Abstract

Flyingfish occupy a crucial link in pelagic food webs, and understanding their distribution and abundance can lead to an improved understanding of their population dynamics. The aim of the present study is to characterize the distribution and abundance of larval flyingfish (family Exocoetidae) and more specifically the species Prognichthys occidentalis in the northern Gulf of Mexico. Here, we report on summer ichthyoplankton cruises conducted in the northern Gulf of Mexico (NGoM) during 2009 - 2011. Samples were collected using neuston nets towed through the upper meter of the water column in the outer shelf and slope waters of the NGoM. Over the three year sampling period, a total of 12,646 flyingfish larvae were collected and 77% of the total catch was comprised of P. occidentalis. Interannual variation was detected with densities of flyingfish larvae higher in 2009 and 2010 (14.9 and 10.0 larvae 1000/m2, respectively) than 2011 (2.7 larvae 1000/m2). Flyingfish larvae were present in each month and year along our sampling transect, and percent frequency of occurrence ranged from 56% in July 2011 to 100% in June 2010, suggesting that flyingfish represent a common and important component of the ichthyoplankton assemblage in the NGoM. Generalized additive models were used to evaluate the influence of oceanographic conditions on the density of all flyingfish larvae and P. occidentalis. The overall flyingfish density model indicates that abundance of larvae increased in waters with lower temperatures and negative sea surface height, which corresponds to frontal boundaries and cyclonic features in the NGoM.

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