COMPARISON OF ENDOHELMINTH PARASITES IN BLACK DRUM (POGONIAS CROMIS) AND RED DRUM (SCIAENOPS OCELLATUS) FROM THE SABINE LAKE ESTUARY

The black drum (Pogonias cromis) and the red drum (Sciaenops ocellatus) are two closely related fish species that occur throughout the Gulf of Mexico. These species utilize estuarine systems as brooding grounds for their young, which offers some protection, and readily available food sources to the juvenile individuals. This study sought to understand how endo-parasitic communities of juvenile and sub-adult individuals of these two drum species compared, and sought to determine what the effects of host size and habitat salinity were on the parasitic communities in each fish species and between fish species. We conducted a helminth survey on black drum (n=59) and red drum (n=61) that were caught from Sabine Lake in the spring and summer of 2018. The overall parasitic intensity and the Shannon-Wiener diversity were calculated for each individual fish, and were compared to host size and habitat salinity, respectively, via linear regression to determine effects of the factors on the parasite community. Parasitic communities were compared between fish using Jaccard’s index, Hutcheson-t test of Shannon-Wiener diversity, Percent Similarity index, and a mixed-effects model. Percent similarity index and the mixed effects model were used to determine if host size and habitat salinity affected the similarity of the parasitic communities to one another. From these fish we have identified 38 parasite species (23 nematodes, 6 trematodes, 5 acanthocephalans, and 4 cestodes). The relationship of host size and intensity of parasitic infections was found to be significant for both the black (R2=0.29, p<0.05) and the red drum (R2=0.16, p<0.05). The Jaccard index value was 0.2895, or 28.95% similarity between the communities, and Hutcheson-t did show significant difference (p<0.05) in diversity between the two communities. The highest percent similarities were between the small sized black and red drum, and between the black and red drum caught in the lowest salinities. This study is significant as a primary helminth survey from Sabine Lake, and as new host and locality documentations for several parasite species.