Does rock type account for variation in mussel attachment strength? A test with Brachidontes rodriguezii in the southwestern Atlantic

Table 1 Study site coordinates and rock type/s. Measures of relative rock hardness, surface friability, and wave exposure (SE slope) are also included (see footnotes for description and “Study Area” section for methods)

Site	Latitude (S)	Longitude (W)	Rock type	Hardness^a	Friability^b	SE slope^c
Atlántida	37°51′06″	57°30′21″	PL	0.05	6.56	0.73
Frente Mar	37°51′30″	57°30′32″	PL/OO(I)	005/0.67	7.73	0.71
Playa Dorada	37°52′18″	57°30′53″	PL	0.07	4.53	0.72
Camet	37°56′04″	57°31′52″	PL	0.04	8.89	0.63
Punta Iglesia	37°59′48″	57°32′27″	OO	0.67	0.48	1.7
Playa Chica	38°01′16″	57°31′38″	OO	0.57	0.92	2.02
Punta Cantera	38°04′51″	57°32′08″	OO	0.67	0.84	1.06
Faro Punta Mogotes	38°05′36″	57°32′28″	OO	0.8	0.95	1.7
Los Acantilados	38°07′28″	57°35′56″	PL	0.03	1.41	0.81
Chapadmalal	38°11′02″	57°39′14″	PL/OO(I)	0.07/0.67	6.87	0.74
Las Brusquitas	38°14′43″	57°46′33″	PL	0.04	8.17	0.79
Copacabana	38°14′50″	57°46′50″	PL/OO(I)	0.05/0.57	7.14	0.79
Punta Hermengo	38°17′14″	57°50′12″	PL	0.09	3.79	1.11
Rocas Negras	38°21′53″	58°01′16″	PL	0.15	2.27	1.01

PL, Pliocene–pleistocene loess cemented by calcium carbonate; OO, Ordovicic orthoquartzite; OO(I), human-introduced Ordovicic Orthoquartize (groins and revetments)
^aInverse of the mean depth (mm) of 4 replicate holes (4 mm diameter) drilled during 30 s with a power drill [42]
^bWeight per area unit (mg cm⁻²) of particles detached from the rock surface by three squared, ca. 5 cm side pieces of duct tape
^cMean slope (%) from the sampling point to the 5 m isobath in the Southeast direction (the average direction of strong swells) estimated from nautical charts

ISSN: 1438-3888