A major constraint of the model is the spread of sampling over all possible habitats within the global distribution of white abalone and the variability of abalone densities throughout its range. The model assumes that the population estimate is based on a representative sample. Power analysis using the current sample may provide insight into how much more sampling is necessary to achieve an estimate with a predictable error for management purposes.
6. Project Management
6.1 Timing and Logistics
The planning horizon for each ROV cruise commences 6 months ahead of the cruise with a request for ship time. Ship time is a block of NOAA resources dedicated to each facility. How the time is allocated is related to the research priorities included in the NOAA corporate plan and implemented by each facilities director of research. Ship time is also dependent on the US federal budget.
To test gear, procure spares and pack the ROV, the team needs several weeks of preparation prior to the first cruise of every sampling season. A checklist for logistics is provided in Appendix XII.
Running a ROV program requires a team of personnel with a variety of divergent skills. Of critical importance is staff with technical experience in ROV systems. These include mechanical skills (for replacing thrusters, maintaining vacuum seals and managing the cable systems), electrical/electronic skills (for trouble shooting and repairing tether connections, running power safely and repairing the various electronic boards in the system), piloting skills (for flying the ROV to collect data) and computer skills (to integrate the ROV data producing hardware with real time computer logging of the ROVs position).
With so much expensive technical equipment to worry about the scientific aims of the project can be overshadowed. It is therefore important that other staff take ownership of the survey design, data collection, metadata logging, data back-ups, archiving and analysis. Writing of cruise reports, internal reports to NOAA management, popular articles, and journal publications are another set of tasks where one or several team members should focus their efforts.
The bridge officers are another integral part of the team and require fine helm skills to navigate safely in the hazardous operating environment where cables and a ROV are deployed from the deck. The project also requires skilled deck crew with crane, winch and cable experience. In particular, the bosun works closely with team scientists when loading and unloading at the dock as well as during ROV deployment and retrieval.
The project also needs personnel that can “translate” between all of these various specialists as jargon and incorrect assumptions over roles and responsibilities can foil the projects objectives.
Occupational health and safety is the responsibility of all staff, including both NOAA corps and scientists. A modern method of controlling risk is Job Safety Analysis (JSA). This involves all members of teams involved in particular tasks meeting and breaking the task into its component steps, identifying the risks involved in each step and developing safe work practices to remove these risks. JSA’s are not prescriptive documents, but rather are verbal, collaborative agreements that are performed by the team for each new task and are adapted to each new experience. When a new member joins the team they are briefed in the safe work practices developed by the JSA. This briefing occurs on site immediately before the task is performed.
In JSA the use of protective gear should be a last resort. Rather, removing personnel from the area of risk is the first principle. The key is to develop safe work practices. ROV tasks, which require Job Safety Analysis (JSA), include loading and unloading vessels, Laboratory and ROV setup, ROV deployment, ROV transects and ROV recovery.
ROV operations require clear communications between the lab, the helm, and the deck. This allows for not only successful science, but also the avoidance of catastrophic events, such as entanglement of the propellers by the ROV tether or the snagging of the clump-weight on the bottom. Communication needs to involve both ROV personnel and ship personnel, as the rigors of the scientific technique must be consistent with safe boating and the limitations of tide, sea, swell and wind. The language of sailors and scientists is also often infused with colloquialisms and jargon adding to the potential for confusion.
The key to successful ROV operations is early and repeated briefings between the scientists, the captain, the officers, and the boson. From these briefings standard guidelines (Appendix X) can be developed so all staff are working under the same assumptions.
Smaller vessels can allow for direct verbal communication between scientists and crew during ROV flights. The complexity of communication links increase, however, with the size of the boat. Larger vessels often have various watches, so the helm rotates between a number of officers and communication between the lab, bridge and deck is often conducted via radio. On an ocean going vessel, such as the 53m R/V David Starr Jordan, radio/ships telephone communication links need to be established between the lab and the bridge, the lab and the deck scientists, the deck bosun and the bridge, the deck bosun and the crane operator, and the bridge and the engine room (to stop propeller rotation in an emergency).
An additional communication tool is to run two screens from the computer running the WinFrog program to both bridge and the lab. This allows the bridge to see what the lab sees for the location of transects and of the ROV in relation to the ship. Of added interest to the bridge is that the WinFrog view allows for an excellent visualization of the ship rate and direction of drift.
As the focus of marine science moves from extraction to conservation the use of ROVs will inevitably increase. This is because conservation focused research requires that non-destructive sampling techniques be developed. As marine biologists increase their use of ROVs a prime consideration is how can ROV systems be adapted for quantitative ecology? Precisely determining search effort is the main problem of video analysis and it is in this area that the SWFC research on white abalone is establishing a robust solution.
By integrating DGPS, directional hydrophones, and pitch and roll sensors with frame analysis of the ROV path, for the first time an accurate and precise estimate of ROV search effort can be achieved. This will allow for a precise stock estimate to be produced for white abalone.
Following stock assessment the next phase of the work is to continue sampling to develop an extended time series. The time series will provide performance assessment of the recovery plan by monitoring the response of the abalone population to protection and other conservation measures, such as re-seeding. To avoid seasonal confounding of the data, or pseudo-replication, a single yearly data point should be established for each sampled location by repeating surveys at the same time each year.
As the project moves into this new phase the efficiency of the current transect length should be scrutinized. The key questions are:
Is the current transect length optimal for developing time series data?
What is the power of the current design and is it acceptable to management?
What will be the most efficient designs over the long term involves a number of considerations and may be an ideal question for modeling using computer simulations of the data already collected. Of primary importance is the biology of the white abalone. If the species is patchily distributed rather than uniformly or randomly, then a greater number of shorter transects within more detailed strata may be ideal. The power of time series to detect change is also greatly enhanced if the design moves from being randomized to including repeated measures (Bausell and Li, 2002).
These statistical considerations, however, are limited by the logistical constraints of transiting to sites, launching and retrieving the ROV, crew fatigue, and the weather. While power modeling may indicate one design optimal, cost benefit analysis and unforeseen technical difficulties may limit what can actually be achieved. The combination of modeling and cost benefit analysis is necessary to find the level of sampling necessary to detect a change in the population that can be discussed with management for future funding opportunities.
A further task that is included in the planning horizon is the establishment of a captive breeding and release program. Once again the ROV will be an invaluable tool for this project, providing dive-planning information. Due to the depth and scarcity of the white abalone distribution, divers collecting abalone will have limited dive times. The ROV will be used to conduct the search and then direct divers to the location of specimens. Following the establishment of a captive breeding program the ROV could also be used in experiments to determine the optimum size of white abalone for release back into the wild.
Thanks to Scott Mau and David Murfin for participating in the preparation of the logistics section, Frank M. Caimi for help with the statistics, and Benjamin Maurer and Anthony Cossio for their participation in the cruises and help with the ROV system.
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