Jacob L Johansen

Jacob L Johansen
University of Hawaiʻi at Mānoa | UH Manoa · "Hawaii Institute of Marine Biology"

PhD

About

74
Publications
15,251
Reads
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1,728
Citations
Introduction
Work interests: 1) Resilience of fish and fisheries to environmental changes and extreme conditions 2) Coral reef ecology 3) Fish habitat requirements 4) Physiological and behavioural plasticity 5) Respiratory physiology and Eco-morphology 5) Field surveys (SCUBA/remote tracking) 6) Impact of catchment run-off, pollution and climate change on coastal and benthic ecosystems, particularly ecologically and commercially important species. I am available for Research, Consultancy and Teaching
Additional affiliations
September 2012 - present
ARC Centre of Excellence for Coral Reef Studies
Position
  • Resilience of Coral Trout (Plectropomus leopardus) to global warming
Description
  • In this project I investigate the physiological and ecological resilience of Coral Trout to global warming. This species constitute one of the most important fisheries in the South-East Pacific
August 2012 - present
Reef Ecotours
Position
  • Marine Scientist -teaching
Description
  • I conduct 5-7 day educational field trips to the Great Barrier Reef for school groups and university students. I teach Coral Reef Ecology.
May 2012 - July 2012
Sea Research
Position
  • Marine Scientist -Consultancy
Description
  • As a consultant, I help conduct Environmental Impact Assessments for Coal-Mine Port Developments in Coral Reef environments. I can assess biodiversity of fish, coral and benthos + ecosystem health and its ability to withstand industrial development.
Education
October 2007 - October 2012
James Cook University
Field of study
  • Marine Biology, Coral Reef Ecoology, Fish Physiology

Publications

Publications (74)
Article
Fish perform rapid escape responses to avoid sudden predatory attacks. During escape responses, fish bend their bodies into a C-shape and quickly turn away from the predator and accelerate. The escape trajectory is determined by the initial turn (Stage 1) and a contralateral bend (Stage 2). Previous studies have used a single threat or model predat...
Preprint
Full-text available
Fish perform rapid escape responses to avoid sudden predatory attacks. During escape responses, fish bend their bodies into a C-shape and quickly turn away from the predator and accelerate. The escape trajectory is determined by the initial turn (Stage 1) and a contralateral bend (Stage 2). Previous studies have used a single threat or model predat...
Article
Full-text available
Using social groups (i.e. schools) of the tropical damselfish Chromis viridis, we test how familiarity through repeated social interactions influences fast-start responses, the primary defensive behaviour in a range of taxa, including fish, sharks, and larval amphibians. We focus on reactivity through response latency and kinematic performance (i.e...
Article
Full-text available
Increasing ocean temperatures and the resulting poleward range shifts of species has highlighted the importance of a species preferred temperature and thermal range in shaping ecological communities. Understanding the temperatures preferred and avoided by individual species, and how these are influenced by species interactions is critical in predic...
Article
Full-text available
As climate-driven heat waves become more frequent and intense, there is increasing urgency to understand how thermally sensitive species are responding. Acute heating events lasting days to months may elicit acclimation responses to improve performance and survival. However, the coordination of acclimation responses remains largely unknown for most...
Experiment Findings
Full-text available
List of published research projects, all run and completed during the FHL Fish Swim course.
Article
Full-text available
Fast escape responses to a predator threat are fundamental to the survival of mobile marine organisms. However, elasmobranchs are often underrepresented in such studies. Here, we measured the escape latency (time interval between the stimulus and first visible reaction) of mechanically-induced escape responses in the Pacific spiny dogfish, Squalus...
Article
Highly variable thermal environments, such as coral reef flats, are challenging for marine ectotherms, and are thought to invoke the use of behavioural strategies to avoid extreme temperatures and seek out thermal environments close to their preferred temperatures. Common to coral reef flats, the epaulette shark (Hemiscyllium ocellatum) possesses p...
Article
Full-text available
Wave-induced surge conditions are found in shallow marine ecosystems worldwide; yet, few studies have quantified how cyclical surges may affect free swimming animals. Here, we used a recently adapted respirometry technique to compare the energetic costs of a temperate fish species (Cymatogaster aggregata) swimming against a steady flow versus cycli...
Article
Full-text available
Coral reef species, like most tropical species, are sensitive to increasing environmental temperatures, with many species already living close to their thermal maxima. Ocean warming and the increasing frequency and intensity of marine heatwaves are challenging the persistence of reef-associated species through both direct physiological effects of e...
Article
Crude oil is a well-known toxicant that reduces cardiorespiratory performance in acutely exposed fishes. While toxic effects can manifest in death in severe cases, the ecological consequences of sub-lethal exposure remain uncertain. This study investigated the impact of crude oil exposure on long-term social competition, growth, and metabolic perfo...
Article
Full-text available
Tropical ectotherms are hypothesized to be vulnerable to environmental changes, but cascading effects of organismal tolerances on the assembly and functioning of reef fish communities are largely unknown. Here, we examine differences in organismal traits, assemblage structure, and productivity of cryptobenthic reef fishes between the world’s hottes...
Article
To forage in fast, turbulent flow environments where prey is abundant, fishes must deal with the high associated costs of locomotion. Prevailing theory suggests that many species exploit hydrodynamic refuges to minimize the cost of locomotion while foraging. Here, we challenge this theory based on direct oxygen consumption measurements of drift-fee...
Article
Full-text available
Coral reefs are one of the most biodiverse and economically important ecosystems in the world, but they are rapidly degrading due to the effects of global climate change and local anthropogenic stressors. Reef scientists are increasingly studying coral reefs that occur in marginal and extreme environments to understand how organisms respond to, and...
Preprint
Full-text available
To forage in fast, turbulent flow environments where prey are abundant, predatory fishes must deal with the high associated costs of locomotion. Prevailing theory suggests that many species exploit hydrodynamic refuges to minimize the cost of locomotion while foraging. Here we challenge this theory based on direct oxygen consumption measurements of...
Article
A predator’s ability to capture prey depends critically on how it coordinates its approach in response to a prey’s motion. Flying insects, bats and raptors are capable of capturing prey with a strategy known as parallel navigation, which allows a predator to move directly towards the anticipated point of interception. It is unclear if predators usi...
Article
Acute exposure to crude oil and polycyclic aromatic hydrocarbons (PAH) can severely impair cardiorespiratory function and swim performance of larval, juvenile and adult fish. Interestingly, recent work has documented an oil induced decoupling of swim performance (U crit ) and maximum metabolic rate (MMR) whereby oil causes a decline in U crit witho...
Article
The 2010 Deepwater Horizon (DWH) oil spill in the Gulf of Mexico was the largest spill in recent history and led to the exposure of many commercially and ecologically important fish species. Crude-oil exposure is known to result in compromised cardiorespiratory function and swim performance of fishes, presumably altering ecological performance by i...
Article
This study investigated the oxygen consumption of the putative oxygen conformer marbled swamp eel Synbranchus marmoratus during progressive hypoxia. Earlier studies have not reached agreement on whether S. marmoratus is a conformer or regulator. Our results support the view that S. marmoratus is an oxygen regulator, like most bony fishes. This arti...
Article
Full-text available
Tropical coral reef flats can be 3–4 °C warmer than surrounding deeper reef slopes, and some experience daily temperature fluctuations of up to 12 °C, which will be exacerbated as global temperatures continue to rise. Epaulette sharks (Hemiscyllium ocellatum), predominantly found on reef flats, may have evolved behavioural and/or physiological stra...
Chapter
Anthropogenically sourced chemicals are commonly released into aquatic habitats where they can have a multitude of detrimental effects on organisms and ecosystems. Aquatic toxicants typically exert impacts through perturbation of physiological function; however, these effects can vary greatly depending on the life stage and environment of the organ...
Article
The present study examined impacts of crude oil exposure on dyad competition in juvenile red drum. Following the 2010 Deepwater Horizon oil spill, it has become well established that oil exposure can constrain maximum metabolic rate, reduce aerobic scope and exercise performance in marine fish. Aerobic scope is one of the physiological characterist...
Article
Full-text available
Fish swimming energetics are often measured in laboratory environments which attempt to minimize turbulence, though turbulent flows are common in the natural environment. To test whether the swimming energetics and kinematics of shiner perchCymatogaster aggregata(a labriform swimmer) were affected by turbulence, two flow conditions were constructed...
Article
The Gulf of Mexico was home to the Deepwater Horizon oil spill, and is also known to exhibit seasonal declines in oxygen availability. Oil exposure in fish is known to impact oxygen uptake through cardiac impairment, which raises questions about the additive effects of these two stressors. Here we explore this question on the Atlantic croaker using...
Presentation
Fast-start escape responses are used by fish when dealing with predatory threats that require a quick response with high velocity. Recent work on archerfish has suggested that the kinematics of a fast start towards a prey is similar to that of escape response from a threat. Here we test the hypothesis that untrained predatory fish would respond to...
Article
Full-text available
To date, more than 81 species of tropical coral reef fish have been reported to hybridize in nature, spanning multiple families, including the Chaetodontidae, Pomacanthidae, and Labridae. Hybridization, however, is seemingly rare among benthic nesting species that engage in pair spawning, such as the Pomacentridae. Here, we present evidence for the...
Article
In the version of this Article originally published, a statistic relating to the northern Great Barrier Reef was attributed to the Great Barrier Reef as a whole. The sentence should have read ‘In 2016 alone, more than 35% of corals on the northern Great Barrier Reef are estimated to have died following the worst bleaching event ever recorded’. This...
Article
Global demand for energy and oil-based products is progressively introducing petrogenic polycyclic aromatic hydrocarbons (PAHs) into sensitive marine environments, primarily from fossil-fuel exploration, transport, and urban and industrial runoff. These toxic pollutants are found worldwide, yet the long-term ecological effects on coral reef ecosyst...
Article
Full-text available
Rising ocean temperatures are predicted to cause a poleward shift in the distribution of marine fishes occupying the extent of latitudes tolerable within their thermal range boundaries. A prevailing theory suggests that the upper thermal limits of fishes are constrained by hypoxia and ocean acidification. However, some eurythermal fish species do n...
Article
Acute exposure to crude oil polycyclic aromatic hydrocarbons (PAH) can severely impair cardiorespiratory function and swim performance of larval fish; however, the effects of acute oil exposure on later life stages and the capacity for subsequent recovery is less clear. Red drum (Sciaenops ocellatus) is an economically important apex predator nativ...
Article
Full-text available
The effect of the presence and angular position of a refuge on the direction and kinematics of mechanically-induced escape responses was observed in staghorn sculpins Leptocottus armatus using high-speed video. The results showed that the angular position of the refuge did not affect locomotor performance (speed and acceleration), although it did a...
Article
Experiments on the flow-sensitive lateral line system of fishes have provided important insights into the function and sensory transduction of vertebrate hair cells. A common experimental approach has been to pharmacologically block lateral line hair cells and measure how behavior changes. Cobalt chloride (CoCl2) blocks the lateral line by inhibiti...
Article
This study examined thermally driven changes in swimming performance and aerobic metabolism (Q10 and aerobic scope of activity) of adult King George whiting Sillaginodes punctatus to the coldest (16° C) and the warmest (26° C) temperature encountered by this species. Compensation of aerobic scope, higher maximal swimming speeds and a maintained cap...
Article
Full-text available
Previous studies hailed thermal tolerance and the capacity for organisms to acclimate and adapt as the primary pathways for species survival under climate change. Here we challenge this theory. Over the past decade more than 365 tropical stenothermal fish species have been documented moving pole-ward, away from ocean warming hotspots where temperat...
Article
Full-text available
Climate change is one of the greatest threats to the persistence of coral reefs. Sustained and ongoing increases in ocean temperatures and acidification are altering the structure and function of reefs globally. Here, we summarise recent advances in our understanding of the effects of climate change on scleractinian corals and reef fish. Although t...
Article
Full-text available
The impacts of human activities on the natural world are becoming increasingly apparent, with rapid development and exploitation occurring at the expense of habitat quality and biodiversity. Declines are especially concerning in the oceans, which hold intrinsic value due to their biological uniqueness as well as their substantial sociological and e...
Article
Full-text available
Respirometry is frequently used to estimate metabolic rates and examine organismal responses to environmental change. Although a range of methodologies exists, it remains unclear whether differences in chamber design and exercise (type and duration) produce comparable results within individuals and whether the most appropriate method differs across...
Article
Full-text available
This study compares the critical oxygen saturation (O2crit) levels of the shiner perch Cymatogaster aggregata obtained using two different methods wherein hypoxia is induced either by the fish's respiration (closed respirometry) or by degassing oxygen with nitrogen (intermittent-flow respirometry). Fish exhibited loss of equilibrium at a higher O2...
Article
Full-text available
Prey individuals with complex life-histories often cannot predict the type of risk environment to which they will be exposed at each of their life stages. Because the level of investment in defences should match local risk conditions, we predict that these individuals should have the ability to modulate the expression of an integrated defensive phe...
Article
Full-text available
As global temperatures increase, fish populations at low latitudes are thought to be at risk as they are adapted to narrow temperature ranges and live at temperatures close to their thermal tolerance limits. Behavioural movements, based on a preference for a specific temperature (T pref), may provide a strategy to cope with changing conditions. A t...
Article
Full-text available
Coral reefs within 10° of the equator generally experience ≤3°C seasonal variation in water temperature. Ectotherms that have evolved in these conditions are therefore expected to exhibit narrow thermal optima and be very sensitive to the greater thermal variability (>6°C) experienced at higher latitudes (≥10°N/S). The impact of increased thermal v...
Article
Full-text available
Increased ocean temperature due to climate change is raising metabolic demands and energy requirements of marine ectotherms. If productivity of marine systems and fisheries are to persist, individual species must compensate for this demand through increasing energy acquisition or decreasing energy expenditure. Here we reveal that the most important...
Article
Full-text available
Fast-starts are brief accelerations commonly observed in fish within the context of predator-prey interactions. In typical C-start escape responses, fish react to a threatening stimulus by bending their body into a C-shape during the first muscle contraction (i.e. stage 1) which provides a sudden acceleration away from the stimulus. Recently, simil...
Article
Full-text available
In intertidal environments, the recurring hypoxic condition at low tide is one of the main factors affecting fish behaviour, causing broad effects on ecological interactions. We assessed the effects of hypoxia on lateralization (e.g. the tendency to turn left or right), a behaviour related to brain functional asymmetry, which is thought to play a k...
Technical Report
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Elizabeth and Middleton Reefs are of considerable ecological importance. They are the southernmost open ocean platform reefs in the world, and support a unique mix of tropical and subtropical species, including several endemic species. Due to their isolation they also provide a refuge for the ‘vulnerable’ black cod. The purpose of this study was to...
Technical Report
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Spencer Gulf is the most significant economic growth area in South Australia. A lack of deep-water port facilities to meet export capacity has led to a number of companies proposing new port developments. An increase in shipping to the region is expected associated with mining and other infrastructure developments. Upper Spencer Gulf (USG) is world...
Article
Full-text available
Unsteady water flows are common in nature, yet the swimming performance of fishes is typically evaluated at constant, steady speeds in the laboratory. We examined how cyclic changes in water flow velocity affect the swimming performance and energetics of a labriform swimmer, the shiner surfperch, Cymatogaster aggregata. Using intermittent-flow resp...
Article
Full-text available
Current velocity in aquatic environments has major implications for the diversity, abundance and ecology of aquatic organisms, but quantifying these currents has proven difficult. This study utilises a simple and inexpensive instrument (<$150) to provide a detailed current velocity profile of the coral-reef system around Lizard Island (Great Barrie...
Article
Large-bodied fish are critical for sustaining coral reef fisheries, but little is known about the vulnerability of these fish to global warming. This study examined the effects of elevated temperatures on the movement and activity patterns of the common coral trout Plectropomus leopardus (Serranidae), which is an important fishery species in tropic...
Article
Sedimentation is a substantial threat to aquatic ecosystems and a primary cause of habitat degradation on near-shore coral reefs. Although numerous studies have demonstrated major impacts of sedimentation and turbidity on corals, virtually nothing is known of the sensitivity of reef fishes. Planktivorous fishes are an important trophic group that f...
Article
Full-text available
Full text available at http://jeb.biologists.org/lookup/doi/10.1242/jeb.082925 Metabolic rates of aquatic organisms are estimated from measurements of oxygen consumption rates (MO2) through swimming and resting respirometry. These distinct approaches are increasingly used in eco- and conservation physiology studies; however, few studies have teste...
Article
Full-text available
Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a ran...
Data
Meta-data for comparative analysis of the energetic swimming performance of reef fishes, scombrid, and non-scombrid fishes. (DOC)
Article
Full-text available
Increasing sediment onto coral reefs has been identified as a major source of habitat degradation, and yet little is known about how it affects reef fishes. In this study, we tested the hypothesis that sediment-enriched water impairs the ability of larval damselfish to find suitable settlement sites. At three different experimental concentrations o...
Article
Tropical coral reef teleosts are exclusively ectotherms and their capacity for physical and physiological performance is therefore directly influenced by ambient temperature. This study examined the effect of increased water temperature to 3 °C above ambient on the swimming and metabolic performance of 10 species of damselfishes (Pomacentridae) rep...
Article
Full-text available
Schooling can provide fish with a number of behavioural and ecological advantages, including increased food supply and reduced predator risk. Previous work suggests that fish swimming using body and caudal fin locomotion may also experience energetic advantages when trailing behind neighbours. However, little is known about the potential energetic...