Grouper and Lionfish Update ~
Grouper and Lionfish Update ~ Guy Harvey Little Cayman Expeditions 2013
Written by: Guy Harvey PhD Date: April 10th, 2013
From guyharveymagazine.com
My first trip to Little Cayman this year was at the end of January to check in with the Dept of Environment/REEF.org research effort on the Nassau Grouper annual spawning aggregation.
Apart from maintaining a balanced reef ecosystem, the recovery of the species is the primary concern of not only the dive industry in the Cayman Islands but also for local fishermen. Once reduced to a fraction of its pre-exploitation level in all of the Cayman Islands, this iconic species is making a slow, but sure recovery. The research teams are measuring the effectiveness of the fishing bans and limited protections currently in place. As with 2012, there seems to be a small increase in the adult population, but no new juveniles were seen this year after a big recruitment of new fish witnessed in 2012.
The long term plan of all interested user groups is to have this population recover to around ten thousand breeding individuals which represents the “capital investment” in the species and therefore the overall health of our coral reef ecosystem. The population of breeders currently stands at around four thousand adults, all of whom live around Little Cayman. Counts this year at the neighbouring island of Cayman Brac put breeding adults at approximately one thousand individuals. This is the same figure estimated on the last count done five years ago. Why no increase? Because the fishermen around the Brac still fish the SPAG sites and the much higher level of fishing pressure generally in the Brac compared to fishing pressure in Little Cayman.
The legislation that was drawn up in Feb 2012 to protect Nassau groupers throughout their range during the spawning season November 1 – March 31, did not get close to being passed before the breeding season this year, let alone before the CI Legislative Assembly was dissolved before the upcoming General Elections on May 22. Bad news for all. Perhaps a new government will be more understanding of the need for stronger conservation measures for this and other reef predators.
The only protection the groupers currently have is the extended fishing ban on the SPAG sites enacted by the Marine Conservation Board in December 2011. What a good thing that happened, otherwise the Little Cayman site would have no protection this season.
You can imagine what would have transpired as twelve years of hard work would have gone up in smoke. This is not an anti-fishing project, this is an effort to build the stock back to its historical high levels and then regulate the access and fishing pressure on a sustainable basis… which will take some time.
People forget that they hammered the Nassau groupers mercilessly during their spawning season at the aggregation sites, locally called “grouper holes,” for decades and then wondered where they have all gone! That is why they are listed as “Critically Endangered” by the International Union for the Conservation of Nature (IUCN).
Why is this population of Nassau groupers important to the wider Caribbean? The Little Cayman population of NGs is the largest in the known geographic range of the species. The research efforts of the Dept of Environment and REEF are now being used as a template for other Caribbean countries as a model for what can be undertaken in restoring grouper populations. It begins with the research effort, finding out what is remaining and how best to manage, conserve and utilize that resource in a sustainable manner.
Additionally, if this population continues to expand, there is a very strong possibility that it will repopulate Cayman Brac and Grand Cayman with more individuals. That would be a good thing.
On my April expedition my primary goal was to introduce my daughter Jessica to this unique island and show her the amazing nature both above and below the surface. On arrival we stayed at the world famous Southern Cross Club, owned by Peter Hillenbrand. Then we attended the benefit auction for the local branch of the National Trust later that evening.
The National Trust administers the RAMSAR mangrove wetland refuge for red footed boobies, frigate birds and a variety of heron species. The funds are also used to purchase land to conserve endemic rock iguana habitat.
Most people go to Little Cayman for the tranquility and the snorkeling and diving. With just 150 people living on the island, it is like going back in time. Nature is foremost in your vision and thoughts. Next day Jessica and I headed out with three dive guides Mike Shouten, Chris Gough and Henry Herrera plus other guests staying at SCC. Jessica had yet to dive the magnificent Bloody Bay wall. The weather had calmed down and Mike gave us the tour of Mixing Bowl reef. We started out meeting up with a massive barracuda and then several large Nassau groupers that were our constant companions. A couple of these big groupers carried streamer tags from the REEF counting exercise in January. There were several large schools of a variety of reef fish in the shallows around vibrant coral heads and we spotted a queen triggerfish guarding her nest. Going over the wall we passed hawksbill turtles, a green turtle, lobsters, groupers all over the place. So good to see these big fish in abundance. The wall falls vertically from 20 feet to several hundred feet, is covered in sponges and soft corals and even over hangs in places. Just amazing!
But few lionfish were seen. A good thing! This brings me to the next project. All the dive operators who use the 3 mile stretch of the Bloody Wall have been clearing the lionfish out in regular culls. This is a voluntary effort to reduce the impact of the lionfish on the marine park and this unique location; bread and butter to the dive industry here.
Neil van Niekerk, manager at SCC had organized a cull for the afternoon dive. At 4:45 p.m. dive masters from the other dive facilities all arrived at SCC and jumped on the dive boat and headed to a spot on the south side. Carrying DoE-issue short Hawaiian slings and homemade lionfish buckets, the group did a 500 meter swim along the top of the wall. In the evening the lionfish will hunt out on top in the open and are easily seen, while during the day they are cryptic and seek shelter in coral caverns and overhangs. Peter Hillenbrand joined us and we racked up nearly 50 lionfish, Mike Schouten was top scorer with ten. All these fish ended up at the Central Caribbean Marine Institute and were samples for a study being funded in part by the GHOF. This study is investigating lionfish recruitment rates in culled areas as well as diet, growth rates and reproductive rates. As a control there are some areas that are not culled. There will be updates on this research effort in future blogs.
Jessica and I visited the CCMI the following day. Here Rob Hedges the Director of Operations gave Jessica a quick tour of the facility while I visited with Katy Lohr a student from the University of Florida taking all the data off the lionfish we culled. There are other studies on the effectiveness of lion fish culling taking place in the Bahamas and Florida being conducted by REEF. There is no doubt that lion fish tournaments will reduce the population very quickly over a wide area, but the rate of reproduction of the species is so prolific that recruitment of new fish to take over the space is rapid and takes place in just a few months. At best culling will keep the lion fish population contained in limited, often visited areas but outside of these areas the lionfish population will continue to expand.
Jessica also spent time with Mike Vallee the local coordinator for rock iguana research. These endemic iguanas are terrestrial, long lived and grow to a large size on Little Cayman and Cayman Brac. They are often spotted on the grass verges of roads and will use the heat off the tarmac to warm up and so sometimes get hit by cars
Our short time spent at SCC was action packed and just tremendous. The amazing staff there are lead by Jennifer Mills and take care of every detail. While diving is the focus, you can also go bird watching, biking, snorkeling, para-sailing, do guided fly fishing for bonefish, permit and tarpon or go offshore for yellowfin tuna, wahoo and marlin. Or you can just chill out on the amazing beach enjoying an adult beverage while watching the magnificent frigate birds and red footed boobies come and go overhead from their roost to the blue ocean.
How to get there? Just jump on one of the eight daily flights to Little Cayman from Grand Cayman, a thirty minute flight on a Twin Otter and once you get there you won’t need to wear your shoes for the rest of your stay. Their motto is “Barefoot Elegance.”
Fish responsibly, dive safely.
Guy Harvey PhD.
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