Dive Time with Tim Grollimund

Size matters when it comes to fish protection

July 5, 2013 

A green moray drags a hook and lead weight around the Benwood. (photo by Tim Grollimund)

One day a while back on Deep Molasses, we had traversed quite a long way in a southerly direction along the deep part of the drop, about 80 to 90 feet. We made the turn and were on the way back when we heard a boat overhead.

The water was clear enough to see the boat pull up to the mooring ball and settle in. Next thing I know, I have a baited hook landing on the reef in front of me. Houston, we have a problem!

Depending on the wind direction, a boater may interpret a couple of these mooring balls to be either inside or outside the Sanctuary Preservation Area (SPA) boundary. I guess the interpretation on that day was outside the SPA (or they simply did not know or care). Was this fisher inside or outside the SPA?

While it is a given that the edges of the SPAs are heavily fished, I believe what is confusing is the use of the mooring buoys for fishing on the edge. In my opinion, the markers should be in or out, and not open to a windy interpretation. This is the same section of reef I have found various pieces of fishing gear and damaged sponges.

The most oft-quoted phrase about the definition of SPAs is they were originally intended to mitigate conflicting uses of a specified area. It does not seem to be working here, as I watched a baited hook fall within the range of visibility at 50 feet of depth.

And how does that relate to “size matters?” For the science I am studying as part of the Working Group, size has popped up in a few places, in a few ways.

When Dr. Jerry Ault from the University of Miami spoke to us recently, he emphasized size as mattering in two important ways. When I spoke to him last week, he had just completed a few days of tagging tarpon in Islamorada. Take a look at his work here:http://femar.rsmas.miami.edu/ault.html

One thread that runs through a lot of the overarching studies on marine protected area design is size and distance between no-take areas. Size [and spacing] matters.

According to Dr. Ault, our SPAs are “Postage Stamp” size, and, while they may form a visible demarcation between competing uses, from a sustainability perspective they are not large enough to be effective steward areas for fish and lobsters. As we form recommendations, this is vitally important.

Last week I read a summary of all the condition reports from all of the marine sanctuaries in the nation. Relatively speaking, we do not fare well. While I stipulate our water quality issues are different than most other areas, I also acknowledge we are doing something about it. Our new sewer system is a positive step, and has healthy implications for the future of water quality.

You can see all the condition reports here: http://sanctuaries.noaa.gov/science/condition/. Check the colors on the chart on pages 10-11 of the summary report. The Florida Keys sanctuary is the most stressed of all the sanctuaries. A lot of the exploitation took place prior to the sanctuary designation, meaning resource managers have had an uphill path since inception. All the more reason to tilt the playing field back towards level by implementing ecosystem protection to the max.

When I look deeper into the report at the living resources section, what I find is disturbing. Out of the main group of exploited species, Dr. Ault found 13 of 16 groupers, 7 of 13 snappers, 2 of 5 grunts and hogfish are all overfished. Recent reports have indicated some improvement, but the pressure is still intense. This relates to the second way size matters.

In Dr. Ault’s studies, he examines size — not size of the SPA — but size of the animals. In protected areas animals have the chance to grow and reproduce without being subjected to fishing pressures. One of his main points is that increasing the minimum size of allowable catch is critical for boosting the fishery back to sustainable levels. The benchmark for sustainability is a 30 percent Spawning Potential Ratio (SPR). The SPR compares the spawning ability of a fished species stock to the spawning capability of the stock in an unfished state. An effective way to boost the SPR is to raise the minimum size limit, so more fish can spawn more often.

Some folks make the point that raising size limits will be like closing the fishery until the fish grow. I would point out that since the 1920s, when pressures escalated as the human population of the Keys grew, larger, breeding-viable fish have declined to the point that we are now in an unsustainable position. We need to let the fish get bigger. Providing protection by increasing the size of no-take zones in the sanctuary is a proven way to do that. The postage stamp SPAs are not getting the job done.

If the original definition of a SPA was for the purpose of mitigating user conflicts, perhaps we should augment the definition to include a goal of increasing fish stocks to provide greater spillover effects to unprotected portions. Recommending size and spacing of protected areas and reserves, I believe, is the most important aspect of what we do as a Working Group. My map has larger SPAs and reserves, and is based on what I have learned from the scientists. Write to me and I will be happy to send them to you for your comments and suggestions. As always, these are my thoughts, and are not the official views of the agencies with oversight of the sanctuary.

Tim Grollimund is a freelance photographer and PADI divemaster based in Key Largo. He can be reached at tim@timgimages.com or through his web site atwww.timgimages.com. Tim is a member of the Ecosystem Protection Working Group for the Florida Keys National Marine Sanctuary Advisory Council.

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