The ratio is what carries this paper. A mean individual home range of 1,498 square kilometres [7] sits inside a reserve of 198,000 square kilometres [6], which is roughly three quarters of one percent of the protected area [17]. That is a small slice to defend, but the slices are not the same slice: four of the nine tagged animals used waters around two or three islands [8][19], so the union of the ranges is what has to stay in good condition rather than any one bay.
The residency finding also needs its duration read carefully. The study spans three years [2], while the longest individual track ran 418 days, and tracks typically ended when a tag fell off or stopped transmitting [5]. That is about 38 percent of the three-year window for the best-followed animal [18]. The authors say as much, warning that this is a snapshot and that periodic long-distance dispersal may have been missed [11]. "None left the reserve" is therefore a statement about nine overlapping tracks of limited length, not nine turtles watched continuously for three years.
Sex composition matters more here than sample size usually does. Seven of the nine tagged adults were male and two were female [4], so 22 percent of the sample belongs to the sex whose movements the central question depends on [20]. Co-author Juan Pablo Munoz Perez of the Universidad San Francisco de Quito says female yellow morphs are not known to nest on Galapagos beaches, and that the team expects them to eventually return to natal beaches in the western Pacific [12]. The tags did not record that crossing, and two females is a thin base for either confirming or ruling it out.
Set the two morphs side by side and the governance picture inverts the tidy version. The yellow morph appears to do all of its feeding inside a single country's reserve while its reproduction is presumed to happen at the far side of the Pacific [12]. Some black-morph females nest in the Galapagos but may travel to other oceanic islands or to feeding grounds off Central and South America [13]. The archipelago is the only known water where both forms coexist and graze the same marine plants [14], which are the seagrasses and algae that adult green turtles live on [21]. Same pasture, opposite exposures.
The corridor detail is the operational one. Movement between islands showed up only in the cooler months from April to October [9], and the animals stayed in shallow coastal water except for occasional trips up to 25 kilometres offshore [10]. Rowe, of Alma College and corresponding author on the Frontiers in Amphibian and Reptile Science study [3], puts the requirement plainly: because individuals may rely on waters around multiple islands, foraging habitat should be kept intact across all of them and not allowed to degrade anywhere [16]. The morphs are also not physiologically interchangeable, since yellow morphs grow faster than black morphs when young [15].
