The fish Richie is holding here is a juvenile snapper caught in Placencia Lagoon, Belize. It may not look especially impressive, but when it matures this species can be found in huge spawning aggregations on the Mesoamerica Reef. In April and May, this and other snapper and grouper species congregate in huge schools to spawn.
These spawning aggregations are historically important to the fishers of Belize (and even as juveniles in the lagoon are important to local villages like Seine Bight). The shark in the picture above is a bull shark, but whale sharks also come to consume the free-floating gametes released by snapper. The spawning aggregations and the whale sharks whale sharks who feed on them are known world wide and provide substantial diving tourism income to the nation of Belize.
A study I am doing through the Southern Environmental Association in cooperation with Boston University and funded by the Busch Gardens Sea World Conservation Fund is looking at the role of Placencia Lagoon as juvenile habitat for commercial fisheries species in Belize. Toward that end we have been collecting juvenile snapper from fishers in the lagoon.
During recent history, however, the numbers of fish on these aggregations have declined dramatically. Despite some improvements in numbers of spawning fish inside marine protected areas like Gladden Spit and Silk Cayes Reserve, the number of fish currently present on the reef is dramatically lower than has historically occurred there. Fisheries managers need tools to help protect the spawning populations, restore the spawning aggregations, and preserve the fisheries that have been so important to the nation and ecosystems of Belize.
The question is, how may of these massive and economically important cubera snappers on the reef have spent their life in estuaries like Placencia Lagoon? If that number is substantial, the need to protect and restore these lagoons becomes an agenda of primary importance. Right now, a variety of development pressures around Placencia Lagoon are fundamentally changing the food web there. Sea grass is lost or languishing. Water quality is in decline. The fish in the lagoon appear to be declining.
By analyzing the micro-elements in the earbones of fish, the location of juvenile habitats can be inferred. Elements like strontium are normally higher in the matix of bone that is deposited while fish are growing near shore. Fish earbones or otoliths grow similar to the way trees grow, by adding rings around a central nucleus. By looking at the composition of rings deposited during different ages, we can determine the habitat being used at a specific time. This study is focusing on the upper part of Placencia Lagoon, where specific changes in habitat have been documented. Work by Eli Romero and Les Kaufmann is looking at sites near the mouth of the lagoon and further offshore.
Knowing the source habitat of cubera snapper and other commerically important species found on the reef will help guide management decisions on the Mesoamerican Reef, preserving the natural resources and wonder it provides.
Similarly, stable carbon isotopes are being used to evaluate changes in the diet of the Placencia fishery. Now that much of the seagrass in the lagoon has been lost, we hope to determine if the remaining fish have shifted their diet to other parts of the food web, or if their species have simply disappeared.
Bit by bit the pieces of the puzzle connecting Placencia Lagoon to the wider reef ecosystem are coming together. Many thanks to SEA, Busch Gardens and Boston University for their help in this endeavor.
Garifuna Settlement Day commemerates the arrival of the Garifuna people in eastern Central America and is a national holiday in Belize. Fishing trip!!
In about 2 hours of bottom fishing with light tackle and handlines we had a mixed bag of saucer-eyed porgy, yellow grunt, mutton snapper, and silk (actually "lane") snapper. Adrian got the big fish, the mutton snapper in the top of this photo. Richie has a family of 12, so most of these home with him (plus a nice dinner all around).
Two lizard fish made appearances while trolling. These are locally known as "sand barrow". A REAL barracuda would have been nicer, but they were still an interesting pick-up.
