Impact of recreational power boating on two populations of northern map turtles (Graptemys geographica)

Abstract

ABSTRACT1. Recreational power boating is growing in popularity in North America. This activity is known to have lethal and sub-lethal effects on aquatic wildlife and freshwater turtles may be particularly sensitive to this activity.2. This study reports on patterns of traumatic injuries inflicted by powerboat propellers to northern map turtles (Graptemys geographica) from two sites differing in boat traffic intensity in Ontario, Canada.3. The relative vulnerability of turtles was assessed, in light of seasonal patterns in boat traffic, as a function of sex-and age-specific movement patterns, habitat use, and basking behaviour obtained by radio-telemetry. Population viability analyses (PVA) were also conducted to evaluate the potential demographic consequences of mortality induced by powerboats.4. The prevalence of propeller injuries was two to nine times higher in adult females than in adult males and juvenile females. Patterns of movement, habitat use, and aquatic basking indicated that adult females are more exposed to collisions with boats. PVA showed that boat-induced mortality in adult females could lead to rapid population extinction if the risk of mortality when hit by a boat is greater than 10%.5. The results of this study showed that recreational power boating is a serious threat to northern map turtles, even under moderate boat traffic. The need to adopt measures restricting boat traffic in areas important to turtles is discussed.

Investigation of the Effects of Ship Induced Waves on the Littoral Zone with Field Measurements and CFD Modeling

“…The direct contact with the propellers may cause mechanical damage to aquatic animals [1] and plants. Oil and fuel contaminations may affect the water quality [2].…”

Little boats and big concerns? Seeking a balance between ecotourism and motorboat use in Tortuguero, Costa Rica.

“…Disturbances are typically greater with higher visitation (greater boat use), and boat use can also degrade wildlife habitat (Crawford, 1994). High motorboat traffic6 can also cause direct injuries and/or deaths to animals via boat strikes and propeller hits (Bulte, et al, 2010;Grant & Lewis, 2010). Traffic can alter animal behavior (Bellefleur, Lee, & Ronconi, 2009;Nowacek, et al, 2004), and can damage coastal seagrass beds (Engeman et al, 2008).…”

“…seagrass beds), and air-breathing aquatic organisms that surface in order to breathe and/or bask in the sun (e.g. turtles, marine mammals, manatees7), are more susceptible to motorboat impacts because of their behaviors and the spaces that they occupy (Bulte, et al, 2010;Panigada et al, 2006). Despite research involving boat impacts on marine mammals being common (e.g.…”

“…Despite research involving boat impacts on marine mammals being common (e.g. Johnson & AcevedoGutierrez, 2007;Miller, Solangi, & Kuczaj, 2008;Stensland, Carlen, Samblad, Bignert, & Berggren, 2006;Williams, Lusseau, & Hammond, 2006), the literature about motorboat impacts on freshwater organisms is limited (exceptions: Bulte, et al, 2010;Graham & Cooke, 2008;Grant & Lewis, 2010).…”

“…In 2006, the National Marine Manufacturers Association (NMMA) estimated that the number o f registered boats in Canada is increasing by a compound average annual rate of 2.6%, suggesting that boating is popular and growing (Bulte, Carriere, & Blouin-Demers, 2010). Similarly, in 2008, the NMMA estimated there to be over 12 million registered motorboats in the US and in 2004, the number of registered boats in the US was increasing by a compound average annual rate of 8% (Bulte, et al, 2010). Moreover, recreational motorboats are generally continuing to increase in both size and power, representing a boating culture increasingly focused on greater size and motor power.…”