Dataset: Kelletia kelletii size-frequency population survey data collected by scientific SCUBA divers at 36 kelp forest habitat sites across the species’ biogeographic range in 2015, 2016 and 2017

Sizes of Kellet’s whelk (Kelletia kelletii) individuals, defined here as maximum shell length, in populations in the wild were obtained from subtidal benthic surveys conducted by scientific SCUBA divers at kelp forest habitat sites across the species’ biogeographic range and over multiple years. At each site, up to six belt transect population surveys were conducted; within each, divers systematically counted and measured every visible Kellet’s whelk individual, including cryptic individuals in the survey area but not including individuals hidden from sight under the substrate (i.e., non-invasive sampling, avoiding turning over rocks and digging in sand). To increase sample size at some sites, additional systematic surveys were conducted within 10 m of the transect. 

 

These population surveys were focused specifically on Kelletia kelletii and are hereafter referred to as Kelletia kelletii surveys (KkS). KkS survey data were collected in 2015, 2016 and 2017 from 36 benthic kelp forest sites (5 - 28 m depth), from Monterey Bay, California, USA to Isla Asuncion, Baja California Sur, Mexico. [***CONTENT COPIED OVER BY INFO FROM CORRESPONDANCE WITH C.W.***] Expanded and Historical range sites are differentiated per row within the primary data file. Expanded range sites are along the central California coast north of Pt. Conception (34.4486° N, 120.4716° W), while historical range sites are on the other side of Pt Conception in the Southern California Bight, USA and Baja California, Mexico.

 

The surveys were conducted during summer months (June through August). Individual whelks were transported to a surface vessel and measured, then transported back to their collection location. Whelk size was measured to the nearest mm using calipers and recorded on dive slates or field notebooks, then transcribed to a datasheet and electronic database in the lab.