Prevalence and Transience of Ingested Fishing Hooks in Kemp's Ridley Sea Turtles

Abstract

Abstract In the northern Gulf of Mexico, Kemp's ridley sea turtles (Lepidochelys kempii) are incidentally captured by recreational anglers. While sea turtle bycatch is of conservation concern, most studies focus on commercial fisheries, and the number and proportion of turtles affected by recreational fisheries interactions is not known. This study aimed to quantify the proportion of turtles in the Mississippi Sound with evidence of previous interactions with anglers. We analyzed radiographs of hook-and-line captured sea turtles in rehabilitation for number of hooks present, location of hooks, and number of associated hook interactions. The presence of ingested hooks in a number of the rehabilitated L. kempii also allowed us to report on hook transience through observations in rehabilitation, including how transit time related to turtle size, hook size, and position within the gastrointestinal tract. From 2012 to 2015, 882 L. kempii were radiographed. Hooks from prior interactions were found in 12.5% of our total sample. Carapace length was not significantly related to the probability of gear presence, though carapace length did account for 21.9% of the variation of hook sizes in our sample. Transit times were recorded for 50 successfully expelled hooks. Average transit times were 13.50, 8.40, and 4.48 d for the upper, middle, and lower gastrointestinal tract, respectively. Multiple linear regression models showed that transit time was not related to hook or turtle size. This information can be used to inform sea turtle rehabilitation, conservation, and management decisions while highlighting the need for a better understanding of interactions between sea turtles and recreational fisheries.