May 3st, 2010: LIONFISH UPDATE
Since the first lionfish was reported on Bonaire in October 2009 things have been moving pretty fast in this particular field. An Action Plan was activated to provide information to local population, dive operators, fisherman and tourists. This information is critical to make all interested parties aware of the different aspects of the lionfish presence in our waters. The Action Plan also contains a “removal” plan in order to effectively localize, mark, report and remove as many specimens as we can. To achieve this objective an agreement was reached with CURO (Council of Underwater Resort Operators) to provide tourist divers with critical information about lionfish presence in our reefs. Dive Operators have been collaborating also distributing among their divers “the lionfish marker” (see picture). The lionfish marker is a simple piece of plastic surveyor tape of 1 ¼ inch wide by 3’ to 4’ long. The removal plan is simple: tourist divers are informed in the dive orientation or through different web pages (check www.stinapa.org or www.dive-friends-bonaire.com ) about the problem and the role they can play. Most of the local and visiting divers are already carrying the “lionfish marker”. Once you spot a lionfish the marker is deployed attaching it to a dead piece of rubble near the fish. Divers report directly to the Bonaire National Marine Park or through their dive operator. Once the report enters the “system”, the removal team is activated. Capturing a lionfish is not an easy task, but it is not impossible if you have the right training, material and a lot of patience. The BNMP have been running a series of “lionfish workshops” in order to provide dive operators staff and volunteers with the right knowledge and techniques to capture lionfish. At this moment more than 120 dive operator staff and volunteers are already “certified” as lionfish removal team members. At the moment of this writing 145 lionfish have been removed from our reefs. All captured fish are brought to the CIEE Bonaire Research Station for cataloging and future studies.
Because of the territorial characteristic of this species the chances to relocate the fish around the markers are very high. However, it seems that lionfish have reached sexual maturity and this means more mobility to mate. Some divers have reported in the last 3 to 4 weeks pairs of lionfish swimming together. This change in behavior together with the fact that lionfish reach sexual maturity at around 11 to 13 cm might indicate that these invaders start already to reproduce in our waters. Lionfish can lay thousand of eggs at a time, and they spawn often. It is not clear if these newborns will settle here or seed some downstream areas like Curacao or Aruba. In any case more baby fish are coming……….and they will need food.
The first lionfish captured in Nukove is October 26th, 2009 measured a 5 cm total length (from the snout to the end of the tail) and a few grams in weight. In these days (little bit more than 4 month after the first sighting) we are capturing specimens of 20 cm total length and almost 100 grams in weight. This represents a growing curve not seen in almost any predator fish in the Caribbean (see fig.1). To maintain this growing rate lionfish need to eat a great deal of protein, and there is where the whole problems start. The source of protein comes from our commercially and ecologically valuable reef fish and shrimps. Lionfish are voracious predators and they would eat anything that fits in their mouth. It is well documented that they are more active hunters from late afternoon to early morning, but they won’t refuse an easy prey at any time of the day. This produces a devastating effect in baby fish recruitment impeding fish population to recover from additional problems like overfishing, water quality degradation, habitat lost, etc. There are not many scientific studies about predators controlling lionfish populations. It is believed that in their natural range of distribution (Indo-Pacific and Red Sea areas) after reaching a size of 6 to 8 cm, lionfish do not have many predators. The most probably control factor in the population growth is in their eggs and larvae. Lionfish eggs and larvae settle on the bottom after a period of approximately 25 to 40 days, at a size of 10-12 mm in length. Some planctivores fish (fish that feed on little organisms that float in the sea) might have learned that these eggs and larvae are a good and easy source of food. Of course this learning process takes millions of years to evolve. So, the possibilities of finding help from a natural predator to control the lionfish population in the Caribbean are very slim.
An additional problem that this invasion brings in is that lionfish are highly venomous. Lionfish are one of the most venomous fish in the ocean. Thet have venomous dorsal, anal and pelvic spines that are used purely for defense. When threatened, the fish often faces its attacker in an upside down posture which brings its spines to bear. However, a lionfish's sting is usually not fatal to humans. If a human is envenomed, that person will experience extreme pain, and possibly headaches, vomiting, and breathing difficulties. A common and effective treatment is soaking the afflicted area in hot water (40° to 45° C), as very few hospitals carry specific treatments. However, immediate emergency medical treatment is still advised, as some people are more susceptible to the venom than others.The good news is that lionfish meat is delicious. From a full grown lionfish of about 38 to 40 cm you can obtain two high quality filets. Since the venom is located only in the spines, lionfish meat can be eaten safely. Lionfish venom is still active long after the fish is death so, special care need to be taken to remove the spines before cooking a lionfish. Among the most common ways of venom removal is carefully cutting off the spines. Burning the spines with a torch is becoming also common in some areas of the Caribbean. Hundred of recipes of how to cook a lionfish can be found in the internet. Here some to start www.lionfishhunter.com/Lionfish Recipes.html
Because of the biological characteristics of the lionfish and the ecological characteristic of Caribbean reef environments, it is clear that lionfish has come to stay. Until we can get a “scientific breakthrough” in how to eradicate this invader the best option is to control the number of lionfish in the reef. This option represents an enormous effort but there is no other way to protect our fish population. Confronted with the lack of predators for lionfish, the only viable option is for us to become predators. If you want to join the eradication efforts please do not hesitate in contacting the Bonaire National Marine Park.Written by Ramon de Léon.
