Nile tilapia Oreochromis niloticus are routinely transported 1,200–1,400 km from Idaho to live markets in the greater Vancouver, British Columbia, area. Direct hauling mortality is typically very low, but significant economic losses occur during retail holding owing to a deterioration in physical appearance that results in fish that cannot be sold and their subsequent mortality. To address this problem, information was collected on hauling systems and protocols, holding systems and water management protocols, and water quality in the retail holding systems. During hauling, fish are exposed to high levels of dissolved oxygen, carbon dioxide, and bacteria. The transfer of fish from hauling systems to retail holding systems can subject them to rapid changes in temperature, dissolved oxygen, carbon dioxide, and pH. Problem areas in retail holding include low water temperatures, high un‐ionized ammonia concentrations, and elevated levels of gas supersaturation. Determination of the causes of high mortality in transportation and retail holding is difficult to clearly identify because of sampling difficulties and commercial restrictions; improvements in hauling protocols may depend on simulated hauling experiments followed by commercial verification.

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Many anthropogenic disturbances have contributed to the decline of Pacific lampreys (Entosphenus tridentatus), but potential negative effects of contaminants on lampreys are unclear. Lamprey ammocoetes are the only detritivorous fish in the lower Willamette River, Oregon, USA, and have been observed in Portland Harbor sediments. Their long benthic larval stage places them at risk from the effects of contaminated sediment. The authors developed experimental methods to assess the effects of contaminated sediment on the growth and behavior of field-collected ammocoetes reared in a laboratory. Specifically, they developed methods to assess individual growth and burrowing behavior. Burrowing performance demonstrated high variability among contaminated sediments; however, ammocoetes presented with noncontaminated reference sediment initiated burrowing more rapidly and completed it faster. Ammocoete reemergence from contaminated sediments suggests avoidance of some chemical compounds. The authors conducted long-term exposure experiments on individually held ammocoetes using sediment collected from their native Siletz River, which included the following: contaminated sediments collected from 9 sites within Portland Harbor, 2 uncontaminated reference sediments collected upstream, 1 uncontaminated sediment with characteristics similar to Portland Harbor sediments, and clean sand. They determined that a 24-h depuration period was sufficient to evaluate weight changes and observed no mortality or growth effects in fish exposed to any of the contaminated sediments. However, the effect on burrowing behavior appeared to be a sensitive endpoint, with potentially significant implications for predator avoidance. Environ Toxicol Chem 2016;35:2092-2102. © 2016 SETAC.