Semester of Graduation

Spring 2020

Degree

Master of Science (MS)

Department

Oceanography and Coastal Science

Document Type

Thesis

Abstract

Generally, marine fishes have very high fecundity with each female producing many small eggs which hatch into small larvae. However, Ariopsis felis, a species of marine catfish common to coastal Louisiana, has low fecundity and produces the largest eggs of the teleost fishes. Despite wide range and generally high abundance, we know very little of A. felis biology and population. The few existing studies of A. felis are older and often have questionable or unclear methodology.

I examined four aspects of A. felis reproductive biology: 1) reproductive timing,

2) fecundity, 3) length at first maturity, and 4) mouth brooding. I observed a clear peak of A. felis GSI April-June and rarely observed a GSI above 1% outside of these months. I found A. felis annual fecundity ranged higher than previously reported. A logistic regression showed an L50 of 153mm for female A. felis. While I did observe A. felis mouth brooding, sampling techniques precluded observing mouth brooding in large enough numbers to draw conclusions.

I then performed stable isotope analysis on white muscle tissue to determine if A. felis exhibit an ontogenetic trophic niche shift. I found A. felis trophic niche position varied significantly between mature and immature A. felis. However, A. felis trophic niche width did not vary significantly and mature and immature A. felis exhibit a high degree of trophic niche overlap. The insignificant difference in A. felis trophic niche width coupled with the high degree of trophic niche overlap is evidence that A. felis do not undergo an ontogenetic trophic niche shift in coastal Louisiana. Understanding how abundant coastal fishes reproduce and eat is an important aspect of coastal and estuarine management. This research begins to fill the knowledge gap in A. felis reproduction and trophic dynamics in coastal Louisiana.

Committee Chair

Midway, Stephen

DOI

10.31390/gradschool_theses.5046

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