fishery. Blood was sa...

Niche partitioning of time, space or resources is considered the key to allowing the coexistence of competitor species, and particularly guilds of predators. However, the extent to which these processes occur in marine systems is poorly understood due to the difficulty in studying fine-scale movements and activity patterns in mobile underwater spec...

Dynamic Body Acceleration (DBA), measured through animal-attached tags, has emerged as a powerful method for estimating field metabolic rates of free-ranging individuals. Following respirometry to calibrate oxygen consumption rate ( M O 2 ) with DBA under controlled conditions, predictive models can be applied to DBA data collected from free-rangin...

Background The establishment of Burmese pythons ( Python bivittatus) in Everglades National Park, Florida, USA, has been connected to a > 90% decline in the mesomammal population in the park and is a major threat to native reptile and bird populations. Efforts to control this population are underway, but are hampered by a lack of information about...

Abstract Ocean warming and acidification act concurrently on marine ectotherms with the potential for detrimental, synergistic effects; yet, effects of these stressors remain understudied in large predatory fishes, including sharks. We tested for behavioural and physiological responses of blacktip reef shark (Carcharhinus melanopterus) neonates to...

In the coastal waters of the southeastern United States, the black-tip shark (Carcharhinus limbatus) is targeted by recreational anglers and is currently one of the most often captured large coastal shark species. We estimated postrelease mortality (PRM) rates for blacktip sharks captured on rod and reel by shore-based and charter-boat-based fisher...

Life history, reproduction, and survival are fundamentally linked to energy expenditure and acquisition. Dynamic Body Acceleration (DBA), measured through animal-attached data-loggers or transmitters, has emerged as a powerful method for estimating field metabolic rates of free-ranging individuals. After using respirometry to calibrate oxygen consu...

Environments where extreme temperatures and low productivity occur introduce energetically challenging circumstances that may be exacerbated by climate change. Despite the strong link between metabolism and temperature in ectotherms, there is a paucity of data regarding how the metabolic ecology of species affects growth and fitness under such circ...

Temperature is one of the most influential drivers of physiological performance and behaviour in ectotherms, determining how these animals relate to their ecosystems and their ability to succeed in particular habitats. Here, we analysed the largest set of acceleration data compiled to date for elasmobranchs to examine the relationship between volit...

Understanding the behaviours of free-ranging animals over biologically meaningful time scales (e.g., diel, tidal, lunar, seasonal, annual) gives unique insight into their ecology. Bio-logging tools such as accelerometers allow the remote study of elusive or inaccessible animals by recording high resolution movement data. Machine learning (ML) is be...

This study reports on the metabolic rate of the blacktip shark Carcharhinus limbatus and the energetic costs of external tag attachment. Metabolic rates, swimming speed and tail‐beat (BT) frequency were measured in a static respirometer with untagged animals and animals equipped with a small data logger. Tagged sharks showed significantly higher ro...

Nurse sharks have not previously been known to migrate. Nurse sharks of the Dry Tortugas (DRTO) mating population have a highly predictable periodic residency cycle, returning to the Dry Tortugas Courtship and Mating Ground (DTCMG) annually (males) or bi- to triennially (females) during the June/July mating season. For 23 years we have followed the...

Discerning behaviours of free-ranging animals allows for quantifcation of their activity budget, providing important insight into ecology. Over recent years, accelerometers have been used to unveil the cryptic lives of animals. The increased ability of accelerometers to store large quantities of high resolution data has prompted a need for automate...

Measuring the metabolic rate of animals is an essential part of understanding their ecology, behaviour and life history. Respirometry is the standard method of measuring metabolism in fish, but different respirometry methods and systems can result in disparate measurements of metabolic rate, a factor often difficult to quantify. Here we directly co...

The blacktip shark (Carcharhinus limbatus) is the most commonly captured species in the Florida recreational shark fishery. We aimed to quantify the postrelease mortality of blacktip sharks and to determine whether hook type (circle or J) had any impact on survival. We measured capture variables (e.g., fight time, animal condition, etc.), blood gas...

The ability to produce estimates of the metabolic rate of free-ranging animals is fundamental to the study of their ecology. However, measuring the energy expenditure of animals in the field has proven difficult, especially for aquatic taxa. Accelerometry presents a means of translating metabolic rates measured in the laboratory to individuals stud...

To better protect endangered green sea turtles Chelonia mydas, a more thorough understanding of the behaviors of each life stage is needed. Although dive profile analyses obtained using time-depth loggers have provided some insights into habitat use, recent work has shown that more fine-scale monitoring of body movements is needed to elucidate phys...

Dolphinfish (Coryphaena hippurus), large pelagic predators and important fishery targets, frequently associate with floating debris or manmade fish aggregating devices (FADs). We tagged 8 dolphinfish with pressure-sensitive ultrasonic transmitters and actively tracked individuals continuously for up to 40 h to elucidate the vertical movement patter...

Background Despite the utility of data loggers for studying the fine-scale behavior and energetics of marine organisms, most studies using these tools have had relatively low sample sizes due to various factors including the logistical difficulty of physically recovering the loggers. Here, we report a simple methodology for recovering large numbers...

Sharks and other top predators have a substantial impact on their ecosystems through trophically mediated effects, and understanding the scope of this impact is essential to forming an accurate picture of energy flow within an ecosystem. One of the most important factors to consider when assessing a predator's impact on their ecosystem is metabolic...

Conservation of ecological communities requires deepening our understanding of genetic diversity patterns and drivers at community-wide scales. Here, we use seascape genetic analysis of a diversity metric, allelic richness (AR), for 47 reef species sampled across 13 Hawaiian Islands to empirically demonstrate that large reefs high in coral cover ha...

Synopsis Animal navigation in the marine environment is believed to be guided by different sensory cues over different spatial scales. Geomagnetic cues are thought to guide long-range navigation, while visual or olfactory cues allow animals to pinpoint precise locations, but the complete behavioral sequence is not yet understood. Terra Ceia Bay is...

Many sturgeon species jump, and proposed reasons for jumping have included the removal of parasites, signaling as part of nuptial behavior, to help shed eggs during spawning, or as a form of communication to maintain group cohesion. These ideas have been difficult to test, in part because of an inability to monitor the fine-scale behavior of indivi...

Sharks exhibit a broad range of reproductive strategies that often include complex behaviors and varying levels of multiple paternity within broods. Understanding these strategies is important for conservation and management, it is inherently difficult to measure the behavioral and physiological forces driving each strategy. We used acceleration da...

Despite being a common apex-level predator on coral reefs throughout the tropical Indo-Pacific, surprisingly little is known about whitetip reef shark (Triaenodon obesus) movements and biology. This study used photo-identification from community-contributed photographs to reveal patterns in movements, reproductive biology, and fisheries interaction...

Aim - Most reef fishes are site-attached, but can maintain a broad distribution through their highly dispersive larval stage. The whitetip reef shark (Triaenodon obesus) is site-attached, yet maintains the largest Indo-Pacific distribution of any reef shark while lacking the larval stage of bony (teleost) fishes. Here we use mitochondrial DNA (mtDN...

In the face of the physical and physiological challenges of performing breath-hold deep dives, marine vertebrates have evolved different strategies. Although behavioural strategies in marine mammals and seabirds have been investigated in detail, little is known about the deepest-diving reptile - the leatherback turtle (Dermochelys coriacea). Here,...

Little is known about the reproductive strategies and mating behaviour of most sharks. Understanding mating behaviour is important as it can determine reproductive success and possibly rates of multiple paternity and fecundity. Additionally, some sharks appear to have specific habitat requirements for mating activities. We tested the utility of a 3...

Shark cage diving is both popular and controversial, with proponents citing educational value and non-extractive use of natural resources and opponents raising concerns about public safety and ecological impacts. Logbook data collected 2004-2008 from two Oahu (Hawaii) shark cage diving operations were analysed to determine whether such voluntary re...

Little is known about the long-term movement patterns of most marine apex predators. A network of acoustic receivers was used to quantify the long-term movements of transmitter-equipped tiger sharks Galeocerdo cuvier Peron & Lesueur, 1822 in the Main Hawaiian Islands. Tiger sharks were wide-ranging, swam between islands and patrolled up to 109 km o...

Traditional telemetry methods have been used to quantify the horizontal and vertical displacement of marine species, but are unable to identify specific physical activities such as swimming or gliding, resting, foraging, or spawning. We tested the utility of an acceleration data logger to quantify activity patterns of three captive whitetip reef sh...

The tiger shark (Galeocerdo cuvier) is the largest shark in the family Carcharhinidae and the only carcharhinid with aplacental viviparous (ovoviviparous) reproduction. Despite its size and prevalence, many details of tiger shark reproductive biology are unknown. Size at maturity and litter size have been reported by several authors, but a lack of...

We analysed video records of three mating events involving nine free-living whitetip reef sharks in Cocos Islands, Costa Rica to examine reproductive behaviour in this species. We describe several behaviours never before documented in this species, and four behaviours never before documented in any elasmobranch. Here, we also present the first hypo...