Abalone support commercial and recreational fishery, however their population have decline dramatically since 1950's. To understand the recruitment of abalone populations, standarized abalone recruitment modules made of half cinder blocks inside cages were deployed in Baja California and Baja California Sur, Mexico. 12 cages were deployed at three sites (i.e., El Rosario, Isla Natividad and La Bocana) in Mexico. The abundances of abalone and invertebrates found in the cages were checked after 12...
Show moreLOCATION:
Baja California, Mexico. El Rosario
Baja California Sur, Mexico. Isla Natividad and La Bocana
DEPLOYMENT OF CAGES
Twelve cages per site were deployed between 5-40ft, at the three locations (El Rosario, Isla Natividad and La Bocana) and left for 12 months before surveys.
SURVEY OF CAGES
1. Diver 1 opens cage and holds the blocks 1 at a time while Diver 2 fills in the data sheet
2. Diver 2 fills in the datasheet and sets the blocks in a pile off to the side
Part 1 – count and measure focal species
▪ Stop measuring after 30 measurements
▪ Stop counting after 100 counts
▪ Organisms outside or on the cage should not sampled.
Part 2 – identify and qualitatively measure the dominant cover on each block
▪ For each block identify what the most common cover is (CCA, red algae, other)
▪ Determine whether it covers 25, 50, 75 or 100% of the block
▪ But a tally point in the corresponding cell
▪ Each block should only have 1 tally
Part 3 – note presence/absence of Macrocystis/Eisenia algae or sessile invertebrates for each block
3. Once the cage is empty divers inspect the cage and lines, making any minor repairs that are
possible
4. Diver 1 puts the blocks back into the cage 1 at a time while diver 2 keeps track (comments section) of the number of blocks and broken pieces.
5. Close the cage with line and cable ties, ascend for surface interval
INSTRUMENTS:
SCUBA diving equipment
Calipers (150mm)
Ruler
Mesh bag
Transect tape
Slate
Datasheet
Pencils
Snipes/knife
Cable ties
Extra line
GoPro camera
Micheli, F., Hernández-Velasco, A., Rogers-Bennett, L., Smith, A. (2023) Abalone recruitment data from Baja California and Baja California Sur, Mexico in 2019. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2023-10-18 [if applicable, indicate subset used]. doi:10.26008/1912/bco-dmo.907383.1 [access date]
Terms of Use
This dataset is licensed under Creative Commons Attribution 4.0.
If you wish to use this dataset, it is highly recommended that you contact the original principal investigators (PI). Should the relevant PI be unavailable, please contact BCO-DMO (info@bco-dmo.org) for additional guidance. For general guidance please see the BCO-DMO Terms of Use document.