The American horseshoe crab (HSC), Limulus polyphemus, is an economically and ecologically important species in the coastal ecosystem. Horseshoe crabs inhabit the continental shelf and estuaries from Maine to the central Gulf Coast and the Yucatán Peninsula. Although the presence of horseshoe crabs in southern Mississippi is known locally, there are limited data specific to the area and population, particularly regarding spawning and nesting habitat. Surveys of HSC presence, habitat use, and behavior on Mississippi barrier islands were conducted between March and November 2007 to 2009. These data, combined with habitat surveys of the barrier islands, were used to characterize HSC use of these islands. Horseshoe crabs were present on barrier island beaches from March to November, but active spawning and nesting occurred primarily in April and May. Peak abundance varied by year but not between islands surveyed. Nesting activity was only observed on the north side of both islands and was generally clustered in areas with a mild elevation profile. In comparison to other studied populations both in the Gulf of Mexico (GOM) and along the U.S. Atlantic coast, HSC nesting on Mississippi barrier islands followed generally similar patterns, but did display some important differences. Nesting was highest in low energy, well oxygenated habitat, which included the sub-tidal sand flats that are common along these islands. In addition, HSC are smaller than the range-wide mean reported in the literature, but that may be related to these islands being close to the edge of the reported HSC range in the GOM. The continued existence of HSC in Mississippi appears tied to their preference for barrier island beaches as spawning and nursery habitat. More research is needed, but this study documents that the distribution of HSC nesting habitat includes Mississippi beaches and this should be considered as a part of restoration plans being evaluated for these barrier islands.

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In commercial trawl fisheries in the North Pacific and US West Coast, fishermen and scientists are evaluating if artificial lights facilitate escapement of bycaught Chinook salmon (Oncorhynchus tshawytscha) from the trawl by attracting them to an opening provided by a bycatch reduction device. Inconsistent behaviour and escapement rates when lights were used in the trawl led us to conduct a laboratory study to evaluate the role of light properties (intensity, colour, and strobe) on marine Chinook salmon behaviour. Results from this study suggest a negative phototactic response. Light colour and strobe, and the interaction between them, differentially affected behavioural response with regard to mean swimming speed and distance from and habituation to the light. White light intensity had limited influence on response; however, the range of trialed intensities was limited. While behaviour is contextual and responses in a laboratory setting cannot be directly extrapolated to responses in fishing gear, this study highlights the significant role of light properties when trying to affect behaviour for bycatch mitigation and the importance of distinguishing between a response to light and to illuminated surroundings.