Ok, the Mohawk was a blast, but now back to our sanctuary science series.
A couple years ago, my dive buddy Phil and I encountered a massive school of gray snappers on the south end of Molasses Reef. There were thousands of them. And I had my macro lens on the camera. Oh well.
Was this a spawning aggregation? Knowing what I know now, I believe it was. Photographing a spawning aggregation is now on my bucket list.
When I created my sanctuary map, one of the layers I used was known and/or observed fish aggregation sites. On my map, they are all in newly designated protected areas. All of them. And I hope we find more and extend the boundaries to cover them, too.
We are getting down to the wire, with only two more working group meetings. I would love to get input from you. Our last homework assignment was to suggest changes to existing zones. Believe me, I did. If you write to me, I will be happy to discuss what my vision is for these areas. I got help from a few people, and made a new map.
How do we know where to find them? Historical and anecdotal evidence aside, there is a field of science that looks at the geophysical characteristics of the reef tract, and can predict potential aggregation sites.
Dr. Will Heyman of LGL Ecological Research Associates, Inc. is a leader in the field. He was gracious enough to take time to teach me about his work. In Belize and the Caymans, there are many known spawning sites for snappers and groupers. He examined all the characteristics of those sites and predicted two more sites where the geography was similar. Presto! Both sites had aggregations.
In his words, "In the Cayman Islands and Belize, fish choose shelf-edge reef promontories for spawning, and share these areas with other species. These multispecies spawning aggregation sites are generally located near the inflection points of convex-shaped reefs, in 20-40 m water depth, adjacent to sharp shelf edges where water depth drops to several hundred meters.
Reef geomorphology may be the key determinant for the selection of reef fish breeding habitat." See his profile here: http://lgl.com/en/staff-directory/147-heyman-will and his work here:http://tamu.academia.edu/WilliamHeyman
Here is the scoop: There are a host of characteristics which, when all are present, provide a high probability of success for predicting spawning aggregation sites.
I asked Dr. Heyman how that relates to the Keys. My thought is, since the Keys are a much longer, less "curvy" arc than the more spatially concentrated sites in Belize or the Caymans, the predictive power of the model may be reduced. That is partially true. He said we have a great deal of contours and bumps along the reef tract that exhibit enough of the characteristic mix to be potentially viable as aggregation sites not previously identified.
A limitation is we do not have detailed maps yet throughout the Keys.
One area he specified as important was Western Dry Rocks. He said that if an assessment were taken now, fish populations may not indicate its spawning importance because of fishing pressures. However, as was the case with the Dry Tortugas, when fishing pressure was reduced, the spawning activity exploded within a few years. Another point is that in sites where protection has occurred, local users have begun to use the sites non-destructively for ecotourism dive destinations.
These are very compelling reasons for new areas of protection. Some people are of the opinion that a temporal closing of these sites will suffice. I disagree.
One of the charts Danielle Morley from Fish and Wildlife Conservation Commission (FWC) showed during her presentation lists key species and the months they spawn. There is not one single month where some species is not spawning. If we have, in the geophysical sense, established spawning areas based on the best available science, these areas should be closed all the time.
Closing areas on a temporal basis, to me, is species management, not ecosystem management. Multispecies sites should be protected at all times.
Why is it important to protect spawning fish? The answer is obvious. But let's look at reality. Recently FWC law enforcement officers spent a month zipping around the Lower Keys and the Dry Tortugas. What did they find? Fishers were heavily targeting the mutton snapper spawning aggregations. They issued citations to both commercial and recreational boats for various equipment and limit violations. To me, that's not good enough. They should be impounding boats and gear, and selling it at auction. See the story here: http://www.keysnet.com/2013/06/01/487265/fwc-crew-nails-15-for-fishing.html
We know we have an extreme shortage of law enforcement on the water. Time to up the ante. We need to start kicking butt and taking boats. If folks are disrespecting the resources, they should not be here. Plain and simple. For those fishers that operate within the guidelines, behavior as documented in the FWC effort must be difficult to tolerate. They are the ones really getting hurt. Activity like this does not enhance their reputation as stewards of their own livelihood.
Note to the rulemakers: Operations like these should generate revenue from auctioned boats and gear, and massive fines. FWC should be pulling in enough money to put gas in boats and people on the water. Give law enforcement officers an impound authority so they can get these offenders out of here. 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 firstname.lastname@example.org or through his web site at www.timgimages.com. Tim is a member of the Ecosystem Protection Working Group for the Florida Keys National Marine Sanctuary Advisory Council.