Effects of Exposure of Pink Shrimp, Farfantepenaeus duorarum, Larvae to Macondo Canyon 252 Crude Oil and the Corexit Dispersant

Susan Laramore,William Krebs,Amber Garr

doi:10.3390/jmse4010024

Abstract

The release of oil into the Gulf of Mexico (GOM) during the Deepwater Horizon event coincided with the white and pink shrimp spawning season. To determine the potential impact on shrimp larvae a series of static acute (24–96 h) toxicity studies with water accommodated fractions (WAFs) of Macondo Canyon (MC) 252 crude oil, the Corexit 9500A dispersant, and chemically enhanced WAFS (CEWAFs) were conducted with nauplii, zoea, mysid, and postlarval Farfantepenaeus duorarum. Median lethal concentrations (LC50) were calculated and behavior responses (swimming, molting, light sensitivity) evaluated. Impacts were life stage dependent with zoea being the most sensitive. Behavioral responses for all stages, except postlarvae, occurred at below LC50 values. Dispersants had the greatest negative impact while WAFs had the least. No short-term effects (survival, growth) were noted for nauplii exposed to sub-lethal CEWAFs 39 days post-exposure. This study points to the importance of evaluating multiple life stages to assess population effects following contaminant exposure and further, that the use of dispersants as a method of oil removal increases oil toxicity.

Highlights

The Gulf of Mexico (GOM) has some of the most productive coastal bodies of water in the world, making it a major source for the U.S seafood industry and the most economically important of all domestic commercial seafood harvesting sectors [1]
On April 20, 2010 the Deepwater Horizon (DWH) oil platform exploded resulting in 200 million gallons of oil being released into the GOM until the well was capped on July 15 [7,8]
The predominant compound was napthalene, which made up 83.5% of the compounds in the water accommodated fractions (WAFs) and 65% of the compounds in the chemically enhanced WAFs (CEWAFs) stock solution

Summary

Introduction

The Gulf of Mexico (GOM) has some of the most productive coastal bodies of water in the world, making it a major source for the U.S seafood industry and the most economically important of all domestic commercial seafood harvesting sectors [1]. The fishery consists of three major species: brown shrimp (Farfantepenaeus aztecus), pink shrimp (Farfantepenaeus duorarum), and white shrimp (Litopenaeus setiferus) [3]. Both the pink and white shrimp began migrating offshore to spawn in the spring, with continued spawning migration throughout the summer (pink shrimp) and fall (white shrimp), while the spawning season for brown shrimp is less defined in terms of season [4,5,6]. While dispersant use decreases the amount of surface oil lessening the amount of oil that reaches shorelines, the small dispersed droplets that remain in the water column are made available to pelagic organisms that inhabit the water column [7]

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