Study on the juvenile recruitments of the spiny lobster (Panulirus argus)


How is it funded, who administers it?


Why was the survey originally designed?


What are/were the intended outcomes/objectives?


Describe the temporal and spatial coverage of the survey

Show the geographic coverage (including depth) of the survey (maps are helpful)

How often is the survey conducted (annually, biennially, biannually etc)?


Is it seasonal?


Describe the underlying experimental design

Fixed site or stratified-random (If stratified-random, describe the strata)?


Describe allocation of sites per strata (proportional/weighted? ) and number of sites


Describe the methodology and gear  




Describe the outputs of the survey

Describe the data outputs & include a discussion of the variance structure of the data


Self-Evaluation of pros and cons of Survey

What suite of species does this survey target (what are gaps)?


What are the gear/method biases (catchability, size selectivity)?


What are the temporal/spatial limitations?


Is this survey expected to continue into the future?


It is relatively expensive/inexpensive, logistically difficult/easy?


Self-Evaluation of utility of survey for generating information for stock assessment

Spatial/Temporal coverage


Data generated: length frequency, spawning stock biomass, mortality etc.


Provide any other information that may be relevant to this discussion


Provide most relevant documentation (w/PDFs or hyperlinks if possible)

SEAMAP-C Sampling Protocol Manual

SEDAR 8, Final report to SEAMAP 2012



Methodology March 2003

On each station a lobster artificial shelter was constructed.  The shelter was built using 16 cement blocks.  Eight of the blocks were placed on the seafloor forming a square shape two cement blocks per side.  The other eight blocks were placed in top of the first layer of blocks.  The blocks were tied to each other with nylon rope.  Identification numbers were assigned to each shelter.  Numbers 1 to 10 were assigned to the shelters in the first set.  Numbers 11 to 20 were assigned to the shelters in the second set.  Acrylic identification tags were attached to each shelter with their ID number engraved on it.  In every other station the shelter was covered with a black canvas Stations with covered artificial shelters were: 2, 4, 6, 8, 10, 11, 13, 15, 17 and 19.  The canvas was hold in place by tying it with steel wire to four steel rods that were nailed to the sea floor, one on each corner of the square.  A cable was tied from shelter to shelter to ease the location of the stations under water.


Starting on March 2003 the stations were visited once a month to collect data on juvenile lobster recruits present on the shelters.  Covered shelters were opened to observe presence of recruits on the inside of the shelter.  Recruits quantity and size information was collected.  The sizes here reported are from the cephalothorax, measuring from the spines to the end of the thorax. Size classification was: less or equal to 1”, from 1.1” to 2”, from 2.1” to 3”, from 3.1” to 4”, from 4.1” to 5”, and greater than 5.1”.  On our last visit, 23 February 2004, the canvases were removed to avoid damage to the adjacent areas by the eventual displacement of these.


Spiny Lobster artificial shelter

Figure 1 Spiny Lobster artificial shelter



Study 2- Artificial shelters for juvenile lobsters 2008

1. Six sets of ten juvenile lobster artificial shelters were constructed at various sites on the west coast platform. Each shelter was at least 30 m apart from each other.

2. Each artificial shelter was built using 16 cement blocks.  Eight of the blocks were placed on the seafloor forming a square shape, two cement blocks per side.  The other eight blocks were placed in top of the first layer of blocks.  The blocks were tied to each other with nylon rope (Figure 1). 

3. Sampling was done monthly between the full and the new moon. 

4. For sampling, divers inspected each shelter once a month and count the number of juvenile lobsters in the shelter. Lobsters were measured using a measuring stick. 

5. Lobsters found on the shelters were left in place.

6. Surveys were clean during each visit and octopuses were removed as possible.


Location of the artificial shelter sets 2003

Figure 1. Location of the artificial shelter sets 2003 


Study 2 - Artificial shelters for juvenile lobsters

Six areas were selected base on depth, bottom type and proximity to a reef (Figure 2).  Table 2 summarizes the coordinates for every artificial shelter within each station.


Table 2 Coordinates of the spiny lobster artificial shelters


Latitude Longitude
Bramadero 18°08.331 67°11.136
El Negro 18°08.795 67°14.208
Fanduco 18°05.002 67°12.435
El Ron 18°06.344  67° 16.046
Combate 17°59.266 67°13.113
Pta. Aguila 17°56.724 67°12.260


Spiny lobster artificial shelter stations 2007-08

Figure 2 Spiny Lobster artificial shelter stations 2007-08