Rocky reef biodiversity survey: Punta Pardelas, Argentina

Study Extent

This dataset presents species occurrences and species richness of underwater photoquadrats over rocky reefs in Punta Pardelas, Nuevo Gulf. Sessile species were recorded as percentage cover and mobile fauna as density. This is the first study of benthic communities in Punta Pardelas at three different depth levels: shallow rocky reefs(1-7 m), mid depth rocky reefs (8-15 m) and deep rocky reefs (16-25 m).

Sampling

Divers were equipped with a Canon 100D camera and two Ikelite DS-161 strobes mounted on a stainless-steel structure with a 0.0625 m2 quadrat (0.25 x 0.25 m). The camera had a 18-55 mm Canon lens and all the images were taken with the 18 mm setting, autofocus, ISO 400, Exposure 1/200 s at f/11 and flashes set on automatic TTL. A dive computer (Oceanic Geo2) was mounted on one side of the quadrat to register the depth and temperature of each photoquadrat. Divers carried a monofilament line that towed a surface buoy with a GPS loading a waypoint every 3 seconds (Bravo et al. 2021).

Quality Control

Species names were assigned when the photograph allowed us to observed the organism's characteristics. When identification was inconclusive, only family or genus names were assigned and, in the case of filamentous algae or sponges, functional groups were assigned. Most of the species were identified by the project codirector Gonzalo Bravo which has extensive knowledge and observations of the local species in the field (see: https://www.inaturalist.org/projects/biodiversidad-submarina-de-lacosta- argentina). In some cases, extractive samples were recollected for taxonomic confirmation or description of species not recorded in the area. The taxonomists that contributed to the identification of photoquadrats were Paula Raffo (Algae), Marianela Gastaldi (Porifera), Cristian Lagger (Tunicates), Martín Brogger (Echinodermata), Gregorio Bigatti (Mollusca) and Daniel Lauretta (Cnidaria: Actiniaria, Coralliorpharia). The taxonomic validity of the names was verified using the World Register of Marine Species (WoRMS; www.marinespecies.org). The geo-referencing of photoquadrats was recorded using a Garmin eTrex 10 GPS (WGS84 Datum) with a 5 m accuracy.

Method steps

1. GPS and underwater camera time were synchronized. This was done by aligning the camera clock with the GPS clock before each dive. The GPS was set on track mode recording one waypoint every 3 seconds.
2. The portable GPS (Garmin Etrex 10) was placed in a dry bag on top of a Rescue Can buoy connected to the diver by a monofilament line using a diving reel. Divers maintained the monofilament line as tight as possible to minimize angles between the buoy and the diver.
3. Photoquadrat sampling.
4. Photos were georeferenced using the function “Auto-tag photos” in Adobe Lightroom Classic version: 9.1.
5. Percentage cover of algae and sessile invertebrates was calculated using a 100 point grid overlaid on each photo, using CoralNet software (Beijbom et al., 2015). On the same image all the mobile fauna was counted to calculate density. All the photoquadrats are stored in a public CoralNet source: https://coralnet.ucsd.edu/source/1933/

This database described here is based on photoquadrat taxonomic identification and is supported by local taxonomists. The goal of this study was to update the benthic community data from Punta Pardelas in Nuevo Gulf, Atlantic Patagonia. The taxonomic coverage Fig. 3 includes twelve phyla: Porifera (17%), Mollusca (17%), Rhodophyta (17%), Chordata (14%), Cnidaria (12%), Ochrophyta (8%), Echinodermata (6%), Chlorophyta (4%), Annelida (2%), Arthropoda (1%), Brachiopoda (<1%) and Phatyhelminthes (<1%). The class Calcarea (Porifera), the genus Halcurias (Cnidaria: Actiniaria) and the species Darwinella rosacea (Porifera) represented first records for Nuevo Gulf and were identified by extractive samples by taxonomists.

1. Ascidiella aspersa
   rank: species
2. Aulacomya atra
   rank: species
3. Anthothoe chilensis
   rank: species
4. Aplidium
   rank: genus
5. Austromegabalanus psittacus
   rank: species
6. Asterocarpa humilis
   rank: species
7. Corella eumyota
   rank: species
8. Aequipecten tehuelchus
   rank: species
9. Magellania venosa
   rank: species
10. Bryozoa
    rank: phylum
11. Corynactis carnea
    rank: species
12. Ciona intestinalis
    rank: species
13. Aplousobranchia
    rank: order
14. Ciona robusta
    rank: species
15. Lithophaginae
    rank: subfamily
16. Diplosoma listerianum
    rank: species
17. Halcurias
    rank: genus
18. Hydrozoa
    rank: class
19. Lissoclinum fragile
    rank: species
20. Metridium senile
    rank: species
21. Myxicola
    rank: genus
22. Paramolgula gregaria
    rank: species
23. Parabunodactis imperfecta
    rank: species
24. Clathria
    rank: genus
25. Cliona
    rank: genus
26. Demospongiae
    rank: class
27. Darwinella rosacea
    rank: species
28. Tripalea clavaria
    rank: species
29. Terebellidae
    rank: family
30. Polychaeta
    rank: class
31. Ralfsiales
    rank: order
32. Corallinophycidae
    rank: superclass
33. Codium
    rank: genus
34. Corallina officinalis
    rank: species
35. Colpomenia sinuosa
    rank: species
36. Dictyota dichotoma
    rank: species
37. Rhodymeniophycidae
    rank: subclass
38. Lomentaria clavellosa
    rank: species
39. Phaeophyceae
    rank: class
40. Ulva
    rank: genus
41. Undaria pinnatifida
    rank: species
42. Calcarea
    rank: class
43. Pseudechinus magellanicus
    rank: species
44. Tegula patagonica
    rank: species
45. Leucippa pentagona
    rank: species
46. Arbacia dufresnii
    rank: species
47. Patagonotothen
    rank: genus
48. Ribeiroclinus eigenmanni
    rank: species
49. Helcogrammoides cunninghami
    rank: species
50. Pachycheles chubutensis
    rank: species
51. Doris fontainii
    rank: species
52. Diaulula punctuolata
    rank: species
53. Allostichaster capensis
    rank: species
54. Polycera marplatensis
    rank: species
55. Fissurellidea patagonica
    rank: species
56. Fissurella radiosa tixierae
    rank: species
57. Phrikoceros mopsus
    rank: species
58. Cosmasterias lurida
    rank: species
59. Sebastes oculatus
    rank: species
60. Trapania
    rank: genus
61. Cycethra verrucosa
    rank: species
62. Pleurobranchaea maculata
    rank: species
63. Ophioplocus januarii
    rank: species
64. Odontaster penicillatus
    rank: species
65. Calliostoma
    rank: genus
66. Heterobranchia
    rank: subclass

Nuevo Gulf in Chubut Province, Argentina. We selected 7 rocky reefs grouped in an area of almost 11 km2 in Punta Pardelas.