The lab-field continuum in conservation physiology research: leveraging multiple approaches to inform policy and practice.

In the field of conservation physiology, there is often a trade off between conducting research in controlled laboratory settings or in inherently variable field environments. However, this belief sets up a false dichotomy where laboratory experiments are perceived as providing precise, mechanistic understanding with low variability at the cost of environmental realism while field studies are ecologically relevant but criticized for generating inconsistent evidence that is difficult to interpret and replicate. Despite the perceived binary view, these approaches are not in opposition to one another, but rather form a continuum along increasing ecological complexity.

Unintended Consequences of Aquatic Enrichment in Experimental Biology.

Enrichment in aquatic animal studies is important for promoting welfare and maintaining animal health and can be categorized by physical, sensory, social, occupational, and dietary enrichment. However, the risk of potential chemical leaching associated with physical enrichment items has been largely overlooked (i.e.

Acute toxicity testing of 6PPD-quinone on the estuarine-dependent sport fish, Sciaenops ocellatus.

Recently, large-scale fish kills in the Pacific Northwest were linked to tire wear particles (TWPs) left on roadways, with the lethality attributed to 6PPD-quinone. which has a median lethal concentration of <1 µg/L for selected salmonids. However, there remains a paucity of 6PPD-quinone toxicity values developed for estuarine fish species, which is particularly significant because estuaries receiving inflows from highly urbanized watersheds are especially vulnerable to TWP contamination.

Implications of biotic factors for toxicity testing in laboratory studies.

There is an emerging call from scientists globally to advance the environmental relevance of laboratory studies, particularly within the field of ecotoxicology. To answer this call, we must carefully examine and elucidate the shortcomings of standardized toxicity testing methods that are used in the derivation of toxicity values and regulatory criteria. As a consequence of rapidly accelerating climate change, the inclusion of abiotic co-stressors are increasingly being incorporated into toxicity studies, with the goal of improving the representativeness of laboratory-derived toxicity values used in ecological risk assessments.

Hypoxia acclimation improves mitochondrial efficiency in the aerobic swimming muscle of red drum (Sciaenops ocellatus).

Environmental hypoxia (low dissolved oxygen) is a significant threat facing fishes. As fishes require oxygen to efficiently produce ATP, hypoxia can significantly limit aerobic capacity. However, some fishes show respiratory flexibility that rescues aerobic performance, including plasticity in mitochondrial performance.

The role of carbonic anhydrase-mediated tissue oxygen extraction in a marine teleost acclimated to hypoxia.

With the growing prevalence of hypoxia (O2 levels ≤2 mg l-1) in aquatic and marine ecosystems, there is increasing interest in the adaptive mechanisms fish may employ to better their performance in stressful environments. Here, we investigated the contribution of a proposed strategy for enhancing tissue O2 extraction - plasma-accessible carbonic anhydrase (CA-IV) - under hypoxia in a species of estuarine fish (red drum, Sciaenops ocellatus) that thrives in fluctuating habitats. We predicted that hypoxia-acclimated fish would increase the prevalence of CA-IV in aerobically demanding tissues to confer more efficient tissue O2 extraction.

Pyrene drives reduced brain size during early life exposure in an estuarine fish, the red drum (Sciaenops ocellatus).

Crude oil and the constituent polycyclic aromatic hydrocarbons (PAHs) induce a consistent suite of sub-lethal effects in early life stage fishes. It has been suggested that 3-ring PAHs drive cardiotoxicity and that all other impacts are downstream consequences of these cardiac effects. However, recent studies have documented behavioral alterations that may not be linked to cardiotoxicity.

The additive effects of oil exposure and hypoxia on aerobic performance in red drum (Sciaenops ocellatus).

Aerobic scope, the difference between standard metabolic requirements and maximum metabolic capacity, is considered a particularly important metric influencing ecological success in fishes. Crude oil exposure can impair cardiorespiratory function in fishes, which reduces maximum metabolic rate, aerobic scope, and may impair ecological performance. Oil exposure is not the only environmental stressor that can affect aerobic scope, especially in areas affected by crude oil spills.

Effects of hypoxia on swimming and sensing in a weakly electric fish.

Low dissolved oxygen (hypoxia) can severely limit fish performance, especially aerobically expensive behaviours including swimming and acquisition of sensory information. Fishes can reduce oxygen requirements by altering these behaviours under hypoxia, but the underlying mechanisms can be difficult to quantify. We used a weakly electric fish as a model system to explore potential effects of hypoxia on swim performance and sensory information acquisition, which enabled us to non-invasively record electric signalling activity used for active acquisition of sensory information during swimming.