John Mandelman

New England Aquarium

Body condition is an important proxy for the overall health and energetic status of fishes. The classically used Fulton's condition factor requires length and mass measurements, but mass can be difficult to obtain in large species. Girth measurements can replace mass for wild pelagic sharks. However, girth‐calculated condition has not been validate...

Owing to climate change, most notably the increasing frequency of marine heatwaves and long-term ocean warming, better elucidating the upper thermal limits of marine fishes is important for predicting the future of species and populations. The critical thermal maximum (CTmax), or the highest temperature a species can tolerate, is a physiological me...

Epaulette sharks ( Hemiscyllium ocellatum ) inhabit shallow tropical habitats with elevated and fluctuating temperatures. Yet, according to global climate change projections, water temperatures in these habitats will rise beyond current cyclical variability, warranting further studies incorporating chronically elevated temperature exposure in this...

Biological rhythms that are mediated by exogenous factors, such as light and temperature, drive the physiology of organisms and affect processes ranging from cellular to population levels. For elasmobranchs (i.e. sharks, rays, and skates), studies documenting diel activity and movement patterns indicate that many species are crepuscular or nocturna...

Recent work in the Gulf of Maine multispecies recreational fishery has established responsible fishing practices that anglers can use to reduce bycatch and the discard mortality of three key groundfish species. However, anglers represent a diverse stakeholder group whose backgrounds and experiences may influence how they receive, support, and adopt...

Discard mortality studies are considered a primary research priority, particularly for species and fisheries where discard rates are high. Monkfish (the commercial name for Goosefish) Lophius americanus supports the most lucrative finfish fishery in New England, and it is also the second highest bycatch species by weight in the sea scallop dredge f...

Environmental change and biodiversity loss are but two of the complex challenges facing conservation practitioners and policy makers. Relevant and robust scientific knowledge is critical for providing decision-makers with the actionable evidence needed to inform conservation decisions. In the Anthropocene, science that leads to meaningful improveme...

Terminal tackle regulations can be a valuable tool for fisheries management, especially in multispecies fisheries where bycatch and discards are common issues. In the Gulf of Maine, recreational anglers frequently discard critically depleted Atlantic cod Gadus morhua L. as bycatch when targeting the abundant haddock Melanogrammus aeglefinus (L.) st...

The Atlantic sea scallop Placopecten magellanicus dredge fishery is one of the most lucrative commercial fishing industries in the northeastern United States, and fish bycatch can comprise up to~42% of the total catch. Benthic species , such as flatfish, are particularly susceptible to unintended capture in scallop dredge gear, and mitigating bycat...

Climate change is affecting thermal regimes globally, and organisms relying on their environment to regulate biological processes face unknown consequences. In ectotherms, temperature affects development rates, body condition, and performance. Embryonic stages may be the most vulnerable life history stages, especially for oviparous species already...

Thorny skate (Amblyraja radiata) have experienced decreasing abundance and range contraction in the Gulf of Maine (GOM) in recent decades. To better understand the extent to which population structure, environmental conditions, and movement ecology may play a role in these disruptions, 128 “mark-report” pop-up satellite tags (mrPATs) and 2195 conve...

Fishes are often caught as bycatch on longlines and subsequently discarded. The behavioural response of fishes to longline capture is poorly understood, although it may be linked to the magnitude of the physiological stress response, and, ultimately, contribute to stress-induced mortality. We used accelerometers, video cameras, and hook timers to a...

The Gulf of Maine (GOM) commercial lobster fishery has approximately 3.5 million actively fished traps and captures several non‐targeted groundfish species, including Atlantic Cod Gadus morhua (hereafter “cod”) as bycatch; yet, there has been limited research on the incidental mortality of these species in this fishery. While the mortality of cod h...

The consequences of human influence can arise in vertebrates as primary, secondary, or even tertiary stressors and may be especially detrimental for slow growing species with long generation times (i.e., K-selected species). Here, we review the impacts of both direct and indirect human interactions on the reproductive biology of elasmobranchs. With...

The effects of barotrauma and other capture-related factors on the discard mortality of black sea bass (Centropristis striata) are poorly understood. The objective of this study was to estimate the discard mortality rate for black sea bass in the winter deepwa-ter recreational fishery off New Jersey and to evaluate if swim bladder venting can reduc...

Applying physiological tools, knowledge and concepts to understand conservation problems (i.e. conservation physiology) has become commonplace and confers an ability to understand mechanistic processes, develop predictive models and identify cause-and-effect relationships. Conservation physiology is making contributions to conservation solutions; t...

This study assessed the in vitro temporal changes that occur in blood pH and lactate concentrations for an elasmobranch species and a chelonian species, as well as blood gases (partial pressures of carbon dioxide [pCO2] and oxygen [pO2]) for a chelonian species, with a portable clinical point-of-care analyzer. Blood samples were collected from 10 c...

The purpose of this study was to test the effects of high CO2 exposure on wound healing rates in an elasmobranch fish (Urobatis jamaicensis). Small dermal injuries (8 mm biopsy) closed by 22 days post wounding with a decrease in haematocrit. High CO2 exposure (ΔpH = 1.4) did not influence healing rate or haematocrit. Combined, these data provide ev...

Studying the species-specific responses to fishing capture is critical for effective management and conservation of bycatch species given that acute stress incurred from capture and handling may ultimately lead to mortality. While species of low commercial value are often overlooked, having accurate information on the effects of capture on all spec...

Information on elasmobranch mating behavior is limited. For batoids, observations of mating behavior in the wild are available only for a few species. We present video documentation of new cases of mating behavior for three species of myliobatiform rays. On July 20, 2013, a group of six cownose rays (Rhinoptera bonasus) were observed mating in shal...

[This corrects the article DOI: 10.1093/conphys/coz042.].

Utilization of pop-up satellite archival transmitting tags to evaluate thorny skate (Amblyraja radiata) discard mortality in the Gulf of Maine groundfish bottom trawl fishery. Thorny skate (Amblyraja radiata) remain one of the most overfished species in the Gulf of Maine (GOM) despite being designated as a prohibited (zero-possession, mandatory rel...

Thorny skate (Amblyraja radiata) remain one of the most overfished species in the Gulf of Maine (GOM) despite being designated as a prohibited (zero-possession, mandatory release) species by the New England Fishery Management Council in 2003. To better understand the extent to which discard mortality (DM) occurring after incidental capture in the G...

Drumlines incorporating SMART (Shark-Management-Alert-in-Real-Time) technology are a new tool used in several bather protection programmes globally. In New South Wales (NSW), Australia, the white shark (Carcharodon carcharias) is a target species for SMART drumlines because they are often involved in attacks on humans. To understand white shark sen...

Empirical discard mortality rate estimates are vital to both stock assessments and fishery management, especially for stocks that experience high discard rates, such as in the recreational rod‐and‐reel fishery for Haddock Melanogrammus aeglefinus in the Gulf of Maine. The objective of the present study was to derive a fishery‐scale discard mortalit...

The hypothalamic‐pituitary‐interrenal (HPI) or stress axis in teleost fishes produces their primary glucocorticoid, cortisol. Although generally an adaptive response, prolonged HPI axis stimulation can impair organismal performance. Previous work has shown that stressed teleosts have higher mortality to predation than unstressed conspecifics, sugge...

Some shark populations face declines owing to targeted capture and by-catch in longline fisheries. Exercise intensity during longline capture and physiological status may be associated, which could inform management strategies aimed at reducing the impacts of longline capture on sharks. The purpose of this study was to characterize relationships be...

Capture and handling stress studies are considered a primary research priority, particularly for species and fisheries where discard rates are high, and/or for overfished stocks and species of concern. Lophius americanus, a commercially valuable finfish in New England, constitutes the second highest bycatch species within the sea scallop dredge fis...

Black sea bass (BSB) (Centropristis striata) migrate seasonally to overwinter near the continental shelf edge. Recreational anglers often discard BSB during the winter, but the discard mortality (DM) rate in this fishery was unknown. We estimated the BSB DM rate for the winter fishery, identified factors that significantly influence DM, and derived...

Knowing how often animals engage in different behaviors and their energetic costs may explain why animals behave the way they do in the wild. This study sought to investigate the relationship between the frequency of various swimming behaviors and their associated energetic costs (oxygen consumption rates) in situ for juvenile lemon sharks (Negapri...

Bycatch interactions with deep-sea elasmobranchs are increasingly common and can lead to dramatic declines in abundance over short time scales. Sharks hooked in the deep sea could face a higher likelihood of severe physiological disturbance, at-vessel mortality, and postrelease mortality (PRM) than their shallower counterparts. Unfortunately, robus...

Due primarily to regulatory factors, skates (family Rajidae) account for nearly half the total bycatch discarded during commercial fishing operations in the U.S. portion of the Northwest Atlantic Ocean. In this region the New England scallop dredge fishery has the second highest skate discard rate; however, no information regarding their resiliency...

The stress axis in teleost fish attempts to maintain internal homeostasis in the face of allostatic loading. However, stress axis induction has been associated with a higher predation rate in fish. To date, the physiological and behavioural factors associated with this outcome are poorly understood. The purpose of the present study was to investiga...

Discard mortality (DM) estimates are vitally important to fisheries management. Commercial fishery DM estimates, for example, can help calculate total fishing mortality and biologically acceptable catch limits. The winter skate, Leucoraja ocellata, is the only species within the US portion of the western North Atlantic that is targeted in the skate...

Quantifying changes in blood chemistry in elasmobranchs can provide insights into the physiological insults caused by anthropogenic stress, and can ultimately inform conservation and management strategies. Current methods for analysing elasmobranch blood chemistry in the field are often costly and logistically challenging. We compared blood pH valu...

The hypothalamic-pituitary-interrenal (HPI) axis, through corticosteroid secretion, is an integral mechanism regulating internal homeostasis when vertebrates are faced with a stressor. However, continued HPI-axis stimulation can produce homeostatic overload, where corticosteroids are detrimental to organismal function. This overload condition may p...

This study sought to observe the effects of submerged weight and frontal cross-sectional area of external telemetry packages on the kinematics, activity levels and swimming performance of small-bodied juvenile sharks, using lemon sharks Negaprion brevirostris (60-80 cm total length, LT ) as a model species. Juveniles were observed free-swimming in...

There is much interest in being able to quantify the swimming speeds and metabolic rates of wild aquatic animals such as sharks to develop bioenergetics models and evaluate the metabolic consequences of different stressors. This study sought to calibrate tri-axial acceleration biologgers (accelerometers) such that it would be possible to estimate s...

Supplemental material

Supplemental material

Commercial fisheries are recognized as one of the greatest threats to shark populations worldwide, but factors affecting the likelihood of shark mortality during fishery capture are poorly understood. We used the U.S. pelagic fishery logbook data from 1992 through 2008 to quantify the effects of several variables (fisheries regulatory periods, geog...

Carcharhinus plumbeus (sandbar shark) and C. obscurus (dusky shark) occur in many global fisheries. However, little is known about their movement and the possible fate of discards. We redressed this lack of knowledge using pop-up satellite archival tags (PSAT) and acoustic tagging technologies. Eight sharks of each species were caught by demersal l...

Open access link: http://icesjms.oxfordjournals.org/cgi/reprint/fsw058?ijkey=BuTWCAewKazxV4l&keytype=ref In recent years, the recreational contribution to the total catch of Atlantic cod (Gadus morhua) in the Gulf of Maine (GOM) has increased with recreational discards outnumbering recreational landings by 2:1. However, the discard mortality (DM...

With the increasing popularity of recreational angling around the world, there is a need to better understand the potential contribution of recreational fishing to reported shark population declines. However, the nature and perception of shark encounters – a fundamental precursor to future research, management and conservation measures aimed to inc...

The post-release mortality of discarded fish can represent an additional source of mortality that is important to understand for effective marine fisheries management. To best estimate these mortality rates under near-natural conditions, a refrigerated flow-through seawater system was developed for short-term holding experiments at-sea aboard comme...

The Gulf of Maine recreational groundfish fishery, which primarily targets cod and haddock, is managed using a bio-economic model that is sensitive to estimates of discard mortality. When determining fishery management measures, the stock size and discard mortality estimates for one species influence the management of the other. Therefore, reliable...

This study investigates mortality of sharks in a commercial longline fishery in Australia. To examine the rate and biological, environmental and technological factors contributing to at-vessel mortality, four setlines with 120 gangions possessing ‘hook timers’ were deployed daily (for 7h and 14h) using conventional gears from two commercial fishing...

Conservation concerns and new management policies such as the implementation of ecosystem-based approaches to fisheries management are motivating an increasing need for estimates of mortality associated with commercial fishery discards and released fish from recreational fisheries. Traditional containment studies and emerging techniques using elect...

Conservation concerns and new management policies such as the implementation of ecosystem-based approaches to fisheries management are motivating an increasing need for estimates of mortality associated with commercial fishery discards and released fish from recreational fisheries. Traditional containment studies and emerging techniques using elect...

Accurate measurements of blood gases and acid–base status require an array of sophisticated laboratory equipment that is typically not available during field research; such is the case for many studies on the stress physiology, ecology and conservation of elasmobranch fish species. Consequently, researchers have adopted portable clinical analysers...

Few data are available on interspecific elasmobranch interactions during predation events. This report describes and discusses empirical data from a single event in which four sharks (species: Carcharhinus leucas, Galeocerdo cuvier, Sphyrna mokarran and Carcharhinus perezi) competed for foraging opportunities on a fifth shark (C. perezi) caught on...

Recreational hook-and-line angling for Atlantic cod, Gadus morhua, in the Gulf of Maine (GOM) has increased over the past decade and recreational discards are currently approximately double the recreational landings in this region. However, the post-release mortality (PRM) of cod remains poorly understood, creating uncertainty in GOM cod stock asse...

Recreational hook-and-line angling for Atlantic cod, Gadus morhua, in the Gulf of Maine (GOM) has increased over the past decade and recreational discards are approximately double the recreational landings in this region. However, the discard mortality of cod remains poorly understood, creating uncertainty in recent GOM cod stock assessments. The c...

Due to high commercial and recreational discard rates, post-release mortality (PRM) estimates are direly important to fisheries management and conservation. Among other functions, PRM estimates are utilized in stock assessments, setting allowable catch limits, and establishing accountability measures for a fishery. Studies estimating PRM can also i...

Due primarily to regulatory factors, skates (family Rajidae) account for nearly half the total bycatch discarded during commercial fishing operations in the U.S. portion of the Northwest Atlantic Ocean. Although the New England scallop dredge fishery has the second highest skate discard rate, no information regarding their resiliency to interaction...

Sport fishing for sharks, including fishing with the intent to release, is becoming more prevalent within the recreational angling community. Common targets of recreational anglers are juvenile lemon sharks (Negaprion brevirostris) that frequent shallow tropical nearshore habitats. In this study, we captured 32 juvenile lemon sharks (530–875 mm tot...

Non-human vertebrate blood is commonly collected and assayed for a variety of applications, including veterinary diagnostics and physiological research. Small, often non-lethal samples enable the assessment and monitoring of the physiological state and health of the individual. Traditionally, studies that rely on blood physiology have focused on ca...

Sport fishing for sharks, including fishing with the intent to release, is becoming more prevalent within the recreational angling community. Common targets of recreational anglers are juvenile lemon sharks (Negaprion brevirostris) that frequent shallow tropical nearshore habitats. In this study, we captured 32 juvenile lemon sharks (530–875 mm tot...

Due primarily to regulatory factors, skates from the family Rajidae account for nearly half the total bycatch discarded during commercial fishing operations in the U.S. portion of the Northwest Atlantic Ocean. However, despite the rigors of capture and handling, and mounting management and conservation concerns, few studies have investigated the po...

Incidental capture, or bycatch, in fisheries represents a substantial threat to the sustainability of elasmobranch populations worldwide. Consequently, researchers are increasingly investigating elasmobranch bycatch reduction methods, including some focused on these species' sensory capabilities, particularly their electrosensory systems. To guide...

Due to market and regulatory factors, Rajidae skates are routinely discarded by commercial otter trawlers in the western North Atlantic. Accounting for post-release mortality is therefore essential to total fishing mortality estimates, stock status and management of this group of fishes. However, despite a presumed species-specific range in toleran...

Common haematological [haematocrit (Hct)], primary (serum cortisol) and secondary (serum glucose and plasma lactate) analytes were utilized to compare blood biochemical status of Gadus morhua captured rapidly by jig with that of G. morhua captured by commercial demersal longline. In general, the physiological status of G. morhua, despite blind hook...

Targeting sharks with hook and line angling is becoming more prevalent within the recreational angling community. Although catch-and-release is often advocated as a conservation measure for protecting these apex predators, little research has been conducted to quantify the effects of catch-and-release angling on sharks. Juvenile lemon sharks (Negap...

The health, postrelease movements, and behavior of mass stranded Atlantic white-sided dolphins (Lagenorhynchus acutus) and short-beaked common dolphins (Delphinus delphis) from Cape Cod, Massachusetts, were evaluated. Health was assessed through physical examination and blood analysis. Eleven dolphins (eight white-sided dolphins and three common do...